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Related Experiment Video

Updated: Apr 15, 2026

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

Published on: May 30, 2014

Quantum thermodynamics of general quantum processes.

Felix Binder¹, Sai Vinjanampathy², Kavan Modi³

¹Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom.

Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics

|April 15, 2015

Summary

This study introduces an operational framework for quantum thermodynamics, defining work and heat for open quantum systems. It establishes a first law of thermodynamics consistent with the second law, linking heat and entropy changes to state majorization.

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Area of Science:

Quantum thermodynamics
Statistical mechanics
Quantum information theory

Background:

Defining work and heat in quantum systems is challenging, especially for arbitrary quantum states.
Extending classical thermodynamics to individual quantum systems requires new theoretical frameworks.

Purpose of the Study:

To formulate an operational thermodynamics for open quantum systems undergoing general quantum processes.
To derive an operational first law of thermodynamics and demonstrate its consistency with the second law.

Main Methods:

Utilizing completely positive and trace-preserving (CPTP) maps to model quantum processes.
Developing an operational approach to define work and heat extraction.
Analyzing the relationship between state majorization and thermodynamic quantities.

Main Results:

An operational first law of thermodynamics was derived for general quantum processes.
Heat is positive when the input state majorizes the output state.
Entropy change is also positive under the same majorization condition, linking the first and second laws.

Conclusions:

The derived operational framework provides a consistent approach to quantum thermodynamics.
Majorization of quantum states is a key condition connecting heat, entropy, and thermodynamic laws.
This work strengthens the connection between operational definitions and fundamental thermodynamic principles in quantum systems.