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Experimental Realization of a Quantum Refrigerator Driven by Indefinite Causal Orders
Xinfang Nie1,2, Xuanran Zhu1, Keyi Huang1
1Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China.
Physical Review Letters
|September 16, 2022
Summary
Quantum technologies utilize indefinite causal order (ICO) for novel thermodynamic effects. Researchers experimentally demonstrated ICO refrigeration, enhancing performance over 3x with a density matrix exponentiation approach.
Area of Science:
- Quantum Physics
- Quantum Thermodynamics
- Quantum Information
Background:
- Indefinite causal order (ICO) is crucial for emerging quantum technologies.
- Quantum thermodynamics explores heat, work, and energy in quantum systems.
Purpose of the Study:
- To experimentally investigate quantum thermodynamics driven by indefinite causal order.
- To demonstrate and enhance the performance of an indefinite causal order refrigerator.
Main Methods:
- Utilized nuclear magnetic resonance (NMR) system to realize ICO of thermalizing channels.
- Constructed a single cycle of an ICO refrigerator based on Maxwell's demon.
- Employed density matrix exponentiation (DME) approach to improve the coefficient of performance (COP).
Main Results:
- Demonstrated cooling and heating of a working substance via ICO, even with reservoirs at the same temperature.
- Evaluated ICO refrigerator performance, noting bounded COP due to projection probabilities.
- Achieved over a 3-fold enhancement in COP using the DME approach.
Conclusions:
- Experimental validation of nonclassical heat exchange through ICO.
- The DME approach significantly boosts ICO refrigerator efficiency.
- Paves the way for developing practical quantum refrigerators.
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