Quantization of perturbations in an inflating elastic solid

Sitwell, Michael; Sigurdson, Kris

doi:10.1103/physrevd.89.123509

Cited by 19 publications

(23 citation statements)

References 24 publications

(50 reference statements)

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“…The I 2 (ϕ)F 2 models predict c 2 = c 0 /2, while primordial curvature perturbations sourced by large-scale magnetic fields generate non-vanishing c 0 , c 1 , and c 2 . Quite interestingly, in the proposed "solid inflation" scenario (Endlich et al 2013(Endlich et al , 2014; see also Bartolo et al 2013bBartolo et al , 2014Sitwell & Sigurdson 2014) bispectra similar to Eq. (23) can be generated, in this case with c 2 c 0 (Endlich et al 2013(Endlich et al , 2014.…”

Section: Directional-dependence Motivated By Gauge Fieldsmentioning

confidence: 88%

Planck2015 results

Ade

Aghanim

Arnaud

et al. 2016

A&A

477

256

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The Planck full mission cosmic microwave background (CMB) temperature and E-mode polarization maps are analysed to obtain constraints on primordial non-Gaussianity (NG). Using three classes of optimal bispectrum estimators -separable template-fitting (KSW), binned, and modalwe obtain consistent values for the primordial local, equilateral, and orthogonal bispectrum amplitudes, quoting as our final result from temperature alone f local NL = 2.5 ± 5.7, f equil NL = −16 ± 70, and f ortho NL = −34 ± 33 (68% CL, statistical). Combining temperature and polarization data we obtain f local NL = 0.8 ± 5.0, f equil NL = −4 ± 43, and f ortho NL = −26 ± 21 (68% CL, statistical). The results are based on comprehensive cross-validation of these estimators on Gaussian and non-Gaussian simulations, are stable across component separation techniques, pass an extensive suite of tests, and are consistent with estimators based on measuring the Minkowski functionals of the CMB. The effect of time-domain de-glitching systematics on the bispectrum is negligible. In spite of these test outcomes we conservatively label the results including polarization data as preliminary, owing to a known mismatch of the noise model in simulations and the data. Beyond estimates of individual shape amplitudes, we present model-independent, three-dimensional reconstructions of the Planck CMB bispectrum and derive constraints on early universe scenarios that generate primordial NG, including general single-field models of inflation, axion inflation, initial state modifications, models producing parityviolating tensor bispectra, and directionally dependent vector models. We present a wide survey of scale-dependent feature and resonance models, accounting for the "look elsewhere" effect in estimating the statistical significance of features. We also look for isocurvature NG, and find no signal, but we obtain constraints that improve significantly with the inclusion of polarization. The primordial trispectrum amplitude in the local model is constrained to be g local NL = (−9.0 ± 7.7) × 10 4 (68% CL statistical), and we perform an analysis of trispectrum shapes beyond the local case. The global picture that emerges is one of consistency with the premises of the ΛCDM cosmology, namely that the structure we observe today was sourced by adiabatic, passive, Gaussian, and primordial seed perturbations.

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Section: Directional-dependence Motivated By Gauge Fieldsmentioning

confidence: 88%

Planck2015 results

Ade

Aghanim

Arnaud

et al. 2016

A&A

477

256

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“…2 In addition to the works that we review below, the perturbations in this model where also studied in ref. [8] and ref. [9].…”

Section: Introductionmentioning

confidence: 86%

The expected anisotropy in solid inflation

Bartolo

Peloso

Ricciardone

et al. 2014

J. Cosmol. Astropart. Phys.

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Solid inflation is an effective field theory of inflation in which isotropy and homogeneity are accomplished via a specific combination of anisotropic sources (three scalar fields that individually break isotropy). This results in specific observational signatures that are not found in standard models of inflation: a non-trivial angular dependence for the squeezed bispectrum, and a possibly long period of anisotropic inflation (to drive inflation, the "solid" must be very insensitive to any deformation, and thus background anisotropies are very slowly erased). In this paper we compute the expected level of statistical anisotropy in the power spectrum of the curvature perturbations of this model. To do so, we account for the classical background values of the three scalar fields that are generated on large (superhorizon) scales during inflation via a random walk sum, as the perturbation modes leave the horizon. Such an anisotropy is unavoidably generated, even starting from perfectly isotropic classical initial conditions. The expected level of anisotropy is related to the duration of inflation and to the amplitude of the squeezed bispectrum. If this amplitude is close to its current observational limit (so that one of the most interesting predictions of the model can be observed in the near future), we find that a level of statistical anisotropy > ∼ 3% in the power spectrum is to be expected, if inflation lasted > ∼ 20 − 30 e-folds more than the final 50 − 60 efolds required to generare the CMB modes. We also comment and point out various similarities between solid inflation and models of inflation where a suitable coupling of the inflaton to a vector kinetic term F 2 gives frozen and scale invariant vector perturbations on superhorizon scales.

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“…But there is also the possibility of inflationary systems that break also spatial diffeomorphism invariance, like inflationary vector fields [12] (see e.g. [13,14] for review), or alternatively a set of scalar fields obeying special internal symmetries that acquire space-dependent vacuum expectation values, as in the case of solid/elastic inflation [15,16] (see also [17,18]). Motivated by these considerations, we find interesting to exploit the EFT of inflation to explore more general options than those studied so far, also considering the effects of slightly broken spatial diffeomorphism invariance.…”

Section: Introductionmentioning

confidence: 99%

Breaking discrete symmetries in the effective field theory of inflation

Cannone

Gong

Tasinato

2015

J. Cosmol. Astropart. Phys.

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We study the phenomenon of discrete symmetry breaking during the inflationary epoch, using a model-independent approach based on the effective field theory of inflation. We work in a context where both time reparameterization symmetry and spatial diffeomorphism invariance can be broken during inflation. We determine the leading derivative operators in the quadratic action for fluctuations that break parity and time-reversal. Within suitable approximations, we study their consequences for the dynamics of linearized fluctuations. Both in the scalar and tensor sectors, we show that such operators can lead to new direction-dependent phases for the modes involved. They do not affect the power spectra, but can have consequences for higher correlation functions. Moreover, a small quadrupole contribution to the sound speed can be generated.

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Quantization of perturbations in an inflating elastic solid

Cited by 19 publications

References 24 publications

Planck2015 results

Planck2015 results

The expected anisotropy in solid inflation

Breaking discrete symmetries in the effective field theory of inflation

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