ar X iv : g r - qc / 0 10 50 68 v 1 1 8 M ay 2 00 1 Kinematics of a Spacetime with Infinite Λ and c

ar X iv : g r - qc / 0 00 50 66 v 1 1 6 M ay 2 00 0 SELF - SIMILAR PERFECT FLUIDS

Space-times admitting an r-parameter Lie group of homotheties are studied for r > 2 devoting a special attention to those representing perfect fluid solutions to Einstein's field equations. 1 Basic facts about homotheties Throughout this paper (M, g) will denote a space-time: M then being a Haus-dorff, simply connected, four-dimensional manifold, and g a Lorentz metric of signature (-,+,+,+). A...

ar X iv : g r - qc / 0 50 51 30 v 1 2 6 M ay 2 00 5 An Exact Solution for Static Scalar Fields Coupled to Gravity in ( 2 + 1 ) - Dimensions

We obtain an exact solution for the Einstein’s equations with cosmological constant coupled to a scalar, static particle in static, ”spherically” symmetric background in 2 + 1 dimensions. ————————————————————————————

ar X iv : g r - qc / 0 00 90 67 v 2 9 M ay 2 00 1 Berry phase for spin – 1 / 2 particles moving in a spacetime with torsion

Berry phase for a spin–1/2 particle moving in a flat spacetime with torsion is investigated in the context of the Einstein-Cartan-Dirac model. It is shown that if the torsion is due to a dense polarized background, then there is a Berry phase only if the fermion is massless and its momentum is perpendicular to the direction of the background polarization. The order of magnitude of this Berry ph...

ar X iv : g r - qc / 0 51 01 27 v 1 3 1 O ct 2 00 5 Imprints of Spacetime Topology in the Hawking - Unruh Effect

ar X iv : 0 70 5 . 04 59 v 1 [ gr - q c ] 3 M ay 2 00 7 Bianchi Type - I Cosmological Models with Variable G and Λ - Term in General Relativity

Einstein’s field equations with variable gravitational and cosmological “constant” are considered in presence of perfect fluid for Bianchi type-I spacetime. Consequences of the four cases of the phenomenological decay of Λ have been discussed which are consistent with observations. The physical significance of the cosmological models have also been discussed. PACS: 98.80.Es, 98.80.-k