Atom sistemlerinde kalıcı dolaşıklık

Robust Entanglement in Atomic SystemsüuşOzgü r Cakıremail:ocakir@gmail.comBilkent University, Physics Department ANKARASeptember 2005AbstractVarious models for generation of robust atomic entangled states and their imple-mentation with current accessible technologies are proposed and worked out. De-terministic creation of long living Bell states with respect to metastable states inthree-level Λ type systems is studied. Strong atom-field coupling drives atoms into atransient entangled state followed by an irreversible evolution towards a long-livingmaximally entangled state featuring robustness against dipole-allowed transitions.First, generation of pairwise atomic entanglement in cavities in ideal case is dis-cussed, extension to multi-party entangled states is made. Observation of photonsemitted from the system signals the generation of a Bell state.The interaction of multi-level atoms with body-assisted electro-magnetic fieldin the presence of dispersing and absorbing media is studied and these results areapplied to the description of a pair of Λ type atoms passing by a microsphere.Microspheres give rise to resonances of well defined height and width with easyaccess to strong and weak coupling regimes for atom-field interaction, thus enablingrealization of the proposed scheme of ?robust entanglement of three-level atoms?.Even in realistic settings it is possible to obtain quite high amount of entanglementat spatially well separated distances.Then we focus on steady state entanglement between atomic dipoles. It is shownthat two dipoles in free space driven by a classical driving field become entangled inthe steady state. The crucial point is that, this entanglement is irrespective of theinitial state and may be preserved as long as the engineered system is kept intact.1Absorption effects in real cavities are studied, and an input-output relation isformulated in the presence of a source in the cavity. Extraction of non-classicalphoton states from a cavity is investigated.Keywords: Quantum Optics, Quantum Information Theory, EPR paradox, Entan-glement, Cavity Quantum Electrodynamics, Quantum Open Systems, Decoherence,Quantum Noise2