10 ms·

Physicists link two time crystals in seemingly impossible experiment

171 points by galaxyLogic 4y ago

bee_rider 4y ago
> It wouldn't mean free energy — the motion associated with a time crystal doesn't have kinetic energy in the usual sense, but it could be used for quantum computing. I'm not smart enough to have anything really insightful to say about the article. But I don't know if it is more amusing or vaguely annoying that a technobabble phrase like "we'll have to pick up more time crystals for the ship's navigation computer to keep functioning" could be realistic in the future. Or, if it isn't realistic, the real show-stopper could just be the lack practical long distance space travel.
- colpabar 4y ago
  Ha - I came here to post pretty much the same thing. It always makes me wonder which came first. Did sci-fi/literature-at-large start using crystals this way after we started using them for time purposes, or did humans just always think crystals were cool and somehow supernatural and it just turns out we can use crystals to keep time? Probably the latter, given that humans do love shiny rocks, and they've existed much longer than we have.
  - ghostly_s 4y ago
    We've been using crystals to keep time for over 100 years.
    - ncmncm 4y ago
      And the better watches had them for more centuries.
  - bee_rider 4y ago
    Apparently (based on the article) these time crystals were thought up in 2012. I'm sure you could find the phrase "time crystal" in sci-fi previously. In fact I bet the person who thought the idea up was extremely pleased that they could get such a cool sci-fi sounding name for their thought experiment. On the other hand, crystal oscillators (riffing off your "using crystals [...] for time purposes") go way back, and pre-date Star Trek style technobabble I guess. But the idea of "magical crystals" goes back even further, and the thing that makes them interestingly shiny is tied to their structure. So I guess we knew there was something kind of funky going on there but didn't have the science to describe it really well. And what's sci-fi anyway? If someone in like 1800 wrote a story about teaching rocks to think, we'd probably call it fantasy. It just so happens that we managed to pull that idea from magic to reality. (reference to): https://twitter.com/daisyowl/status/841802094361235456 https://twitter.com/daisyowl/status/841802094361235456 Actually, the more I think about it, the more I think your "or" should just be treated as an inclusive or, and answered with "yes."
    - SoftTalker 4y ago
      Yeah "time crystal" will always make me think of Doctor Who. Not sure if they were ever actually mentioned in any story lines, but it sounds like something their writers would come up with.
- colordrops 4y ago
  One thing I've learned over time is that absurd and even naive-seeming sci-fi premises can and do become reality. I remember watching The Net with Sandra Bullock and laughing at the stupid representation of a website with sound and animation. How naive! And I also remember reading about "online" money that could be stolen like gold and held on a drive. How silly these sci-fi writers were back in the day.
  - thinkingemote 4y ago
    Maybe the classic early net crack pot website The Time Cube will prove to be true after all!
theteapot 4y ago
As is usually the case with any advanced physics / astrophysics article I read, I can't get into the article because I'm stuck mulling over a premise. Article states: > The laws of physics are symmetric through space ... But in a crystal, this gorgeous symmetry gets broken. The molecules of a crystal arrange themselves in a preferred direction, creating a repeating spatial structure. In the jargon of physicists, a crystal is a perfect example of "spontaneous symmetry breaking" — the fundamental laws of physics remain symmetric, but the arrangement of the molecules is not. I don't understand how crystals break spatial symmetry. Are we talking about some absolute spatial directional bias? If it's just relative the crystal lattice itself I can't see how that breaks symmetry.
- dannyz 4y ago
  If you imagine every molecule in the crystal can be oriented randomly, then there is a very large number of possible global configurations that are equally likely and we say the crystal is "symmetric" with respect to these outcomes. If the orientations become ordered in some fashion as the article is saying we say the symmetry is broken.
- sigmoid10 4y ago
  Symmetry becomes much more easy to grasp if you think of it only in terms of transformations - in this case coordinate transformations. If you for example rotate your system by a few degrees, does it look the same if you were to overlay it with the initial state (imagine the crystal as an infinite lattice). If yes, you have found a symmetry. For a crystal structure, you usually only have some discrete symmetries, i.e. you can maybe rotate by multiples of 90 degrees or shift axes by multiples of a certain length, but apart from these things the "inherent" rotational and translational symmetry of empty space is gone. What they're calling "spontaneous symmetry breaking" here is technically correct, but in this context it's a pretty trivial observation (I mean, yeah, it is a lattice after all) without any deep insight, as opposed to the Higgs mechanism for example.
  - zarzavat 4y ago
    It’s counterintuitive because most people are more familiar with the mathematical concept of symmetry whereby a lattice has more symmetry than a random set of points (which almost certainly has no symmetry at all). However from the physics point of view, the random set of points is more symmetrical than the lattice because there’s no way of telling which way a random set of points is oriented.
hangonhn 4y ago
In case anyone else is as confused about time crystals as I was, Physics Girl recently released a video on YouTube that does a decent job of explaining it: https://www.youtube.com/watch?v=ieDIpgso4no https://www.youtube.com/watch?v=ieDIpgso4no
moffkalast 4y ago
> time crystals, which are strange quantum systems that are stuck in an endless loop to which the normal laws of thermodynamics do not apply And here I was thinking they were talking about crystal oscillators.
- mensetmanusman 4y ago
  Replace ‘time crystals’ with MS Windows
  - deleted 4y ago
    [deleted]
- cpncrunch 4y ago
  It sounds like it's not really a "crystal" as such. I wonder if the person who came up with this term was a scifi fan. It sounds like the kind of thing that would be in Dr Who or Star Trek.
  - userbinator 4y ago
    It reminded me of https://en.wikipedia.org/wiki/Time_Cube https://en.wikipedia.org/wiki/Time_Cube
  - euroderf 4y ago
    Dilithium is just a quark-boson metacrystal, don'cha know.
drc500free 4y ago
This article perfectly bookends my abandoned physics degree. 1. This reminds me a bit of the delayed-choice quantum eraser, which is one of the weirdest scientific outcomes and is the sort of thing that inspired me to pursue a physics degree. It implies a certain kind of time travel is possible, in the sense that in the present moment we can cause some past moments to collapse. 2. As my TA, Frank Wilczek successfully scared me off that physics degree by simply being so smart and having complicated things come so easily to him. Being confronted with the kind of horsepower needed to be successful in academic physics was eye-opening.
- quickthrower2 4y ago
  2. Seems sad to me, his job was to make sure you are inspired, or at least informed to make a wise choice, but not scared off. But maybe he didn't know.
  - taneq 4y ago
    Sounds like “informed to make a wise choice” still applies? I had a similar experience with mathematics, having been “good at maths” in high school and then making friends in university with people who are ACTUALLY good at maths.
  - drc500free 4y ago
    He definitely didn't know (he was just excited about showing us Einstein summation notation), and he definitely informed me to make a wise choice. Not every degree program is about ensuring the best median performance, some are only concerned with picking out the world-changers. And that's okay.
    - bognition 4y ago
      As a disillusioned phd I appreciate your response here. For years I’ve beaten myself up for not doing noteworthy science. For some reason your words have washed away a lot of guilt.
      - 4y ago
V__ 4y ago
Coincidentally, I came across a video today which describe in laymen terms what time crystals are: https://www.youtube.com/watch?v=ieDIpgso4no https://www.youtube.com/watch?v=ieDIpgso4no tl;dw: Crystals are materials which atoms or molecules are aranged in a repeating manner. Time crystals are a material which isn't just repeating in the three dimensions of space but also in the "time dimension". Basically, the quantum spin of the material switches regularly, even though no energy is being applied.
- jthrowsitaway 4y ago
  Thanks, but I couldn't watch more than 30 seconds of that video. The cuts every 3 seconds or when the speaker took a slight pause is maddening.
paraiuspau 4y ago
Uncle Rico can finally go back and take State.
zackees 4y ago
Time crystals should be called Perpetual resonance waves in a bose-einstein condensate.
jagged-chisel 4y ago
This is why browsers have reader mode.
deleted 4y ago
[deleted]
Technetium 4y ago
Physics Girl did a fantastic video explaining this in layman's terms: https://www.youtube.com/watch?v=ieDIpgso4no https://www.youtube.com/watch?v=ieDIpgso4no (4:55-6:49 is a sponsor)

171 points by galaxyLogic 4y ago

> It wouldn't mean free energy — the motion associated with a time crystal doesn't have kinetic energy in the usual sense, but it could be used for quantum computing. I'm not smart enough to have anything really insightful to say about the article. But I don't know if it is more amusing or vaguely annoying that a technobabble phrase like "we'll have to pick up more time crystals for the ship's navigation computer to keep functioning" could be realistic in the future. Or, if it isn't realistic, the real show-stopper could just be the lack practical long distance space travel.

colpabar 4y ago
Ha - I came here to post pretty much the same thing. It always makes me wonder which came first. Did sci-fi/literature-at-large start using crystals this way after we started using them for time purposes, or did humans just always think crystals were cool and somehow supernatural and it just turns out we can use crystals to keep time? Probably the latter, given that humans do love shiny rocks, and they've existed much longer than we have.
- ghostly_s 4y ago
  We've been using crystals to keep time for over 100 years.
  - ncmncm 4y ago
    And the better watches had them for more centuries.
- bee_rider 4y ago
  Apparently (based on the article) these time crystals were thought up in 2012. I'm sure you could find the phrase "time crystal" in sci-fi previously. In fact I bet the person who thought the idea up was extremely pleased that they could get such a cool sci-fi sounding name for their thought experiment. On the other hand, crystal oscillators (riffing off your "using crystals [...] for time purposes") go way back, and pre-date Star Trek style technobabble I guess. But the idea of "magical crystals" goes back even further, and the thing that makes them interestingly shiny is tied to their structure. So I guess we knew there was something kind of funky going on there but didn't have the science to describe it really well. And what's sci-fi anyway? If someone in like 1800 wrote a story about teaching rocks to think, we'd probably call it fantasy. It just so happens that we managed to pull that idea from magic to reality. (reference to): https://twitter.com/daisyowl/status/841802094361235456 https://twitter.com/daisyowl/status/841802094361235456 Actually, the more I think about it, the more I think your "or" should just be treated as an inclusive or, and answered with "yes."
  - SoftTalker 4y ago
    Yeah "time crystal" will always make me think of Doctor Who. Not sure if they were ever actually mentioned in any story lines, but it sounds like something their writers would come up with.
colordrops 4y ago
One thing I've learned over time is that absurd and even naive-seeming sci-fi premises can and do become reality. I remember watching The Net with Sandra Bullock and laughing at the stupid representation of a website with sound and animation. How naive! And I also remember reading about "online" money that could be stolen like gold and held on a drive. How silly these sci-fi writers were back in the day.
- thinkingemote 4y ago
  Maybe the classic early net crack pot website The Time Cube will prove to be true after all!

theteapot 4y ago

As is usually the case with any advanced physics / astrophysics article I read, I can't get into the article because I'm stuck mulling over a premise. Article states: > The laws of physics are symmetric through space ... But in a crystal, this gorgeous symmetry gets broken. The molecules of a crystal arrange themselves in a preferred direction, creating a repeating spatial structure. In the jargon of physicists, a crystal is a perfect example of "spontaneous symmetry breaking" — the fundamental laws of physics remain symmetric, but the arrangement of the molecules is not. I don't understand how crystals break spatial symmetry. Are we talking about some absolute spatial directional bias? If it's just relative the crystal lattice itself I can't see how that breaks symmetry.

dannyz 4y ago
If you imagine every molecule in the crystal can be oriented randomly, then there is a very large number of possible global configurations that are equally likely and we say the crystal is "symmetric" with respect to these outcomes. If the orientations become ordered in some fashion as the article is saying we say the symmetry is broken.
sigmoid10 4y ago
Symmetry becomes much more easy to grasp if you think of it only in terms of transformations - in this case coordinate transformations. If you for example rotate your system by a few degrees, does it look the same if you were to overlay it with the initial state (imagine the crystal as an infinite lattice). If yes, you have found a symmetry. For a crystal structure, you usually only have some discrete symmetries, i.e. you can maybe rotate by multiples of 90 degrees or shift axes by multiples of a certain length, but apart from these things the "inherent" rotational and translational symmetry of empty space is gone. What they're calling "spontaneous symmetry breaking" here is technically correct, but in this context it's a pretty trivial observation (I mean, yeah, it is a lattice after all) without any deep insight, as opposed to the Higgs mechanism for example.
- zarzavat 4y ago
  It’s counterintuitive because most people are more familiar with the mathematical concept of symmetry whereby a lattice has more symmetry than a random set of points (which almost certainly has no symmetry at all). However from the physics point of view, the random set of points is more symmetrical than the lattice because there’s no way of telling which way a random set of points is oriented.

hangonhn 4y ago

In case anyone else is as confused about time crystals as I was, Physics Girl recently released a video on YouTube that does a decent job of explaining it: https://www.youtube.com/watch?v=ieDIpgso4no https://www.youtube.com/watch?v=ieDIpgso4no

moffkalast 4y ago

> time crystals, which are strange quantum systems that are stuck in an endless loop to which the normal laws of thermodynamics do not apply And here I was thinking they were talking about crystal oscillators.

mensetmanusman 4y ago
Replace ‘time crystals’ with MS Windows
- deleted 4y ago
  [deleted]
cpncrunch 4y ago
It sounds like it's not really a "crystal" as such. I wonder if the person who came up with this term was a scifi fan. It sounds like the kind of thing that would be in Dr Who or Star Trek.
- userbinator 4y ago
  It reminded me of https://en.wikipedia.org/wiki/Time_Cube https://en.wikipedia.org/wiki/Time_Cube
- euroderf 4y ago
  Dilithium is just a quark-boson metacrystal, don'cha know.

drc500free 4y ago

This article perfectly bookends my abandoned physics degree. 1. This reminds me a bit of the delayed-choice quantum eraser, which is one of the weirdest scientific outcomes and is the sort of thing that inspired me to pursue a physics degree. It implies a certain kind of time travel is possible, in the sense that in the present moment we can cause some past moments to collapse. 2. As my TA, Frank Wilczek successfully scared me off that physics degree by simply being so smart and having complicated things come so easily to him. Being confronted with the kind of horsepower needed to be successful in academic physics was eye-opening.

quickthrower2 4y ago
2. Seems sad to me, his job was to make sure you are inspired, or at least informed to make a wise choice, but not scared off. But maybe he didn't know.
- taneq 4y ago
  Sounds like “informed to make a wise choice” still applies? I had a similar experience with mathematics, having been “good at maths” in high school and then making friends in university with people who are ACTUALLY good at maths.
- drc500free 4y ago
  He definitely didn't know (he was just excited about showing us Einstein summation notation), and he definitely informed me to make a wise choice. Not every degree program is about ensuring the best median performance, some are only concerned with picking out the world-changers. And that's okay.
  - bognition 4y ago
    As a disillusioned phd I appreciate your response here. For years I’ve beaten myself up for not doing noteworthy science. For some reason your words have washed away a lot of guilt.
    - 4y ago

V__ 4y ago

Coincidentally, I came across a video today which describe in laymen terms what time crystals are: https://www.youtube.com/watch?v=ieDIpgso4no https://www.youtube.com/watch?v=ieDIpgso4no tl;dw: Crystals are materials which atoms or molecules are aranged in a repeating manner. Time crystals are a material which isn't just repeating in the three dimensions of space but also in the "time dimension". Basically, the quantum spin of the material switches regularly, even though no energy is being applied.

jthrowsitaway 4y ago
Thanks, but I couldn't watch more than 30 seconds of that video. The cuts every 3 seconds or when the speaker took a slight pause is maddening.

paraiuspau 4y ago

Uncle Rico can finally go back and take State.

zackees 4y ago

Time crystals should be called Perpetual resonance waves in a bose-einstein condensate.

jagged-chisel 4y ago

This is why browsers have reader mode.

deleted 4y ago

[deleted]

Technetium 4y ago

Physics Girl did a fantastic video explaining this in layman's terms: https://www.youtube.com/watch?v=ieDIpgso4no https://www.youtube.com/watch?v=ieDIpgso4no (4:55-6:49 is a sponsor)