Speaker
Prof.
Jacobus Verbaarschot
(Stony Brook University)
Description
In a sector of fixed topological charge, the chiral condensate has a discontinuty given by the Banks-Casher formula also in the case of one-flavor QCD. However, at fixed $\theta$ angle, the chiral condensate remains constant when the quark mass crosses zero. To reconcile these contradictory observations, we have evaluated the spectral density of one-flavor QCD at $\theta=0$. For negative quark mass, it becomes a strongly oscillating function with a period given by the inverse space-time volume and an amplitude that increases expoentially with the space-time volume. As we have learned from QCD at nonzero chemical potential, if this is the case, an alternative to the Banks-Casher formula applies, and we will demonstrate that for one-flavor QCD, this results into a continuous chiral condensate. A special role is played by the topological zero modes which have to be taken into account exactly in order to get a finite chiral condensate in the thermodynamic limit.
Primary authors
Prof.
Jacobus Verbaarschot
(Stony Brook University)
Prof.
Tilo Wettig
(University of Regensburg)
