Dynamical control of quantum heat engines using exceptional points

Dynamical control of quantum heat engines using exceptional points

Abstract A quantum thermal machine is an open quantum system coupled to hot and cold thermal baths. Thus, its dynamics can be well understood using the concepts and tools from non-Hermitian quantum systems. A hallmark of non-Hermiticity is the existence of exceptional points where the eigenvalues of...

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Bibliographic Details
Published in:Nature communications 2022-10, Vol.13 (1), p.6225-6225, Article 6225
Main Authors: Zhang, J.-W., Zhang, J.-Q., Ding, G.-Y., Li, J.-C., Bu, J.-T., Wang, B., Yan, L.-L., Su, S.-L., Chen, L., Nori, F., Özdemir, Ş. K., Zhou, F., Jing, H., Feng, M.
Format: Article
Language:eng
Subjects:
Baths
Coherence
Eigenvalues
Eigenvectors
Gasoline engines
Heat engines
Otto cycle
Quantum theory
Thermal baths
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Summary:Abstract A quantum thermal machine is an open quantum system coupled to hot and cold thermal baths. Thus, its dynamics can be well understood using the concepts and tools from non-Hermitian quantum systems. A hallmark of non-Hermiticity is the existence of exceptional points where the eigenvalues of a non-Hermitian Hamiltonian or a Liouvillian superoperator and their associated eigenvectors coalesce. Here, we report the experimental realization of a single-ion heat engine and demonstrate the effect of Liouvillian exceptional points on the dynamics and the performance of a quantum heat engine. Our experiments have revealed that operating the engine in the exact- and broken-phases, separated by a Liouvillian exceptional point, respectively during the isochoric heating and cooling strokes of an Otto cycle produces more work and output power and achieves higher efficiency than executing the Otto cycle completely in the exact phase where the system has an oscillatory dynamics and higher coherence. This result opens interesting possibilities for the control of quantum heat engines and will be of interest to other research areas that are concerned with the role of coherence and exceptional points in quantum processes and in work extraction by thermal machines.
ISSN:2041-1723
2041-1723