Fermionic random transverse-field Ising spin chain

TL;DR

This paper studies the effects of charge fluctuations on the quantum critical behavior of a fermionic transverse-field Ising spin chain, revealing nonmonotonous correlations and phase diagram modifications.

Contribution

It introduces analysis of charge fluctuation effects in the fermionic Ising chain, highlighting the emergence of a quantum critical region influenced by chemical potential.

Findings

Quantum critical region appears at finite chemical potential.

Nonmonotonous temperature dependence of spin correlations observed.

One-fermion density of states analyzed in the model.

Abstract

The interplay of spin and charge fluctuations in the random transverse-field Ising spin chain on the fermionic space is investigated. The finite chemical potential, which controls the charge fluctuations, leads to the appearance of the quantum critical region in the phase diagram where the magnetic correlations are quenched by nonmagnetic sites. Regions of nonmonotonous temperature dependence of spin-spin correlation length appear at nonzero $\mu$. The results on the one-fermion density of states of the model are discussed.