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TT: Fachverband Tiefe Temperaturen
TT 43: Correlated Electrons: Other Theoretical Topics
TT 43.8: Vortrag
Donnerstag, 20. März 2025, 11:30–11:45, H33
Deconfinement Phase Transitions in a nematic two dimensional XY model with Long-range couplings — •Luis Walther1, Josef Willsher1,2, and Johannes Knolle1,2,3 — 1Technical University of Munich, TUM School of Natural Sciences, Physics Department, 85748 Garching, Germany — 2Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, 80799 Munchen, Germany — 3Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
The Modified XY model is an illustrative example of the interplay between ferromagnetic and nematic couplings, hosting both vortex and half-vortex excitations. The model gives rise to an exotic second order phase transition driven by the deconfinement of vortices into half-vortices. This transition is in the universality class of the Ising model, displaying features of the ’Deconfined Criticality’ scenario. We analyse the effect of long-range algebraically decaying couplings ∼ r−2−σ on the model. Long-range couplings enrichen the phase diagram and influence the deconfinement phase transition. We find that the transition persists for long-range couplings decaying fast enough so that σ>2−η holds, where η is the the correlation function exponent of the short-range XY model. Our results are based on Landau Peierls type arguments as well as Renormalisation Group flow techniques. Long-range couplings appear in many experimental setups including 2D Rydberg simulators. Therefore we hope our work contributes to enable the experimental observation of the deconfinement phase transition present in the model.
Keywords: Deconfinement Phase Transition; Topological Phase Transition; Long-range couplings