Atoms gain momentum as they emit light, creating hybrid entanglement

Four-level atoms within a specially designed cross-cavity system are now achieving steady-state superradiance without relying on traditional, high-quality cavity conditions. Jarrod T. Reilly of JILA and the University of Colorado, along with colleagues, demonstrate this phenomenon using collective dissipative dynamics, a method where atoms synchronize light emission. The resulting superradiant states exhibit unusual super-Poissonian photon statistics, necessitating a complex description beyond standard physics. Because superradiant decay imparts a momentum impulse to the atoms, the system generates substantial hybrid entanglement linking the atoms’ spin and their motion, with potential for improved acceleration sensing. Steady-state superradiance, achieved in a novel cross-cavity system, now occurs without reliance on traditional high-finesse, or “good,” cavity conditions. This system symmetrically couples four-level atoms using transitions between electronic and motional states along perpendicular axes, establishing a new pathway…