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Universal attractor for inflation at strong coupling.

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We discovered a universal attractor in cosmological models with nonminimal coupling to gravity. This finding is independent of the scalar potential and aligns with Planck satellite data.

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Area of Science:

  • Cosmology
  • Theoretical Physics
  • Gravitational Physics

Background:

  • Nonminimal coupling theories explore modifications to Einstein's gravity.
  • The inflaton sector is crucial for understanding cosmic inflation.
  • Previous studies identified attractors in specific scalar field models.

Purpose of the Study:

  • To investigate the behavior of cosmological models with a novel nonminimal coupling between gravity and the inflaton sector.
  • To determine if a universal attractor exists for large coupling values.
  • To analyze the implications of this attractor for inflationary cosmology and observational data.

Main Methods:

  • Introducing a new nonminimal coupling term in the gravitational action.
  • Analyzing the dynamical system describing the evolution of the scalar field and gravitational variables.
  • Investigating the asymptotic behavior of the system for large coupling constants.

Main Results:

  • A universal attractor is found to exist for large values of the nonminimal coupling.
  • This attractor's behavior is independent of the specific form of the scalar potential.
  • The attractor's parameter values fall within the 'sweet spot' favored by Planck satellite observations.

Conclusions:

  • The novel nonminimal coupling leads to a robust universal attractor in inflationary cosmology.
  • This attractor provides a compelling framework for models of cosmic inflation.
  • The results offer new insights into the interplay between gravity, scalar fields, and early universe cosmology.