Séminaire de groupe
Longdistance entanglement between two defects embedded in a linear chain of ions 
Endre Kajari 
Theoetische Physik, Universite de Sarrebruck (Allemagne) 
lundi 05 mars 2012 , 10h25 
Salle de séminaire du groupe de Physique Statistique 
Decoherence is generally considered as major obstacle for the observation of quantum effects in the macroscopic world, and its description within the framework of open quantum systems, has attracted a lot of attention. However, there exist scenarios in which the coupling of a small system to a quantum reservoir supports the occurrence of quantum effects. Along these lines, it has been recently shown that it is possible to create longdistance entanglement between two remote oscillators that couple indirectly via a harmonic chain [1]. In this simple model, the finite chain plays the role of a common reservoir that drives the two oscillators into a (quasi) steady state. <br> <br> In my talk, I shall discuss two slightly different mechanisms [2] that give rise to steadystate entanglement. I shall show how to quantify the steadystate entanglement by means of the logarithmic negativity and present its dependence on the initial states of the oscillators and the reservoir, as well as on the parameters of the underlying microscopic model. Finally, I want to highlight an experimentally feasible setup to test the existence of longdistance entanglement: an ion chain in a linear Paul trap with two embedded impurities, whose transverse modes resemble the two degrees of freedom that become entangled. <br> <br> [1] A. Wolf, G. de Chiara, E. Kajari, E. Lutz and G. Morigi, EPL 95, 60008 (2011). <br> [2] E. Kajari, A. Wolf, E. Lutz and G. Morigi, arXiv:1112.5300v1 (2011). 
