ENTANGLEMENT AND PSEUDOMIXTURES 1

Maciej Kuna

Published Jan 1, 1998• 0 citations

Abstract

In a recent paper Sanpera et al. have shown [1], that for the simplest binary composite systems any density matrix can be described in terms of only product vectors. The purpose of this note is to show that posibillity of decomposing any state as pseudomixtures does not depend on dimension of the subsystems. In a composite quantum system one can find states that involve different degrees of correlation between subsystems. From the physical point of view the most important characterization of such states is related to the nature of these correlations. Separable states involve correlations which can be explained by classical models [2]. The notion of inseparability or entanglement is related to specific relations existing only in pure quantum systems. Recently a general characterization of separable states was given in the language of vectors from natural cone of the Tomita-Takesaki theory, and quantum origin of this notion was explained [3]. Quantum character of entaglement plays a crucial role in quantum communication [4], cryptography [5], and quantum computation [6]. A state of a composite quantum system is inseparable if it cannot by represented as a convex mixture of tensor products

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