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Physicists Create World’s First Time Crystal

technologyreview.com

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Re: Physicists Create World’s First Time Crystal

#31

Post by dysfunctor »

timelincoln wrote: post #18
dysfunctor wrote: post #16

I don't know anything about anything, but I want to enumerate some things I learned reading this article, and if someone actually knows what they're talking about and sees fit to take pity on me, please correct me so that I can understand what this actually means. So a time crystal appears to be made up of real matter. The article mentions ions that are arranged in a certain particular way, cooled in order to reduce…

I definitely don't think the conclusion is that the universe is non-deterministic, the idea is that when energy is lost symmetry is broken, and motion through time seems to be analogous to shape in space, in terms of this symmetry breaking effect.

Can you explain what you mean when you say motion through time, and shape in space?

I was under the impression that the whole idea of time symmetry revolved around being able to "zip/fold/traverse/map" both forwards and backwards in time. It's my understanding that such a concept would imply determinism, because time is really just a set of states, in the smallest possible interval of time.

I also don't understand why the time crystal loses energy over time if it is trapped in a temporal loop. I mean obviously there's not such a thing as perpetual energy, but I would think that the energy of a certain object at a particular frame in the set of states that is time, then when it returns to that state from either direction, it should be the same.

Edit: This is meant to be inquisitive, not necessarily interrogative. Thanks!

Re: Physicists Create World’s First Time Crystal

#33

Post by contravariant »

dysfunctor wrote: post #16

I don't know anything about anything, but I want to enumerate some things I learned reading this article, and if someone actually knows what they're talking about and sees fit to take pity on me, please correct me so that I can understand what this actually means. So a time crystal appears to be made up of real matter. The article mentions ions that are arranged in a certain particular way, cooled in order to reduce…

>They did this, and observed the ions changing in such a way where there was no driving influence and it's implied that the reason that this behavior was observed is because time symmetry was broken, which is just a fancy way of alleging that the universe is non-deterministic, I think.

Time translational symmetry and determinism have nothing to do with one another. Even a classical pendulum breaks time translational symmetry yet it's fully deterministic. In this cases they do break the symmetry in a more fundamental way, but it still doesn't say anything about determinism.

Re: Physicists Create World’s First Time Crystal

#35

Post by jacquesm »

rbanffy wrote: post #20
krapp wrote: post #17

Earlier quoted context omitted.

apparently yes, but because it's in a low energy state, it's impossible to extract any energy from it and do work (otherwise it would be a perpetual motion machine.)

It's interesting it is a perpetual motion machine, but it works only as long as you don't use it.

Any atomic nucleus with orbiting electrons fulfills that requirement, you could loosely call those time crystals too.

Their half life for most stable atoms is so long that perpetual applies for most practical uses of the word.

Which makes me wonder if these time crystals have a half-life too.

Re: Physicists Create World’s First Time Crystal

#36

Post by _puk »

brathouz wrote: post #22
panglott wrote: post #4

What are time crystals? Try this: Physicists Predict The Existence of Time Crystals https://www.technologyreview.com/s/426917/physicists-predict...

This is also helpful: How to Build A Space-Time Crystal https://www.technologyreview.com/s/428334/how-to-build-a-spa...

Thanks for both those links.

That article is from 2012 and quotes:

"If that’s the case, we ought to be reading the details about the first space-time crystal sometime in the days and weeks to come. "

Was there something non obvious they had to overcome that took the extra few years to produce these space-time crystals?

(I use the term non obvious as if this was not all way beyond my ken!)

Re: Physicists Create World’s First Time Crystal

#38

Post by davesque »

I figured this article would fly over my head (which it mostly did), but it was actually a very fun read. My main takeaway was the paradox that the interesting arrangement of matter could be in its lowest energy state, yet still moving. And that no energy could be extracted from this movement. I'm probably butchering the concept with my misuse of terminology but whatevs.

Re: Physicists Create World’s First Time Crystal

#39

Post by ww520 »

radarsat1 wrote: post #24
krapp wrote: post #17

Earlier quoted context omitted.

apparently yes, but because it's in a low energy state, it's impossible to extract any energy from it and do work (otherwise it would be a perpetual motion machine.)

right, now i'll have to read the article to understand why there is no energy loss :) it does seem to be breaking some rules.. but I guess that's the achievement here. Intuitively there should be some concept of friction/heat loss but maybe on this scale things are different. Maybe it could be exploited as a battery? A way of capturing energy into a stable kinetic "state". (Like a flywheel..)

Moving doesn't implement energy loss automatically. When things are set in motion, they will continue to move infinitely unless interfered by outside forces.
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