arXiv:2409.12759 · Physical Review A

Informational nonequilibrium concentration

Chung-Yun Hsieh, Benjamin Stratton, Hao‐Cheng Weng, Valerio Scarani

Published May 13, 2025• 3 citations

Abstract

Informational contributions to thermodynamics can be studied in isolation by considering systems with fully degenerate Hamiltonians. In this regime, being in nonequilibrium (termed ) provides thermodynamic resources, such as extractable work, from the information content. The usefulness of informational nonequilibrium creates an incentive to obtain more of it, motivating the question of how to : can we increase the local informational nonequilibrium of a product state ρ ⊗ ρ under a global closed system (unitary) evolution? We fully solve this problem analytically, showing that it is for two-qubits, and it is always possible to find states achieving this in higher dimensions. Specifically for two-qutrits, we find that there is a single unitary achieving optimal concentration for state, for which we uncover a . We further discuss the notion of in this framework, initial global correlations' ability to concentration, and applications to concentrating purity and intrinsic randomness.

DOI: 10.1103/physreva.111.052423

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