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Galileons on Cosmological Backgrounds

Garrett Goon, Kurt Hinterbichler, Mark Trodden

Abstract

We construct four-dimensional effective field theories of a generalized DBI galileon field, the dynamics of which naturally take place on a Friedmann-Robertson-Walker spacetime. The theories are invariant under non-linear symmetry transformations, which can be thought of as being inherited from five-dimensional bulk Killing symmetries via the probe brane technique through which they are constructed. The resulting model provides a framework in which to explore the cosmological role that galileons may play as the universe evolves.

Galileons on Cosmological Backgrounds

Abstract

We construct four-dimensional effective field theories of a generalized DBI galileon field, the dynamics of which naturally take place on a Friedmann-Robertson-Walker spacetime. The theories are invariant under non-linear symmetry transformations, which can be thought of as being inherited from five-dimensional bulk Killing symmetries via the probe brane technique through which they are constructed. The resulting model provides a framework in which to explore the cosmological role that galileons may play as the universe evolves.

Paper Structure

This paper contains 17 sections, 63 equations, 1 figure, 1 table.

Table of Contents

  1. Introduction
  2. Review of the brane construction for DBI galileons
  3. DBI Galileons on a Gaussian normal foliation
  4. Induced quantities and other ingredients
  5. The Lagrangians
  6. Global symmetries
  7. DBI Galileons on cosmological spaces
  8. Embedding 4D FRW in 5D Minkowski
  9. Global symmetries for FRW
  10. Minisuperspace Lagrangians
  11. Solutions, fluctuations, and small field limits
  12. Simple solutions and stability
  13. Small $\pi$ symmetries
  14. Galileon-like limits
  15. Conclusion
  16. ...and 2 more sections

Figures (1)

  • Figure 1: The embedding of an FRW brane in 5D Minksowski space for the case $a(t)=t^{1/2}$.