https://doi.org/10.1140/epjb/e2016-70600-x
Regular Article
Dissipative dynamics of a quantum two-state system in presence of nonequilibrium quantum noise
Institut für Theoretische Physik, Universität
Hamburg, Jungiusstraße
9, 20355
Hamburg,
Germany
a e-mail: niklas.mann@physik.uni-hamburg.de
Received:
10
October
2016
Received in final form:
3
November
2016
Published online:
21
December
2016
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 in the limit of zero transport voltage. A straightforward extension to the case with a time-periodic ac voltage is shown.
Key words: Mesoscopic and Nanoscale Systems
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2016