Local susceptibilities in semi-infinite antiferromagnet chains: elementary perspectives

TL;DR

This paper discusses how semi-infinite antiferromagnetic chains exhibit local susceptibility alternation, a phenomenon observable in quantum and classical models, explained through conformal field theory and classical expansions.

Contribution

It highlights the universality of susceptibility alternation in various spin chain models, bridging quantum and classical perspectives.

Findings

Susceptibility alternation occurs in quantum and classical chains.

Alternation is observable in models expanded around the Ising limit.

The phenomenon is not solely quantum but also classical in nature.

Abstract

Using conformal field theory methods Eggert and Affleck have shown that the semi-infinite S=1/2 Heisenberg antiferromagnetic chain exhibits a remarkable alternation in its local response to a uniform field at low temperatures. Such alternation is not an essentially quantum effect: similar, and sometimes stronger, susceptibility alternation is a feature of classical Heisenberg-Ising chains at T=0. In S=1/2 chains, susceptibility alternation is not unique to the Heisenberg model, but can be seen in expansions about the Ising model and also in the XY model.