Biswas, Tirthabir and Conroy, Aindriú and S. Koshelev, Alexey and Mazumdar, Anupam (2014) Generalized ghost-free quadratic curvature gravity. Classical and Quantum Gravity, 31 (15). ISSN 0264-9381
Full text not available from this repository.Abstract
In this paper we study the most general covariant action of gravity up to terms that are quadratic in curvature. In particular this includes non-local, infinite derivative theories of gravity which are ghost-free and exhibit asymptotic freedom in the ultraviolet. We provide a detailed algorithm for deriving the equations of motion for such actions containing an arbitrary number of the covariant D'Alembertian operators, and this is our main result. We also perform a number of tests on the field equations we derive, including checking the Bianchi identities and the weak-field limit. Lastly, we consider the special subclass of ghost and asymptotically free theories of gravity by way of an example.