Scaling topological charge in the CP^3 spin model

TL;DR

This paper investigates the CP^3 spin model at large correlation lengths, demonstrating reduced critical slowing down with an overrelaxation algorithm, and reports a new universal scaling result for the topological susceptibility.

Contribution

The study introduces an effective overrelaxation algorithm for the CP^3 model and provides the first scaling measurement of the universal topological susceptibility.

Findings

Reduced critical slowing down with dynamical exponent z around 1

Confirmation of the absence of asymptotic scaling in massgap and spin susceptibility

Universal topological susceptibility extrapolates to chi_t / m^2 = 0.156(2) in the continuum

Abstract

The CP^3 spin model is simulated at large correlation lengths in two dimensions. An overrelaxation algorithm is employed which yields reduced critical slowing down with dynamical exponents z around unity. We compare our results with recent multigrid data on the massgap m and the spin susceptibility and confirm the absence of asymptotic scaling. As a new result we find scaling for the universal topological susceptibility with values extrapolating to chi_t / m^2 = 0.156(2) in the continuum limit.