N ov 1 99 8 Distributional torsion of cosmic walls crossed by cosmic strings

Distributional sources of cosmic walls crossed by cosmic strings from Riemann-Cartan (RC) Geometry. The matter density of the planar wall is maximum at the point where the cosmic string crosses the cosmic wall. Cartan torsion is has a support on the cosmic string given by the Dirac δ-function. Off the sources are left with a torsionless vacuum. PACS number(s) : 0420,0450,1127 Departamento de F́ısica Teórica Instituto de F́ısica UERJ Rua São Fco. Xavier 524, Rio de Janeiro, RJ Maracanã, CEP:20550-003 , Brasil. E-Mail.: [email protected] Distributional torsion of cosmic walls crossed by cosmic strings. 2 Recently Bezerra and Letelier [1, 2] have considered holonomy transformations to detect the presence of space-time defects [3] such as cosmic strings and domain walls. In one of their examples [2] they considered a topological plane crossed by a cosmic string in the context of General Relativity (GR) where the space-time metric was given in terms of coordinates (t, z, ρ, φ) by [9] ds = e (dt + dz)− ρe(dρ + ρdφ) (1) Where F and H depends on variable z orthogonal to the wall and λ is the mass density the cosmic string. According to Cartan’s calculus of exterior differential forms, metric (1) can be reexpressed ω = e F 2 dt