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Re: Is photon a wave packet ?



In my opinion, M. Edmiston give us good question.
We can count photons to get an statistical picture,
but is this evidence of spatial distribution of them?

Barut et. al. look for an spatial description of the photon,
but I do not have basis to agree with that picture. Besides,
I must tell you that I do not have a clear idea. On the contrary,
looking at Kid, Ardini and Anton, Am J. Phys. 57, (1989), p. 27,
there are several ways to understand what the photon is.

Arnulfo Castellanos Moreno

----- Original Message -----
From: "Michael Edmiston" <edmiston@BLUFFTON.EDU>
To: <PHYS-L@lists.nau.edu>
Sent: Tuesday, May 14, 2002 9:10 AM
Subject: Re: Is photon a wave packet ?


John Denker is asking for a more clear question or reference to a specific
experiment. Perhaps the experiment and question below are the type of
thing
Arnulfo Castellanos Moreno was after.


Today we have the ability to do photon counting. That is, we believe we
can
detect a single photon. Several detection schemes are possible, but
common
detectors would be a photomultiplier tube for vis/UV or a solid state
detector for x-rays or gamma rays.

We can aim vis/UV photons at a diffraction grating, or we can aim
x-rays/gamma-rays at a crystal, and we can place the detector on a
goniometer arm and do single photon counting at a variety of angles.

We find that even at low incident flux the photons follow the diffraction
criteria normally associated with wave nature. The low flux implies a
single photon must be interacting alone with the grating, i.e. not with
other photons. The single photon detection at a specific time may imply a
localized entity. Hence, it would be reasonable to construe that single
photons are exhibiting wave-like properties.

(1) Is this a reasonable way to interpret the data?
(2) What, if any, spatial description of the photon can be inferred from
these data? For example, would it be reasonable to view the photon as a
wave packet?

Moreno will have to tell us if this is what he had in mind. It is what
came
to my mind as a result of reading his question.


Michael D. Edmiston, Ph.D. Phone/voice-mail:
419-358-3270
Professor of Chemistry & Physics FAX:
419-358-3323
Chairman, Science Department E-Mail
edmiston@bluffton.edu
Bluffton College
280 West College Avenue
Bluffton, OH 45817