# Phase of the Fermion Determinant for QCD at Finite Chemical Potential - High Energy Physics - Lattice

Abstract: In this lecture we discuss various properties of the phase factor of thefermion determinant for QCD at nonzero chemical potential. Its effect onphysical observables is elucidated by comparing the phase diagram of QCD andphase quenched QCD and by illustrating the failure of the Banks-Casher formulawith the example of one-dimensional QCD. The average phase factor and thedistribution of the phase are calculated to one-loop order in chiralperturbation theory. In quantitative agreement with lattice QCD results, wefind that the distribution is Gaussian with a width $\sim \mu T \sqrt V$ for$m \pi \ll T \ll \Lambda { m QCD}$. Finally, we introduce, so-called teflonplated observables which can be calculated accurately by Monte Carlo eventhough the sign problem is severe.

Author: K. Splittorff, J.J.M. Verbaarschot

Source: https://arxiv.org/