Bogoliubov excitations in a Bose–Hubbard model on a hyperhoneycomb lattice

Abstract

We study the topological properties of Bogoliubov excitation modes in a Bose-Hubbard model of three-dimensional (3D) hyperhoneycomb lattices. For the non-interacting case, there exist nodal loop excitations in the Bloch bands. As the on-site repulsive interaction increases, the system is first driven into the superfluid phase and then into the Mott-insulator phase. In both phases, the excitation bands exhibit robust nodal-loop structures and bosonic surface states. From a topology point of view, these nodal-loop excitation modes may be viewed as a permanent fingerprint left in the Bloch bands.

Collapses-revivals phenomena induced by weak magnetic flux in diamond chain*

“…Degenerate energy levels can be split and the gap between different energy bands can be opened by a perturbation embeded in a diamond chain, [5][6][7][8][9] such as synthetic gauge field, which provides a new potential for ultracold atom to simulate intriguing quantum phenomena in traditional condensed matter physics. [10][11][12][13] Optical lattice is a key platform to investigate the quantum behaviors by twisted bilayer graphene model, [14] Haldane model, [15] Kane-Mele model, [16] and Hofstadter butterfly model. [17][18][19] As is known, particles exhibit Bloch oscillations in an optical lattice (periodic potential field).…”

Topological gapless matters in three-dimensional ultracold atomic gases

“…Furthermore, Weyl fermion quasiparticles were shown to emerge in a 3D system of polar particles in magnetic fields 30 and in a topological density wave phase in cold atomic Rydberg-dressed atomic fermions 24 . Similar to the fermionic excitations, Weyl points and nodal rings were also shown to emerge in Bogoliubov excita-tions of bosonic superfluid and Mott insulator phases when bosonic atoms are loaded into a Weyl semimetal or nodal ring optical lattice [149][150][151] .…”