Charged black holes in the infinite derivative theory of gravity

The infinite derivative theory of gravity is a generalization of Einstein gravity with many interesting properties, but the black hole solutions in this theory are still not fully understood. In the paper, we concentrate on studying the charged black holes in such a theory. Adding the electromagnetic field part to the effective action, we show how the black hole solutions around the Reissner-Nordstr{\"o}m metric can be solved perturbatively and iteratively. We further calculate the corresponding temperature, entropy and electrostatic potential of the black holes and verify the first law of thermodynamics.

High $$P_T$$ Higgs excess as a signal of non-local QFT at the LHC

Non-local extensions of the Standard Model with a non-locality scale $$\varLambda _{NL}$$ Λ NL have the effect of smearing the pointlike vertices of the Standard Model. At energies significantly lower than $$\varLambda _{NL}$$ Λ NL vertices appear pointlike, while beyond this scale all beta functions vanish and all couplings approach a fixed point leading to scale invariance. Non-local SM extensions are ghost free, with the non-locality scale serving as an effective cutoff to radiative corrections of the Higgs mass. We argue that the data expected to be collected at the LHC phase 2 will have a sensitivity to non-local effects originating from a non-locality scale of a few TeV. Using an infinite derivative prescription, we study modifications to heavy vector-boson cross sections that can lead to an enhanced production of boosted Higgs bosons in a region of the kinematic phase space where the SM background is very small.

Ghost-free higher-order theories of gravity with torsion

In this manuscript we will present the theoretical framework of the recently proposed infinite derivative theory of gravity with a non-symmetric connection. We will explicitly derive the field equations at the linear level and obtain new solutions with a non-trivial form of the torsion tensor in the presence of a fermionic source, and show that these solutions are both ghost and singularity-free.

Graviton-mediated scattering amplitudes from the quantum effective action

We employ the curvature expansion of the quantum effective action for gravity-matter systems to construct graviton-mediated scattering amplitudes for non-minimally coupled scalar fields in a Minkowski background. By design, the formalism parameterises all quantum corrections to these processes and is manifestly gauge-invariant. The conditions resulting from UV-finiteness, unitarity, and causality are analysed in detail and it is shown by explicit construction that the quantum effective action provides sufficient room to meet these structural requirements without introducing non-localities or higher-spin degrees of freedom. Our framework provides a bottom-up approach to all quantum gravity programs seeking for the quantisation of gravity within the framework of quantum field theory. Its scope is illustrated by specific examples, including effective field theory, Stelle gravity, infinite derivative gravity, and Asymptotic Safety.

Analytic infinite derivative gravity, R2-like inflation, quantum gravity and CMB

Emergence of [Formula: see text] inflation, which is the best fit framework for CMB observations till date, comes from the attempts to attack the problem of quantization of gravity which in turn have resulted in the trace anomaly discovery. Further developments in trace anomaly and different frameworks aiming to construct quantum gravity indicate an inevitability of nonlocality in fundamental physics at small time and length scales. A natural question would be to employ the [Formula: see text] inflation as a probe for signatures of nonlocality in the early Universe physics. Recent advances of embedding [Formula: see text] inflation in a string theory inspired nonlocal gravity modification provide very promising theoretical predictions connecting the nonlocal physics in the early Universe and the forthcoming CMB observations.