Density-Dependent Gauge Field with Raman Lattices

TL;DR

This paper proposes a method to create density-dependent gauge fields in ultracold atoms using Raman lattices, revealing novel phases and bound states through theoretical analysis and suggesting experimental implementation.

Contribution

It introduces a simple scheme to engineer density-dependent gauge fields in a Bose-Hubbard model with spin-orbit coupling, and explores its many-body phases and bound states.

Findings

Identification of three phases: Mott insulator, superfluid, and magnetic superfluid.

Discovery of deep two-body bound states due to large spin-flipped tunneling.

Feasible experimental protocol using existing Raman lattice platforms.

Abstract

The study of the gauge field is an everlasting topic in modern physics. Spin-orbit coupling is a powerful tool in ultracold atomic systems, resulting in an artificial gauge field that can be easily manipulated and observed in a tabletop environment. Combining optical Raman lattices and atom-atom interaction, the artificial gauge field can be made density-dependent. In this work, we propose a straightforward way to engineer one-dimensional density-dependent gauge field in a Bose-Hubbard model in spin-orbit coupled Raman lattices. Next, we study the model from two perspectives: few-body quantum walk dynamics and many-body ground state. In the first perspective, we show that large spin-flipped tunneling can lead to a deep two-body bound state. In the second perspective, mean-field and density matrix renormalization group (DMRG) calculations consistently reveal three different phases, i.e. the Mott insulator phase, the superfluid phase, and the magnetic superfluid phase. Finally, we discuss the experimental protocol with Raman lattices based on existing experimental platforms.