Susanne Butz, Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany.
Title: A Tunable Josephson Metamaterial
Abstract: We present experimental data on a tunable magnetic metamaterial consisting of rf-SQUIDs. A metamaterial is a medium constructed of artifical elements, so- called meta-atoms, that interact in a specific way with an incoming electromagnetic wave. The size of and the distance between the individual meta-atoms is much smaller than the wavelength. Our metamaterial consists of one-dimensional arrays of 27 rf-SQUIDs, one chain placed inside each of the gaps of a coplanar waveguide. Due to the nonlinear inductance of the rf-SQUID, its resonance frequency is tunable in situ by applying a dc magnetic field. We demonstrate that this results in tunable effective parameters of our metamaterial. In order to obtain the effective magnetic permeability from the measured data, we employ a technique that uses only the complex transmission coefficient S21.
Title: Spins and photons: toward quantum networks in diamond
Abstract: Long-lived electronic and nuclear spin states have made nitrogen-vacancy (NV) defects in diamond a leading candidate for solid-state quantum information processing. Moreover, their coherent optical transitions open opportunities for quantum communication. This talk will consider the motivation and requirements for optically-networked quantum devices, and explore challenges and opportunities for realizing them in diamond. In particular, the resonant excitation and emission in these defect centers enables single shot spin detection as well as observation of two-photon quantum interference; these two capabilities have enabled measurement-based entanglement between remote NV centers.