Fisher’s zeros of quasi-Gaussian densities of states

Abstract

We discuss apparent paradoxes regarding the location of the zeros of the partition function in the complex $\ensuremath{\beta}$ plane (Fisher's zeros) of a pure $SU(2)$ lattice gauge theory in 4 dimensions. We propose a new criterion to draw the region of the complex $\ensuremath{\beta}$ plane where reweighting methods can be trusted when the density of states is almost but not exactly Gaussian. We propose new methods to infer the existence of zeros outside of this region. We demonstrate the reliability of these proposals with quasi-Gaussian Monte Carlo distributions where the locations of the zeros can be calculated by independent numerical methods. The results are presented in such a way that the methods can be applied for general lattice models. Applications to specific lattice models will be discussed in a separate publication.