Xueyue (Sherry) Zhang is an Assistant Professor in the Department of Applied Physics and Applied Mathematics at Columbia University starting January 2025. She earned her B.Eng. with honors in Microelectronics Engineering from Tsinghua University in 2017 and Ph.D. in Applied Physics from Caltech in 2023 supervised by Dr. Oskar Painter. Dr. Zhang then joined UC Berkeley as a Miller Postdoctoral Fellow, working with Dr. Alp Sipahigil in EECS and Physics.
Haoxin Zhou is a postdoctoral researcher working with Alp Sipahigil in the Quantum Devices Group in UC Berkeley. His research focuses on superconducting microwave circuits and nanomechanical devices. Prior joining UC Berkeley, he worked as an IQIM Postdoctral Scholar at the California Insitute of Technology. He obtained his PhD in Physics from the University of California, Santa Barbara in 2021 and B.S. from the University of Science and Technology of China in 2015.
Silicon, a mature platform for the semiconductor industry, has become a leading platform for future quantum technologies. As a high-purity material, it serves as a low-noise host for a variety of quantum defects. As a low-loss material, it is a desirable substrate and material platform for next generation quantum devices. However, the lack of piezoelectricity in silicon, due to its centro-symmetric structure, poses challenges for its electromechanical applications. For example, one common approach to realize electromechanics in silicon relies on hybrid integration with a different...
Ultralong lifetimes of silicon nanomechanical resonators at cryogenic temperatures and microwave frequencies make them promising resources in quantum engineering. In this work, we propose a nanomechanical qubit achieving strong single-phonon level anharmonicity of 5 MHz without the need for coupling to an ancillary qubit of a hybrid quantum architecture. This qubit design combines a nano-machined silicon cantilever brought in proximity to a silicon surface using microelectromechanical actuators. The surface forces between the cantilever and the silicon surface provide an effective...
Superconducting quantum circuits are leading candidates for quantum computing. Scaling up these systems for practical applications will require compact coherent qubits that store the quantum states, high fidelity quantum gates that process them, and a scalable architecture that can accommodate complex error correction circuits. Meeting such requirements is mainly impeded by the unavoidable presence of two-level systems (TLS), which act as a decoherence source that results in the loss of quantum information via phonon emission. In this project, we engineer superconducting circuits...
Yu-Lung Tang is a Physics PhD student at the University of California, Berkeley. He started working with Alp Sipahigil in the Quantum Devices Group in July 2022 on the characterization of Silicon color center in integrated photonics.
The overhead to construct a logical qubit from physical qubits rapidly increases with the de- coherence rate. Current superconducting qubits reduce dissipation due to two-level systems (TLSs) by using large device footprints. However, this approach provides partial protection, and results in a trade-off between qubit footprint and dissipation. This work introduces a new platform using phononics to engineer superconducting qubit-TLS interactions. We realize a superconducting qubit on a phononic bandgap metamaterial that suppresses TLS- mediated phonon emission. We use the qubit to probe its...
