Isocurvature Fluctuations of the M-theory Axion in a Hybrid Inflation Model

Kanazawa, Takeshi; Kawasaki, Masahiro; Sugiyama, Naoshi; Yanagida, Tsutomu T.

doi:10.1143/ptp.100.1055

Cited by 11 publications

(8 citation statements)

References 16 publications

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“…The properties of axion, such as the decay constant and its couplings to ordinary matters are constrained from various observations of astrophysical and cosmological phenomena [29,30]. In inflationary universe, the axion field has CDM isocurvature perturbations [31,32,33,34,35,36,37,38] and they are constrained from observations of CMB and LSS [39,40]. Firstly, we briefly review how the axion becomes CDM and its isocurvature fluctuation arises in the early universe.…”

Section: Constraints On Axion Isocurvature Perturbation and Inflation...mentioning

confidence: 99%

Cosmological Constraints on Isocurvature and Tensor Perturbations

Kawasaki

Sekiguchi

2008

Progress of Theoretical Physics

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We investigate cosmological constraints on primordial isocurvature and tensor perturbations, using recent observations of the cosmic microwave background and the large scale structure. We find that present observations are consistent with purely adiabatic initial conditions for the structure formation under any priors on correlations of isocurvature modes, and upper limits on the contribution of isocurvature and tensor perturbations are presented. We also apply the obtained constraints to some specific theoretical models, axion isocurvature perturbation models and curvaton models, and give some implications for theoretical models.Comment: 24 pages, 8 figure

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Section: Constraints On Axion Isocurvature Perturbation and Inflation...mentioning

confidence: 99%

Cosmological Constraints on Isocurvature and Tensor Perturbations

Kawasaki

Sekiguchi

2008

Progress of Theoretical Physics

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“…The result is that H is as large as H ∼ O(10 11−12 GeV), with the reasonable values of the coupling constants 10 −2 < ∼ κ, β < ∼ 10 −1 [6] (see Fig. 9).…”

Section: A Hybrid Inflation Modelmentioning

confidence: 66%

“…( 19) F a θ a ∼ 10 12 GeV, which is the canonical value for axionic dark matter without late-time entropy production. 6…”

Section: B New Inflation Modelmentioning

confidence: 99%

Observational Implications of Axionic Isocurvature Fluctuations

Kanazawa

Kawasaki

Sugiyama

et al. 1999

Progress of Theoretical Physics

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The axion is the most attractive candidate to solve the strong CP problem in QCD. If it exists, the inflationary universe produces axion fluctuations which are mixtures of isocurvature and adiabatic fluctuations in general. We investigate how large isocurvature fluctuations are allowed or favored in order to explain observations of the large scale structure of the present universe. Generic flat universe models with mixed (isocurvature + adiabatic) density fluctuations are studied. It is found that the observations are consistent with the mixed fluctuation model if the ratio \alpha of the power spectrum of isocurvature fluctuations to that of adiabatic fluctuations is less than \sim 0.1. In particular, the mixed fluctuation model with \alpha \sim 0.05, total matter density \Omega_{0} =0.4, and Hubble parameter H_0=70 km/s/Mpc gives a very good fit to the observational data. Since the height of the acoustic peak in the angular power spectrum of the cosmic microwave background (CMB) radiation decreases significantly when the isocurvature fluctuations are present, the mixed fluctuation model can be tested in future satellite experiments. Ratios of the amplitude at the peak location to that at the COBE normalization scale for various models are given. Furthermore, we also obtain the amplitude of isocurvature fluctuations as a function of axion parameters and the Hubble parameter during the inflation. We discuss the axion fluctuations in some realistic inflation models and find that a significant amount of the isocurvature fluctuations are naturally produced.Comment: 31 pages (RevTeX file), the final version to appear in Prog. Theor. Phy

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“…However, the weakness of the second acoustic peak at , arising from the subsequent first rarefaction of the acoustic wave on the last scattering horizon, has provoked considerable speculation as to the additional freedom that could be added to the concordance cold dark matter (CDM) model (matter density parameter , flatness being restored by a cosmological constant , Hubble parameter , baryon density parameter to accommodate such an effect. Ideas that have been proposed include enhancement of the baryon fraction (White, Scott & Pierpaoli 2000; Lange et al 2001), a large neutrino asymmetry (Lesgourgues & Peloso 2000), delay of recombination (Hu & Peebles 2000), an admixture of a component of cosmological defects (Bouchet et al 2000) and models employing double inflation in supergravity (Kanazawa et al 2000).…”

Section: Introductionmentioning

confidence: 99%

Bumpy power spectra and T/T

Griffiths¹,

Silk²,

Zaroubi

2001

Monthly Notices of the Royal Astronomical Society

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With the recent publication of the measurements of the radiation angular power spectrum from the BOOMERanG‐98 Antarctic flight, it has become apparent that the currently favoured spatially flat cold dark matter model (matter density parameter Ωm=0.3, flatness being restored by a cosmological constant ΩΛ=0.7, Hubble parameter h=0.65, baryon density parameter Ωbh2=0.02) no longer provides a good fit to the data. We describe a phenomenological approach to resurrecting this paradigm. We consider a primordial power spectrum which incorporates a bump, arbitrarily placed at kb and characterized by a Gaussian in log k of standard deviation σb and amplitude Ab, which is superimposed on to a scale‐invariant power spectrum. We generate a range of theoretical models that include a bump at scales consistent with cosmic microwave background (CMB) and large‐scale structure observations, and perform a simple χ2 test to compare our models with the COBE Differential Microwave Radiometer (DMR) data and the recently published BOOMERanG‐98 and MAXIMA‐1 data. Unlike models that include a high baryon content, our models predict a low third acoustic peak. We find that low ℓ observations (20<ℓ<200) are a critical discriminant of the bumps because the transfer function has a sharp cut‐off on the high ℓ side of the first acoustic peak. Current galaxy redshift survey data suggest that excess power is required at a scale around 100 Mpc, corresponding to kb∼0.05 h Mpc−1. For the concordance model, use of a bump‐like feature to account for this excess is not consistent with the constraints imposed by recent CMB data. We note that models with an appropriately chosen break in the power spectrum provide an alternative model that can give distortions similar to those reported in the automated plate measurement (APM) survey as well as consistency with the CMB data. We prefer, however, to discount the APM data in favour of the less biased decorrelated linear power spectrum recently constructed from the Point Source Catalogue Redshift (PSCz) redshift survey. We show that the concordance cosmology can be resurrected using our phenomenological approach and that our best‐fitting model is in agreement with the PSCz observations.

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Isocurvature Fluctuations of the M-theory Axion in a Hybrid Inflation Model

Cited by 11 publications

References 16 publications

Cosmological Constraints on Isocurvature and Tensor Perturbations

Cosmological Constraints on Isocurvature and Tensor Perturbations

Observational Implications of Axionic Isocurvature Fluctuations

Bumpy power spectra and T/T

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