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Operational approach to quantum stochastic thermodynamics.

Philipp Strasberg1

  • 1Physics and Materials Science Research Unit, University of Luxembourg, 1511 Luxembourg, Luxembourg and Física Teòrica: Informació i Fenòmens Quàntics, Departament de Física, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain.

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This study introduces a quantum stochastic thermodynamics framework using experimental controls. It defines key thermodynamic quantities at the trajectory level, validating fundamental laws and enabling analysis of quantum feedback experiments.

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Area of Science:

  • Quantum Physics
  • Thermodynamics
  • Statistical Mechanics

Background:

  • Traditional thermodynamics relies on macroscopic ensembles, limiting its application to microscopic quantum systems.
  • Quantum systems exhibit unique behaviors, necessitating a thermodynamic framework that accounts for quantum effects and experimental control.
  • Previous quantum thermodynamics frameworks often lacked a trajectory-level description or direct connection to experimental interventions.

Purpose of the Study:

  • To establish a quantum stochastic thermodynamics framework based on experimentally controllable interventions.
  • To define and analyze thermodynamic quantities (energy, heat, work, entropy) at the quantum trajectory level.
  • To bridge the gap between trajectory-based and ensemble-level descriptions in quantum thermodynamics.

Main Methods:

  • Development of a theoretical framework utilizing standard system-bath dynamics assumptions.
  • Incorporation of insights from the repeated interaction framework for quantum systems.
  • Definition of thermodynamic quantities at the individual quantum trajectory level.

Main Results:

  • Established the validity of the first law of thermodynamics at the trajectory level.
  • Proved the validity of the second law of thermodynamics on average for quantum trajectories.
  • Successfully applied the framework to analyze the thermodynamic efficiency of quantum feedback control experiments for photon number state stabilization.

Conclusions:

  • The developed framework provides a robust foundation for quantum stochastic thermodynamics, directly linked to experimental control.
  • The theory naturally handles incomplete information and interpolates between trajectory and ensemble descriptions.
  • This approach opens new avenues for rigorously investigating quantum effects in thermodynamics and analyzing quantum feedback protocols.