The order parameter of a quantum-coherent many-body system can include a phase degree of freedom, which, in the presence of an electromagnetic field, depends on the choice of gauge. Because of the relationship between the phase gradient and the velocity, …

Gauge matters: observing the vortex-nucleation transition in a Bose condensate Read more »

Spin-orbit coupling is an essential ingredient in topological materials, conventional and quantum-gas-based alike. Engineered spin-orbit coupling in ultracold-atom systems—unique in their experimental control and measurement opportunities—provides a major opportunity to investigate and understand topological phenomena. Here we experimentally demonstrate and …

Tunable Spin-Orbit Coupling via Strong Driving in Ultracold-Atom Systems Read more »

We theoretically explore atomic Bose–Einstein condensates (BECs) subject to position-dependent spin–orbit coupling (SOC). This SOC can be produced by cyclically laser coupling four internal atomic ground (or metastable) states in an environment where the detuning from resonance depends on position. …

Position-dependent spin–orbit coupling for ultracold atoms Read more »

Nathan Goldman et al‘s result describing techniques for measuring topology in a laser-coupled honeycomb lattice has been featured as a “Highlight of 2013” by The New Journal of Physics! This rocks! Highlights page: http://iopscience.iop.org/1367-2630/page/highlights-of-2013 Article: http://iopscience.iop.org/1367-2630/15/1/013025/article