San José State University, Department of Physics & Astronomy
Abstract: Superposition and entanglement are essential quantum properties which can be easily destroyed, rendering quantum devices useless. New modes of harnessing system-environment coupling can instead enable robust, entangled quantum phases and provide a route toward scalable quantum technologies. Weak measurement is one such route, which enables the extraction of targeted information from a quantum system while minimizing decoherence due to measurement backaction. However, in many-body quantum systems, backaction from weak measurements can have novel effects on wavefunction collapse. In this talk I will discuss a formalism we developed to describe weakly measured many-body quantum systems. I will describe a theoretical study of non-interacting fermions in one dimension. Repeated measurement of on-site occupation number drives the fermionic system from the completely delocalized Fermi sea toward a Fock state with well defined atom number on each site. We find that the spatial measurement resolution strongly affects both the collapse dynamics and the final state. We compare small-system exact numerical results to an analytical model and find that the quantum state undergoing measurement is described by a modified diffusion equation. These results indicate that weak measurement may be a powerful tool for state engineering in many-body quantum systems.
Biography: Dr. Hilary Hurst is an Assistant Professor in the Department of Physics & Astronomy at San Jose State University. She is a quantum educator and theoretical physics researcher, with broad interests in condensed matter theory and many-body atomic physics. Her research primarily focuses on the theory of quantum noise and quantum measurement and feedback control. In addition to research, Dr. Hurst is passionate about making quantum physics education more accessible and preparing students to work in the growing quantum technology industry. Dr. Hurst is originally from Greeley, Colorado and received her BS in Engineering Physics from the Colorado School of Mines in 2012. While at Mines she was a recipient of the President’s Senior Scholar-Athlete award. She went on to earn a Masters in Applied Mathematics & Theoretical Physics at the University of Cambridge (UK), and received her PhD in theoretical condensed matter physics from the Joint Quantum Institute at the University of Maryland. Following her doctoral work, she was a National Research Council (NRC) Postdoctoral Fellow at NIST in the Quantum Measurement Division. Dr. Hurst joined the faculty of San Jose State University in Fall 2020.
All lectures held in CoorsTek 140 unless otherwise noted