Ergodicity of the extended anisotropic 1D Heisenberg model: response at low temperatures

TL;DR

This paper investigates the ergodic properties of the extended anisotropic 1D Heisenberg model at low temperatures, showing divergence of susceptibility in certain non-ergodic regions through exact diagonalization.

Contribution

It provides a detailed analysis of ergodicity and susceptibility divergence in the extended anisotropic Heisenberg model using exact diagonalization.

Findings

Susceptibility diverges as temperature approaches zero in non-ergodic regions.

Ergodicity considerations are crucial for understanding low-temperature behavior.

Finite clusters and bulk systems exhibit similar divergence patterns.

Abstract

We present the results of exact diagonalization calculations of the isolated and isothermal on-site static susceptibilities in the anisotropic extended Heisenberg model on a linear chain with periodic boundary conditions. Based on the ergodicity considerations we conclude that the isothermal susceptibility will diverge as $T\to 0$ both in finite clusters and in the bulk system in two non-ergodic regions of the phase diagram of the system.