ar X iv : h ep - l at / 9 70 90 18 v 1 9 S ep 1 99 7 1 A fixed - point action for the lattice Schwinger model ∗
نویسنده
چکیده
We determine non-perturbatively a fixed-point (FP) action for fermions in the two-dimensional U(1) gauge (Schwinger) model. Our parameterization for the fermionic action has terms within a 7× 7 square on the lattice, using compact link variables. With the Wilson fermion action as starting point we determine the FP-action by iterating a block spin transformation (BST) with a blocking factor of 2 in the background of non-compact gauge field configurations sampled according to the (perfect) Gaussian measure. We simulate the model at various values of β and find excellent improvement for the studied observables.
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