On the Meissner effect in SU(2) lattice gauge theory

We investigate the dual superconductor model of color confinement in SU(2) lattice gauge theory. We find that the transverse distribution of the longitudinal chromoelectric field between static quarks displays the dual Meissner effect. We also give evidence that the problem of color confinement could be approached in the framework of the 't~Hooft's Abelian projection.Comment: 3 pages, PostScript. Contribution to the LATTICE 93 Conference (Dallas, U.S.A., September 1993) preprint BARI-TH-161/9

Cosmic acceleration and f(R)f(R) theory: perturbed solution in a matter FLRW model

In the present paper we consider $f(R)$ gravity theories in the metric approach and we derive the equations of motion, focusing also on the boundary conditions. In such a way we apply the general equations to a first order perturbation expansion of the Lagrangian. We present a model able to fit supernovae data without introducing dark energy.Comment: 10 pages, 1 figur