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Heat and Work Along Individual Trajectories of a Quantum Bit
M Naghiloo1, D Tan1,2, P M Harrington1
1Department of Physics, Washington University, St. Louis, Missouri 63130, USA.
Physical Review Letters
|April 4, 2020
Summary
Researchers tracked quantum state trajectories of a driven superconducting qubit. They verified the first law of thermodynamics for open quantum systems by distinguishing heat and work in individual quantum trajectories.
Area of Science:
- Quantum physics
- Thermodynamics
- Superconducting circuits
Background:
- Understanding quantum thermodynamics is crucial for developing quantum technologies.
- Open quantum systems offer a platform to study fundamental thermodynamic principles at the quantum level.
Purpose of the Study:
- To experimentally track individual quantum state trajectories of a driven qubit.
- To verify the first law of thermodynamics for an open quantum system by distinguishing heat and work.
- To validate findings using theoretical models and advanced measurement schemes.
Main Methods:
- Utilized a near quantum limited detector to monitor quantum state trajectories.
- Employed a superconducting transmon circuit hybridized with a waveguide cavity.
- Implemented a quantum feedback loop to isolate the qubit and compensate for heat exchange.
Main Results:
- Successfully tracked individual quantum coherent trajectories of the driven qubit.
- Experimentally distinguished energy changes into heat and work for each trajectory.
- Verified the first law of thermodynamics for the open quantum system.
Conclusions:
- The study provides experimental evidence for the first law of thermodynamics in open quantum systems at the single-trajectory level.
- The results are consistent with theoretical predictions from master equation and two-projective-measurement schemes.
- Demonstrated the utility of quantum feedback for controlling and measuring open quantum systems.
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