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Main Authors: Rupush, William, Grånäs, Oscar
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2403.02022
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author Rupush, William
Grånäs, Oscar
author_facet Rupush, William
Grånäs, Oscar
contents We present a new proposal for distinguishing heat from work based on a control-theoretic observability decomposition. We derive a Hermitian operator representing instantaneous dissipation of observable energy, and suggest a generalization of the von-Neumann entropy which can account for the model-uncertainty also present in pure states if the measured observables are informationally incomplete. In this view, the transition from a fundamental to a thermodynamic model consists in mapping the fundamental density matrix to an effective one, generally of lower dimension, encoding only what is observable given the constraints of our sensor and actuator capabilities. The generalized entropy captures the information loss incurred in this mapping. The theory is illustrated for the central spin model, where we show that the application of external controls can increase the size of thermal fluctuations and lower the entropy.
format Preprint
id arxiv_https___arxiv_org_abs_2403_02022
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Heat and Work in Quantum Thermodynamics: a Cybernetic Approach
Rupush, William
Grånäs, Oscar
Quantum Physics
37N20
We present a new proposal for distinguishing heat from work based on a control-theoretic observability decomposition. We derive a Hermitian operator representing instantaneous dissipation of observable energy, and suggest a generalization of the von-Neumann entropy which can account for the model-uncertainty also present in pure states if the measured observables are informationally incomplete. In this view, the transition from a fundamental to a thermodynamic model consists in mapping the fundamental density matrix to an effective one, generally of lower dimension, encoding only what is observable given the constraints of our sensor and actuator capabilities. The generalized entropy captures the information loss incurred in this mapping. The theory is illustrated for the central spin model, where we show that the application of external controls can increase the size of thermal fluctuations and lower the entropy.
title Heat and Work in Quantum Thermodynamics: a Cybernetic Approach
topic Quantum Physics
37N20
url https://arxiv.org/abs/2403.02022