@article {1907, title = {Steady-state superradiance with Rydberg polaritons}, journal = {arXiv:1611.00797}, year = {2016}, month = {2016/11/02}, abstract = {

A steady-state superradiant laser can be used to generate ultranarrow-linewidth light, and thus has important applications in the fields of quantum information and precision metrology. However, the light produced by such a laser is still essentially classical. Here, we show that the introduction of a Rydberg medium into a cavity containing atoms with a narrow optical transition can lead to the steady-state superradiant emission of ultranarrow-linewidth\ nonclassical\ light. The cavity nonlinearity induced by the Rydberg medium strongly modifies the superradiance threshold, and leads to a Mollow triplet in the cavity output spectrum\−this behavior can be understood as an unusual analogue of resonance fluorescence. The cavity output spectrum has an extremely sharp central peak, with a linewidth that can be far narrower than that of a classical superradiant laser. This unprecedented spectral sharpness, together with the nonclassical nature of the light, could lead to new applications in which spectrally pure\ quantum\ light is desired.

}, url = {https://arxiv.org/abs/1611.00797}, author = {Zhe-Xuan Gong and Minghui Xu and Michael Foss-Feig and James K. Thompson and Ana Maria Rey and Murray Holland and Alexey V. Gorshkov} } @article {1470, title = {Steady-state many-body entanglement of hot reactive fermions}, journal = {Physical Review Letters}, volume = {109}, year = {2012}, month = {2012/12/4}, abstract = { Entanglement is typically created via systematic intervention in the time evolution of an initially unentangled state, which can be achieved by coherent control, carefully tailored non-demolition measurements, or dissipation in the presence of properly engineered reservoirs. In this paper we show that two-component Fermi gases at ~\mu K temperatures naturally evolve, in the presence of reactive two-body collisions, into states with highly entangled (Dicke-type) spin wavefunctions. The entanglement is a steady-state property that emerges---without any intervention---from uncorrelated initial states, and could be used to improve the accuracy of spectroscopy in experiments with fermionic alkaline earth atoms or fermionic groundstate molecules. }, doi = {10.1103/PhysRevLett.109.230501}, url = {http://arxiv.org/abs/1207.4741v1}, author = {Michael Foss-Feig and Andrew J. Daley and James K. Thompson and Ana Maria Rey} }