Multiverse Understanding of Cosmological Coincidences

@article{Bousso2009MultiverseUO,
  title={Multiverse Understanding of Cosmological Coincidences},
  author={Raphael Bousso and Lawrence J. Hall and Yasunori Nomura},
  journal={Physical Review D},
  year={2009},
  volume={80},
  pages={063510}
}
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 vacuum domination do not differ by many orders of magnitude, but are all comparable to the present age of the universe. By scanning four landscape parameters simultaneously, we show that this quadruple coincidence is resolved. We assume only that the statistical distribution of parameter values in… 

Figures from this paper

The Cosmological Constant in the Quantum Multiverse
Recently, a new framework for describing the multiverse has been proposed which is based on the principles of quantum mechanics. The framework allows for well-defined predictions, both regarding
Predictions from Star Formation in the Multiverse
We compute trivariate probability distributions in the landscape, scanning simultaneously over the cosmological constant, the primordial density contrast, and spatial curvature. We consider two
The degree of fine-tuning in our universe — and others
Geometric origin of coincidences and hierarchies in the landscape
We show that the geometry of cutoffs on eternal inflation strongly constrains predictions for the time scales of vacuum domination, curvature domination, and observation. We consider three measure
Varying Constants, Gravitation and Cosmology
  • J. Uzan
  • Physics
    Living reviews in relativity
  • 2011
TLDR
The relations between the constants, the tests of the local position invariance and of the universality of free fall are detailed, and the unification mechanisms and the relation between the variation of different constants are described.
The weak scale from BBN
A bstractThe measured values of the weak scale, v, and the first generation masses, mu,d,e, are simultaneously explained in the multiverse, with all these parameters scanning independently. At the
Ab initio estimates of the size of the observable universe
When one combines multiverse predictions by Bousso, Hall, and Nomura for the observed age and size of the universe in terms of the proton and electron charge and masses with anthropic predictions of
Elucidation of 'Cosmic Coincidence'
. In the standard cosmological model the dark energy (DE) and nonrelativistic (NR) matter densities are determined to be comparable at the present time, in spite of their greatly different evolution
The Entropic Landscape
We initiate a quantitative exploration of the entire landscape. Predictions thus far have focused on subsets of landscape vacua that share most properties with our own. Using the entropic principle
Inflation after false vacuum decay: Observational prospects after Planck
We assess two potential signals of the formation of our universe by the decay of a false vacuum. Negative spatial curvature is one possibility, but the window for its detection is now small. However,
...
...

References

SHOWING 1-10 OF 52 REFERENCES
Cosmological constant and the time of its dominance
We explore a model in which the cosmological constant L and the density contrast at the time of recombination s rec are random variables, whose range and a priori probabilities are determined by the
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
Likely Values of the Cosmological Constant
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
Predicting the cosmological constant from the causal entropic principle
We compute the expected value of the cosmological constant in our universe from the causal entropic principle. Since observers must obey the laws of thermodynamics and causality, the principle
Dimensionless constants, cosmology and other dark matters
We identify 31 dimensionless physical constants required by particle physics and cosmology, and emphasize that both microphysical constraints and selection effects might help elucidate their origin.
Why Is the Cosmic Microwave Background Fluctuation Level 10?5?
We explore the qualitative changes that would occur if the amplitude Q ~ 10-5 of cosmological density fluctuations were different. If Q 10-6, the cosmological objects that form would have such low
Boltzmann babies in the proper time measure
After commenting briefly on the role of the typicality assumption in science, we advocate a phenomenological approach to the cosmological measure problem. Like any other theory, a measure should be
Quantization of four-form fluxes and dynamical neutralization of the cosmological constant
A four-form gauge flux makes a variable contribution to the cosmological constant. This has often been assumed to take continuous values, but we argue that it has a generalized Dirac quantization
Properties of the scale factor measure
We show that in expanding regions, the scale factor measure can be reformulated as a local measure: Observations are weighted by integrating their physical density along a geodesic that starts in the
Evidence for the Multiverse in the Standard Model and Beyond
In any theory it is unnatural if the observed values of parameters lie very close to special values that determine the existence of complex structures necessary for observers. A naturalness
...
...