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Negativity as a distance from a separable state

M. Khasin·R. Kosloff·D. Steinitz
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Abstract

The computable measure of the mixed-state entanglement, the negativity, is shown to admit a clear geometrical interpretation, when applied to Schmidt-correlated (SC) states: the negativity of a SC state equals a distance of the state from a pertinent separable state. As a consequence, a SC state is separable if and only if its negativity vanishes. Another remarkable consequence is that the negativity of a SC can be estimated "at a glance" on the density matrix. These results are generalized to mixtures of SC states, which emerge in certain quantum-dynamical settings.

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M. Khasin, R. Kosloff, D. Steinitz. 2007-01-01. Negativity as a distance from a separable state. https://doi.org/10.1103/physreva.75.052325

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