Frankfurt 2006 – scientific programme
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Q: Quantenoptik und Photonik
Q 15: Quanteninformation II
Q 15.1: Talk
Monday, March 13, 2006, 17:00–17:15, HI
Equilibrium entanglement in open, noisy quantum systems — •Lorenz Hartmann1, Wolfgang Dür1,2, and Hans-Jürgen Briegel1,2 — 1Institut für Theoretische Physik, Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Österreich — 2Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Innsbruck, Österreich
We show that quantum mechanical entanglement can prevail even in noisy open quantum systems at finite temperatures, and despite the deteriorating effect of decoherence. The system consists of a number N of interacting quantum particles and it can exchange energy and particles with some environment. The effect of decoherence is counteracted by a simple mechanism, where system particles are randomly reset to some standard initial state, e.g. by replacing them with particles form the environment. We present a master equation that describes this process, which we can solve analytically for small N. If we vary the interaction strength and the reset against decoherence rate, we find a threshold below which the equilibrium state is classically correlated, and above which there is a parameter region with genuine entanglement.