Freiburg 2019 – scientific programme
Sessions | Days | Selection | Search | Updates | Downloads | Help
FM: Fall Meeting
FM 13: Open and Complex Quantum Systems I
FM 13.3: Talk
Monday, September 23, 2019, 14:45–15:00, 3042
Quantum information and open-system dynamics: Complete positivity, divisibility and time-dependent transport — •Maarten Wegewijs1,2, Viktor Reimer2, Konstantin Nestmann2, and Mikhail Pletyukhov2 — 1Peter Grünberg Institute, Forschungszentrum Jülich, Germany — 2Institute for Theory of Statistical Physics, RWTH Aachen University, Germany
Time-evolution in quantum information theory hinges on complete-positivity (CP) which is equivalent to the Kraus form of the dynamical map and closely tied to entanglement.
To exploit this in the study of the dynamics of open systems – beyond the framework of Lindblad equations – it is advantageous to strike a bridge to methods of statistical physics based on quantum master equations.
In this talk, I will explain how this can be done on a very general level using standard real-time techniques, expressing Kraus operators in Keldysh diagrams. I will illustrate how the Kraus operators provide new insights into the dynamics, in particular, into the dynamics of the environment as it is affected by the system. Even for a system as simple as a resonant level this provides some surprising insights and allows the continuous fermionic bath into which the fermion decays to be effectively reduced to just two fermions. I furthermore show that different notions of Markovianity (semigroup- and CP-divisibility) correspond to clearly measurable features in the time-dependent transport current.
V. Reimer, M. Wegewijs, et al, arXiv: 1903.04195
V. Reimer, M. Wegewijs, K. Nestmann, M. Pletyukhov, arXiv:1808.09395.