Optimal State Merging Without Decoupling

TL;DR

This paper presents an optimal state merging protocol that leverages direct amplitude and phase correlation establishment, bypassing traditional decoupling methods, and highlights the fundamental importance of these correlations in quantum information tasks.

Contribution

It introduces a novel optimal state merging protocol based on direct correlation measures, challenging conventional decoupling-based approaches.

Findings

Protocol achieves optimality in state merging

Correlations suffice for quantum information processing

Strengthens link between error correction and state merging

Abstract

We construct an optimal state merging protocol by adapting a recently-discovered optimal entanglement distillation protcol [Renes and Boileau, Phys. Rev. A . 73, 032335 (2008)]. The proof of optimality relies only on directly establishing sufficient "amplitude" and "phase" correlations between Alice and Bob and not on usual techniques of decoupling Alice from the environment. This strengthens the intuition from quantum error-correction that these two correlations are all that really matter in two-party quantum information processing.