Magnetism and quantum phase transitions in spin-1/2 attractive fermions with polarization

TL;DR

This paper provides a detailed analysis of magnetic properties and quantum phase transitions in one-dimensional spin-1/2 attractive fermions with polarization, using Bethe ansatz and dressed energy formalism, revealing universal magnetic behavior.

Contribution

It introduces an iteration method for higher order corrections and confirms the accuracy of analytic expressions for physical quantities across coupling regimes.

Findings

Analytic expressions match numerical solutions in weak and strong coupling regimes.

Magnetization exhibits linear field-dependent behavior universally across the attractive regime.

Phase diagrams accurately depict quantum phase transitions in polarized fermions.

Abstract

An extensive investigation is given for magnetic properties and phase transitions in one-dimensional Bethe ansatz integrable spin-1/2 attractive fermions with polarization by means of the dressed energy formalism. An iteration method is presented to derive higher order corrections for the ground state energy, critical fields and magnetic properties. Numerical solutions of the dressed energy equations confirm that the analytic expressions for these physical quantities and resulting phase diagrams are highly accurate in the weak and strong coupling regimes, capturing the precise nature of magnetic effects and quantum phase transitions in one-dimensional interacting fermions with population imbalance. Moreover, it is shown that the universality class of linear field-dependent behaviour of the magnetization holds throughout the whole attractive regime.