Rotational superradiance in a time-reversal symmetry-broken quantum gas inside an optical cavity

The appearance of quantized vortices in a superfluid and a Bose-Einstein condensate (BEC) stems from their nontrivial response to time-reversal symmetry (TRS). Here, we show that breaking of the TRS by, for example, rotation or an external synthetic magnetic field in a transversely driven BEC coupled to a single mode of an optical cavity modifies drastically Dicke superradiance and self-ordering phenomena in this system. In particular, photon scattering from the pump laser into the cavity is amplified by rotational motion of the BEC, leading to so-called “rotational superradiance”—in a loose analogy to black-hole physics—with distinct critical scaling properties. In turn, cavity photons mediate long-range, periodic attractive interactions among the vortices, which compete with pairwise logarithmic repulsive vortex interactions and deform the Abrikosov triangular vortex lattice favoring a stripe-like pattern. Remarkably, the rotation of the BEC and the topological properties of the vortex lattice can be monitored nondestructively through the cavity output field.