Extended minimal theories of massive gravity
Issued Date
2022-10-15
Resource Type
ISSN
24700010
eISSN
24700029
Scopus ID
2-s2.0-85141573301
Journal Title
Physical Review D
Volume
106
Issue
8
Rights Holder(s)
SCOPUS
Bibliographic Citation
Physical Review D Vol.106 No.8 (2022)
Suggested Citation
De Felice A., Mukohyama S., Pookkillath M.C. Extended minimal theories of massive gravity. Physical Review D Vol.106 No.8 (2022). doi:10.1103/PhysRevD.106.084050 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/86912
Title
Extended minimal theories of massive gravity
Author(s)
Author's Affiliation
Other Contributor(s)
Abstract
In this work, we introduce a class of extended minimal theories of massive gravity, without requiring a priori that the theory should admit the same homogeneous and isotropic cosmological solutions as the de Rham-Gabadadze-Tolley massive gravity. The theory is constructed as to have only two degrees of freedom in the gravity sector. In order to perform this step we first introduce a precursor theory endowed with a general graviton mass term, to which, at the level of the Hamiltonian, we add two extra constraints as to remove the unwanted degrees of freedom, which otherwise would typically lead to ghosts and/or instabilities. On analyzing the number of independent constraints and the properties of tensor mode perturbations, we see that the gravitational waves are the only propagating gravitational degrees of freedom which do acquire a nontrivial mass, as expected. In order to understand how the effective gravitational force works for this theory we then investigate cosmological scalar perturbations in the presence of a pressureless fluid. We then restrict the whole class of models by imposing the following conditions at all times: (1) it is possible to define an effective gravitational constant, Geff; (2) the value Geff/GN is always finite but not always equal to unity (as to allow some nontrivial modifications of gravity, besides the massive tensorial modes); and (3) the square of mass of the graviton is always positive. These constraints automatically make also the ISW-effect contributions finite at all times. Finally we focus on a simple subclass of such theories, and show they already can give a rich and interesting phenomenology.