# Dual Effects of Lamb Shift in Quantum Thermodynamical Systems

## TL;DR

This paper shows how the Lamb shift, a small energy correction in quantum systems, can significantly affect heat transport in quantum thermodynamics.

## Contribution

The study reveals the dual and non-trivial effects of the Lamb shift on steady-state heat currents in quantum systems.

## Key findings

- The Lamb shift suppresses heat current at small temperature gradients.
- At large gradients, heat current diverges when the Lamb shift is included.
- The Lamb shift sets an upper bound on heat current in the absence of the shift.

## Abstract

The Lamb shift, as an additional energy correction induced by environments usually, has a marginal contribution and hence is neglected. We demonstrate that the Lamb shift, which modifies the energy levels, can influence the heat current to varying extents. We focus on the steady-state heat current through two coupled two-level atoms, respectively, in contact with a heat reservoir at a certain temperature. We find that the Lamb shift suppresses the steady-state heat current at small temperature gradients, while at large gradients, the heat current is restricted by an upper bound without the Lamb shift but diverges when it is included. These results not only demonstrate the Lamb shift’s critical role in quantum heat transport but also advance our understanding of its impact in quantum thermodynamics.