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Work and efficiency fluctuations in a quantum Otto cycle with idle levels
Maron F Anka1, Thiago R de Oliveira1, Daniel Jonathan1
1Instituto de Física <a href="https://ror.org/02rjhbb08">Universidade Federal Fluminense</a> - Av. Gal. Milton Tavares de Souza s/n, 24210-346 Niterói, Rio de Janeiro, Brazil.
Physical Review. E
|July 18, 2024
Summary
This study on a quantum Otto heat engine reveals that while interspin coupling affects work fluctuations, they remain large. The microscopic engine is thus unreliable for work extraction.
Area of Science:
- Quantum thermodynamics
- Statistical mechanics
- Condensed matter physics
Background:
- Quantum heat engines offer insights into fundamental thermodynamic principles at microscopic scales.
- Understanding work and efficiency fluctuations is crucial for assessing the reliability of quantum engines.
Purpose of the Study:
- To investigate the performance of a two-spin quantum Otto heat engine, focusing on work and efficiency fluctuations.
- To establish relationships between engine performance and equilibrium properties like magnetization and magnetic susceptibility.
Main Methods:
- Analysis of a two-spin quantum Otto heat engine model with Heisenberg interaction.
- Calculation of mean values and fluctuations of work and efficiency.
- Correlation of engine performance with equilibrium magnetic properties.
Main Results:
- Output work and fluctuations directly correlate with system magnetization and magnetic susceptibility.
- Interspin coupling's effect on fluctuations depends on other parameters due to "idle" energy levels.
- Regions for lower relative fluctuations were identified, but remained high.
Conclusions:
- The two-spin quantum Otto engine exhibits large relative fluctuations in work and efficiency.
- This inherent unreliability limits its practical application as a consistent work source.
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