Research Interests

I am a physicist who has specialized in the fundamental physics of information processing, questions such as "Is there a technology-independent limit to the energy efficiency of computers, like the limit thermodynamics imposes on the efficiency of steam engines?" Somewhat surprisingly, the answer is No: computers in principle can be arbitrarily efficient converters of physical energy into mathematical work. More recently I have participated in extending classical information and computation theory to encompass a subtler kind of information, carried by systems such as single atoms or photons. This information obeys quantum laws, e.g. it exhibits interference, and cannot be copied. Quantum information-processing effects, some of which have been demonstrated experimentally, include eavesdrop-detecting cryptographic systems, "quantum teleportation," in which an unknown quantum state is disembodied from one particle and recreated in another, and, in principle, dramatically faster ways of solving certain mathematical problems such as factoring large numbers. Besides the physics of computation, I have long been interested in a converse problem -- using the tools of information and computation theory to arrive at suitably mathematical, non-anthropocentric measures of a physical system's "complexity," of that which increases when a self-organizing system organizes itself.

Membership Type


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Primary Section

Section 34: Computer and Information Sciences

Secondary Section

Section 33: Applied Physical Sciences