Modified Landauer's principle: How much can the Maxwell's demon gain by using general system-environment quantum state?

TL;DR

This paper generalizes Landauer's principle to scenarios where the system and environment are initially correlated and the environment is athermal, revealing correction terms that can reduce the work needed for information erasure.

Contribution

It introduces a modified Landauer's principle accounting for initial correlations and athermal environments, expanding the principle's applicability in quantum thermodynamics.

Findings

Modified Landauer's bound includes correction terms for correlated and athermal environments.

Correction terms can lower the work required for memory erasure.

The principle applies to non-completely positive maps and finite-time processes.

Abstract

The Landauer principle states that decrease in entropy of a system, inevitably leads to a dissipation of heat to the environment. This statement is usually established by considering the system to be in contact with an environment that is initially in a thermal state, with the system-environment initial state being in a product state. Here we show that a modified Landauer principle, with correction terms, still holds even if the system and environment are initially correlated and the environment is in an athermal state. This is the most general quantum mechanically allowed operation in the Maxwell demon's arsenal, and, in particular, includes non-completely positive but physically realizable maps on the system. The correction terms provide an advantage: they reduce the work required by the Maxwell's demon to erase its memory. The modified principle also incorporates the possibility of arbitrary charge flows, including the usual heat flow, between system and environment. Furthermore, we consider a case where the system is in contact with a large initially-decoupled athermal environment, and we derive the finite-time modified Landauer's bound for the same.