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Work Fluctuations in Ergotropic Heat Engines.

Giovanni Chesi1, Chiara Macchiavello1,2, Massimiliano Federico Sacchi2,3

  • 1National Institute for Nuclear Physics, Sezione di Pavia, Via Agostino Bassi 6, 27100 Pavia, Italy.

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Summary
This summary is machine-generated.

This study explores work fluctuations in quantum Otto engines, analyzing optimal unitary operations for extracting ergotropy. Researchers found that a specific non-Hermitian operation violates thermodynamic uncertainty relations.

Keywords:
ergotropyquantum heat enginesquantum thermodynamicsthermodynamic uncertainty relationstwo-stroke Otto cycles

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Area of Science:

  • Quantum Thermodynamics
  • Statistical Mechanics
  • Quantum Information

Background:

  • Ergotropic heat engines utilize quantum systems to perform work.
  • Quantum Otto engines are a key model for studying thermodynamic cycles.
  • Ergotropy represents the maximum work extractable via unitary evolution.

Purpose of the Study:

  • Investigate work fluctuations in two-stroke quantum Otto engines.
  • Analyze ergotropy extraction from quantum systems at different temperatures.
  • Examine the role of unitary strokes in work statistics.

Main Methods:

  • Derivation of complete work statistics for two qutrits.
  • Analysis of optimal unitary strokes (U1, U2, U3).
  • Study of thermodynamic uncertainty relations (TURs) and fluctuation theorems.

Main Results:

  • Identified three optimal unitary strokes: swap (U1), idle swap (U2), and their composition (U3).
  • U1 and U2 are Hermitian, while U3 is non-Hermitian.
  • The non-Hermitian transformation U3 violates thermodynamic uncertainty relations derived from detailed fluctuation theorems.

Conclusions:

  • The nature of unitary strokes significantly impacts work fluctuations and thermodynamic relations.
  • Non-Hermitian operations can lead to violations of established thermodynamic uncertainty bounds.
  • Findings offer insights into the fundamental limits of work extraction in quantum engines.