Production of entanglement with highly-mixed states

TL;DR

This paper demonstrates that entanglement can be generated between highly mixed states through direct unitary interactions, challenging the notion that subsystem purity is necessary for entanglement creation.

Contribution

It shows that entanglement can be produced without high purity, contrasting previous beliefs about the importance of subsystem purity.

Findings

Entanglement can be generated between states with near-zero purity.

Purity of subsystems is not essential for entanglement creation.

Contrasts with prior studies emphasizing subsystem purity.

Abstract

We study production of entanglement with highly-mixed states. We find that entanglement between highly mixed states can be generated via a direct unitary interaction even when both states have purities arbitrarily close to zero. This indicates that purity of a subsystem is not required for entanglement generation. Our result is in contrast to previous studies where the importance of the subsystem purity was emphasized.