Origin of 'Daemon' in Computing

Post by eru » Wed, Oct 23, 2024, 6:21 AM UTC

n4r9 wrote: post #110

eru wrote: post #109

Earlier quoted context omitted.

Air molecules are large and massive, so their de Broglie wavelength is actually much smaller than their physical size (and that's much smaller than the hole needs to be to let in one at a time at ambient pressure and temperature), and you don't need to know their speeds all that well, eg if you just want to 'pump' all the air from one chamber into another. So all in all, a classic description would work reasonably we…

I'm not sure I understand - why is the wavelength size relevant? In my understanding, the standard deviations of position and momentum are at least some constant multiple of Plank's constant.

Sorry, I meant to say that for particles (or collections of particles) with a short de Broglie wavelength classical effects dominate quantum effects.

The typical scale at which quantum effects dominate for a system is roughly equivalent to the de Broglie wavelength of the relevant parts.

Does that make sense?

Post by BlueTemplar » Mon, Nov 04, 2024, 10:45 AM UTC

Vecr wrote: post #105

BlueTemplar wrote: post #104

Earlier quoted context omitted.

No, got a link ? Searching for them did bring me to an interesting discussion : https://www.lesswrong.com/posts/YSFRazdoWXKHgNakz/link-the-b... (2015) and then to : https://bayes.wustl.edu/etj/articles/second.law.pdf (1998) Which confirms my suspicions, but also sheds lights on how old the confusion is ! There are a bunch of assumptions that are easy to make (because they almost always are true), but very hard to get…

https://arxiv.org/abs/1508.02421v1 https://arxiv.org/abs/1508.02421v3 (updated, 2017) They claim to fix the criticisms, see the section "The Bayesian arrow of time." Who knows how well they did though. As far as I can tell they're still making impossible assumptions, because certain Bayesian problems can't be calculated under a certain amount of energy, and some can't be calculated at all while embedded in spacetime…

Thanks, I need to look into those whenever I can find the time, however it also sounds like they are trying to fit General Relativity in there ?

I can't say for sure if this is doomed in the first place because GR infamously is not compatible with quantum mechanics (and trying to match them by force is only going to produce confusion and nonsense), or potentially revolutionary in actually managing to reconcile them...

Re: Origin of 'Daemon' in Computing

Re: Origin of 'Daemon' in Computing