Progress Towards Realizing One-Dimensional Spin-Orbit-Coupled Bose Gases

One-dimensional (1D) quantum systems subject to gauge fields are important platforms to explore novel correlated quantum states yet remain largely unexplored in experiments. Without gauge fields, quantum systems at low energies are generally described by Luttinger liquids whose behavior strongly depends on interparticle interactions. However, spin-orbit coupling (SOC) can notably modify the energy-momentum dispersion, leading to the emergence of unconventional Luttinger liquids whose behavior depends on both SOC and interactions. In experiments, we plan to set up a 2D optical lattice to generate an array of 1D tubes. In addition, 1D SOC along the tube direction is created by a pair of counter-propagating Raman laser beams to atoms. This setup will allow us to explore the equilibrium and excited states of 1D Bose gases subject to SOC at various Raman coupling strengths and interactions. For instance, we can measure atoms' momentum distribution to obtain the single-particle correlation function. Such a correlation is expected to decay exponentially at a critical Raman coupling strength even in the weakly interacting regime, indicating the emergence of non-Luttinger liquids that do not exhibit a quasi-long-range order.