Many-flavor Schwinger model at finite chemical potential

We study thermodynamic properties of the Schwinger model on a torus with f flavors of massless fermions and flavor-dependent chemical potentials. Generalizing the two-flavor case, we present a representation of the partition function in the form of a multidimensional theta function and show that the model exhibits a rich phase structure at zero temperature. The different phases, characterized by certain values of the particle numbers, are separated by first-order phase transitions. We work out the phase structure in detail for three and four fermion flavors and conjecture, based on an exploratory investigation of the five, six, and eight flavor case, that the maximal number of coexisting phases at zero temperature grows exponentially with increasing f.Comment: 7 pages, 2 figures, contribution to the 31st International Symposium on Lattice Field Theory - LATTICE 2013, July 29 - August 3, 2013, Mainz, German

Eigenvalue density of Wilson loops in 2D SU(N) YM

In 1981 Durhuus and Olesen (DO) showed that at infinite N the eigenvalue density of a Wilson loop matrix W associated with a simple loop in two-dimensional Euclidean SU(N) Yang-Mills theory undergoes a phase transition at a critical size. The averages of det(z-W), 1/det(z-W), and det(1+uW)/(1-vW) at finite N lead to three different smoothed out expressions, all tending to the DO singular result at infinite N. These smooth extensions are obtained and compared to each other.Comment: 35 pages, 8 figure