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We report the implementation of a Duan-Lukin-Cirac-Zoller (DLCZ) protocol heralded single-photon source using an ensemble of cold rubidium simultaneously coupled to two optical cavities, enabling substantial enhancements in photon generation rates.

We report the development of a quantum gate consisting of a rubidium atomic ensemble coupled to double cavity QED, its characterization using double quantum process tomography, and its potential use in a butterfly quantum network.

We investigate the charging dynamics in epitaxially grown InAs quantum dots under resonant excitation with and without additional low-power above-band excitation. Time-resolved resonance fluorescence from a charged exciton (trion) transition is recorded as the above-band excitation is modulated on and off. The fluorescence intensity varies as the QD changes from charged to neutral and back due to the influence of the above-band excitation. We fit the transients of the time-resolved resonance fluorescence with models that represent the charging and neutralization processes. The time dependence of the transients indicate that Auger recombination of resonantly excited trions is largely responsible for neutralization of the charged state when the above-band excitation is off. The addition of above-band excitation revives the resonance fluorescence signal from the trion transition. We conclude that the above-band laser excites charges that relax into the bound state of the quantum dot via two different charge transport processes. The captured charges return the QD to its initial charge state and allow resonant excitation of the trion transition. The time dependence of one charge transport process is consistent with ballistic transport of charge carriers excited non-local to the QD via above-band excitation. We attribute the second charge transport process to carrier migration through a stochastic collection of weakly-binding sites, resulting in sub-diffusion-like dynamics.arXiv:1812.07672v1 [cond-mat.mes-hall]

Entanglement-on-demand networks hold tremendous promise, but need heralding and storing. We report progress towards building a quantum processor using a cold rubidium ensemble in double cavity-QED system which helps herald single-photons.