1,745 research outputs found
A 0-dimensional counter-example to rooting?
We provide an example of a 0-dimensional field theory where rooting does not
work.Comment: 3 pages; Physics Letters B (2010
The Quenched Continuum Limit
We show that all current formalisms for quarks in lattice QCD are consistent
in the quenched continuum limit, as they should be. We improve on previous
extrapolations to this limit, and the understanding of lattice systematic
errors there, by using a constrained fit including both leading and sub-leading
dependence on a.Comment: Poster presented at Lattice2004(spectrum), Fermilab, June 21-26, 200
Speeding up Lattice QCD simulations with clover-improved Wilson Fermions
We apply a recent proposal to speed up the Hybrid-Monte-Carlo simulation of
systems with dynamical fermions to two flavour QCD with clover-improvement. The
basic idea of our proposal is to split the fermion matrix into two factors with
a reduced condition number each. In the effective action, for both factors a
pseudo-fermion field is introduced. For our smallest quark masses we see a
speed-up of more than a factor of two compared with the standard algorithm.Comment: 26 pages, 2 figure
Enantioselective Conjugate Addition of Grignard Reagents to Enones Catalyzed by Chiral Zinc(II) Complexes
Various chiral zinc(II) complexes catalyze the asymmetric 1,4-addition of Grignard reagents to α,β-unsaturated ketones with high chemoselectivities (yields of 1,4-adducts, 83-99%), high regioselectivities (1,4/1,2 ratios up to 499) and modest enantioselectivities (ee up to 33%). A study of several factors, i.e. ligand, solvent, counterions, order and rate of additions, temperature, and the nature of Grignard reagents, that influence the regio- and enantioselectivities is given. Based on the addition of isopropylmagnesium halides to 2-cyclohexenone as a model reaction, it was established that the highest enantioselectivities are reached with in situ prepared zinc complexes derived from optically active diamino alcohol ligands using lithium bases in tetrahydrofuran as the solvent. A mechanistic rationalization is given
Non-Perturbative Renormalisation and Kaon Physics
A general review is presented on the problem of non perturbative computation
of the transition amplitude.Comment: 8 pages, Latex, uses espcrc2.sty, Talk given at LATTICE9
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