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Spectral Conditions on the State of a Composite Quantum System Implying its Separability

G. A. Raggio
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Abstract

For any unitarily invariant convex function F on the states of a composite quantum system which isolates the trace there is a critical constant C such that F(w)<= C for a state w implies that w is not entangled; and for any possible D > C there are entangled states v with F(v)=D. Upper- and lower bounds on C are given. The critical values of some F's for qubit/qubit and qubit/qutrit bipartite systems are computed. Simple conditions on the spectrum of a state guaranteeing separability are obtained. It is shown that the thermal equilbrium states specified by any Hamiltonian of an arbitrary compositum are separable if the temperature is high enough.

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G. A. Raggio. 2005-05-11. Spectral Conditions on the State of a Composite Quantum System Implying its Separability. https://doi.org/10.1088/0305-4470/39/3/013

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