Ultimate physical limits to computation
Abstract
Computers are physical systems: what they can and cannot do is dictated by the laws of physics. In particular, the speed with which a physical device can process information is limited by its energy and the amount of information that it can process is limited by the number of degrees of freedom it possesses. This paper explores the physical limits of computation as determined by the speed of light c, the quantum scale hbar and the gravitational constant G. As an example, quantitative bounds are put to the computational power of an `ultimate laptop' with a mass of one kilogram confined to a volume of one liter.
 Publication:

Nature
 Pub Date:
 August 2000
 DOI:
 10.1038/35023282
 arXiv:
 arXiv:quantph/9908043
 Bibcode:
 2000Natur.406.1047L
 Keywords:

 Quantum Physics;
 Quantum Physics
 EPrint:
 22 pages, plain TeX, submitted to Nature, replaced to incorporate additional content and references