# Unique contributions to the scalar bispectrum in `just enough inflation'

## TL;DR

This paper investigates how a finite-duration inflation driven by a scalar field with high initial velocity affects the scalar bispectrum, revealing boundary term dominance and violations of the consistency relation on large scales.

## Contribution

It uncovers the dominance of boundary terms in the scalar bispectrum and demonstrates the violation of the consistency relation in a specific inflation scenario.

## Key findings

- Boundary terms dominate the scalar bispectrum over bulk terms.
- The consistency relation for $f_{NL}$ is violated on large scales.
- Initial contributions can significantly increase $f_{NL}$.

## Abstract

A scalar field rolling down a potential with a large initial velocity results in inflation of a finite duration. Such a scenario suppresses the scalar power on large scales improving the fit to the cosmological data. We find that the scenario leads to a hitherto unexplored situation wherein the boundary terms dominate the contributions to the scalar bispectrum over the bulk terms. We show that the consistency relation governing the non-Gaussianity parameter $f_{_{\rm NL}}$ is violated on large scales and that the contributions at the initial time can substantially enhance the value of $f_{_{\rm NL}}$.