A smooth bouncing cosmology with scale invariant spectrum

By P. Creminelli, L. Senatore. 2007

266 citations recorded by the source corpus.

We present a bouncing cosmology which evolves from the contracting to the expanding phase in a smooth way, without developing instabilities or pathologies and remaining in the regime of validity of 4D effective field theory. A nearly scale invariant spectrum of perturbations is generated during the contracting phase by an isocurvature scalar with a negative exponential potential and then converted to adiabatic. The model predicts a slightly blue spectrum, , no observable gravitational waves and a high (but model dependent) level of non-Gaussianities with local shape. The model represents an explicit and predictive alternative to inflation, although, at present, it is clearly less compelling.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/6992c40b0d38876140254a061dd0dc3c8d173bfb

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Citations in the corpus

NINE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP) OBSERVATIONS: FINAL MAPS AND RESULTS (2012, background): “…curvaton models (Linde & Mukhanov 1997; Lyth et al. 2003) and variable reheating models (Dvali et al. 2004; Zaldarriaga 2004), and also to some alternatives to inflation, such as “new” ekpyrosis (Creminelli & Senatore 2007; Buchbinder et al. 2007) and cyclic (Lehners & Steinhardt 2008a,b) models.”
Primordial Non-Gaussianity and Bispectrum Measurements in the Cosmic Microwave Background and Large-Scale Structure (2010, unknown): “NL (Buchbinder et al., 2008; Creminelli & Senatore, 2007; Koyama et al., 2007; Lehners & Steinhardt, 2008a,b).”
An infinite set of Ward identities for adiabatic modes in cosmology (2013, background): “Conversely, to observe a significant 3-point function in this limit requires violating one of the assumptions above, for instance through additional scalar fields [23–28] or an unstable background [29, 30, 33, 34].”
The Effective Field Theory of Inflation (2007, background): “From this point of view, our approach makes clearer the relationship among inflation, theories of modification of gravity and theories which violate the Null Energy Condition (equivalent to Ḣ > 0 in the cosmological context) like the bouncing models [1, 29, 30].”
On the consistency relation of the three-point function in single-field inflation (2007, background): “Outside of the inflationary paradigm, the recently proposed new bouncing cosmology [7]–[9], though less compelling than inflation, predicts a potentially detectable non-Gaussian signal that violates the consistency relation [9].”
Beyond the Cosmological Standard Model (2014, unknown): “Another model which has attracted considerable attention is the ghost condensate [445], which can be used to violate the null energy condition and constuction bouncing cosmologies [239, 446, 447].”
Galaxy Bias and non-Linear Structure Formation in General Relativity (2011, background): “The so-called local kind of non-Gaussianities [25] that can be produced in multifield inflationary models [26, 27] or in the new bouncing cosmology [28] provides an example where σM depends explicitly on the long wavelength amplitude ζ (7).”
Shape of primordial non-Gaussianity and the CMB bispectrum (2008, unknown): “[48] Paolo Creminelli and Leonardo Senatore.”
Towards a nonsingular bouncing cosmology (2012, background): “One way to achieving such a scenario is via a ghost condensate field φ [8, 42, 44] in which the Lorentz symmetry is broken spontaneously in the infrared, with the kinetic term for φ taking on a nonvanishing expectation value.”
Exploring bouncing cosmologies with cosmological surveys (2014, background): “They appear in many theoretical settings where either the gravitational sector is modified as in Hor̆ava gravity [56–58], non-relativistic gravitational action[59], torsion gravity [60, 61], Lagrange-multiplier gravity [62, 63], nonlinear massive gravity [64] and non-local gravity [65], or by making”
Inflationary Cosmology after Planck 2013 (2014, background): “One may hope to avoid these problems in the ghost condensate theory; see a series of papers on this subject [187, 188, 189].”
Rapidly-Varying Speed of Sound, Scale Invariance and Non-Gaussian Signatures (2008, methodology): “This may come as a surprise since local non-Gaussianities usually require two scalar fields, as in the curvaton [14], modulated reheating [28], pre-big bang pump field [10] and New Ekpyrotic mechanisms [6, 29, 30, 31].”
Cosmology and Fundamental Physics with the Euclid Satellite (2012, background): “Thus, at least a second field is required to generate an almost scale-invariant spectrum of perturbations [485, 353, 246, 708, 484].”