Condensed Matter Seminars

Microwave signals have appeared during the last decade as a powerful and versatile platform to investigate a wide variety of quantum phenomena, from fundamental quantum optics to more oriented researches toward quantum information processing. This specific place originates from the fact that microwave signals can on one hand be precisely tailored and controlled with standard commercial electronics. On the other hand they can easily be processed at the single photon level in the quantum regime by superconducting circuits cooled down to dilution fridge temperatures thanks to a unique component, the Josephson junction, an intrinsic non dissipative lumped non-linear inductor.

I will present how we designed and built a superconducting circuit, based on a Josephson ring modulator (JRM), a ring of 4 Josephson junctions in a Wheatstone bridge configuration, allowing non-degenerate three wave-mixing. I will show that, when pumped at the appropriate frequency, this single circuit behaves as a tunable beam splitter with frequency conversion, a quantum limited amplifier or an EPR states generator. Using frequency conversion, we demonstrate on demand capture, storage and release of microwave radiations with approx. 80% catching efficiency and about 30 storage operations per memory lifetime. We then demonstrate entanglement generation between a propagating microwave mode and a localized mode in the cavity.