Non-Signaling Parallel Repetition Using de Finetti Reductions

作者：Arnon Friedman Rotem^*; Renner Renato^*; Vidick Thomas^*

来源：IEEE Transactions on Information Theory, 2016, 62(3): 1440-1457.

DOI：10.1109/TIT.2016.2516022

• Parallel repetition
• threshold theorem
• multiplayer games
• non-signalling players
• de Finetti theorems
• non-locality
• correlations
• probability theory
• quantum entanglement

In the context of multiplayer games, the parallel repetition problem can be phrased as follows: given a game G with optimal winning probability 1 - alpha and its repeated version Gn (in which n games are played together, in parallel), can the players use strategies that are substantially better than ones in which each game is played independently? This question is relevant in physics for the study of correlations and plays an important role in computer science in the context of complexity and cryptography. In this paper, the case of multiplayer non-signaling games is considered, i.e., the only restriction on the players is that they are not allowed to communicate during the game. For complete-support games (games where all possible combinations of questions have non-zero probability to be asked) with any number of players, we prove a threshold theorem stating that the probability that non-signaling players win more than a fraction 1-alpha+beta of the n games is exponentially small in n beta(2) for every 0 <= beta <= alpha. For games with incomplete support, we derive a similar statement for a slightly modified form of repetition. The result is proved using a new technique based on a recent de Finetti theorem, which allows us to avoid central technical difficulties that arise in standard proofs of parallel repetition theorems.

• 出版日期2016-3