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TT: Fachverband Tiefe Temperaturen
TT 40: Focus Session: Recent Progresses in Criticality in the Presence of Boundaries and Defects I (joint session DY/TT)
TT 40.7: Talk
Wednesday, March 20, 2024, 11:45–12:00, A 151
Critical Casimir forces for quenched surface disorder in the 2d Ising model — Luca Cervellera and •Fred Hucht — Fakultät für Physik, Universität Duisburg-Essen
For the anisotropic square-lattice Ising model, the critical Casimir amplitude and force can be calculated exactly for many geometries and boundary conditions. From a recent exact solution for the cylinder with length L, circumference M, and with arbitrary quenched random boundary conditions at one boundary, we determine the full density of thermodynamic states ω(f(ex), mB), with excess free energy per boundary spin f(ex) and boundary magnetization mB, at criticality. From an analysis of this quantity we can derive the disorder averaged Casimir potential and Casimir force for different aspect ratios and disorder ensembles.
Keywords: Critical Casimir forces; square-lattice Ising model; quenched disorder; surface criticality; universality