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DY: Fachverband Dynamik und Statistische Physik

DY 16: Quantum Dynamics, Decoherence and Quantum Information

DY 16.1: Vortrag

Dienstag, 2. April 2019, 10:00–10:15, H6

The dynamics of the Lindblad equation when including feedback from the environment — •Bernd Michael Fernengel and Barbara Drossel — Hochschulstraße 6, 64289 Darmstadt

The Lindblad equation describes the time evolution of an open quantum system when the environment relaxes fast. In addition to the von-Neumann term * describing the unitary time evolution according to the Schroedinger equation * the Lindblad equation takes into account stochastic transitions between different states. It assumes that the environment is not changed as the state of the system changes.

We abandon this last assumption and allow for an (instantaneous) feedback of the (mixed) state of the ensemble onto itself via the environment. One way to realize this would be to have several systems coupled to the same environment. This leads to a time evolution equation that is nonlinear in the density matrix. By using the example of a two-level system, we show explicitly that various types of instabilities and bifurcations can occur.