3-point function of currents for holographic cosmology and monopole non-Gaussianities

TL;DR

This paper calculates the three-point function of currents in a holographic cosmology model, linking it to monopole non-Gaussianities, and shows the universality and finiteness of the results.

Contribution

It provides the first computation of the three-point current correlator in a holographic cosmology setting, demonstrating its independence from potential details.

Findings

The three-point function is UV and IR finite.

The three-point function satisfies Ward identities.

Non-Gaussianities are universal within the model.

Abstract

In this paper we present the calculation of the three-point function in momentum space of currents for a $SO(3)$ global symmetry, in a three-dimensional toy model within phenomenological holographic cosmology. Since the two-point function gives, via electric-magnetic duality, the resolution of the cosmological monopole problem, the three-point function is related to the monopole non-Gaussianities. We check that the final result is UV and IR finite and satisfies the transverse Ward identities and consider the $k_1\ll k_2,k_3$ case, relevant for cosmology. We also show that the two-loop result for the 3-point function is completely independent of the explicit form of the potential, meaning that, like the solution to the monopole problem, also the non-Gaussianities are universal within the phenomenological holographic cosmology.