Suppression of Quasi-long-range Order in One-Dimensional Spin-Orbit-Coupled Bose Gases*

The coherence of a quantum system is one of the key signatures of many-body physics. Unlike three-dimensional Bose-Einstein Condensates, which have true long-range coherence, for Bose gases confined in a one-dimensional (1D) potential, the coherence has quasi-long-range order, revealing a characteristic property of superfluid. We experimentally show that the quasi-long-range coherence of 1D Bose gases can be suppressed by applying 1D synthetic spin-orbit coupling (SOC), which is generated by a pair of counter-propagating Raman beams. This suppression is demonstrated by analyzing the one-body correlation function. By varying the coupling strength of SOC towards a critical value, we observe a transformation from power-law decay of the one-body correlation function, indicating quasi-long-range order of the system, to exponential decaying form.