Embracing Macroscopic Quantum Phenomena: From Emergent Material Phases to Quantum Computing Devices

Abstract:
Macroscopic quantum phenomena extend quantum behavior beyond the atomic scale, leading to complex effects with significant implications for energy-efficient technologies and quantum computing. Understanding these phenomena experimentally requires both ideal material platforms that host them and advanced measurement techniques that can access their quantum degrees of freedom. The first part of my presentation focuses on correlated electronic phenomena in rhombohedral graphene multilayers, demonstrating their potential as a powerful platform for studying macroscopic quantum phenomena. The second part of the talk shifts focus to superconducting quantum circuits and their interaction with mechanical systems. I will present the observation of interface piezoelectricity in aluminum–silicon junctions, which is an unexpected decoherence channel in superconducting qubits. Finally, I will discuss the potential of superconducting quantum circuits and nanomechanical systems as novel tools for characterizing complex macroscopic quantum phenomena in condensed matters.

Bio:
Haoxin Zhou is a postdoctoral researcher in the Quantum Devices Group at UC Berkeley, working with Prof. Alp Sipahigil. His research focuses on superconducting microwave circuits and nanomechanical devices. Haoxin earned his Ph.D. in Physics from the University of California, Santa Barbara, in 2021, where he worked with Prof. Andrea Young on graphene van der Waals heterostructures. He completed his B.S. in Physics at the University of Science and Technology of China in 2015.