Optical photon is an electromagnetic wave produced e.g. during deexcitation of an atom, carrying energy, momentum and angular momentum difference.
So how is this electromagnetic energy distributed in space (rho~|E|^2+|B|^2) - what is the shape and size of a single photon? What is the position distortion of such wavepacket?
Looking for literature, I have found started by Geoffrey Hunter, here is one of the articles: "Einstein’s Photon Concept Quantified by the Bohr Model of the Photon" https://arxiv.org/abs/quant-ph/0506231
Most importantly, he claims that such single optical photon has a shape similar to an elongated ellipsoid of length being wavelength λ, and diameter λ/π (?), providing reasonably looking arguments:
- Its length of λ is confirmed by:
– the generation of laser pulses that are just a few periods long;
– for the radiation from an atom to be monochromatic (as observed), the emission must take place within one period ;
– the sub-picosecond response time of the photoelectric effect ;
- The diameter of λ/π is confirmed by:
– he attenuation of direct (undiffracted) transmission of circularly polarized light through slits narrower than λ/π: our own measurements of the effective diameter of microwaves [8,p.166] confirmed this within the experimental error of 0.5%;
– the resolving power of a microscope (with monochromatic light) being “a little less than a third of the wavelength”; λ/π is 5% less than λ/3, ;
Is it the proper answer?
Are there other reasonable answers, preferably experimental arguments?
Update: similar conclusions from the different author: https://arxiv.org/pdf/1604.03869
the length of a photon is half of the wavelength, and the radius is proportional to the square root of the wavelength
Update: 2021 "The size and shape of single-photon" http://dx.doi.org/10.4236/oalib.1107179
Attosecond chronoscopy brings hope to verify e.g. photon models experimentally - gathered: https://scholar.google.pl/scholar?cites=15193546925951882986&as_sdt=2005&sciodt=0,5&hl=en E.g. 2020 "Probing molecular environment through photoemission delays" https://www.nature.com/articles/s41567-020-0887-8
Attosecond chronoscopy has revealed small but measurable delays in photoionization, characterized by the ejection of an electron on absorption of a single photon. Ionization-delay measurements in atomic targets provide a wealth of information about the timing of the photoelectric effect, resonances, electron correlations and transport.