Galileon Cosmology

@inproceedings{Chow2009GalileonC,
  title={Galileon Cosmology},
  author={Nathan Chow and Justin Khoury},
  year={2009}
}
We study the cosmology of a galileon scalar-tensor theory, obtained by covariantizing the decoupling lagrangian of the Dvali-Gabadadze-Poratti (DGP) model. Despite being local in 3+1 dimensions, the resulting cosmological evolution is remarkably similar to that of the full 4+1-dimensional DGP framework, both for the expansion history and the evolution of density perturbations. As in the DGP model, the covariant galileon theory yields two branches of solutions, depending on the sign of the… 

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References

SHOWING 1-10 OF 149 REFERENCES

Galileon as a local modification of gravity

In the Dvali-Gabadadze-Porrati (DGP) model, the "self-accelerating" solution is plagued by a ghost instability, which makes the solution untenable. This fact, as well as all interesting departures

Classical and Quantum Consistency of the DGP Model

We study the Dvali-Gabadadze-Porrati model by the method of the boundary effective action. The truncation of this action to the bending mode π consistently describes physics in a wide range of

Self-Consistent Cosmological Simulations of DGP Braneworld Gravity

We perform cosmological N-body simulations of the Dvali-Gabadadze-Porrati (DGP) braneworld model, by solving the full nonlinear equations of motion for the scalar degree of freedom in this model, the

On the Initial Conditions in New Ekpyrotic Cosmology

New Ekpyrotic Cosmology is an alternative scenario of early universe cosmology in which the universe existed before the big bang. The simplest model relies on two scalar fields, whose entropy

New Ekpyrotic Cosmology

In this paper, we present a new scenario of the early universe that contains a pre-big bang ekpyrotic phase. By combining this with a ghost condensate, the theory explicitly violates the null energy

Strong Interactions and Stability in the DGP Model

The model of Dvali, Gabadadze, and Porrati (DGP) gives a simple geometrical setup in which gravity becomes 5-dimensional at distances larger than a length scale lambda(DGP). We show that this theory

Cascading gravity and degravitation

We construct a cascading brane model of gravity in which the behavior of the gravitational force law interpolates from (n+4)-dimensional to (n+3)-dimensional all the way down to 4-dimensional from

Nonperturbative Continuity in Graviton Mass versus Perturbative Discontinuity

We address the question whether a graviton could have a small nonzero mass. The issue is subtle for two reasons: there is a discontinuity in the mass in the lowest tree-level approximation, and,

Cascading gravity: extending the Dvali-Gabadadze-Porrati model to higher dimension.

We present a generalization of the Dvali-Gabadadze-Porrati scenario to higher codimensions which, unlike previous attempts, is free of ghost instabilities. The 4D propagator is made regular by
...