Infinite Derivative Gravity: A Ghost and Singularity-free Theory

@article{Conroy2017InfiniteDG,
  title={Infinite Derivative Gravity: A Ghost and Singularity-free Theory},
  author={Aindri'u Conroy},
  journal={arXiv: General Relativity and Quantum Cosmology},
  year={2017}
}
  • Aindri'u Conroy
  • Published 24 April 2017
  • Physics
  • arXiv: General Relativity and Quantum Cosmology
The objective of this thesis is to present a viable extension of general relativity free from cosmological singularities. A viable cosmology, in this sense, is one that is free from ghosts, tachyons or exotic matter, while staying true to the theoretical foundations of General Relativity such as general covariance, as well as observed phenomenon such as the accelerated expansion of the universe and inflationary behaviour at later times. To this end, an infinite derivative extension of… 

Figures from this paper

Infinite Derivative Gravity: A finite number of predictions

Ghost-free Infinite Derivative Gravity (IDG) is a modifed gravity theory which can avoid the singularities predicted by General Relativity. This thesis examines the effect of IDG on four areas of

On aspects of infinite derivatives field theories & infinite derivative gravity

Infinite derivative theory of gravity is a modification to the general theory of relativity. Such modification maintains the massless graviton as the only true physical degree of freedom and avoids

Criteria for resolving the cosmological singularity in Infinite Derivative Gravity

Einstein's General theory of relativity permits space-time singularities, where null congruences \emph{focus} in the presence of matter, which satisfies an appropriate energy condition. In this

Revealing infinite derivative gravity’s true potential: The weak-field limit around de Sitter backgrounds

General Relativity is known to produce singularities in the potential generated by a point source. Our universe can be modelled as a de Sitter (dS) metric and we show that ghost-free Infinite

Conditions for defocusing around more general metrics in Infinite Derivative Gravity

Infinite Derivative Gravity is able to resolve the Big Bang curvature singularity present in general relativity by using a simplifying ansatz. We show that it can also avoid the Hawking- Penrose

Testing gravity in the local universe

General relativity (GR) has stood as the most accurate description of gravity for the last 100 years, weathering a barrage of rigorous tests. However, attempts to derive GR from a more fundamental

Gravitational radiation in infinite derivative gravity and connections to effective quantum gravity

The Hulse-Taylor binary provides possibly the best test of GR to date. We find the modified quadrupole formula for infinite derivative gravity (IDG). We investigate the backreaction formula for

Pushing the limits of time beyond the Big Bang singularity: The branch cut universe

In this article we follow a previously developed theoretical approach, based in the tools of the singular semi-Riemannian geometry, to push the limits of time beyond the primordial spacetime

Local and Nonlocal Thermal Field Theory

Firstly, nonlocal field theories will be motivated, primarily in the gravity sector. We discuss how nonlocal theories of gravity can circumvent typical problems of finitely-many higher derivative

Parity-violating gravity and GW170817 in non-Riemannian cosmology

The cosmological propagation of tensor perturbations is studied in the context of parity-violating extensions of the symmetric teleparallel equivalent of General Relativity theory. This

References

SHOWING 1-10 OF 120 REFERENCES

Defocusing of null rays in infinite derivative gravity

Einstein's General theory of relativity permits spacetime singularities, where null geodesic congruences focus in the presence of matter, which satisfies an appropriate energy condition. In this

Towards a resolution of the cosmological singularity in non-local higher derivative theories of gravity

One of the greatest problems of standard cosmology is the Big Bang singularity. Previously it has been shown that non-local ghostfree higher-derivative modifications of Einstein gravity in the

Towards understanding the ultraviolet behavior of quantum loops in infinite-derivative theories of gravity

In this paper we will consider quantum aspects of a non-local, infinite-derivative scalar field theory—a toy model depiction of a covariant infinite-derivative, non-local extension of Einstein’s

Hamiltonian Analysis for Infinite Derivative Field Theories and Gravity

Typically higher-derivative theories are unstable. Instabilities manifest themselves from extra propagating degrees of freedom, which are unphysical. In this paper, we will investigate an infinite

Nonlocal gravity in D dimensions: Propagators, entropy, and a bouncing cosmology

We present the graviton propagator for an infinite derivative, D-dimensional, nonlocal action, up to quadratic order in curvature around a Minkowski background, and discuss the conditions required

Generalized quadratic curvature, non-local infrared modifications of gravity and Newtonian potentials

Metric theories of gravity are studied, beginning with a general action that is quadratic in curvature and allows arbitrary inverse powers of the dʼAlembertian operator, resulting in infrared

Super-accelerating bouncing cosmology in asymptotically free non-local gravity

Recently, evidence has been collected that a class of gravitational theories with certain non-local operators is renormalizable. We consider one such model which, at the linear perturbative level,

Fourth order gravity: Equations, history, and applications to cosmology

The field equations following from a Lagrangian L(R) will be deduced and solved for special cases. If L is a non-linear function of the curvature scalar, then these equations are of fourth order in

Consistent Higher Derivative Gravitational theories with stable de Sitter and Anti-de Sitter Backgrounds

In this paper we provide the criteria for any generally covariant, parity preserving, and torsion-free theory of gravity to possess a stable de Sitter (dS) or anti-de Sitter (AdS) background. By

Behavior of the Newtonian potential for ghost-free gravity and singularity free gravity

In this paper we show that there is a universal prediction for the Newtonian potential for an infinite derivative, ghost-free, quadratic curvature gravity. We show that in order to make such a theory
...