Dual lattice representations for O(N) and CP(N-1) models with a chemical potential

TL;DR

This paper develops dual lattice representations for O(N) and CP(N-1) models that eliminate the complex action problem at finite chemical potential, enabling Monte Carlo simulations across all chemical potentials.

Contribution

The authors derive new dual formulations for O(N) and CP(N-1) models that ensure positive real contributions, overcoming the complex action problem in lattice simulations.

Findings

Dual representations have only real, positive contributions at finite chemical potential.

Monte Carlo simulations are feasible at arbitrary chemical potential using the dual variables.

The approach overcomes the complex action problem in lattice models.

Abstract

We derive dual representations for O(N) and CP(N-1) models on the lattice. In terms of the dual variables the partition sums have only real and positive contributions also at finite chemical potential. Thus the complex action problem of the conventional formulation is overcome and using the dual variables Monte Carlo simulations are possible at arbitrary chemical potential.