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arXiv · 1610.03062

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

Niklas Mann·Jochen Brüggemann·Michael Thorwart
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Abstract

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

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Niklas Mann, Jochen Brüggemann, Michael Thorwart. 2016-10-10. Dissipative dynamics of a quantum two-state system in presence of nonequilibrium quantum noise. https://doi.org/10.1140/epjb/e2016-70600-x

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