Path: ...!news.mixmin.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Martin Brown <'''newspam'''@nonad.co.uk>
Newsgroups: sci.electronics.design
Subject: Re: Quantum mystics
Date: Mon, 10 Jun 2024 18:28:06 +0100
Organization: A noiseless patient Spider
Lines: 41
Message-ID: <v47d37$hnfj$2@dont-email.me>
References: <v44t6u$3n7fn$1@dont-email.me> <v4651b$1ejef$1@solani.org>
 <gm2e6jdple0j6iuskqjkig5vfcqruq7pj4@4ax.com> <v4799p$h5qj$2@dont-email.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Mon, 10 Jun 2024 19:28:07 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="151e811e6e95cd7b2ea8a77b54b302ce";
	logging-data="581107"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1/nO/tXELin4XIe2xxUDb0C4yjd6pEslpMTYOhboawGnQ=="
User-Agent: Mozilla Thunderbird
Cancel-Lock: sha1:f0+d/VH/B822EVmBZ3U9YF469RQ=
Content-Language: en-GB
In-Reply-To: <v4799p$h5qj$2@dont-email.me>
Bytes: 2908

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!

-- 
Martin Brown