Q-FARM presents "Many-body invariants from statistical correlations of randomized measurements"

Many-body invariants from statistical correlations of randomized measurements
Wednesday, June 17, 2020 - 12:00pm
Zoom ID: 987 676 025
Mohammad Hafezi (University of Maryland)
Abstract / Description: 

With the advances of quantum simulators in implementing various quantum many-body states, it is important to find efficient ways to characterize and measure many-body states, without resorting to full quantum state tomography. Specifically, in contrast to electronic materials, where the measurements are mainly within the linear-response paradigm, quantum simulators offer unique access to the full wave function that inspires novel probing approaches. In this talk, I discuss how various quantities, such as entanglement spectrum, symmetry-protected topological invariants, and fractional many-body Chern number could be extracted. In the latter case, we show how such an invariant can be measured, using a single wave function, without the knowledge of the Hamiltonian. This should be contrasted to the conventional way, where on requires a family of many-body wave functions parameterized by twist angles in order to calculate the Berry curvature.

Science Advance 6, 3666 (2020)
arxiv 2005.13543
arxiv 2005.13677


Mohammad Hafezi is an Associate Professor with a joint appointment in the Physics and Electrical and Computer Engineering Departments, at the University of Maryland, and a fellow of the Joint Quantum Institute. He completed his undergraduate degree in École Polytechnique and received his Ph.D. in Physics from Harvard University in 2009. His research interest includes quantum optics, topological physics, condensed-matter, and quantum information sciences. He has had a number of foundational contributions in exploring quantum many-body and topological physics in synthetic systems such as photonic and atomic platforms, including the first proposal and realization of topological edge states for optical photons. He is the recipient of the Sloan Fellowship, the Young Investigator Award of the US Naval Research Office.