Nonperturbative gravitomagnetic fields

Sopuerta, Carlos F.; Maartens, Roy; Ellis, George; Lesame, William M.

doi:10.1103/physrevd.60.024006

Cited by 22 publications

(51 citation statements)

References 21 publications

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“…This is a reflection of the integrability conditions discussed in [23], which suggests that div H a = 0 may not be as restrictive in perturbative models as it is in the fully non-linear case. The second order tensor modes, on the other hand, are covariantly characterised by div Σ a = 0, for which we have the genuine wave equation:…”

Section: The Induced Tensor Modesmentioning

confidence: 99%

“…By taking various spatial gradients of these eight variables it can be shown that there are some (differential) constraints which must be satisfied amongst these variables, which serve to constrain initial data, but we shall not pursue this further here (see [23] for details of where these come from). Note that we have managed to deal with all the complicated scalar-scalar coupling without recourse to harmonics.…”

Section: A Gravity Waves From Density Fluctuationsmentioning

confidence: 99%

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Publisher's Note: Cosmological density fluctuations and gravity waves: A covariant approach to gauge-invariant nonlinear perturbation theory [Phys. Rev. D70, 103524 (2004)]

Clarkson¹

2004

Phys. Rev. D

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We present a new approach to gauge-invariant cosmological perturbations at second order, which is also covariant. We examine two cases in particular for a dust Friedman-Lemaître-RobertsonWalker model of any curvature: we investigate gravity waves generated from clustering matter, that is, induced tensor modes from scalar modes; and we discuss the generation of density fluctuations induced by gravity waves -scalar modes from tensor perturbations. We derive a linear system of evolution equations for second-order gauge-invariant variables which characterise fully the induced modes of interest, with a source formed from variables quadratic in first-order quantities; these we transform into fully-fledged second-order gauge-invariant variables. Both the invariantly defined variables and the key evolution equations are considerably simpler than similar gauge-invariant results derived by other methods. By finding analytical solutions, we demonstrate that non-linear effects can significantly amplify or dampen modes present in standard linearised cosmological perturbation theory, thereby providing an important source of potential error in, and refinement of, the standard model. Moreover, these effects can dominate at late times, and on super-Hubble scales.

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Section: The Induced Tensor Modesmentioning

confidence: 99%

Section: A Gravity Waves From Density Fluctuationsmentioning

confidence: 99%

Publisher's Note: Cosmological density fluctuations and gravity waves: A covariant approach to gauge-invariant nonlinear perturbation theory [Phys. Rev. D70, 103524 (2004)]

Clarkson¹

2004

Phys. Rev. D

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“…In [22] (see also [23]), it was shown that a sufficient condition for this is H ab = 0, and in [24] this result was extended to the case in which H ab is transverse, i.e. div(H) a = 0.…”

Section: Formulation Of the Long Wave-length Approximation Scheme: Thmentioning

confidence: 99%

Covariant fluid dynamics: a long wavelength approximation

Bruni

Sopuerta

2003

Class. Quantum Grav.

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Abstract. In this paper we consider the Long-Wavelength Approximation Scheme (LWAS) in the framework of the covariant fluid approach to general relativistic dynamics, specializing to the particular case of irrotational dust matter. We discuss the dynamics of these models during the approach to any spacelike singularity where a BKL-type evolution is expected, studying the validity of this approximation scheme and the role of the magnetic part of the Weyl tensor, H ab . Our analytic results confirm a previous numerical analysis: it is H ab that destroys the pure Kasner-like approach to the singularity and eventually produces the bounce to another Kasner phase. Expanding regions evolve as separate universes where inhomogeneities and anisotropies die away.

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“…And from the constraint (14), we deduce that this is equivalent to the vanishing of the spatial divergence of the gravito-magnetic field (see, e.g., [8,9,10])…”

Section: Covariant Approachmentioning

confidence: 99%

“…IDMs with a divergence-free gravito-magnetic field have been studied in [9,10]. In these works the consistency of the new constraints (20,21) under evolution was studied.…”

Section: Covariant Approachmentioning

confidence: 99%

Cosmological models with flat spatial geometry

Sopuerta¹

2000

Class. Quantum Grav.

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Abstract. The imposition of symmetries or special geometric properties on submanifolds is less restrictive than to impose them in the full space-time. Starting from this idea, in this paper we study irrotational dust cosmological models in which the geometry of the hypersurfaces generated by the fluid velocity is flat, which supposes a relaxation of the restrictions imposed by the Cosmological Principle. The method of study combines covariant and tetrad methods that exploits the geometrical and physical properties of these models. This procedure will allow us to determine all the space-times within this class as well as to study their properties. Some important consequences and applications of this study are also discussed.

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Nonperturbative gravitomagnetic fields

Cited by 22 publications

References 21 publications

Publisher's Note: Cosmological density fluctuations and gravity waves: A covariant approach to gauge-invariant nonlinear perturbation theory [Phys. Rev. D70, 103524 (2004)]

Publisher's Note: Cosmological density fluctuations and gravity waves: A covariant approach to gauge-invariant nonlinear perturbation theory [Phys. Rev. D70, 103524 (2004)]

Covariant fluid dynamics: a long wavelength approximation

Cosmological models with flat spatial geometry

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