报告题目：A stripe phase with supersolid properties in spin-orbit coupled Bose-Einstein condensates

报 告 人：Junru Li

报告时间：2017-12-4 10:00

报告地点：理科楼C302

报告摘要： Supersolidity combines superfluid flow with long-range spatial periodicity of solids, two properties that are often mutually exclusive. The original discussion of quantum crystals and supersolidity focused on solid 4He and triggered extensive experimental efforts. The concept of supersolidity was then generalized from quantum crystals to other superfluid systems that break continuous translational symmetry. Bose-Einstein condensates with spin-orbit coupling are predicted to possess a stripe phase which carries such supersolid properties.

I will talk about our recent work on realizing spin-orbit coupling with ultracold atoms and the associated stripe phase in an optical superlattice. We proposed a new scheme for realizing the spin-orbit coupling in an optical superlattice where the orbital degree of freedom is used as the pseudospin.

We demonstrated the feasibility of such scheme and observed the predicted density modulation of this stripe phase using Bragg reflection (which provides evidence for spontaneous long-range order in one direction) while maintaining a sharp momentum distribution (the hallmark of superfluid Bose-Einstein condensates). Our work thus establishes a system with supersolid properties, namely, continuous symmetry-breaking properties and superfluid behaviour.