Strong coupling lattice Schwinger model on large spherelike lattices

The lattice regularized Schwinger model for one fermion flavor and in the strong coupling limit is studied through its equivalent representation as a restricted 8-vertex model. The Monte Carlo simulation on lattices with torus topology is handicapped by a severe non-ergodicity of the updating algorithm; introducing lattices with spherelike topology avoids this problem. We present a large scale study leading to the identification of a critical point with critical exponent ν=1, in the universality class of the Ising model or, equivalently, the lattice model of free fermions. (orig.)