Topological Factors Derived From Bohmian Mechanics
  We derive for Bohmian mechanics topological factors for quantum systems with a multiply-connected configuration space Q. These include nonabelian factors corresponding to what we call holonomy-twisted representations of the fundamental group of Q. We employ wave functions on the universal covering space of Q. As a byproduct of our analysis, we obtain an explanation, within the framework of Bohmian mechanics, of the fact that the wave function of a system of identical particles is either symmetric or anti-symmetric. 
Detlef Duerr, Sheldon Goldstein, James Taylor, Roderich Tumulka, Nino   Zanghi