Model-Independent Signatures of New Physics in non-Gaussianity

Understand

We compute the model-independent contributions to the primordial bispectrum and trispectrum in de Sitter space due to high-energy physics.

• We do this by coupling a light inflaton to an auxiliary heavy field, and then evaluating correlation functions in the Schwinger-Keldysh "in-in" formalism.
• The high-energy physics produces corrections parametrized by $H/M$ where $H$ is the scale of inflation and $M$ is the mass of the heavy field.
• The bispectrum peaks near the elongated shape, but otherwise contains no features.