Inflation

• DOI: 10.48550/arxiv.2203.08128
• Publication Date: 2022-01-01
• Authors: Achúcarro, Ana; Biagetti, Matteo; Braglia, Matteo; Cabass, Giovanni; Castorina, Emanuele; Caldwell, Robert; Chen, Xingang; Coulton, William; Flauger, Raphael; Fumagalli, Jacopo; Ivanov, Mikhail M.; Lee, Hayden; Maleknejad, Azadeh; Meerburg, P. Daniel; Dizgah, Azadeh Mo...; Palma, Gonzalo A.; Renaux-Petel, Séb...; Pimentel, Guilher...; Wallisch, Benjamin; Wandelt, Benjamin D.; Witkowski, Lukas T.; Wu, W.L. Kimmy
• Keywords: High Energy Physics - Theory; cosmological model; Cosmology and Nongalactic Astrophysics (astro-ph.CO); FOS: Physical sciences; 01 natural sciences; 7. Clean energy; High Energy Physics - Phenomenology (hep-ph); 0103 physical sciences; energy: density; non-Gaussianity: primordial; space-time: expansion; hep-th; fluctuation: primordial; gravitational radiation: primordial; hep-ph; sensitivity; [PHYS.HPHE] Physics [physics]/High Energy Physics - Phenomenology [hep-ph]; High Energy Physics - Phenomenology; High Energy Physics - Theory (hep-th); 13. Climate action; inflation: signature; astro-ph.CO; [PHYS.HTHE] Physics [physics]/High Energy Physics - Theory [hep-th]; expansion: acceleration; [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph]; statistical; Astrophysics - Cosmology and Nongalactic Astrophysics

Cosmic inflation provides a window to the highest energy densities accessible in nature, far beyond those achievable in any realistic terrestrial experiment. Theoretical insights into the inflationary era and its observational probes may therefore shed unique light on the physical laws underlying our universe. This white paper describes our current theoretical understanding of the inflationary era, with a focus on the statistical properties of primordial fluctuations. In particular, we survey observational targets for three important signatures of inflation: primordial gravitational waves, primordial non-Gaussianity and primordial features. With the requisite advancements in analysis techniques, the tremendous increase in the raw sensitivities of upcoming and planned surveys will translate to leaps in our understanding of the inflationary paradigm and could open new frontiers for cosmology and particle physics. The combination of future theoretical and observational developments therefore offer the potential for a dramatic discovery about the nature of cosmic acceleration in the very early universe and physics on the smallest scales.<br/>Contribution to Snowmass 2021; 103 pages, 8 figures, 378 endorsers; v2: minor changes<br/>