Does space-time torsion determine the minimum mass of gravitating particles?

Böhmer, Christian G.; Burikham, Piyabut; Harkó, Tiberiu; Lake, Matthew J.

doi:10.1140/epjc/s10052-018-5719-y

Cited by 8 publications

(5 citation statements)

References 116 publications

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“…The mass -radius relations, as well as the possible existence of a minimum mass have been in different theoretical contexts, and for different physical models, in [56][57][58][59][60][61]. The generalized Buchdahl inequalities in arbitrary space-time dimensions in the presence of a non-zero cosmological constant were obtained in [56], by considering both the de Sitter and anti-de Sitter cases.…”

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confidence: 99%

“…The existence of the lower mass bound is induced by the presence of the effective cosmological constant, which produces a mass gap, while the upper bound corresponds to a deconfinement phase transition. Upper and lower limits for the mass-radius ratio of spin-fluid spheres in Einstein-Cartan theory in the presence of a cosmological constant were considered in [61], under the assumption that matter satisfies a linear barotropic equation of state. In the case of the spingeneralized strong gravity model for baryons/mesons, show the existence of quantum spin imposes a lower mass bound for spinning particles, which almost exactly reproduces the electron mass.…”

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Mass-radius ratio bounds for compact objects in Lorentz-violating dRGT massive gravity theory

2018

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We consider the mass-radius bounds for spherically symmetric static compact objects in the de Rham-Gabadadze-Tolley (dRGT) Massive Gravity theories, free of ghosts. In this type of gravitational theories the graviton, the quantum of gravity, may have a small, but non-vanishing mass. We derive the hydrostatic equilibrium and mass continuity equations in the Lorentz-violating Massive gravity in the presence of a cosmological constant and for a non-zero graviton mass. The case of the constant density stars is also investigated by numerically solving the equilibrium equations. The influence of the graviton mass on the global parameters (mass and radius) of these stellar configurations is also considered. The generalized Buchdahl relations, giving the upper and lower bounds of the mass-radius ratio are obtained, and discussed in detail. As an application of our results we obtain gravitational redshift bounds for compact stellar type objects in the Lorentz-violating dRGT Massive Gravity, which may (at least in principle) be used for observationally testing this theory in an astrophysical context.

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confidence: 99%

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Mass-radius ratio bounds for compact objects in Lorentz-violating dRGT massive gravity theory

2018

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“…Two important particular cases that are widely used in the physics literature and verify the conditions in Theorem 1 are: Torsion tensors of the form S αβ σ = S αβ v σ (see e.g. [6,17,24,25,26] and references therein); Torsion tensors completely anti-symmetric S αβσ = S [αβσ] , where A α = 0 and W αβ = W [αβ] = −2S αβ (see e.g. [27,28,29]).…”

Section: Focusing Of Time-like Congruencesmentioning

confidence: 99%

Singularity theorems and the inclusion of torsion in affine theories of gravity

Luz

Mena

2020

Journal of Mathematical Physics

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We extend the scope of the Raychaudhuri-Komar singularity theorem of General Relativity to affine theories of gravity with and without torsion. We first generalize the existing focusing theorems using time-like and null congruences of curves which are hypersurface orthogonal, showing how the presence of torsion affects the formation of focal points in Lorentzian manifolds. Considering the energy conservation on a given affine gravity theory, we prove new singularity theorems for accelerated curves in the cases of Lorentzian manifolds containing perfect fluids or scalar field matter sources.1 In this article, we will make no distinction between focal or conjugate points, see e.g. [4] for the precise definitions. a space-time singularity, in the sense that the geodesics of the congruence were inextensible beyond that point.After the initial works of Hawking and Penrose, many extensions and reformulations to their singularity theorems have been made (see e.g. [4,5] for a review in the context of space-times without torsion). In particular, since the 1970's there was a growing interest in studying whether the inclusion of space-time torsion could prevent the formation of singularities [6,7,8]. This led to the formulation of singularity theorems for space-times with torsion [14,30]. Indeed, using the incompleteness of time-like metric geodesics to probe the regularity of space-times in the Einstein-Cartan theory of gravity, Hehl et al. [17] found that the original Hawking-Penrose singularity theorems were equally valid in that theory, with the correction that the matter constraints had to be imposed on a modified stress-energy tensor. More recently, [22] related the occurrence of singularities with the existence of horizons, and formulated singularity theorems of Hawking-Penrose type for non-geodesic curves in particular Teleparallel and Einstein-Cartan theories of gravity.In this paper, we consider the more general setting of affine theories of gravity with a nonsymmetric affine connection, compatible with the metric. Our main questions are: What are the new geometric necessary conditions for the existence of focal points? How can we generalize the focusing theorems to any causal curves, not necessarily geodesics, in Lorentzian manifolds with torsion? In which cases can we prove singularity theorems from the focusing theorems, without imposing any further constrains on the manifold?In order to answer those questions, we need to include general torsion terms in the structure equations of Lorentzian manifolds and carefully analyze the new terms. We will rely on the assumption that a hypersurface orthogonal congruence of curves exists. So, first, in Section 2.1, we establish conditions for the existence of such congruences based on Frobenius theorem. Then, in sections 2.2 and 2.3, we prove new results for the focusing of time-like and null, hypersurface orthogonal congruences.Although a necessary step towards the proof of the classical singularity theorems, those focusing results are not sufficient to prove singularity ...

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“…In the first case, it has been proved that spin interactions in the early stages of the universe could bring about significant results, such as the avoidance of the big-bang singularity, as well as the reproduction of cosmic inflation and dark energy mechanisms [69][70][71][72]. In astrophysical settings, the spin may avert the spacetime singularity caused by the gravitational collapse of a star [73][74][75][76][77].…”

Section: Introductionmentioning

confidence: 99%

Gravitational waves at the first post-Newtonian order with the Weyssenhoff fluid in Einstein-Cartan theory

Battista,

De Falco

2022

Preprint

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The generation of gravitational waves from a post-Newtonian source endowed with a quantum spin, modeled by the Weyssenhoff fluid, is investigated in the context of Einstein-Cartan theory at the first post-Newtonian level by resorting to the Blanchet-Damour formalism. After having worked out the basic principles of the hydrodynamics in Einstein-Cartan framework, we study the Weyssenhoff fluid within the post-Newtonian approximation scheme. The complexity of the underlying dynamical equations suggests to employ a discrete description via the point-particle limit, a procedure which permits the analysis of inspiralling spinning compact binaries. We then provide a first application of our results by considering binary neutron star systems.

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Does space-time torsion determine the minimum mass of gravitating particles?

Cited by 8 publications

References 116 publications

Mass-radius ratio bounds for compact objects in Lorentz-violating dRGT massive gravity theory

Mass-radius ratio bounds for compact objects in Lorentz-violating dRGT massive gravity theory

Singularity theorems and the inclusion of torsion in affine theories of gravity

Gravitational waves at the first post-Newtonian order with the Weyssenhoff fluid in Einstein-Cartan theory

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