Topological Higgs Amplitude Modes in Strongly Interacting Superfluids

TL;DR

This paper demonstrates the existence of topological Higgs amplitude modes in a strongly interacting superfluid modeled by the 2D Su-Schrieffer-Heeger-Bose-Hubbard system, revealing their nontrivial topology and potential for new physical insights.

Contribution

It introduces the first realization of topological Higgs modes in a strongly interacting superfluid, using the slave boson approach and effective action analysis.

Findings

Higgs and Goldstone modes are decoupled at large fillings with inherited topology.

Topological Higgs modes persist at finite fillings despite coupling with Goldstone modes.

The study provides a universal physical picture for the topological nature of these modes.

Abstract

By studying the 2-dimensional Su-Schrieffer-Heeger-Bose-Hubbard model, we show the existence of topological Higgs amplitude modes in the strongly interacting superfluid phase. Using the slave boson approach, we find that, in the large filling limit, the Higgs excitations and the Goldstone excitations above the ground state are well decoupled, and both of them exhibit nontrivial topology inherited from the underlying noninteracting bands. At finite fillings, they become coupled at high energies; nevertheless, the topology of these modes are unchanged. Moreover, based on an effective action analysis, we further provide a universal physical picture for the topological character of Higgs and Goldstone modes. Our discovery of the first realization of the topological Higgs mode opens the path to novel investigations in various systems such as superconductors and quantum magnetism.