Wave Operators, Torsion, and Weitzenböck Identities

Barrientos, José Vicente Rosas; Izaurieta, Fernando; Rodríguez, Eduardo; Valdivia, Omar

doi:10.48550/arxiv.1903.04712

Cited by 5 publications

(21 citation statements)

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“…The eikonal approximation is used to show that the new torsional mode (variously called "torsionon" [76], "roton" [77], or "gravity W and Z bosons" [78]) propagates interacting with the polarization of the standard metric mode, generalizing the results of Ref. [69]. Finally, conclusions and further comments are given in Sec.…”

Section: Introductionmentioning

confidence: 82%

“…The differential operators we define appeared originally in Refs. [51,69,76]; here we briefly review them for the benefit of the reader who may be unfamiliar with them. We also show that these operators form a superalgebra and identify its associated super-Jacobi identity, which, beyond the merely aesthetic, eases the study of the eikonal limit of GWs on an RC geometry.…”

Section: A a Superalgebra Of Differential Operatorsmentioning

confidence: 99%

“…Replacing these inhomogeneous terms and using the generalized Weitzenböck identity of Lemma 9 (see also Ref. [69]), W m can be written in terms of the generalized de Rham-Laplace wave operator (cf. Definition 7) as…”

Section: The Dispersion Relation Speed and Polarization Of Gravitatio...mentioning

confidence: 99%

“…This implies that the analysis of Ref. [69] has to be generalized to include the extra inhomogeneous terms in Eq. (111).…”

Section: The Dispersion Relation Speed and Polarization Of Gravitatio...mentioning

confidence: 99%

“…This does not mean, however, that torsion is wholly undetectable; as shown in Ref. [69], torsion affects the propagation of polarization for GWs. 1 Thus, at least for this case, the recent observational data only disfavor the torsionless version of the theory, but not its more general torsional relative.…”

Section: Introductionmentioning

confidence: 98%

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Luminal propagation of gravitational waves in scalar-tensor theories: The case for torsion

et al. 2019

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Scalar-tensor gravity theories with a nonminimal Gauss-Bonnet coupling typically lead to an anomalous propagation speed for gravitational waves, and have therefore been tightly constrained by multimessenger observations such as GW170817/GRB170817A. In this paper we show that this is not a general feature of scalar-tensor theories, but rather a consequence of assuming that spacetime torsion vanishes identically. At least for the case of a nonminimal Gauss-Bonnet coupling, removing the torsionless condition restores the canonical dispersion relation and therefore the correct propagation speed for gravitational waves. To achieve this result we develop a new approach, based on the first-order formulation of gravity, to deal with perturbations on these Riemann-Cartan geometries.topological invariants, e.g., the Pontryagin or Gauss-Bonnet (GB) terms, motivated by effective field theories, string theory, and particle physics [15]. From a phenomenological viewpoint, the scalar-Pontryagin modification to GR-also known as Chern-Simons modified gravity-is an interesting extension that might explain the flat galaxy rotation curves dispensing with dark matter [16], while leaving the propagation speed of GWs unaffected [17]. This interaction generates nontrivial effects when rotation is included [18][19][20][21][22][23], providing a smoking gun in future GW detectors [24][25][26][27]. The couplings between scalar fields and the GB term, on the other hand, have been studied in different setups and several solutions that exhibit spontaneous scalarization have been reported [28][29][30][31][32][33][34][35][36][37][38][39][40][41]. Their stability, however, depends on the choice of the coupling between the scalar field and the GB term [42][43][44]. In spite of this, the theory is experimentally disadvantaged from an astrophysical viewpoint, since it develops an anomalous propagation speed for GWs [45].Scalar-tensor theories have been formulated in geometries that depart from the pseudo-Riemannian framework several times in the past. In particular, the gravitational role of Riemann-Cartan (RC) geometries, characterized by curvature and torsion, was first discussed by Cartan and Einstein themselves [46], and later on in the framework of gauge theories of gravitation [47][48][49][50]. Within its simplest formulation-the Einstein-Cartan-Sciama-Kibble (ECSK) theory-torsion is a nonpropagating field sourced only by the spin density of matter. The nonminimal coupling of scalar fields to geometry dramati-arXiv:1910.00148v3 [gr-qc]

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Section: Introductionmentioning

confidence: 82%

Section: A a Superalgebra Of Differential Operatorsmentioning

confidence: 99%

Section: The Dispersion Relation Speed and Polarization Of Gravitatio...mentioning

confidence: 99%

“…This implies that the analysis of Ref. [69] has to be generalized to include the extra inhomogeneous terms in Eq. (111).…”

Section: The Dispersion Relation Speed and Polarization Of Gravitatio...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

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Luminal propagation of gravitational waves in scalar-tensor theories: The case for torsion

et al. 2019

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Scalar and fermion field interactions with a gravitational wave

Morales

Dasgupta

2020

Class. Quantum Grav.

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Given that gravity waves are the future probes of the universe, it is important to test various physical effects of these on matter. This article studies a perturbation of the field of a massless scalar particle caused by a gravity wave. We also discuss the gravitational waves' effect on a chiral fermion. Our results have physical implications for early universe cosmology and also for ground based observations.

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