Base-Independent Photon Entanglement in Superradiance of Multilevel Atoms

We propose realization of sources of multiphoton entanglement from atomic ensembles via a fast and deterministic superradiance process [1]. We leverage the collective emission phenomenon of superradiance in order to generate multiphoton states, and entangle them in their frequency degree of freedom by incorporating the dynamics of multilevel atoms. Such deterministic high-yield sources of entangled photons are crucial for applications pertaining to quantum computation, quantum communications and quantum metrology [2]. We emphasize that the original Dicke superradiance model [3] and its extensions have only dealt with the atomic-ensemble entanglement and photonic ensemble-average observables such as intensity and autocorrelation, and photonic entanglement in superradiance has never been considered.