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Google Science

A Time Crystal Finally Made Real (quantamagazine.org) 69

Posted by msmash from the closer-look dept.
In a preprint posted online Thursday night, researchers at Google in collaboration with physicists at Stanford, Princeton and other universities say that they have used Google's quantum computer to demonstrate a genuine "time crystal" for the first time. From a report: A novel phase of matter that physicists have strived to realize for many years, a time crystal is an object whose parts move in a regular, repeating cycle, sustaining this constant change without burning any energy. "The consequence is amazing: You evade the second law of thermodynamics," said co-author Roderich Moessner, director of the Max Planck Institute for the Physics of Complex Systems in Dresden, Germany. That's the law that says disorder always increases.

Time crystals are also the first objects to spontaneously break "time-translation symmetry," the usual rule that a stable object will remain the same throughout time. A time crystal is both stable and ever-changing, with special moments that come at periodic intervals in time. The time crystal is a new category of phases of matter, expanding the definition of what a phase is. All other known phases, like water or ice, are in thermal equilibrium: Their constituent atoms have settled into the state with the lowest energy permitted by the ambient temperature, and their properties don't change with time. The time crystal is the first "out-of-equilibrium" phase: It has order and perfect stability despite being in an excited and evolving state. "This is just this completely new and exciting space that we're working in now," said Vedika Khemani, a condensed matter physicist now at Stanford who co-discovered the novel phase while she was a graduate student and co-authored the new paper.
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A Time Crystal Finally Made Real More

A Time Crystal Finally Made Real

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  • More accurate to say successfully simulated... (Score:5, Informative)

    by SuperKendall ( 25149 ) on Friday July 30, 2021 @02:11PM (#61639201)

    When I read "real" I thought they had produced a physical time crystal.

    In fact not; what they have done though is still really impressive - they have simulated a real time crystal that could work.

    So the summary headline is a bit misleading on this.

    Will be interesting to see if someone can truly produce a real, physical time crystal...

    • I could be wrong but from my understanding of the article, they produced a real time crystal out of the qubits in a quantum computer. It's not computing a simulation of a time crystal, it is one. It just happens to be made of qubits.

      • Well, except it's not as if the quantum computer itself isn't consuming energy - which seems to be an underlying fundamental flaw in this claim.

        • Re: (Score:2)

          by spun ( 1352 )

          But is it? Is it really "on" or are they just tuning the qubits and then turning off the power? I mean, it's not totally clear from the article. Either of us could be correct.

        • Re: (Score:2)

          by ffkom ( 3519199 )
          Indeed, using a huge apparatus that requires lots of energy for cooling alone and has many cables going in and out for all sorts of signals make this not so much a demonstration of "a thing that is a time crystal" - where one would expect to have some item sit well isolated in a vacuum chamber, and by careful observation you can sense repeating pattern of changing attributes.

          Whether their apparatus just reproduced or simulated aspects of a time crystal, rather than being one, is far from being verifiable

      • Maybe so... (Score:3, Interesting)

        by SuperKendall ( 25149 )

        I could be wrong but from my understanding of the article, they produced a real time crystal out of the qubits in a quantum computer.

        The part of the article that made me think it was more of a simulation was this paragraph:

        With todayâ(TM)s preprint, which has been submitted for publication, and other recent results, researchers have fulfilled the original hope for quantum computers. In his 1982 paper proposing the devices, the physicist Richard Feynman argued that they could be used to simulate the pa

        • Re: (Score:2)

          by spun ( 1352 )

          Yeah, it's not totally clear and the article is not really well written. Still, sounds like an exciting development in the field of condensed matter physics. And who knows? Someday we may even find a use for the weird little things.

    • Re: (Score:2)

      by chill ( 34294 )

      Worry not. I anticipate a resurgance of neo-hippies and their magic "crystals" bringing alignment to the cosmos -- for a fee. This time, TIME crystals.

      Ex-hippy boomers are about the right age to feel nostalgic for this shit.

  • A novel phase of matter

    I pretty sure this phase of matter has been around before humans discovered it. I noticed that there have been a ton of people contributing to this. Why is Vedika Khemani the only one mentioned by name?

  • The 2nd Law is observational; it doesn't actually say that disorder must always increase. Sometimes the simplified version uses that word, but that is incorrect. What it says is that observationally it has always followed this pattern. Disorder does increase. There is no fundamental reason that entropy has to increase; we've just never seen an example where work is done without waste heat being generated, and we've never seen any circumstance where total heat in the system goes down. So we know that under n

    • The second law states that entropy cannot decrease without work being done on (energy being provided to) a closed system.

      • Irrelevant. Did you have something to say? Figure out how to say it. Otherwise, shut the fuck up.

    • Re: (Score:3, Informative)

      by Anonymous Coward
      The fundamental reason entropy increases is because of the statistics of large systems [wikipedia.org]. This is why violations of the second law are only seen very rarely in very small systems.

    • Re:Remember (Score:4, Interesting)

      by excelsior_gr ( 969383 ) on Friday July 30, 2021 @04:26PM (#61639867)

      Indeed. My thermodynamics teacher at the university was very specific about calling it an "axiom" not a "law" (all of them, in fact, not just the 2nd). He also didn't find it elegant that pretty much all of thermodynamics is based on three unproven axioms (or four, if you count the 0th). He was a proponent of the idea that thermodynamics should be based on as few axioms as possible, because you shouldn't just declare stuff true left and right without rigorous proof. He was therefore a fan of the single-axiom formulation of thermodynamics by Hatsopoulos and Keenan, where all three "standard" laws of thermodynamics can be derived from that one axiom. Needless to say, you had to do a lot of study to pass his class.

    • The 2nd law is not at all what most people think it is. It isn't observational as you say. Neither is it a rigorous theorem. It actually is a definition, but not of entropy or anything like that. The 2nd law of thermodynamics defines the arrow of time. The fundamental laws of nature don't distinguish between past and future. There's nothing special about one time direction to distinguish it as "positive" or "forward". We define the "positive" time direct to be the direction in which entropy increases

    • "The 2nd Law is observational"

      All scientific laws are observational. Sometimes they have a theoretical basis, but that is not necessary to be correct. In fact, a scientific law can contradict a theory without either being incorrect. See for example the law of centrifugal force, which gives you a value for a force that is completely fictitious yet observable.

      • False. A law being observational does not mean that it was arrived at by observation. It means something else.

  • Time cube (Score:3, Insightful)

    by sinij ( 911942 ) on Friday July 30, 2021 @02:24PM (#61639225)
    All this time we have been mocking time cube [2enp.com] guy, it turns out he is right and time can by crystallized (into a cube) ?

    • Re: (Score:3)

      by OzPeter ( 195038 )

      All this time we have been mocking time cube [2enp.com] guy, it turns out he is right and time can by crystallized (into a cube) ?

      Obviously someone finally decided that they should go to Zombocom [zombo.com] where anything is possible and the only limitation is yourself.

    • I've been telling you Sun-Down's with Belly Button-less Mamas that Prof. Ray has been vindicated for-during the Next-Previous 3-Days.

    • All this time we have been mocking time cube [2enp.com] guy, it turns out he is right and time can by crystallized (into a cube) ?

      Wow, this reminds me of the rantings of Terry Davis who wrote TempleOS TempleOS [wikipedia.org].

  • Can a Time Lord (Score:3)

    by IWantMoreSpamPlease ( 571972 ) on Friday July 30, 2021 @02:25PM (#61639231) Homepage Journal

    be far behind?

  • Wow, you've built an oscillator (Score:4, Interesting)

    by wakeboarder ( 2695839 ) on Friday July 30, 2021 @02:29PM (#61639251)

    There is an oscillator in every digital electronic devices (so oscillators don't seem that novel to me). Also all this talk of perpetual motion and running forever, well the device requires a laser and lasers are lossy and require lots of energy.

    • Re: (Score:2)

      by ffkom ( 3519199 )
      It is at least a super-conducting oscillator, that much you have to give them. And superconducting oscillators can oscillate without losing energy, per se.
      • All standard superconducting resonators I know of have a small amount of loss and so would not qualify as a "time crystal". The loss can be 1e-10/cycle, but its still there.

        • Is a loss of 1e-10/cycle consistent with reports of currents in superconductors estimated to persist for >100,000 years?

          https://en.wikipedia.org/wiki/... [wikipedia.org]

          Are these persistent currents just as impressive as "time crystals"?

          • A static persistant current is different from an oscillating current - there are extra loss mechanisms for the oscillating current. (inductance means the voltage isn't zero, and that causes non-superconducting electrons to move and lose energy). I think superconducting resonant circuits rarely get above a Q (cycles to 1/e energy loss) around 10^10, but there could be some lower loss configurations I'm not aware of. That is a big number, but not infinite

  • please clarify (Score:5, Interesting)

    by hdyoung ( 5182939 ) on Friday July 30, 2021 @02:31PM (#61639265)
    I'm physics-trained at the undergraduate level, but then something else beyond. So, not a real physicist here. So, please allow me to paraphrase this. It sounds like this group found a many-bodied quantum state, contained in an energy trap, that's stable and isolated enough that there's no coupling to any thermalizing phenomena - ie no coupling to phonons, photon emission, etc that might bleed off and randomize the energy. At least not in a time-scale relevant to a lab experiment. Under these circumstances, they observed (gasp!) oscillatory phenomena that will persist as long as the isolation is maintained.

    Now, this is cool and all. But I remember my first quantum class discussion an electron in a double-well and the resulting oscillatory behavior. I certainly don't get how this breaks any fundamental time-spatial-symmetry laws. As far as I can tell, they observed.. oscillation in an isolated system. Since it's in a condensed matter state they call it a "time crystal" because it's an extremely cool sounding name. I get it... but is this big news?

    Requesting clarification from someone smarter than me, please.

    • As far as I can tell, they observed.. oscillation in an isolated system.

      If they're observing it, is it isolated? I thought that it couldn't be was a fundamental of QM.

  • The legendary Kronos Stone used by the ancient god of time, Chronos. Has it been rediscovered?

  • Preferably in reference to "a big ball of wibbly-wobbly, timey-wimey... stuff."

  • "The endochronic properties of resublimated thiotimoline"

    all over again.

  • Just sayin' cuz light sabers folks.

  • "The law that entropy always increases—the Second Law of Thermodynamics—holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell’s equations—then so much the worse for Maxwell’s equations. If it is found to be contradicted by observation—well these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I c

  • Computer simulation of "thing" is not "thing" in any way, shape or form.

    Time crystals (i.e., very small perpetual motion machines) have not been made "real".

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