Berry-Phase induced Heat Pumping and its Impact on the Fluctuation Theorem

TL;DR

This paper explores how Berry-phase effects influence quantum heat transfer in molecular junctions, revealing a geometric contribution to heat flux and conditions under which fluctuation theorems break down or are restored.

Contribution

It introduces the concept of Berry-phase induced heat pumping in quantum systems and identifies conditions for the fluctuation theorem to hold or break down.

Findings

Identification of a geometric phase contribution to heat flux.

Discovery of a fractional quantized geometric phonon response.

Conditions for restoring the fluctuation theorem in quantum heat transfer.

Abstract

Applying adiabatic, cyclic two parameter modulations we investigate quantum heat transfer across an anharmonic molecular junction contacted with two heat baths. We demonstrate that the pumped heat typically exhibits a Berry phase effect in providing an additional geometric contribution to heat flux. Remarkably, a robust fractional quantized geometric phonon response is identified as well. The presence of this geometric phase contribution in turn causes a breakdown of the fluctuation theorem of the Gallavotti-Cohen type for quantum heat transfer. This can be restored only if (i) the geometric phase contribution vanishes and if (ii) the cyclic protocol preserves the detailed balance symmetry.