2,238 research outputs found

    Killing spinor space-times and constant-eigenvalue Killing tensors

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    A class of Petrov type D Killing spinor space-times is presented, having the peculiar property that their conformal representants can only admit Killing tensors with constant eigenvalues.Comment: 11 pages, submitted to CQ

    Rotating solenoidal perfect fluids of Petrov type D

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    We prove that aligned Petrov type D perfect fluids for which the vorticity vector is not orthogonal to the plane of repeated principal null directions and for which the magnetic part of the Weyl tensor with respect to the fluid velocity has vanishing divergence, are necessarily purely electric or locally rotationally symmetric. The LRS metrics are presented explicitly.Comment: 6 pages, no figure

    Petrov type D pure radiation fields of Kundt's class

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    We present all Petrov type D pure radiation space-times, with or without cosmological constant, with a shear-free, non-diverging geodesic principal null congruence

    Algebraically general, gravito-electric rotating dust

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    The class of gravito-electric, algebraically general, rotating `silent' dust space-times is studied. The main invariant properties are deduced. The number t0t_0 of functionally independent zero-order Riemann invariants satisfies 1≤t0≤21\leq t_0\leq 2 and special attention is given to the subclass t0=1t_0=1. Whereas there are no Λ\Lambda-term limits comprised in the class, the limit for vanishing vorticity leads to two previously derived irrotational dust families with Λ>0\Lambda>0, and the shear-free limit is the G\"{o}del universe.Comment: 10 pages, changed to revtex style, extended discussion section, minor correction

    The deformation complex is a homotopy invariant of a homotopy algebra

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    To a homotopy algebra one may associate its deformation complex, which is naturally a differential graded Lie algebra. We show that infinity quasi-isomorphic homotopy algebras have L-infinity quasi-isomorphic deformation complexes by an explicit construction.Comment: A revised version. The final version will appear in the volume "Current Developments and Retrospectives in Lie Theory

    Purely radiative irrotational dust spacetimes

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    We consider irrotational dust spacetimes in the full non-linear regime which are "purely radiative" in the sense that the gravitational field satisfies the covariant transverse conditions div(H) = div(E) = 0. Within this family we show that the Bianchi class A spatially homogeneous dust models are uniquely characterised by the condition that HH is diagonal in the shear-eigenframe.Comment: 6 pages, ERE 2006 conference, minor correction

    Shear-free perfect fluids with a solenoidal electric curvature

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    We prove that the vorticity or the expansion vanishes for any shear-free perfect fluid solution of the Einstein field equations where the pressure satisfies a barotropic equation of state and the spatial divergence of the electric part of the Weyl tensor is zero.Comment: 9 page

    Purely radiative perfect fluids

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    We study `purely radiative' (div E = div H = 0) and geodesic perfect fluids with non-constant pressure and show that the Bianchi class A perfect fluids can be uniquely characterized --modulo the class of purely electric and (pseudo-)spherically symmetric universes-- as those models for which the magnetic and electric part of the Weyl tensor and the shear are simultaneously diagonalizable. For the case of constant pressure the same conclusion holds provided one also assumes that the fluid is irrotational.Comment: 12 pages, minor grammatical change

    Shearfree perfect fluids with solenoidal magnetic curvature and a gamma-law equation of state

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    We show that shearfree perfect fluids obeying an equation of state p=(gamma -1) mu are non-rotating or non-expanding under the assumption that the spatial divergence of the magnetic part of the Weyl tensor is zero.Comment: 11 page
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