n-DBI Gravity: A Short Overview

  • Flávio S. Coelho
  • Carlos Herdeiro
  • Shinji Hirano
  • Yuki Sato
Conference paper
Part of the Springer Proceedings in Mathematics & Statistics book series (PROMS, volume 60)


We present a model of gravity motivated by the Dirac–Born–Infeld type conformal scalar theory it yields when the Universe is conformally flat. We show that, if the Universe is permeated by a perfect fluid of radiation, the theory naturally predicts two eras of accelerated expansion mediated by a radiation dominated epoch, with a large hierarchy between the two effective cosmological constants, thus providing an alternative inflation scenario. This theory, dubbed n-DBI gravity, contains a preferred unit vector field, everywhere time-like, which breaks diffeomorphism invariance and gives rise to an extra scalar degree of freedom. We analyze the dynamics of this mode and conclude that it is free from some of the pathologies found in similar models, namely the issues of vanishing lapse short distance instability and strong coupling. We also show that the standard black holes of General Relativity are solutions of this theory.


Black Hole Black Hole Solution Perfect Fluid Accelerate Expansion Ricci Scalar 
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F.C. is funded by FCT through the grants SFRH/BD/60272/2009. This work was partially supported by the Grant-in-Aid for Nagoya University Global COE Program (G07), by FCT (Portugal) through the project PTDC/FIS/116625/2010 and by the Marie Curie Action NRHEP295189-FP7-PEOPLE-2011-IRSES.


  1. 1.
    D. Blas, O. Pujolas and S. Sibiryakov, “On the Extra Mode and Inconsistency of Hořava Gravity,” JHEP 0910, 029 (2009).MathSciNetCrossRefGoogle Scholar
  2. 2.
    D. Blas, O. Pujolas and S. Sibiryakov, “Consistent Extension of Horava Gravity,” Phys. Rev. Lett. 104 181302 (2010).MathSciNetCrossRefGoogle Scholar
  3. 3.
    F. S. Coelho, C. Herdeiro and M. Wang, “n-DBI gravity, maximal slicing and the Kerr geometry,” arXiv:1301.1070 (2012).Google Scholar
  4. 4.
    F. S. Coelho, C. Herdeiro, S. Hirano and Y. Sato, “Scalar graviton in n-DBI gravity,” Phys. Rev. D 86 064009 (2012).CrossRefGoogle Scholar
  5. 5.
    M. Henneaux, A. Kleinschmidt and G. Lucena Gomez, “A dynamical inconsistency of Hořava gravity,” Phys. Rev. D 81, 064002 (2010).MathSciNetCrossRefGoogle Scholar
  6. 6.
    C. Herdeiro and S. Hirano, “Scale invariance and a gravitational model with non-eternal inflation,” JCAP 1205 031 (2012).CrossRefGoogle Scholar
  7. 7.
    C. Herdeiro, S. Hirano and Y. Sato, “n-DBI gravity,” Phys. Rev. D 84 124048 (2011).CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Flávio S. Coelho
    • 1
  • Carlos Herdeiro
    • 1
  • Shinji Hirano
    • 2
  • Yuki Sato
    • 2
  1. 1.Departamento de Física da Universidade de Aveiro and I3NAveiroPortugal
  2. 2.Department of PhysicsNagoya UniversityNagoyaJapan

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