Quantum Coherence and Holevo Bound

TL;DR

This paper links quantum coherence loss to information loss in measurements and shows quantum discord equals the minimal difference in local coherence, providing new insights into quantum correlations.

Contribution

It establishes the equivalence between coherence loss and information loss, and demonstrates that quantum discord equals the minimal difference in local coherence for bipartite systems.

Findings

Quantum coherence loss is equivalent to information loss after measurement.

Quantum discord equals the minimal difference in local coherence.

Provides a new perspective on quantum correlations and coherence.

Abstract

We establish the equivalence between the loss of coherence due to mixing in a quantum system and the loss of information after performing a projective measurement. Subsequently, it is demonstrated that the quantum discord, a measure of correlation for the bipartite system $\rho_{Alice\leftarrow Bob}$, is identical to the minimum difference (over all projectors {|i><i|}) between local coherence (LQICC monotone) on Bob side and coherence of the reduced density matrix $\rho^B$.