Local purity distillation with bounded classical communication

TL;DR

This paper extends the theory of local purity distillation in bipartite quantum systems to scenarios with limited classical communication, providing computable formulas and practical examples for classical-quantum states.

Contribution

It introduces a bounded communication framework for local purity distillation and derives an efficiently computable expression for classical-quantum states.

Findings

Derived a formula for purity distillation with bounded communication.

Provided examples illustrating the tradeoff curves.

Extended previous unbounded channel results to bounded scenarios.

Abstract

Local pure states are an important resource for quantum computing. The problem of distilling local pure states from mixed ones can be cast in an information theoretic paradigm. The bipartite version of this problem where local purity must be distilled from an arbitrary quantum state shared between two parties, Alice and Bob, is closely related to the problem of separating quantum and classical correlations in the state and in particular, to a measure of classical correlations called the one-way distillable common randomness. In Phys. Rev. A 71, 062303 (2005), the optimal rate of local purity distillation is derived when many copies of a bipartite quantum state are shared between Alice and Bob, and the parties are allowed unlimited use of a unidirectional dephasing channel. In the present paper, we extend this result to the setting in which the use of the channel is bounded. We demonstrate that in the case of a classical-quantum system, the expression for the local purity distilled is efficiently computable and provide examples with their tradeoff curves.