Dresden 2009 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 26: Poster II

DY 26.36: Poster

Donnerstag, 26. März 2009, 16:00–18:00, P1A

Dynamically stabilized entanglement via cyclic processes — •Thomas Jahnke and Günter Mahler — Universität Stuttgart, 1. Institut für Theoretische Physik, Pfaffenwaldring 57, 70550 Stuttgart

It is well known that the contact of a quantum system to a thermal bath has a negative effect on the entanglement within the system: Beyond a certain temperature, no static entanglement can survive at all.

Here we investigate the entanglement between two coupled spins driven through two-step-cycles. In the first step, spin (1) is driven by a time dependent Hamiltonian. In the second step, spin (2) is coupled to a "Schrödinger bath" (i.e. a finite quantum embedding) [1]. Both steps are thus described by pure Schrödinger dynamics. We find that after a few cycles the system approaches a stable limit cycle independent of its initial state. This periodic attractor provides entanglement between the spins even at bath temperatures for which no thermal entanglement could exist (cf. [2]).

[1] J. Gemmer, M. Michel and G. Mahler: Quantum Thermodynamics, Springer 2004

[2] J. Cai, S. Popescu, H. J. Briegel, arXiv:0809.4906