Orbital Optical Raman Lattice

TL;DR

This paper proposes a new orbital optical Raman lattice scheme to explore exotic high-orbital Bose condensates with synthetic spin-orbit coupling, revealing novel topological quantum phases influenced by SOC and orbital interactions.

Contribution

It introduces a novel orbital optical Raman lattice scheme combining spin-orbit coupling and high orbital bands to study new quantum phases in optical lattices.

Findings

Discovery of a uniform angular momentum superfluid phase with topological chiral orbital current.

Identification of a two-dimensional topological spin-orbital supersolid phase with density wave patterns.

Observation of topological excitations with opposite Chern numbers protecting edge modes.

Abstract

Spin and orbital are two basic degrees of freedom that play significant roles in exploring exotic quantum phases in optical lattices with synthetic spin-orbit coupling (SOC) and high orbital bands, respectively. Here, we combine these two crucial ingredients for the first time by proposing a completely new orbital optical Raman lattice scheme to explore exotic high-orbital Bose condensates with Raman-induced SOC in a square lattice. We find that both the SOC and p-orbital interactions influence the condensed state of bosons. Their interplay results in two novel high-orbital many-body quantum phases: the uniform angular momentum superfluid phase, which exhibits a global topological chiral orbital current characterized by a uniform Chern number, and the two-dimensional topological spin-orbital supersolid phase, which is characterized by the spin and orbital angular momentum density wave patterns and topological excitations with opposite Chern numbers, respectively protecting the chiral and antichiral edge modes in the neighboring supersolid clusters. Our scheme may open a new avenue for exploring exotic SOC and high-orbital physics in optical lattices, and is expected to advance the experimental realization of novel supersolids in higher dimensions.