We study lattice two-color QCD (QC2D) with two flavors of staggered fermions at imaginary and real quark chemical potential μq and T>Tc. We employ various methods of extrapolation of the quark number density from imaginary to real quark chemical potentials μq, including series expansions as well as analytic continuation based on phenomenological models, and study their accuracy by comparing the results to the lattice data. Below the Roberge-Weiss temperature, T<TRW, we find that the cluster expansion model provides an accurate analytic continuation of the baryon number density in the studied range of chemical potentials. On the other hand, the behavior of the reconstructed canonical partition functions indicates that the available models may require corrections at high quark densities. At T>TRW we show that the analytic continuation to the real values of μq based on trigonometric functions works equally well with the conventional method based on the Taylor expansion in powers of μq.
@article{arxiv.2103.07442,
title = {Quark Density in Lattice QC$_2$D at Imaginary and Real Chemical Potential},
author = {A. Begun and V. G. Bornyakov and N. V. Gerasimeniuk and V. A. Goy and A. Nakamura and R. N. Rogalyov},
journal= {arXiv preprint arXiv:2103.07442},
year = {2024}
}