Energy drag in particle-hole symmetric systems as a quantum quench

TL;DR

This paper investigates thermal drag in particle-hole symmetric systems, revealing a non-Fermi's Golden Rule growth at short times and analyzing long-time behavior using the Hubbard model's integrability.

Contribution

It demonstrates that thermal drag persists in particle-hole symmetric systems and provides a detailed analysis of its dynamics through quantum quenches, including long-time limits.

Findings

Thermal drag does not vanish in particle-hole symmetric systems.

Short-time growth of thermal drag exhibits non-Fermi's Golden Rule behavior.

Long-time behavior analyzed using the integrability of the Hubbard model.

Abstract

Two conducting quantum systems coupled only via interactions can exhibit the phenomenon of Coulomb drag, in which a current passed through one layer can pull a current along in the other. However, in systems with particle-hole symmetry -- for instance, the half-filled Hubbard model or graphene near the Dirac point -- the Coulomb drag effect vanishes to leading order in the interaction. Its thermal analogue, whereby a thermal current in one layer pulls a thermal current in the other, does not vanish and is indeed the dominant form of drag in particle-hole symmetric systems. By studying a quantum quench, we show that thermal drag, unlike charge drag, displays a non-Fermi's Golden Rule growth at short times due to a logarithmic scattering singularity generic to one dimension. Exploiting the integrability of the Hubbard model, we obtain the long-time limit of the quench for weak interactions. Finally, we comment on thermal drag effects in higher dimensional systems.