Dr. Britton Plourde , Syracuse University
Tuesday, November 27, 2018 - 4:00pm
Allen 321

Superconducting metamaterials formed from arrays of thin-film lumped circuit elements provide a route for implementing novel dispersion relations and band structure in a circuit QED environment. We have implemented metamaterial resonators from left-handed transmission lines and characterized their dense spectrum of modes through a combination of microwave transmission measurements and laser scanning microscopy imaging of the standing-wave structure on the various resonances. By appending a segment of a conventional transmission line on one end of our metamaterial, we have coupled a flux-tunable transmon qubit to the structure and observed the interaction of the qubit with the metamaterial by tuning its transition frequency through resonance with each of the modes. Through time-domain qubit measurements at different flux bias points, we are able to explore the variation in the qubit relaxation time as a function of frequency, with significant dips in lifetime as the qubit transition approaches each mode and a recovery of the lifetime in between resonances. In addition, we have measured the Stark shift of the qubit transition as we drive the metamaterial with different powers on each of its resonances that are coupled to the qubit.

Reciprocal and nonreciprocal amplification at the quantum level
Preserving the quantum coherence of signals is of paramount importance for components utilized in quantum information processing, quantum computation and quantum measurement setups. In recent years a tremendous progress has been made in the development of quantum-limited components, such as reciprocal and nonreciprocal amplifiers, circulators and isolators. A promising way to design these devices is based on parametric modulation of coupled modes, where the required mode-mixing processes are realized by utilizing Josphson junction-based tunable couplers ...
Talk location: 321 Allen Hall Fall 2018 Seminar
Dr. Anja Metelmann
Freie Universität Berlin, Germany
Thermal Equilibrium vs. The Real World
Most of our understanding of the properties of materials comes from the study of thermal equilibrium, which is the state reached if one leaves a system undisturbed for long enough. But for many disordered materials, “long enough” is often years or even centuries. This talk will discuss how insights from the study of nonlinear dynamics, the field to which John David Crawford made many important contributions, have enabled us to understand some striking phenomena that ...
Talk location: 11 Thaw Hall Seminar Fall 2018
Dr. Susan Coppersmith
Nonlinear Dynamics and Quantum Computers
John David Crawford was an expert in dynamical systems and bifurcation theory, which is the study of systems that are subject to strong driving. This talk will discuss why this area of research is important for quantum computation. In particular, it will be shown how concepts from nonlinear dynamics proved to be critical in the development and improvement of qubits, the fundamental building blocks of quantum computers, using quantum dots in silicon/silicon-germanium heterostructures.
Talk location: 321 Allen Hall Seminar Fall 2018
Dr. Susan Coppersmith
Dr. Christopher Hendon (University of Oregon)
Title and Abstract TBD
Talk location: Thaw 11 Spring 2019 Seminar
Christopher Hendon
University of Oregon
Dr. Nai Phuan Ong (Princeton University)
Talk location: Doherty Hall A301D Spring 2019 Seminar
Dr. Nai Phuan Ong
Princeton University
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