Spin-orbital entanglement near quantum phase transitions

TL;DR

This paper investigates spin-orbital entanglement in a one-dimensional model, revealing continuous quantum phase transitions and similarities in entanglement at specific symmetry points, using exact diagonalization methods.

Contribution

It provides new insights into the nature of quantum phase transitions and entanglement in spin-orbital models, highlighting differences from pure spin systems.

Findings

Quantum entanglement is similar at the SU(4) symmetry point and in the valence bond state.

Quantum transitions can be continuous in spin-orbital models, unlike in pure spin models.

Exact diagonalization was used to analyze finite chains.

Abstract

Spin-orbital entanglement in the ground state of a one-dimensional SU(2)$\otimes$SU(2) spin-orbital model is analyzed using exact diagonalization of finite chains. For $S=1/2$ spins and $T=1/2$ pseudospins one finds that the quantum entanglement is similar at the SU(4) symmetry point and in the spin-orbital valence bond state. We also show that quantum transitions in spin-orbital models turn out to be continuous under certain circumstances, in constrast to the discontinuous transitions in spin models with SU(2) symmetry.