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DOI http://dx.doi.org/10.1103/PhysRevE.55.1355
Title Dissipative quantum systems with a potential barrier. III. Steady state nonequilibrium flux and reaction rate
Creator/Author Ankerhold, J. ; Grabert, H. [Fakultaet fuer Physik der Albert-Ludwigs-Universitaet, Hermann-Herder-Strasse 3, D-79104 Freiburg (Germany)]
Publication Date1997 Feb 01
OSTI IdentifierOSTI ID: 467328
Other Number(s)Journal ID: PLEEE8; ISSN 1063-651X; TRN: TRN: 9704M0232
Resource TypeJournal Article
Resource RelationJournal Name: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics; Journal Volume: 55; Journal Issue: 2; Other Information: PBD: Feb 1997
Subject66 PHYSICS; METASTABLE STATES; DYNAMICS; QUANTUM MECHANICS; TUNNEL EFFECT; DENSITY MATRIX; SEMICLASSICAL APPROXIMATION; TEMPERATURE DEPENDENCE; ENERGY LOSSES; FLUCTUATIONS; CRITICAL TEMPERATURE
Description/AbstractWe study the real time dynamics of a dissipative quantum system in a metastable state which may decay by crossing a potential barrier. Starting from an initial state where the system is in thermal equilibrium on one side of the barrier, the time evolution of the density matrix is evaluated analytically in the semiclassical approximation for coordinates near the barrier top. In a region about a critical temperature T{sub c} large quantum fluctuations render the harmonic approximation of the potential insufficient and anharmonicities become essential. Accounting for non-Gaussian fluctuation modes, we show that the density matrix approaches a quasistationary state with a constant flux across the barrier. This extends our earlier results [Phys. Rev. E {bold 51}, 4267 (1995)] on the quantum generalization of the Kramers flux state to the region about T{sub c}. By matching the flux state onto the equilibrium state on one side of the barrier, we determine the decay rate out of the metastable state. The rate constant shows a changeover from thermally activated decay to quantum tunneling for temperatures below T{sub c}. {copyright} {ital 1997} {ital The American Physical Society}
Country of PublicationUnited States
LanguageEnglish
FormatMedium: X; Size: pp. 1355-1374
System Entry Date2008 Feb 04

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