The quasi-degenerative Raman model and entanglement reciprocation / O modelo Raman quase-degenerado e transferencia de emaranhamento

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The main purpose of this dissertation is to study a new model to describe the interaction between an atom and a mode of the quantized electromagnetic field and also its application to the entanglement reciprocation problem between qubits and continuous variable systems. Firstly, we review the main model used to describe the atom field interaction,known as the Jaynes Cummings model, and also make an introduction to entanglement, aiming to establish the measures that will be used latter.After this introductory part and based on the known degenerate Raman model, we propose the Quasi degenerate Raman model with the intention to describe the interaction between a three level atom in the L configuration and a mode of the quantized field. We admit that the field, in the dispersive limit, couples the two lower atomic levels to the highest energy state, which is then eliminated by a unitary transformation, or by an adiabatic elimination.In this way, it plays the role of a virtual level which enables the effective transition between the other two lower energy levels. To get to the final form of the effective Hamiltonian we still assume that the energy difference between these two lower energy levels is too small when compared to the detuning of the excited level. From the equations that describe the dynamics of an atom interacting with a coherent field, we investigate the entanglement transfer from two maximally entangled atoms to two cavities initially prepared in a pure separable coherent state. Naturally, we also consider the transfer on the opposite way, field -- atom. Our results show that the complete entanglement reciprocation is possible. The last subject of this dissertation is the cluster type entangled coherent states. We propose a new scheme for the generation of this kind of state among four spatially separated cavities using only one atom and two Ramsey zones and also study the energy dissipation influence

ASSUNTO(S)

atom-photon interaction interação atomo-foton manipulação de emaranhamento entanglement manipulation

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