Pantheon SEMPARIS Le serveur des séminaires parisiens Paris

Statut Confirmé
Série PT-IHES
Domaines cond-mat,hep-th,quant-ph
Date Mercredi 29 Mars 2023
Heure 16:00
Institut IHES
Salle Centre de conférences Marilyn et James Simons
Nom de l'orateur Scaffidi
Prenom de l'orateur Thomas
Addresse email de l'orateur
Institution de l'orateur UC Irvine
Titre Hidden Critical Points in the Two-Dimensional O(n>2) model: Exact Numerical Study of a Complex Conformal Field Theory
Résumé 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.
Numéro de preprint arXiv
Commentaires + d'infos : https://indico.math.cnrs.fr/event/9621/
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