Mon·Dec 3, 2001Monday·December 3, 2001

1. 01*

   Numerical study of lattice index theorem usingimproved cooling and overlap fermions

   J. B. Zhang🇦🇺 · S. O. Bilson-Thompson🇦🇺 · F.D.R. Bonnet🇦🇺 · D.B. Leinweber🇦🇺 · A.G. Williams🇦🇺 · J.M. Zanotti🇦🇺

   We investigate topological charge and the index theorem on finite lattices numerically. Using mean field improved gauge field configurations we calculate the topological charge Q using the gluon field definition with $\mathcal{O}(a^4)$-improved cooling and an $\mathcal{O}(a^4)$-improved field strength tensor $F_{\mu \nu }$. We also calculate the index of the massless overlap fermion operator by directly measuring the differences of the numbers of zero modes with left- and right--handed chiralities. For sufficiently smooth field configurations we find that the gluon field definition of the topological charge is integer to better than 1% and furthermore that this agrees with the index of the overlap Dirac operator, i.e., the Atiyah-Singer index theorem is satisfied. This establishes a benchmark for reliability when calculating lattice quantities which are very sensitive to topology.

   hep-latPRD(2002)·20 citations
2. 02*

   Reaching the continuum limit in lattice gauge theory - without a computer

   John A.L. McIntosh🇦🇺 · Lloyd C.L. Hollenberg🇦🇺

   The scaling slope of the anti-symmetric mass gap M of compact U(1)_{2+1} lattice gauge theory is obtained analytically in the Hamiltonian formalism using the plaquette expansion. Based on the first four moments of the Hamiltonian with respect to a one-plaquette mean field state the results demonstrate clear scaling of M at and beyond the transition from strong to weak coupling. The scaling parameters determined agree well with the range of numerical determinations available.

   hep-latPLB(2002)·3 citations
3. 03*

   Overlap and domain wall fermions: what is the price of chirality?

   Karl Jansen🇩🇪

   In this contribution the costs of simulations employing domain wall and overlap fermions are estimated. In the discussion we will stay within the quenched approximation.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·8 citations
4. 04*

   Investigating QCD Vacuum on the lattice

   A. Di Giacomo🇮🇹

   Investigations on the structure of QCD vacuum from first principles can be done on the lattice. The mechanism of confinement is an example: results from lattice on it are reviewed.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·0 citations
5. 05*

   The critical point of lattice QCD on the \mu-T plane

   Z. Fodor🇭🇺 · S.D. Katz🇩🇪

   We propose a method to study lattice QCD at finite temperature and chemical potential. We compare it with direct results and with the Glasgow method by using n_f=4 QCD at Im(\mu)\neq 0. We locate the critical endpoint (E) of QCD on the Re(\mu)-T plane. In this study we use n_f=2+1 dynamical staggered quarks with semi-realistic masses on L_t=4 lattices.

   hep-latPoS(2001)·3 citations
6. 06*

   Three-dimensional gonihedric spin system

   G.Koutsoumbas🇬🇷 · G.K.Savvidy🇬🇷

   We perform Monte Carlo simulations of a three-dimensional spin system with a Hamiltonian which contains only four-spin interaction term. This system describes random surfaces with extrinsic curvature - gonihedric action. We study the anisotropic model when the coupling constants ${\beta }_S$ for the space-like plaquettes and ${\beta }_T$ for the transverse-like plaquettes are different. In the two limits ${\beta }_S=0$ and ${\beta }_T=0$ the system has been solved exactly and the main interest is to see what happens when we move away from these points towards the isotropic point, where we recover the original model. We find that the phase transition is of first order for ${\beta }_T={\beta }_S\approx 0.25,$ while away from this point it becomes weaker and eventually turns to a crossover. The conclusion which can be drown from this result is that the exact solution at the point ${\beta }_S=0$ in terms of 2d-Ising model should be considered as a good zero order approximation in the description of the system also at the isotropic point ${\beta }_S={\beta }_T$ and clearly confirms the earlier findings that at the isotropic point the original model shows a first order phase transition.

   ↳ cond-mathep-lathep-thMod.Phys.Lett.A(2002)·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.