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Adiabatic regularization of the graviton stress-energy tensor in de Sitter space-time

F. Finelli·G. Marozzi·G. P. Vacca·G. Venturi
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Abstract

We study the renormalized energy-momentum tensor of gravitons in a de Sitter space-time. After canonically quantizing only the physical degrees of freedom, we adopt the standard adiabatic subtraction used for massless minimally coupled scalar fields as a regularization procedure and find that the energy density of gravitons in the E(3) invariant vacuum is proportional to H^4, where H is the Hubble parameter, but with a positive sign. According to this result the scalar expansion rate, which is gauge invariant in de Sitter space-time, is increased by the fluctuations. This implies that gravitons may then add to conformally coupled matter in driving the Starobinsky model of inflation.

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F. Finelli, G. Marozzi, G. P. Vacca, G. Venturi. 2005-01-14. Adiabatic regularization of the graviton stress-energy tensor in de Sitter space-time. https://doi.org/10.1103/physrevd.71.023522

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