Can a relic cosmological constant reconcile inflationary predictions with the observations?

Vittorio, N.; Silk, J. K.

doi:10.1086/184545

Cited by 24 publications

(12 citation statements)

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“…We first note that the present‐day horizon size for flat models is well approximated by (Vittorio & Silk 1985) (The distance to last scattering is ∼2 per cent smaller than the above because of the finite redshift of last scattering.) Therefore, if we increase Ω m while keeping ω m fixed, the shape and relative heights of the CMB peaks are preserved but the peaks move slowly rightwards (increasing ℓ) proportional to Ω 0.1 m .…”

Section: The Horizon Angle Degeneracymentioning

confidence: 94%

Parameter constraints for flat cosmologies from cosmic microwave background and 2dFGRS power spectra

Percival

Sutherland

Peacock

et al. 2002

Monthly Notices of the Royal Astronomical Society

298

203

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We constrain flat cosmological models with a joint likelihood analysis of a new compilation of data from the cosmic microwave background (CMB) and from the 2dF Galaxy Redshift Survey (2dFGRS). Fitting the CMB alone yields a known degeneracy between the Hubble constant h and the matter density Ωm, which arises mainly from preserving the location of the peaks in the angular power spectrum. This ‘horizon‐angle degeneracy’ is considered in some detail and is shown to follow the simple relation Ωmh3.4= constant. Adding the 2dFGRS power spectrum constrains Ωmh and breaks the degeneracy. If tensor anisotropies are assumed to be negligible, we obtain values for the Hubble constant of h= 0.665 ± 0.047, the matter density Ωm= 0.313 ± 0.055, and the physical cold dark matter and baryon densities Ωch2= 0.115 ± 0.009, Ωbh2= 0.022 ± 0.002 (standard rms errors). Including a possible tensor component causes very little change to these figures; we set an upper limit to the tensor‐to‐scalar ratio of r < 0.7 at a 95 per cent confidence level. We then show how these data can be used to constrain the equation of state of the vacuum, and find w < −0.52 at 95 per cent confidence. The preferred cosmological model is thus very well specified, and we discuss the precision with which future CMB data can be predicted, given the model assumptions. The 2dFGRS power‐spectrum data and covariance matrix, and the CMB data compilation used here, are available from http://www.roe.ac.uk/~wjp/.

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Section: The Horizon Angle Degeneracymentioning

confidence: 94%

Parameter constraints for flat cosmologies from cosmic microwave background and 2dFGRS power spectra

Percival

Sutherland

Peacock

et al. 2002

Monthly Notices of the Royal Astronomical Society

298

203

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“…There is no obvious property that would have prevented us from asking about the Universe if we lived in a civilization several billion years into the past or the future. If we define some parameters to be simply the quantities at the time we measure them, 9 then their values will be partly accidental in the sense that the epoch we are living at contains some randomness. This may seem like a fairly ineffectual kind of stochasticity, but it has the virtue of being easy to understand, and undeniably real.…”

Section: Three Levels Of Stochasticitymentioning

confidence: 99%

“…By the end of the 1980s the addition of a cosmological constant was known to give better fits to the available data (see, for example, refs. [8][9][10].…”

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confidence: 99%

The standard cosmological model

Scott

2006

Can. J. Phys.

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The Standard Model of Particle Physics (SMPP) is an enormously successful description of high-energy physics, driving ever more precise measurements to find "physics beyond the standard model", as well as providing motivation for developing more fundamental ideas that might explain the values of its parameters. Simultaneously, a description of the entire three-dimensional structure of the present-day Universe is being built up painstakingly. Most of the structure is stochastic in nature, being merely the result of the particular realization of the "initial conditions" within our observable Universe patch. However, governing this structure is the Standard Model of Cosmology (SMC), which appears to require only about a dozen parameters. Cosmologists are now determining the values of these quantities with increasing precision to search for "physics beyond the standard model", as well as trying to develop an understanding of the more fundamental ideas that might explain the values of its parameters. Although it is natural to see analogies between the two Standard Models, some intrinsic differences also exist, which are discussed here. Nevertheless, a truly fundamental theory will have to explain both the SMPP and SMC, and this must include an appreciation of which elements are deterministic and which are accidental. Considering different levels of stochasticity within cosmology may make it easier to accept that physical parameters in general might have a nondeterministic aspect. PACS Nos.: 98.80.−k, 98.80.Bp, 98.80.Es, 12.60.−i Résumé : Le modèle standard de la physique des particules (SMPP) a connu beaucoup de succès en physique de haute énergie, invitant à des mesures encore plus précises pour identifier une « physique au delà du modèle standard » et fournissant des incitatifs pour développer des idées encore plus fondamentales qui pourraient expliquer la valeur de ces paramètres. Nous peinons actuellement à développer une description de l'entière structure de l'espace 3-D de l'actuel univers. Cette structure est majoritairement stochastique, étant le résultat de l'évolution de « conditions initiales » à l'intérieur de notre portion observable de l'univers. Cependant, gérant cette structure, se trouve le modèle standard de la cosmologie (SMC), qui a besoin d'environ 12 paramètres. Les cosmologistes sont occupés à déterminer la valeur de ces paramètres avec une précision croissante, de façon à sonder une « physique au delà du modèle standard », aussi bien qu'à tenter de développer des idées plus fondamentales qui expliqueraient ces valeurs. Même s'il est facile de voir une analogie entre ces deux modèles standard, nous examinons certaines de leurs différences. Néanmoins, une théorie vraiment fondamentale devra expliquer simultanément SMPP et SMC et ceci doit permettre de séparer les éléments qui sont déterministes de ceux qui sont

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“…Among others, many recent observations seem to favor a low-density universe, which conflicts with the prediction of the inflationary scenario unless a cosmological constant is introduced. In fact, it has been pointed out that a flat universe with cosmological constant is not only less constrained by cosmic background radiation (CBR) anisotropies (Vittorio and Silk 1985;Holtzman 1989;Sugiyama, Gouda, and Sasaki 1990) but also is most favored observationally (Fukugita et af. 1990).…”

Section: Introductionmentioning

confidence: 99%

Large‐scale Anisotropy of Cosmic Background Radiation in Open Cosmological Models

Gouda

Sugiyama

Sasaki

1991

Annals of the New York Academy of Sciences

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Can a relic cosmological constant reconcile inflationary predictions with the observations?

Cited by 24 publications

References 0 publications

Parameter constraints for flat cosmologies from cosmic microwave background and 2dFGRS power spectra

Parameter constraints for flat cosmologies from cosmic microwave background and 2dFGRS power spectra

The standard cosmological model

Large‐scale Anisotropy of Cosmic Background Radiation in Open Cosmological Models

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