Condensed Matter Theory Seminar - Yuzho Tian - Purdue University

Signatures of localization on the edge of a fractional topological insulator Recent experiments in van der Waals moiré materials have reported realizations of two-dimensional fractional topological insulators (FTIs). While the bulk filling is fixed by experiment, the structure of the edge is not, and edge transport offers one of the few experimentally accessible handles on it. In this talk I will discuss the edges of FTIs at filling factors \nu = 2(1 ± 1/n) with integer n ≥ 2 (even or odd), each of which supports four counter-propagating edge modes. The edge modes can undergo partial localization, leaving two of the four conducting. I will show that this happens through three distinct channels. For each channel I construct the reduced theory of the surviving modes, extract the minimal quasiparticle charge, and compute the two-terminal conductance. The conductance alone does not distinguish the three phases, but combined with the minimal quasiparticle charge it gives a fingerprint that identifies them uniquely. Biography: Yuzhuo Tian is a PhD candidate in physics at Purdue University, working with Professor Jukka Väyrynen in condensed matter theory. Her research focuses on topological phases of matter and their edge transport properties. Her recent work concerns the edge theories of fractional topological insulators. She received her bachelor's degree in physics from Zhejiang University in Hangzhou, China, in 2022 and continued graduate study there before joining Purdue in 2024, where she received her master's degree in 2026. Host: Meng Cheng