John Harrison Watrous is the Technical Director of IBM Quantum Education at

IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

and was a professor of

computer science Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, ...

at the David R. Cheriton School of Computer Science at the

University of Waterloo The University of Waterloo (UWaterloo, UW, or Waterloo) is a Public university, public research university located in Waterloo, Ontario, Canada. The main campus is on of land adjacent to uptown Waterloo and Waterloo Park. The university also op ...

, a member of the Institute for Quantum Computing, an affiliate member of the

Perimeter Institute for Theoretical Physics Perimeter Institute for Theoretical Physics (PI, Perimeter, PITP) is an independent research centre in foundational theoretical physics located in Waterloo, Ontario, Canada. It was founded in 1999. The institute's founding and major benefactor i ...

and a Fellow of the Canadian Institute for Advanced Research.John Watrous
at the Canadian Institute for Advanced Research website. He was a faculty member in the Department of Computer Science at the

University of Calgary {{Infobox university , name = University of Calgary , image = University of Calgary coat of arms without motto scroll.svg , image_size = 150px , caption = Coat of arms , former ...

from 2002 to 2006 where he held a

Canada Research Chair Canada Research Chair (CRC) is a title given to certain Canadian university research professors by the Canada Research Chairs Program. Program goals The Canada Research Chair program was established in 2000 as a part of the Government of Canada ...

quantum computing A quantum computer is a computer that exploits quantum mechanical phenomena. On small scales, physical matter exhibits properties of wave-particle duality, both particles and waves, and quantum computing takes advantage of this behavior using s ...

. He is an editor of the journal ''

Theory of Computing ''Theory of Computing'' is a peer-reviewed open access scientific journal covering theoretical computer science. The journal was established in 2005 and is published by the Department of Computer Science of the University of Chicago. The editor-i ...

'' and former editor for the journal '' Quantum Information & Computation''. His research interests include

quantum information Quantum information is the information of the state of a quantum system. It is the basic entity of study in quantum information theory, and can be manipulated using quantum information processing techniques. Quantum information refers to both t ...

and

quantum computation A quantum computer is a computer that exploits quantum mechanical phenomena. On small scales, physical matter exhibits properties of both particles and waves, and quantum computing takes advantage of this behavior using specialized hardware. C ...

. He is well known for his work on quantum interactive proofs, and the quantum analogue of the celebrated result IP =

PSPACE In computational complexity theory, PSPACE is the set of all decision problems that can be solved by a Turing machine using a polynomial amount of space. Formal definition If we denote by SPACE(''f''(''n'')), the set of all problems that can ...

: QIP = PSPACE. This was preceded by a series of results, showing QIP can be constrained to 3 messages, QIP is contained in

EXP Exp or EXP may stand for: * Exponential function, in mathematics * Expiry date of organic compounds like food or medicines * Experience point An experience point (often abbreviated as exp or XP) is a unit of measurement used in some tabletop r ...

, and the 2-message version of QIP is in PSPACE. He has also published important papers on

quantum finite automata In physics, a quantum (: quanta) is the minimum amount of any physical entity (physical property) involved in an interaction. The fundamental notion that a property can be "quantized" is referred to as "the hypothesis of quantization". This me ...

and quantum cellular automata. With

Scott Aaronson Scott Joel Aaronson (born May 21, 1981) is an American Theoretical computer science, theoretical computer scientist and Schlumberger Centennial Chair of Computer Science at the University of Texas at Austin. His primary areas of research are ...

, he showed that certain forms of

time travel Time travel is the hypothetical activity of traveling into the past or future. Time travel is a concept in philosophy and fiction, particularly science fiction. In fiction, time travel is typically achieved through the use of a device known a ...

can make quantum and classical computation equivalent: together, the authors showed that quantum effects do not offer advantages for computation if computers can send information to the past through a type of

closed timelike curve In mathematical physics, a closed timelike curve (CTC) is a world line in a Lorentzian manifold, of a material particle in spacetime, that is "closed", returning to its starting point. This possibility was first discovered by Willem Jacob van St ...

proposed by the physicist

David Deutsch David Elieser Deutsch ( ; ; born 18 May 1953) is a British physicist at the University of Oxford, often described as the "father of quantum computing". He is a visiting professor in the Department of Atomic and Laser Physics at the Centre for ...

. He obtained his Ph.D. in 1998 at the

University of Wisconsin–Madison The University of Wisconsin–Madison (University of Wisconsin, Wisconsin, UW, UW–Madison, or simply Madison) is a public land-grant research university in Madison, Wisconsin, United States. It was founded in 1848 when Wisconsin achieved st ...

under the supervision of Eric Bach..John Watrous
at the Institute for Quantum Computing directory.

References

{{DEFAULTSORT:Watrous, John Living people Academic staff of the University of Waterloo University of Wisconsin–Madison alumni Theoretical computer scientists Cellular automatists Canada Research Chairs Year of birth missing (living people) Quantum information scientists