时间：5月15日 19：00

地点：物质楼A309会议室

题目: Fracton Self-Statistics
报告人:宋昊 中科院理论物理研究所

Abstract:
Fracton order was theoretically discovered during the search for better quantum memories and has become an active frontier of quantum physics, attracting great interest from the perspectives of condensed matter, quantum information, and quantum field theory. It describes novel quantum phases of matter that host quasiparticles with restricted mobility, and thus lies beyond the existing paradigm of topological order. In particular, excitations that cannot move without creating multiple excitations are called fractons. In this talk, I will first briefly review the history and some exactly solvable toy models of fracton physics. Then I will present our recent work (arXiv:2304.00028) on a fundamental open question -- can the notion of self-exchange statistics be naturally defined for fractons, given their complete immobility as isolated excitations? Surprisingly, we demonstrate how fractons can be exchanged, and show that their self-statistics is a key part of the characterization of fracton orders. We derive general constraints satisfied by the fracton self-statistics in a large class of Abelian fracton orders. Explicitly, we show the existence of semionic or fermionic fracton self-statistics in some twisted variants of the checkerboard model and Haah's code, establishing that these models are in distinct quantum phases as compared to their untwisted cousins.

个人简介: 
宋昊，中国科学院理论物理研究所副研究员。2009年本科毕业于南京大学，2015年获得美国科罗拉多大学博尔德分校物理学博士学位，之后先后在西班牙马德里大学和加拿大麦克马斯特大学从事博士后研究，2022年入职中科院理论物理所。研究方向为量子多体理论，聚焦于新奇量子物态（特别是topological phases和fracton phases）的基础研究以及其在量子技术中的潜在应用。代表性工作包括：建立一般量子多体系统中晶格对称性保护拓扑态的基本物理图像，构造了twisted和cage-net两类严格可解的fracton模型，发现和刻画了非阿贝尔fracton态，确定了fracton纠错码的理论容错极限。