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DY: Fachverband Dynamik und Statistische Physik

DY 49: Critical Phenomena and Phase Transitions

DY 49.9: Vortrag

Donnerstag, 30. März 2023, 17:15–17:30, ZEU 160

Boundary critical behavior of the three-dimensional O(N) universality class — •Francesco Parisen Toldin¹ and Max A. Metlitski² — ¹Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany — ²Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

It was recently realized that the three-dimensional O(N) model exhibits an extraordinary surface universality class for a finite range of N ≥ 2. We investigate the boundary critical behavior by means of high-precision Monte Carlo simulations of an improved model, where leading scaling corrections are suppressed. Contrary to simplified arguments on the bulk-surface phase diagram, and in line with a recent field-theoretical analysis, we find a special surface transition for N=3, with unusual exponents, and an extraordinary phase with logarithmically decaying correlations. For a general N, the existence and universal properties of extraordinary phase are predicted to be controlled by certain amplitudes of the normal universality class, where one applies an explicit symmetry breaking field to the boundary. We extract these universal amplitudes by Monte Carlo simulations for N=2, 3. Our results are in good agreement with direct Monte Carlo studies of the extraordinary universality class serving as a nontrivial quantitative check of the connection between the normal and extraordinary classes.

Ref.: F. Parisen Toldin, Phys. Rev. Lett. 126, 135701 (2021); F. Parisen Toldin, M. A. Metlitski, Phys. Rev. Lett. 128, 215701 (2022)