Chiral symmetry breaking in the Wegner-Houghton approach

The Wegner-Houghton formulation of the exact renormalization group evolution equation is used in order to study the chiral symmetry breaking of the linear sigma model coupled to an isospin doublet of quarks. A numerical investigation for a particular truncation of the equation which includes the scalar field renormalization function is presented.Comment: 4 pages,4 eps figures. Contribution to CRIS2000, Catania, May 200

Two loop results from the derivative expansion of the blocked action

A derivative expansion of the Wegner-Houghton equation is derived for a scalar theory. The corresponding full non-perturbative renormalization group equations for the potential and the wave-function renormalization function are presented. We also show that the two loop perturbative anomalous dimension for the O(N) theory can be obtained by means of a polynomial truncation in the field dependence in our equations.Comment: 4 pages, RevTeX, no figure

Symmetry breaking in non-commutative cut-off field theories

The relation between symmetry breaking in non-commutative cut-off field theories and transitions to inhomogeneous phases in condensed matter and in finite density QCD is discussed. The non-commutative dynamics, with its peculiar infrared-ultraviolet mixing, can be regarded as an effective description of the mechanisms which lead to inhomogeneous phase transitions and a roton-like excitation spectrum.Comment: LaTex, 3 pages,Talk given at "Quark Confinement and the Hadron Spectrum VI", 21-25 September 2004, Villasimius, Ital

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