Excited states in Bethe ansatz solvable models and the dressing of spin and charge

TL;DR

This paper develops a formalism to analyze excitations in Bethe ansatz solvable models, deriving temperature-dependent dressed energies and momenta, and explores spin-charge separation phenomena, especially in electronic models and Hubbard-Shastry models.

Contribution

It introduces a general formalism for excitations in Bethe ansatz models, including temperature effects and detailed analysis of Hubbard-Shastry models.

Findings

Dressed energies, momenta, spin, and charge are obtained at nonzero temperature.

Dressed spin and charge are generally momentum dependent.

Spin-charge separation occurs only at zero temperature in certain electronic models.

Abstract

A general formalism for the study of excitations above equilibrium in Bethe ansatz solvable models is presented. Nonzero temperature expressions for dressed energy, momentum, spin and charge are obtained, and it is found that the dressed spin and charge are in general momentum dependent. For an electronic model one may only have spin-charge separation at zero temperature where the ground state is half-filled and has zero magnetisation. Finally, the excitations of the Hubbard-Shastry models are examined in detail.