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Singularities in loop quantum cosmology.

Thomas Cailleteau1, Antonio Cardoso, Kevin Vandersloot

  • 1Physique Fondamentale et appliquée, Universite Paris-Sud 11, 91405 Orsay Cedex, France. thomas.cailleteau@gmail.com

Physical Review Letters
|December 31, 2008
PubMed
Summary
This summary is machine-generated.

Loop quantum cosmology (LQC) effective equations can still produce curvature singularities, even when avoiding big bang singularities. Simple scalar field models lead to sudden singularities with diverging Ricci curvature.

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Area of Science:

  • Cosmology
  • Theoretical Physics
  • Quantum Gravity

Background:

  • Loop quantum cosmology (LQC) offers a framework to resolve the big bang singularity.
  • Effective Friedmann dynamics in LQC are studied to understand early universe behavior.

Purpose of the Study:

  • To investigate whether simple scalar field models in LQC can avoid curvature singularities.
  • To analyze the nature of singularities that may arise in effective LQC.

Main Methods:

  • Analysis of singular solutions in spatially flat Friedmann-Robertson-Walker cosmologies.
  • Inclusion of canonical scalar fields with negative exponential potentials.
  • Inclusion of phantom scalar fields with positive potentials.

Main Results:

  • Simple scalar field models can lead to curvature singularities in effective LQC.
  • Sudden singularities are found where Hubble rate is bounded but Ricci curvature scalar diverges.
  • Big bang and big rip singularities are avoided, but not all curvature singularities.

Conclusions:

  • The effective equations of LQC alone are insufficient to prevent all curvature singularities.
  • Scalar field models play a crucial role in the occurrence of singularities.
  • Further theoretical developments may be needed to fully resolve singularities in LQC.