Quantum Encounters Seminar -- Quantum Information, Condensed Matter, Quantum Field Theory

Hidden Critical Points in the Two-Dimensional O(n>2) model: Exact Numerical Study of a Complex Conformal Field Theory

by Prof. Thomas Scaffidi (UC Irvine)

Centre de conférences Marilyn et James Simons (IHES)

Centre de conférences Marilyn et James Simons


Le Bois-Marie 35, route de Chartres 91440 Bures-sur-Yvette

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. 

Participer à la réunion Zoom

ID de réunion : 857 6661 0072
Code secret : 966618


Pour être informé des prochains séminaires vous pouvez vous abonner à la liste de diffusion en écrivant un mail à sympa@listes.math.cnrs.fr avec comme sujet: "subscribe quantum_encounters_seminar PRENOM NOM"
(indiquez vos propres prénom et nom) et laissez le corps du message vide.

Organized by

Slava Rychkov