The Fundamental Physical Limits of Computation

Editor’s note (6/1/2011): We are making the text of this July 1985 article freely available for 30 days to coincide with the publication of a paper on entropy and quantum systems by Vlatko Vedral. He authored our June 2011 cover story and blogs about his latest work , which discusses the research featured in this 1985 article. A computation, whether it is performed by electronic machinery, on an abacus or in a biological system such as the brain, is a physical process

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The Fundamental Physical Limits of Computation