Physical Cost of Erasing Quantum Correlation

TL;DR

This paper establishes that erasing quantum correlations incurs a fundamental entropy cost, linking quantum information erasure to physical energy costs and extending Landauer's principle to quantum correlations.

Contribution

It introduces a universal bound relating quantum correlation erasure to entropy change, demonstrating the physical nature of quantum correlations.

Findings

Quantum correlation erasure is bounded by entropy change.

Erasing quantum correlation respects Landauer's principle.

The bound applies to various quantum processes like thermalization.

Abstract

Erasure of information stored in a quantum state requires energy cost and is inherently an irreversible operation. If quantumness of a system is physical, does erasure of quantum correlation as measured by discord also need some energy cost? Here, we show that change in quantum correlation is never larger than the total entropy change of the system and the environment. The entropy cost of erasing correlation has to be at least equal to the amount of quantum correlation erased. Hence, quantum correlation can be regarded as genuinely physical. We show that the new bound leads to the Landauer erasure. The physical cost of erasing quantum correlation is well respected in the case of bleaching of quantum information, thermalization, and can have potential application for any channel leading to erasure of quantum correlation.