Wed·Aug 7, 2002Wednesday·August 7, 2002

1. 01*

   A Geometrical Interpretation of Hyperscaling Breaking in the Ising Model

   G. Andronico🇮🇹 · A. Coniglio🇮🇹 · S. Fortunato🇩🇪

   In random percolation one finds that the mean field regime above the upper critical dimension can simply be explained through the coexistence of infinite percolating clusters at the critical point. Because of the mapping between percolation and critical behaviour in the Ising model, one might check whether the breakdown of hyperscaling in the Ising model can also be intepreted as due to an infinite multiplicity of percolating Fortuin-Kasteleyn clusters at the critical temperature T_c. Preliminary results suggest that the scenario is much more involved than expected due to the fact that the percolation variables behave differently on the two sides of T_c.

   hep-latcond-matNucl.Phys.B Proc.Suppl.(2003)·3 citations
2. 02*

   One loop calculation of the renormalised anisotropy for improved anisotropic gluon actions on a lattice

   I.T. Drummond🇬🇧 · A. Hart🇬🇧 · R.R. Horgan🇬🇧 · L.C. Storoni (Cambridge)🇬🇧

   Using the infrared dispersion relation of the on shell gluon, we calculate the renormalisation of the the anisotropy to one loop in perturbation theory for lattice Yang-Mills theories, including the Wilson action and actions with Symanzik and/or tadpole improvement. Using twisted boundary conditions as a gauge invariant infrared regulator, we show for an SU(3) gauge group in D=3+1 dimensions that the one loop anisotropy is accurate to O(3%) for a range of g^2 and chi covering current simulations. In doing so we also present Feynman rules for SU(N) gauge groups with generic anisotropy structure (including `3+1' and `2+2' cases).

   hep-latPRD(2002)·25 citations
3. 03*

   BCS Diquark Condensation in the 3+1d Lattice NJL Model

   David N. Walters (U.W.Swansea)🇬🇧

   We present preliminary evidence of BCS diquark condensation in the 3+1 dimensional Nambu-Jona-Lasinio (NJL) model at non-zero chemical potential (mu) on the lattice. Large N results are used to match the model's parameters to low energy, zero density phenomenology. A diquark source j is added in a partially quenched approximation to enable the measurement of lattice diquark observables. In particular measurements are made of the diquark condensate and susceptibilities as functions of j which support the existence of a BCS phase at high mu.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·4 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.