Slashdot Mirror
Entangled Particles Break Classical Law of Thermodynamics, Say Physicists
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.'"
... beforehand to entangle particles? And then put one from each pair into separate boxes?
Something tells me that energy conservation still holds...
Paul B.
Well God did *that* some 6,000 years ago.
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 :)
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!
I'm sorry to be such a grammar freak but you misspelled billion in your comment.
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)
I work for the Department of Redundancy Department.
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.
Just sayin', before they start publishing data they should check their cables. /ducks
https://www.accountkiller.com/removal-requested
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
*I'm not a physicist, please don't kill me for getting it completely wrong.
Yes, but the capital gains taxes will kill you.
Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
If you make it can you break it? IE. If you can 'make' energy this way then can you 'unmake' it?
a cat somewhere dies to compensate. It all adds up.
Table-ized A.I.
Yes, but I thought the point was that an anti-particle was created at the same time, and so the net was still zero.
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.
I won't join Slashcott. OTOH, If Beta goes live, I just won't be back until it's fixed. Sorry Dice.
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.
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!
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.
The chloride owes the sodium money.
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.
Yes, so long as you fix it afterwards.
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.
"I'm too busy to research this and form an educated opinion, but I do have time to tell everyone my uninformed opinion."
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?
My first Journal Entry ever, in 8 years! http://slashdot.org/journal/365947/aphelion-scifi-fantasy-horror-poetry-webzine
TFA talks about "Entangled Particles" breaking the law of thermodynamics, seemingly getting something out of nothing
I am not good at all on particle physics, but I believe that particles in their ordinary state do not come "entangled", right?
So, in order to get particles that are already in the "entangled" state, something must have happened to ordinary particles, first, right?
If so, what's the cost (in term of energy) to get originally un-entangled particles to be "entangled"?
Muchas Gracias, Señor Edward Snowden !
it is called 4chan
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
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.
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, 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.
It's easier to be a result of the past, but more fun to be a cause of the future! http://www.spacefinancegroup.com/
Thought Experiment
In real life, the entangled states would be broken as particles in thermal motion collided with each other.
Information has no place in physics?! Are from the 1950s or something? You might like to take a look at some papers by Stephen Hawking on the black hole information paradox. Or, perhaps more directly to the point and more accessible, see if you can figure out what the Wikipedia article on "Physical information" is about.
*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.
"I like to lick butts!" by MobileTatsu-NJG (#32700246) (Score:5, Informative)
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.
Creates world 6000 years ago
Spreads lots of clues that something else happened instead (fossils, C14 dating, star light already travelling towards us, etcetera)
Reveals himself only to a dozen or so people
Sends you to hell if you don't believe in him
Troll level: God
My first program:
Hell Segmentation fault
God hasn't even created the world yet, but he will have by the time you finished reading this post.
You aren't even reading it; you'll just falsely remember reading it.
Slashdot social media options: AIM, ICQ, Yahoo, Jabber and Mobile Text. Why no MySpace?
Which gravitational law are you talking about? Quantum gravity or General relativity
No mention of hell in the Bible? Informative? Seriously?
But the fearful, and the unbelieving, and the abominable, and murderers, and whoremongers, and sorcerers, and idolaters, and all liars, will have their part in the Lake burning with fire and brimstone, which is the second death.
-Revelations 21:8
That's not hell; that's New Jersey.
Orwell: "In a Time of Universal Deceit, telling the Truth is a Revolutionary Act"