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Quantum Double-Slit Experiment Offers Hope for Earth-Size Telescope

quantamagazine.org

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Re: Quantum Double-Slit Experiment Offers Hope for Earth-Size Telescope

#41

Post by jfengel »

ars wrote: post #28
jfengel wrote: post #17

Earlier quoted context omitted.

"Configuration space" means that the state of the world is described by some list of numbers that don't actually correspond directly to locations in space or time. Or even mass or energy. It means that those things aren't really fundamental. What's fundamental is some other set of things that aren't too difficult to work with mathematically, but which don't correspond exactly to anything you're familiar with. The bes…

> means that the state of the world is described by some list of numbers How is that different from hidden variables?

The difference is that they're not localized. It's only local hidden variables that are forbidden by theory.

One way to look at it is that every one of those pieces of configuration space apply to all of space and all of time. That's not forbidden. But it also means that these values aren't directly accessible. They can only be partially inferred.

Re: Quantum Double-Slit Experiment Offers Hope for Earth-Size Telescope

#42

Post by NZGumboot »

iaw wrote: post #38

I couldn't find via Ctrl+F, it sounds like this exceeds the Rayleigh Criterion, is that correct?

No, the Rayleigh Criterion is still correct, you just have to consider the "aperture size" to be the size of the combined multi-telescope device (which would be the size of the Earth if the telescopes are on the opposite sides of the Earth). In practice to get the best quality image you need a telescope every X meters (I'm not sure the exact distance required) but even a 2x2 telescope array over a large distance would still give you significantly more resolving power than just a single telescope on it's own.

Re: Quantum Double-Slit Experiment Offers Hope for Earth-Size Telescope

#43

Post by magicalhippo »

Moodles wrote: post #4

That animation at the top of the article of the possible locations of the photon is very cool. Quantum behavior seems so counterintuitive to us because we're just apes who evolved minds to survive in the macroscopic world of the African savanna. But I wonder if we perhaps taught quantum behavior to kids from an early age, whether they could get an intuitive understanding for it, in the the same way that I can, like,…

> Quantum behavior seems so counterintuitive

While I still feel just that, this post[1] and its reference to Scott Aaronson's lecture[2] on how QM can be seen as a "inevitable" generalization of probability theory did make quantum mechanics more... comforting? acceptable? Something like that.

[1]: https://www.physicsforums.com/threads/probability-theory-and...

[2]: https://www.scottaaronson.com/democritus/lec9.html

Re: Quantum Double-Slit Experiment Offers Hope for Earth-Size Telescope

#44

Post by Smithalicious »

jfengel wrote: post #41
ars wrote: post #28

Earlier quoted context omitted.

> means that the state of the world is described by some list of numbers How is that different from hidden variables?

The difference is that they're not localized. It's only local hidden variables that are forbidden by theory. One way to look at it is that every one of those pieces of configuration space apply to all of space and all of time. That's not forbidden. But it also means that these values aren't directly accessible. They can only be partially inferred.

So the universe is governed by inaccessible magic numbers, like a kind of divine DRM?

Re: Quantum Double-Slit Experiment Offers Hope for Earth-Size Telescope

#45

Post by andi999 »

infogulch wrote: post #20
andi999 wrote: post #8

Earlier quoted context omitted.

You can't. This is just covered by classical electrodynamics. Of course in a sense you can say anything is quantum, but then the stability of a table is quantum (which it is). If you were to have a single photon source and avalanche detector, ok now you are talking quantum.

The first 2 minutes of that video make it clear that they think it is "real" quantum effects (e.g. at 1:34 entanglement > EPR paradox > Bell's Theorem > local realism). Those are pretty quantum-y imo.

If you have entanglement then it is quantum. Yes. But the comment was you 'just' need polarized glasses. So if 'just' polarized glasses for a few $ means: "and of course a biphoton source for a couple of thousand $ and some coincidence counters for another couple of thousand $", then you only 'just' need polarizers.

Re: Quantum Double-Slit Experiment Offers Hope for Earth-Size Telescope

#46

Post by Smithalicious »

Smithalicious wrote: post #44
jfengel wrote: post #41

Earlier quoted context omitted.

The difference is that they're not localized. It's only local hidden variables that are forbidden by theory. One way to look at it is that every one of those pieces of configuration space apply to all of space and all of time. That's not forbidden. But it also means that these values aren't directly accessible. They can only be partially inferred.

So the universe is governed by inaccessible magic numbers, like a kind of divine DRM?

This is being downvoted, perhaps because I put a humorous analogy in there, but I really am curious, isn't this what is claimed? The "real" ground truth of the universe is "configuration space", which is some kind of mathematical construct, and which can't be perceived directly but only partially inferred?

I'd like to know more about this since I have never heard of this concept before and I feel like it has far-reaching implications

Re: Quantum Double-Slit Experiment Offers Hope for Earth-Size Telescope

#47

Post by boublepop »

baldeagle wrote: post #15
lisper wrote: post #10

Earlier quoted context omitted.

It's actually not that hard to get an intuitive understanding of QM even as an adult. The key is having the right pedagogy, which is very rare. IMHO the key to the right pedagogy is just one crucial insight: the wave function lives in configuration space , not in physical space. How physical space emerges from configuration space is a deep mystery. No one knows. But it is CRUCIAL not to conflate these two things. Mos…

I’m not sure I’m following… are you saying that the wave functions are just a yaml for the behavior in physical space?

The wave function is “the sum of faces on two rolled d6” reality is “it they landed with a sum of 8”.

Re: Quantum Double-Slit Experiment Offers Hope for Earth-Size Telescope

#48

Post by iaw »

NZGumboot wrote: post #42
iaw wrote: post #38

I couldn't find via Ctrl+F, it sounds like this exceeds the Rayleigh Criterion, is that correct?

No, the Rayleigh Criterion is still correct, you just have to consider the "aperture size" to be the size of the combined multi-telescope device (which would be the size of the Earth if the telescopes are on the opposite sides of the Earth). In practice to get the best quality image you need a telescope every X meters (I'm not sure the exact distance required) but even a 2x2 telescope array over a large distance woul…

Thank you!

Re: Quantum Double-Slit Experiment Offers Hope for Earth-Size Telescope

#49

Post by jfengel »

Smithalicious wrote: post #46
Smithalicious wrote: post #44

Earlier quoted context omitted.

So the universe is governed by inaccessible magic numbers, like a kind of divine DRM?

This is being downvoted, perhaps because I put a humorous analogy in there, but I really am curious, isn't this what is claimed? The "real" ground truth of the universe is "configuration space", which is some kind of mathematical construct, and which can't be perceived directly but only partially inferred? I'd like to know more about this since I have never heard of this concept before and I feel like it has far-reac…

It's not quite as dramatic as it sounds. It's a somewhat more mathematically sound way of saying all of the usual stuff about quantum mechanics. It just takes the QM side more seriously, rather than trying to describe it as a bag on the side of classical physics.

The unobservable parts are not really any different from indirectly inferred concepts like potential energy. It's just that even seemingly concrete notions like location turn out to be macro scale approximations of this phase space. They're not accessible only because you are a macro scale object. You can very much demonstrate that it's real by simple experiments. You just need to be able to take them seriously, which is unexpectedly difficult because classical physics seems so intuitively obvious.

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