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Specific heat anomalies of open quantum systems
Gert-Ludwig Ingold1, Peter Hänggi, Peter Talkner
1Institut für Physik, Universität Augsburg, D-86135 Augsburg, Germany. gert.ingold@physik.uni-augsburg.de
Summary
The specific heat of open quantum systems can be negative, but this represents a difference between system and bath specific heats, ensuring thermodynamic stability. Anomalous temperature dependence is observed in damped quantum harmonic oscillators.
Area of Science:
- Quantum thermodynamics
- Statistical mechanics
- Condensed matter physics
Background:
- Evaluating specific heat in open quantum systems presents challenges.
- The thermodynamic partition function is a key tool for analysis.
- Previous studies showed potential for negative specific heat in free damped particles.
Purpose of the Study:
- To investigate the specific heat of open damped quantum systems, particularly the quantum harmonic oscillator.
- To clarify the interpretation of negative specific heat values in open systems.
- To explore anomalous temperature dependencies in specific heat.
Main Methods:
- Utilizing the thermodynamic partition function as a ratio of system-plus-bath to bath partition functions.
- Analyzing stylized minimal models with single-oscillator heat baths.
- Calculating the difference in specific heats between the coupled bath and the bath alone.
Main Results:
- The specific heat difference can be negative, but individual specific heats remain positive, satisfying stability criteria.
- A dip in the specific heat difference as a function of temperature is observed for damped quantum harmonic oscillators.
- Anomalous temperature dependence of specific heat values is elucidated through minimal models.
Conclusions:
- The interpretation of specific heat in open quantum systems requires careful consideration of the bath contribution.
- Thermodynamic stability is maintained despite potentially negative specific heat differences.
- The study provides insights into the behavior of specific heat in quantum systems and its relation to the density of states.
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