447 research outputs found
Anisotropic Gauge Theories: A Numerical Study of the Fu-Nielsen Model
We study numerically 4+1 dimensional pure gauge theory.Comment: To appear in the proceedings of Lattice'94, held in Bielefeld,
German
Multigrid for propagators of staggered fermions in four-dimensional gauge fields
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 lattices up to .
Numerical results are presented for propagators in gauge fields.Comment: 4 pages, 3 figures (one LaTeX-figure, two figures appended as
encapsulated ps files); Contribution to LATTICE '92, requires espcrc2.st
The Network Nullspace Property for Compressed Sensing of Big Data over Networks
We present a novel condition, which we term the net- work nullspace property,
which ensures accurate recovery of graph signals representing massive
network-structured datasets from few signal values. The network nullspace
property couples the cluster structure of the underlying network-structure with
the geometry of the sampling set. Our results can be used to design efficient
sampling strategies based on the network topology
Some Comments on Multigrid Methods for Computing Propagators
I make three conceptual points regarding multigrid methods for computing
propagators in lattice gauge theory: 1) The class of operators handled by the
algorithm must be stable under coarsening. 2) Problems related by symmetry
should have solution methods related by symmetry. 3) It is crucial to
distinguish the vector space from its dual space . All the existing
algorithms violate one or more of these principles.Comment: 16 pages, LaTeX plus subeqnarray.sty (included at end),
NYU-TH-93/07/0
Critical Slowing-Down in Landau Gauge-Fixing Algorithms
We study the problem of critical slowing-down for gauge-fixing algorithms
(Landau gauge) in lattice gauge theory on a -dimensional lattice. We
consider five such algorithms, and lattice sizes ranging from to
(up to in the case of Fourier acceleration). We measure four
different observables and we find that for each given algorithm they all have
the same relaxation time within error bars. We obtain that: the so-called {\em
Los Alamos} method has dynamic critical exponent , the {\em
overrelaxation} method and the {\em stochastic overrelaxation} method have , the so-called {\em Cornell} method has slightly smaller than
and the {\em Fourier acceleration} method completely eliminates critical
slowing-down. A detailed discussion and analysis of the tuning of these
algorithms is also presented.Comment: 40 pages (including 10 figures). A few modifications, incorporating
referee's suggestions, without the length reduction required for publicatio
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