Lee-Yang zeroes in the one flavour massive lattice Schwinger model

Abstract

We study the partition function of the model formulated with Wilson fermions with only one species, both analytically and numerically. At strong coupling we construct the solution for lattice size up to $8\times 8$, a polynomial in the hopping parameter up to $O(\ka^{128})$. At $\be>0$ we evaluate the expectation value of the fermion determinant for complex values of $\ka$. From the Lee-Yang zeroes we find support for the existence of a line of phase transitions from $(\be=0, \ka\simeq 0.38)$ up to $(\be=\infty, \ka=1/4)$.