Observable signatures of inflaton decays

Battefeld, Diana; Battefeld, Thorsten; Giblin, John T.; Pease, Evan K.

doi:10.1088/1475-7516/2011/02/024

Cited by 18 publications

(19 citation statements)

References 92 publications

(314 reference statements)

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“…xl Which would correspond to the case λ = 1 -see the figure in Appendix B.3 for observationally relevant particle production for smaller values of λ. xli See also [153] for a related study in a fully multi-field context.…”

Section: Light Particle Content and Particle Productionmentioning

confidence: 99%

Features and new physical scales in primordial observables: Theory and observation

Chluba

Hamann

Patil

2015

Int. J. Mod. Phys. D

212

233

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June 22, 20152 All cosmological observations to date are consistent with adiabatic, Gaussian and nearly scale invariant initial conditions. These findings provide strong evidence for a particular symmetry breaking pattern in the very early universe (with a close to vanishing order parameter, ), widely accepted as conforming to the predictions of the simplest realizations of the inflationary paradigm. However, given that our observations are only privy to perturbations, in inferring something about the background that gave rise to them, it should be clear that many different underlying constructions project onto the same set of cosmological observables. Features in the primordial correlation functions, if present, would offer a unique and discriminating window onto the parent theory in which the mechanism that generated the initial conditions is embedded. In certain contexts, simple linear response theory allows us to infer new characteristic scales from the presence of features that can break the aforementioned degeneracies among different background models, and in some cases can even offer a limited spectroscopy of the heavier degrees of freedom that couple to the inflaton. In this review, we offer a pedagogical survey of the diverse, theoretically well grounded mechanisms which can imprint features into primordial correlation functions in addition to reviewing the techniques one can employ to probe observations. These observations include cosmic microwave background anisotropies and spectral distortions as well as the matter two and three point functions as inferred from large-scale structure and potentially, 21 cm surveys.

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Section: Light Particle Content and Particle Productionmentioning

confidence: 99%

Features and new physical scales in primordial observables: Theory and observation

Chluba

Hamann

Patil

2015

Int. J. Mod. Phys. D

212

233

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“…An inflaton potential with a step was studied in the Einstein frame [45] (see also [46]) and shown to result in oscillations in the power spectra. Fading oscillatory features in the primordial scalar power spectrum can also occur from jumps in the potential [47][48][49][50][51], particle production during inflation [52][53][54] or turns in the inflaton trajectory in the landscape of heavy fields [55][56][57][58][59]. For a discussion of observed features in the primordial power spectrum, see for instance [60] and references therein.…”

Section: Introductionmentioning

confidence: 99%

Effect of transitions in the Planck mass during inflation on primordial power spectra

et al. 2014

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We study the effect of sudden transitions in the effective Planck mass during inflation on primordial power spectra. Specifically, we consider models in which this variation results from the non-minimal coupling of a Brans-Dicke type scalar field. We find that the scalar power spectra develop features at the scales corresponding to those leaving the horizon during the transition. In addition, we observe that the tensor perturbations are largely unaffected, so long as the variation of the Planck mass is below the percent level. Otherwise, the tensor power spectra exhibit damped oscillations over the same scales. Due to significant features in the scalar power spectra, the tensor-to-scalar ratio r shows variation over the corresponding scales. Thus, by studying the spectra of both scalar and tensor perturbations, one can constrain sudden but small variations of the Planck mass during inflation. We illustrate these effects with a number of benchmark singleand two-field models. In addition, we comment on their implications and the possibility to alleviate the tension between the observations of the tensor-to-scalar ratio performed by the Planck and BICEP2 experiments.

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“…Plugging the solutions in (3.39) and (4.22) into the matching conditions, we can calculate the Bogoliubov coefficients to Since the details of the excitation mechanism, and in fact the effect of the heavy field at the perturbed level, are cut out in the sudden transition approximation, we deduce that the above Bogoliubov coefficients are a generic feature. Not surprisingly, the same coefficents were found in [65] where inflatons in multi-field brane/anti-brane inflation decayed during inflation as the associated pairs of branes annihilate, leaving some radiation as decay products (see also [66,[71][72][73]). …”

Section: Sudden Transition Approximationmentioning

confidence: 64%

“…2. We follow [61,65,66] to compute the resulting power-spectrum in the sudden transition approximation, see Sec. 2.3.…”

Section: Introductionmentioning

confidence: 99%

A universal bound on excitations of heavy fields during inflation

Battefeld

Freitas

2014

J. Cosmol. Astropart. Phys.

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Abstract. We discuss a universal bound on any excitation of heavy fields during inflation: the ratio of the heavy field's energy density to the one driving inflation must be less than the maximally allowed relative amplitude of oscillations in the power-spectrum (ρ h /ρ I 0.01 according to PLANCK). This bound can be traced back to the sudden change of the equation of state parameter across the excitation event.We employ a sudden transition approximation at the perturbed level, which has been used before in different settings; we check its validity by comparison to the full multi-field result in a concrete case study involving a sudden mass change of an inflaton.

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Observable signatures of inflaton decays

Cited by 18 publications

References 92 publications

Features and new physical scales in primordial observables: Theory and observation

Features and new physical scales in primordial observables: Theory and observation

Effect of transitions in the Planck mass during inflation on primordial power spectra

A universal bound on excitations of heavy fields during inflation

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