Physics of Computation

Information processing by computers has become one of the hallmarks of our age. Because computation, no matter how abstract, is fundamentally a physical process, it is inevitably governed by the laws of physics, and these relationships have been studied by physicists and computer scientists in a number of contexts over the past twenty years or more.

Principal concern has focused on energy consumption in the computational process, and on questions of reversible and irreversible computation. In particular, the question of minimal energy requirements has produced a lively debate that continues at present. The following references summarize the developments over the past two decades, and contain references to all the original papers.

92.``Physics and Computation," T. Toffoli, Int. J. Theor. Phys. 21, 165-175 (1982). (I)

93.``Conservative Logic," E. Fredkin and T. Toffoli, Int. J. Theor. Phys. 21, 219-253 (1982). (I)

94.``The Thermodynamics of Computation - a Review," C.H. Bennett, Int. J. Theor. Phys. 21, 905-940 (1982). (I)

95.``Information is Physical," R. Landauer, Phys. Today 44, 23-29, May (1991). (I)

96.``Minimal Energy Requirements in Communication," R. Landauer, Science, 272, 1914-1918 (1996). (A)

The following articles take issue with the arguments above by Bennett and Landauer. Each article is followed by rejoinders from these authors and others.

97.``Dissipation in Computation," W. Porod, R.O Grondin, D.K. Ferry, and G. Porod, Phys. Rev. Lett. 52, 232-235 (1984). (A)

98.``The Computer and the Heat Engine," O. Costa de Beauregard, Found. Phys. 19, 725-727 (1989). (A)

99.``Letter to the Editor," E. Biedermann, Phys. Today 43 (11), 122 (1990). (A)