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Japan Science

Entangled Particles Break Classical Law of Thermodynamics, Say Physicists 222

Posted by Soulskill
from the not-in-homer's-house dept.
New submitter Zex_Suik writes "Japanese physicists have used one of Maxwell's thought experiments and the ability to turn information into energy to extract more energy from an entangled system than should be possible according to the laws of thermodynamics (abstract). From the article: 'Imagine two boxes of particles with trap door between them. You want to use the trap door to guide the faster particles into one box and the slower particles into the other. In a classical experiment you would have to measure the particles in both boxes to do this experiment. But things are different if the particles in one box are entangled with the particles in the other. In that case, measurements on the particles in one box give you info about both sets of particles. In essence, you're getting information for nothing. And since you can convert that information into energy, there is clear advantage when entanglement plays a role. That's hugely significant. It means that the laws of thermodynamics depend not only on classical phenomenon and information but on quantum effects too.'"
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Entangled Particles Break Classical Law of Thermodynamics, Say Physicists

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  • I can create something out of nothing ?
    • Re:Soooo (Score:5, Funny)

      by oPless (63249) on Wednesday August 01, 2012 @06:47PM (#40849505) Journal

      Well God did *that* some 6,000 years ago.

      • Re:Soooo (Score:5, Funny)

        by zero.kalvin (1231372) on Wednesday August 01, 2012 @06:50PM (#40849549)
        I'm sorry to be such a grammar freak but you misspelled billion in your comment.
      • Re:Soooo (Score:5, Funny)

        by gd2shoe (747932) on Wednesday August 01, 2012 @07:38PM (#40850109) Journal

        I can create something out of nothing ?

        Well God did *that* some 6,000 years ago.

        According to classical theology, which is totally unsubstantiated by biblical text. Just because it's been taught for more than a thousand years doesn't make it biblical.

        • Re: (Score:2, Funny)

          by Shavano (2541114)

          I can create something out of nothing ?

          Well God did *that* some 6,000 years ago.

          According to classical theology, which is totally unsubstantiated by biblical text. Just because it's been taught for more than a thousand years doesn't make it biblical.

          "Substantiated" by the Biblical text? Somebody mod that Funny.

    • Re: (Score:2, Informative)

      by Anonymous Coward

      Actually that happens all the time. Empty space has energy, and energy and mass are interchangeable. Thus particles pop in and out of existence continuously. http://en.wikipedia.org/wiki/Vacuum_state [wikipedia.org]

      *I'm not a physicist, please don't kill me for getting it completely wrong.

      • by Squiddie (1942230)
        Yes, but I thought the point was that an anti-particle was created at the same time, and so the net was still zero.
        • The trick is getting rid of the anti-particle. Sort of like you get rid of the clam-shell when you buy a yo-yo and thus have a net-positive gain!
      • Re:Soooo (Score:5, Informative)

        by Rei (128717) on Wednesday August 01, 2012 @07:59PM (#40850349) Homepage

        This isn't about antiparticles; it's about information being exchangeable for energy.

        This is really fascinating in that they've actually implemented Maxwell's Demon. A bit of backstory: Maxwell's Demon is a thought experiment about there being two chambers with a tiny, atom-sized demon sitting guarding an atom-sized gate between them. If there's a high-energy particle coming, he open's the gate. If there's a low-energy particle, he lowers the gate. Hence, you end up doing work (pumping heat) without a relevant source of energy (since there's no realistic constraints on the mass of the demon or the gate, they can be discounted). Entropy is going in the wrong direction. The question is: would such a thing work, violating the laws of physics, and if not, why?

        The solution was that to know when to open the gate, the demon would have to measure the incoming particles. And it turns out that the entropy change involved in the measurement is more than the gain from what the demon is doing. But then later a hole in this argument was pointed out: if you have information on quantum states stored in a "memory", the demon doesn't need to measure the particles. But since memory can't be infinite, at some point you must cause the entropy change that the information storage is hiding. Information is basically acting as a form of energy.

        Here, from the sound of it, they've actually implemented that in the real world, which I find just fascinating.

        • by TaoPhoenix (980487) <TaoPhoenix@yahoo.com> on Wednesday August 01, 2012 @08:29PM (#40850585) Journal

          And with our love of all things military, what would an Information Bomb look like? It took Einstein to barely get us to believe Mass to Energy. Information to Energy just has a whole other creepy ring to it.

          Since we and the **AA have had fun lately with modern topics in Information, I'll even let the Copyright problems (!!) go for now - how many conversion does it take to convert information from a safe source to a bomb? With the obligatory facetiousness, could someone build a bomb out of a Justin Bieber MP3?

        • Re:Soooo (Score:5, Interesting)

          by nebosuke (1012041) on Wednesday August 01, 2012 @10:22PM (#40851397)

          According to my understanding of the article (IANAP), this has nothing to do with memory, and use of memory would not impact the system in any significant way in any case (the initial energy required to take the measurements to store into memory would offset the reduction in entropy during the experiment).

          The fundamental issue with the classical scenario of Maxwell's Demon is that in order to know if/when to open/close the gate you need to measure each particle in the system at least once. The number of measurements >= The number of particles. The basic implication is that you introduce entropy via taking measurements at least as much as you reduce it via segregating particles according to energy differential.

          If you consider quantum entanglement, however, the rule that number of measurement >= the number of particles is no longer necessarily true. E.g., if each particle in the system is entangled with another particle in the system, the number of measurements could be as low as 1/2 the number of particles since one measurement gives you information about both of the paired particles. It is also possible for more than 2 particles to be entangled, so to generalize, you could have N-way entanglement between sets of particles in the system, and the minimum number of measurements becomes number of particles / N.

          The fundamental question I have is if it's possible to determine entanglement relationships between particles in the system for less energy than independently measuring each particle. If not, then you offset the entropy reduction of only measuring one particle from each entangled set by the energy required to identify entanglement relationships.

          • by InterGuru (50986)

            In real life, the entangled states would be broken as particles in thermal motion collided with each other.

          • by Rei (128717)

            The fundamental question I have is if it's possible to determine entanglement relationships between particles in the system for less energy than independently measuring each particle

            Whether you're measuring an entangled particle or the particle itself, it fundamentally requires more energy than you gain by operating the demon. It makes no difference whether entangled or not.

      • Re:Soooo (Score:5, Funny)

        by MobileTatsu-NJG (946591) on Thursday August 02, 2012 @12:01AM (#40852059)

        *I'm not a physicist, please don't kill me for getting it completely wrong.

        If we come after you, close your eyes. We wouldn't want you affecting the outcome.

    • No. It's already there, you just didn't see it.

    • Yes, but the capital gains taxes will kill you.

    • by fm6 (162816)

      Not out of nothing, out of less than you should have put in. It's the difference between a cheap lunch and a free one.

  • by PaulBu (473180) on Wednesday August 01, 2012 @06:46PM (#40849483) Homepage

    ... beforehand to entangle particles? And then put one from each pair into separate boxes?

    Something tells me that energy conservation still holds...

    Paul B.

    • According to TFA, the particles are already in an entangled state.
    • by Old Wolf (56093)

      Something tells me that energy conservation still holds...

      I don't think there's any suggestion that energy conservation is being violated. TFA is extremegly vague, but as far as I can tell, the suggestion is that there is some entropy in entanglement. Can anyone find a more detailed writeup?

    • by Shavano (2541114) on Wednesday August 01, 2012 @08:07PM (#40850391)
      Yep. Something was not included in the math. Also missing: a plausible means of entangling a boxfull of particles and a plausible means of using the entanglement to harvest energy. But aside from the mathematical sleight of hand and the unphysicality, everything looks legit.
    • by sp332 (781207)

      Since you're not *un*-entangling the particles during the experiment, the energy used to entangle the particles shouldn't matter. Besides, they're not talking about a specific amount of energy, they mean there is a technique to sort *all* of the higher-energy particles into one side of the box. That means you can extract some energy from the diffusion when the particles re-randomize, and then do it all over again to collect (over time) an unbounded amount of energy.

      • If the particles are entangled, measuring the one should also alter the other.

              Brett

      • by epine (68316)

        Stupid physicists. The given information (which particles are entangled) is a thermodynamic asset. I guess they decided not to count this, since there isn't an experiment (which I'm aware of) to test particles for entanglement. I think you have to know they were stamped out with the same vintage code.

        This whole thing smells more of violating presumptive accounting categories than real physics. But then I'm an even stupider arm-chair physicist.

        • by jamesh (87723)

          This whole thing smells more of violating presumptive accounting categories than real physics. But then I'm an even stupider arm-chair physicist.

          So the Enron guys became physicists and think they can fudge the books of nature?

    • Agreed, seems like a total logic failure. I am quite certain at this point the amount of energy required to entangle particles is quite steep, as well as corralling them into whatever 'box' you're using.

      Keeping them in that 'box', and keeping them from losing their entanglement will also cost them energy, and then I would bet the 'information' gleaned about the paired particle is not 100% accurate, as some particles would inevitably fail to pair or lose their pairing.

      Also, when talking on the submicroscopic

    • by khallow (566160)
      This might be the thought experiment that demonstrates your intuition.
    • by mwvdlee (775178)

      They may have had to spend energy to entangle the particles, but this by itself is meaningless unless you know where this energy is after the experiment.

  • by Lord Lode (1290856) on Wednesday August 01, 2012 @06:47PM (#40849515)

    So you have two particles which are entangled. One is moving fast, one is moving slow. You measure one, and you then get the speed of *both*? How does that work? Does the measurement instrument have two dials?

    Also, maybe the entanglement itself is worth the extra energy :)

  • Article title (Score:5, Informative)

    by Old Wolf (56093) on Wednesday August 01, 2012 @06:48PM (#40849521)

    doesn't seem to match the rest of the article. TFA talks about how they can extract more usable energy from the system using entanglement, but it doesn't violate any physical laws. The only violation is in the title!

    • by mrstrano (1381875) on Wednesday August 01, 2012 @07:00PM (#40849681) Homepage

      Physical laws only apply in TFA, titles exist in a parallel universe where physics does not have strict laws and the only thing that matters is clicks.

      • by Odin's Raven (145278) on Wednesday August 01, 2012 @08:09PM (#40850405)

        Physical laws only apply in TFA, titles exist in a parallel universe where physics does not have strict laws and the only thing that matters is clicks.

        But as we know from basic Slashdot theory, the title and TFA are entangled at the point of publication - the so-called "quantum firehose phenomenon". Just look at the number of people who, from examining the title alone, are able to determine the article's content in sufficient detail to completely refute it without having read a single word. This is, of course, the real-world equivalent of Gallagher's Watermelon, which as we all know is based on the classic deiknymi (the ancient Greek term for "dessert") or gedankenexperiment (German, literally "seed spitting contest") in which a watermelon is put inside a box with a Geiger counter, a vial of Roundup, and a small sample of radiactive material, the contents of which become irrelevant once you hit them repeatedly with a sledgehammer. It doesn't really have much to do with science, but it's quite a lot of fun.

    • Re:Article title (Score:4, Informative)

      by Baloroth (2370816) on Wednesday August 01, 2012 @10:02PM (#40851273)

      The title is technically accurate (misleading as hell, but accurate): you can, indeed, get more energy from a system than predicted by the classical law of thermodynamics. You just have to extend the law to include the energy bound in the quantum entanglement, which classical thermodynamics does not.

  • by v1 (525388) on Wednesday August 01, 2012 @06:51PM (#40849565) Homepage Journal

    I get how two different entangled particles can share behavior, and how you can check one to test the other, but why don't things that affect one particle cause the entangled particle to also be affected?

    And the other question I had on this is with the Brownian Motion. When you throw up a barrier to stop a particle from moving, and it hits the barrier, isn't that newton's 3rd law at work? Both deflecting the particle and providing equal but opposite energy to the barrier? How is this accounted for in this conservation of energy model? That would seem to be the missing input of energy?

    Lets say that little invisible demon gets knocked back a little by the deflection of the particle. He eventually has to reposition himself back where he was, in front of the door. That requires energy. And I think there is where we are adding energy into the system that we think we're getting for "free".

    (I'm no quantum mechanic, I only work on Fords)

    • by Smallpond (221300) on Wednesday August 01, 2012 @07:09PM (#40849811) Homepage Journal

      Q. Where do you get Maxwell's demon?
      A. Monster.com

      • by Chemisor (97276) on Wednesday August 01, 2012 @08:03PM (#40850369)

        > monster.com

        Job title: Maxwell's demon

        Job description: evaluates energy of subluminal particles. Makes time-critical decisions and pass/fail determinations on them. Operates retractable gate assembly. Supervises particle passage through the gate. Maintains the integrity of the gate assembly through preventive maintenance.

        Job requirements: Ph.D. in Physics with 15 years of experience specializing in quantum mechanics and entanglement. At least 10 years of industry experience with retractable gates. Minimum 12 years of experience required with FPGA controller development and .NET programming. Must be able to make quick decisions under pressure (23 kPa or higher) and possess excellent interpersonal communication skills. Must be able to repeatedly lift up to 34 ng.

        Compensation: 42 kJ/hour

    • by Rei (128717)

      Work (change in energy) is force times distance. The barrier is not moving, hence, no work is being done to it, any more than you standing on the floor is doing work to it because of gravity. The particle is retaining its kinetic energy, just redirecting it - again, no change in energy. The energy input comes in from Brownian Motion - the heat (motion) of the particles on which the particle is intercting. But that's seemingly a violation of the 2nd law at hand. The missing piece of the picture is the e

      • by v1 (525388)

        The barrier is not moving, hence, no work is being done to it,

        To block something, you have to have an interaction with it. And then we have newton's first law. The barrier may not move, but somehow some way there is a change in energy in the barrier. Temperature, orientation, location, etc.

        If I run my truck into a brick wall and the wall doesn't move, it doesn't mean I had no affect on the wall. At the very least, I created sound, heat, cracked some bricks, and broke some mortar free of bricks.

        Althoug

        • by raehl (609729)

          If I run my truck into a brick wall and the wall doesn't move, it doesn't mean I had no affect on the wall. At the very least, I created sound, heat, cracked some bricks, and broke some mortar free of bricks.

          Depends on the strength of the wall.

          You may have just REALLY screwed up your truck. (The collision might also very slightly affect the rotation of the planet, but less than you affected the rotation when you were accelerating the truck in the first place.)

        • by Rei (128717)

          It is not inherent that you "create sound, heat, crack bricks, and break mortar free of bricks" in a nanoscale collision (akin to the collisions constantly occurring under your feet when you stand). Collisions at the atomic level can be (and usually are) 100% elastic. The impact is changing the kinetic energy of the particle into bond strain in the wall, which then springs back with no generation of heat or other loss unless it was a very high velocity impact.

    • Re: (Score:3, Funny)

      by Greyfox (87712)
      I think it works more like ebola. Lets say I give some guy ebola. Then he bumps into you. Then I test him and find out he has ebola. Now I know you also have ebola. If I shoot him at this point, that doesn't affect you. You're still just out there putting your ebola in everyone. See where I'm going with this? The entanglement is ebola! You now have to find and shoot both particles before everyone's wandering around with ebola! Get to it!
  • No information is gained, for the same reason that separating entangled particles by a great distance and then measuring one doesn't result in information traveling faster than the speed of light.

    This is like saying putting a red ball in one bag and putting a blue ball in an identical bag, then shuffling the bags around, then looking in one bag gives you free information about the other bag. It doesn't.

    • by v1 (525388)

      looking in one bag gives you free information about the other bag

      I think his point there was you paid for information about the one bag, and that your ability to infer the other information as a result means you got it for "free". Which I agree, is wrong. You always knew that the bags contained different balls. So no new information was gained, just clarification of existing information.

      It's like me giving you one more number for your Sudoku puzzle and your then being able to solve the entire puzzle, all

      • by Brad1138 (590148)
        I have a problem with the "info is energy". If I tell you my toe hurts, exactly what energy can you get from that?
        • Could you tell me that without increasing the entropy of the universe?
        • by gagol (583737)
          You just need to scream very loudly (think dilbert's annoying coworker) and stand in front of a small wind turbine!
        • when you fill up a balloon, what are you doing? (imagine you keep temperature constant via some mechanism), what you're doing is confining air molecules inside the balloon---increasing information (you know where those molecules are [inside the balloon], you're lowering their entropy).

          again, keeping temperature constant, release some air out of the balloon, having it do some work. You've just converted that information (losing knowledge of where air molecules are---increasing entropy) into work.

          the trick ab

          • by Brad1138 (590148)
            Don't take this personally, but that is one of the biggest loads of crap I have ever heard. Basically taking 2 non-related things, poorly trying to connect them together, to bolster a theory.

            We all take for granted that (essentially) energy can not be created or destroyed. I did not loose any energy from that statement (my balloon didn't deflate), so no one could have gained any. I am not a Physicist or anything, but a life long science geek with a fairly mathematical/scientific mind. That is some off t
    • Re:Fail (Score:5, Interesting)

      by Old Wolf (56093) on Wednesday August 01, 2012 @07:12PM (#40849847)

      No information is gained, for the same reason that separating entangled particles by a great distance and then measuring one doesn't result in information traveling faster than the speed of light.

      This is like saying putting a red ball in one bag and putting a blue ball in an identical bag, then shuffling the bags around, then looking in one bag gives you free information about the other bag. It doesn't.

      Not quite. The latter scenario is affectionately called "Bertlmann's socks"; once you separate the bag, it's true that one has the red ball and one has the blue ball but we don't know which until we look.

      However, with a pair of entangled particles of spin state (up + down) for example, it's not the case that one is up and one is down. If you measure one particle in the "east" direction and find that it is pointing east, then the other one will be found to be pointing "west". It's been proven (Bell's inequalities etc.) that there is no possible "hidden state" that would account for the fact that the two measurements can be taken in arbitrary directions and still correlate.

      • And still you get no free information.
        Since the particles are entangled you already know that their states are related. You can look at one and know the state of the other, but this information isn't free, it's accounted for when you entangle the particles.

      • Re:Fail (Score:4, Interesting)

        by ceoyoyo (59147) on Wednesday August 01, 2012 @08:21PM (#40850525)

        "that there is no possible "hidden state" that would account for the fact that the two measurements can be taken in arbitrary directions and still correlate."

        Not quite. Bell's theorem, and the experiments inspired by it, suggest that any classical theory (or hidden variable theory) would have to be non-local. The non-locality can be quite mild though.

        Also, both the results of the experiments that show Bell's inequality is violated, and the theorem itself, are being challenged.

        • by Old Wolf (56093)

          Also, both the results of the experiments that show Bell's inequality is violated, and the theorem itself, are being challenged.

          Usenet post "LOAL BELL AND EINSTEIN WERE WRONG truthfully in the 24 dimensions of te quantum pie blaaa.." doesn't count

  • by Sebastopol (189276) on Wednesday August 01, 2012 @06:56PM (#40849627) Homepage

    Just sayin', before they start publishing data they should check their cables. /ducks

  • What about the energy you need to spend in order to entangle these particles? Or it comes for free? Like the beer? Oh, never mind, keep swimming...
  • Can I break thermodynamics with a lucky guess?

  • by Commontwist (2452418) on Wednesday August 01, 2012 @07:21PM (#40849931)

    If you make it can you break it? IE. If you can 'make' energy this way then can you 'unmake' it?

    • by Snard (61584)

      If you make it can you break it? IE. If you can 'make' energy this way then can you 'unmake' it?

      If you break it, you bought it.

  • by Tablizer (95088) on Wednesday August 01, 2012 @07:22PM (#40849941) Homepage Journal

    a cat somewhere dies to compensate. It all adds up.

    • by Longjmp (632577)

      a cat somewhere dies to compensate. It all adds up.

      What really makes me wonder is why you - and Schroedinger - dislike(d) cats.

  • by SoftwareArtist (1472499) on Wednesday August 01, 2012 @08:21PM (#40850535)

    The summary is very misleading. This work is purely theoretical. They have not actually succeeded in doing it, contrary to what the summary would make you think.

    It will be interesting to see whether someone can actually make this work in practice.

    • The summary is very misleading. This work is purely theoretical.

      Indeed. There are now three possibilities:

      1. This work is flawed.
      2. This work is correct in both theory and practice.
      3. This work is correct in theory, but does not work in practice. Researchers will have an interesting time figuring out where the original theory of thermodynamics is flawed. And this will then hopefully lead to a better understanding of our universe.

  • Neato.... what's the theoretical minimum number of joules it takes to represent a bit?
    • by garyebickford (222422) <gar37bic.gmail@com> on Wednesday August 01, 2012 @10:52PM (#40851619)

      Interesting question. I used to ask a related question, "How much does a bit weigh?" I learned a couple of years ago that the proper question is, "What is the area of a bit?" See the Holographic Principle [wikipedia.org], and/or an article in Scientific American two or three years ago. It has to do with the requirement that the Universe can never lose, but must always gain, entropy. When mass is sucked into a black hole, the entropy of the Universe would lose entropy, so the entropy must be left behind at the event horizon. This somehow forces the surface area of the event horizon to expand according to the mass of the black hole. Since mass entropy can be equated to information entropy, after some shenanigans I don't understand, it turns out that the area of one bit is 2x2 planck lengths.

      But I suspect, since that area is related to the mass that has been sucked in, wouldn't that imply that one bit is related to that amount of mass? Which means it is related to that mass, or equivalently that energy. :D I don't think that means that the mass 'represents' one bit though - rather the opposite, one bit represents that amount of mass or energy.

      • by mark-t (151149)
        While it's interesting to know what the area of a bit is, what I'd like to know is the minimum amount of mass or energy that one bit represents.... or vice versa, if that is more applicable.
  • Excellent! Now we have to figure out how to entangle all the information the NSA, CIA, FBI, Dept. of Homeland Security and local police forces have gathered on unsuspecting people and we can have an unlimited source of power. I love it when a plan comes together.

  • by u19925 (613350) on Thursday August 02, 2012 @02:26AM (#40852799)

    You have to know in advance that the particles are entangled. That extra bit of information is needed. Thus when you measure one particle, you do get that extra bit of information about the other particle. So the information about the other particle is not free but is the direct result of the apriori information about entanglement.

  • I haven't read TFA, but it sounds like they rediscovered the Jarzynski (in)equality [wikipedia.org].

    Basically, if you slam a system with a high free energy into a state with a lower free energy, you actually have a chance to get out more work than you should in equilibrium, offset by a chance of getting less. On average, however, the expected work from the system should agree.

    This would appear pathologically in such a small-scale system that is changing states so quickly.

  • So I can free get air-con from an entangled box somewhere on Antartica and heat from an entangled box somewhere in Death Valley. Great!
  • This actually implies that the energy extracted from entanglement is equal to or greater than the energy required to entangle and separate. This doesn't violate classical thermodynamics, because it isn't really a closed system.

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