Physics and Computation

Abstract : Physics imposes fundamental constraints on the ultimate potentialities of computing mechanisms. The most prominent fundamental constraint coming from physics that is felt today is the finiteness of the speed of light. This constraint implies that communication paths inside of a computer should be as short as possible. For maximum speed, we would also like to have massive parallelism. This motivates us to consider the computational capabilities of cellular automata: uniform arrays of identical processors, each communicating only with nearby neighboring processors. Keywords: Computer architecture; Physics; Computation; Information; Modeling; Cellular automata; Reversibility; Quantum mechanics; Time.