Strong Coupling Thermodynamics of Open Quantum Systems

Area of Science:

• Quantum thermodynamics
• Statistical mechanics
• Open quantum systems

Background:

• Understanding thermodynamics in quantum systems is crucial for quantum technologies.
• Existing frameworks often assume weak system-reservoir coupling or Markovian dynamics.
• Strong coupling and non-Markovian effects are prevalent in realistic quantum scenarios.

Purpose of the Study:

• To develop a general thermodynamic framework for open quantum systems.
• To extend the first and second laws of thermodynamics to arbitrary coupling strengths and initial conditions.
• To identify a thermodynamic signature for non-Markovian dynamics.

Main Methods:

• Formulation of a general thermodynamic framework for open quantum systems.
• Derivation of the first and second laws applicable to strong system-reservoir coupling.
• Adaptation of thermodynamic properties for strong coupling regimes.
• Investigation of initial system-reservoir conditions (factorized and correlated).

Main Results:

• The first and second laws of thermodynamics are derived for arbitrary system-reservoir coupling strengths and initial conditions.
• Thermodynamic properties are generalized to strong coupling, bridging equilibrium and weak-coupling limits.
• Thermodynamic quantities can be extracted solely from system observables.
• A negative entropy production rate is identified as a signature of non-Markovianity.

Conclusions:

• A unified thermodynamic framework is established for open quantum systems, valid beyond the weak-coupling and Markovian approximations.
• The framework allows for the calculation of thermodynamic properties from measurable system observables.
• Negative entropy production serves as a direct indicator of non-Markovian dynamics in quantum systems.