Enhanced Inflation in the Dirac-Born-Infeld framework

Abstract

We consider the Einstein equations within the DBI scenario for a spatially flat Friedmann-Robertson-Walker (FRW) spacetime without a cosmological constant. We derive the inflationary scenario by applying the symmetry transformations which preserve the form of the Friedmann and conservation equations. These form invariance transformations generate a symmetry group parametrized by the Lorentz factor $\ga$. We explicitly obtain an inflationary scenario by the cooperative effect of adding energy density into the Friedmann equation. For the case of a constant Lorentz factor, and under the slow roll assumption, we find the transformation rules for the scalar and tensor power spectra of perturbations as well as their ratio under the action of the form invariance symmetry group. Within this case and due to its relevance for the inflationary paradigm, we find the general solution of the dynamical equations for a DBI field driven by an exponential potential and show a broad set of inflationary solutions. The general solution can be split into three subsets and all these behave asymptotically as a power law solution at early and at late times.

9 pages, revtex 4.1

References in corpus (33)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Cosmological Constraints from the SDSS Luminous Red Galaxies
• Observational Signatures and Non-Gaussianities of General Single Field Inflation
• Primordial perturbations and non-Gaussianities in DBI and general multi-field inflation
• A Microscopic Limit on Gravitational Waves from D-brane Inflation
• The Inflationary Trispectrum for Models with Large Non-Gaussianities
• Primordial fluctuations and non-Gaussianities in multi-field DBI inflation
• Primordial non-Gaussianity from the DBI Galileons
• Dynamics of Logamediate Inflation
• DBI-essence
• Phenomenology of D-Brane Inflation with General Speed of Sound
• Spinflation
• Internal space structure generalization of the quintom cosmological scenario
• Gravitational Wave Constraints on DBI Inflation
• On the full quantum trispectrum in multi-field DBI inflation
• Quantum modes in DBI inflation: exact solutions and constraints from vacuum selection
• Lorentz boost and non-Gaussianity in multi-field DBI-inflation
• Primordial Non-Gaussianity and Gravitational Waves: Observational Tests of Brane Inflation in String Theory
• Primordial Trispectrum from Entropy Perturbations in Multifield DBI Model
• N-flation from multiple DBI type actions
• Stochastic Inflation Revisited: Non-Slow Roll Statistics and DBI Inflation
• Latest inflation model constraints from cosmic microwave background measurements
• On Power Law Inflation in DBI Models
• A Consistency Relation for Power Law Inflation in DBI models
• Phantom cosmologies and fermions
• Inflationary potentials in DBI models
• Gravitational Wave Constraints on Multi-Brane Inflation
• k-essence in the DGP brane-world cosmology
• Bridging geometries and potentials in DBI cosmologies
• Inflation in DBI models with constant gamma
• Non-commutative Geometry Modified Non-Gaussianities of Cosmological Perturbation
• Duality invariance and cosmological dynamics
• Assisted Inflation from Geometric Tachyon