Dual lattice simulation of the abelian gauge-Higgs model at finite density: an exploratory proof of concept study.

The U(1) gauge-Higgs model with two flavors of opposite charge and a chemical potential is mapped exactly to a dual representation where matter fields correspond to loops of flux and the gauge fields are represented by surfaces. The complex action problem of the conventional formulation at finite chemical potential μ is overcome in the dual representation, and the partition sum has only real and nonzero contributions. We simulate the model in the dual representation using a generalized worm algorithm, explore the phase diagram, and study condensation phenomena at finite μ.

QCD phase diagram according to the center group.

We study an effective theory for QCD at finite temperature and density which contains the leading center symmetric and center symmetry breaking terms. The effective theory is studied in a flux representation where the complex phase problem is absent and the model becomes accessible to Monte Carlo techniques also at finite chemical potential. We simulate the system by using a generalized Prokof'ev-Svistunov worm algorithm and compare the results to a low temperature expansion.