Thomas Kalkreuter

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Recently, Kalkreuter obtained complete Dirac spectra for SU (2) lattice gauge theory both for staggered fermions and for Wilson fermions. The lattice size was as large as 12 4. We performed a statistical analysis of these data and found that the eigenvalue correlations can be described by the Gaussian Symplectic Ensemble for staggered fermions and by the(More)
We present evidence that multigrid works for wave equations in disordered systems, e.g. in the presence of gauge elds, no matter how strong the disorder, but one needs to introduce a \neural computations" point of view into large scale simulations: First, the system must learn how to do the simulations eeciently, then do the simulation (fast). The method(More)
Multigrid (MG) methods for the computation of propagators of staggered fermions in non-Abelian gauge fields are discussed. MG could work in principle in arbitrarily disordered systems. The practical variational MG methods tested so far with a " Laplacian choice " for the restriction operator are not competitive with the conjugate gradient algorithm on(More)
EEective eld theories encode the predictions of a quantum eld theory at low energy. The eeective theory has a fairly low ultraviolet cutoo. As a result, loop corrections are small, at least if the eeective action contains a term which is quadratic in the elds, and physical predictions can be read straight from the eeective Lagrangean. Methods will be(More)
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