UEber-Computers from Exotic Physics?

摘要

Although quantum computers seem unlikely to solve NP-complete problems quickly, certain other extraordinary, speculative physical processes would allow construction of computers with that ability and much more. Time travel, for instance, would make it possible to efficiently solve any PSPACE problem, includinq those harder than NP-complete ones-such as how to play the perfect game of chess on any size board, including those larger than the standard 8 × 8 version.”