Asymptotically safe Starobinsky inflation

We revisit Starobinsky inflation in a quantum gravitational context, by means of the exact renormalization group (RG). We calculate the nonperturbative beta functions for Newton’s “constant” G and the dimensionless R^2 coupling, and show that there exists an attractive UV fixed point where the latte...

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Main Authors: Copeland, Edmund J., Rahmede, Christoph, Saltas, Ippocratis D.
Format: Article
Published: American Physical Society 2015
Online Access:https://eprints.nottingham.ac.uk/42225/
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author Copeland, Edmund J.
Rahmede, Christoph
Saltas, Ippocratis D.
author_facet Copeland, Edmund J.
Rahmede, Christoph
Saltas, Ippocratis D.
author_sort Copeland, Edmund J.
building Nottingham Research Data Repository
collection Online Access
description We revisit Starobinsky inflation in a quantum gravitational context, by means of the exact renormalization group (RG). We calculate the nonperturbative beta functions for Newton’s “constant” G and the dimensionless R^2 coupling, and show that there exists an attractive UV fixed point where the latter one vanishes but not the former one, and we provide the corresponding beta functions. The smallness of the R^2 coupling, required for agreement with inflationary observables, is naturally ensured by its vanishing at the UV fixed point, ensuring the smallness of the primordial fluctuations, as well as providing a theoretical motivation for the initial conditions needed for successful inflation in this context. We discuss the corresponding RG dynamics, showing both how inflationary and classical observations define the renormalization conditions for the couplings, and also how the UV regime is connected with lower energies along the RG flow. Finally, we discuss the consistency of our results when higher-order curvature corrections are included, and show that they are robust to the inclusion of R^3 corrections.
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spelling nottingham-422252020-05-04T17:08:11Z https://eprints.nottingham.ac.uk/42225/ Asymptotically safe Starobinsky inflation Copeland, Edmund J. Rahmede, Christoph Saltas, Ippocratis D. We revisit Starobinsky inflation in a quantum gravitational context, by means of the exact renormalization group (RG). We calculate the nonperturbative beta functions for Newton’s “constant” G and the dimensionless R^2 coupling, and show that there exists an attractive UV fixed point where the latter one vanishes but not the former one, and we provide the corresponding beta functions. The smallness of the R^2 coupling, required for agreement with inflationary observables, is naturally ensured by its vanishing at the UV fixed point, ensuring the smallness of the primordial fluctuations, as well as providing a theoretical motivation for the initial conditions needed for successful inflation in this context. We discuss the corresponding RG dynamics, showing both how inflationary and classical observations define the renormalization conditions for the couplings, and also how the UV regime is connected with lower energies along the RG flow. Finally, we discuss the consistency of our results when higher-order curvature corrections are included, and show that they are robust to the inclusion of R^3 corrections. American Physical Society 2015-05-22 Article PeerReviewed Copeland, Edmund J., Rahmede, Christoph and Saltas, Ippocratis D. (2015) Asymptotically safe Starobinsky inflation. Physical Review D, 91 (10). pp. 103530-1. ISSN 2470-0029 https://journals.aps.org/prd/abstract/10.1103/PhysRevD.91.103530 doi:10.1103/PhysRevD.91.103530 doi:10.1103/PhysRevD.91.103530
spellingShingle Copeland, Edmund J.
Rahmede, Christoph
Saltas, Ippocratis D.
Asymptotically safe Starobinsky inflation
title Asymptotically safe Starobinsky inflation
title_full Asymptotically safe Starobinsky inflation
title_fullStr Asymptotically safe Starobinsky inflation
title_full_unstemmed Asymptotically safe Starobinsky inflation
title_short Asymptotically safe Starobinsky inflation
title_sort asymptotically safe starobinsky inflation
url https://eprints.nottingham.ac.uk/42225/
https://eprints.nottingham.ac.uk/42225/
https://eprints.nottingham.ac.uk/42225/