Coherence and measurement in quantum thermodynamics.

Area of Science:

• Thermodynamics
• Quantum Mechanics
• Information Theory

Background:

• Thermodynamics is a macroscopic theory applicable to devices like engines and solar cells.
• Quantum mechanics introduces quantum effects in finite-size systems, posing challenges for classical thermodynamics.
• Recent advances in quantum thermodynamics include quantum thermal engines and fluctuation theorems.

Purpose of the Study:

• To identify genuinely quantum aspects of quantum thermodynamics.
• To investigate the thermodynamic work costs associated with quantum information processing tasks.
• To explore the role of quantum coherences in thermodynamic work.

Main Methods:

• Identifying information processing tasks unique to quantum mechanics (projections).
• Analyzing the thermodynamic work required for realizing these quantum projections.
• Comparing quantum projections with classical information erasure (Landauer's principle).

Main Results:

• Quantum projections require thermodynamic work only for quantum states exhibiting coherences.
• This contrasts with information erasure, which has a thermodynamic cost for both classical and quantum states.
• The findings impact quantum work fluctuation relations and single-shot thermodynamics.

Conclusions:

• Quantum coherences are essential for specific quantum information processing tasks with thermodynamic work costs.
• This work distinguishes quantum thermodynamics from classical thermodynamics by highlighting unique quantum phenomena.
• The research advances the understanding of thermodynamics at the nanoscale and in quantum regimes.