Dresden 2026 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 2: Focus Session: New Routes to Localization and Quantum Non-Ergodicity I (joint session TT/DY)
DY 2.4: Topical Talk
Monday, March 9, 2026, 11:15–11:45, HSZ/0003
Interference, topology, and new Hilbert-space routes to quantum non-ergodicity — •Yi-Ping Huang1,2,3 and Tao-Lin Tan1 — 1Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan — 2Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan — 3Institute of Physics, Academia Sinica, Taipei 115, Taiwan
A central challenge in nonequilibrium quantum physics is to understand why certain many-body systems fail to thermalize even in the absence of disorder or integrability. In this talk, I will outline a different perspective in which non-ergodicity is governed by hidden geometric structures in Hilbert space rather than by conventional real-space mechanisms. This viewpoint leads to the concept of interference-caged quantum many-body scars (ICQMBS), where exact many-body destructive interference confines eigenstates to small regions of the Fock-space graph. Remarkably, interference zeros and graph automorphisms emerge as universal organizing principles, revealing a class of topological ICQMBS whose robustness originates from local Fock-space topology rather than symmetries or constraints. This framework not only explains diverse non-ergodic phenomena from one-dimensional systems to two-dimensional gauge models but also provides new tools for systematically identifying them. I will end with a brief look at stabilizing QMBS through the lens of Kramers-Wannier duality, illustrating the challenges and possibilities that arise when studying QMBS under duality.
Keywords: Quantum many-body scars; Duality; Flat bands; Lattice gauge theories; Non-equilibrium quantum dynamics