MadSci Network: Physics
Query:

Subject: Just what is the size and shape of a photon?

Date: Fri Jan 17 10:07:55 2014
Posted by Matthew
Grade level: grad (science) School: Mad Scientist Moderator
City: Palo Alto State/Province: California Country: USA
Area of science: Physics
ID: 1389978475.Ph
Message:

Diffraction grating resolution is mN, (N = # of lines and m = order), but that is true if the photon 
interacts with ALL the lines, even if the grating is orders of magnitude larger than the photon's 
wavelength. The std. model of a photon should only be true if the photon is infinite in the time 
dimension (Fourier Xform of an infinite sine wave is a frequency delta function).  Both  imply that a 
photon is large spatially or temporally.  A double slit experiment increasing the distance between slits 
"ought to" show a decrease in interference, and the interaction "ought to" go to nil (lost in noise), and 
reveal the photon's "max. size".  Has this ever been done (not seen in my optics texts)?   As for time, the 
photon is maybe "long enough" (temporally)  that the spectrum of its "envelope" is nil, but I've never 
seen any experiments that say so.  I'd always assumed the photon was some sort of optical soliton wave 
(similar in concept to the matter soliton waves sometimes observed in canals), but now I'm having my 
doubts.  Anything to do with quantum phenomena is likely to be counterintuitive, so analogies may be 
way off the mark.  Lastly, has anyone ever published the actual equations for the spatial shape of the 
electric and magnetic waves of a photon for a given moment in time, or the full solution of the wave 
equation (spatial and temporal) for a photon.  I presume the equations to be solved are Maxwell's 
equations in absence of current or charge, i.e. (D represents the Del operator)  Del X E =  - dB/dt  ,  Del 
. E = 0  ,  Del . B = 0  ,  and Del X B = mu *epsilon* dE/dt   where E and B are both functions of x, y, z, 
and t.  The answer must of course be a traveling wave of some sort, but it need not be a simple single 
sine wave, and indeed could not be unless the photon was infinite in the time dimension.



Re: Just what is the size and shape of a photon?

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