Minimal quantum thermal machine in a bandgap environment: non-Markovian features and anti-Zeno advantage

TL;DR

This paper investigates a minimal quantum thermal machine with a bandgap environment, revealing non-Markovian effects and an anti-Zeno advantage that enhance performance beyond standard Markovian predictions.

Contribution

It provides a comprehensive analysis of a quantum thermal machine in a bandgap environment, highlighting non-Markovian dynamics and quantum advantages under fast modulation.

Findings

Power boost due to quantum effects during fast modulation

Non-Markovian correlations enhance spectral response

Anti-Zeno effect improves heat engine performance

Abstract

A minimal model of a quantum thermal machine is analyzed, where a driven two level working medium (WM) is embedded in an environment (reservoir) whose spectrum possesses bandgaps. overlap with hot or cold reservoirs whose spectra are separated by a bandgap. Approximate and exact treatments supported by analytical considerations yield a complete characterization of this thermal machine in the deep quantum domain. For slow to moderate modulation, the spectral response of the reservoirs is close to equilibrium, exhibiting sideband (Floquet) resonances in the heat currents and power output. In contrast, for faster modulation, strong-coupling and non-Markovian features give rise to correlations between the WM and the reservoirs and between the two reservoirs. Power boost of strictly quantum origin ('quantum advantage') is then found for both continuous and segmental fast modulation that leads to the anti-Zeno effect of enhanced spectral reservoir response. Such features cannot be captured by standard Markovian treatments.