- A-212 (STCS Seminar Room)
We prove that the complexity class QIP, which consists of all problems having quantum interactive proof systems, is contained in PSPACE. This containment is proved by applying a parallelized form of the matrix multiplicative weights update method to a class of semidefinite programs that captures the computational power of quantum interactive proofs. As the containment of PSPACE in QIP follows immediately from the well-known equality IP = PSPACE, the equality QIP = PSPACE follows (joint work with Zhengfeng Ji, Sarvagya Upadhyay and John Watrous).
Winner of the Best Paper Award STOC 2010.