Pantheon SEMPARIS Le serveur des séminaires parisiens Paris

Status Confirmed
Seminar Series PT-IHES
Subjects cond-mat,hep-th,quant-ph
Date Wednesday 29 March 2023
Time 16:00
Institute IHES
Seminar Room Centre de conférences Marilyn et James Simons
Speaker's Last Name Scaffidi
Speaker's First Name Thomas
Speaker's Email Address
Speaker's Institution UC Irvine
Title Hidden Critical Points in the Two-Dimensional O(n>2) model: Exact Numerical Study of a Complex Conformal Field Theory
Abstract The presence of nearby conformal field theories (CFTs) hidden in the complex plane of the tuning parameter was recently proposed as an elegant explanation for the ubiquity of "weakly first-order" transitions in condensed matter and high-energy systems. In this work, we perform an exact microscopic study of such a complex CFT (CCFT) in the two-dimensional O(n) loop model. The well-known absence of symmetry-breaking of the O(n>2) model is understood as arising from the displacement of the non-trivial fixed points into the complex temperature plane. Thanks to a numerical finite-size study of the transfer matrix, we confirm the presence of a CCFT in the complex plane and extract the real and imaginary parts of the central charge and scaling dimensions. By comparing those with the analytic continuation of predictions from Coulomb gas techniques, we determine the range of validity of the analytic continuation to extend up to ng≈12.34, beyond which the CCFT gives way to a gapped state. Finally, we propose a beta function which reproduces the main features of the phase diagram and which suggests an interpretation of the CCFT as a liquid-gas critical point at the end of a first-order transition line.
arXiv Preprint Number
Comments + d'infos : https://indico.math.cnrs.fr/event/9621/
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