Primordial features from linear to nonlinear scales

Abstract

Sharp features in the primordial power spectrum are a powerful window into the inflationary epoch. To date, the cosmic microwave background (CMB) has offered the most sensitive avenue to search for these signatures. In this paper, we demonstrate the power of large-scale structure observations to surpass the CMB as a probe of primordial features. We show that the signatures in galaxy surveys can be separated from the broadband power spectrum and are as robust to the nonlinear evolution of matter as the standard baryon acoustic oscillations. As a result, analyses can exploit a significant range of scales beyond the linear regime available in the datasets. We develop a feature search for large-scale structure, apply it to BOSS DR12 data and find new bounds on oscillatory features that exceed the sensitivity of Planck for a significant range of frequencies. Moreover, we forecast that the next generation of galaxy surveys, such as DESI and Euclid, will be able to improve current constraints by up to an order of magnitude over an expanded frequency range. References 517 This result has also been independently derived in [43] using ω log 1 as an expansion parameter. 8 These findings are also confirmed by analyses of N -body simulations performed in [44].

The Hunt for Primordial Interactions in the Large-Scale Structures of the Universe

“…Sharp features in the potential or in the internal field space can arise from a variety of models [63][64][65][66][67] and they can also be studied in the context of the effective field theory of inflation [68]. Such features typically show up primarily in the power spectrum and constrains can be put with observations both of the CMB [9] and LSS [14], so non-Gaussianities can be used as a cross-check.…”

“…The latest constraint was put by the eBOSS collaboration [15] and gives −51 < f loc NL < 21 at 95% confidence level and the full data analysis of the experiment including quasars might reach the CMB sensitivity. A strong effort in forecasting the possible imprint of primordial non-Gaussianity in LSS has been pushing the limits to order O(1) for local-type non-Gaussianities 14 and O(10) for equilateral and orthogonal ones [16,19,21,30,280,281,285,343,. Several future surveys such as SPHEREx [16], Euclid [408], MeerKAT+DES [411] and SKA [19] might achieve these limits.…”

“…Moreover, the inflationary environment most probably does not involve fields and interactions of our standard model of particle physics, the elementary particles we are made of being generated at a later stage of cosmic evolution. The bright side is that any new discovery is a clear window on new physics, being able to explore energies as high as 10 14 GeV, just a couple of orders of magnitude away from the Planck energy scale, thus providing us the best hope of experimentally probing quantum gravity.…”

“…However, recent developments in large-scale structure (LSS) theory and observations have demonstrated that LSS can provide better constraints than the CMB in the near future. A recent analysis showed the first such example: using Baryon Acoustic Oscillations data from the BOSS collaboration [13], the authors of [14] have put constraints on primordial features that are stronger than CMB ones [6]. For primordial non-Gaussianity, results from eBOSS collaboration have given the most recent constraints on local type primordial non-Gaussianity [15] and are expected to reach CMB sensitivity including the full set of data in the next few months.…”

Consistency of Planck Data With Power-Law Primordial Scalar Power Spectrum

“…For instance see Danielsson (2002); Martin & Brandenberger (2003); Bozza et al (2003); Chen (2011); Jackson & Shiu (2013); Flauger et al (2017) for models of global oscillation and Adams et al (2001); Chen et al (2007); Achúcarro et al (2011); Miranda et al (2012); Bartolo et al (2013) for localized oscillatory features. The parameters of the various models of early Universe have been constrained by different cosmological data (e.g., Meerburg et al 2014;Beutler et al 2019;Planck Collaboration et al 2020b). Forecasts have also been made on the detectability of their imprints with future surveys (e.g., Huang et al 2012;Chen et al 2016;Ballardini et al 2016;Xu et al 2016;Beutler et al 2019;Li et al 2021).…”