When
Where
Title
Bridging the connectivity gap with photons in waveguides
Abstract
High connectivity between qubits underpins non-local gates, long-range interacting phases of matter, and distributed quantum networks, yet many scalable platforms are limited to nearest-neighbor coupling. Photons in waveguides offer a route around this limit across both microwave and optical domains, and in this talk I will present two such efforts.
In the first part, I will discuss a scalable superconducting-qubit simulator in which long-range interactions are mediated by a quantum bus built from a microwave photonic bandgap metamaterial. We realize a 10-qubit simulator of the 1D Bose-Hubbard model with in-situ tunable hopping range, and observe a crossover from integrable to ergodic many-body dynamics as the range is tuned.
In the second part, I will turn to connecting quantum emitters with optical photons using an integrated silicon photonics platform based on T centers—carbon-hydrogen defects with long spin coherence times—in the telecom O-band. With photonic crystal cavity arrays coupled to a bus waveguide, we achieve wavelength-multiplexed emission and identify laser-induced spectral diffusion as the dominant broadening mechanism. We further demonstrate coherent control and optical readout of a T center electron spin and create long-lived entanglement in a three-spin register including a nearby silicon-29 nucleus—first steps toward a scalable quantum network in silicon.
Bio
Xueyue (Sherry) Zhang is an Assistant Professor of Applied Physics at Columbia University. She earned her B.Eng. from Tsinghua University and her Ph.D. in Applied Physics from Caltech, followed by a Postdoc training at UC Berkeley. Dr. Zhang's research interests include superconducting circuits, quantum many-body simulations, and color centers in silicon. Her work has earned her several awards, including the Miller Postdoc Fellowship, the Boeing Quantum Creator Prize, and the Rising Star in Physics.