Catalytic Decoupling of Quantum Information

TL;DR

This paper introduces catalytic decoupling, a new approach in quantum information theory that uses an uncorrelated ancilla to achieve decoupling, unifying several quantum tasks and providing a resource theory framework.

Contribution

It presents the concept of catalytic decoupling, extending standard decoupling by incorporating an uncorrelated ancilla, and offers a tight characterization using max-mutual information.

Findings

Unifies tasks like correlation erasure and quantum state merging.

Provides a resource theory of decoupling.

Characterizes catalytic decoupling with max-mutual information.

Abstract

The decoupling technique is a fundamental tool in quantum information theory with applications ranging from quantum thermodynamics to quantum many body physics to the study of black hole radiation. In this work we introduce the notion of catalytic decoupling, that is, decoupling in the presence of an uncorrelated ancilla system. This removes a restriction on the standard notion of decoupling, which becomes important for structureless resources, and yields a tight characterization in terms of the max-mutual information. Catalytic decoupling naturally unifies various tasks like the erasure of correlations and quantum state merging, and leads to a resource theory of decoupling.