Bosonization study of quantum phase transitions in the one-dimensional asymmetric Hubbard model

TL;DR

This paper uses bosonization to analytically study quantum phase transitions in a 1D asymmetric Hubbard model, revealing how hopping integral differences drive phase separation.

Contribution

It provides an analytical framework for understanding phase transitions in the asymmetric Hubbard model, highlighting the role of hopping asymmetry.

Findings

Hopping integral difference is crucial for phase separation.

Phase transition conditions from density wave to phase separation are derived.

Large hopping asymmetry induces phase separation even with weak interactions.

Abstract

The quantum phase transitions in the one-dimensional asymmetric Hubbard model are investigated with the bosonization approach. The conditions for the phase transition from density wave to phase separation, the correlation functions and their exponents are obtained analytically. Our results show that the difference between the hopping integrals for up- and down-spin electrons is crucial for the happening of the phase separation. When the difference is large enough, the phase separation will appear even if the on-site interaction is small.