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Measurement-based quantum Otto engine with a two-spin system coupled by anisotropic interaction: Enhanced efficiency
Chayan Purkait1, Asoka Biswas1
1Department of Physics, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India.
Physical Review. E
|June 17, 2023
Summary
This study explores a quantum Otto engine (QOE) using two coupled spins. Finite-time operations reveal oscillatory efficiency, offering potential for improved performance over quasistatic engines.
Area of Science:
- Quantum thermodynamics
- Quantum information science
- Condensed matter physics
Background:
- Quantum Otto engines (QOE) are theoretical devices utilizing quantum effects for thermodynamic cycles.
- Understanding the impact of finite-time operations and interactions is crucial for practical quantum engine design.
Purpose of the Study:
- To investigate the performance and efficiency of a measurement-based quantum Otto engine.
- To analyze the effects of finite-time unitary operations and Heisenberg anisotropic interactions on engine performance.
- To explore the potential for enhanced work output and efficiency through precise timing of quantum processes.
Main Methods:
- Modeling a two-spin system coupled by Heisenberg anisotropic interaction as the working substance.
- Utilizing nonselective quantum measurement to drive the engine cycle.
- Calculating thermodynamic quantities based on transition probabilities between energy eigenstates and measurement basis states.
- Analyzing engine performance across different timescales for unitary operations (finite time τ).
Main Results:
- Engine efficiency peaks in the τ→0 limit and approaches the adiabatic value as τ→∞.
- Finite-time operations and anisotropic interactions lead to oscillatory behavior in efficiency.
- Oscillations are attributed to interference effects in transition amplitudes during unitary stages.
- In the short-time regime, optimized timing can yield higher work output and reduced heat absorption compared to quasistatic engines.
- The effect of an always-on heat bath is negligible at very short timescales.
Conclusions:
- Finite-time quantum operations introduce unique dynamics, enabling performance beyond quasistatic limits.
- Quantum interference offers a mechanism to enhance the efficiency of quantum engines.
- Careful control over the timing of unitary processes is key to optimizing quantum engine performance.
- Measurement-based quantum engines with anisotropic interactions show promising avenues for efficient energy conversion.
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