Path: ...!weretis.net!feeder8.news.weretis.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Phil Hobbs Newsgroups: sci.electronics.design Subject: Re: Quantum mystics Date: Mon, 10 Jun 2024 18:40:51 -0000 (UTC) Organization: A noiseless patient Spider Lines: 71 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Injection-Date: Mon, 10 Jun 2024 20:40:51 +0200 (CEST) Injection-Info: dont-email.me; posting-host="3f07d48eb33b83eb162af14468bab0e3"; logging-data="624275"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+vWAiHXjwQrnu7ZBRjef1s" User-Agent: NewsTap/5.5 (iPhone/iPod Touch) Cancel-Lock: sha1:0ScbUe4RMUy0r0+TjM9KPbNSZ3w= sha1:Sr/vE3sl6yLq1dr5rvhfdl5zQgc= Bytes: 4361 Phil Hobbs wrote: > Martin Brown <'''newspam'''@nonad.co.uk> wrote: >> On 10/06/2024 17:25, Jeroen Belleman wrote: >>> On 6/10/24 16:20, john larkin wrote: >> >>>> But photon entanglement can't be explained, or even thought about, in >>>> classic-physics terms. >>>> >>>> Nor can single-photon interferance. >>>> >>>> Just accept and enjoy it. >>> >>> That's false! Entanglement and interference can easily be understood >>> in terms of waves and quantized detectors. It's the QM view, with its >>> imagined photon particle flying everywhere at once that is confusing. >> >> But that world view is backed up by experiments. >> >> Particles can behave as waves and waves can behave as particles >> depending on the experiment. The particle isn't "everywhere at once" >> either it is trapped in a spherical shell radius vt expanding around its >> point of origin with the amplitude of the wavefunction representing the >> chances of finding it at any particular position. >> >>> What size do you imagine a photon to be? >> >> Depends on the wavelength of the photon but to have a well defined >> frequency the amplitude envelope has to be a good few wavelengths long >> and to agree with causality the leading edge must be zero until >> sufficient time has passed from its emission to reaching its target. I >> expect that there is a canonical shape for a photon amplitude envelope >> for given df/f but I don't know what it is or if it has ever been computed. >> >> This aspect of size of a photon always seemed very awkward to me when >> working at 21cm neutral hydrogen and measuring what are essentially tiny >> correlations in narrowband random noise from extremely remote mostly >> point sources over a large number of different antenna pairs. What is >> pretty clear is that the correlations of such signals are good enough >> even on planetary dimensions for VLBI to work! > (Edited for clarity—posting from my phone) > Sticking with the semiclassical picture of photodetection is good, because > it avoids almost all of the blunders made by the photons-as-billiard-balls > folk, but it doesn’t get you out of the mystery. > > The really mysterious thing about photodetection is that a given photon (*) > > incident on a large lossless detector gives rise to exactly one detection > event, with probability spatialy and temporally weighted by E**2. > > Doesn’t seem so bad yet, but consider this: > If the detector is large compared with the pulse width/c, distant points on > the detector are separated by a spacelike interval. > > That means that when point A detects it, there is no way for that > information to reach point B before the end of the pulse, when E drops to > zero, and yet experimentally point B doesn’t detect it. > > (*) a quantized excitation of a harmonic oscillator mode of the EM field in > a given set of boundary conditions) > > Cheers > > Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics