An Analytical Model of Inflation with Graceful Exit and Constraining it from Observations

An Analytical Model of Inflation with Graceful Exit and Constraining it from Observations | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article An Analytical Model of Inflation with Graceful Exit and Constraining it from Observations Subhankar Saha, Rajib Saha This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9614593/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract A rapidly inflating space driven by a simultaneously evolving scalar field influenced by a poten tial energy density (V (ϕ)) in very early universe is a fundamental mechanism that generated the tiny quantum perturbations that eventually form large scale gravitationally bound systems in our universe. In a traditional approach one starts with a suitable V (ϕ) for the field to describe this dynamics and predict observable quantities like scalar spectral index (ns) and tensor to scalar ratio (r). In this work, we take an alternative path by first specifying a scale factor a(t) that encapsulates some of the basic physically motivated characteristics. We derive the potential energy density and using it provide expressions of all necessary inflation parameters that are needed to connect to the two common inflationary observables, ns and r. Our results are fully analytic and exact and are expressed in terms of dynamical variables of time and scalar field itself, without assuming any slow roll conditions. However, slow roll conditions can easily be imposed on these complete analytical results to uncover the physics in the desired limit. The analysis can identify a time interval during which slow roll assumption can be assumed to be valid. Our inflationary dynamics does not suffer from the so-called ungraceful exit problem from the inflation. We show that our scale factor model predicts ns and r values consistent with the Planck, BICEP/Keck-18, and ACT observations in the context of minimally coupled scalar field with the gravity. Astrophysics and Cosmology Cosmology Inflation CMB Observations Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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In a traditional approach one starts with a suitable V (ϕ) for the field to describe this dynamics and predict observable quantities like scalar spectral index (ns) and tensor to scalar ratio (r). In this work, we take an alternative path by first specifying a scale factor a(t) that encapsulates some of the basic physically motivated characteristics. We derive the potential energy density and using it provide expressions of all necessary inflation parameters that are needed to connect to the two common inflationary observables, ns and r. Our results are fully analytic and exact and are expressed in terms of dynamical variables of time and scalar field itself, without assuming any slow roll conditions. However, slow roll conditions can easily be imposed on these complete analytical results to uncover the physics in the desired limit. The analysis can identify a time interval during which slow roll assumption can be assumed to be valid. 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