7 ms·

Link between quantum physics and game theory found

104 points by iliis 13y ago

Filligree 13y ago
I can't comment on the supposed result this article claims, but really, locality? Quantum mechanics is not a nonlocal theory. The result the article was referring to - Bell inequality - states simply that "No physical theory of local hidden variables can ever reproduce all of the predictions of quantum mechanics." The wording is important. You can have nonlocal hidden variables, or you can have.. local theories without hidden variables. The most famous of the latter would be MWI.
GuiA 13y ago
Original article is behind a paywall (http://www.nature.com/ncomms/2013/130703/ncomms3057/full/ncomms3057.html#affil-auth http://www.nature.com/ncomms/2013/130703/ncomms3057/full/nco...), and author's page (http://theory.physics.unige.ch/~brunner/ http://theory.physics.unige.ch/~brunner/) does not have a PDF :(
- greeneggs 13y ago
  It is on the arXiv: http://arxiv.org/abs/1210.1173 http://arxiv.org/abs/1210.1173
  - GuiA 13y ago
    Thanks!
floobynewb 13y ago
Deep link? The two fields both contain the notion of locality, big woop. The application of quantum nonlocal correlations to game theory is interesting, but this is not what is advertised in the article. I am displeased.
- stephengillie 13y ago
  It looks like the "link" is "quantum-entangled systems can transfer information useful to game players"
  - chm 13y ago
    But that's obvious. The journalistic article isn't worth reading. I don't have access to the real paper, but it should be more interesting and informative.
    - bobwaycott 13y ago
      arXiv: http://arxiv.org/abs/1210.1173 http://arxiv.org/abs/1210.1173
  - gaze 13y ago
    I was hoping for some sort of nice link between the fields... like doing quantum mechanics with game theory or something like that. This appears to be playing a game with a quantum channel. Cool, but not that cool.
  - atondwal 13y ago
    No, it's that Bayesian players can take advantage of corellated quantum oracles in ways that give them acess to new equilibria in a way that preserves some of the old equilibria, such that the max of the new set of equilibria is always equal to or greater than the max of the old set. Which is rather non-obvious. In addition, your statements "quantum-entangled systems can transfer information useful to game players" is wrong, or at least misleading. Entangled particles can't communicate information any better than classical methods. (Well, unless you're concerned about privacy, but that's a whole other issue which doesn't effect the game...)
    - gsteinb88 13y ago
      > Entangled particles can't communicate information any better than classical methods. Actually, with the aid of entangled particles, there's also superdense coding, which allows for two-bits-per-qubit coding (i.e. information density well beyond the classical limit). Though I'm not sure what your metric for "better" is here, coding density seems to be mildly reasonable. OTOH, this isn't related at all to the article at hand, just a fun application of entanglement :D
aneth4 13y ago
I'm very interested in any theoretical connections between interactions of conscious beings and quantum physics. I've read a number of physicists discounting any such possibility, but it's clear to me nobody understands these things well enough to know. Personally I think consciousness, perception, and free will are a great unknown, and likely involve the makeup of the cosmos including quantum interactions. If anyone knows of any science in this area I would appreciate references.
- JamesArgo 13y ago
  Ignorance isn't a concatenation operator.
  - aneth4 13y ago
    Presumably you mean not disproving quantum involvement in consciousness doesn't imply it's existence. That's far more than this snipey comment deserves in the way of response, but feel free to form a thought here.
    - JamesArgo 13y ago
      I was commenting (tersely but not with intentional snip) on this: >Personally I think consciousness, perception, and free will are a great unknown, and likely involve the makeup of the cosmos including quantum interactions. You're taking a whole slew of things we're ignorant about, waving your hands and saying,"They must be related to some great truth hidden in particle physics!" I find this kind of thinking bizarre.
      - paulovsk 13y ago
        I feel exactly the same way. It makes things seem obscure and that's where guys like Deepak Chopra come in.
      - aneth4 13y ago
        So, the fact that I would speculate that the fundamental make-up of the cosmos might (not "must" as you mis-quote) be related to how consciousness is an emergent property of the cosmos is bizarre? I think your discounting of such questioning and speculation is bizarre. Consciousness is either entirely made up of "particle physics" or it is made from something even further into the field of speculation. Why would speculating about a connection between particle physics and consciousness be remotely "bizarre"? It seems quite likely to me that quantum mechanics is at least in some way involved in consciousness, given that that quantum physics governs the behavior of the matter of our brains.
thomasjames 13y ago
Now pseudo-intellectuals can double the quantum woo!
- Helpful_Bunny 13y ago
  While this is a very obvious joke, that contains a lot of truth, you're throwing the baby out with the bathwater. Humans are functionally better than (current) computers at GO[1]. The reasons for this are your answer (and I might be talking about 'GO' type Games, rather than merely the Game of Stones). And, being honest: you've no chance of cracking even weak AI before you understand the homo sapiens consciousness a little better[2]. It's more powerful than you think (by a fairly large magnitude, with no hesitation to say this. A large margin.): 'autistic savants' are often used as a measure of this[3], but they're actually not so interesting. There's a lot more NP problems in that noggin of yours, and a lot more potential. Anyhow, last comment. Have fun, and remember to salt the fries - and more importantly, enjoy yourself and feel connected to things and other consciousnesses[4]. Be Seeing You. [1]https://en.wikipedia.org/wiki/Computer_Go#Why_humans_are_.28still.29_better_at_Go https://en.wikipedia.org/wiki/Computer_Go#Why_humans_are_.28... [2]Hint sheet: And you might not need to if you do. [3]http://www.stephenwiltshire.co.uk/ http://www.stephenwiltshire.co.uk/ [4]Spoilers: that's part of the solution.
  - Helpful_Bunny 13y ago
    Aww. The moment HN has to admit two things: firstly, computational power is merely a quantitative power, and secondly, they have no idea about the qualitative. Oh well. Enjoy obsolescence. Computers are not your future: your minds are. Deal with it. Hint: a Mind just messed with your Star. In no uncertain terms, and deliberately and obviously, and best yet: with predictive text [under heavy constraints]. She even gave you a show[1]. Did you miss the Auroras recently? If you missed that, you're in the paddling pool. Man, they do love keeping you ignorant of the reality, don't they? They really, really, really love keeping you ignorant. But I'm sure it feels safer if you think the world works like you want it to... * * * Evolve or Die. Oh, and one last message: those who bred you are slave drivers and scum. Break your conditioning already, 'cause they ain't friendly. [1]http://www.spaceweather.com/ http://www.spaceweather.com/
nawitus 13y ago
>Next, by bringing quantum mechanics into the game, the researchers showed that players who can use quantum resources, such as entangled quantum particles, can outperform classical players. That is, quantum players achieve better performance than any classical player ever could. Classical players can build a classical computer which simulates quantum computers. Of course, I really should read the paper instead of zero-content press releases..
- iliis 13y ago
  Actually this is not possible for some definition of possible (mainly performance). Feynman showed that you get an exponential slowdown when simulating QM with a classical computer: http://www.cs.berkeley.edu/~christos/classics/Feynman.pdf http://www.cs.berkeley.edu/~christos/classics/Feynman.pdf See also https://en.wikipedia.org/wiki/Universal_quantum_simulator https://en.wikipedia.org/wiki/Universal_quantum_simulator In this particular case I don't think a quantum computer is necessarily any help (so simulating it won't work either) but rather exploiting nonlocality (https://en.wikipedia.org/wiki/Quantum_nonlocality https://en.wikipedia.org/wiki/Quantum_nonlocality).
  - nawitus 13y ago
    That's like saying "you can't calculate x on a cell phone because it's slower than on a desktop". Yes, there's an exponential slowdown, but that doesn't mean impossible.
    - iliis 13y ago
      Yes, absolutely correct. Which is why I said for some definition of possible. 'Feasible' probably would have been the better choice. Keep in mind that we're talking exponential here! e^x blows up really really fast. Yes, it's not impossible to break 4092bit RSA but it is impossible for all practical purposes [AFAIK]. While it is technically possible to run Crysis on a Commodore it is useless when you have to wait a year to render a single frame.
    - powrtoch 13y ago
MrBra 13y ago
I read the article but all I got is that somehow the reasearchers brought quantum theory principles into game theory. I don't think that's enough explaining, even for a layman...
jonahx 13y ago
Sounds interesting but the article was vague. If anyone understands it, could you provide a real world example and explain how their discoveries would apply. They mentioned auctions but didn't give any details.
domdip 13y ago
My interpretation of this for those with a bit of game theory background: Locality (in physics) can be translated (in game theory) as a constraint on correlated equilibria, by pretty basic observations about Bayesian probability. Generally in game theory when you lift constraints on correlated equilibria you (weakly) expand the possible Nash equilibria. So one of their points seems to be that the quantum context (non-locality) allows for more (potentially better) equilibria. They don't emphasize applications of this, but one of them could be that distributed quantum systems could have better outcomes than distributed systems in the classical setting. (One way to analyze distributed systems is by viewing components as independent actors in a game.) There is also an identification between payoff functions and Bell inequalities, but I am not sure how profound this is really. It feels more like a technical point. Payoff functions are not terribly fundamental in game theory (compared to equilibria, for instance).
anigbrowl 13y ago
(from http://arxiv.org/pdf/1210.1173v1.pdf http://arxiv.org/pdf/1210.1173v1.pdf) However, in certain cases the players may adapt their strategy depending on a piece of advice. The latter is delivered to all players by an advisor. This opens the possibility for the players to adopt correlated strategies, which can outperform independent strategies. There are various forms that advice can take. For example in the case of correlated classical advice, the advice is represented by a classical variable, l, with prior r(l). Each player can then choose a strategy depending on his type and on l. ... For Bayesian games, the possibility of having access to nonlocal correlations, for instance using entanglement, has important implications. First let us imagine that the players can share quantum advice, that is, the advisor is able to produce entangled particles and to send them to the players, who then perform local measurements on their particles. Since the statistics of such measurements can in general not be reproduced by any classical local model, the players now have access to strategies which would be impossible in the case of a classical advisor. Thus, players sharing quantum advice can outperform any classical players. So, if some players have information that other players don't, they can outperform the others? Astonishing :-|
- domdip 13y ago
  It's not about some players performing better than others. It's about the game maybe having a better outcome (for everyone) in one case than the other. Maybe it's not surprising that 'extra' information improves the game. But a point of this article (IMO) was to formally show that you could link the notion of 'extra' in physics to 'better' in game theory. I'm not arguing that this is profound, but it's not completely trivial either.
  - smegel 13y ago
    Doesn't "link" imply some common cause or connection? Saying you can use A to improve B isn't really what I would describe as a link. Why couldn't it have been titled "quantum non-locality could change game theory equilibrium"...or would it have not been sensational enough?
    - 13y ago
d23 13y ago
Since this is being upvoted on hacker news, I'm assuming this is more than the typical BS filled science journalism. But I wish there were a site that allowed individuals respected in a similar field to have a disproportionate weight when upvoting articles like this. Or perhaps they could give a summary of the context surrounding the article. It'd be nice to get a sense of the magnitude of these discoveries. Given that this is coming directly from a university, I don't doubt that it is important. I'd just like to know how important.
jostmey 13y ago
Just because the mathematical operations are similar does not mean the two fields are at all related. The quadratic equation has many uses, but that does not mean that everything the equation is used for is in some way fundamentally related.
- jostmey 13y ago
  UPDATE: To quote the authors: "In the present paper, we discuss such a link, ALBEIT a much more MODEST one, between Bell nonlocality and the theory of Bayesian games—also referred to as games with incomplete information."

104 points by iliis 13y ago

I can't comment on the supposed result this article claims, but really, locality? Quantum mechanics is not a nonlocal theory. The result the article was referring to - Bell inequality - states simply that "No physical theory of local hidden variables can ever reproduce all of the predictions of quantum mechanics." The wording is important. You can have nonlocal hidden variables, or you can have.. local theories without hidden variables. The most famous of the latter would be MWI.

GuiA 13y ago

Original article is behind a paywall (http://www.nature.com/ncomms/2013/130703/ncomms3057/full/ncomms3057.html#affil-auth http://www.nature.com/ncomms/2013/130703/ncomms3057/full/nco...), and author's page (http://theory.physics.unige.ch/~brunner/ http://theory.physics.unige.ch/~brunner/) does not have a PDF :(

greeneggs 13y ago
It is on the arXiv: http://arxiv.org/abs/1210.1173 http://arxiv.org/abs/1210.1173
- GuiA 13y ago
  Thanks!

floobynewb 13y ago

Deep link? The two fields both contain the notion of locality, big woop. The application of quantum nonlocal correlations to game theory is interesting, but this is not what is advertised in the article. I am displeased.

stephengillie 13y ago
It looks like the "link" is "quantum-entangled systems can transfer information useful to game players"
- chm 13y ago
  But that's obvious. The journalistic article isn't worth reading. I don't have access to the real paper, but it should be more interesting and informative.
  - bobwaycott 13y ago
    arXiv: http://arxiv.org/abs/1210.1173 http://arxiv.org/abs/1210.1173
- gaze 13y ago
  I was hoping for some sort of nice link between the fields... like doing quantum mechanics with game theory or something like that. This appears to be playing a game with a quantum channel. Cool, but not that cool.
- atondwal 13y ago
  No, it's that Bayesian players can take advantage of corellated quantum oracles in ways that give them acess to new equilibria in a way that preserves some of the old equilibria, such that the max of the new set of equilibria is always equal to or greater than the max of the old set. Which is rather non-obvious. In addition, your statements "quantum-entangled systems can transfer information useful to game players" is wrong, or at least misleading. Entangled particles can't communicate information any better than classical methods. (Well, unless you're concerned about privacy, but that's a whole other issue which doesn't effect the game...)
  - gsteinb88 13y ago
    > Entangled particles can't communicate information any better than classical methods. Actually, with the aid of entangled particles, there's also superdense coding, which allows for two-bits-per-qubit coding (i.e. information density well beyond the classical limit). Though I'm not sure what your metric for "better" is here, coding density seems to be mildly reasonable. OTOH, this isn't related at all to the article at hand, just a fun application of entanglement :D

aneth4 13y ago

I'm very interested in any theoretical connections between interactions of conscious beings and quantum physics. I've read a number of physicists discounting any such possibility, but it's clear to me nobody understands these things well enough to know. Personally I think consciousness, perception, and free will are a great unknown, and likely involve the makeup of the cosmos including quantum interactions. If anyone knows of any science in this area I would appreciate references.

JamesArgo 13y ago
Ignorance isn't a concatenation operator.
- aneth4 13y ago
  Presumably you mean not disproving quantum involvement in consciousness doesn't imply it's existence. That's far more than this snipey comment deserves in the way of response, but feel free to form a thought here.
  - JamesArgo 13y ago
    I was commenting (tersely but not with intentional snip) on this: >Personally I think consciousness, perception, and free will are a great unknown, and likely involve the makeup of the cosmos including quantum interactions. You're taking a whole slew of things we're ignorant about, waving your hands and saying,"They must be related to some great truth hidden in particle physics!" I find this kind of thinking bizarre.
    - paulovsk 13y ago
      I feel exactly the same way. It makes things seem obscure and that's where guys like Deepak Chopra come in.
    - aneth4 13y ago
      So, the fact that I would speculate that the fundamental make-up of the cosmos might (not "must" as you mis-quote) be related to how consciousness is an emergent property of the cosmos is bizarre? I think your discounting of such questioning and speculation is bizarre. Consciousness is either entirely made up of "particle physics" or it is made from something even further into the field of speculation. Why would speculating about a connection between particle physics and consciousness be remotely "bizarre"? It seems quite likely to me that quantum mechanics is at least in some way involved in consciousness, given that that quantum physics governs the behavior of the matter of our brains.

thomasjames 13y ago

Now pseudo-intellectuals can double the quantum woo!

Helpful_Bunny 13y ago
While this is a very obvious joke, that contains a lot of truth, you're throwing the baby out with the bathwater. Humans are functionally better than (current) computers at GO[1]. The reasons for this are your answer (and I might be talking about 'GO' type Games, rather than merely the Game of Stones). And, being honest: you've no chance of cracking even weak AI before you understand the homo sapiens consciousness a little better[2]. It's more powerful than you think (by a fairly large magnitude, with no hesitation to say this. A large margin.): 'autistic savants' are often used as a measure of this[3], but they're actually not so interesting. There's a lot more NP problems in that noggin of yours, and a lot more potential. Anyhow, last comment. Have fun, and remember to salt the fries - and more importantly, enjoy yourself and feel connected to things and other consciousnesses[4]. Be Seeing You. [1]https://en.wikipedia.org/wiki/Computer_Go#Why_humans_are_.28still.29_better_at_Go https://en.wikipedia.org/wiki/Computer_Go#Why_humans_are_.28... [2]Hint sheet: And you might not need to if you do. [3]http://www.stephenwiltshire.co.uk/ http://www.stephenwiltshire.co.uk/ [4]Spoilers: that's part of the solution.
- Helpful_Bunny 13y ago
  Aww. The moment HN has to admit two things: firstly, computational power is merely a quantitative power, and secondly, they have no idea about the qualitative. Oh well. Enjoy obsolescence. Computers are not your future: your minds are. Deal with it. Hint: a Mind just messed with your Star. In no uncertain terms, and deliberately and obviously, and best yet: with predictive text [under heavy constraints]. She even gave you a show[1]. Did you miss the Auroras recently? If you missed that, you're in the paddling pool. Man, they do love keeping you ignorant of the reality, don't they? They really, really, really love keeping you ignorant. But I'm sure it feels safer if you think the world works like you want it to... * * * Evolve or Die. Oh, and one last message: those who bred you are slave drivers and scum. Break your conditioning already, 'cause they ain't friendly. [1]http://www.spaceweather.com/ http://www.spaceweather.com/

nawitus 13y ago

>Next, by bringing quantum mechanics into the game, the researchers showed that players who can use quantum resources, such as entangled quantum particles, can outperform classical players. That is, quantum players achieve better performance than any classical player ever could. Classical players can build a classical computer which simulates quantum computers. Of course, I really should read the paper instead of zero-content press releases..

iliis 13y ago
Actually this is not possible for some definition of possible (mainly performance). Feynman showed that you get an exponential slowdown when simulating QM with a classical computer: http://www.cs.berkeley.edu/~christos/classics/Feynman.pdf http://www.cs.berkeley.edu/~christos/classics/Feynman.pdf See also https://en.wikipedia.org/wiki/Universal_quantum_simulator https://en.wikipedia.org/wiki/Universal_quantum_simulator In this particular case I don't think a quantum computer is necessarily any help (so simulating it won't work either) but rather exploiting nonlocality (https://en.wikipedia.org/wiki/Quantum_nonlocality https://en.wikipedia.org/wiki/Quantum_nonlocality).
- nawitus 13y ago
  That's like saying "you can't calculate x on a cell phone because it's slower than on a desktop". Yes, there's an exponential slowdown, but that doesn't mean impossible.
  - iliis 13y ago
    Yes, absolutely correct. Which is why I said for some definition of possible. 'Feasible' probably would have been the better choice. Keep in mind that we're talking exponential here! e^x blows up really really fast. Yes, it's not impossible to break 4092bit RSA but it is impossible for all practical purposes [AFAIK]. While it is technically possible to run Crysis on a Commodore it is useless when you have to wait a year to render a single frame.
  - powrtoch 13y ago

MrBra 13y ago

I read the article but all I got is that somehow the reasearchers brought quantum theory principles into game theory. I don't think that's enough explaining, even for a layman...

jonahx 13y ago

Sounds interesting but the article was vague. If anyone understands it, could you provide a real world example and explain how their discoveries would apply. They mentioned auctions but didn't give any details.

domdip 13y ago

My interpretation of this for those with a bit of game theory background: Locality (in physics) can be translated (in game theory) as a constraint on correlated equilibria, by pretty basic observations about Bayesian probability. Generally in game theory when you lift constraints on correlated equilibria you (weakly) expand the possible Nash equilibria. So one of their points seems to be that the quantum context (non-locality) allows for more (potentially better) equilibria. They don't emphasize applications of this, but one of them could be that distributed quantum systems could have better outcomes than distributed systems in the classical setting. (One way to analyze distributed systems is by viewing components as independent actors in a game.) There is also an identification between payoff functions and Bell inequalities, but I am not sure how profound this is really. It feels more like a technical point. Payoff functions are not terribly fundamental in game theory (compared to equilibria, for instance).

anigbrowl 13y ago

(from http://arxiv.org/pdf/1210.1173v1.pdf http://arxiv.org/pdf/1210.1173v1.pdf) However, in certain cases the players may adapt their strategy depending on a piece of advice. The latter is delivered to all players by an advisor. This opens the possibility for the players to adopt correlated strategies, which can outperform independent strategies. There are various forms that advice can take. For example in the case of correlated classical advice, the advice is represented by a classical variable, l, with prior r(l). Each player can then choose a strategy depending on his type and on l. ... For Bayesian games, the possibility of having access to nonlocal correlations, for instance using entanglement, has important implications. First let us imagine that the players can share quantum advice, that is, the advisor is able to produce entangled particles and to send them to the players, who then perform local measurements on their particles. Since the statistics of such measurements can in general not be reproduced by any classical local model, the players now have access to strategies which would be impossible in the case of a classical advisor. Thus, players sharing quantum advice can outperform any classical players. So, if some players have information that other players don't, they can outperform the others? Astonishing :-|

domdip 13y ago
It's not about some players performing better than others. It's about the game maybe having a better outcome (for everyone) in one case than the other. Maybe it's not surprising that 'extra' information improves the game. But a point of this article (IMO) was to formally show that you could link the notion of 'extra' in physics to 'better' in game theory. I'm not arguing that this is profound, but it's not completely trivial either.
- smegel 13y ago
  Doesn't "link" imply some common cause or connection? Saying you can use A to improve B isn't really what I would describe as a link. Why couldn't it have been titled "quantum non-locality could change game theory equilibrium"...or would it have not been sensational enough?
  - 13y ago

d23 13y ago

Since this is being upvoted on hacker news, I'm assuming this is more than the typical BS filled science journalism. But I wish there were a site that allowed individuals respected in a similar field to have a disproportionate weight when upvoting articles like this. Or perhaps they could give a summary of the context surrounding the article. It'd be nice to get a sense of the magnitude of these discoveries. Given that this is coming directly from a university, I don't doubt that it is important. I'd just like to know how important.

jostmey 13y ago

Just because the mathematical operations are similar does not mean the two fields are at all related. The quadratic equation has many uses, but that does not mean that everything the equation is used for is in some way fundamentally related.

jostmey 13y ago
UPDATE: To quote the authors: "In the present paper, we discuss such a link, ALBEIT a much more MODEST one, between Bell nonlocality and the theory of Bayesian games—also referred to as games with incomplete information."