Finding decompositions of a class of separable states

2012/02/16 by Alfsen, Erik, Shultz, Fred
#46N50 #81P16 #81P40 #FOS: Mathematics #FOS: Physical sciences #Operator Algebras (math.OA) #Primary 15A30 #Quantum Physics (quant-ph) #Secondary 46L30

paper · doi:10.48550/arxiv.1202.3673

Abstract

By definition a separable state has the form ∑ A_i ⊗ B_i, where 0 ≤ A_i, B_i for each i. In this paper we consider the class of states which admit such a decomposition with B₁, ..., B_p having independent images. We give a simple intrinsic characterization of this class of states, and starting with a density matrix in this class, describe a procedure to find such a decomposition with B₁, ..., B_p having independent images, and A₁, ..., A_p being distinct with unit trace. Such a decomposition is unique, and we relate this to the facial structure of the set of separable states. A special subclass of such separable states are those for which the rank of the matrix matches one marginal rank. Such states have arisen in previous studies of separability (e.g., they are known to be a class for which the PPT condition is equivalent to separability). The states investigated also include a class that corresponds (under the Choi-Jamiołkowski isomorphism) to the quantum channels called quantum-classical and classical-quantum by Holevo.

Related

• Channel-state duality and the separability problem
• A cone approach to the quantum separability problem
• Canonical Form and Separability of PPT States on Multiple Quantum Spaces
• Decomposition of completely symmetric states states
• Smallest disentangling state spaces for general entangled bipartite quantum states