Likely Values of the Cosmological Constant

@article{Martel1997LikelyVO,
  title={Likely Values of the Cosmological Constant},
  author={Hugo Martel and Paul R. Shapiro and Steven Weinberg},
  journal={The Astrophysical Journal},
  year={1997},
  volume={492},
  pages={29 - 40}
}
In theories in which the cosmological constant takes a variety of values in different "subuniverses," the probability distribution of its observed values is conditioned by the requirement that there be someone to measure it. This probability is proportional to the fraction of matter that is destined to condense out of the background into mass concentrations large enough to form observers. We calculate this "collapsed fraction" with a simple, pressure-free, spherically symmetric, nonlinear model… 

Predicting the cosmological constant with the scale-factor cutoff measure

It is well known that anthropic selection from a landscape with a flat prior distribution of cosmological constant {lambda} gives a reasonable fit to observation. However, a realistic model of the

The cosmological constant problem and quintessence

I briefly review the cosmological constant problem and the issue of dark energy (or quintessence). Within the framework of quantum field theory, the vacuum expectation value of the energy momentum

What does inflation really predict?

If the inflaton potential has multiple minima, as may be expected in, e.g., the string theory ‘landscape’, inflation predicts a probability distribution for the cosmological parameters describing

Density perturbations and the cosmological constant from inflationary landscapes

An anthropic understanding of the cosmological constant requires that the vacuum energy at late time scans from one patch of the universe to another. If the vacuum energy during inflation also scans,

The cosmological constant

The energy density of the vacuum, Λ, is at least 60 orders of magnitude smaller than several known contributions to it. Approaches to this problem are tightly constrained by data ranging from

Spatial Gradients in the Cosmological Constant Typeset Using Revt E X

It is possible that there may be differences in the fundamental physical parameters from one side of the observed universe to the other. I show that the cosmological constant is likely to be the most

Spatial gradients in the cosmological constant

It is possible that there may be differences in the fundamental physical parameters from one side of the observed universe to the other. I show that the cosmological constant is likely to be the most

Multiverse Understanding of Cosmological Coincidences

There is a deep cosmological mystery: although dependent on very different underlying physics, the time scales of structure formation, of galaxy cooling (both radiatively and against the CMB), and of

The influence of cosmological constant in temperature oscillations of a gas moving close to circular geodesic

The aim of this work is to analyze and to verify the effects of the charge and cosmological constant on the temperature oscillations that occur in a gas in a circular motion close to geodesic under

Living With Lambda

The cosmological constant is an energy associated with the vacuum, that is, with 'empty space'. The possibility of a nonzero cosmological constant Λ has been entertained several times in the past for
...

References

SHOWING 1-10 OF 27 REFERENCES

The observational case for a low-density Universe with a non-zero cosmological constant

OBSERVATIONS are providing progressively tighter constraints on cosmological models advanced to explain the formation of large-scale structure in the Universe. These include recent determinations of

Cold dark matter models with a cosmological constant

We use linear and quasi-linear perturbation theory to analyse cold dark matter models of structure formation in spatially flat models with a cosmological constant. Both a tilted spectrum of density

The cluster abundance in flat and open cosmologies

We use the galaxy cluster X-ray temperature distribution function to constrain the am­ plitude of the power spectrum of density inhomogeneities on the scale corresponding to clusters. We carry out

Predictions from quantum cosmology.

  • Vilenkin
  • Physics
    Physical review letters
  • 1995
TLDR
The picture that has emerged from this line of development is that a small closed universe can spontaneously nucleate out of nothing, where by ‘nothing’ I mean a state with no classical space and time.

The statistics of peaks of Gaussian random fields

A set of new mathematical results on the theory of Gaussian random fields is presented, and the application of such calculations in cosmology to treat questions of structure formation from

Reionization in a cold dark matter universe: The feedback of galaxy formation on the intergalactic medium

We study the coupled evolution of the intergalactic medium (IGM) and the emerging structure in the universe in the context of the cold dark matter (CDM) model, with a special focus on the

Making predictions in an eternally inflating universe.

  • Vilenkin
  • Physics
    Physical review. D, Particles and fields
  • 1995
TLDR
A method of comparing the volumes which is rather insensitive to the choice of t is proposed, which is then applied to evaluate the relative probability of different minima of the inflaton potential and the probability distribution for the density fluctuation spectra.

The cosmological constant is back

A diverse set of observations now compellingly suggest that the universe possesses a nonzero cosmological constant. In the context of quantum-field theory a cosmological constant corresponds to the

Big-bang nucleosynthesis and the baryon density of the universe

TLDR
The agreement between the predicted and observed abundances of deuterium, helium-3, helium -4, and lithium-7 confirms the standard cosmology model and allows accurate determination of the baryon density, which is pivotal to the establishment of two dark-matter problems.

Eternally Existing Self-Reproducing Inflationary Universe

It is shown that the large-scale quantum fluctuations of the scalar field generated in the chaotic inflation scenario lead to an infinite process of self-reproduction of inflationary mini-universes.