Timeline for Does a single white photon exist?
Current License: CC BY-SA 4.0
8 events
| when toggle format | what | by | license | comment | |
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| Nov 20, 2018 at 0:24 | comment | added | S. McGrew | If measurement of the polarization of a photon yields a specific value, it does not prove that the photon has a definite polarization before the measurement. Similarly, if the frequency (energy) of a single photon is measured to have a specific value, it does not show that the photon before measurement had a definite frequency. | |
| Nov 20, 2018 at 0:17 | comment | added | S. McGrew | I am asserting that it's possible to set up an experiment whose results are most reasonably explained by saying that a laser having a finite line width produces mixed-state photons having the same frequency mix as the laser. I think the experiment I proposed would fit the bill. | |
| Nov 20, 2018 at 0:07 | comment | added | S. McGrew | That argument could be used to say that no photon exists in a mixed state of any sort at all. In practice, we produce a lot of photons under identical conditions and measure the state of each photon individually, as in the single-photon double slit experiment. Even though the individual measurements yield definite results, the measurements all together are taken as proof that the photons are all in the same mixed state. | |
| Nov 19, 2018 at 23:56 | comment | added | Philip Oakley | For a laser we are producing a very large number of photons. There are various ensemble statistics therein. However in this case we are looking at just a single photon, so the 'statistic' aspect wouldn't be valid here. At the moment we are in a catch 22 scenario where it is [normally] claimed that we cannot in anyway measure or infer the measurement of these two apparently distinct characteristics because the theory suggests that they are bound to the same fundamental constant (which may have a systematic error, but no experimental error...) | |
| Nov 18, 2018 at 1:24 | comment | added | S. McGrew | Per the Heisenberg uncertainty principle, the product of energy uncertainty and time of emission (which translates to phase) is always finite. Every laser has a finite linewidth, and that line width is a characteristic of the photons comprising the laser's emission. That is, the frequency of each photon is indeterminate within the line width of the laser. | |
| Nov 17, 2018 at 22:10 | comment | added | Philip Oakley | However, I'm still of the opinion that each photon has a single precise frequency defined by its energy. And that it can only have one of two polarisations, left and right circular (otherwise that aspect would not be quantum). It's likely that the rotational frequency is the constant, while the direction of travel shape is more wavelet, and it is ultimately quaternionic (as per Maxwell, Art 618/9 IIRC). | |
| Nov 17, 2018 at 21:43 | comment | added | Philip Oakley | Interesting, especially as an experiment is proposed. the question is whether it effectively measures the single photon twice, or different photons on each measurement (similar to the use of two photon emission for twin slit checking). I believe there is already a similar experiment for producing super intense pulses by the reverse process with a chirped laser (FROG - en.wikipedia.org/wiki/Frequency-resolved_optical_gating) | |
| Sep 11, 2018 at 6:22 | history | answered | S. McGrew | CC BY-SA 4.0 |