caa a22 4500 467892571 CHVBK 20180406152753.0 cr unu---uuuuu 170328e20060201xx s 000 0 eng 10.1007/s10955-005-8015-9 doi (NATIONALLICENCE)springer-10.1007/s10955-005-8015-9 Janzing Dominik Institut für Algorithmen und Kognitive Systeme, Arbeitsgruppe Quantum Computing, Universität Karlsruhe, Am Fasanengarten 5, 76131, Karlsruhe, Germany aut On the Computational Power of Molecular Heat Engines [Elektronische Daten] [Dominik Janzing] A heat engine is a machine which uses the temperature difference between a hot and a cold reservoir to extract work. Here both reservoirs are quantum systems and a heat engine is described by a unitary transformation which decreases the average energy of the bipartite system. On the molecular scale, the ability of implementing a (good) unitary heat engine is closely connected to the ability of performing logical operations and classical computing. This is shown by several examples: (1)The most elementary heat engine is a SWAP-gate acting on 1 hot and 1 cold two-level systems with different energy gaps. (2)An optimal unitary heat engine on a pair of 3-level systems can directly implement OR and NOT gates, as well as copy operations. The ability to implement this heat engine on each pair of 3-level systems taken from the hot and the cold ensemble therefore allows universal classical computation. (3)Optimal heat engines operating on one hot and one cold oscillator mode with different frequencies are able to calculate polynomials and roots approximately. (4)An optimal heat engine acting on 1 hot and n cold 2-level systems with different level spacings can even solve the NP-complete problem KNAPSACK. Whereas it is already known that the determination of ground states of interacting many-particle systems is NP-hard, the optimal heat engine is a thermodynamic problem which is NP-hard even for n non-interacting spin systems. This result suggests that there may be complexity-theoretic limitations on the efficiency of molecular heat engines. Springer Science + Business Media, Inc., 2006 Second law nationallicence complexity theory nationallicence molecular computing nationallicence nanoscopic machines nationallicence Journal of Statistical Physics Kluwer Academic Publishers-Plenum Publishers 122/3(2006-02-01), 531-556 0022-4715 122:3<531 2006 122 10955 https://doi.org/10.1007/s10955-005-8015-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10955-005-8015-9 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Janzing Dominik Institut für Algorithmen und Kognitive Systeme, Arbeitsgruppe Quantum Computing, Universität Karlsruhe, Am Fasanengarten 5, 76131, Karlsruhe, Germany aut NATIONALLICENCE 773 0- Journal of Statistical Physics Kluwer Academic Publishers-Plenum Publishers 122/3(2006-02-01), 531-556 0022-4715 122:3<531 2006 122 10955 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer