The cosmological constant and the paradigm of adiabaticity

@article{Trotta2003TheCC,
  title={The cosmological constant and the paradigm of adiabaticity},
  author={Roberto Trotta},
  journal={New Astronomy Reviews},
  year={2003},
  volume={47},
  pages={769-774}
}
  • R. Trotta
  • Published 29 April 2003
  • Physics
  • New Astronomy Reviews
Abstract We discuss the value of the cosmological constant as recovered from cosmic microwave background (CMB) and large scale structure (LSS) data and the robustness of the results when general isocurvature initial conditions are allowed for, as opposed to purely adiabatic perturbations. The Bayesian and frequentist statistical approaches are compared. It is shown that pre-WMAP CMB and LSS data tend to be incompatible with a non-zero cosmological constant, regardless of the type of initial… 

Figures from this paper

The Nature of Primordial Perturbations in the Light of CMB Observations
The universe is filled with nearly isotropic cosmic microwave background (CMB) radiation, which has a blackbody spectrum of temperature T ≈ 2.73K. In addition, there are tiny direction dependent
Uncorrelated estimates of the primordial power spectrum
We use the localized principle component analysis to detect deviations front scale invariance of the primordial power spectrum of curvature perturbations. With the technique we make uncorrelated
Isocurvature modes and Baryon Acoustic Oscillations
The measurement of Baryonic Acoustic Oscillations from galaxy surveys is well known to be a robust and powerful tool to constrain dark energy. This method relies on the knowledge of the size of the
Isocurvature modes and Baryon Acoustic Oscillations II: gains from combining CMB and Large Scale Structure
We consider cosmological parameters estimation in the presence of a non-zero isocurvature contribution in the primordial perturbations. A previous analysis showed that even a tiny amount of
CONSTRAINTS ON SCALAR AND TENSOR PERTURBATIONS IN PHENOMENOLOGICAL AND TWO-FIELD INFLATION MODELS: BAYESIAN EVIDENCES FOR PRIMORDIAL ISOCURVATURE AND TENSOR MODES
We constrain cosmological models where the primordial perturbations have an adiabatic and a (possibly correlated) cold dark matter (CDM) or baryon isocurvature component. We use both a
Weighing the universe with photometric redshift surveys and the impact on dark energy forecasts
With a wariness of Occam's razor awakened by the discovery of cosmic acceleration, we abandon the usual assumption of zero mean curvature and ask how well it can be determined by planned surveys. We

References

SHOWING 1-10 OF 26 REFERENCES
Cosmological constant and general isocurvature initial conditions
We investigate in detail the question whether a non-vanishing cosmological constant is required by present-day cosmic microwave background and large scale structure data when general isocurvature
Cosmic microwave background anisotropies with mixed isocurvature perturbations.
TLDR
It is shown that, for more generic initial conditions, not only the best fit values are very different but the allowed parameter range enlarges dramatically, which raises the question which cosmological information can be reliably extracted from these data.
Constraining isocurvature perturbations with cosmic microwave background polarization.
TLDR
The role of cosmic microwave background polarization data in constraining the presence of primordial isocurvature modes is examined and a comparably sensitive polarization measurement on the same angular scales will permit a determination of the curvature without the prior assumption of adiabaticity.
Characterizing the primordial cosmic perturbations using map and Planck
The most general homogeneous and isotropic statistical ensemble of linear scalar perturbations regular at early times in a universe with only photons, baryons, neutrinos, and a cold dark matter (CDM)
A measurement by BOOMERANG of multiple peaks in the angular power spectrum of the cosmic microwave background
This paper presents a measurement of the angular power spectrum of the cosmic microwave background from l = 75 to l = 1025 (~10' to 24) from a combined analysis of four 150 GHz channels in the
General primordial cosmic perturbation
We consider the most general primordial cosmological perturbation in a universe filled with photons, baryons, neutrinos, and a hypothetical cold dark matter (CDM) component within the framework of
Structure in the COBE differential microwave radiometer first year maps
Results of the first year of data from the differential microwave radiometers on the Cosmic Background Explorer are presented. Statistically significant structure that is well described as
Final Results from the Hubble Space Telescope Key Project to Measure the Hubble Constant
We present here the final results of the Hubble Space Telescope (HST) Key Project to measure the Hubble constant. We summarize our method, the results, and the uncertainties, tabulate our revised
Cosmic temperature fluctuations from two years of COBE differential microwave radiometers observations
The first two years of COBE DMR observations of the CMB anisotropy are analyzed and compared with our previously published first year results. The results are consistent, but the addition of the
The power spectrum of galaxies in the 2dF 100k redshift survey
We compute the real-space power spectrum and the redshift-space distortions of galaxies in the 2dF 100k galaxy redshift survey using pseudo-Karhunen-Loeve eigenmodes and the stochastic bias
...
1
2
3
...