Wed·Aug 27, 2003Wednesday·August 27, 2003

1. 01*

   Low-dimensional long-range topological structure in the QCD vacuum

   I. Horvath🇺🇸 · S.J. Dong🇺🇸 · T. Draper🇺🇸 · F.X. Lee🇺🇸 · K.F. Liu🇺🇸 · N. Mathur🇺🇸 · J.B. Zhang🇦🇺 · H.B. Thacker🇺🇸

   Lattice topological charge associated with Ginsparg-Wilson fermions exhibits generic topological stability over quantum ensemble of configurations contributing to the QCD path integral. Moreover, the underlying chiral symmetry leads to the suppression of ultraviolet noise in the associated topological charge densities ("chiral smoothing"). This provides a solid foundation for the direct study of the role of topological charge fluctuations in the physics of QCD vacuum. Using these tools it was recently demonstrated that: (a) there is a well-defined space-time structure (order) in topological charge density (defined through overlap fermions) for typical configurations contributing to QCD path integral; (b) this fundamental structure is low-dimensional, exhibiting sign-coherent behavior on subsets of dimension less than four and not less than one; (c) the structure has a long-range global character (spreading over maximal space-time distances) and is built around the locally one-dimensional network of strong fields (skeleton). In this talk we elaborate on certain aspects and implications of these results.

   hep-latNucl.Phys.B Proc.Suppl.(2004)·19 citations
2. 02*

   A BCS Gap on the Lattice

   David N. Walters🇬🇧 · Simon Hands (U.W.Swansea)🇬🇧

   Monte Carlo simulations of the 3+1 dimensional NJL model are performed with baryon chemical potential mu>0. For mu>Sigma_0, the constituent quark mass in vacuum, chiral symmetry is restored and a diquark condensate <qq_+> forms. We analyse the fermion propagator and find evidence for particle-hole mixing in the vicinity of the Fermi surface and an energy gap Delta>0, both of which provide evidence for superfluidity at high baryon density induced by a BCS mechanism. At (mu a)=0.8 the ratio between the BCS gap and the vacuum quark mass is Delta/Sigma_0=0.15(2).

   hep-lathep-phnucl-thNucl.Phys.B Proc.Suppl.(2004)·3 citations
3. 03*

   General duality for abelian-group-valued statistical-mechanics models

   Sergio Caracciolo🇮🇹 · Andrea Sportiello🇮🇹

   We introduce a general class of statistical-mechanics models, taking values in an abelian group, which includes examples of both spin and gauge models, both ordered and disordered. The model is described by a set of ``variables'' and a set of ``interactions''. A Gibbs factor is associated to each variable and to each interaction. We introduce a duality transformation for systems in this class. The duality exchanges the abelian group with its dual, the Gibbs factors with their Fourier transforms, and the interactions with the variables. High (low) couplings in the interaction terms are mapped into low (high) couplings in the one-body terms. The idea is that our class of systems extends the one for which the classical procedure 'a la Kramers and Wannier holds, up to include randomness into the pattern of interaction. We introduce and study some physical examples: a random Gaussian Model, a random Potts-like model, and a random variant of discrete scalar QED. We shortly describe the consequence of duality for each example.

   ↳ cond-mat.stat-mechcond-mat.dis-nnhep-latmath.COJ.Phys.A(2004)·3 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.