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arXiv · 0704.1965

Quantum entanglement of decohered two-mode squeezed states in absorbing and amplifying environment

Phoenix S. Y. Poon·C. K. Law
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Abstract

We investigate the properties of quantum entanglement of two-mode squeezed states interacting with linear baths with general gain and loss parameters. By explicitly solving for ρfrom the master equation, we determine analytical expressions of eigenvalues and eigenvectors of ρ^{T_A} (the partial transposition of density matrix ρ). In Fock space, ρ^{T_A} is shown to maintain a block diagonal structure as the system evolves. In addition, we discover that the decoherence induced by the baths would break the degeneracy of ρ^{T_A}, and leads to a novel set of eigenvectors for the construction of entanglement witness operators. Such eigenvectors are shown to be time-independent, which is a signature of robust entanglement of two-mode squeezed states in the presence of noise.

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Phoenix S. Y. Poon, C. K. Law. 2007-04-16. Quantum entanglement of decohered two-mode squeezed states in absorbing and amplifying environment. https://doi.org/10.1103/physreva.76.012333

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