Dresden 2011 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 44: Poster Session Correlated Electrons

TT 44.3: Poster

Thursday, March 17, 2011, 10:00–13:00, P1

Coupled Spins in a Dissipative Environment — •Etienne Gärtner, Andrew Mitchell, and Ralf Bulla — Institute of Theoretical Physics, University of Cologne, Zülpicherstr. 77 50937 Cologne, Germany

One of the fascinating consequences of quantum mechanics is that different coupled subsystems can become entangled. A classic example is a quantum impurity coupled to a dissipative environment (the standard spin-boson model). Here we consider the natural extension of this scenario, studying the entanglement generated between two impurities which are coupled to a common bosonic bath. This two-spin-boson model is analysed in detail using the bosonic numerical renormalization group (NRG) technique, with the Von Neumann entropies and phase diagram extracted directly. Recently the question has been posed as to whether a common bath could also generate entanglement between spatially separated spins. To address the question of the lenghtscale for such entanglement, we couple the spins to 1 or 2 dimensional bosonic host lattices, and calculate the dependence of physical properties on impurity separation. To this end, we extend the bosonic NRG to deal with the two-bath effective model that results.