Low-energy effects in a higher-derivative gravity model with real and complex massive poles

TL;DR

This paper investigates the low-energy gravitational effects in a six-derivative quantum gravity model with complex and real massive poles, analyzing modifications to Newtonian potential and light bending.

Contribution

It constructs the modified Newton potential and studies gravitational light bending within a six-derivative gravity model, including cases with complex massive poles.

Findings

Modified Newton potential derived for the model

Light bending analyzed in classical and semiclassical frameworks

Complex poles do not violate unitarity in the theory

Abstract

The most simple superrenormalizable model of quantum gravity is based on the general local covariant six-derivative action. In addition to graviton such a theory has massive scalar and tensor modes. It was shown recently that in the case when the massive poles emerge in complex conjugate pairs, the theory has also unitary $S$-matrix and hence can be seen as a candidate to be a consistent quantum gravity theory. In the present work we construct the modified Newton potential and explore the gravitational light bending in a general six-derivative theory, including the most interesting case of complex massive poles. In the case of the light deflection the results are obtained within classical and semiclassical approaches.