Catalytic Entropy Principles

TL;DR

This paper introduces a unified principle for quantum entropy measures that aligns with the second thermodynamics law, providing operational insights and applications in quantum thermodynamics and information processing.

Contribution

It presents the first unified principle for general quantum entropies consistent with thermodynamics laws, applicable to both standard and nonextensive quantum thermostatistics.

Findings

Operational characterization of general quantum entropies.

Maximization of cross entropy reveals new thermodynamic features.

Applications to quantum state transitions and cooling processes.

Abstract

The entropy shows an unavoidable tendency of disorder in thermostatistics according to the second thermodynamics law. This provides a minimization entropy principle for quantum thermostatistics with the von Neumann entropy and nonextensive quantum thermostatistics with special Tsallis entropy. Our goal in this work is to provide operational characterizations of general entropy measures. We present the first unified principle consistent with the second thermodynamics law in terms of general quantum entropies for both quantum thermostatistics and nonextensive quantum thermostatistics. This further reveals new features beyond the second thermodynamics law by maximization the cross entropy during irreversible measurement procedures. The present result is useful for asymptotical tasks of quantum entropy estimations and universal quantum source encoding without the state tomography. It is further applied to single-shot state transitions and cooling in quantum thermodynamics with limited information. These results should be interesting in the many-body theory and long-range quantum information processing.