Weyl Bogoliubov excitations in Bose-Hubbard extension of Weyl semimetal

TL;DR

This paper introduces a Bose-Hubbard model extension of Weyl semimetals for ultracold atoms, revealing Weyl-like excitations and phase diagrams with superfluid and Mott insulator phases, and analyzing quasiparticle spectra.

Contribution

It presents a novel Bose-Hubbard extension of Weyl semimetals with detailed phase diagrams and excitation properties, bridging electronic and bosonic topological systems.

Findings

Identification of Weyl nodes in Bogoliubov excitations

Surface arc phenomena in bosonic systems

Quasiparticle spectra touching at Weyl points

Abstract

In this paper, a Bose-Hubbard extension of a Weyl semimetal is proposed that can be realized for ultracold atoms using laser assisted tunneling and Feshbach resonance technique in three dimensional optical lattices. The global phase diagram is obtained consisting of a superfluid phase and various Mott insulator phases by using Landau theory. The Bogoliubov excitation modes for the weakly interacting case have nontrivial properties (Weyl nodes, bosonic surface arc, etc.) analogs of those in Weyl semimetals of electronic systems, which are smoothly carried over to that of Bloch bands for the noninteracting case. The properties of the insulating phases for the strongly interacting case are explored by calculating both the quasiparticle and quasihole dispersion relation, which shows two quasiparticle spectra touch at Weyl nodes.