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The Anthony J Leggett Institute for Condensed Matter Physics Seminar: Models of Deconfined Criticality for Square and Triangular Lattice Antiferromagnets

Event Type
Seminar/Symposium
Sponsor
Physics Department
Location
ESB 3110
Date
Nov 29, 2023   11:00 am - 12:00 pm  
Speaker
Henry Shackleton, Harvard University
Contact
Ljubica Milutinovic
E-Mail
ljubicam@illinois.edu
Phone
217-300-6393
Views
69
Originating Calendar
Physics - Institute for Condensed Matter Theory Seminar

Deconfined quantum critical points (DQCP) emerge at continuous phase transitions between distinct ordered phases, where conventional Landau-Ginzburg formulations of the critical theory fail and the resulting description can involve emergent gauge fields. In the first part of my talk, I will propose a unified theory for describing a pair of continuous phase transitions numerically observed in the frustrated square lattice Heisenberg antiferromagnet, where a spin liquid phase appears to emerge in between Neel and valence bond solid (VBS) phases. The proposed DQCPs exhibit a plethora of unconventional phenomena, including anisotropic fixed points and dangerously irrelevant perturbations. In the second part of my talk, I will describe recent work analyzing an effective model of triangular lattice antiferromagnetism which supports coplanar magnetic order as well as VBS and spin liquid phases. We show that this effective model is sign-problem-free and amenable to large-scale Monte Carlo simulations, which reveal a direct transition between magnetic and VBS phases.
 

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