Department of Physics, Stanford University, Stanford, California 94305, USA.
E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA.
Phys Rev Lett. 2019 Oct 18;123(16):160404. doi: 10.1103/PhysRevLett.123.160404.
We realize the dynamical 1D spin-orbit coupling (SOC) of a Bose-Einstein condensate confined within an optical cavity. The SOC emerges through spin-correlated momentum impulses delivered to the atoms via Raman transitions. These are effected by classical pump fields acting in concert with the quantum dynamical cavity field. Above a critical pump power, the Raman coupling emerges as the atoms superradiantly populate the cavity mode with photons. Concomitantly, these photons cause a backaction onto the atoms, forcing them to order their spin-spatial state. This SOC-inducing superradiant Dicke phase transition results in a spinor-helix polariton condensate. We observe emergent SOC through spin-resolved atomic momentum imaging and temporal heterodyne measurement of the cavity-field emission. Dynamical SOC in quantum gas cavity QED, and the extension to dynamical gauge fields, may enable the creation of Meissner-like effects, topological superfluids, and exotic quantum Hall states in coupled light-matter systems.
我们实现了束缚在光腔内的玻色-爱因斯坦凝聚体的一维动力学自旋轨道耦合（SOC）。通过拉曼跃迁向原子传递与自旋相关的动量脉冲，产生了 SOC。这些脉冲是由经典泵浦场与量子动力学腔场协同作用产生的。当泵浦功率超过临界值时，拉曼耦合表现为原子以超辐射的方式将光子填充到腔模中。同时，这些光子对原子产生反作用，迫使它们对自旋-空间状态进行排序。这种 SOC 诱导的超辐射 Dicke 相变导致了自旋螺旋极化子凝聚体的形成。我们通过原子动量的自旋分辨成像和腔场发射的时间外差测量来观察到 SOC 的出现。在量子气体腔 QED 中的动力学 SOC，以及对动力学规范场的扩展，可能会在耦合光物质系统中产生类似迈斯纳效应、拓扑超流和奇异量子霍尔态。
