Symmetry-protected topological phase transition in one-dimensional Kondo lattice and its realization with ultracold atoms

TL;DR

This paper proposes a way to realize and study a symmetry-protected topological phase transition in a one-dimensional Kondo lattice using ultracold atoms, combining theoretical approaches to understand the phase diagram.

Contribution

It introduces a model for ultracold atoms in optical lattices that hosts a topological phase transition, analyzing symmetry protection via bosonization and strong-coupling methods.

Findings

Identification of a controllable SPT phase transition in a Kondo lattice model.

Demonstration of a crossover from fermionic to bosonic SPT phases.

Clarification of symmetry roles in the phase diagram.

Abstract

We propose that ultracold alkaline-earth-like atoms confined in one-dimensional optical lattice can realize a Kondo lattice model which hosts a symmetry-protected topological (SPT) phase and an associated quantum phase transition in a controllable manner. The symmetry protection of the phase transition is discussed from two different viewpoints: topological properties related to spatial patterns of Kondo singlets, and symmetry eigenvalues of the spin states. We uncover the role of various symmetries in the phase diagram of this system by combining a weak-coupling approach by Abelian bosonization and strong-coupling pictures of ground states. Furthermore, we show that the bosonization approach correctly describes a crossover from a fermionic SPT phase to a bosonic SPT phase and an associated change of protecting symmetries as the charge degrees of freedom are frozen by the Hubbard repulsion.