Feynman rules for stochastic inflationary correlators
Abstract
We elaborate on the functional integral describing stochastic dynamics of a spectator field during inflation, comparing its diagrammatic expansion to that obtained directly from a perturbative solution of the corresponding Langevin equation. We state Feynman rules for computing arbitrary temporal n-point functions and perform some illustrative computations for a λphi4 interaction, paying attention to the role played by a functional Jacobian determinant in the path integral. We also briefly consider the case when the field contributes to the expansion rate, making the noise multiplicative, which introduces additional vertices.
- Publication:
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Journal of Cosmology and Astroparticle Physics
- Pub Date:
- May 2020
- DOI:
- 10.1088/1475-7516/2020/05/046
- arXiv:
- arXiv:2002.03402
- Bibcode:
- 2020JCAP...05..046B
- Keywords:
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- General Relativity and Quantum Cosmology;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- High Energy Physics - Theory
- E-Print:
- 30 pages