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OSA Workshop on Entanglement and Quantum Decoherence

Entanglement Evolution Between Two Isolated Multiqubit Systems

Stanley Chan, Z. Ficek, M. D. Reid

Published Jan 1, 2008• 0 citations
Publisher

Abstract

We examine the time evolution of entanglement between two qubits of a system of four qubits. The system is composed of two separate cavities each containing a single two-level atom. The qubits of the system are the two atoms and the two cavity modes. We show that during the transfer of an initial entanglement from atoms to the cavity modes, an additional entanglement is induced between the atoms and the cavity modes. Thus, during the evolution, the system effectively behaves as a six qubit system. In addition, we study the entanglement evolution for an imperfect matching of the atoms to the cavity modes. We show that the imperfect matching can force a stable entangled state to evolve in time and may produce a continuous entanglement in time.

DOI
10.1364/weqd.2008.embs1

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We examine the time evolution of entanglement between two qubits of a system of four qubits. The system is composed of two separate cavities each containing a single two-level atom. The qubits of the system are the two atoms and the two cavity modes. We show that during the transfer of an initial entanglement from atoms to the cavity modes, an additional entanglement is induced between the atoms and the cavity modes. Thus, during the evolution, the system effectively behaves as a six qubit system. In addition, we study the entanglement evolution for an imperfect matching of the atoms to the cavity modes. We show that the imperfect matching can force a stable entangled state to evolve in time and may produce a continuous entanglement in time.
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We show that two qubits can be entangled by local interactions with an entangled two-mode continuous variable state. This is illustrated by the evolution of two two-level atoms interacting with a two-mode squeezed state. Two modes of the squeezed field are injected respectively into two spatially separate cavities and the atoms are then sent into the cavities to interact resonantly with the cavity field. We find that the atoms may be entangled even by a two-mode squeezed state which has been decohered while penetrating into the cavity.