The Inflationary Perturbation Spectrum

Habib, Salman; Heitmann, Katrin; Jungman, Gerard; Molina-Parı́s, Carmen

doi:10.1103/physrevlett.89.281301

Cited by 82 publications

(143 citation statements)

References 20 publications

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“…Although the analytic calculation does not yet provide an exact match to the exact numerical solution, it does capture the characteristic oscillations that are generated in the spectrum [20,49] and provides considerable insight into the physics behind this phenomenon. There may be scope for developing more accurate calculational techniques in this context [56,57]. It should be of course borne in mind that caution is required in using the standard calculational framework for the inflationary metric perturbation for the case of a time-dependent effective potential [62,63].…”

Section: Discussionmentioning

confidence: 99%

Multiple inflation and the WMAP “glitches”

2004

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Observations of anisotropies in the cosmic microwave background by the Wilkinson Microwave Anisotropy Probe suggest the possibility of oscillations in the primordial curvature perturbation. Such deviations from the usually assumed scale-free spectrum were predicted in the multiple inflation model wherein 'flat direction' fields undergo rapid phase transitions due to the breaking of supersymmetry by the large vacuum energy driving inflation. This causes sudden changes in the mass of the (gravitationally coupled) inflaton and interrupts its slow roll. We calculate analytically the resulting modifications to the curvature perturbation and demonstrate how the oscillations arise.

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Section: Discussionmentioning

confidence: 99%

Multiple inflation and the WMAP “glitches”

2004

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“…In this appendix we show how the procedure used in this paper to match solutions which are good approximations in different ranges of k space includes the recent application of the WKB method in the context of cosmological perturbations [34,35]. In this paper we have chosen a Bessel form in Eq.…”

Section: Appendix A: Comparison With Wkb Methodsmentioning

confidence: 99%

Energy-momentum tensor of cosmological fluctuations during inflation

et al. 2004

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We study the renormalized energy-momentum tensor (EMT) of cosmological scalar fluctuations during the slow-rollover regime for chaotic inflation with a quadratic potential and find that it is characterized by a negative energy density which grows during slow-rollover. We also approach the back-reaction problem as a second-order calculation in perturbation theory finding no evidence that the back-reaction of cosmological fluctuations is a gauge artifact. In agreement with the results for the EMT, the average expansion rate is decreased by the back-reaction of cosmological fluctuations.

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“…(4.22) was used. In terms of R the super-momentum constraint (4.9) can be written in the form, 26) which reduces to R ′ = HS on all scales in the relativistic limit λ → 1. Thus, in the slow-roll approximations and neglecting the spatial gradients on large scales, we obtain the same conclusion as that given in [34], namely, the comoving curvature perturbation has two modes on large scales, a constant mode and a rapidly decaying mode, given by…”

Section: Comoving Curvature Perturbationmentioning

confidence: 99%

“…To calculate the spectra and indices of scalar and tensor perturbations with the slow-roll approximations, we shall use the uniform approximation, proposed recently in [26], and applied to the studies of tensor perturbations in the HL theory without the U(1) symmetry in [35,36]. We shall closely follow the treatment presented in [36].…”

Section: Power Spectra and Indices Of Scalar And Tensor Perturbatmentioning

confidence: 99%

Inflation in general covariant theory of gravity

Huang

Wang

2012

J. Cosmol. Astropart. Phys.

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In this paper, we study inflation in the framework of the nonrelativistic general covariant theory of the Hořava-Lifshitz gravity with the projectability condition and an arbitrary coupling constant λ. We find that the Friedmann-Robterson-Walker (FRW) universe is necessarily flat in such a setup. We work out explicitly the linear perturbations of the flat FRW universe without specifying to a particular gauge, and find that the perturbations are different from those obtained in general relativity, because of the presence of the high-order spatial derivative terms. Applied the general formulas to a single scalar field, we show that in the sub-horizon regions, the metric and scalar field are tightly coupled and have the same oscillating frequencies. In the super-horizon regions, the perturbations become adiabatic, and the comoving curvature perturbation is constant. We also calculate the power spectra and indices of both the scalar and tensor perturbations, and express them explicitly in terms of the slow roll parameters and the coupling constants of the high-order spatial derivative terms. In particular, we find that the perturbations, of both scalar and tensor, are almost scale-invariant, and, with some reasonable assumptions on the coupling coefficients, the spectrum index of the tensor perturbation is the same as that given in the minimum scenario in GR, whereas the index for scalar perturbation in general depends on λ and is different from the standard GR value. The ratio of the scalar and tensor power spectra depends on the high-order spatial derivative terms, and can be different from that of GR significantly.

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The Inflationary Perturbation Spectrum

Cited by 82 publications

References 20 publications

Multiple inflation and the WMAP “glitches”

Multiple inflation and the WMAP “glitches”

Energy-momentum tensor of cosmological fluctuations during inflation

Inflation in general covariant theory of gravity

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