Dissipative dynamics of a quantum two-state system in presence of nonequilibrium quantum noise

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• 作者：Niklas Mann ; Jochen Brüggemann ; Michael Thorwart
• 关键词：Mesoscopic and Nanoscale Systems
• 刊名：The European Physical Journal B
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：89
• 期：12
• 全文大小：
• 刊物类别：Physics and Astronomy
• 刊物主题：Condensed Matter Physics; Physics, general; Complex Systems; Fluid- and Aerodynamics; Solid State Physics;
• 出版者：Springer Berlin Heidelberg
• ISSN：1434-6036
• 卷排序：89

文摘

We analyze the real-time dynamics of a quantum two-state system in the presence ofnonequilibrium quantum fluctuations. The latter are generated by a coupling of thetwo-state system to a single electronic level of a quantum dot which carries anonequilibrium tunneling current. We restrict to the sequential tunneling regime andcalculate the dynamics of the two-state system, of the dot population, and of thenonequilibrium charge current on the basis of a diagrammatic perturbative method valid fora weak tunneling coupling. We find a nontrivial dependence of the relaxation and dephasingrates of the two-state system due to the nonequilibrium fluctuations which is directlylinked to the structure of the unperturbed central system. In addition, aHeisenberg-Langevin-equation of motion allows us to calculate the correlation function ofthe nonequilibrium fluctuations. By this, we obtain a generalized nonequilibriumfluctuation relation which includes the equilibrium fluctuation-dissipation theorem in thelimit of zero transport voltage. A straightforward extension to the case with atime-periodic ac voltage is shown.