Numerical implementation of U(1) chiral lattice gauge theories in two-dimensions Presenter: Yoshio Kikukawa Daisuke Kadoh, Yoshio Kikukawa Abstract: We consider a numerical method to formulate U(1) chiral gauge theories on the lattice with exact gauge invariance. In two-dimensional case, the gauge invariant Weyl fermion measure is explicitly worked out and the locality and gauge-invarinace are checked. In our approach, the local cohomology problem is solved within a finite volume lattice by reformulating the Poincaré lemma so that it holds true on the finite lattice up to exponentially small corrections. With this solution, the fermion measure is reconstructed by the parameter integration performed with a Gaussian Quadrature formula, which turns out to show rather good convergence for the admissible fields. We also examine the numerical implementation of the field tensor-based method for the cohomological analysis, by which the parameter integration can be omitted completely. (based on hep-lat/0309022, hep-lat/0401025, hep-lat/0504021) 1