On the Gravitational Wave in de Sitter Spacetime

TL;DR

This paper proposes a new approach to gravitational waves in de Sitter spacetime, showing that gravitons have an effective mass consistent with spacetime curvature, challenging previous assumptions about their mass and existence.

Contribution

It introduces a covariant and conformally invariant gravitational wave equation, revealing that gravitons acquire an effective mass in de Sitter spacetime, distinct from prior perturbation methods.

Findings

Gravitons have an effective mass proportional to the square root of spacetime curvature.

The new approach resolves the sign issue in graviton mass in de Sitter spacetime.

Gravitons are not part of the metric field but have an effective mass in this framework.

Abstract

For there is always a wrong sign in the mass of graviton in the so-called perturbation expansion approximation of both Minkowski and de Sitter spacetimes, the existence of gravitational wave from the metric perturbation of de Sitter spacetime is doubtful. We try another way to start from the assumption that the gravitational wave equation should be both general covariant and conformal invariant and find that graviton is no longer a part of metric field, it has an effective mass of $m_g=\sqrt{R/6}=% \sqrt{2\Lambda/3}$ with correct sign in de Sitter spacetime, though it's intrinsic mass remains zero.