Dresden 2011 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 50: Quantum Effects: Entanglement and Decoherence
Q 50.2: Talk
Thursday, March 17, 2011, 10:45–11:00, SCH A01
Long-distance entanglement between two harmonic ocillators via a quantum reservoir — •Endre Kajari1,2, Alexander Wolf2, Gabriele De Chiara3,5, Eric Lutz4, and Giovanna Morigi1,5 — 1Theoretische Physik, Universität des Saarlandes, D-66041 Saarberücken, Germany — 2Institut für Quantenphysik, Universität Ulm, D-89069 Ulm, Germany — 3Grup de Física Teorica, Departament de Física, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain — 4Department of Physics, University of Augsburg, D-86135 Augsburg, Germany — 5Grup d’Òptica, Departament de Física, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain
We discuss the creation of entanglement between two harmonic oscillators
that interact via a common reservoir consisting of a chain of
harmonic oscillators with nearest-neighbor coupling. The oscillators
are initially prepared in squeezed states with squeezing parameter r,
whereas the chain starts from a thermal state at temperature T. The entanglement between
the oscillators is studied as a function of r and T using the logarithmic negativity. We first identify a parameter regime in which the chain acts as an Ohmic environment and recover a long time behavior of the entanglement that is qualitatively in agreement with the predictions of [1].
When the oscillators couple to two separate
sites of the chain, decoherence free subspaces support
quasi-stationary quantum correlations between the oscillators for
certain frequency ranges. The requirements for long-distance entanglement are identified and
possible experimental realizations are envisaged.
J. P. Paz, A. J. Roncaglia, Phys. Rev. Lett. 100, 220401 (2008).