Quantum-correlating power of local quantum channels

TL;DR

This paper introduces the concept of quantum-correlating power (QCP) of local quantum channels, providing analytical results and exploring properties like super-activation, to understand how quantum correlations can be generated locally.

Contribution

It defines QCP, proves the optimal input states are classical-classical, and derives explicit QCP expressions for specific single-qubit channels, advancing understanding of local quantum correlation creation.

Findings

Optimal input states for maximum QCP are classical-classical.

Analytic QCP expression derived for amplitude damping channels.

Super-activation of QCP demonstrated for phase damping channels.

Abstract

Quantum correlation can be created by local operations from a classically correlated state. We define quantum-correlating power (QCP) of a local quantum channel as the maximum amount of quantum correlation that can be created by the channel. The quantum correlation that we discuss in this article is defined on the left part of the bipartite state. We prove that for any local channel, the optimal input state, which corresponds to the maximum quantum correlation in the output state, must be a classical-classical state. Further, the single-qubit channels with maximum QCP can be found in the class of rank-1 channels which take their optimal input states to rank-2 quantum-classical states. The analytic expression for QCP of single-qubit amplitude damping channel is obtained. Super-activation property of QCP, i.e., two zero-QCP channels can consist a positive-QCP channel, is discussed for single-qubit phase damping channels.