David Elieser Deutsch (born 18 May 1953) is a British physicist at the University of Oxford. He is a visiting professor in the Department of Atomic and Laser Physics at the Centre for Quantum Computation (CQC) in the Clarendon Laboratory of the University of Oxford. He pioneered the field of quantum computation by formulating a description for a quantum Turing machine, as well as specifying an algorithm designed to run on a quantum computer. He has also proposed the use of entangled states and Bell's theorem for quantum key distribution and is a proponent of the many-worlds interpretation of quantum mechanics.

His work on quantum algorithms began with a 1985 paper, later expanded in 1992 along with Richard Jozsa to produce the Deutsch–Jozsa algorithm, one of the first examples of a quantum algorithm that is exponentially faster than any possible deterministic classical algorithm. In his 1985 paper, he also suggests the use of entangled states and Bell's theorem for quantum key distribution. In his nomination for election as a Fellow of the Royal Society (FRS) in 2008, his contributions were described as [having] laid the foundations of the quantum theory of computation, and has subsequently made or participated in many of the most important advances in the field, including the discovery of the first quantum algorithms, the theory of quantum logic gates and quantum computational networks, the first quantum error-correction scheme, and several fundamental quantum universality results. He has set the agenda for worldwide research efforts in this new, interdisciplinary field, made progress in understanding its philosophical implications (via a variant of the many-universes interpretation) and made it comprehensible to the general public, notably in his book The Fabric of Reality.

Since 2012, he has been working on constructor theory, an attempt at generalizing the quantum theory of computation to cover not just computation but all physical processes. Together with Chiara Marletto, he published a paper in December 2014 entitled Constructor theory of information, that conjectures that information can be expressed solely in terms of which transformations of physical systems are possible and which are impossible.

David Deutsch