Collective coupling between two ions and a cavity for an enhanced quantum interface
Bernardo Casabone, Konstantin Friebe, R. Blatt, Tracy E. Northup · arXiv (Cornell University) · 2014
We prepare a maximally entangled state of two ions and couple both ions to the mode of an optical cavity. The phase of the entangled state determines the collective interaction of the ions with the cavity mode, that is, whether the emission of a single photon into the cavity is suppressed or enhanced. By adjusting this phase, we tune the ion–cavity system from subto superradiance. We then encode a single qubit in the two-ion superradiant state and show that this encoding enhances the transfer of quantum information onto a photon. These results constitute a proof of principle that cooperative effects can improve the performance of a quantum interface.