Information and entropy in quantum Brownian motion: Thermodynamic entropy versus von Neumann entropy

TL;DR

This paper compares thermodynamic and von Neumann entropies in quantum Brownian motion, revealing deviations at low temperatures due to entanglement, impacting interpretations of information capacity and thermodynamics.

Contribution

It provides a detailed comparison between thermodynamic and von Neumann entropies in quantum Brownian motion, highlighting the significance of entanglement at low temperatures.

Findings

Deviations between the two entropies occur at low temperatures.

Entanglement causes differences between thermodynamic and von Neumann entropy.

Implications for the Landauer principle and information theory in quantum systems.

Abstract

We compare the thermodynamic entropy of a quantum Brownian oscillator derived from the partition function of the subsystem with the von Neumann entropy of its reduced density matrix. At low temperatures we find deviations between these two entropies which are due to the fact that the Brownian particle and its environment are entangled. We give an explanation for these findings and point out that these deviations become important in cases where statements about the information capacity of the subsystem are associated with thermodynamic properties, as it is the case for the Landauer principle.