Mon·Aug 19, 2002Monday·August 19, 2002

1. 01*

   A Test of The Source Galerkin Method

   D. Petrov🇺🇸 · P. Emirdag🇺🇸 · G.S. Guralnik🇺🇸

   Some results of the ongoing development of our Source Galerkin (SG) nonperturbative approach to numerically solving Quantum Field theories are presented. This technique has the potential to be much faster than Monte Carlo methods. SG uses known symmetries and theoretical properties of a theory. In order to test this approach, we applied it to phi^4 theory in zero dimensions. This model has been extensively studied and has a known set of exact solutions. This allows us to broaden the understanding of various properties of the SG method and to develop techniques necessary for the successful application of this method to more sophisticated theories.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·4 citations
2. 02*

   The factorization method for systems with a complex action -a test in Random Matrix Theory for finite density QCD-

   J. Ambjorn (1)🇩🇰 · K.N. Anagnostopoulos (2)🇬🇷 · J. Nishimura (3)🇩🇰 · J.J.M. Verbaarschot (4) ((1) Niels Bohr, (2) Crete, (3) Nagoya, (4) Stony Brook)🇺🇸

   Monte Carlo simulations of systems with a complex action are known to be extremely difficult. A new approach to this problem based on a factorization property of distribution functions of observables has been proposed recently. The method can be applied to any system with a complex action, and it eliminates the so-called overlap problem completely. We test the new approach in a Random Matrix Theory for finite density QCD, where we are able to reproduce the exact results for the quark number density. The achieved system size is large enough to extract the thermodynamic limit. Our results provide a clear understanding of how the expected first order phase transition is induced by the imaginary part of the action.

   hep-latJHEP(2002)·103 citations
3. 03*

   Transiting topological sectors with the overlap

   Michael Creutz🇺🇸

   The overlap operator provides an elegant definition for the winding number of lattice gauge field configurations. Only for a set of configurations of measure zero is this procedure undefined. Without restrictions on the lattice fields, however, the space of gauge fields is simply connected. I present a simple low dimensional illustration of how the eigenvalues of a truncated overlap operator flow as one travels between different topological sectors.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·7 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.