# Bounds on ﬂuctuations for ensembles of quantum thermal machines

@article{Gerry2022BoundsOFL,
title={Bounds on ﬂuctuations for ensembles of quantum thermal machines},
author={Matthew Gerry and Na’im Kalantar and Dvira Segal},
journal={Journal of Physics A: Mathematical and Theoretical},
year={2022}
}
• Published 8 September 2021
• Physics
• Journal of Physics A: Mathematical and Theoretical
We study universal aspects of fluctuations in an ensemble of noninteracting continuous quantum thermal machines in the steady state limit. Considering an individual machine, such as a refrigerator, in which relative fluctuations (and high order cumulants) of the cooling heat current to the absorbed heat current, $\eta^{(n)}$, are upper-bounded, $\eta^{(n)}\leq \eta_C^n$ with $n\geq 2$ and $\eta_C$ the Carnot efficiency, we prove that an {\it ensemble} of $N$ distinct machines similarly…

## References

SHOWING 1-10 OF 58 REFERENCES
Quantum supremacy of many-particle thermal machines
• Physics
• 2016
While the emergent field of quantum thermodynamics has the potential to impact energy science, the performance of thermal machines is often classical. We ask whether quantum effects can boost the
Experimental Characterization of a Spin Quantum Heat Engine.
A quantum heat engine based on a spin-1/2 system and nuclear magnetic resonance techniques is experimentally implemented, able to reach an efficiency for work extraction very close to its thermodynamic limit.
Qubit absorption refrigerator at strong coupling
• Physics
• 2017
We demonstrate that a quantum absorption refrigerator can be realized from the smallest quantum system, a qubit, by coupling it in a non-additive (strong) manner to three heat baths. This function is
Thermodynamic uncertainty relation in quantum thermoelectric junctions.
• Physics, Medicine
Physical review. E
• 2019
It is demonstrated that the TUR always holds in noninteracting thermoelectric generators when approaching the thermodynamic efficiency limit, and focuses on the resonant transport regime to determine the parameter range in which the violation of the T UR can be observed.
Current fluctuations in quantum absorption refrigerators.
• D. Segal
• Physics, Medicine
Physical review. E
• 2018
This work explains how to obtain the complete cumulant generating function of the refrigerator in a steady state, then derive a partial cumulants generating function, which yields closed-form expressions for both the averaged cooling current and its noise.
Quantum heat current under non-perturbative and non-Markovian conditions: Applications to heat machines.
• Physics, Medicine
The Journal of chemical physics
• 2016
It is found that CASBIs are necessary to maintain the consistency of the heat current with thermodynamic laws in the case of strong system-bath coupling, and this point is demonstrated for a non-equilibrium spin-boson model and a three-level heat engine model using the reduced hierarchal equations of motion approach.
Quantum-enhanced absorption refrigerators
• Computer Science, Medicine
Scientific reports
• 2014
This work establishes thermodynamic performance bounds for quantum absorption refrigerators and investigates their quantum origin, and shows how those bounds may be pushed beyond what is classically achievable, by suitably tailoring the environmental fluctuations via quantum reservoir engineering techniques.
Efficiency fluctuations in quantum thermoelectric devices
• Physics
• 2015
We present a method, based on characterizing efficiency fluctuations, to assess the performance of nanoscale thermoelectric junctions. This method accounts for effects typically arising in small
Scaling-Up Quantum Heat Engines Efficiently via Shortcuts to Adiabaticity
• Computer Science, Physics
Entropy
• 2016
This work proposes to scale up a quantum heat engine utilizing a many-particle working medium in combination with the use of shortcuts to adiabaticity to boost the nonadiabatic performance by eliminating quantum friction and reducing the cycle time.
Collective performance of a finite-time quantum Otto cycle.
• Physics, Medicine
Physical review. E
• 2019
It is demonstrated that the quantum phase transitions for the ground and excited states may have a strong negative effect on the performance of the machine and by analyzing the work output, one can distinguish between the operational regimes with and without a phase transition.