5,247 research outputs found
't Hooft loop and the phases of SU(2) LGT
We analyze the vacuum structure of SU(2) lattice gauge theories in D=2,3,4,
concentrating on the stability of 't Hooft loops. High precision calculations
have been performed in D=3; similar results hold also for D=4 and D=2. We
discuss the impact of our findings on the continuum limit of Yang-Mills
theories.Comment: 7 pages, 3 figures. Presented at the 31st International Symposium on
Lattice Field Theory (Lattice 2013), 29 July - 3 August 2013, Mainz, German
Non perturbative study of QCD on a 2+2 anisotropic lattice
We present preliminary results for a non perturbative determination of the
parameters in the action required to restore Lorentz invariance in long
distance correlators, using the static interquark potential. Comparison with
analytical results is made and further applications are discussed.Comment: 3 pages, Lattice2003 (improvement
High-precision computation of two-loop Feynman diagrams with Wilson fermions
We apply the coordinate-space method by Luescher and Weisz to the computation
of two-loop diagrams in full QCD with Wilson fermions on the lattice. The
essential ingredient is the high-precision determination of mixed
fermionic-bosonic propagators.Comment: Talk presented at Lattice '97 (Theoretical Developments), Edinburgh
(UK), July 1997. LaTeX2e, 3 pages, uses espcrc2. Report DESY 97-18
Numerical Stochastic Perturbation Theory. Convergence and features of the stochastic process. Computations at fixed (Landau) Gauge
Concerning Numerical Stochastic Perturbation Theory, we discuss the
convergence of the stochastic process (idea of the proof, features of the limit
distribution, rate of convergence to equilibrium). Then we also discuss the
expected fluctuations in the observables and give some idea to reduce them. In
the end we show that also computation of quantities at fixed (Landau) Gauge is
now possible.Comment: 3 pages. Contributed to 17th International Symposium on Lattice Field
Theory (LATTICE 99), Pisa, Italy, 29 Jun - 3 Jul 199
Hybrid star structure with the Field Correlator Method
We explore the relevance of the color-flavor locking phase in the equation of
state (EoS) built with the Field Correlator Method (FCM) for the description of
the quark matter core of hybrid stars. For the hadronic phase, we use the
microscopic Brueckner-Hartree-Fock (BHF) many-body theory, and its relativistic
counterpart, i.e. the Dirac-Brueckner (DBHF). We find that the main features of
the phase transition are directly related to the values of the quark-antiquark
potential , the gluon condensate and the color-flavor
superconducting gap . We confirm that the mapping between the FCM and
the CSS (constant speed of sound) parameterization holds true even in the case
of paired quark matter. The inclusion of hyperons in the hadronic phase and its
effect on the mass-radius relation of hybrid stars is also investigated.Comment: 15 pages, 8 figures ; revised version to be published in the EPJA
Topical Issue on "Exotic Matter in Neutron Stars
Beta-function, Renormalons and the Mass Term from Perturbative Wilson Loops
Several Wilson loops on several lattice sizes are computed in Perturbation
Theory via a stochastic method. Applications include: Renormalons, the Mass
Term in Heavy Quark Effective Theory and (possibly) the beta-function.Comment: 3 pages, 1 eps figure. Contributed to 17th International Symposium on
Lattice Field Theory (LATTICE 99), Pisa, Italy, 29 Jun - 3 Jul 199
Ghost propagator and the Coulomb form factor from the lattice
We calculate the Coulomb ghost propagator G(|p|) and the static Coulomb
potential V_C(|r|) for SU(2) Yang-Mills theory on the lattice. In view of
possible scaling violations related to deviations from the Hamiltonian limit we
use anisotropic lattices to improve the temporal resolution. We find that the
ghost propagator is infrared enhanced with an exponent kappa_gh ~ 0.5 while the
Coulomb potential exhibits a string tension larger than the Wilson string
tension, sigma_C ~ 2 sigma. This agrees with the Coulomb "scaling" scenario
derived from the Gribov-Zwanziger confinement mechanism.Comment: 23 pages, 5 figures. Some issues clarified and extended, references
added. To appear in PR
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