Spurious gauge-invariance of higher-order contributions to the spectral energy density of the relic gravitons. (arXiv:2005.04962v1 [hep-th])
Spurious gauge-invariance of higher-order contributions to the spectral energy density of the relic gravitons. (arXiv:2005.04962v1 [hep-th]) <a href="http://arxiv.org/find/hep-th/1/au:+Giovannini_M/0/1/0/all/0/1">Massimo Giovannini</a> In the same way as the energy density associated with the tensor modes of the geometry modifies the evolution of the curvature perturbations, the scalar modes may also indirectly affect the cosmic backgrounds of relic gravitons by inducing higher-order corrections that are only superficially gauge-invariant. This spurious gauge-invariance gets manifest when the effective anisotropic stresses, computed in different coordinate systems, are preliminarily expressed in a form that only depends on the curvature inhomogeneities defined on comoving orthogonal hypersurfaces and on their corresponding time derivatives. Using thisRead More →