Ultranarrow-linewidth atoms coupled to a lossy optical cavity mode
synchronize, i.e. develop correlations, and exhibit steady-state
superradiance when continuously repumped. Such a superradiant laser
displays rich collective physics and promises metrological applications
as an ultrastable frequency reference. These features inspire us to
investigate if analogous spin synchronization is possible in a different
platform that is one of the most robust and controllable experimental
testbeds currently available: ion-trap systems.
In this talk, I will introduce the steady-state superradiant laser as the alter ego of the traditional laser, where the role of the atoms and the cavity mode are interchanged. I will highlight the role of synchronization in drastically reducing the linewidth of the output light. I will then proceed to describe my recent theoretical work on synchronizing an ensemble of trapped ions using a collective vibrational mode as a substitute for an optical cavity mode, and observing their collective behavior through Ramsey interferometry.