Abstract: Through sub-wavelength structuring of materials, classical metamaterials have shown exquisite control over electromagnetic properties, experimentally demonstrating phenomena not found in nature such as a negative index of refraction. Superconducting circuits, one of the leading platforms for quantum information science, are a strong candidate to extend this control over electromagnetic properties to quantum coherent systems, due to their high nonlinearity, low loss, and relatively simple fabrication. In this seminar, we will detail how initial steps along this path of applying photonic engineering techniques to superconducting circuits have advanced microwave quantum optics and quantum measurement. The Josephson traveling-wave parametric amplifier, a nonlinear transmission line with a metamaterial phase matching scheme, has a bandwidth of several GHz, high dynamic range, and near quantum limited noise performance. This amplifier has sufficient bandwidth and dynamic range for simultaneous multiplexed high fidelity readout of tens to hundreds of qubits and provides new microwave quantum optics capabilities such as broadband squeezed light generation. We will then discuss development of a multi-qubit quantum processor with average coherence exceeding that of comparable multi-qubit chips from large commercial labs. We propose several future directions of quantum phononic metasurfaces, ultrafast coherent control schemes for transmon qubits, and microwave quantum optics in traveling wave devices.
Bio: In 2016, Kevin received a PhD in physics titled "Nonlinear Light-Matter Interactions in Metamaterials" from Xiang Zhang's group at the University of California at Berkeley. He then joined the Quantum Nanoelectronics Lab (Siddiqi group) at UC Berkeley as a postdoctoral researcher to lead development of multi-qubit quantum processors.
Host: Marc Baldo