Integrable spin chains with random interactions

TL;DR

This paper investigates a Yang-Baxter integrable quantum spin-1/2 chain with random interactions, demonstrating persistent ballistic energy and spin transport due to the model's integrability and free fermion characteristics.

Contribution

It introduces a new integrable spin chain with random interactions and shows that it exhibits non-localized, ballistic transport properties even under certain deformations.

Findings

Energy eigenstates are never localized.

The model exhibits perfect energy and spin transport at all temperatures.

Ballistic behavior persists under specific deformations that break integrability.

Abstract

We study a Yang-Baxter integrable quantum spin-1/2 chain with random interactions. The Hamiltonian is local and involves two and three-spin interactions with random parameters. We show that the energy eigenstates of the model are never localized and in fact exhibit perfect energy and spin transport at both zero and infinite temperatures. By considering the vicinity of a free fermion point in the model we demonstrate that this behavior persists under deformations that break integrability but preserve the free fermion nature of the Hamiltonian. In this case the ballistic behavior can be understood as arising from the correlated nature of the disorder in the model. We conjecture that the model belongs to a broad class of models avoiding localization in 1D.