Stability and (quasi)localization of gravitational fluctuations in an Eddington-inspired Born-Infeld brane system

Abstract

The stability and localization of the gravitational perturbations for a special brane system in Eddingtoninspired Born-Infeld gravity were studied in Liu et al. [Phys. Rev. D 85, 124053 (2012)]. In this paper, we show that the gravitational perturbations for a general brane system are stable, the four-dimensional graviton (massless KK graviton) can be localized on the brane, and the mass spectra of massive KK gravitons are gapless and continuous. Two models are constructed as examples. In the first model, which is a generalization of Liu et al. [Phys. Rev. D 85, 124053 (2012)], the brane has no inner structure and there is no gravitational resonance (quasilocalized KK gravitons). In the second one, the background scalar field is a double kink when the parameter in the model approaches its critical value. Correspondingly, the brane has inner structure and some gravitational resonances appear.

Constraint on dark matter central density in the Eddington inspired Born-Infeld (EiBI) gravity with input from Weyl gravity

“…Stability and localization of gravitational fluctuations in the EiBI brane system have been studied in Refs. [86,87]. Further, as shown by Wei et al [88], strong gravitational lensing observables in EiBI are controlled by the coupling parameter κ, which is a new prediction that lends itself to future testing.…”

Born–Infeld inspired modifications of gravity

“…The effective potential (4.177) has a (asymptotically vanishing) volcano-like profile with a well at the center of the kink, with the result that a continuous set of massive Kaluza-Klein modes (not localized on the brane) arises for p > 0. The above study was further generalized by Fu et al [172], where they considered a class of solutions defined by the ansatz φ ′ (y) = Ka(y) 2n , so that Liu et al case [242] corresponds just to n = 1. The corresponding solutions for the warp factor and the scalar field can also be obtained in closed analytical form as a(y) = sech 3 4n (ky) ; φ(y) = 2K k iE(iky/2, 2)sech 1/2 (ky) sinh(ky) (4.179) where the constants…”

Scalar perturbation produced at the pre-inflationary stage in Eddington-inspired Born–Infeld gravity

“…Other than inflation, EiBI gravity has presented interesting cosmological and astrophysical results investigated in Refs. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. From the gravity theory point of view, the unitarity problem related with the ghost graviton mode of the theory is an important issue.…”