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arXiv · 0811.4527

Representation of entanglement by negative quasi-probabilities

J. Sperling·W. Vogel
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Abstract

Any bipartite quantum state has quasi-probability representations in terms of separable states. For entangled states these quasi-probabilities necessarily exhibit negativities. Based on the general structure of composite quantum states, one may reconstruct such quasi-propabilities from experimental data. Because of ambiguity, the quasi-probabilities obtained by the bare reconstruction are insufficient to identify entanglement. An optimization procedure is introduced to derive quasi-probabilities with a minimal amount of negativity. Negativities of optimized quasi-probabilities unambiguously prove entanglement, their positivity proves separability.

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J. Sperling, W. Vogel. 2008-11-27. Representation of entanglement by negative quasi-probabilities. https://doi.org/10.1103/physreva.79.042337

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