General relativity and cosmology

Extra-large remnant recoil velocities and spins from near-extremal-Bowen-York-spin black-hole binaries

Sergio Dain, Carlos O. Lousto, and Yosef Zlochower
We evolve equal-mass, equal-spin black-hole binaries with specific spins of a/m~0.925, the highest spins simulated thus far and nearly the largest possible for Bowen-York black holes, in a set of configurations with the spins counteraligned and pointing in the orbital plane, which maximizes the reco ... [Phys. Rev. D 78, 024039 (2008)] published Thu Jul 24, 2008.

Flat rotation curves in Chern-Simons modified gravity

Kohkichi Konno, Toyoki Matsuyama, Yasuhiro Asano, and Satoshi Tanda
We investigate the spacetime of a slowly rotating black hole in the Chern-Simons modified gravity. The long range feature of frame-dragging effect under the Chern-Simon gravity well explains the flat rotation curves of galaxies which is a central evidence of dark matter. Our solution provides a diff ... [Phys. Rev. D 78, 024037 (2008)] published Wed Jul 23, 2008.

Supersymmetric flat direction decay: The prospect of particle production and preheating investigated in the unitary gauge

Anders Basboll
We look at the possibility of nonperturbative particle production after inflation from supersymmetry flat directions produced by rotating eigenstates thereby avoiding the standard adiabaticity conditions. This might lead to preheating and prevent the delay of thermalization of the Universe. We inves ... [Phys. Rev. D 78, 023528 (2008)] published Wed Jul 23, 2008.

Rotating, inhomogeneous dust interior for the BTZ black hole

Cenalo Vaz and K. R. Koehler
We present exact solutions describing rotating, inhomogeneous dust with generic initial data in 2+1 dimensional anti-de Sitter space-time and show how they are smoothly matched to the Banados-Teitelboim-Zanelli (BTZ) solution in the exterior. The metrics, which are the rotational analogues of the 2+ ... [Phys. Rev. D 78, 024038 (2008)] published Wed Jul 23, 2008.

Statistical properties of the linear tidal shear

Vincent Desjacques and Robert E. Smith
Large-scale structures originate from coherent motions induced by inhomogeneities in the primeval gravitational potential. Here, we investigate the two-point statistics of the second derivative of the potential, the tidal shear, under the assumption of Gaussianity. We derive an exact closed form exp ... [Phys. Rev. D 78, 023527 (2008)] published Tue Jul 22, 2008.

Is loop quantization in cosmology unique?

Alejandro Corichi and Parampreet Singh
We reexamine the process of loop quantization for flat isotropic models in cosmology. In particular, we contrast different inequivalent loop quantizations of these simple models through their respective successes and limitations and assess whether they can lead to any viable physical description. We ... [Phys. Rev. D 78, 024034 (2008)] published Tue Jul 22, 2008.

Geodesic equation in Schwarzschild-(anti-)de Sitter space-times: Analytical solutions and applications

Eva Hackmann and Claus Lammerzahl
The complete set of analytic solutions of the geodesic equation in a Schwarzschild-(anti-)de Sitter space-time is presented. The solutions are derived from the Jacobi inversion problem restricted to the set of zeros of the theta function, called the theta divisor. In its final form the solutions can ... [Phys. Rev. D 78, 024035 (2008)] published Tue Jul 22, 2008.

Gravitomagnetism and lunar laser ranging

Michael Soffel, Sergei Klioner, Jurgen Muller, and Liliane Biskupek
The problem of measuring gravitomagnetic effects by means of lunar laser ranging (LLR) is investigated. The relevant terms in the Einstein-Infeld-Hoffmann equations of motion in barycentric coordinates are parametrized by a parameter eta, which is fitted along with other parameters to LLR data and n ... [Phys. Rev. D 78, 024033 (2008)] published Tue Jul 22, 2008.

Comment on ``Can infrared gravitons screen Lambda?''

N. C. Tsamis and R. P. Woodard
We reply to the recent criticism by Garriga and Tanaka of our proposal that quantum gravitational loop corrections may lead to a secular screening of the effective cosmological constant. Their argument rests upon a renormalization scheme in which the composite operator (Rsqrt(-g)-4Lambdasqrt(-g)) is ... [Phys. Rev. D 78, 028501 (2008)] published Tue Jul 22, 2008.

Resolution of curvature singularities in higher derivative gravity

Philipp Hoffer v. Loewenfeld and Ivo Sachs
We consider possible resolutions of singularities in a contracting anisotropic universe for a class of higher derivative gravity theories. We give evidence that for our models the big crunch singularity may be replaced by a nearly flat Minkowski-like phase before the Universe reenters an anisotropic ... [Phys. Rev. D 78, 024036 (2008)] published Tue Jul 22, 2008.

Dynamics in nonglobally hyperbolic, static space-times

Robert M. Wald
Ordinary Cauchy evolution determines a solution of a partial differential equation only within the domain of dependence of the initial data surface. Hence, in a nonglobally hyperbolic space-time, one does not have fully deterministic dynamics. We show here that for the case of a KleinGordon scalar f ... [J. Math. Phys. 21, 2802 (2008)] published Mon Jul 21, 2008.

Static gravitational and Maxwell fields in the general scalar tensor theory

A. Banerjee and S. B. Duttachoudhury
The expression for g as a function of the scalar field Psi is obtained in the general scalar tensor theory of gravitation proposed by Nordtvedt and later discussed by Barker, assuming that there exists a functional relationship between them. Exact solutions for a plane symmetric static gravitational ... [J. Math. Phys. 21, 2799 (2008)] published Mon Jul 21, 2008.

G[o-umlaut]del-like cosmological solutions

Dipankar Ray
Godels cosmological solutions have been generalized by Novello and Reboucas [Astrophys. J. 225, 71924 (1978)]. An attempt is made further to generalize their work. A class of solutions is obtained which are Godel-like in the sense of Novello and Reboucas, but which have singularities at both ends of ... [J. Math. Phys. 21, 2797 (2008)] published Mon Jul 21, 2008.

K-surfaces in the Schwarzschild space-time and the construction of lattice cosmologies

Dieter R. Brill, John M. Cavallo, and James A. Isenberg
We investigate spacelike spherically symmetric hypersurfaces of constant mean curvature K (which we call K-surfaces) in spherically symmetric static spacetimes. We obtain the differential equation satisfied by these surfaces from a variational principle. The spacetime Killing vector leads to a first ... [J. Math. Phys. 21, 2789 (2008)] published Mon Jul 21, 2008.

Relationships between the group-theoretic and soliton-theoretic techniques for generating stationary axisymmetric gravitational solutions

Christopher M. Cosgrove
We investigate the precise interrelationships between several recently developed solution-generating techniques capable of generating asymptotically flat gravitational solutions with arbitrary multipole parameters. The transformations we study in detail here are the Lie groups Q and Q-tilde of Cosgr ... [J. Math. Phys. 21, 2417 (2008)] published Mon Jul 21, 2008.

Properties of a covering space defined by Hawking

B. C. Haggman, G. W. Horndeski, and G. Mess
We investigate the topological properties of a covering space introduced by Hawking in 1967 to assist in his derivation of some singularity theorems. ... [J. Math. Phys. 21, 2412 (2008)] published Mon Jul 21, 2008.

Spatially homogeneous neutrino cosmologies

T. R. Michalik and M. A. Melvin
Gravitational effects of a c number neutrino field in spatially homogeneous geometries are analyzed. At the basis of the description of the geometries is an arbitrary timelike congruence with aligned tetrad reference frames, i.e., one basis vector of the tetrad frame at each point of spacetime is al ... [J. Math. Phys. 21, 1952 (2008)] published Mon Jul 21, 2008.

Symmetries and metrics of homogeneous cosmologies

M. A. Melvin and T. R. Michalik
It is shown that an assumption of ''historical homogeneity''or the persistence of spatial homogeneity in timeleads to the synchronous (time-orthogonal) form ds=dt+gamma (t)epsilon[direct-product]epsilon, of the metrics for general spatially homogeneous (Bianchi) cosmologies. The epsilon are group-re ... [J. Math. Phys. 21, 1938 (2008)] published Mon Jul 21, 2008.

A solution of the Cauchy initial value problem in the nonsymmetric theory of gravitation

J. W. Moffat
The Cauchy initial value problem in a theory of gravity based on a nonsymmetric Hermitian metric is investigated. The field equations are solved in terms of a series expansion of the metric g. In the nth order the equations take the form of either second-order hyperbolic partial differential equatio ... [J. Math. Phys. 21, 1798 (2008)] published Mon Jul 21, 2008.

Gravitational and electromagnetic potentials of the stationary Einstein--Maxwell field equations

Thaddeus C. Jones
We develop the necessary equations for the production of an infinite hierarchy of potentials for stationary EinsteinMaxwell spacetimes. Specific knowledge of these potentials are essential to the KinnersleyChitre method of solution generation. To elucidate their meaning we investigate the particular ... [J. Math. Phys. 21, 1790 (2008)] published Mon Jul 21, 2008.

The asymptotic behavior of the generalized Einstein--Maxwell field theory

Gregory Walter Horndeski
It is shown that the EinsteinMaxwell and generalized EinsteinMaxwell field theories essentially agree to first order at null and spatial infinity. ... [J. Math. Phys. 21, 1786 (2008)] published Mon Jul 21, 2008.

On the local simultaneity in general relativity

J. Olivert
In this paper the existence of simultaneous points, in the Landau sense, in the neighborhood of an observer P is studied. It is shown that the set of such points has the structure of a regular submanifold of the spacetime manifold. ... [J. Math. Phys. 21, 1783 (2008)] published Mon Jul 21, 2008.

The anholonomic Cauchy problem in general relativity

John Stachel
The Lie derivative approach to the Cauchy problem in general relativity is applied to the evolution along an arbitrary timelike vector field for the case where the dynamical degrees of freedom are chosen as the (generally anholonomic) metric of the hypersurface elements orthogonal to the vector fiel ... [J. Math. Phys. 21, 1776 (2008)] published Mon Jul 21, 2008.

Conformal coupling of gravitational wave field to curvature

L. P. Grishchuk and V.M. Yudin
Conformal properties of the equations for weak gravitational waves in a curved spacetime are investigated. The basic equations are derived in the linear approximation from Einstein's equations. They represent, in fact, the equations for the second-rank tensor field h, restricted by the auxiliary con ... [J. Math. Phys. 21, 1168 (2008)] published Mon Jul 21, 2008.

Spherically symmetric space--times with vanishing curvature scalar

Hubert Goenner and Peter Havas
A systematic study of spherically symmetric spacetimes with vanishing curvature scalar R is undertaken. The solutions of the equation R=0 are classified according to the number of different eigenvalues of the Ricci tensor R (which for spherical symmetry necessarily possesses one double eigenvalue) a ... [J. Math. Phys. 21, 1159 (2008)] published Mon Jul 21, 2008.

Aesthetic field theory; the problem of spatial inversions

M. Muraskin
In a previous paper we studied a set of origin point data that was invariant under three-dimensional rotations. This data, however, was not, in general, invariant under spatial inversions. We can obtain another set of data from the original data by performing a spatial inversion. Both sets of data c ... [J. Math. Phys. 21, 1155 (2008)] published Mon Jul 21, 2008.

Coordinate free relativity

Paul Carlson
A technique is presented using orthonormal tetrads which enables efficient algebraic manipulation of Einstein's equations by computer and ease of physical interpretation. The results are applied to the spherically symmetric case and Birkhoff's theorem is proved in the formalism. Several exact soluti ... [J. Math. Phys. 21, 1149 (2008)] published Mon Jul 21, 2008.

Symmetric vectors and algebraic classification

Elhanan Leibowitz
The concept of symmetric vector field in Riemannian manifolds, which arises in the study of relativistic cosmological models, is analyzed. Symmetric vectors are tied up with the algebraic properties of the manifold curvature. A procedure for generating a congruence of symmetric fields out of a given ... [J. Math. Phys. 21, 1141 (2008)] published Mon Jul 21, 2008.

A homogeneous Hilbert problem for the Kinnersley--Chitre transformations

Isidore Hauser and Frederick J. Ernst
A homogeneous Hilbert (Riemann) problem (HHP) is introduced for carrying out the KinnersleyChitre transformations of the set V of all axially symmetric stationary vacuum spacetimes, and the spacetimes which are like the axially symmetric stationary ones except that both Killing vectors are spacelike ... [J. Math. Phys. 21, 1126 (2008)] published Mon Jul 21, 2008.

The conformal geometry of Minkowski space: Hyperbolic world lines

A. J. Briginshaw
There is a discussion of (i) the transformation properties of hyperbolic hypersurfaces in Minkowski 4-space, (ii) the association of hyperbolic world lines in Minkowski 2-space with uniformly accelerated motion. ... [J. Math. Phys. 21, 878 (2008)] published Mon Jul 21, 2008.

A note on left-flat space--times

E. T. Newman and K. P. Tod
The theory of left-flat spacetimes is developed by introducing a null tetrad and imposing increasingly restrictive conditions on it. These conditions are justified from different points of view. In this way we present an elementary account of several of the different approaches to left-flat spaces. ... [J. Math. Phys. 21, 874 (2008)] published Mon Jul 21, 2008.

Curvatures of hypersurfaces of transitivity of Bianchi model universes

Alex Harvey
The Riemann curvatures of 2-surfaces are calculated for the spatial, 3-surfaces of transitivity of the various Bianchi models. It is found that some models are generally possessed simultaneously of both negative and positive curvature. The Bianchi V models are remarkable in that however large the de ... [J. Math. Phys. 21, 870 (2008)] published Mon Jul 21, 2008.

Electromagnetic test fields in the Kerr--Newman metric

S.K. Bose
The form of the electromagnetic test fields in the KerrNewman background, with the background metric held fixed, is closedly evaluated. ... [J. Math. Phys. 21, 868 (2008)] published Mon Jul 21, 2008.

Null infinity and Killing fields

Abhay Ashtekar and B. G. Schmidt
A recent investigation due to Ashtekar and Xanthopoulos of isometries compatible with asymptotic flatness at null infinity is extended by considering spacetimes which admit ''only a piece of [script J]. This extension makes the interplay between asymptotic conditions and permissible isometries more ... [J. Math. Phys. 21, 862 (2008)] published Mon Jul 21, 2008.

Equilibrium of slowly rotating relativistic fluids

H. P. Kunzle and J.R. Savage
The equilibrium conditions of a relativistic fluid with nonzero viscosity and heat conduction coefficients are known to reduce to Einstein's equations for a barotropic perfect fluid in rigid motion. We consider here the linearization of these equations on a static spherically symmetric background an ... [J. Math. Phys. 21, 347 (2008)] published Mon Jul 21, 2008.

Remarks on characteristic classes of four-dimensional Einstein manifolds

Y. L. Xin
Using the decomposition of the curvature tensor by means of the dual * operator, several useful expressions for characteristic classes in some kinds of Einstein manifolds are obtained. Consequently, some topological restrictions of the underlying manifolds are considered. ... [J. Math. Phys. 21, 343 (2008)] published Mon Jul 21, 2008.

Erratum: Characteristic surfaces and characteristic initial data for the generalized Einstein--Maxwell field equations [J. Math. Phys. [bold 2][bold 0], 1745(1979)].

Gregory Walter Horndeski
... [J. Math. Phys. 21, 218 (2008)] published Mon Jul 21, 2008.

Erratum: Note on the stability of the Schwarzschild metric [J. Math. Phys. [bold 2][bold 0], 1056(1979)].

Robert M. Wald
... [J. Math. Phys. 21, 218 (2008)] published Mon Jul 21, 2008.

On algebraically special space--times with nontwisting rays

Garry Ludwig
With the aid of the NewmanPenrose formalism and Penrose's conformal technique Einstein's gravitational field equations are first solved exactly as far as is possible for arbitrary sources. It is assumed, however, that spacetime is algebraically special with hypersurface-orthogonal geodesic and shear ... [J. Math. Phys. 21, 154 (2008)] published Mon Jul 21, 2008.

Dust cylinders in static space-times

J. D. Lathrop and M. S. Orsene
We argue that the work of Vishveshwara and Winicour suggests that there is an upper limit to the linear mass densities of infinite cylinders in static, cylindrically symmetric spacetimes. We investigate the class of static cylinders havong two oppositely directed circular flows of dust, and show tha ... [J. Math. Phys. 21, 152 (2008)] published Mon Jul 21, 2008.

Structure of the gravitational field at spatial infinity. II. Asymptotically Minkowskian space--times

S. Persides
A new formulation is established for the study of the asymptotic structure at spatial infinity of asymptotically Minkowskian spacetimes. First, the concept of an asymptotically simple spacetime at spatial infinity is defined. This is a (physical) spacetime ([script M],g) which can be imbedded in an ... [J. Math. Phys. 21, 142 (2008)] published Mon Jul 21, 2008.

Structure of the gravitational field at spatial infinity. I. Asymptotically Euclidean spaces

S. Persides
A new formulation for the study of the asymptotic structure of a gravitational field at spatial infinity is presented. First, the disadvantages of the existing formulations are identified in order to recognize the underlying causes and exclude them from the new formulation. It is concluded that neit ... [J. Math. Phys. 21, 135 (2008)] published Mon Jul 21, 2008.

Einstein spaces and homothetic motions. II

W. D. Halford
Algebraically special, nonflat vacuum Einstein spaces with an expanding and/or twisting geodesic principal null congruence are considered. These spaces are assumed to possess locally a homothetic symmetry as well as an isometry (one Killing vector). Nine metrics are obtained, six of which are twisti ... [J. Math. Phys. 21, 129 (2008)] published Mon Jul 21, 2008.

Einstein spaces and homothetic motions. I

W. D. Halford and R. P. Kerr
Algebraically special, nonflat vacuum Einstein spaces with an expanding and/or twisting geodesic principal null congruence are considered. These spaces are assumed to possess locally a homothetic symmetry as well as two or more Killing vectors. All metrics of such spaces are determined along with th ... [J. Math. Phys. 21, 120 (2008)] published Mon Jul 21, 2008.

Exact solutions of Brans--Dicke theory for irrotational barotropic models with stiff matter

V. B. Johri and G. K. Goswami
In the previous work, we have obtained classes of exact solutions of BransDicke (BD) theory when only a scalar field is present and also in the presence of an electromagnetic field. In the present paper, we have generated a new class of solutions of BD theory corresponding to irrotational barotropic ... [J. Math. Phys. 21, 2269 (2008)] published Mon Jul 21, 2008.

Some electrovac models of homogeneous gravitational force fields in general relativity

K. N. Srinivasa Rao and A. V. Gopala Rao
In this paper we consider the problem of defining and constructing the general relativistic analog of the Newtonian homogeneous gravitational force field. With this purpose, the Newtonian definition of homogeneity is first reformulated in a manner suitable for nonflat space sections and is then show ... [J. Math. Phys. 21, 2261 (2008)] published Mon Jul 21, 2008.

Kerr-like neutrino-gravitational solutions

Anthony W. -C. Lun
Two distinct stationary axisymmetric Kerr-like neutrino-gravitational spacetimes are presented. They reduce to the Kerr solution when the neutrino field vanishes. In addition, the first solution possesses physical line singularities along the axis of symmetry; whereas the second solution is asymptot ... [J. Math. Phys. 21, 2257 (2008)] published Mon Jul 21, 2008.

On the stationary Einstein--Maxwell field equations

A. Das and S. Kloster
The stationary gravitational equations in the presence of the electromagnetic fields, outside charged gravitating sources, are investigated. (i) The action integral of KramerNeugebauerStephani (K.N.S.) is derived from the Hilbert action integral by using new variational techniques. (ii) It is shown ... [J. Math. Phys. 21, 2248 (2008)] published Mon Jul 21, 2008.

A note on the good cut equation

Robert W. Lind
The good cut equation (F Z=sigma) is the link between a physical asymptotically flat spacetime (characterized by sigma) and its associated H-space (characterized by Z and interpreted by Penrose as a nonlinear graviton). In this work a class of regular, nontrivial (sigma[not-equal]0) solutions to the ... [J. Math. Phys. 21, 2245 (2008)] published Mon Jul 21, 2008.

On a new solution of Einstein's equations

C. Hoenselaers
An analysis of a stationary axisymmetric solution of Einstein's equations recently derived by Hoenselaers, Kinnersley, and Xanthopoulos is given. We derive the metric of the full spacetime, the invariants of the Weyl tensor, the first few multipole moments, and discuss the stationary limit surfaces ... [J. Math. Phys. 21, 2241 (2008)] published Mon Jul 21, 2008.

Canonical connections on Riemannian symmetric spaces and solutions to the Einstein--Yang--Mills equations

J. Harnad, J. Tafel, and S. Shnider
It is shown that for any principal bundle over a Riemannian symmetric space G/G which admits G as automorphism group, the canonical G-invariant connection satisfies the source free gauge field equations. Extending this to product manifolds V x G/G and assuming the metric and gauge fields decompose i ... [J. Math. Phys. 21, 2236 (2008)] published Mon Jul 21, 2008.

Symmetries of the stationary Einstein--Maxwell field equations. VII. Charging transformations

William Kinnersley
The group B of transformations which preserve asymptotic flatness is enlarged to include ''charging'', and other electromagnetic transformations. The new group B[prime] can be applied to the TomimatsuSato solution to produce an EinsteinMaxwell solution with nine free parameters. ... [J. Math. Phys. 21, 2231 (2008)] published Mon Jul 21, 2008.

Space-times with geodesic, shearfree, twistfree, nonexpanding rays

Garry Ludwig
The Kundt class of metrics containing geodesic rays with vanishing divergence, shear and curl is obtained for more general Ricci tensors using the standard NewmanPenrose formalism. These solutions are then rederived using Penrose's conformal technique, thereby clarifying their asymptotic behavior. ... [J. Math. Phys. 21, 2543 (2008)] published Mon Jul 21, 2008.

Asymptotic behavior of gravitational fields in a type II coordinate system

Garry Ludwig
With the aid of Penrose's conformal technique the asymptotic behavior of the components of the metric tensor, the Weyl tensor, the Ricci tensor and the spin-coefficients is calculated for a large class of space-times that includes the NUT (NewmanUntiTamburino) solution as well as all asymptotically ... [J. Math. Phys. 21, 2538 (2008)] published Mon Jul 21, 2008.

A factorization of M[sub 4]: Construction of the principal bundle of orthogonal frames over M[sub 4] from O(3,3) spinors

Patrick L. Nash
The principal bundle of orthogonal frames over M is explicitly constructed from certain pairs of O(-bar 3-bar,-bar 3-bar)-acute bar)= spinors that transform as (associated) twistors under the action of the covering group of the Poincare group. In particular, flat spacetime is constructed from these ... [J. Math. Phys. 21, 2534 (2008)] published Mon Jul 21, 2008.

Some properties of static general relativistic stellar models

Lee Lindblom
A number of properties of static general relativistic stellar models are presented which appear to be relevant to the ongoing search for a proof that all such models must have spherical symmetry. It is shown that any such model, having conformally flat spatial sections, must have spherical symmetry. ... [J. Math. Phys. 21, 1455 (2008)] published Mon Jul 21, 2008.

Einstein--Cartan theory in the spin coefficient formalism

R. Gambini and L. Herrera
The field equations of the EinsteinCartan theory are written down using the spin coefficient formalism developed by Newman and Penrose for the Einstein theory. The irreducible spinor decomposition of the Riemann tensor in a U space is obtained. ... [J. Math. Phys. 21, 1449 (2008)] published Mon Jul 21, 2008.

Matching of the plane symmetric static and homogeneous vacuum solutions of the Einstein field equations

George T. Carlson, Jr. and John L. Safko
The Taub plane symmetric static and homogeneous vacuum solutions are matched on a natural hypersurface. The spacetimes obtained in this way have distribution valued curvature tensors along the joining hypersurfaces. Our treatment of this problem follows Taub's presentation of spacetimes with distrib ... [J. Math. Phys. 21, 1442 (2008)] published Mon Jul 21, 2008.

Gauss--Bonnet and Bianchi identities in Riemann--Cartan type gravitational theories

H. T. Nieh
We present elementary derivations of the GaussBonnet type and Bianchi type identities for RiemannCartan geometry. The identities are derived directly in terms of the vierbein field e and the spin-connection field [script V], in the spirit of gauge theory, and are suitable for discussing RiemannCarta ... [J. Math. Phys. 21, 1439 (2008)] published Mon Jul 21, 2008.

Gravitation as an internal gauge theory of the Poincar[e-acute] group

C. P. Luehr and M. Rosenbaum P.
We describe a gauge theory of gravitation based on the poincare group treated as an internal symmetry group acting on five-dimensional fiber spaces. One special feature of the theory is that the metric structure of the manifold which serves as the base space appears as a natural consequence of the f ... [J. Math. Phys. 21, 1432 (2008)] published Mon Jul 21, 2008.

Space--times with distribution valued curvature tensors

A. H. Taub
A spacetime in which in an admissible coordinate system the metric tensor is continuous but has a finite jump in its first and second derivatives across a submanifold will have a curvature tensor containing a Dirac delta function. The support of this distribution may be of three, two, or one dimensi ... [J. Math. Phys. 21, 1423 (2008)] published Mon Jul 21, 2008.

A homogeneous Hilbert problem for the Kinnersley--Chitre transformations of electrovac space-times

Isidore Hauser and Frederick J. Ernst
The homogeneous Hilbert problem which we recently formulated for KinnersleyChitre transformations of vacuum spacetimes is here generalized to handle transformations of electrovac spacetimes. This provides in particular a simple derivation of our previously published integral equation. ... [J. Math. Phys. 21, 1418 (2008)] published Mon Jul 21, 2008.

On the role of space--time topology in quantum phenomena: Superselection of charge and emergence of nontrivial vacua

Abhay Ashtekar and Amitabha Sen
SchwarzschildKruskal spacetime admits a two-parameter family of everywhere regular, static, source-free Maxwell fields. It is shown that there exists a corresponding two-parameter family of unitarily inequivalent representations of the canonical commutation relations. Elements of the underlying Hilb ... [J. Math. Phys. 21, 526 (2008)] published Mon Jul 21, 2008.

Inhomogeneous rotating universes with closed timelike geodesics of matter

I.Damiao Soares
We present a new class of inhomogeneous stationary cosmological solutions of EinsteinMaxwell equations, with rotating dust and electromagnetic fields. For a subclass of these models, the topology of the spacetime manifold is S x R, and the timelike geodesic lines of dust are closed; electromagnetic ... [J. Math. Phys. 21, 521 (2008)] published Mon Jul 21, 2008.

Field equations in twistors

Asghar Qadir
As part of the twistor program for the ''quantization of relativity'' the physical field equations have been translated into twistors. ... [J. Math. Phys. 21, 514 (2008)] published Mon Jul 21, 2008.

Solar system constraints on the Dvali-Gabadadze-Porrati braneworld theory of gravity

James B. R. Battat, Christopher W. Stubbs, and John F. Chandler
A number of proposals have been put forward to account for the observed accelerating expansion of the Universe through modifications of gravity. One specific scenario, Dvali-Gabadadze-Porrati (DGP) gravity, gives rise to a potentially observable anomaly in the solar system: all planets would exhibit ... [Phys. Rev. D 78, 022003 (2008)] published Mon Jul 21, 2008.

Analytic model for the bispectrum of galaxies in redshift space

Robert E. Smith, Ravi K. Sheth, and Roman Scoccimarro
We develop an analytic theory for the redshift space bispectrum of dark matter, haloes, and galaxies. This is done within the context of the halo model of structure formation, as this allows for the self-consistent inclusion of linear and nonlinear redshift-space distortions and also for the nonline ... [Phys. Rev. D 78, 023523 (2008)] published Fri Jul 18, 2008.

Stationary rotating strings as relativistic particle mechanics

Kouji Ogawa, Hideki Ishihara, Hiroshi Kozaki, Hiroyuki Nakano, and Shinya Saito
Stationary rotating strings can be viewed as geodesic motions in appropriate metrics in two-dimensional space. We obtain all solutions describing stationary rotating strings in flat spacetime as an application. These rotating strings have infinite length with various wiggly shapes. Averaged value of ... [Phys. Rev. D 78, 023525 (2008)] published Fri Jul 18, 2008.

Model of dark matter and dark energy based on gravitational polarization

Luc Blanchet and Alexandre Le Tiec
A model of dark matter and dark energy based on the concept of gravitational polarization is investigated. We propose an action in standard general relativity for describing, at some effective or phenomenological level, the dynamics of a dipolar medium, i.e. one endowed with a dipole moment vector, ... [Phys. Rev. D 78, 024031 (2008)] published Fri Jul 18, 2008.

Torsion cosmology and the accelerating universe

Kun-Feng Shie, James M. Nester, and Hwei-Jang Yo
Investigations of the dynamic modes of the Poincare gauge theory of gravity found only two good propagating torsion modes; they are effectively a scalar and a pseudoscalar. Cosmology affords a natural situation where one might see observational effects of these modes. Here, we consider only the scal ... [Phys. Rev. D 78, 023522 (2008)] published Fri Jul 18, 2008.

Ray-tracing in four and higher dimensional black hole spacetimes: An analytical approximation

Patrick Connell and Valeri P. Frolov
We study null ray propagation in a spacetime of static SchwarzschildTangherlini black holes in an arbitrary number of dimensions. We focus on the bending angle and the retarded time delay for rays emitted in the vicinity of a black hole and propagating to the infinity. We obtain an analytic expressi ... [Phys. Rev. D 78, 024032 (2008)] published Fri Jul 18, 2008.

Spin-Foam Models and the Physical Scalar Product. (arXiv:0807.3561v1 [gr-qc])

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Geometry of a Centrosymmetric Electric Charge. (arXiv:0807.3618v1 [gr-qc])

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About the Minimal Resolution of Space-Time Grains in Experimental Quantum Gravity. (arXiv:0807.3619v1 [gr-qc])

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Nonrelativistic Dark-Energy Fluid in a Baby Universe. (arXiv:0807.3660v1 [gr-qc])

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Electromagnetic Induced Gravitational Perturbations. (arXiv:0807.3671v1 [gr-qc])

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The Field Structure of Vacuum, Maxwell Equations and Relativistic Theory Aspects. Part 1. (arXiv:0807.3691v2 [gr-qc])

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The solution of the cosmological constant problem from the inhomogeneous equation of state - a hint from modified gravity?. (arXiv:0807.3692v1 [gr-qc])

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Towards observable signatures of other bubble universes II: Exact solutions for thin-wall bubble collisions. (arXiv:0712.3038v4 [hep-th] UPDATED)

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Non-Relativistic Gravitation: From Newton to Einstein and Back. (arXiv:0712.4116v3 [hep-th] UPDATED)

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Time drift of cosmological redshifts as a test of the Copernican principle. (arXiv:0801.0068v2 [astro-ph] UPDATED)

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Schrodinger quantization of linearly polarized Gowdy $S^1\times S^2$ and $S^3$ models coupled to massless scalar fields. (arXiv:0802.3180v3 [gr-qc] UPDATED)

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Probes of Lorentz Violation in Neutrino Propagation. (arXiv:0805.0253v2 [hep-ph] UPDATED)

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