Hidden XY structure of the bond-charge Hubbard model

TL;DR

This paper maps the bond-charge Hubbard model in the superconducting regime onto the XY model, analyzing correlations and phase boundaries, and identifying the transition line with the XY model's factorization line.

Contribution

It provides an analytical mapping and phase analysis of the bond-charge Hubbard model using the XY model framework, aligning with numerical results.

Findings

Excellent agreement between analytical and numerical results

Identification of the superconducting transition line with the XY model's factorization line

Mapping reveals the XY structure of the bond-charge Hubbard model

Abstract

The repulsive one-dimensional Hubbard model with bond-charge interaction (HBC) in the superconducting regime is mapped onto the spin-1/2 XY model with transverse field. We calculate correlations and phase boundaries, realizing an excellent agreement with numerical results. The critical line for the superconducting transition is shown to coincide with the analytical factorization line identifying the commensurate-incommensurate transition in the XY model.