New proposal for numerical simulations of theta-vacuum like systems

TL;DR

This paper introduces a novel numerical simulation method for theta-vacuum systems, successfully tested on solvable models and applied to CP^3, avoiding unphysical phase transitions and accurately reproducing analytical results.

Contribution

The paper presents a new approach to simulate theta-vacuum systems, particularly focusing on computing the topological charge distribution without unphysical phase transitions.

Findings

No unphysical phase transitions observed

Accurate reproduction of analytical results within a few percent

Effective application to CP^3 model

Abstract

We propose a new approach to perform numerical simulations of theta-vacuum like systems, test it in two analytically solvable models, and apply it to CP^3. The main new ingredient in our approach is the method used to compute the probability distribution function of the topological charge at theta=0. We do not get unphysical phase transitions (flattening behavior of the free energy density) and reproduce the exact analytical results for the order parameter in the whole theta-range within a few percent.