Josephson Junction Arrays in Circuit QED Architecture

QuICS Special Seminar

Cosmic Raj (University of Tokyo, Nakamura group)
March 8, 2017
CSS 3100A

Understanding and engineering of quantum many-body systems is a big challenge in quantum physics and quantum information processing. Studies in artificial quantum many-body systems with well-controlled parameters should play a central role for that purpose. One of the promising platforms for realizing an artificial quantum many-body system is a Josephson junction array (JJA). It consists of an array of superconducting islands connected by small Josephson junctions, where various kinds of classical and quantum Hamiltonians (such as Bose-Hubbard, XY Hamiltonians) can be implemented depending on parameters of the system. Here, we will present our recent progress of experimental study of JJAs using the circuit quantum electrodynamics (cQED) architecture. In contrast to the conventional transport measurements in JJAs, the cQED approach has some advantages: The system is weakly perturbed by the microwave excitation and properties of not only ground state but excited states are investigated at single photon level. In this talk, we particularly focus on our investigations of JJA in a magnetic field, and present some preliminary results of vortex lattice melting process.

Cosmic will be visiting UMD Wed-Fri. Please contact Jake Taylor if you’d like to meet with him during his trip.