Violating the thermodynamic uncertainty relation in the three-level maser

Summary, in English

Nanoscale heat engines are subject to large fluctuations which affect their precision. The thermodynamic uncertainty relation (TUR) provides a trade-off between output power, fluctuations, and entropic cost. This trade-off may be overcome by systems exhibiting quantum coherence. This Letter provides a study of the TUR in a prototypical quantum heat engine, the Scovil–Schulz-DuBois maser. Comparison with a classical reference system allows us to determine the effect of quantum coherence on the performance of the heat engine. We identify analytically regions where coherence suppresses fluctuations, implying a quantum advantage, as well as regions where fluctuations are enhanced by coherence. This quantum effect cannot be anticipated from the off-diagonal elements of the density matrix. Because the fluctuations are not encoded in the steady state alone, TUR violations are a consequence of coherence that goes beyond steady-state coherence. While the system violates the conventional TUR, it adheres to a recent formulation of a quantum TUR. We further show that parameters where the engine operates close to the conventional limit are prevalent and TUR violations in the quantum model are not uncommon.

• Author: Alex Arash Sand Kalaee; Andreas Wacker; Patrick Potts
• Department/s: Mathematical Physics; NanoLund: Center for Nanoscience
• Publishing year: 2021
• Language: English
• Publication/Series: Physical Review E
• Volume: 104
• Issue: 1
• Links: http://dx.doi.org/10.1103/PhysRevE.104.L012103
• Document type: Journal article
• Publisher: American Physical Society
• Topic: Physical Sciences
• Status: Published
• Project: KAW Project: Nanothermodynamics for optoelectronic semiconductor devices
• ISBN/ISSN/Other: ISSN: 2470-0045