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Public Seminar of PhD Candidate: Entanglement Entropy at Quantum Phase Transitions: From Wilson Fisher to Deconfined Quantum Critical Points

Speaker

Mr. Menghan SONG

Affiliation The University of Hong Kong
Date July 21, 2026 (Tuesday)
Time 11:30 a.m.
Venue Room 518A, 5/F, Chong Yuet Ming Physics Building, The University of Hong Kong

Abstract

This research explores the finite size scaling behavior of Rényi entanglement entropy (EE) in various two-dimensional quantum many-body systems, focusing on the nature of quantum phase transitions, particularly the deconfined quantum critical point (DQCP). We systematically analyze the sub-leading corrections to the EE, employing the “subtracted EE” method to isolate contributions beyond the leading perimeter law. Our findings reveal that for a spin-1/2 model on a square lattice with Néel order, the logarithmic correction coefficient aligns with theoretical predictions based on Goldstone modes. Additionally, we investigate the (2+1)d O(3) Wilson Fisher QCP, where we observe logarithmic corrections at sharp corners but not for smooth boundaries. In the context of DQCP, specifically the square-lattice SU(N) models, we demonstrate that anomalous logarithmic behavior persists for N below a critical threshold, indicating that these transitions do not conform to expected fixed points. For N above this threshold (between 7 and 8), the DQCPs align with conformal fixed points, describable by Abelian Higgs field theories. Our study contributes to the ongoing discourse on DQCPs, highlighting their complex nature and implications for future theoretical and experimental investigations.

 

Anyone interested is welcome to attend.