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Joint measurability in nonequilibrium quantum thermodynamics.
Konstantin Beyer1, Roope Uola2, Kimmo Luoma1,3
1Institut für Theoretische Physik, Technische Universität Dresden, D-01062 Dresden, Germany.
Physical Review. E
|September 16, 2022
Summary
This study explores quantum work and fluctuation theorems, showing that generalized unsharp measurements overcome previous limitations. This allows for accurate quantum work and free energy difference calculations using a Jarzynski equality.
Area of Science:
- Quantum Mechanics
- Statistical Mechanics
- Quantum Measurement Theory
Background:
- Quantum work and fluctuation theorems are often analyzed using projective two-point measurement (TPM) schemes.
- A known no-go theorem prevents work observables from satisfying both average work conditions and TPM statistics for diagonal input states with projective measurements.
Purpose of the Study:
- To extend the framework of quantum work and fluctuation theorems beyond restrictive projective measurements.
- To investigate the measurability of quantum work using generalized unsharp measurements.
- To determine the information extractable about work and fluctuations from these generalized measurements.
Main Methods:
- Investigated quantum work and fluctuation theorems within quantum measurement theory.
- Extended the analysis from projective two-point measurement (TPM) schemes to unsharp measurements.
- Demonstrated that the no-go theorem is circumvented when observables are jointly measurable for intermediate unitary evolution.
Main Results:
- The no-go theorem for quantum work observables does not hold under generalized joint measurability conditions.
- A model with unsharp energy measurements was constructed, defining visibility bounds for joint measurability.
- Unsharp measurements enable the construction of a single apparatus for accurate average work determination and free energy difference calculation via Jarzynski equality.
Conclusions:
- Unsharp quantum measurements offer a more flexible and experimentally viable approach to studying quantum work and fluctuations.
- Generalized measurements overcome fundamental limitations of projective measurements in this context.
- This work provides a pathway for experimentally accessing quantum work statistics and related thermodynamic quantities.
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