Massive higher derivative gravity theories

Güllü, İbrahim
In this thesis massive higher derivative gravity theories are analyzed in some detail. One-particle scattering amplitude between two covariantly conserved sources mediated by a graviton exchange is found at tree-level in D dimensional (Anti)-de Sitter and flat spacetimes for the most general quadratic curvature theory augmented with the Pauli-Fierz mass term. From the amplitude expression, the Newtonian potential energies are calculated for various cases. Also, from this amplitude and the propagator structure, a three dimensional unitary theory is identified. In the second part of the thesis, the found three dimensional unitary theory is studied in more detail from a canonical point of view. The general higher order action is written in terms of gauge-invariant functions both in flat and de Sitter backgrounds. The analysis is extended by adding static sources, spinning masses and the gravitational Chern-Simons term separately to the theory in the case of flat spacetime. For all cases the microscopic spectrum and the masses are found. In the discussion of curved spacetime, the masses are found in the relativistic and non-relativistic limits. In the Appendix, some useful calculations that are frequently used in the bulk of the thesis are given.


Gravitating instantons in 3 dimensions
Ferstl, A; Tekin, Bayram; Weir, V (2000-09-15)
We study the Einstein-Chern-Simons gravity coupled to Yang-Mills-Higgs theory in three-dimensional Euclidean space with a cosmological constant. The classical equations reduce to Bogomol'nyi type first order equations in curved space. There are BPS type gauge theory instanton (monopole) solutions of finite action in a gravitational instanton which itself has a finite action. We also discuss gauge theory instantons in the vacuum (zero action) AdS space. In addition we point out to some exact solutions which ...
Particle content of quadratic and f (R-mu nu sigma rho) theories in (A)dS
Tekin, Bayram (2016-05-17)
We perform a complete decoupling of the degrees of freedom of quadratic gravity and the generic f(R-mu nu sigma rho) theory about any one of their possible vacua, i.e. maximally symmetric solutions, and find the masses of the spin-2 and spin-0 modes in explicit forms.
Problems of Massive Gravity
Boybeyi, Töre Deniz; Tekin, Bayram; Department of Physics (2021-8-5)
In this thesis, the general properties of massive gravitation theories are outlined. Particular attention is given to the van Dam-Veltman-Zakharov discontinuity which arises in the massless limit of massive theories. Also, the observational, holographic, and thermodynamic properties of these theories are mentioned.
Weyl-invariant higher curvature gravity theories
Dengiz, Suat; Tekin, Bayram; Department of Physics (2014)
In this thesis, Weyl-invariant extensions of three-dimensional New Massive Gravity, generic n-dimensional Higher Curvature Gravity theories and three-dimensional Born-Infeld gravity theory are analyzed in details. As required by Weyl-invariance, the actions of these gauge theories do not contain any dimensionful parameter, hence the local symmetry is spontaneously broken in (Anti) de Sitter vacua in analogy with the Standard Model Higgs mechanism. In flat vacuum, symmetry breaking mechanism is more complica...
Bachian gravity in three dimensions
Tek, Mustafa; Tekin, Bayram; Department of Physics (2019)
Modified theories in 3-dimensions such as the topologically massive gravity (TMG), new massive gravity (NMG) or Born-Infeld extension of NMG arise from the vari-ations of diffeomorphism invariant actions; hence the resulting field equations aredivergence free. Namely, the rank two tensor defining the field equations satisfy aBianchi identity for all smooth metrics. However there are some recently constructedtheories that do not identically satisfy Bianchi identities for all metrics, but only forthe soluti...
Citation Formats
İ. Güllü, “Massive higher derivative gravity theories,” Ph.D. - Doctoral Program, Middle East Technical University, 2011.