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Title: Observational test of holographic inflation

Abstract

Observational consequences of inflationary cosmology in the holographic dual of the Randall-Sundrum type II braneworld scenario, as motivated by the anti-de Sitter/conformal field theory correspondence, are investigated. High energy corrections to the standard four-dimensional Friedmann equation induce a corresponding modification to the form of the single-field inflationary consistency equation based on Einstein gravity. The degree of departure from the standard expression is determined by the ratio, r, of the primordial tensor and scalar perturbation amplitudes and the coefficient, c, of the conformal anomaly in the dual gauge theory. It is found that a necessary condition for detecting such a correction with the next generation of cosmic microwave background (CMB) polarization experiments is that r{>=}0.06. The bound is tightened to r>0.3 for values of the central charge that are compatible with known compactifications of type IIB string theory as parametrized in terms of F-theory compactification on Calabi-Yau four-folds. This is close to the present upper bounds inferred from combined observations of the CMB anisotropy power spectrum and high redshift surveys. We conclude that if such modifications to the inflationary consistency equation are to be observable, the gravitational wave background should be detected in the near future. A further consequence of themore » nonstandard dynamics at high energies is that the initial state of the universe is a quiescent singularity with a finite density and pressure.« less

Authors:
;  [1]
  1. Astronomy Unit, School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London, E1 4NS (United Kingdom)
Publication Date:
OSTI Identifier:
20795708
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 73; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevD.73.023516; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AMPLITUDES; ANISOTROPY; COMPACTIFICATION; CONFORMAL INVARIANCE; CORRECTIONS; COSMIC RADIATION; COSMOLOGY; DE SITTER GROUP; DENSITY; DISTURBANCES; FIELD EQUATIONS; GAUGE INVARIANCE; GRAVITATION; GRAVITATIONAL WAVES; INFLATION; POLARIZATION; QUANTUM FIELD THEORY; RADIOWAVE RADIATION; RELICT RADIATION; SCALARS; SINGULARITY; STANDARDS; STRING MODELS; TENSORS; UNIVERSE

Citation Formats

Lidsey, James E., and Seery, David. Observational test of holographic inflation. United States: N. p., 2006. Web. doi:10.1103/PHYSREVD.73.0.
Lidsey, James E., & Seery, David. Observational test of holographic inflation. United States. doi:10.1103/PHYSREVD.73.0.
Lidsey, James E., and Seery, David. Sun . "Observational test of holographic inflation". United States. doi:10.1103/PHYSREVD.73.0.
@article{osti_20795708,
title = {Observational test of holographic inflation},
author = {Lidsey, James E. and Seery, David},
abstractNote = {Observational consequences of inflationary cosmology in the holographic dual of the Randall-Sundrum type II braneworld scenario, as motivated by the anti-de Sitter/conformal field theory correspondence, are investigated. High energy corrections to the standard four-dimensional Friedmann equation induce a corresponding modification to the form of the single-field inflationary consistency equation based on Einstein gravity. The degree of departure from the standard expression is determined by the ratio, r, of the primordial tensor and scalar perturbation amplitudes and the coefficient, c, of the conformal anomaly in the dual gauge theory. It is found that a necessary condition for detecting such a correction with the next generation of cosmic microwave background (CMB) polarization experiments is that r{>=}0.06. The bound is tightened to r>0.3 for values of the central charge that are compatible with known compactifications of type IIB string theory as parametrized in terms of F-theory compactification on Calabi-Yau four-folds. This is close to the present upper bounds inferred from combined observations of the CMB anisotropy power spectrum and high redshift surveys. We conclude that if such modifications to the inflationary consistency equation are to be observable, the gravitational wave background should be detected in the near future. A further consequence of the nonstandard dynamics at high energies is that the initial state of the universe is a quiescent singularity with a finite density and pressure.},
doi = {10.1103/PHYSREVD.73.0},
journal = {Physical Review. D, Particles Fields},
number = 2,
volume = 73,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}
  • We study in detail the power spectra of scalar and tensor perturbations generated during inflation in loop quantum cosmology (LQC). After clarifying in a novel quantitative way how inverse-volume corrections arise in inhomogeneous settings, we show that they can generate large running spectral indices, which generally lead to an enhancement of power at large scales. We provide explicit formulæ for the scalar/tensor power spectra under the slow-roll approximation, by taking into account corrections of order higher than the runnings. Via a standard analysis, we place observational bounds on the inverse-volume quantum correction δ∝a{sup −σ} (σ > 0, a is themore » scale factor) and the slow-roll parameter ε{sub V} for power-law potentials as well as exponential potentials by using the data of WMAP 7yr combined with other observations. We derive the constraints on δ for two pivot wavenumbers k{sub 0} for several values of δ. The quadratic potential can be compatible with the data even in the presence of the LQC corrections, but the quartic potential is in tension with observations. We also find that the upper bounds on δ(k{sub 0}) for given σ and k{sub 0} are insensitive to the choice of the inflaton potentials.« less
  • In this work, we consider the cosmological constraints on the holographic Ricci dark energy proposed by Gao et al.[Phys. Rev. D 79, 043511 (2009)], by using the observational data currently available. The main characteristic of holographic Ricci dark energy is governed by a positive numerical parameter {alpha} in the model. When {alpha}<1/2, the holographic Ricci dark energy will exhibit a quintomlike behavior; i.e., its equation of state will evolve across the cosmological-constant boundary w=-1. The parameter {alpha} can be determined only by observations. Thus, in order to characterize the evolving feature of dark energy and to predict the fate ofmore » the Universe, it is of extraordinary importance to constrain the parameter {alpha} by using the observational data. In this paper, we derive constraints on the holographic Ricci dark energy model from the latest observational data including the Union sample of 307 type Ia supernovae, the shift parameter of the cosmic microwave background given by the five-year Wilkinson Microwave Anisotropy Probe observations, and the baryon acoustic oscillation measurement from the Sloan Digital Sky Survey. The joint analysis gives the best-fit results (with 1{sigma} uncertainty): {alpha}=0.359{sub -0.025}{sup +0.024} and {omega}{sub m0}=0.318{sub -0.024}{sup +0.026}. That is to say, according to the observations, the holographic Ricci dark energy takes on the quintom feature. Finally, in light of the results of the cosmological constraints, we discuss the issue of the scalar-field dark energy reconstruction, based on the scenario of the holographic Ricci vacuum energy.« less
  • In this paper, the holographic dark energy models with the new infrared cutoff for both the flat case and the nonflat case are confronted with the combined constraints of current cosmological observations: type Ia supernovae, baryon acoustic oscillations, current cosmic microwave background, and the observational Hubble data. By utilizing the Markov chain Monte Carlo method, we obtain the best fit values of the parameters with 1{sigma}, 2{sigma} errors in the flat model: {Omega}{sub b}h{sup 2}=0.0230{sub -0.0010-0.0014}{sup +0.0008+0.0012}, {alpha}=0.9788{sub -0.0927-0.1249}{sup +0.1297+0.1354}, {beta}=0.4739{sub -0.0723-0.0984}{sup +0.0793+0.1055}, {Omega}{sub de0}=0.7869{sub -0.0304-0.0455}{sup +0.0291+0.0370}, {Omega}{sub m0}=0.2131{sub -0.0291-0.0370}{sup +0.0304+0.0455}, H{sub 0}=70.46{sub -2.97-4.02}{sup +2.82+3.89}. In the nonflat model, themore » constraint results are found in 1{sigma}, 2{sigma} regions: {Omega}{sub b}h{sup 2}=0.0229{sub -0.0010-0.0014}{sup +0.0010+0.0013}, {Omega}{sub k}=0.0014{sub -0.0597-0.0743}{sup +0.0604+0.0604}, {alpha}=0.9637{sub -0.2840-0.3333}{sup +0.2291+0.2894}, {beta}=0.4712{sub -0.0756-0.0961}{sup +0.1412+0.1703}, {Omega}{sub de0}=0.7829{sub -0.2130-0.2386}{sup +0.1588+0.1901}, {Omega}{sub m0}=0.2157{sub -0.1012-0.1241}{sup +0.1562+0.1800}, H{sub 0}=70.64{sub -3.32-4.45}{sup +2.74+3.52}. In the best fit holographic dark energy models, the equation of state of dark energy and the deceleration parameter at present are characterized by w{sub de0}=-0.9278{+-}0.0626, q{sub 0}=-0.5951{+-}0.0586 (flat case) and w{sub de0}=-0.9501{+-}0.1442, q{sub 0}=-0.6164{+-}0.0805 (nonflat case). Compared to the {Lambda}CDM model, it is found the current combined data sets do not favor the holographic dark energy model over the {Lambda}CDM model.« less
  • We constrain an interacting, holographic dark energy model, first proposed by two of us in [1], with observational data from supernovae, CMB shift, baryon acoustic oscillations, x-rays, and the Hubble rate. The growth function for this model is also studied. The model fits the data reasonably well but still the conventional ΛCDM model fares better. Nevertheless, the holographic model greatly alleviates the coincidence problem and shows compatibility at 1σ confidence level with the age of the old quasar APM 08279+5255.