Dephasing with strings attached

TL;DR

This paper compares quantum transport in particle and domain wall models under weak dephasing, revealing similar bulk responses but distinct spectral broadening in finite systems, relevant to various physical systems.

Contribution

It provides an exact comparison of quantum dynamics for particles and domain walls under dephasing, highlighting differences in spectral broadening in finite chains.

Findings

Bulk transport responses are nearly identical for both models.

Finite chains show more spectral broadening for domain walls.

Results are relevant to quasi-1D antiferromagnets and polymer chains.

Abstract

Motivated by the existence of mobile low-energy excitations like domain walls in one dimension or gauge-charged fractionalized particles in higher dimensions, we compare quantum dynamics in the presence of weak Markovian dephasing for a particle hopping on a chain and for an Ising domain wall whose motion leaves behind a string of flipped spins. Exact solutions show that the two models have near identical transport responses in the bulk. On the other hand, in finite-length chains, the broadening of discrete spectral lines is much more noticeable in the case of a domain wall. These results may be of relevance to a broad class of systems including quasi-1D antiferromagnets, polymer chains, and even retinal systems.