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 $V_1$, the gluon condensate $G_2$ and the color-flavor superconducting gap $\Delta$. 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

The hadron-quark phase transition in neutron stars

We study the hadron-quark phase transition in the interior of neutron stars (NS). For the hadronic sector, we use a microscopic equation of state (EOS) involving nucleons and hyperons derived within the Brueckner-Hartree-Fock approach. For the quark sector, we employ the MIT bag model, as well as the Nambu--Jona-Lasinio (NJL) and the Color Dielectric (CD) models, and find that the NS maximum masses lie in the interval between 1.5 and 1.8 solar masses.Comment: Talk given at the 18th International Nuclear Physics Divisional Conference of the EPS, Prague, 23-29 August, 2004. To be published in Nuclear Physics A. 4 pages, 1 eps figur

SO(3) Yang-Mills theory on the lattice

We numerically investigate the phase structure of pure SO(3) LGT at zero and non-zero temperature in the presence of a Z2 blind monopole chemical potential. The physical meaning of the different phases, a possible symmetry breaking mechanism as well as the existence of an order parameter for the finite temperature phase transition are discussed.Comment: 3 pages, 2 figures LaTeX file. Uses espcrc2 style and amssymb package. Talk given at Lattice2002(nonzerot), Boston. Corrected version with one added referenc

SO(3) vs. SU(2) Yang-Mills theory on the lattice: an investigation at non-zero temperature

The adjoint SU(2) lattice gauge theory in 3+1 dimensions with the Wilson plaquette action modified by a Z(2) monopole suppression term is reinvestigated with special emphasis on the existence of a finite-temperature phase transition decoupling from the well-known bulk transitions.Comment: 13 pages, 9 figures. Based on contributions to CONFINEMENT 2003 and Lattice2003(topology). To be published in Proceedings of CONFINEMENT 2003, Tokyo, Japa

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

Lattice Coulomb propagators, effective energy and confinement

We show that in the lattice Hamiltonian limit all Coulomb gauge propagators are consistent with the Gribov-Zwanziger confinement mechanism, with an IR enhanced effective energy for quarks and gluons and a diverging ghost form factor compatible with a dual-superconducting vacuum. Multiplicative renormalizability is ensured for all static correlators, while for non-static ones their energy dependence plays a crucial role in this respect. Moreover, from the Coulomb potential we can extract the Coulomb string tension \sigma_C ~ 2 \sigma.Comment: 8 pages, 5 figures. Talk given at the conference "Confinement X, Quark Confinement and the Hadron Spectrum", 8-12 October 2012, TUM Campus Garching, Munich, German