Numerical study of the enlarged O(5) symmetry of the 3-D antiferromagnetic RP2 spin model

TL;DR

This study uses Monte Carlo simulations and finite-size scaling to analyze the critical behavior of 3D O(5) and RP2 models, revealing they share a universality class with a complex phase diagram.

Contribution

It provides high-precision estimates of critical exponents and demonstrates the universality of the O(5) and RP2 models under specific conditions.

Findings

Both models belong to the same universality class.

The phase diagram of the extended RP2 model contains mostly first-order transitions.

Critical exponents and universal quantities are accurately estimated.

Abstract

We investigate by means of Monte Carlo simulation and Finite-Size Scaling analysis the critical properties of the three dimensional O(5) non linear sigma model and of the antiferromagnetic RP2 model, both of them regularized on a lattice. High accuracy estimates are obtained for the critical exponents, universal dimensionless quantities and critical couplings. It is concluded that both models belong to the same Universality Class, provide that rather non standard identifications are made for the momentum-space propagator of the RP2 model. We have also investigated the phase diagram of the RP2 model extended by a second-neighbor interaction. A rich phase diagram is found, where most phase transitions are first order.