# Schwinger-Keldysh mechanism in extended quasi single field inflation

## TL;DR

This paper extends the quasi-single field inflation model by incorporating multiple semi-heavy isocurvaton fields and employs the Schwinger-Keldysh mechanism to efficiently analyze the bispectrum and trispectrum shapes.

## Contribution

It introduces a diagrammatic approach using the Schwinger-Keldysh mechanism for analyzing complex inflation models with multiple fields, simplifying calculations.

## Key findings

- Calculated amplitudes and shapes of bispectrum and trispectrum.
- Demonstrated the efficiency of the Schwinger-Keldysh diagrammatic method.
- Provided insights into the mass and coupling spectroscopy of fields during inflation.

## Abstract

We study an extension of quasi-single field model of inflation containing multiple semi-heavy isocurvaton fields using the Schwinger-Keldysh mechanism. We calculate the amplitudes and the shapes of the bispectrum and the trispectrum. We show that the diagrammatic approach associated with the Schwinger-Keldysh mechanism simplifies the analysis considerably compared to standard in-in formalism. This method is helpful to study the spectroscopy of masses and couplings of light and semi-heavy fields during inflation.