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  • Letter
  • Open Access

Minimal k-inflation in light of the conformal metric-affine geometry

Yusuke Mikura1,*, Yuichiro Tada1,†, and Shuichiro Yokoyama2,3,‡

  • 1Department of Physics, Nagoya University, Nagoya 464-8602, Japan
  • 2Kobayashi Maskawa Institute, Nagoya University, Chikusa, Aichi 464-8602, Japan
  • 3Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583, Japan

  • *mikura.yusuke@e.mbox.nagoya-u.ac.jp
  • †tada.yuichiro@e.mbox.nagoya-u.ac.jp
  • ‡shu@kmi.nagoya-u.ac.jp
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Phys. Rev. D 103, L101303 – Published 28 May, 2021

DOI: https://doi.org/10.1103/PhysRevD.103.L101303

Abstract

We motivate a minimal realization of slow-roll k-inflation by incorporating the local conformal symmetry and the broken global SO(1,1) symmetry in the metric-affine geometry. With use of the metric-affine geometry where both the metric and the affine connection are treated as independent variables, the local conformal symmetry can be preserved in each term of the Lagrangian and thus higher derivatives of scalar fields can be easily added in a conformally invariant way. Predictions of this minimal slow-roll k-inflation, ns∼0.96, r∼0.005, and cs∼0.03, are not only consistent with current observational data but also have a prospect to be tested by forthcoming observations.

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Phys. Rev. D 103, L101303– Published 28 May, 2021
  • Received 31 March 2021
  • Accepted 30 April 2021
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