Bimetric structure formation: non-Gaussian predictions

Abstract

The minimal bimetric theory employing a disformal transformation between matter and gravity metrics is known to produce exactly scale-invariant fluctuations. It has a purely equilateral non-Gaussian signal, with an amplitude smaller than that of DBI inflation (with opposite sign) but larger than standard inflation. We consider non-minimal bimetric models, where the coupling $B$ appearing in the disformal transformation ${\hat g}_{\mn}= g_{\mn} -B\partial_μϕ\partial_νϕ$ can run with $\varphi$. For power-law $B(\varphi )$ these models predict tilted spectra. For each value of the spectral index, a distinctive distortion to the equilateral property can be found. The constraint between this distortion and the spectral index can be seen as a "consistency relation" for non-minimal bimetric models.

17 pages, 2 figures. References and minor comments added in revised version

References in corpus (47)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Non-Gaussian features of primordial fluctuations in single field inflationary models
• Quantum Gravity at a Lifshitz Point
• k-Inflation
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Likelihoods and Parameters from the WMAP data
• The Ekpyrotic Universe: Colliding Branes and the Origin of the Hot Big Bang
• Lorentz invariance with an invariant energy scale
• Perturbations in k-inflation
• DBI in the Sky
• Pre-Big-Bang in String Cosmology
• Observational Signatures and Non-Gaussianities of General Single Field Inflation
• The Pre-Big Bang Scenario in String Cosmology
• Scalar Speed Limits and Cosmology: Acceleration from D-cceleration
• Generalized Lorentz invariance with an invariant energy scale
• Single field consistency relation for the 3-point function
• A Cyclic Model of the Universe
• A time varying speed of light as a solution to cosmological puzzles
• k-Essence, superluminal propagation, causality and emergent geometry
• Doubly Special Relativity
• Primordial non-gaussianities in single field inflation
• Superluminary Universe: A Possible Solution to the Initial Value Problem in Cosmology
• New Ekpyrotic Cosmology
• Effects of Scale-Dependent Non-Gaussianity on Cosmological Structures
• New varying speed of light theories
• Cuscuton: A Causal Field Theory with an Infinite Speed of Sound
• Generating Ekpyrotic Curvature Perturbations Before the Big Bang
• A smooth bouncing cosmology with scale invariant spectrum
• Enhancing the tensor-to-scalar ratio in simple inflation
• Constraining Running Non-Gaussianity
• Rapidly-Varying Speed of Sound, Scale Invariance and Non-Gaussian Signatures
• Cuscuton Cosmology: Dark Energy meets Modified Gravity
• Bi-metric Gravity and "Dark Matter"
• Ekpyrotic collapse with multiple fields
• Non-Gaussianity of quantum fields during inflation
• Bimetric varying speed of light theories and primordial fluctuations
• Speedy sound and cosmic structure
• Curvature perturbations from ekpyrotic collapse with multiple fields
• Quantum modes in DBI inflation: exact solutions and constraints from vacuum selection
• Assisting pre-big bang phenomenology through short-lived axions
• Tachyacoustic Cosmology: An Alternative to Inflation
• Scale Invariance without Inflation?
• Lieb-Robinson bounds and the speed of light from topological order
• Near Scale Invariance with Modified Dispersion Relations
• A scalar-tensor cosmological model with dynamical light velocity
• Regular two-component bouncing cosmologies and perturbations therein
• Seeding of Primordial Perturbations During a Decelerated Expansion
• DSR as an explanation of cosmological structure

Cited by in corpus (27)

• Imperfect Dark Energy from Kinetic Gravity Braiding
• Beyond $\Lambda$CDM: Problems, solutions, and the road ahead
• The Pseudo-Conformal Universe: Scale Invariance from Spontaneous Breaking of Conformal Symmetry
• Multi-scale gravity and cosmology
• Rainbow gravity and scale-invariant fluctuations
• Disformal transformation of cosmological perturbations
• Dimensional reduction in the sky
• Quantum gravity and gravitational-wave astronomy
• Generating Scale-Invariant Perturbations from Rapidly-Evolving Equation of State
• Non-Gaussianity in single field models without slow-roll
• Towards a Cosmological Dual to Inflation
• The critical geometry of a thermal big bang
• Scale Invariance via a Phase of Slow Expansion
• Varying electric charge in multiscale spacetimes
• Braneworld solutions from scalar field in bimetric theory
• Vacuum Cherenkov radiation and bremsstrahlung from disformal couplings
• Strong Coupling Problem with Time-Varying Sound Speed
• Bayesian evidence and predictivity of the inflationary paradigm
• Thermodynamics of $f(R)$ Gravity with Disformal Transformation
• Non-Gaussian Shape Recognition
• The phenomenology of squeezing and its status in non-inflationary theories
• Gravity, Cartan geometry, and idealized waywisers
• Attractor Solutions in Tachyacoustic Cosmology
• Non-Gaussian signatures of Tachyacoustic Cosmology
• An introduction to the physics of Cartan gravity
• Bimetric Gravity, Variable Speed of Light Cosmology and Planck2013
• Non-Gaussian Signatures of a Thermal Big Bang