Minimal modifications of the primordial power spectrum from an adiabatic short distance cutoff

Niemeyer, J. C.; Renaud, Philippe; Campo, David Gutiérrez Díaz del

doi:10.1103/physrevd.66.083510

Cited by 73 publications

(87 citation statements)

References 29 publications

(40 reference statements)

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“…These features generally consist of superimposed oscillations in the CMB multipole moments C ℓ . They could originate either from trans-Planckian effects taking place in the early universe [3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32] or from other phenomena, for instance of the type of those investigated in Refs. [33,34,35,36,37,38].…”

Section: Introductionmentioning

confidence: 99%

Exploring the superimposed oscillations parameter space

Martin

Ringeval

2005

J. Cosmol. Astropart. Phys.

102

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Abstract.The space of parameters characterizing an inflationary primordial power spectrum with small superimposed oscillations is explored using Monte Carlo methods. The most interesting region corresponding to high frequency oscillations is included in the analysis. The oscillations originate from some new physics taking place at the beginning of the inflationary phase and characterized by the new energy scale M c . It is found that the standard slow-roll model remains the most probable one given the first year WMAP data. At the same time, the oscillatory models better fit the data on average, which is consistent with previous works on the subject. This is typical of a situation where volume effects in the parameter space play a significant role. Then, we find the amplitude of the oscillations to be less than 22% of the mean amplitude and the new scale M c to be such that H/M c < 6.6 × 10 −4 at 1σ level, where H is the scale of inflation.PACS numbers: 98.80.Cq, 98.70.Vc

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Section: Introductionmentioning

confidence: 99%

Exploring the superimposed oscillations parameter space

Martin

Ringeval

2005

J. Cosmol. Astropart. Phys.

102

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“…Standard EFT arguments give n 2 [22] unless boundary terms are added [23][24][25][26][27][28][29][30]. The latter may yield n 1 and seem to reproduce the effects of an unconventional initial state or nonadiabatic evolution [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47]. However, the main issue remains the conspicuously small value of H=M.…”

Section: Introduction: Seeing Strings In Cosmologymentioning

confidence: 99%

Stringy effects during inflation and reheating

2006

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We consider inflationary cosmology in the context of string compactifications with multiple throats. In scenarios where the warping differs significantly between throats, string and Kaluza-Klein physics can generate potentially observable corrections to the cosmology of inflation and reheating. First we demonstrate that a very low string scale in the ground state compactification is incompatible with a high Hubble scale during inflation, and we propose that the compactification geometry is altered during inflation. In this configuration, the lowest scale is just above the Hubble scale, which is compatible with the effective field theory but still leads to potentially observable cosmic microwave background corrections. Also in the appropriate region of parameter space, we find that reheating leads to a phase of long open strings in the standard model sector (before the usual radiation-dominated phase). We sketch the cosmology of the long string phase and we discuss possible observational consequences.

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“…There are thus two ways of detecting the new physics in the perturbation spectrum. First, if the correction contains a sharply defined phase factor which is a function of H p /Λ, an oscillatory feature extending over a wide range of the power spectrum may be produced [4,5,6]. Second, even if oscillations are absent, there is still a possibility that the largest scales we observe today correspond to sufficiently large H p /Λ that the new physics lead to a distinctive suppression or enhancement of the low-l power spectrum at a detectable level.…”

Section: Introductionmentioning

confidence: 99%

“…The power spectrum of φ is given by the Fourier transform of the two-point correlation function at equal times (6) where · and { · , · } denote the quantum expectation value and the anticommutator, respectively.…”

Section: A the Modelmentioning

confidence: 99%

“…In the simplest of these models, scalar or tensor perturbation modes are prescribed to be created in their adiabatic vacuum at some fixed initial time, where the initial conditions are specified either on a spacelike surface common to all modes [8], or when the physical momentum P = p/a of each mode with comoving momentum p satisfies P = Λ [4,5,6]. These models predict a spectrum with superimposed oscillations whose amplitude is a power of H p /Λ which depends on the degree of non-adiabaticity of the initial state.…”

Section: Introductionmentioning

confidence: 99%

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Inflationary spectra from Lorentz violating dissipative models

et al. 2008

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The sensitivity of inflationary spectra to initial conditions is addressed in the context of a phenomenological model that breaks Lorentz invariance by dissipative effects above some threshold energy Λ. These effects are obtained dynamically by coupling the fluctuation modes to extra degrees of freedom which are unobservable below Λ. Because of the strong dissipative effects in the early propagation, only the state of the extra degrees of freedom is relevant for the power spectrum. If this state is the ground state, and if Λ is much larger than the Hubble scale H, the standard spectrum is recovered. Using analytical and numerical methods, we calculate the modifications for a large class of dissipative models. For all of these, we show that the leading modification (in an expansion in H/Λ) is linear in the decay rate evaluated at horizon exit, and that high frequency superimposed oscillations are not generated. The modification is negative when the decay rate decreases slower than the cube of H, which means that there is a loss of power on the largest scales.

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Minimal modifications of the primordial power spectrum from an adiabatic short distance cutoff

Cited by 73 publications

References 29 publications

Exploring the superimposed oscillations parameter space

Exploring the superimposed oscillations parameter space

Stringy effects during inflation and reheating

Inflationary spectra from Lorentz violating dissipative models

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