# Inflation with multiple sound speeds: A model of multiple DBI type actions and non-Gaussianities

@article{Cai2009InflationWM, title={Inflation with multiple sound speeds: A model of multiple DBI type actions and non-Gaussianities}, author={Yi Cai and Haijuan Xia}, journal={Physics Letters B}, year={2009}, volume={677}, pages={226-234} }

## 113 Citations

### Local non-Gaussianity from rapidly varying sound speeds

- Physics
- 2012

We study the effect of non-trivial sound speeds on local-type non-Gaussianity during multiple-field inflation. To this end, we consider a multiple-DBI model and use the δN formalism to track the…

### Local non-Gaussianity from rapidly varying sound speeds

- Physics
- 2012

We study the effect of non-trivial sound speeds on local-type non-Gaussianity during multiple-field inflation. To this end, we consider a multiple-DBI model and use the δN formalism to track the…

### Preheating in a DBI Inflation Model

- Physics
- 2013

We study the preheating process in a model of DBI inflation with a DBI-type inflaton coupling to a canonical entropy field. At the end of inflation, the inflaton field oscillates around its vacuum…

### Non-Gaussianity in multi-sound-speed disformally coupled inflation

- Physics
- 2016

Most, if not all, scalar-tensor theories are equivalent to General Relativity with a disformally coupled matter sector. In extra-dimensional theories such a coupling can be understood as a result of…

### Inhomogeneous reheating scenario with DBI fields

- Physics
- 2010

We discuss a new mechanism which can be responsible for the origin of the primordial perturbation in inflationary models, the inhomogeneous DBI reheating scenario. Light DBI fields fluctuate during…

### Covariant second-order perturbations in generalized two-field inflation

- Physics, Computer Science
- 2014

It is demonstrated that kinetic-term derivatives and covariant field derivatives do commute in a proper covariant framework, which was not realized before in the literature, and a set of generalized slow-roll parameters is defined, using a unified notation.

### Combined local and equilateral non-Gaussianities from multifield DBI inflation

- Physics
- 2009

We study multifield aspects of Dirac-Born-Infeld (DBI) inflation. More specifically, we consider an inflationary phase driven by the radial motion of a D-brane in a conical throat and determine how…

### Primordial fluctuations and non-Gaussianities from multifield DBI Galileon inflation

- Physics
- 2011

We study a cosmological scenario in which the DBI action governing the motion of a D3-brane in a higher-dimensional spacetime is supplemented with an induced gravity term. The latter reduces to the…

### Primordial perturbations from string inflation

- Physics
- 2014

In this work we explore the correspondence between the physical processes associated with inflationary models inspired by string theory and the subsequent non-Gaussian signatures imprinted in the…

## References

SHOWING 1-10 OF 91 REFERENCES

### Primordial perturbations and non-Gaussianities in DBI and general multifield inflation

- Physics
- 2008

We study cosmological perturbations in general inflation models with multiple scalar fields and arbitrary kinetic terms, with special emphasis on the multifield extension of Dirac-Born-Infeld (DBI)…

### Perturbations in generalized multi-field inflation

- Physics
- 2008

We study the linear perturbations of multi-field inflationary models governed by a Lagrangian which is a general function of the scalar fields and of a global kinetic term combining their spacetime…

### Large non-Gaussianities in single-field inflation

- Computer Science
- 2007

While adding features to a potential can improve the fit to the two-point function, these are generically associated with a greatly enhanced signal at the three-point level, which may lead to a consistency check on models of inflation with non-smooth potentials.

### Primordial fluctuations and non-Gaussianities in multifield Dirac-Born-Infeld inflation.

- PhysicsPhysical review letters
- 2008

It is shown that the adiabatic and entropy modes propagate with a common effective sound speed and are thus amplified at the sound horizon crossing and this could strongly affect the observable curvature power spectrum as well as the amplitude of non-Gaussianities, although their shape remains as in the single-field Dirac-Born-Infeld case.

### Generation and characterization of large non-Gaussianities in single field inflation

- Computer Science
- 2008

Two distinct mechanisms by which a non-trivial potential can generate large non-Gaussianities are discussed, and a significantly improved approach to regularizing and numerically evaluating the integrals that contribute to the three-point function is presented.

### Near scale invariance with modified dispersion relations

- Physics
- 2006

We describe a novel mechanism for generating a nearly scale invariant spectrum of adiabatic perturbations during a non-inflationary stage. It relies on a modified dispersion relation that contains…

### The shape of non-Gaussianities

- Economics
- 2004

We study the dependence on the configuration in momentum space of the primordial three-point function of density perturbations in several different scenarios: standard slow-roll inflation, curvaton…

### Dynamics of Assisted Inflation

- Mathematics, Physics
- 1999

We investigate the dynamics of the recently proposed model of assisted inflation. In this model an arbitrary number of scalar fields with exponential potentials evolve towards an inflationary scaling…

### Non-Gaussianities from ekpyrotic collapse with multiple fields

- Physics
- 2007

We compute the non-Gaussianity of the curvature perturbation generated by ekpyrotic collapse with multiple fields. The transition from the multi-field scaling solution to a single-field dominated…

### Adiabatic and entropy perturbations from inflation

- Physics, Environmental Science
- 2000

We study adiabatic ~curvature! and entropy ~isocurvature! perturbations produced during a period of cosmological inflation that is driven by multiple scalar fields with an arbitrary interaction…