Northup, Tracy

Date: Tuesday October 21, 2014
Time: 15:00
Place: ETH Zurich, Hönggerberg, HPF G 6
Hosts: Jonathan Home

Entanglement as a resource for a cavity-based quantum interface

Tracy Northup
Universität Innsbruck, Austria

Entanglement can enhance the coherent interaction of light and matter at a quantum interface, enabling information transfer within future quantum networks.  Here, our interface consists of calcium ions trapped within an optical cavity.  First, I will describe how we transfer a quantum bit of information from a single ion onto a photon. Next, we replace the ion by two ions in a maximally entangled state, in which a logical quantum bit is encoded.  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.  The latter case corresponds to a superradiant state of the ion-cavity system, for which we demonstrate that quantum information transfer onto a single photon is improved.  By constructing an interface based on collective effects, one can thus relax the technical requirements for the faithful mapping of quantum information.