Effects of Finite-time Singularities on Gravitational Waves

Abstract

We analyze the impact of finite-time singularities on gravitational waves, in the context of $F(R)$ gravity. We investigate which singularities are allowed to occur during the inflationary era, when gravitational waves are considered, and we discuss the quantitative implications of each allowed singularity. As we show, only a pressure singularity, the so-called Type II and also a Type IV singularity are allowed to occur during the inflationary era. In the case of a Type II, the resulting amplitude of the gravitational wave is zero or almost zero, hence this pressure singularity has a significant impact on the primordial gravitational waves. The case of a Type IV singularity is more interesting since as we show, the singularity has no effect on the amplitude of the gravitational waves. Therefore, this result combined with the fact that the Type IV singularity affects only the dynamics of inflation, leads to the conclusion that the Universe passes smoothly through a Type IV singularity.

To appear in Astrophysics and Space Science

References in corpus (4)

• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• Inflationary cosmology in modified gravity theories
• The Matter Bounce Alternative to Inflationary Cosmology
• A quantitative analysis of singular inflation with scalar-tensor and modified gravity

Cited by in corpus (4)

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• Lorenz Gauge Fixing of $f(T)$ Teleparallel Cosmology
• Existence of Static Wormholes in $f(\mathcal{G},T)$ Gravity
• On the Expanding Phase of a Singular Bounce and Intermediate Inflation: The Modified Gravity Description