1999/08/13 by Seth Lloyd · 11 voices · 1,138 citations
Computer Science · Physics and Astronomy · #Algorithm #Body weight #Classical mechanics #Computability, Logic, AI Algorithms #Computation #Computer science #Constant (computer programming) #Degrees of freedom (physics and chemistry) #Gravitation #Gravitational constant #Kilogram #Laptop #Physical constant #Physics #Process (computing) #Quantum #Quantum Computing Algorithms and Architecture #Quantum Mechanics and Applications #Quantum computer #Quantum mechanics #Volume (thermodynamics) #quant-ph
paper · pdf · doi:10.1038/35023282
published in Nature 406(6799), 1047-1054 (Nature Portfolio) · 22 pages, plain TeX, submitted to Nature, replaced to incorporate additional content and references
arxiv created 2000/02/14 · openalex publication_date 2000/08/01 · arxiv updated 2015/06/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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 ℏ 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.