SEMINAR 2025
Characterizing quantum phases of matter on quantum simulators: from mixed-state phases to machine learning
| Speaker | Yijian Zou, Perimeter Institute for Theoretical Physics, Canada |
| Date/Time | Tuesday, 26 Aug, 12nn |
| Location | S11-02-07 Conference Room |
| Host | Prof Gong Jiangbin |
Abstract
Recent advances have revealed nontrivial quantum phases in open quantum systems. In this talk, I will present a unified perspective on mixed-state quantum phases, based on my recent work spanning theoretical frameworks, numerical simulations, and experimental signatures on noisy quantum devices. These results demonstrate the existence of novel mixed-state phases and highlight their deep connections to quantum error correction.
In a complementary direction, I will discuss ongoing work on machine learning approaches to quantum phases of matter. In particular, I will introduce a data-driven framework for universal phase classification from classical shadows, focusing on pure-state phases connected by finite-depth circuits. I will also outline theoretical results identifying fundamental barriers to learning certain phases—such as symmetry-breaking ones—emphasizing the tension between expressibility and learnability in many-body systems.
Together, these results aim to advance a more complete understanding of quantum phases in the NISQ era, bridging theory, numerics, and experiment.
Biography
Dr. Yijian Zou is a postdoctoral fellow at Perimeter Institute for Theoretical Physics. He received his Ph.D. in Physics from the University of Waterloo and has held research positions at Stanford University as a Q-FARM Postdoctoral Fellow and at Google X as a Research Intern.
His research lies at the intersection of quantum information and quantum many-body physics, with a focus on entanglement-based characterization, numerical simulation, and the experimental realization of quantum phases of matter. His recent work explores the definition, detection, and classification of mixed-state quantum phases, as well as their connections to quantum error correction and machine learning.
Dr. Zou has published 26 papers, including 11 in Physical Review Letters, Physical Review X, SciPost Physics, and Nature Communications (under review). His work bridges theory, numerics, and experiment, aiming to build a unified framework for understanding many-body quantum phenomena in quantum simulators.