General analytic predictions of two-field inflation and perturbative reheating

Elliston, Joseph; Orani, Stefano; Mulryne, David J.

doi:10.1103/physrevd.89.103532

Cited by 25 publications

(31 citation statements)

References 63 publications

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“…This is in agreement with the predictions of Nflation [35][36][37], and hence may be considered as a special, twofield case of that scenario. It is also the same as the predictions of inflation driven by two quadratic fields which decay at the same time [9,33,38]. Finally, note that if one took an equal prior range for ϕ Ã and σ Ã then the inflating curvaton would be much more common than the standard curvaton scenario, since it can occur for a much larger range of initial σ Ã values.…”

Section: The Inflating Curvatonsupporting

confidence: 69%

Comprehensive analysis of the simplest curvaton model

2014

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We carry out a comprehensive analysis of the simplest curvaton model, which is based on two non-interacting massive fields. Our analysis encompasses cases where the inflaton and curvaton both contribute to observable perturbations, and where the curvaton itself drives a second period of inflation. We consider both power spectrum and non-Gaussianity observables, and focus on presenting constraints in model parameter space. The fully curvaton-dominated regime is in some tension with observational data, while an admixture of inflaton-generated perturbations improves the fit. The inflating curvaton regime mimics the predictions of Nflation. Some parts of parameter space permitted by power spectrum data are excluded by non-Gaussianity constraints. The recent BICEP2 results [1] require that the inflaton perturbations provide a significant fraction of the total perturbation, ruling out the usual curvaton scenario in which the inflaton perturbations are negligible, though not the admixture regime where both inflaton and curvaton contribute to the spectrum.Comment: 7 pages, 9 figures; v2 matches journal accepted versio

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Section: The Inflating Curvatonsupporting

confidence: 69%

Comprehensive analysis of the simplest curvaton model

2014

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“…We denote N ad = min[N bg , N therm ], where N bg is the time by which super-Hubble coherence of the inflaton condensate is lost, indicated by φ rms > φ . Any significant turning of the system within the field space between the end of inflation and N ad could amplify non-Gaussianities and isocurvature perturbations, thereby threatening the close agreement between predictions in these models and measurements of the CMB [41][42][43][44]. In Fig.…”

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confidence: 95%

Nonlinear Dynamics of Preheating after Multifield Inflation with Nonminimal Couplings

et al. 2019

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We study the post-inflation dynamics of multifield models involving nonminimal couplings using lattice simulations to capture significant nonlinear effects like backreaction and rescattering. We measure the effective equation of state and typical time-scales for the onset of thermalization, which could affect the usual mapping between predictions for primordial perturbation spectra and measurements of anisotropies in the cosmic microwave background radiation. For large values of the nonminimal coupling constants, we find efficient particle production that gives rise to nearly instantaneous preheating. Moreover, the strong single-field attractor behavior that was previously identified persists until the end of preheating, thereby suppressing typical signatures of multifield models. We therefore find that predictions for primordial observables in this class of models retain a close match to the latest observations. * nguyenr@kenyon.edu † jorindev@nikhef.nl ‡ evans@nikhef.nl §

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“…If their amplitude remains unaffected by the bounce physics, they can still be affected by the subsequent phase of (p)reheating, which can change not only the amplitude but also the sign of non-linearity parameters [439,440,480]. Thus, as highlighted above, a thorough understanding of preheating is essential for any comparison of predictions with current and forthcoming high-precision data.…”

Section: Spatial Curvature and Non-gaussianitiesmentioning

confidence: 99%

A critical review of classical bouncing cosmologies

2015

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Given the proliferation of bouncing models in recent years, we gather and critically assess these proposals in a comprehensive review. The PLANCK data shows an unmistakably red, quasi scaleinvariant, purely adiabatic primordial power spectrum and no primary non-Gaussianities. While these observations are consistent with inflationary predictions, bouncing cosmologies aspire to provide an alternative framework to explain them. Such models face many problems, both of the purely theoretical kind, such as the necessity of violating the NEC and instabilities, and at the cosmological application level, as exemplified by the possible presence of shear. We provide a pedagogical introduction to these problems and also assess the fitness of different proposals with respect to the data. For example, many models predict a slightly blue spectrum and must be fine-tuned to generate a red spectral index; as a side effect, large non-Gaussianities often result.We highlight several promising attempts to violate the NEC without introducing dangerous instabilities at the classical and/or quantum level. If primordial gravitational waves are observed, certain bouncing cosmologies, such as the cyclic scenario, are in trouble, while others remain valid. We conclude that, while most bouncing cosmologies are far from providing an alternative to the inflationary paradigm, a handful of interesting proposals have surfaced, which warrant further research. The constraints and lessons learned as laid out in this review might guide future research.

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General analytic predictions of two-field inflation and perturbative reheating

Cited by 25 publications

References 63 publications

Comprehensive analysis of the simplest curvaton model

Comprehensive analysis of the simplest curvaton model

Nonlinear Dynamics of Preheating after Multifield Inflation with Nonminimal Couplings

A critical review of classical bouncing cosmologies

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