Oscillating Bispectra and Galaxy Clustering: A Novel Probe of Inflationary Physics with Large-Scale Structure

TL;DR

This paper explores how oscillations in the primordial bispectrum, caused by features in the inflaton potential, influence galaxy clustering and halo bias, offering new ways to probe inflationary physics through large-scale structure observations.

Contribution

It demonstrates that oscillatory features in the inflationary bispectrum imprint distinctive scale-dependent and mass-dependent signatures in halo bias, revealing new observational probes of inflation.

Findings

Non-Gaussian halo bias exhibits strong scale dependence similar to local models.

Resonant non-Gaussianity causes halo bias to oscillate with halo mass, a unique signature.

Clustering is enhanced at specific mass scales linked to potential features.

Abstract

Many models of inflation predict oscillatory features in the bispectrum of primordial fluctuations. Since it has been shown that primordial non-Gaussianity can lead to a scale-dependent halo bias, we investigate the effect of oscillations in the three-point function on the clustering of dark-matter halos. Interestingly, we find that features in the inflaton potential such as oscillations or sharp steps get imprinted in the mass dependence of the non-Gaussian halo bias. In this paper, we focus on models displaying a sharp feature in the inflaton potential as well as Resonant non-Gaussianity. In both cases, we find a strong scale dependence for the non-Gaussian halo bias with a slope similar to that of the local model. In the resonant case, we find that the non-Gaussian bias oscillates with halo mass, a novel feature that is unique to this type of models. In the case of a sharp feature in the inflaton potential, we find that the clustering of halos is enhanced at the mass scale corresponding to the Fourier mode that exited the horizon when the inflaton was crossing the feature in the potential. Both of these are new effects that open the possibility of characterizing the inflationary potential with large-scale-structure surveys. We briefly discuss the prospects for detecting these non-Gaussian effects.