John WatrousResearch interests

Present-day computers are classical computing devices: each component of a classical computer has a definite logical state before and after each step of a computation, and computations proceed according to rules dictated by sequences of deterministic (or sometimes randomized) logical operations. According to the theory of quantum information, however, which offers an abstraction of the information-theoretic aspects of quantum mechanical systems, classical computations represent only a limited subset of the computations that can potentially be implemented by physical devices. Professor Watrous's research on the theory of quantum information and computation studies the powers and limitations of this computational paradigm.

The main objective of Professor Watrous's research is to better understand the nature of the computations that can potentially be implemented by quantum computers, as well as interactions among multiple quantum computers in cooperative and competitive settings. He is also interested in fundamental aspects of quantum information, and in the development of mathematical techniques that are useful for reasoning about quantum information and computation.

Degrees and awards

BS (SUNY, Stony Brook), MS, PhD (Wisconsin-Madison)

Cheriton Fellow (2009-2012); Fellow of the Canadian Institute for Advanced Research (2008); Canada Research Chair II (2002-2006)

Representative publications

R. Jain, Z. Ji, S. Upadhyay, and J. Watrous. QIP = PSPACE. Journal of the ACM 58(6): article 30, 2011.

J. Watrous. Zero-knowledge against quantum attacks. SIAM Journal on Computing 39(1): 25–58, 2009.

J. Watrous. Semidefinite programs for completely bounded norms. Theory of Computing 5: article 11, 2009.

G. Gutoski and J. Watrous. Toward a general theory of quantum games. Proceedings of the 39th ACM Symposium on Theory of Computing, pages 565-574, 2007.

University of Waterloo
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