Proteção de estados coerentes em pontos quânticos acoplados

AUTOR(ES)
DATA DE PUBLICAÇÃO

2011

RESUMO

The theoretical and experimental developments that took place in quantum computing and quantum information in recent decades make the realization of a quantum computer more and more feasible. However, the necessary control over the dynamics of quantum states of the system, used to implement this computer, is strongly limited by decoherence generated by the interaction of this system with the environment. Decoherence can be avoided, among other ways, through the existence of a decoherence-free subspace. Further- more, it is possible to make the eect of decoherence take the system to a desired state, by applying the reservoir engineering technique. This work presents the conditions for the existence of a decoherence-free subspace and the condition for a state to be protected from decoherence in the context of the reservoir engineering technique. Considering a system consisting of two quantum dots coupled by tunneling under the action of a laser field, it is shown the protection of an indirect exciton state, belonging to a decoherence-free sub- space of dimension 2. The protected state can be described by the parameters of the laser, therefore, the generation of any state that can be represented on the surface of the Bloch sphere can be achieved through the manipulation of amplitude and phase of the laser field. Implementation of the Deutsch algorithm is proposed, taking advantage of the fact that the protection of the state corresponds to the partial realization of this algorithm, requiring only the execution of the measure for its completion.

ASSUNTO(S)

descoerência proteção de estados computação quântica fisica computadores quânticos decoherence state protection quantum computation

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