2016/10/10 by Niklas Mann, Jochen Brüggemann, Michael Thorwart
Chemistry · Physics and Astronomy · #Advanced Physical and Chemical Molecular Interactions #Advanced Thermodynamics and Statistical Mechanics #Correlation function (quantum field theory) #Dephasing #Dissipative system #Non-equilibrium thermodynamics #Quantum #Quantum and electron transport phenomena #Quantum dynamics #Quantum system #Quantum tunnelling #Relaxation (psychology) #cond-mat.mes-hall
paper · pdf · doi:10.1140/epjb/e2016-70600-x
published as Eur. Phys. J. B 89 (2016), 279
arxiv created 2016/10/10 · openalex created_date 2016/10/21 · openalex publication_date 2016/12/01 · arxiv updated 2016/12/20 · openalex updated_date 2026/08/05
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.