Discussion:
A contradictory assumption of current physics
(too old to reply)
K***@YAHOO.COM
2005-07-26 21:48:01 UTC
Permalink
A contradictory assumption of current physics:

SR assumes that the leading edge of a light ray from a source will hit
the detector in the same frame of the source. This would mean that the
position and velocity of the leading edge of the light ray(the first
photon) is known exactly. This is a clear violation of the Uncertainty
Principle.

Ken Seto
Paul Cardinale
2005-07-26 23:40:44 UTC
Permalink
If we remove all the words that the lying bastard sub-moronic scum
runt-of-the-crackpots (aka "the kenseto") is incapable of
comprehending, we get:

> A _ _ of _ _:
>
> SR _ that the _ _ of a _ _ from a source will hit
> the _ in the same _ of the source. This would mean that the
> _ and _ of the _ _ of the _ _ (the first
> _ ) is known _. This is a clear _ of the _
> _.
Tom Roberts
2005-07-27 01:32:11 UTC
Permalink
***@YAHOO.COM wrote:
> A contradictory assumption of current physics:

No, it's jst a self-contradictory notion of yours. Nothing new there (:-().


> SR assumes that the leading edge of a light ray from a source will hit
> the detector in the same frame of the source.

Not true. The physical intersection of light ray and detector does not
occur in any frame, it is a geometrical process independent of frame.

What we basically OBSERVE is that when we aim a light source at a
detector that the light ray from the source does indeed hit the
detector. This is observed every day, even without fancy equipment --
just stare into a flashlight!


> This would mean that the
> position and velocity of the leading edge of the light ray(the first
> photon) is known exactly.

Nonsense. You clearly do not understand what photons are or how they are
used in modern physics.


Tom Roberts ***@lucent.com
K***@YAHOO.COM
2005-07-27 14:50:53 UTC
Permalink
> SR assumes that the leading edge of a light ray from a source will hit
> the detector in the same frame of the source.

Roberts:
Not true. The physical intersection of light ray and detector does not
occur in any frame, it is a geometrical process independent of frame.

Ken:
Don't give me your double talk.....Does SR assumes that the leading
edge of the light ray will hit the detector or not?
Roberts:
What we basically OBSERVE is that when we aim a light source at a
detector that the light ray from the source does indeed hit the
detector. This is observed every day, even without fancy equipment --
just stare into a flashlight!

Ken:
The question is: Is it the leading edge of the light ray that hits the
detector? BTW that's what SR assumes.


> This would mean that the
> position and velocity of the leading edge of the light ray(the first
> photon) is known exactly.

Roberts:
Nonsense. You clearly do not understand what photons are or how they
are
used in modern physics.

Ken:
The nonsense is on your part. If photon exists the leading edge of a
light ray must be the first photon.

Ken Seto
Tom Roberts
2005-07-27 18:31:03 UTC
Permalink
***@YAHOO.COM wrote:
> Does SR assumes that the leading
> edge of the light ray will hit the detector or not?

SR itself is silent on this.

But when real people aim real light sources at real detectors, they
observe that the light ray from the source does indeed hit the detector.
And there is no basis whatsoever to assume that the "leading edge"
somehow misses the detector while the rest of the ray hits it.

Photoelectric systems can transmit data at hundreds of giagbits per
second, and each pulse in the series has a leading edge, and the entire
pulse is a few femtoseconds long. So certainly the leading ~femtosecond
of the pulse hits the detector, AND IS DETECTED.


> If photon exists the leading edge of a
> light ray must be the first photon.

I repeat: you do not understand what photons really are. Such statements
as this simply do not make sense.


Tom Roberts ***@lucent.com
K***@YAHOO.COM
2005-07-27 20:24:08 UTC
Permalink
***@YAHOO.COM wrote:
> Does SR assumes that the leading
> edge of the light ray will hit the detector or not?

Roberts:
SR itself is silent on this.

Ken:
This is nonsense. In any TWLS experiment SR assumes that the returning
leading edge is the leading edge of the original light ray.

Roberts:
But when real people aim real light sources at real detectors, they
observe that the light ray from the source does indeed hit the
detector.
And there is no basis whatsoever to assume that the "leading edge"
somehow misses the detector while the rest of the ray hits it.

Ken:
But real people made the same bogus assumption that the leading edge of
the light ray will hit the detector. If absolute motion in the vertical
direction exist then the leading edge will miss the detector. The
experiment I described in the following link will settle this
definitively.
<http://www.geocities.com/kn_seto/Experiment.pdf>

Roberts:
Photoelectric systems can transmit data at hundreds of giagbits per
second, and each pulse in the series has a leading edge, and the entire

pulse is a few femtoseconds long. So certainly the leading ~femtosecond

of the pulse hits the detector, AND IS DETECTED.

Seto:
Transmission through a fiber optic cable is different than transmission
through open air.


Ken Seto
Jerry T
2005-07-28 19:05:40 UTC
Permalink
***@YAHOO.COM wrote:
> ***@YAHOO.COM wrote:
> > Does SR assumes that the leading
> > edge of the light ray will hit the detector or not?
>
> Roberts:
> SR itself is silent on this.
>
> Ken:
> This is nonsense. In any TWLS experiment SR assumes that the returning
> leading edge is the leading edge of the original light ray.
>
> Roberts:
> But when real people aim real light sources at real detectors, they
> observe that the light ray from the source does indeed hit the
> detector.
> And there is no basis whatsoever to assume that the "leading edge"
> somehow misses the detector while the rest of the ray hits it.
>
> Ken:
> But real people made the same bogus assumption that the leading edge of
> the light ray will hit the detector. If absolute motion in the vertical
> direction exist then the leading edge will miss the detector. The
> experiment I described in the following link will settle this
> definitively.
> <http://www.geocities.com/kn_seto/Experiment.pdf>
>
> Roberts:
> Photoelectric systems can transmit data at hundreds of giagbits per
> second, and each pulse in the series has a leading edge, and the entire
>
> pulse is a few femtoseconds long. So certainly the leading ~femtosecond

no, nobody knows actually what happen in a pmt

the pulses are averaged, you cant detect femtoseconds, at best at giga

>
> of the pulse hits the detector, AND IS DETECTED.
>
> Seto:
> Transmission through a fiber optic cable is different than transmission
> through open air.
>
>
> Ken Seto
Jerry T
2005-07-28 19:00:58 UTC
Permalink
Tom Roberts wrote:
> ***@YAHOO.COM wrote:
> > Does SR assumes that the leading
> > edge of the light ray will hit the detector or not?
>
> SR itself is silent on this.
>
> But when real people aim real light sources at real detectors, they
> observe that the light ray from the source does indeed hit the detector.
> And there is no basis whatsoever to assume that the "leading edge"
> somehow misses the detector while the rest of the ray hits it.
>
> Photoelectric systems can transmit data at hundreds of giagbits per
> second, and each pulse in the series has a leading edge, and the entire
> pulse is a few femtoseconds long. So certainly the leading ~femtosecond
> of the pulse hits the detector, AND IS DETECTED.

or not, there are a lot of bad things which can happen
and happens

you may think that it was the photon, but actually the
detector detected somthin complitly else

you nee averages, and averages are not detectings

>
>
> > If photon exists the leading edge of a
> > light ray must be the first photon.
>
> I repeat: you do not understand what photons really are. Such statements
> as this simply do not make sense.

fine, explain please, for instance, what the 81 counted photons are

>
>
> Tom Roberts ***@lucent.com
sue jahn
2005-07-27 15:14:21 UTC
Permalink
<***@YAHOO.COM> wrote in message news:***@g44g2000cwa.googlegroups.com...
> A contradictory assumption of current physics:
>
> SR assumes that the leading edge of a light ray from a source will hit
> the detector in the same frame of the source. This would mean that the
> position and velocity of the leading edge of the light ray(the first
> photon) is known exactly. This is a clear violation of the Uncertainty
> Principle.
>
> Ken Seto
>
No
SR assumes there is an apparent conflict between Maxwell's
equations and the principle of relativity. The issue is *apparently*
resolved through the use of an imaginary time axis in the far-field
to compensate for Maxwell-Heaviside's omission of imaginary
vectors (reactace) in the near-field.

It is completely pridictable and has nothing to do with the
Heisinberg uncertainty principle.

http://farside.ph.utexas.edu/teaching/em1/lectures/node46.html
http://arxiv.org/abs/physics/0204034

Sue...
Tom Roberts
2005-07-27 17:47:12 UTC
Permalink
sue jahn wrote:
> SR assumes there is an apparent conflict between Maxwell's
> equations and the principle of relativity.

Where do you get this stuff?? -- you must just make it up, as it is
completely wrong.

SR shows that there is no such conflict. It was between ~1860s - 1905
that such a conflict seemed to apply. There were other attempts to
resolve this conflict, notably by Lorentz, but they all fell short. SR
succeeded.


Tom Roberts ***@lucent.com
sue jahn
2005-07-27 17:54:46 UTC
Permalink
"Tom Roberts" <***@lucent.com> wrote in message news:dc8hb1$***@netnews.net.lucent.com...
sue jahn wrote:: SR assumes there is an apparent conflict between Maxwell's
equations and the principle of relativity.
>
"Tom Roberts" wrote: Where do you get this stuff?? -- you must just make it up, as it is
> completely wrong.

Completely wrong Tom ?
Your words ... not mine

I got the words from here:

VII. The Apparent Incompatibility of the Law of Propagation of Light with the Principle of Relativity
--Albert Einstein (1879-1955). Relativity: The Special and General Theory. 1920
http://www.bartleby.com/173/7.html

Sue...

>
> SR shows that there is no such conflict. It was between ~1860s - 1905
> that such a conflict seemed to apply. There were other attempts to
> resolve this conflict, notably by Lorentz, but they all fell short. SR
> succeeded.
>
>
> Tom Roberts ***@lucent.com
Paul Cardinale
2005-07-27 18:31:27 UTC
Permalink
sue jahn wrote:
> "Tom Roberts" <***@lucent.com> wrote in message news:dc8hb1$***@netnews.net.lucent.com...
> sue jahn wrote:: SR assumes there is an apparent conflict between Maxwell's
> equations and the principle of relativity.
> >
> "Tom Roberts" wrote: Where do you get this stuff?? -- you must just make it up, as it is
> > completely wrong.
>
> Completely wrong Tom ?
> Your words ... not mine
>
> I got the words from here:
>
> VII. The Apparent Incompatibility of the Law of Propagation of Light with the Principle of Relativity
> --Albert Einstein (1879-1955). Relativity: The Special and General Theory. 1920
> http://www.bartleby.com/173/7.html
>
> Sue...
>

There are three possibilities here:
1) You didn't read the last paragraph.
2) You read it, but didn't understand it.
3) You discarded the last paragraph, taking other portions out ot
context in order to mislead.

Paul Cardinale
sue jahn
2005-07-27 18:28:02 UTC
Permalink
"Paul Cardinale" <***@volcanomail.com> wrote in message news:***@g44g2000cwa.googlegroups.com...
>
>
> sue jahn wrote:
> > "Tom Roberts" <***@lucent.com> wrote in message news:dc8hb1$***@netnews.net.lucent.com...
> > sue jahn wrote:: SR assumes there is an apparent conflict between Maxwell's
> > equations and the principle of relativity.
> > >
> > "Tom Roberts" wrote: Where do you get this stuff?? -- you must just make it up, as it is
> > > completely wrong.
> >
> > Completely wrong Tom ?
> > Your words ... not mine
> >
> > I got the words from here:
> >
> > VII. The Apparent Incompatibility of the Law of Propagation of Light with the Principle of Relativity
> > --Albert Einstein (1879-1955). Relativity: The Special and General Theory. 1920
> > http://www.bartleby.com/173/7.html
> >
> > Sue...
> >
>
> There are three possibilities here:
> 1) You didn't read the last paragraph.
> 2) You read it, but didn't understand it.
> 3) You discarded the last paragraph, taking other portions out ot
> context in order to mislead.
>
> Paul Cardinale

If that s that a comment on reading skills you might
reconsider how it is directed.

Sue...

>
m***@cars3.uchicago.edu
2005-07-27 20:17:21 UTC
Permalink
In article <42e7d4a9$0$18649$***@news.sunsite.dk>, "sue jahn" <***@yahoo.com.au> writes:
>
>"Paul Cardinale" <***@volcanomail.com> wrote in message news:***@g44g2000cwa.googlegroups.com...
>>
>>
>> sue jahn wrote:
>> > "Tom Roberts" <***@lucent.com> wrote in message news:dc8hb1$***@netnews.net.lucent.com...
>> > sue jahn wrote:: SR assumes there is an apparent conflict between Maxwell's
>> > equations and the principle of relativity.
>> > >
>> > "Tom Roberts" wrote: Where do you get this stuff?? -- you must just make it up, as it is
>> > > completely wrong.
>> >
>> > Completely wrong Tom ?
>> > Your words ... not mine
>> >
>> > I got the words from here:
>> >
>> > VII. The Apparent Incompatibility of the Law of Propagation of Light with the Principle of Relativity
>> > --Albert Einstein (1879-1955). Relativity: The Special and General Theory. 1920
>> > http://www.bartleby.com/173/7.html
>> >
>> > Sue...
>> >
>>
>> There are three possibilities here:
>> 1) You didn't read the last paragraph.
>> 2) You read it, but didn't understand it.
>> 3) You discarded the last paragraph, taking other portions out ot
>> context in order to mislead.
>>
>> Paul Cardinale
>
>If that s that a comment on reading skills you might
>reconsider how it is directed.
>
It is directed as it *should*.

Mati Meron | "When you argue with a fool,
***@cars.uchicago.edu | chances are he is doing just the same"
Jerry T
2005-07-28 19:14:22 UTC
Permalink
Paul Cardinale wrote:
> sue jahn wrote:
> > "Tom Roberts" <***@lucent.com> wrote in message news:dc8hb1$***@netnews.net.lucent.com...
> > sue jahn wrote:: SR assumes there is an apparent conflict between Maxwell's
> > equations and the principle of relativity.
> > >
> > "Tom Roberts" wrote: Where do you get this stuff?? -- you must just make it up, as it is
> > > completely wrong.
> >
> > Completely wrong Tom ?
> > Your words ... not mine
> >
> > I got the words from here:
> >
> > VII. The Apparent Incompatibility of the Law of Propagation of Light with the Principle of Relativity
> > --Albert Einstein (1879-1955). Relativity: The Special and General Theory. 1920
> > http://www.bartleby.com/173/7.html
> >
> > Sue...
> >
>
> There are three possibilities here:
> 1) You didn't read the last paragraph.
> 2) You read it, but didn't understand it.
> 3) You discarded the last paragraph, taking other portions out ot
> context in order to mislead.

anybody could write this bullshit

>
> Paul Cardinale

i never saw an inteligibel explanaition coming from you, never

wake me up when you have one
v***@cox.net
2005-07-27 18:58:30 UTC
Permalink
sue jahn wrote:
> "Tom Roberts" <***@lucent.com> wrote in message news:dc8hb1$***@netnews.net.lucent.com...
> sue jahn wrote:: SR assumes there is an apparent conflict between Maxwell's
> equations and the principle of relativity.
> >
> "Tom Roberts" wrote: Where do you get this stuff?? -- you must just make it up, as it is
> > completely wrong.
>
> Completely wrong Tom ?
> Your words ... not mine
>
> I got the words from here:
>
> VII. The Apparent Incompatibility of the Law of Propagation of Light with the Principle of Relativity
> --Albert Einstein (1879-1955). Relativity: The Special and General Theory. 1920
> http://www.bartleby.com/173/7.html
>
> Sue...
>
> >
> > SR shows that there is no such conflict. It was between ~1860s - 1905
> > that such a conflict seemed to apply. There were other attempts to
> > resolve this conflict, notably by Lorentz, but they all fell short. SR
> > succeeded.
> >
> >
> > Tom Roberts ***@lucent.com


Tom is correct. Read the page you provided. Last paragraph: " At this
juncture the theory of relativity entered the arena. As a result of an
analysis of the physical conceptions of time and space, it became
evident that in reality there is not the least incompatibility between
the principle of relativity and the law of propagation of light, and
that by systematically holding fast to both these laws a logically
rigid theory could be arrived at. This theory has been called the
special theory of relativity to distinguish it from the extended
theory, with which we shall deal later. In the following pages we shall
present the fundamental ideas of the special theory of relativity."


James
sue jahn
2005-07-27 19:04:48 UTC
Permalink
<***@cox.net> wrote in message news:***@g14g2000cwa.googlegroups.com...
>
>
> sue jahn wrote:
> > "Tom Roberts" <***@lucent.com> wrote in message news:dc8hb1$***@netnews.net.lucent.com...
> > sue jahn wrote:: SR assumes there is an apparent conflict between Maxwell's
> > equations and the principle of relativity.
> > >
> > "Tom Roberts" wrote: Where do you get this stuff?? -- you must just make it up, as it is
> > > completely wrong.
> >
> > Completely wrong Tom ?
> > Your words ... not mine
> >
> > I got the words from here:
> >
> > VII. The Apparent Incompatibility of the Law of Propagation of Light with the Principle of Relativity
> > --Albert Einstein (1879-1955). Relativity: The Special and General Theory. 1920
> > http://www.bartleby.com/173/7.html
> >
> > Sue...
> >
> > >
> > > SR shows that there is no such conflict. It was between ~1860s - 1905
> > > that such a conflict seemed to apply. There were other attempts to
> > > resolve this conflict, notably by Lorentz, but they all fell short. SR
> > > succeeded.
> > >
> > >
> > > Tom Roberts ***@lucent.com
>
>
> Tom is correct. Read the page you provided. Last paragraph: " At this
> juncture the theory of relativity entered the arena. As a result of an
> analysis of the physical conceptions of time and space, it became
> evident that in reality there is not the least incompatibility between
> the principle of relativity and the law of propagation of light, and
> that by systematically holding fast to both these laws a logically
> rigid theory could be arrived at. This theory has been called the
> special theory of relativity to distinguish it from the extended
> theory, with which we shall deal later. In the following pages we shall
> present the fundamental ideas of the special theory of relativity."
>
>
> James

I see.

When Tom quotes Einsten he is correct.
But when I quote Einstein ~I must just make it up~ and
~it is completely wrong.~

Sheesh!

Sue...




>
Paul Cardinale
2005-07-28 23:03:00 UTC
Permalink
sue jahn wrote:
> <***@cox.net> wrote in message news:***@g14g2000cwa.googlegroups.com...
> >
> >
> > sue jahn wrote:
> > > "Tom Roberts" <***@lucent.com> wrote in message news:dc8hb1$***@netnews.net.lucent.com...
> > > sue jahn wrote:: SR assumes there is an apparent conflict between Maxwell's
> > > equations and the principle of relativity.
> > > >
> > > "Tom Roberts" wrote: Where do you get this stuff?? -- you must just make it up, as it is
> > > > completely wrong.
> > >
> > > Completely wrong Tom ?
> > > Your words ... not mine
> > >
> > > I got the words from here:
> > >
> > > VII. The Apparent Incompatibility of the Law of Propagation of Light with the Principle of Relativity
> > > --Albert Einstein (1879-1955). Relativity: The Special and General Theory. 1920
> > > http://www.bartleby.com/173/7.html
> > >
> > > Sue...
> > >
> > > >
> > > > SR shows that there is no such conflict. It was between ~1860s - 1905
> > > > that such a conflict seemed to apply. There were other attempts to
> > > > resolve this conflict, notably by Lorentz, but they all fell short. SR
> > > > succeeded.
> > > >
> > > >
> > > > Tom Roberts ***@lucent.com
> >
> >
> > Tom is correct. Read the page you provided. Last paragraph: " At this
> > juncture the theory of relativity entered the arena. As a result of an
> > analysis of the physical conceptions of time and space, it became
> > evident that in reality there is not the least incompatibility between
> > the principle of relativity and the law of propagation of light, and
> > that by systematically holding fast to both these laws a logically
> > rigid theory could be arrived at. This theory has been called the
> > special theory of relativity to distinguish it from the extended
> > theory, with which we shall deal later. In the following pages we shall
> > present the fundamental ideas of the special theory of relativity."
> >
> >
> > James
>
> I see.
>
> When Tom quotes Einsten he is correct.
> But when I quote Einstein ~I must just make it up~ and
> ~it is completely wrong.~
>
> Sheesh!
>

When you quote something out of context, getting it completely wrong,
then you are completely wrong.

Paul Cardinale
Jerry T
2005-07-28 19:12:12 UTC
Permalink
***@cox.net wrote:
> sue jahn wrote:
> > "Tom Roberts" <***@lucent.com> wrote in message news:dc8hb1$***@netnews.net.lucent.com...
> > sue jahn wrote:: SR assumes there is an apparent conflict between Maxwell's
> > equations and the principle of relativity.
> > >
> > "Tom Roberts" wrote: Where do you get this stuff?? -- you must just make it up, as it is
> > > completely wrong.
> >
> > Completely wrong Tom ?
> > Your words ... not mine
> >
> > I got the words from here:
> >
> > VII. The Apparent Incompatibility of the Law of Propagation of Light with the Principle of Relativity
> > --Albert Einstein (1879-1955). Relativity: The Special and General Theory. 1920
> > http://www.bartleby.com/173/7.html
> >
> > Sue...
> >
> > >
> > > SR shows that there is no such conflict. It was between ~1860s - 1905
> > > that such a conflict seemed to apply. There were other attempts to
> > > resolve this conflict, notably by Lorentz, but they all fell short. SR
> > > succeeded.
> > >
> > >
> > > Tom Roberts ***@lucent.com
>
>
> Tom is correct. Read the page you provided. Last paragraph:

this is bullshit, show the equations proving no conflict

tom is confussed, the detected photons are
<averaged> not detected, photons cant be detected,
¨
light yes, but not photons

ken and sue are right


>" At this
> juncture the theory of relativity entered the arena. As a result of an
> analysis of the physical conceptions of time and space, it became
> evident that in reality there is not the least incompatibility between
> the principle of relativity and the law of propagation of light, and
> that by systematically holding fast to both these laws a logically
> rigid theory could be arrived at. This theory has been called the
> special theory of relativity to distinguish it from the extended
> theory, with which we shall deal later. In the following pages we shall
> present the fundamental ideas of the special theory of relativity."
>
>
> James
bz
2005-07-28 22:41:01 UTC
Permalink
"Jerry T" <***@soon.com> wrote in news:1122577932.826500.62060
@o13g2000cwo.googlegroups.com:

> tom is confussed, the detected photons are
> <averaged> not detected, photons cant be detected,
>

google for
single photon dual slit experiments
There are many such.

They detect single photons.


Google for micro dot single photon

you will see that there are devices the emit single photons.

http://ipeqwww.epfl.ch/qd/html/singleqddevices.htm






--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+***@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap
Tom Roberts
2005-08-01 14:48:33 UTC
Permalink
Jerry T wrote:
> tom is confussed, the detected photons are
> <averaged> not detected,

Sometimes yes, sometimes not, it depends on WHAT IS BEING MEASURED.


> photons cant be detected,

Not true. Phototubes easily detect single UV photons, and NaI crystals
easily convert single gamma ray photons into multiple UV/visible
photons, which are easily detected by phototubes.

And look up Visible Light Photon Counters (VLPCs). They are cooled to
cryogenic temperatures and detect individual visible photons.


Tom Roberts ***@lucent.com
k***@erinet.com
2005-08-02 15:01:44 UTC
Permalink
Roberts:
Not true. Phototubes easily detect single UV photons, and NaI crystals
easily convert single gamma ray photons into multiple UV/visible
photons, which are easily detected by phototubes.

Seto:
So are you saying that you can generate and detect a single UV photon?
And you can generate a single gamma photon and convert it into multiple
UV/visible photons? Doesn't that violate the Uncertainty Principle?

Ken Seto
Sam Wormley
2005-08-02 15:12:36 UTC
Permalink
***@erinet.com wrote:
> Roberts:
> Not true. Phototubes easily detect single UV photons, and NaI crystals
> easily convert single gamma ray photons into multiple UV/visible
> photons, which are easily detected by phototubes.
>
> Seto:
> So are you saying that you can generate and detect a single UV photon?
> And you can generate a single gamma photon and convert it into multiple
> UV/visible photons? Doesn't that violate the Uncertainty Principle?
>
> Ken Seto
>

Ken--The uncertainty principle doesn't apply to the existence or non
existence of a single photon, but to the uncertainty between conjugate
quantum mechanical variables is approximately h.
http://scienceworld.wolfram.com/physics/UncertaintyPrinciple.html
Tom Roberts
2005-08-03 00:40:01 UTC
Permalink
***@erinet.com wrote:
> Roberts:
> Not true. Phototubes easily detect single UV photons, and NaI crystals
> easily convert single gamma ray photons into multiple UV/visible
> photons, which are easily detected by phototubes.
>
> Seto:
> So are you saying that you can generate and detect a single UV photon?
> And you can generate a single gamma photon and convert it into multiple
> UV/visible photons?

Yes to both. Though most processes that generate photons do so in
bunches rather than singly, and there are invariably "infrared
divergences" that make it impossible to know how many additional
low-energy photons were also created....


> Doesn't that violate the Uncertainty Principle?

No.


Tom Roberts ***@lucent.com
kenseto
2005-08-05 20:44:19 UTC
Permalink
"Tom Roberts" <***@lucent.com> wrote in message
news:BnUHe.517$***@newssvr24.news.prodigy.net...
> ***@erinet.com wrote:
> > Roberts:
> > Not true. Phototubes easily detect single UV photons, and NaI crystals
> > easily convert single gamma ray photons into multiple UV/visible
> > photons, which are easily detected by phototubes.
> >
> > Seto:
> > So are you saying that you can generate and detect a single UV photon?
> > And you can generate a single gamma photon and convert it into multiple
> > UV/visible photons?
>
> Yes to both. Though most processes that generate photons do so in
> bunches rather than singly, and there are invariably "infrared
> divergences" that make it impossible to know how many additional
> low-energy photons were also created....
>
>
> > Doesn't that violate the Uncertainty Principle?
>
> No.

Why not?...you know the path, the speed and the position of a single photon
from birth to detection. Why isn't that a violation of the UP?

Ken Seto
Tom Roberts
2005-08-06 00:44:58 UTC
Permalink
kenseto wrote:
> "Tom Roberts" <***@lucent.com> wrote in message
> news:BnUHe.517$***@newssvr24.news.prodigy.net...
>>***@erinet.com wrote:
>>>Doesn't that violate the Uncertainty Principle?
>>No.
>
> Why not?...you know the path, the speed and the position of a single photon
> from birth to detection. Why isn't that a violation of the UP?

Because you only know the location of the source to within the size of
its container (etc.), and only know the location of the detection to the
resolution of the detector. You don't know the time of emission at all,
and only know the time of detection to within the resolution of the
detector. These resolutions are usually quite large compared to
Heisenberg limits -- for example phototubes have time resolutions ~100ps
and spatial resolutions ~1cm; VLPCs have time resolutions ~10ns and
spatial resolutions ~1mm. But the uncertainty principle relates time
accuracy to energy accuracy, and for these detectors energy resolutions
are ~10% or greater (sometimes MUCH greater). (It also relates position
accuracy to momentum accuracy, but these detectors don't measure
momentum at all.)

Perhaps you should LEARN what Heisenberg's uncertainty principle
actually says, instead of repeatedly making completely wrong guesses.


Tom Roberts ***@lucent.com
kenseto
2005-08-06 16:31:24 UTC
Permalink
"Tom Roberts" <***@lucent.com> wrote in message
news:eKTIe.165$***@newssvr22.news.prodigy.net...
> kenseto wrote:
> > "Tom Roberts" <***@lucent.com> wrote in message
> > news:BnUHe.517$***@newssvr24.news.prodigy.net...
> >>***@erinet.com wrote:
> >>>Doesn't that violate the Uncertainty Principle?
> >>No.
> >
> > Why not?...you know the path, the speed and the position of a single
photon
> > from birth to detection. Why isn't that a violation of the UP?
>
> Because you only know the location of the source to within the size of
> its container (etc.), and only know the location of the detection to the
> resolution of the detector. You don't know the time of emission at all,
> and only know the time of detection to within the resolution of the
> detector.

Then how do you know that the source only emitted one photon and how do you
know it is that one photon is detected by the detector?

Ken Seto
Dirk Van de moortel
2005-08-06 16:48:51 UTC
Permalink
"kenseto" <***@erinet.com> wrote in message news:wB5Je.49795$***@tornado.ohiordc.rr.com...
>
> "Tom Roberts" <***@lucent.com> wrote in message
> news:eKTIe.165$***@newssvr22.news.prodigy.net...
> > kenseto wrote:
> > > "Tom Roberts" <***@lucent.com> wrote in message
> > > news:BnUHe.517$***@newssvr24.news.prodigy.net...
> > >>***@erinet.com wrote:
> > >>>Doesn't that violate the Uncertainty Principle?
> > >>No.
> > >
> > > Why not?...you know the path, the speed and the position of a single
> > > photon from birth to detection. Why isn't that a violation of the UP?
> >
> > Because you only know the location of the source to within the size of
> > its container (etc.), and only know the location of the detection to the
> > resolution of the detector. You don't know the time of emission at all,
> > and only know the time of detection to within the resolution of the
> > detector.
>
> Then how do you know that the source only emitted one photon and how do you
> know it is that one photon is detected by the detector?

When you detect a photon in the detector, you just know that
the emitter emitted it. You don't know when.

Dirk Vdm
the softrat
2005-08-07 04:37:18 UTC
Permalink
On Sat, 06 Aug 2005 16:31:24 GMT, in sci.physics "kenseto"
<***@erinet.com> wrote:
>
>Then how do you know that the source only emitted one photon and how do you
>know it is that one photon is detected by the detector?
>
>Ken Seto
>
Because my mommy told me so, jerkwit!

Ever heard of Conservation of Energy? Frequency? Wave length? Cause
and effect?

I thought not.

the softrat
Sometimes I get so tired of the taste of my own toes.
mailto:***@pobox.com
--
Hard work pays off in the future, laziness pays off now. --
Steven Wright
m***@internetCDS.com
2005-08-07 06:16:23 UTC
Permalink
the softrat wrote:
> On Sat, 06 Aug 2005 16:31:24 GMT, in sci.physics "kenseto"
> <***@erinet.com> wrote:
> >
> >Then how do you know that the source only emitted one photon and how do you
> >know it is that one photon is detected by the detector?
> >
> >Ken Seto
> >
> Because my mommy told me so, jerkwit!

Did your mommy tell you what 1+1 equals?

If someone asks you how you know that
1+1 equals 2 what do you say?


> Ever heard of Conservation of Energy? Frequency? Wave length? Cause
> and effect?
>
> I thought not.
>
> the softrat
> Sometimes I get so tired of the taste of my own toes.
> mailto:***@pobox.com
> --
> Hard work pays off in the future, laziness pays off now. --
> Steven Wright
the softrat
2005-08-07 10:43:55 UTC
Permalink
On 6 Aug 2005 23:16:23 -0700, ***@internetCDS.com wrote:
>
>If someone asks you how you know that
>1+1 equals 2 what do you say?
>
It's By Definition, Genius.


the softrat
Sometimes I get so tired of the taste of my own toes.
mailto:***@pobox.com
--
A hush fell over the courtroom, injuring six.
m***@internetCDS.com
2005-08-08 04:19:29 UTC
Permalink
the softrat wrote:
> On 6 Aug 2005 23:16:23 -0700, ***@internetCDS.com wrote:
> >
> >If someone asks you how you know that
> >1+1 equals 2 what do you say?
> >
> It's By Definition, Genius.
Wrong answer Moron.
The correct answer is You can See that it is.

Nobody needs to teach you the truth.
You can always see it for yourself.

No need for teachers!!



>
> the softrat
> Sometimes I get so tired of the taste of my own toes.
> mailto:***@pobox.com
> --
> A hush fell over the courtroom, injuring six.
the softrat
2005-08-08 04:46:01 UTC
Permalink
On 7 Aug 2005 21:19:29 -0700, ***@internetCDS.com wrote:
>the softrat wrote:
>> On 6 Aug 2005 23:16:23 -0700, ***@internetCDS.com wrote:
>> >
>> >If someone asks you how you know that
>> >1+1 equals 2 what do you say?
>> >
>> It's By Definition, Genius.

>Wrong answer Moron.
>The correct answer is You can See that it is.
>
"What we have here, Spock, is a creature completely without Logic.
Please, use your tricorder to see if it is a Troll."

...


the softrat
Sometimes I get so tired of the taste of my own toes.
mailto:***@pobox.com
--
People are more violently opposed to fur than leather because
it's safer to pick on rich women than biker gangs.
T Wake
2005-08-08 16:36:08 UTC
Permalink
<***@internetCDS.com> wrote in message
news:***@g44g2000cwa.googlegroups.com...
>
> the softrat wrote:
>> On 6 Aug 2005 23:16:23 -0700, ***@internetCDS.com wrote:
>> >
>> >If someone asks you how you know that
>> >1+1 equals 2 what do you say?
>> >
>> It's By Definition, Genius.
> Wrong answer Moron.
> The correct answer is You can See that it is.

Nope. If you look at it 1+1 should equal 11. Your belief that everything is
intrisically obvious is a weak one.

> Nobody needs to teach you the truth.
> You can always see it for yourself.

Nope. Totally wrong here. This is the line of thinking that makes the sun
rotate around the Earth.

> No need for teachers!!

You are a prime example of what the lack of teaching causes.
T Wake
2005-08-07 13:33:47 UTC
Permalink
<***@internetCDS.com> wrote in message
news:***@o13g2000cwo.googlegroups.com...
>
> Did your mommy tell you what 1+1 equals?
>
> If someone asks you how you know that
> 1+1 equals 2 what do you say?
>

Nick, does 1 + 1 always = 2?

Can you show how it was proven that 1+1=2 is correct?
The Ghost In The Machine
2005-08-07 19:00:06 UTC
Permalink
In sci.physics, T Wake
<***@hotmail.com>
wrote
on Sun, 7 Aug 2005 14:33:47 +0100
<***@pipex.net>:
>
> <***@internetCDS.com> wrote in message
> news:***@o13g2000cwo.googlegroups.com...
>>
>> Did your mommy tell you what 1+1 equals?
>>
>> If someone asks you how you know that
>> 1+1 equals 2 what do you say?
>>
>
> Nick, does 1 + 1 always = 2?
>
> Can you show how it was proven that 1+1=2 is correct?
>

That could get *very* messy. Most people simply *define*
1+1 = 2, or have definitions similar to Peano's Axioms which
indicate 1 = 0' (where ' indicates "successor to") and
2 = 0'' = 1', and define '+' thusly:

0 + 0 = 0
a + b' = (a+b)'
a' + b = (a+b)'

or some such. Therefore:

1 + 1 = (0 + 1)' = (0 + 0)'' = 0'' = 2.

However, my understanding is that Newton, in his work _Principia
Mathematica_, took a volume and a half to reach this point,
and I have no idea what path he took.

Or one can get into finite fields. The field Z[2] in particular
has two elements, which are 0 and 1. This is a full-fledged
unordered field, though not all that useful for, say, bridge-building.
However, one can add, subtract, and multiply all elements,
and division by nonzero elements -- erm, element -- is always possible.

Or one can get into symbolic logic -- which modifies the definition
of '+'. In this case one has two choices: exclusive OR is similar
to addition in Z[2] and in fact has an identical truth table,
if one ignores the carry. Inclusive OR, by contrast, has 1+1 = 1.

Or one can get into ridiculously pedantic encoding issues.
In ASCII, for instance, 1+1 = 0x312B31 or 0x31 0x2B 0x31.
That's not 2 (0x32), obviously -- but it's also not all that
interesting as an objection. In EBCDIC, at least according
to 'dd', 1+1 = 0xF1 0x4E 0xF1 and 2 = 0xF2. Since '=' is
0x7E, '1+1=2' becomes 'ñNñ~ò', which looks like line noise
to most of us. :-)

(I'm an engineer. That's probably my best excuse for this
line of thinking. :-) )

--
#191, ***@earthlink.net
It's still legal to go .sigless.
kenseto
2005-08-07 17:09:14 UTC
Permalink
"the softrat" <***@pobox.com> wrote in message
news:***@4ax.com...
> On Sat, 06 Aug 2005 16:31:24 GMT, in sci.physics "kenseto"
> <***@erinet.com> wrote:
> >
> >Then how do you know that the source only emitted one photon and how do
you
> >know it is that one photon is detected by the detector?
> >
> >Ken Seto
> >
> Because my mommy told me so, jerkwit!
>
> Ever heard of Conservation of Energy? Frequency? Wave length? Cause
> and effect?
>
> I thought not.

Fucking idiot runt.
The Ghost In The Machine
2005-08-07 19:00:07 UTC
Permalink
In sci.physics.relativity, kenseto
<***@erinet.com>
wrote
on Sun, 07 Aug 2005 17:09:14 GMT
<_erJe.65396$***@tornado.ohiordc.rr.com>:
>
> "the softrat" <***@pobox.com> wrote in message
> news:***@4ax.com...
>> On Sat, 06 Aug 2005 16:31:24 GMT, in sci.physics "kenseto"
>> <***@erinet.com> wrote:
>> >
>> >Then how do you know that the source only emitted one
>> >photon and how do you know it is that one photon is
>> >detected by the detector?
>> >
>> >Ken Seto
>> >
>> Because my mommy told me so, jerkwit!
>>
>> Ever heard of Conservation of Energy? Frequency? Wave length? Cause
>> and effect?
>>
>> I thought not.
>
> Fucking idiot runt.
>

It's worth noting here that Conservation of Mass-Energy
has vanished with the advent of GR.

Briefly put, I drop a rock, which falls a bit, heats the
ground and the air. Where did that energy come from?
There's no force involved. (It just looks an awful lot
like an external force.)

Of course I need energy to pick up the rock again, to reset
the system to the initial state. This energy is largely
chemical, though one can contemplate nuclear or solar
energy in certain cases (e.g., battery-powered forklifts).

Since E = hv one gets into interesting territory if a laser
is moving towards or away from the observer. The wavelength
varies as sqrt(1-v/c)/sqrt(1+v/c), but I'm not sure exactly
what that does to the beam power.

--
#191, ***@earthlink.net
It's still legal to go .sigless.
s***@gmail.com
2005-08-06 10:02:35 UTC
Permalink
kenseto wrote:
> > > Doesn't that violate the Uncertainty Principle?
> >
> > No.
>
> Why not?...you know the path, the speed and the position of a single photon
> from birth to detection. Why isn't that a violation of the UP?


Heiseinberg's uncertainty applies only to predictive measurements.
There is nothing preventing you from knowing where a photon was and how
much momentum it had with arbitrary certainty.

That being said you will not be able to predict the photons state in
the future with the same certainty. In fact you will find that the more
certain you knew a photons previous state the less certain you can
predict it's future state. So much so that if you knew exactly where it
was and how much momentum it carried, you will not be able to predict
anything new about this photon after that measurement (you could
interpret this as fully absorbing the photon).

Also, there is no such thing as a single photon detector since it
always has a chance of failing (i.e. missing a photon once in a while).
This arises due to infrared divergence. By reducing the frequency
spectrum of the photons you are trying to detect you improve the
efficiency, but you will never find a perfect single photon detector as
others have stated.


> Ken Seto
Tom Roberts
2005-08-06 12:10:58 UTC
Permalink
***@gmail.com wrote:
> Heiseinberg's uncertainty applies only to predictive measurements.
> There is nothing preventing you from knowing where a photon was and how
> much momentum it had with arbitrary certainty.

This is not true. You will find that if you try to make a momentum
measuring device arbitrarily small, its momentum resolution will grow
arbitrarily large. And if you attempt to make a detector with
arbitrarily good time resolution, its energy resolution will be
arbitrarily bad. In both cases the uncertainty principle applies. This
is just basic QM, and the inherent mathematical relationship between
distributions of conjugate variables (i.e. variables related by a
Fourier trnsform).


> Also, there is no such thing as a single photon detector since it
> always has a chance of failing (i.e. missing a photon once in a while).

Of course real detectors are never perfect. VLPCs detect single visible
light photons with a quantum efficiency of ~80%. But sure, they don't
detect deep infrared photons at all. The point is they DO detect single
photons most of the time. And for typical scintillating fibers the
single-photon energy peak is cleanly separated (i.e. > 90%) from 0 and
from the 2 photon peak.


Tom Roberts ***@lucent.com
Mike
2005-08-06 14:37:41 UTC
Permalink
Tom Roberts wrote:
> ***@gmail.com wrote:
> > Heiseinberg's uncertainty applies only to predictive measurements.
> > There is nothing preventing you from knowing where a photon was and how
> > much momentum it had with arbitrary certainty.
>
> This is not true. You will find that if you try to make a momentum
> measuring device arbitrarily small, its momentum resolution will grow
> arbitrarily large.

Did you mean the position resolution will grow arbitrarily large? Or
you meant "if you try to make a position measuring devide arbitrarily
small...", I guess the latter.

Mike



> And if you attempt to make a detector with
> arbitrarily good time resolution, its energy resolution will be
> arbitrarily bad. In both cases the uncertainty principle applies. This
> is just basic QM, and the inherent mathematical relationship between
> distributions of conjugate variables (i.e. variables related by a
> Fourier trnsform).
>
>
> > Also, there is no such thing as a single photon detector since it
> > always has a chance of failing (i.e. missing a photon once in a while).
>
> Of course real detectors are never perfect. VLPCs detect single visible
> light photons with a quantum efficiency of ~80%. But sure, they don't
> detect deep infrared photons at all. The point is they DO detect single
> photons most of the time. And for typical scintillating fibers the
> single-photon energy peak is cleanly separated (i.e. > 90%) from 0 and
> from the 2 photon peak.
>
>
> Tom Roberts ***@lucent.com
Tom Roberts
2005-08-06 17:44:41 UTC
Permalink
Mike wrote:
> Tom Roberts wrote:
>>You will find that if you try to make a momentum
>>measuring device arbitrarily small, its momentum resolution will grow
>>arbitrarily large.
>
> Did you mean the position resolution will grow arbitrarily large?

I meant what I said. If you make the detector smaller, its position
resolution gets smaller too -- that is, better. But beyond a certain
point, which in practice is usually well above the Heisenberg limit,
making it smaller makes its momentum resolution larger.


Tom Roberts ***@lucent.com
Mike
2005-08-06 18:58:22 UTC
Permalink
Tom Roberts wrote:
> Mike wrote:
> > Tom Roberts wrote:
> >>You will find that if you try to make a momentum
> >>measuring device arbitrarily small, its momentum resolution will grow
> >>arbitrarily large.
> >
> > Did you mean the position resolution will grow arbitrarily large?
>
> I meant what I said. If you make the detector smaller, its position
> resolution gets smaller too -- that is, better. But beyond a certain
> point, which in practice is usually well above the Heisenberg limit,
> making it smaller makes its momentum resolution larger.
>
>
> Tom Roberts ***@lucent.com

This has little to do with the HUP. It has to do with trying to extract
velocity/momentum informattion at near QM scales using naive methods,
like for instance position differentiation. The reason is the error
accumulation due to differentiation, nothing related to HUP.

I think HUP is a much fundamental claim about the natiure of physical
reality according to orthodox QM interpretation. Making any claims
about HUP holding based on the inability to extract state information
is a logical non sequitur.

Needless to say that QM computing will soon present a challenge to HUP
validity as any measurement errors will be decreased dramatically using
such technology.

So it is the computational error, not the resolution of the detector at
small scales that affects its performance. Resolution applies to the
quantity mesured directly, like position in the case of a linear or
rotary decoder, and error applies in the case of any deduced quantities
like velocity/momentum.

HUP is something different, but there are at least three competing
interpretations at the moment of what it means.

Mike
Gregory L. Hansen
2005-08-06 15:12:21 UTC
Permalink
In article <***@g49g2000cwa.googlegroups.com>,
<***@gmail.com> wrote:
>
>kenseto wrote:
>> > > Doesn't that violate the Uncertainty Principle?
>> >
>> > No.
>>
>> Why not?...you know the path, the speed and the position of a single photon
>> from birth to detection. Why isn't that a violation of the UP?
>
>
>Heiseinberg's uncertainty applies only to predictive measurements.

A diffracting grating with smaller spacing makes Bragg peaks that are
farther apart because reducing the spacings increases transverse momentum
of the interacting particles. An atom has size because the electron has
fallen as far into the nucleus as the uncertainty principle will let it
go, and it's a nucleus surrounded by an electron cloud rather than an
electron surrounded by a nuclear cloud because p=mv-- the larger particle
has a better defined position.

The uncertainty principle doesn't turn off just because we're not looking.
--
"What's another word for thesaurus?" -- Steven Wright

"Let me look in my synonymicon." -- Thaddeus Stout
s***@gmail.com
2005-08-06 18:42:32 UTC
Permalink
Gregory L. Hansen wrote:
> In article <***@g49g2000cwa.googlegroups.com>,
> <***@gmail.com> wrote:
> >
> >kenseto wrote:
> >> > > Doesn't that violate the Uncertainty Principle?
> >> >
> >> > No.
> >>
> >> Why not?...you know the path, the speed and the position of a single photon
> >> from birth to detection. Why isn't that a violation of the UP?
> >
> >
> >Heiseinberg's uncertainty applies only to predictive measurements.
>
> A diffracting grating with smaller spacing makes Bragg peaks that are
> farther apart because reducing the spacings increases transverse momentum
> of the interacting particles. An atom has size because the electron has
> fallen as far into the nucleus as the uncertainty principle will let it
> go, and it's a nucleus surrounded by an electron cloud rather than an
> electron surrounded by a nuclear cloud because p=mv-- the larger particle
> has a better defined position.
>
> The uncertainty principle doesn't turn off just because we're not looking.

You didn't read what I said then proceeded to draw inferences all wrong
and finished off with a sequence of irrelevant statements.

The uncertainty principle does not prohibit the arbitrarily precise
knowledge of a systems historical state. It only applies to predictions
from an initial state. This is basic stuff.



> --
> "What's another word for thesaurus?" -- Steven Wright
>
> "Let me look in my synonymicon." -- Thaddeus Stout
Tom Roberts
2005-08-06 19:37:36 UTC
Permalink
***@gmail.com wrote:
> The uncertainty principle does not prohibit the arbitrarily precise
> knowledge of a systems historical state.

This is plain and simply not true.


> It only applies to predictions
> from an initial state.

It is not possible to know the values of conjugate variables precisely,
for any system. Whether or not "future" and "past" (or your "prediction"
and "initial state") apply to that depends on the variables and the
system involved....


> This is basic stuff.

Yes, it is. But you got it wrong.


Tom Roberts ***@lucent.com
s***@gmail.com
2005-08-07 08:15:32 UTC
Permalink
Tom Roberts wrote:
> ***@gmail.com wrote:
> > The uncertainty principle does not prohibit the arbitrarily precise
> > knowledge of a systems historical state.
>
> This is plain and simply not true.
>
>
> > It only applies to predictions
> > from an initial state.
>
> It is not possible to know the values of conjugate variables precisely,
> for any system. Whether or not "future" and "past" (or your "prediction"
> and "initial state") apply to that depends on the variables and the
> system involved....
>
>
> > This is basic stuff.
>
> Yes, it is. But you got it wrong.
>
>
> Tom Roberts ***@lucent.com

Feynman remarks about this point in one of his lectures (volume 3). I
don't care to discuss this anymore with you, since i'm trivially right.
Gregory L. Hansen
2005-08-06 19:54:03 UTC
Permalink
In article <***@z14g2000cwz.googlegroups.com>,
<***@gmail.com> wrote:
>
>Gregory L. Hansen wrote:
>> In article <***@g49g2000cwa.googlegroups.com>,
>> <***@gmail.com> wrote:
>> >
>> >kenseto wrote:
>> >> > > Doesn't that violate the Uncertainty Principle?
>> >> >
>> >> > No.
>> >>
>> >> Why not?...you know the path, the speed and the position of a single photon
>> >> from birth to detection. Why isn't that a violation of the UP?
>> >
>> >
>> >Heiseinberg's uncertainty applies only to predictive measurements.
>>
>> A diffracting grating with smaller spacing makes Bragg peaks that are
>> farther apart because reducing the spacings increases transverse momentum
>> of the interacting particles. An atom has size because the electron has
>> fallen as far into the nucleus as the uncertainty principle will let it
>> go, and it's a nucleus surrounded by an electron cloud rather than an
>> electron surrounded by a nuclear cloud because p=mv-- the larger particle
>> has a better defined position.
>>
>> The uncertainty principle doesn't turn off just because we're not looking.
>
>You didn't read what I said then proceeded to draw inferences all wrong
>and finished off with a sequence of irrelevant statements.
>
>The uncertainty principle does not prohibit the arbitrarily precise
>knowledge of a systems historical state. It only applies to predictions
>from an initial state. This is basic stuff.

Oh, right, historical state. Slit with these dimensions, photon was
detected right there. And going from a wavefunction to a detection event
is something the philosophers are still arguing about.


--
"Pain is temporary, quitting lasts forever" -- Lance Armstrong
s***@gmail.com
2005-08-08 14:20:08 UTC
Permalink
Gregory L. Hansen wrote:
> In article <***@z14g2000cwz.googlegroups.com>,
> <***@gmail.com> wrote:
> >
> >Gregory L. Hansen wrote:
> >> In article <***@g49g2000cwa.googlegroups.com>,
> >> <***@gmail.com> wrote:
> >> >
> >> >kenseto wrote:
> >> >> > > Doesn't that violate the Uncertainty Principle?
> >> >> >
> >> >> > No.
> >> >>
> >> >> Why not?...you know the path, the speed and the position of a single photon
> >> >> from birth to detection. Why isn't that a violation of the UP?
> >> >
> >> >
> >> >Heiseinberg's uncertainty applies only to predictive measurements.
> >>
> >> A diffracting grating with smaller spacing makes Bragg peaks that are
> >> farther apart because reducing the spacings increases transverse momentum
> >> of the interacting particles. An atom has size because the electron has
> >> fallen as far into the nucleus as the uncertainty principle will let it
> >> go, and it's a nucleus surrounded by an electron cloud rather than an
> >> electron surrounded by a nuclear cloud because p=mv-- the larger particle
> >> has a better defined position.
> >>
> >> The uncertainty principle doesn't turn off just because we're not looking.
> >
> >You didn't read what I said then proceeded to draw inferences all wrong
> >and finished off with a sequence of irrelevant statements.
> >
> >The uncertainty principle does not prohibit the arbitrarily precise
> >knowledge of a systems historical state. It only applies to predictions
> >from an initial state. This is basic stuff.
>
> Oh, right, historical state. Slit with these dimensions, photon was
> detected right there. And going from a wavefunction to a detection event
> is something the philosophers are still arguing about.

You can deduce the precise historical state of a quantum mechanical
system without having measured it in the past. Just look at the feynman
integral. Going from a PRECISE state A to PRECISE state B has
probability of simply adding the amplitude of every possible path
(varing the complex phase of that amplitude by the action of that path)
and then simplying squaring the result.

This is why it's important to UNDERSTAND what it is QM is saying, as
opposed to just rote learning the mathematical formulation and passing
those abstract mathematical tools as physics.



>
> --
> "Pain is temporary, quitting lasts forever" -- Lance Armstrong
s***@gmail.com
2005-08-08 14:24:13 UTC
Permalink
***@gmail.com wrote:
> You can deduce the precise historical state of a quantum mechanical
> system without having measured it in the past. Just look at the feynman
> integral. Going from a PRECISE state A to PRECISE state B has
> probability of simply adding the amplitude of every possible path
> (varing the complex phase of that amplitude by the action of that path)
> and then simplying squaring the result.

squaring the absolute value of that result, rather.

>
> This is why it's important to UNDERSTAND what it is QM is saying, as
> opposed to just rote learning the mathematical formulation and passing
> those abstract mathematical tools as physics.
>
>
>
> >
> > --
> > "Pain is temporary, quitting lasts forever" -- Lance Armstrong
Tom Roberts
2005-08-08 17:50:44 UTC
Permalink
***@gmail.com wrote:
> You can deduce the precise historical state of a quantum mechanical
> system without having measured it in the past. Just look at the feynman
> integral. Going from a PRECISE state A to PRECISE state B has
> probability of simply adding the amplitude of every possible path
> (varing the complex phase of that amplitude by the action of that path)
> and then simplying squaring the result.

Not true -- this is woefully insufficient to deduce a "precise
historical state". While indeed the integral over paths from A to B is
well defined, this only lets you deduce historical state A when A->B is
the only nonzero such integral (i.e. there exists no state A' for which
the integral from A' to B is nonzero). This presumes you know B (which
is also problematical...).

And this presumes the existence of "precise state A". For instance the
wavefunction of a particle in state A at time tA could include
delta^3(x-x0) for a constant 3-vector x0, and you would have a precise
state in position x (a 3-vector); but the momentum of the particle would
be completely unknown -- not very "precise", is it? Specifically: any
later measurement of the particle's position would give no information
at all about the value of x0.

And there is also the problem of at what time your "history" is to be
taken, because in general state A does not include a unique,
well-defined time. This depends on the nature of the system, of course.


Tom Roberts ***@lucent.com
Schoenfeld
2005-08-09 04:28:37 UTC
Permalink
Tom Roberts wrote:
> ***@gmail.com wrote:
> > You can deduce the precise historical state of a quantum mechanical
> > system without having measured it in the past. Just look at the feynman
> > integral. Going from a PRECISE state A to PRECISE state B has
> > probability of simply adding the amplitude of every possible path
> > (varing the complex phase of that amplitude by the action of that path)
> > and then simplying squaring the result.
>
> Not true -- this is woefully insufficient to deduce a "precise
> historical state". While indeed the integral over paths from A to B is
> well defined, this only lets you deduce historical state A when A->B is
> the only nonzero such integral (i.e. there exists no state A' for which
> the integral from A' to B is nonzero). This presumes you know B (which
> is also problematical...).

It doesn't. Feynman remarks about this point (on my side) in one of his
volume 3 lectures which I can't be bothered to track down. Your
argument is AT BEST a matter of INTERPRETATION but strictly there is
nothing prohibiting the precise knowledge of a systems conjugate
variables in the past. If I recall correctly feynman talks about a
photon going through a slit and deducing precisely the
momentum-position of the photon at some point in time in the past but
this doesnt violate HUP since HUP applies to the ability to predict.

> And this presumes the existence of "precise state A".

Which is a much more reasonable assumption than otherwise. QM does not
prohibit the existence of precise states. You NEED PRECISE STATES to
recover causality. This is achieved by COLLAPSE OF THE STATE VECTOR.




> For instance the
> wavefunction of a particle in state A at time tA could include
> delta^3(x-x0) for a constant 3-vector x0, and you would have a precise
> state in position x (a 3-vector); but the momentum of the particle would
> be completely unknown -- not very "precise", is it?

A woefully lacking proof. Your argument is that the state vector never
collapses, which is trivially false both empirically and
"theoretically".

Open Schroedingers box and the cat is either precisely dead or
precisely alive, not a superposition of one the other or both.
the softrat
2005-08-09 05:48:49 UTC
Permalink
On 8 Aug 2005 21:28:37 -0700, "Schoenfeld" <***@gmail.com>
wrote:
>
>Open Schroedingers box and the cat is either precisely dead or
>precisely alive, not a superposition of one the other or both.

No, no, no!

The cat is half-dead and half-alive due to a lack of food and water!

Not to mention cat litter.....


the softrat
Sometimes I get so tired of the taste of my own toes.
mailto:***@pobox.com
--
No matter where you go, there you are
Tom Roberts
2005-08-10 01:38:34 UTC
Permalink
Schoenfeld wrote:
> Feynman remarks about this point (on my side) in one of his
> volume 3 lectures which I can't be bothered to track down. Your
> argument is AT BEST a matter of INTERPRETATION but strictly there is
> nothing prohibiting the precise knowledge of a systems conjugate
> variables in the past. If I recall correctly feynman talks about a
> photon going through a slit and deducing precisely the
> momentum-position of the photon at some point in time in the past but
> this doesnt violate HUP since HUP applies to the ability to predict.

You really should either look up this passage, or stop writing about
this. Your recollections are WRONG.


> You NEED PRECISE STATES to
> recover causality. This is achieved by COLLAPSE OF THE STATE VECTOR.

Nonsense. To both. Collapse of the state vector is just the Cophenhagen
interpretation of quantum mechanics....


>>For instance the
>>wavefunction of a particle in state A at time tA could include
>>delta^3(x-x0) for a constant 3-vector x0, and you would have a precise
>>state in position x (a 3-vector); but the momentum of the particle would
>>be completely unknown -- not very "precise", is it?
>
> Your argument is that the state vector never
> collapses, which is trivially false both empirically and
> "theoretically".

No. My point is that conjugate variables INHERENTLY cannot be known
precisely for a given system. This is a direct and inherent property of
Fourier transforms. <shrug>


Tom Roberts ***@lucent.com
s***@gmail.com
2005-08-10 02:28:32 UTC
Permalink
Tom Roberts wrote:
> Schoenfeld wrote:
> > Feynman remarks about this point (on my side) in one of his
> > volume 3 lectures which I can't be bothered to track down. Your
> > argument is AT BEST a matter of INTERPRETATION but strictly there is
> > nothing prohibiting the precise knowledge of a systems conjugate
> > variables in the past. If I recall correctly feynman talks about a
> > photon going through a slit and deducing precisely the
> > momentum-position of the photon at some point in time in the past but
> > this doesnt violate HUP since HUP applies to the ability to predict.
>
> You really should either look up this passage, or stop writing about
> this. Your recollections are WRONG.

My recollection is not wrong, you are wrong. Here is the quote:

"Sometimes people say quantum mechanics is all wrong. When the particle
arrived from the left, it's vertical momentum was zero**. And now that
it has gone through the slit, it's position is known. Both position and
momentum seem to be known with arbitrary accuracy.

It is quite true that we can receive a particle, and on reception
determine what its position is and its momentum would have had to have
been to have gotten there. That is true, but that is not what the
uncertainty [principle] refers to. The [uncertainty principle] refers
to the predictability of a situation, not remarks about the past."
Feynman Lectures Volume 3 chapter 2 section 2-2.

**: he is talking about a particle emitted from far distance, thus the
further away it is the less the verticle momentum it must have to pass
through the single slit:


Repeat: you need not apply a measurement to a system in order to
determine it's current state in the future. Due to this, you can know
the current state in the future with arbitrary precision (but it's
useless information since you cannot use it to predict anything).


> >>For instance the
> >>wavefunction of a particle in state A at time tA could include
> >>delta^3(x-x0) for a constant 3-vector x0, and you would have a precise
> >>state in position x (a 3-vector); but the momentum of the particle would
> >>be completely unknown -- not very "precise", is it?
> >
> > Your argument is that the state vector never
> > collapses, which is trivially false both empirically and
> > "theoretically".
>
> No. My point is that conjugate variables INHERENTLY cannot be known
> precisely for a given system. This is a direct and inherent property of
> Fourier transforms. <shrug>

That is NOT true. It is possible to know the historical conjugate
variables of a system with arbitrary precision.



>
> Tom Roberts ***@lucent.com
Matthew Lybanon
2005-08-10 03:40:16 UTC
Permalink
First, the quotation is from "The Feynman Lectures . . ." Volume 3, chapter
38, section 38.2. Second, Feynman did not use "it's" where he meant "its."
Third, your math is no better than your English.
Schoenfeld
2005-08-10 05:17:18 UTC
Permalink
Matthew Lybanon wrote:
> First, the quotation is from "The Feynman Lectures . . ."

Nice counter argument, idiot.

> Volume 3, chapter
> 38, section 38.2.

Actually, troll, it is Volume 3, Chapter 2, Section 2-2. Learn to read.

> Second, Feynman did not use "it's" where he meant "its."

You've got nothing.

> Third, your math is no better than your English.

Read it and grovel, moron.

"Sometimes people say quantum mechanics is all wrong. When the particle
arrived from the left, it's vertical momentum was zero**. And now that
it has gone through the slit, it's position is known. Both position and
momentum seem to be known with arbitrary accuracy.It is quite true that
we can receive a particle, and on reception determine what its position
is and its momentum would have had to have been to have gotten there.
That is true, but that is not what the uncertainty [principle] refers
to. The [uncertainty principle] refers to the predictability of a
situation, not remarks about the past." Feynman Lectures Volume 3
chapter 2 section 2-2.
Bilge
2005-08-10 22:31:11 UTC
Permalink
schoenfelch, misinterprets another one:
>
>Tom Roberts wrote:
>> Schoenfeld wrote:
>> > Feynman remarks about this point (on my side) in one of his
>> > volume 3 lectures which I can't be bothered to track down. Your
>> > argument is AT BEST a matter of INTERPRETATION but strictly there is
>> > nothing prohibiting the precise knowledge of a systems conjugate
>> > variables in the past. If I recall correctly feynman talks about a
>> > photon going through a slit and deducing precisely the
>> > momentum-position of the photon at some point in time in the past but
>> > this doesnt violate HUP since HUP applies to the ability to predict.
>>
>> You really should either look up this passage, or stop writing about
>> this. Your recollections are WRONG.
>
>My recollection is not wrong, you are wrong. Here is the quote:

Then, your understanding of your recollection is wrong.

>"Sometimes people say quantum mechanics is all wrong. When the particle
>arrived from the left, it's vertical momentum was zero**.

Note the word ``was.''

>And now that it has gone through the slit, it's position is known.
>Both position and momentum seem to be known with arbitrary accuracy.

Obviously, feynman does not say the position and momentum are known
simultaneously, even in your bizarre notion of knowing these things
historically. The vertical momentum is well-defined entering the slit.
(Recall the word ``was'').

The slit performs a position measuremet, leaving the vertical momentum
indeterminate. The vertical position and vertical momentum are not known
simultaneously. Feynman does not say that it is. If that weren't the case,
you wouldn't get a diffraction pattern.

>It is quite true that we can receive a particle, and on reception
>determine what its position is and its momentum would have had to have
>been to have gotten there. That is true, but that is not what the
>uncertainty [principle] refers to. The [uncertainty principle] refers
>to the predictability of a situation, not remarks about the past."
>Feynman Lectures Volume 3 chapter 2 section 2-2.

Which only indicates you were (and still are mistaken).
Note that knowing the momentum before it reaches the slit
is perfectly allowed. Once the position measurement is
performed (i.e., the particle enters the slit), the
vertical momentum, which is canonically conjugate to
the vertical position, is not well-defined. It doesn't
get any better defined with age.

>**: he is talking about a particle emitted from far distance, thus the
>further away it is the less the verticle momentum it must have to pass
>through the single slit:

>Repeat: you need not apply a measurement to a system in order to
>determine it's current state in the future. Due to this, you can know
>the current state in the future with arbitrary precision (but it's
>useless information since you cannot use it to predict anything).

In other words, you are rejecting the results of the epr experiment.

>> >>For instance the
>> >>wavefunction of a particle in state A at time tA could include
>> >>delta^3(x-x0) for a constant 3-vector x0, and you would have a precise
>> >>state in position x (a 3-vector); but the momentum of the particle would
>> >>be completely unknown -- not very "precise", is it?
>> >
>> > Your argument is that the state vector never
>> > collapses, which is trivially false both empirically and
>> > "theoretically".
>>
>> No. My point is that conjugate variables INHERENTLY cannot be known
>> precisely for a given system. This is a direct and inherent property of
>> Fourier transforms. <shrug>
>
>That is NOT true. It is possible to know the historical conjugate
>variables of a system with arbitrary precision.

No, it isn't and feynman did not say that it is possible.
s***@gmail.com
2005-08-14 10:04:22 UTC
Permalink
Bilge wrote:
> schoenfelch, misinterprets another one:

Please refrain from further homosexual advances.

> >
> >Tom Roberts wrote:
> >> Schoenfeld wrote:
> >> > Feynman remarks about this point (on my side) in one of his
> >> > volume 3 lectures which I can't be bothered to track down. Your
> >> > argument is AT BEST a matter of INTERPRETATION but strictly there is
> >> > nothing prohibiting the precise knowledge of a systems conjugate
> >> > variables in the past. If I recall correctly feynman talks about a
> >> > photon going through a slit and deducing precisely the
> >> > momentum-position of the photon at some point in time in the past but
> >> > this doesnt violate HUP since HUP applies to the ability to predict.
> >>
> >> You really should either look up this passage, or stop writing about
> >> this. Your recollections are WRONG.
> >
> >My recollection is not wrong, you are wrong. Here is the quote:
>
> Then, your understanding of your recollection is wrong.

No, you either deliberately obfuscate or unknowingly misunderstand.

> >"Sometimes people say quantum mechanics is all wrong. When the particle
> >arrived from the left, it's vertical momentum was zero**.
>
> Note the word ``was.''

Yes it was 0 until it was DETECTED. Entering the slit does not change
it's vertical momentum.

> >And now that it has gone through the slit, it's position is known.
> >Both position and momentum seem to be known with arbitrary accuracy.
>
> Obviously, feynman does not say the position and momentum are known
> simultaneously, even in your bizarre notion of knowing these things
> historically. The vertical momentum is well-defined entering the slit.
> (Recall the word ``was'').

The electrons vertical momentum is arbitrarily precise before and AFTER
it entered the slit as the slit does not disturb the electron state in
anyway.

> The slit performs a position measuremet,

That is an elementary error. The slit does NOT perform a measurement,
the slit does NOT disturb the electorn state. The slit is nothing but
mere empty space.

> leaving the vertical momentum
> indeterminate.

Empty space cannot disturb the state of an electron, for if it did
Quantum Mechanics, Classical Mechanics and Relativity would be all
wrong.

> The vertical position and vertical momentum are not known
> simultaneously. Feynman does not say that it is. If that weren't the case,
> you wouldn't get a diffraction pattern.

That's not what I said and that's not what Feynman said. I am simply
saying that AFTER detecting the electron on the plate you can deduce
the arbitrarily precise momentum/position the electron must have had at
SOME TIME T in the PAST.

hint: T is the time it is in the slit.

hint2: You can't know T before or at T.


> >It is quite true that we can receive a particle, and on reception
> >determine what its position is and its momentum would have had to have
> >been to have gotten there. That is true, but that is not what the
> >uncertainty [principle] refers to. The [uncertainty principle] refers
> >to the predictability of a situation, not remarks about the past."
> >Feynman Lectures Volume 3 chapter 2 section 2-2.
>
> Which only indicates you were (and still are mistaken).
> Note that knowing the momentum before it reaches the slit
> is perfectly allowed. Once the position measurement is
> performed (i.e., the particle enters the slit), the
> vertical momentum, which is canonically conjugate to
> the vertical position, is not well-defined. It doesn't
> get any better defined with age.

Complete nonsense. The slit does NOT apply any measurement.


> >**: he is talking about a particle emitted from far distance, thus the
> >further away it is the less the verticle momentum it must have to pass
> >through the single slit:
>
> >Repeat: you need not apply a measurement to a system in order to
> >determine it's current state in the future. Due to this, you can know
> >the current state in the future with arbitrary precision (but it's
> >useless information since you cannot use it to predict anything).
>
> In other words, you are rejecting the results of the epr experiment.

No, you just FAIL to understand Quantum Mechanics.


> >That is NOT true. It is possible to know the historical conjugate
> >variables of a system with arbitrary precision.
>
> No, it isn't and feynman did not say that it is possible.

You misread and then misspoke.

The Feynman Lectures Volume 3 chapter 2 section 2-2:
"It is quite true that we can receive a particle, and on reception
determine what its position is and its momentum would have had to have
been to have gotten there*. That is true, but that is not what the
uncertainty principle refers to. The uncertainty principle refers to
the predictability of a situation, not remarks about the past**."

*: 'there' means the measurement event (hint: the plate, not the slit).
**: exactly what I've been saying all along.
Tom Roberts
2005-08-14 15:26:28 UTC
Permalink
***@gmail.com wrote:
> Entering the slit does not change
> it's vertical momentum.

This is QUANTUM MECHANICS, and the slit most definitely DOES affect its
vertical momentum -- how else do you think a diffraction pattern arises?

In the region before entering the slit the particles are in a state with
sharp vertical momentum, but in the region after the slit the state no
longer has a sharp vertical momentum. <shrug>


> The electrons vertical momentum is arbitrarily precise before and AFTER
> it entered the slit as the slit does not disturb the electron state in
> anyway.

Not true. DEMONSTRABLY not true, as there is ALWAYS a diffraction
pattern after the slit. This is QUANTUM MECHANICS. <shrug>


> The slit does NOT perform a measurement,

Sure it does. After "passing through the slit" the vertical position of
the electron is known to higher accuracy than before it did so. This
value is not sharp, but still this is a measurement in any usual sense
of the term.


> the slit does NOT disturb the electorn state. The slit is nothing but
> mere empty space.

No. The slit is a region of empty space surrounded by opaque material.
On atomic scales you cannot truly distinguish between space and
material, of course. This is QUANTUM MECHANICS and the particles that
exit out the back have interacted with every charged particle of every
atom in that material[#], and the only reason some come out at all is
there is a tremendous cancellation because most of the charged particles
and atoms in the material have counterparts on the other side of the
slit to cancel their contribution[@]; but the edges of the slit are
irregular, and atoms there do not have exact counterparts -- ultimately
that is a major contribution to the uncertainty in the particles'
momentum and position as they come out the back (in addition there is
the underlying statistical nature of charged particle interactions).

Note I did not say "exits the slit", because its actual
trajectory is unknown. More accurately, the state of the
particles after the slit is sharp in neither position
nor momentum: the uncertainty in (vertical) position is
always larger than the slit is high, and the uncertainty
in (vertical) momentum depends roughly reciprocally on
the height of the slit.

[#] C.f. Feynman's integral over all possible paths.

[@] On the order of Avogadro's number, vastly larger
than the number of atoms missing to form the slit.


> [... further elaboration of this basic error]


You seem to have a mental picture of "little cannonballs" flying through
a slit that has definite "walls" so the "cannonballs" either hit the
"walls" and stop, or sail right through. In the macroscopic world that
sort of picture is valid to incredibly high accuracy; in the quantum
world it is JUST PLAIN WRONG.


Tom Roberts ***@lucent.com
s***@gmail.com
2005-08-14 22:41:55 UTC
Permalink
Tom Roberts wrote:
> ***@gmail.com wrote:
> > Entering the slit does not change
> > it's vertical momentum.
>
> This is QUANTUM MECHANICS, and the slit most definitely DOES affect its
> vertical momentum

You are implying that the incoming particle exchanges momentum with the
slit edges. Unless you can show how such an interaction is mediated,
then that's just nonsense. The slit cannot disturb the electron state
as the slit consists of empty space.


> -- how else do you think a diffraction pattern arises?

Well for starters, if you knew which slit the particle went through you
don't get any diffraction pattern AT ALL. Thus the diffraction pattern
arises as a consequence of not knowing which of the two slits it went
through. After measuring one of the electrons you can start to deduce
the path it necessarily must have taken to have gotten there, but this
information is not of predictive quality.

> In the region before entering the slit the particles are in a state with
> sharp vertical momentum, but in the region after the slit the state no
> longer has a sharp vertical momentum. <shrug>

How much momentum do the slit edges end up with after the partcle has
passed through? How was this energy exchange mediated?

>
> > The electrons vertical momentum is arbitrarily precise before and AFTER
> > it entered the slit as the slit does not disturb the electron state in
> > anyway.
>
> Not true. DEMONSTRABLY not true, as there is ALWAYS a diffraction
> pattern after the slit. This is QUANTUM MECHANICS. <shrug>

That's just plain wrong. If you illuminate the slits to try to see
which slit the particle went through you get NO diffraction.

>
> > The slit does NOT perform a measurement,
>
> Sure it does.

Please elaborate on the momentum exchange mechanism between slit and
particle.

>After "passing through the slit" the vertical position of
> the electron is known to higher accuracy than before it did so. This
> value is not sharp, but still this is a measurement in any usual sense
> of the term.

"Any" usual sense is inadequate. A measurement disturbs the systems
state but fully conserves momentum. How do particle/slit momentum
interactions occur?

>
> > the slit does NOT disturb the electorn state. The slit is nothing but
> > mere empty space.
>
> No. The slit is a region of empty space surrounded by opaque material.
> On atomic scales you cannot truly distinguish between space and
> material, of course. This is QUANTUM MECHANICS and the particles that
> exit out the back have interacted with every charged particle of every
> atom in that material[#], and the only reason some come out at all is
> there is a tremendous cancellation because most of the charged particles
> and atoms in the material have counterparts on the other side of the
> slit to cancel their contribution[@]; but the edges of the slit are
> irregular, and atoms there do not have exact counterparts -- ultimately
> that is a major contribution to the uncertainty in the particles'
> momentum and position as they come out the back (in addition there is
> the underlying statistical nature of charged particle interactions).


Can't you address how your "particle/slit" momentum interactions occur
within the context of this simple thought experiment from Feynmans
text?

If you decide to invoke out-of-scope complications then you might as
well invoke some internal electron machinery or hidden variables to
dismiss QM altogether.

[... further out-of-scope obfuscations]

> You seem to have a mental picture of "little cannonballs" flying through
> a slit that has definite "walls" so the "cannonballs" either hit the
> "walls" and stop, or sail right through. In the macroscopic world that
> sort of picture is valid to incredibly high accuracy; in the quantum
> world it is JUST PLAIN WRONG.

There is nothing wrong with this "mental picture" at all so long as you
consider teleological statements with probability, not certainty.

The sum over histories formulations says that the particle IS a little
cannon ball and that it ends up a little cannon ball, but the
probability of getting there is the sum of the amplitude of all
possible little cannon ball paths (varying complex phase of amplitude
by action of that path) then simply squaring absolute value of that
sum. This approach is 100% consistent with any other formulation.

>
> Tom Roberts ***@lucent.com
Tom Roberts
2005-08-15 14:26:32 UTC
Permalink
***@gmail.com wrote:
> Tom Roberts wrote:
>>***@gmail.com wrote:
>>>Entering the slit does not change
>>>it's vertical momentum.
>>This is QUANTUM MECHANICS, and the slit most definitely DOES affect its
>>vertical momentum
>
> You are implying that the incoming particle exchanges momentum with the
> slit edges. Unless you can show how such an interaction is mediated,
> then that's just nonsense. The slit cannot disturb the electron state
> as the slit consists of empty space.

You are supposed to read what I write. As I said, the EDGES of the slit
are not empty space, and the EDGES of the slit and the material outside
the edges most definitely do interact with the electrons that "pass
through" the slit. These interactions affect the vertical component of
momentum of the electron. <shrug>


>>-- how else do you think a diffraction pattern arises?
>
> Well for starters, if you knew which slit the particle went through you
> don't get any diffraction pattern AT ALL.

Stick to THIS discussion. There is a single slit. And there _is_ a
diffraction pattern.

For a multi-slit experiment in which one knows which
slit the particles went through, there _IS_ a diffraction
pattern, it's just a single-slit pattern instead of the
multi-slit pattern. Note this assumes that obtaining the
knowledge of "which slit" does not perturb the system any
more than obtaining that knowledge requires.

You _REALLY_ need to learn basic quantum mechanics before attempting to
discuss it.



> After measuring one of the electrons you can start to deduce
> the path it necessarily must have taken to have gotten there [...]

This is not possible -- C.f.Feynman's integral over all possible paths
-- there is no "path it necessarily must have taken to have gotten
there", there are many different possible paths (with different
amplitudes for each).

I repeat: this is QUANTUM MECHANICS. For an electron observed
after the material containing the slit, there is nonzero
probability that it tunneled through the material and "missed"
the slit entirely. You do not, and CAN NOT know over which
path any given electron traveled, THIS IS QUANTUM MECHANICS --
you cannot know what you don't measure (and making measurements
perturbs the system being measured).

You _REALLY_ need to learn basic quantum mechanics before attempting to
discuss it.


>>In the region before entering the slit the particles are in a state with
>>sharp vertical momentum, but in the region after the slit the state no
>>longer has a sharp vertical momentum. <shrug>
>
> How much momentum do the slit edges end up with after the partcle has
> passed through? How was this energy exchange mediated?

How much is variable, and not sharp. This is mediated by electromagnetic
interactions between the electron and ALL of the charged particles in
the material surrounding the slit. Please go back and actually READ what
I wrote. And go READ a textbook on quantum mechanics, as you quite
clearly do not understand the subject.


>>>The electrons vertical momentum is arbitrarily precise before and AFTER
>>>it entered the slit as the slit does not disturb the electron state in
>>>anyway.
>>Not true. DEMONSTRABLY not true, as there is ALWAYS a diffraction
>>pattern after the slit. This is QUANTUM MECHANICS. <shrug>
>
> That's just plain wrong. If you illuminate the slits to try to see
> which slit the particle went through you get NO diffraction.

A. There has been only one slit in thie discussion.
B. For a single slit there is indeed a diffraction pattern -- this
is QUANTUM MECHANICS.


> Please elaborate on the momentum exchange mechanism between slit and
> particle.

Electromagnetic interations between the electron and ALL charged
particles in the material surrounding the slit.


>>You seem to have a mental picture of "little cannonballs" flying through
>>a slit that has definite "walls" so the "cannonballs" either hit the
>>"walls" and stop, or sail right through. In the macroscopic world that
>>sort of picture is valid to incredibly high accuracy; in the quantum
>>world it is JUST PLAIN WRONG.
>
> There is nothing wrong with this "mental picture" at all so long as you
> consider teleological statements with probability, not certainty.

Not true. That picture is just plain wrong in the quantum realm.
Electrons simply do NOT behave like "little cannonballs". <shrug>


> The sum over histories formulations says that the particle IS a little
> cannon ball [...]

Not true. You _REALLY_ need to learn basic quantum mechanics before
attempting to discuss it.


[This is going nowhere. Don't expect me to re-repeat myself
until you have actually LEARNED something about the subject.
Your errors and misconceptions are about the very foundations
of QM.]


Tom Roberts ***@lucent.com
Schoenfeld
2005-08-15 15:48:48 UTC
Permalink
Tom Roberts wrote:
> ***@gmail.com wrote:
> > Tom Roberts wrote:
> >>***@gmail.com wrote:
> >>>Entering the slit does not change
> >>>it's vertical momentum.
> >>This is QUANTUM MECHANICS, and the slit most definitely DOES affect its
> >>vertical momentum
> >
> > You are implying that the incoming particle exchanges momentum with the
> > slit edges. Unless you can show how such an interaction is mediated,
> > then that's just nonsense. The slit cannot disturb the electron state
> > as the slit consists of empty space.
>
> You are supposed to read what I write. As I said, the EDGES of the slit
> are not empty space, and the EDGES of the slit and the material outside
> the edges most definitely do interact with the electrons that "pass
> through" the slit. These interactions affect the vertical component of
> momentum of the electron. <shrug>

What you said was all wrong. This is a thought experiment and you can
assume all apparatus material is 100% opaque (note: what a silly red
herring you raise).

>
> >>-- how else do you think a diffraction pattern arises?
> >
> > Well for starters, if you knew which slit the particle went through you
> > don't get any diffraction pattern AT ALL.
>
> Stick to THIS discussion. There is a single slit. And there _is_ a
> diffraction pattern.

I did, you just misunderstood. It doesn't matter if it's n slits or 1
slit, you DON'T get interference if you know which slit the particle
entered through. That's right, to even assume that it came through the
single slit requires a position measurement and once you do that you
DON'T get any interference at all.

Repeat: To know if the particle even enters through a single slit
requires a position measurement on that particle, and once applied, you
don't get interference and the probability distribution follows the
classical analogue.

If you don't understand that then you need to re-educate yourself
rather quickly.


> For a multi-slit experiment in which one knows which
> slit the particles went through, there _IS_ a diffraction
> pattern, [...]
>
> You _REALLY_ need to learn basic quantum mechanics before attempting to
> discuss it.

That is absolutely wrong. For if it was I could form a

Proposition 1:
"The particle enters either slit 1 or slit 2"

and compute the probability distribution on the screen a priori. That
calculated distribution has NO INTERFERENCE. If you apply position
measurements on the particles before hitting screen, to know which slit
they came from, then you don't get any interference AT ALL. Don't you
know that? If you DON'T apply position measurements then you get
interference. Obviously, having the knowledge of which slit particles
entered through prevents interference completely. Acquiring this
knowledge disturbs particle state due to photon-particle momentum
exchanges (but that is only technical point).

Fundamentally, if you look at the slits then you can say particles
entered either slit 1 or 2 BUT if you don't look then don't say it
entered either slit 1 or 2.



>
>
> > After measuring one of the electrons you can start to deduce
> > the path it necessarily must have taken to have gotten there [...]
>
> This is not possible -- C.f.Feynman's integral over all possible paths
> -- there is no "path it necessarily must have taken to have gotten
> there", there are many different possible paths (with different
> amplitudes for each).
>
> I repeat: this is QUANTUM MECHANICS. For an electron observed
> after the material containing the slit, there is nonzero
> probability that it tunneled through the material and "missed"
> the slit entirely. You do not, and CAN NOT know over which
> path any given electron traveled, THIS IS QUANTUM MECHANICS --
> you cannot know what you don't measure (and making measurements
> perturbs the system being measured).
>
> You _REALLY_ need to learn basic quantum mechanics before attempting to
> discuss it.

You started off with "stick to this discussion" and now you are
invoking absurd off-topic experimental technicalities. This is a
THOUGHT experiment and you can assume the apparatus material is 100%
opaque.

Repeat, if you look at the slits then you can say particles entered
either slit 1 or 2 (no interference) BUT if you don't look then don't
say it entered either slit 1 or 2 (interference).


>
> >>In the region before entering the slit the particles are in a state with
> >>sharp vertical momentum, but in the region after the slit the state no
> >>longer has a sharp vertical momentum. <shrug>
> >
> > How much momentum do the slit edges end up with after the partcle has
> > passed through? How was this energy exchange mediated?
>
> How much is variable, and not sharp. This is mediated by electromagnetic
> interactions between the electron and ALL of the charged particles in
> the material surrounding the slit. Please go back and actually READ what
> I wrote. And go READ a textbook on quantum mechanics, as you quite
> clearly do not understand the subject.

I did read a textbook on QM, and obviously you have PROFOUND
misunderstandings on this subject.

1. You don't understand that applying position measurements on particle
prevents interference.
2. Unless you apply a position measurement, then you can't say it
enters slit 1, 2 or slit n.


[snip]

> > There is nothing wrong with this "mental picture" at all so long as you
> > consider teleological statements with probability, not certainty.
>
> Not true. That picture is just plain wrong in the quantum realm.
> Electrons simply do NOT behave like "little cannonballs". <shrug>

Can't you read? There is nothing wrong with this "mental picture" at
all so long as you consider *teleological* statements with
*probability*, not certainty.

>
> > The sum over histories formulations says that the particle IS a little
> > cannon ball [...]
>
> Not true. You _REALLY_ need to learn basic quantum mechanics before
> attempting to discuss it.

Can't you read?

The sum over histories formulation says that the particle IS a little
"cannon ball" and that it ends up a little "cannon ball", but the
probability of getting there is the sum of the amplitude of all
possible little "cannon ball" paths (varying complex phase of amplitude
by action of that path) then simply squaring absolute value of that
sum. This approach is 100% *consistent* with any other formulation.

I suspect I overestimated your capabilities in this field. Aren't you
supposed to be a post-grad?
s***@gmail.com
2005-08-17 06:34:16 UTC
Permalink
Schoenfeld wrote:
> Tom Roberts wrote:
> > ***@gmail.com wrote:
> > > Tom Roberts wrote:
> > >>***@gmail.com wrote:
> > >>>Entering the slit does not change
> > >>>it's vertical momentum.
> > >>This is QUANTUM MECHANICS, and the slit most definitely DOES affect its
> > >>vertical momentum
> > >
> > > You are implying that the incoming particle exchanges momentum with the
> > > slit edges. Unless you can show how such an interaction is mediated,
> > > then that's just nonsense. The slit cannot disturb the electron state
> > > as the slit consists of empty space.
> >
> > You are supposed to read what I write. As I said, the EDGES of the slit
> > are not empty space, and the EDGES of the slit and the material outside
> > the edges most definitely do interact with the electrons that "pass
> > through" the slit. These interactions affect the vertical component of
> > momentum of the electron. <shrug>
>
> What you said was all wrong. This is a thought experiment and you can
> assume all apparatus material is 100% opaque (note: what a silly red
> herring you raise).
>
> >
> > >>-- how else do you think a diffraction pattern arises?
> > >
> > > Well for starters, if you knew which slit the particle went through you
> > > don't get any diffraction pattern AT ALL.
> >
> > Stick to THIS discussion. There is a single slit. And there _is_ a
> > diffraction pattern.
>
> I did, you just misunderstood. It doesn't matter if it's n slits or 1
> slit, you DON'T get interference if you know which slit the particle
> entered through. That's right, to even assume that it came through the
> single slit requires a position measurement and once you do that you
> DON'T get any interference at all.
>
> Repeat: To know if the particle even enters through a single slit
> requires a position measurement on that particle, and once applied, you
> don't get interference and the probability distribution follows the
> classical analogue.

For the benefit of the lurker I've provided references to support my
points:

"If one looks at the holes, or more accurately, if one has a piece of
apparatus which is capable of determining whether the electrons go
through hole 1 or hole 2, then one can say that it goes either through
hole 1 or hole 2. But, when one does not try to tell which way the
electron goes, when there is nothing in the experiment to disturb the
electrons, then one may not say that an electron goes either through
hole 1 or hole 2."
The Feynman Lectures, Volume 3, Chapter 1, Section 1-6.


> That is absolutely wrong. For if it was I could form a
>
> Proposition 1:
> "The particle enters either slit 1 or slit 2"
>
> and compute the probability distribution on the screen a priori. That
> calculated distribution has NO INTERFERENCE. If you apply position
> measurements on the particles before hitting screen, to know which slit
> they came from, then you don't get any interference AT ALL. Don't you
> know that? If you DON'T apply position measurements then you get
> interference. Obviously, having the knowledge of which slit particles
> entered through prevents interference completely. Acquiring this
> knowledge disturbs particle state due to photon-particle momentum
> exchanges (but that is only technical point).
>
> Fundamentally, if you look at the slits then you can say particles
> entered either slit 1 or 2 BUT if you don't look then don't say it
> entered either slit 1 or 2.

"It is impossible to design an apparatus to determine which hole the
electron passes through, that will not at the same time disturb the
electrons enough to destroy the interference pattern."
The Feynman Lectures, Volume 3, Chapter 1, Section 1-6.

In fact that whole chapter pretty much makes the repeated point that
I've been making here. Sad, really.
Bilge
2005-08-22 01:00:28 UTC
Permalink
schoenfelch:
>
>Bilge wrote:
>> schoenfelch, misinterprets another one:
>
>Please refrain from further homosexual advances.

You've confused this newsgroup for the one you use for your
social activities. I said you were an idiot because you are an
idiot, not because I was trying to be nice. While calling you
an idiot might be the nicest thing anyone has ever said to you,
you're out of luck. Look somewhere else to satisfy your fetishes.

[*mindless rambling snipped*]
>*: 'there' means the measurement event (hint: the plate, not the slit).
>**: exactly what I've been saying all along.

You are still an idiot.
Tom Roberts
2005-08-11 00:27:39 UTC
Permalink
***@gmail.com wrote:
> Tom Roberts wrote:
>>You really should either look up this passage, or stop writing about
>>this. Your recollections are WRONG.
>
> My recollection is not wrong, [...]

Yes it is, and your quote proves it. <shrug>


> Here is the quote:
> "Sometimes people say quantum mechanics is all wrong. When the particle
> arrived from the left, it's vertical momentum was zero**. And now that
> it has gone through the slit, it's position is known. Both position and
> momentum seem to be known with arbitrary accuracy.

Feynman was writing with a clarity and precision that you lack. He says
its vertical momentum _WAS_ zero when it arrived from the left, but he
says nothing at all about its vertical momentum AFTER it goes through
the slit. He says its position is known AFTER it has gone through the
slit, but says nothing about its position BEFORE going through. And he
says both position and momentum SEEM to be known with arbitrary
accuracy, but he never says that they ARE. In fact, his subsequent
discussion explores that "SEEMS" and shows that indeed they never are
(and never were!) known SIMULTANEOUSLY -- we knew its momentum BEFORE it
went through the slit and we know its position immediately AFTER it goes
through. <shrug>


Tom Roberts ***@lucent.com
Schoenfeld
2005-08-11 01:18:08 UTC
Permalink
Tom Roberts wrote:
> ***@gmail.com wrote:
> > Tom Roberts wrote:
> >>You really should either look up this passage, or stop writing about
> >>this. Your recollections are WRONG.
> >
> > My recollection is not wrong, [...]
>
> Yes it is, and your quote proves it. <shrug>

ROTFL!

>
> > Here is the quote:
> > "Sometimes people say quantum mechanics is all wrong. When the particle
> > arrived from the left, it's vertical momentum was zero**. And now that
> > it has gone through the slit, it's position is known. Both position and
> > momentum seem to be known with arbitrary accuracy.
>
> Feynman was writing with a clarity and precision that you lack. He says
> its vertical momentum _WAS_ zero when it arrived from the left, but he
> says nothing at all about its vertical momentum AFTER it goes through
> the slit. He says its position is known AFTER it has gone through the
> slit, but says nothing about its position BEFORE going through. And he
> says both position and momentum SEEM to be known with arbitrary
> accuracy, but he never says that they ARE. In fact, his subsequent

Let me refresh your faulty memory:

I SAID:
"Heiseinberg's uncertainty applies only to predictive measurements.
There is nothing preventing you from knowing where a photon was and how
much momentum it had with arbitrary certainty. "

YOU SAID:
"It is not possible to know the values of conjugate variables
precisely,
for any system. Whether or not "future" and "past" (or your
"prediction"
and "initial state") apply to that depends on the variables and the
system involved.... "



> discussion explores that "SEEMS" and shows that indeed they never are
> (and never were!) known SIMULTANEOUSLY -- we knew its momentum BEFORE it
> went through the slit and we know its position immediately AFTER it goes
> through. <shrug>

Hint: he ALWAYS knew the momentum WITHOUT MEASUREMENT and this was my
point all along. This was the point you disagreed with all along
(except now that you've changed your tune rather dramatically).

I'll leave you with another of your blunders:

----
> The uncertainty principle does not prohibit the arbitrarily precise
> knowledge of a systems historical state.

This is plain and simply not true.
----

>
> Tom Roberts ***@lucent.com
Androcles
2005-08-11 01:28:01 UTC
Permalink
"Schoenfeld" <***@gmail.com> wrote in message
news:***@g43g2000cwa.googlegroups.com...
|
| Tom Roberts wrote:
| > ***@gmail.com wrote:
| > > Tom Roberts wrote:
| > >>You really should either look up this passage, or stop writing
about
| > >>this. Your recollections are WRONG.
| > >
| > > My recollection is not wrong, [...]
| >
| > Yes it is, and your quote proves it. <shrug>
|
| ROTFL!

My sentiments exactly.

|
| >
| > > Here is the quote:
| > > "Sometimes people say quantum mechanics is all wrong. When the
particle
| > > arrived from the left, it's vertical momentum was zero**. And now
that
| > > it has gone through the slit, it's position is known. Both
position and
| > > momentum seem to be known with arbitrary accuracy.
| >
| > Feynman was writing with a clarity and precision that you lack. He
says
| > its vertical momentum _WAS_ zero when it arrived from the left, but
he
| > says nothing at all about its vertical momentum AFTER it goes
through
| > the slit. He says its position is known AFTER it has gone through
the
| > slit, but says nothing about its position BEFORE going through. And
he
| > says both position and momentum SEEM to be known with arbitrary
| > accuracy, but he never says that they ARE. In fact, his subsequent
|
| Let me refresh your faulty memory:
|
| I SAID:
| "Heiseinberg's uncertainty applies only to predictive measurements.
| There is nothing preventing you from knowing where a photon was and
how
| much momentum it had with arbitrary certainty. "
|
| YOU SAID:
| "It is not possible to know the values of conjugate variables
| precisely,
| for any system. Whether or not "future" and "past" (or your
| "prediction"
| and "initial state") apply to that depends on the variables and the
| system involved.... "
|
|
|
| > discussion explores that "SEEMS" and shows that indeed they never
are
| > (and never were!) known SIMULTANEOUSLY -- we knew its momentum
BEFORE it
| > went through the slit and we know its position immediately AFTER it
goes
| > through. <shrug>

He's fond of "<shrug>", isn't he? Perhaps he can't think.


| Hint: he ALWAYS knew the momentum WITHOUT MEASUREMENT and this was my
| point all along. This was the point you disagreed with all along
| (except now that you've changed your tune rather dramatically).
|
| I'll leave you with another of your blunders:
|
| ----
| > The uncertainty principle does not prohibit the arbitrarily precise
| > knowledge of a systems historical state.
|
| This is plain and simply not true.
| ----

<shrug>
Androcles
Bilge
2005-08-11 05:30:14 UTC
Permalink
Schoenfeld:
>Tom Roberts wrote:
>> ***@gmail.com wrote:
>> > Tom Roberts wrote:
>> >>You really should either look up this passage, or stop writing about
>> >>this. Your recollections are WRONG.
>> >
>> > My recollection is not wrong, [...]
>>
>> Yes it is, and your quote proves it. <shrug>
>
>ROTFL!

At least you are starting to laugh at your own mistakes.

>> > Here is the quote:
>> > "Sometimes people say quantum mechanics is all wrong. When the particle
>> > arrived from the left, it's vertical momentum was zero**. And now that
>> > it has gone through the slit, it's position is known. Both position and
>> > momentum seem to be known with arbitrary accuracy.
>>
>> Feynman was writing with a clarity and precision that you lack. He says
>> its vertical momentum _WAS_ zero when it arrived from the left, but he
>> says nothing at all about its vertical momentum AFTER it goes through
>> the slit. He says its position is known AFTER it has gone through the
>> slit, but says nothing about its position BEFORE going through. And he
>> says both position and momentum SEEM to be known with arbitrary
>> accuracy, but he never says that they ARE. In fact, his subsequent
>
>Let me refresh your faulty memory:
>
>I SAID:
>"Heiseinberg's uncertainty applies only to predictive measurements.
>There is nothing preventing you from knowing where a photon was and how
>much momentum it had with arbitrary certainty. "

That is wrong and the quote of feynman's that you supplied does nothing
to mitigate your error. At no time was there a state which had both a
well defined position and momentum. Such a state cannot be constructed.
px (as well as xp) is not hermitian.

>YOU SAID:
>"It is not possible to know the values of conjugate variables
>precisely, for any system. Whether or not "future" and "past" (or your
>"prediction" and "initial state") apply to that depends on the
>variables and the system involved.... "

Which is correct, as anyone could ascertain by simply looking at
the commutation relations (except perhaps you). The fact that
[p,q] = -i\hbar tells you immediately that p and q cannot both
be well defined simultaneously, since there exists _no_ state
vector for which p and q both have eigenvalues.

>> discussion explores that "SEEMS" and shows that indeed they never are
>> (and never were!) known SIMULTANEOUSLY -- we knew its momentum BEFORE it
>> went through the slit and we know its position immediately AFTER it goes
>> through. <shrug>
>
>Hint: he ALWAYS knew the momentum WITHOUT MEASUREMENT

Obviously that isn't possible. If you think so, then you can explain
precisely how anyone can know the momentum of a particle without measuring
it. Do you use a crystal ball?

>and this was my point all along. This was the point you disagreed with
>all along (except now that you've changed your tune rather dramatically).
>
>I'll leave you with another of your blunders:
>
>----
> > The uncertainty principle does not prohibit the arbitrarily precise
> > knowledge of a systems historical state.
>
>This is plain and simply not true.

Uhm,... that was your blunder that tom corrected, but it's nice of you
to correct your own blunder for once.
Bilge
2005-08-09 05:27:54 UTC
Permalink
***@gmail.com:
>Gregory L. Hansen wrote:
[...]
>> Oh, right, historical state. Slit with these dimensions, photon was
>> detected right there. And going from a wavefunction to a detection event
>> is something the philosophers are still arguing about.
>
>You can deduce the precise historical state of a quantum mechanical
>system without having measured it in the past.

No, you can't.

>Just look at the feynman
>integral. Going from a PRECISE state A to PRECISE state B has

An obvious counter example: Using your terminology, the
hydrogen ground state is a ``PRECISE state B.'' What was
``Precise state A?''

>probability of simply adding the amplitude of every possible path
>(varing the complex phase of that amplitude by the action of that path)
>and then simplying squaring the result.

Big deal. That means measuring a particle precisely at point
A and precisely at point B, leaves it's momentum completely
indeterminate (hence the need to use all possible paths). No
one said that you couldn't make two position measurements.
Position measuremets commute.

>This is why it's important to UNDERSTAND what it is QM is saying, as
>opposed to just rote learning the mathematical formulation and passing
>those abstract mathematical tools as physics.
>
Then take your advice and try to understand what quantum mechanics is
saying before talking about it. Canonically conjugate observables
cannot be simultaneously diaganolized and therefore cannot be
simultaneously observable. End of story.
Gregory L. Hansen
2005-08-09 14:34:13 UTC
Permalink
In article <***@o13g2000cwo.googlegroups.com>,
<***@gmail.com> wrote:
>
>Gregory L. Hansen wrote:
>> In article <***@z14g2000cwz.googlegroups.com>,
>> <***@gmail.com> wrote:
>> >
>> >Gregory L. Hansen wrote:
>> >> In article <***@g49g2000cwa.googlegroups.com>,
>> >> <***@gmail.com> wrote:
>> >> >
>> >> >kenseto wrote:
>> >> >> > > Doesn't that violate the Uncertainty Principle?
>> >> >> >
>> >> >> > No.
>> >> >>
>> >> >> Why not?...you know the path, the speed and the position of a
>single photon
>> >> >> from birth to detection. Why isn't that a violation of the UP?
>> >> >
>> >> >
>> >> >Heiseinberg's uncertainty applies only to predictive measurements.
>> >>
>> >> A diffracting grating with smaller spacing makes Bragg peaks that are
>> >> farther apart because reducing the spacings increases transverse momentum
>> >> of the interacting particles. An atom has size because the electron has
>> >> fallen as far into the nucleus as the uncertainty principle will let it
>> >> go, and it's a nucleus surrounded by an electron cloud rather than an
>> >> electron surrounded by a nuclear cloud because p=mv-- the larger particle
>> >> has a better defined position.
>> >>
>> >> The uncertainty principle doesn't turn off just because we're not looking.
>> >
>> >You didn't read what I said then proceeded to draw inferences all wrong
>> >and finished off with a sequence of irrelevant statements.
>> >
>> >The uncertainty principle does not prohibit the arbitrarily precise
>> >knowledge of a systems historical state. It only applies to predictions
>> >from an initial state. This is basic stuff.
>>
>> Oh, right, historical state. Slit with these dimensions, photon was
>> detected right there. And going from a wavefunction to a detection event
>> is something the philosophers are still arguing about.
>
>You can deduce the precise historical state of a quantum mechanical
>system without having measured it in the past. Just look at the feynman
>integral. Going from a PRECISE state A to PRECISE state B has
>probability of simply adding the amplitude of every possible path
>(varing the complex phase of that amplitude by the action of that path)
>and then simplying squaring the result.
>
>This is why it's important to UNDERSTAND what it is QM is saying, as
>opposed to just rote learning the mathematical formulation and passing
>those abstract mathematical tools as physics.

Well, the precise location of the scatterer and the detected probe
particle really isn't enough to determine the historical state. It won't
tell you, for instance, whether your peak is narrow or wide. It won't
tell you what an identically prepared system will do, or the geometry of
the crystal, or even whether you have a single scatterer or more.

You consider, say, a crystal with a cubic lattice versus a hexagonal
lattice to be parts of two different historical states, right?

--
"Suppose you were an idiot... And suppose you were a member of
Congress... But I repeat myself." - Mark Twain
Bilge
2005-08-06 22:26:44 UTC
Permalink
schoenfelch, bonehead from planet pinhead:
>
>kenseto wrote:
>> > > Doesn't that violate the Uncertainty Principle?
>> >
>> > No.
>>
>> Why not?...you know the path, the speed and the position of a single photon
>> from birth to detection. Why isn't that a violation of the UP?
>
>
>Heiseinberg's uncertainty applies only to predictive measurements.

Don't be an idiot. Too late. Never mind. The unceratinty principle
states that it is impossible to make simultaneous measurements of
non-commuting observables. As usual, you're wrong.

>There is nothing preventing you from knowing where a photon was and how
>much momentum it had with arbitrary certainty.

Except the uncertainty principle.
Gregory L. Hansen
2005-08-07 15:31:57 UTC
Permalink
In article <***@radioactivex.lebesque-al.net>,
Bilge <***@fghfgigtu.com> wrote:
>schoenfelch, bonehead from planet pinhead:
> >
> >kenseto wrote:
> >> > > Doesn't that violate the Uncertainty Principle?
> >> >
> >> > No.
> >>
> >> Why not?...you know the path, the speed and the position of a single photon
> >> from birth to detection. Why isn't that a violation of the UP?
> >
> >
> >Heiseinberg's uncertainty applies only to predictive measurements.
>
> Don't be an idiot. Too late. Never mind. The unceratinty principle
>states that it is impossible to make simultaneous measurements of
>non-commuting observables. As usual, you're wrong.
>
> >There is nothing preventing you from knowing where a photon was and how
> >much momentum it had with arbitrary certainty.
>
> Except the uncertainty principle.
>


Diffractive optics is a nice example of the uncertainty principle. In the
first place, for a diffraction pattern to appear at all it seems the probe
particles must sample extended regions of a crystal. Otherwise
information about the structure of the crystal wouldn't show up in the
scattering. And for a second, the smaller the lattice spacing is the
wider the probe particles will be scattered, conserving the product of the
transverse location with the tranverse momentum. And the limit would be
isotropic scattering for a point-like target-- as delta x goes to zero,
delta p gets really big.

But what do we say about a small sample in a highly collimated x-ray beam,
and a blip was detected at an angle of 23.357 degrees from the beam axis?

The angular resolution of the detectors isn't limited to the width of the
wavefunction at the sample. And it's a good thing, or else we wouldn't be
able to see diffraction patterns emerge over many scattering events.
Copenhaganists might say something about the collapse of the wavefunction.

--
"Don't try to teach a pig how to sing. You'll waste your time and annoy
the pig."
Tom Roberts
2005-08-07 16:55:19 UTC
Permalink
Gregory L. Hansen wrote:
> Diffractive optics is a nice example of the uncertainty principle. [...]

OK.


> But what do we say about a small sample in a highly collimated x-ray beam,
> and a blip was detected at an angle of 23.357 degrees from the beam axis?

We say that the uncertainty principle applies to CONJUGATE VARIABLES.
You seem to want to discuss position transverse to the beam and angle of
scattering -- those are not conjugate variables. <shrug>


> The angular resolution of the detectors isn't limited to the width of the
> wavefunction at the sample. And it's a good thing, or else we wouldn't be
> able to see diffraction patterns emerge over many scattering events.
> Copenhaganists might say something about the collapse of the wavefunction.

I have no idea what "Copenhagenists" would say, but anyone with
knowledge about QM would say: the uncertainty principle only applies to
conjugate variables.


Tom Roberts ***@lucent.com
the softrat
2005-08-08 02:29:46 UTC
Permalink
On Sun, 7 Aug 2005 15:31:57 +0000 (UTC),
***@steel.ucs.indiana.edu (Gregory L. Hansen) wrote:

>"Don't try to teach a pig how to sing. You'll waste your time and annoy
>the pig."

OK.

How do we drive all the pigs away from the "sci.physics" newsgroups?

I wouldn't TOUCH that bacon!


the softrat
Sometimes I get so tired of the taste of my own toes.
mailto:***@pobox.com
--
The early bird may get the worm, but the second mouse gets the
cheese. -- Steven Wright
Bilge
2005-08-03 08:07:49 UTC
Permalink
***@erinet.com:
>
>Roberts:
>Not true. Phototubes easily detect single UV photons, and NaI crystals
>easily convert single gamma ray photons into multiple UV/visible
>photons, which are easily detected by phototubes.
>
>Seto:
>So are you saying that you can generate and detect a single UV photon?

Of course. For example, the lyman series (E_n -> g.s.) in hydrogen
produces UV photons. Put some hydrogen at low pressure into a glass
tube and put the glass tube inside an rf coil. The most convincing
evidence that UV photons are produced is that you can look at the
discharge for a while and go blind.

>And you can generate a single gamma photon and convert it into multiple
>UV/visible photons?

Sure. It's done all the time. Compton shielded HPGe and Ge(Li)
detectors are made by surrounding the Ge crystal with additional
detectors, typically BGO. The gammas that are compton scattered
into the BGO produce photons in the visible range which are then
detected by photomultiplier tubes.

>Doesn't that violate the Uncertainty Principle?

No, why would it? For that matter, what does the uncertainty
principle have to do with it?
Gregory L. Hansen
2005-08-01 16:05:31 UTC
Permalink
In article <***@o13g2000cwo.googlegroups.com>,
Jerry T <***@soon.com> wrote:

>tom is confussed, the detected photons are
><averaged> not detected, photons cant be detected,

>light yes, but not photons

That might surprise some people I know that count visible light photons.

--
"The polhode rolls without slipping on the herpolhode lying in the
invariable plane." -- Goldstein, Classical Mechanics 2nd. ed., p207.
j***@aol.com
2005-08-02 08:03:20 UTC
Permalink
In article <dclh8b$boj$***@rainier.uits.indiana.edu>,
***@steel.ucs.indiana.edu (Gregory L. Hansen) wrote:
>In article <***@o13g2000cwo.googlegroups.com>,
>Jerry T <***@soon.com> wrote:
>
>>tom is confussed, the detected photons are
>><averaged> not detected, photons cant be detected,
>>š
>>light yes, but not photons
>
>That might surprise some people I know that count visible light photons.

I just got curious; is there a manufacturing process that needs
to count photons? This might not be a well-written question.
IOW, is there something that needs photons counted to be able
to make it?

/BAH


Subtract a hundred and four for e-mail.
Bilge
2005-08-03 07:57:08 UTC
Permalink
***@aol.com:
>In article <dclh8b$boj$***@rainier.uits.indiana.edu>,
> ***@steel.ucs.indiana.edu (Gregory L. Hansen) wrote:
>>In article <***@o13g2000cwo.googlegroups.com>,
>>Jerry T <***@soon.com> wrote:
>>
>>>tom is confussed, the detected photons are
>>><averaged> not detected, photons cant be detected,
>>>š
>>>light yes, but not photons
>>
>>That might surprise some people I know that count visible light photons.
>
>I just got curious; is there a manufacturing process that needs
>to count photons? This might not be a well-written question.
>IOW, is there something that needs photons counted to be able
>to make it?

Depends on what you mean. There are certainly a lot of applications
of photon counting in manufacturing. For example, any time you obtain
spectral lines, you are counting photons. The spectral line is just the
number of photons in a small number of adjacent bins of a histogram.
Any process that uses scintillators is a photon counting operation.
The energy of a charged particle is determined by integrating the
the current produced by the photons that land in a phototube or PIN diode.
If you look at the output of a phototube with enough resolution (a few
ns), for example, you will lots of spikes which form an evelope with
the characteristic response time of the scintillator. The integration over
that envelope is nominally proportional to the number of photons produced
by the charged particle.

Photon emission microspcopy is a photo counting process used
extensively in semiconductor manufacturing, but not for the
manufacturing, per se. It's used to find defects and figure out
how to improve the manufacturing process.

If you are asking for a manufacturing process in which counting only
a few photons is integral to the manufacture of a device, I would
doubt it. I doubt that sort of process would ever be useful, since
the only way to distinguish between a photon which is part of the
process and a random noise spike, is to have a statistically significant
number of photons that define a signal. In that case, you are back
to just integrating photon counts over some time interval. The fewer
photons you count per unit time, the longer you have to count to
be certain of your signal.
j***@aol.com
2005-08-03 07:48:15 UTC
Permalink
In article <***@radioactivex.lebesque-al.net>,
***@radioactivex.lebesque-al.net (Bilge) wrote:
> ***@aol.com:
> >In article <dclh8b$boj$***@rainier.uits.indiana.edu>,
> > ***@steel.ucs.indiana.edu (Gregory L. Hansen) wrote:
> >>In article <***@o13g2000cwo.googlegroups.com>,
> >>Jerry T <***@soon.com> wrote:
> >>
> >>>tom is confussed, the detected photons are
> >>><averaged> not detected, photons cant be detected,
> >>>š
> >>>light yes, but not photons
> >>
> >>That might surprise some people I know that count visible light
photons.
> >
> >I just got curious; is there a manufacturing process that needs
> >to count photons? This might not be a well-written question.
> >IOW, is there something that needs photons counted to be able
> >to make it?
>
> Depends on what you mean.

I wasn't sure what I meant. But you answered the question
to my satisfaction and gave a number of magic incantations
for me to remember. Thank you very much :-).

<reluctant snip>

/BAH

Subtract a hundred and four for e-mail.
Tom Roberts
2005-07-28 19:21:53 UTC
Permalink
sue jahn wrote:
> sue jahn wrote:: SR assumes there is an apparent conflict between Maxwell's
> equations and the principle of relativity. [...]
> I got the words from here:
> VII. The Apparent Incompatibility of the Law of Propagation of Light with the Principle of Relativity
> --Albert Einstein (1879-1955). Relativity: The Special and General Theory. 1920
> http://www.bartleby.com/173/7.html

You display the all too common problem around here: inability to read.
What you wrote it not at all contained in that reference. In particular,
SR does not "assume" this apparent incompatibility (as you claimed), it
_resolves_ it (as I pointed out, and as this article discusses).

Just "getting the words" is UTTERLY INADEQUATE. You must actually READ
them and UNDERSTAND them.


Tom Roberts ***@lucent.com
Jerry T
2005-07-28 19:31:04 UTC
Permalink
Tom Roberts wrote:
> sue jahn wrote:
> > sue jahn wrote:: SR assumes there is an apparent conflict between Maxwell's
> > equations and the principle of relativity. [...]
> > I got the words from here:
> > VII. The Apparent Incompatibility of the Law of Propagation of Light with the Principle of Relativity
> > --Albert Einstein (1879-1955). Relativity: The Special and General Theory. 1920
> > http://www.bartleby.com/173/7.html
>
> You display the all too common problem around here: inability to read.
> What you wrote it not at all contained in that reference. In particular,
> SR does not "assume" this apparent incompatibility (as you claimed), it
> _resolves_ it (as I pointed out, and as this article discusses).
>
> Just "getting the words" is UTTERLY INADEQUATE. You must actually READ
> them and UNDERSTAND them.
>
>
> Tom Roberts ***@lucent.com

you didnt contribute with any explanation here Tom
Sue...
2005-07-28 19:39:33 UTC
Permalink
Tom Roberts wrote:
> sue jahn wrote:
> > sue jahn wrote:: SR assumes there is an apparent conflict between Maxwell's
> > equations and the principle of relativity. [...]
> > I got the words from here:
> > VII. The Apparent Incompatibility of the Law of Propagation of Light with the Principle of Relativity
> > --Albert Einstein (1879-1955). Relativity: The Special and General Theory. 1920
> > http://www.bartleby.com/173/7.html
>
> You display the all too common problem around here: inability to read.
> What you wrote it not at all contained in that reference. In particular,
> SR does not "assume" this apparent incompatibility (as you claimed), it
> _resolves_ it (as I pointed out, and as this article discusses).
>
> Just "getting the words" is UTTERLY INADEQUATE. You must actually READ
> them and UNDERSTAND them.
>
>
> Tom Roberts ***@lucent.com

Well I surely don't read as carfully as you so I won't
even try to count the occurances of *Maxwell* in that chapter.

Had Einstein credited Weber, as Maxwell did, instead of
"every school child" he might have put his imaginary
axis in the near-field where it belongs and found no need for
funny clocks.

Sue...

http://farside.ph.utexas.edu/teaching/em1/lectures/node46.html
http://arxiv.org/abs/physics/0204034
http://www.ifi.unicamp.br/~assis/wpapers.htm


Sue...
Dirk Van de moortel
2005-07-27 19:35:13 UTC
Permalink
"Tom Roberts" <***@lucent.com> wrote in message news:dc8hb1$***@netnews.net.lucent.com...
> sue jahn wrote:
> > SR assumes there is an apparent conflict between Maxwell's
> > equations and the principle of relativity.
>
> Where do you get this stuff?? -- you must just make it up, as it is
> completely wrong.

Check Dennis McCarthy.

Dirk Vdm
Daryl McCullough
2005-07-28 15:29:36 UTC
Permalink
Dirk Van de moortel says...

>"Tom Roberts" <***@lucent.com> wrote in message
>news:dc8hb1$***@netnews.net.lucent.com...
>> sue jahn wrote:
>> > SR assumes there is an apparent conflict between Maxwell's
>> > equations and the principle of relativity.
>>
>> Where do you get this stuff?? -- you must just make it up, as it is
>> completely wrong.
>
>Check Dennis McCarthy.

Dirk,

Where did you get the idea that sue is Dennis McCarthy?

--
Daryl McCullough
Ithaca, NY
Dirk Van de moortel
2005-07-28 18:38:15 UTC
Permalink
"Daryl McCullough" <***@yahoo.com> wrote in message news:***@drn.newsguy.com...
> Dirk Van de moortel says...
>
> >"Tom Roberts" <***@lucent.com> wrote in message
> >news:dc8hb1$***@netnews.net.lucent.com...
> >> sue jahn wrote:
> >> > SR assumes there is an apparent conflict between Maxwell's
> >> > equations and the principle of relativity.
> >>
> >> Where do you get this stuff?? -- you must just make it up, as it is
> >> completely wrong.
> >
> >Check Dennis McCarthy.
>
> Dirk,
>
> Where did you get the idea that sue is Dennis McCarthy?

I'm not giving that away in public ;-)

Dirk Vdm
sue jahn
2005-07-28 19:06:21 UTC
Permalink
"Daryl McCullough" <***@yahoo.com> wrote in message news:***@drn.newsguy.com...
> Dirk Van de moortel says...
>
> >"Tom Roberts" <***@lucent.com> wrote in message
> >news:dc8hb1$***@netnews.net.lucent.com...
> >> sue jahn wrote:
> >> > SR assumes there is an apparent conflict between Maxwell's
> >> > equations and the principle of relativity.
> >>
> >> Where do you get this stuff?? -- you must just make it up, as it is
> >> completely wrong.
> >
> >Check Dennis McCarthy.
>
> Dirk,
>
> Where did you get the idea that sue is Dennis McCarthy?
>
> --
> Daryl McCullough
> Ithaca, NY
>

Don't you know?
Dirk is a master at probability and statistics.

http://groups-beta.google.com/group/sci.physics.relativity/search?hl=en&group=sci.physics.relativity&q=balance+wheel+&qt_g=1&searchn
ow=Search+this+group

http://groups-beta.google.com/group/sci.physics.relativity/search?hl=en&group=sci.physics.relativity&q=balance+wheel+dennis&qt_g=1&s
earchnow=Search+this+group

Well...
It shows more logic that some of his other notions. [eyes rolling]

Sue..
Orion
2005-08-06 20:03:15 UTC
Permalink
***@YAHOO.COM wrote:
> A contradictory assumption of current physics:
>
> SR assumes that the leading edge of a light ray from a source will hit
> the detector in the same frame of the source. This would mean that the
> position and velocity of the leading edge of the light ray(the first
> photon) is known exactly. This is a clear violation of the Uncertainty
> Principle.
>
> Ken Seto

The flaw in the UP is that is assumes that a particle occupies
position. Particles do not have direction or position.
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