Do We Have Evidence for New Physics in the Sky?

TL;DR

This paper discusses how to identify unique observable signatures of new physics, like string theory, in cosmological data by analyzing discrepancies between large scale structure and CMB observations.

Contribution

It reviews recent progress in distinguishing genuine new physics signals from inflationary physics effects through cross-correlation techniques.

Findings

Discrepancies in source terms can indicate new physics signatures.

Cross-correlation of weak lensing and CMB spectra is a promising method.

Identifying unique signatures remains a key challenge in cosmology.

Abstract

Predicting signatures of string theory on cosmological observables is not sufficient. Often the observable effects string theory may impact upon the cosmological arena may equally be predicted by features of inflationary physics. The question: what observable signatures are unique to new physics, is thus of crucial importance for claiming evidence for the theory. Here we discuss recent progress in addressing the above question. The evidence relies on identifying discrepancies between the source terms that give rise to large scale structure (LSS) and CMB, by cross-correlating the weak lensing potential maps LSS with the CMB spectra.