Thermodynamics of the Coarse-Graining Master Equation.

Area of Science:

• Quantum thermodynamics
• Statistical mechanics
• Open quantum systems

Background:

• Coarse-graining is crucial for modeling open quantum systems.
• The secular approximation is often used but can limit accuracy.
• Establishing a consistent thermodynamic framework for quantum systems is an ongoing challenge.

Purpose of the Study:

• To derive a generator for open quantum system evolution over finite time intervals using coarse-graining.
• To investigate the applicability of the Lindblad-Gorini-Kossakowski-Sudarshan generator without secular approximation.
• To demonstrate a consistent thermodynamic framework, including the second law, for these systems.

Main Methods:

• Applying a coarse-graining approach to derive the system's generator.
• Utilizing full counting statistics in conjunction with the derived formalism.
• Including switching work for reservoir coupling and decoupling.

Main Results:

• A generator for finite-time evolution of open quantum systems is derived.
• The approach generally yields a Lindblad-Gorini-Kossakowski-Sudarshan generator without requiring secular approximation.
• A consistent thermodynamic framework is demonstrated, aligning with the second law when heat currents are reservoir-defined.

Conclusions:

• The coarse-graining method provides a robust way to study open quantum systems.
• The derived framework offers a new perspective on thermodynamics in quantum systems.
• Pedagogical examples illustrate the practical application and validity of the findings.