6 research outputs found
Model independent analysis of dark energy I: Supernova fitting result
The nature of dark energy is a mystery to us. This paper uses the supernova
data to explore the property of dark energy by some model independent methods.
We first Talyor expanded the scale factor to find out the deceleration
parameter . This result just invokes the Robertson-Walker metric. Then
we discuss several different parameterizations used in the literature. We find
that is almost less than -1 at level. We also find
that the transition redshift from deceleration phase to acceleration phase is
.Comment: v4: minor corrections, main results unchanged. 10 figures, use
revtex, 7 pages, v5: refences updated, will appear in Class. Quantum Gra
Radiative Corrections to the Inflaton Potential as an Explanation of Suppressed Large Scale Power in Density Perturbations and the Cosmic Microwave Background
The Wilkinson Microwave Anisotropy Probe microwave background data suggest
that the primordial spectrum of scalar curvature fluctuations is suppressed at
small wavenumbers. We propose a UV/IR mixing effect in small-field inflationary
models that can explain the observable deviation in WMAP data from the
concordance model. Specifically, in inflationary models where the inflaton
couples to an asymptotically free gauge theory, the radiative corrections to
the effective inflaton potential can be anomalously large. This occurs for
small values of the inflaton field which are of the order of the gauge theory
strong coupling scale. Radiative corrections cause the inflaton potential to
blow up at small values of the inflaton field. As a result, these corrections
can violate the slow-roll condition at the initial stage of the inflation and
suppress the production of scalar density perturbations.Comment: 20 pages, 2 figures, v2: refs added, v3: JCAP versio
Can we predict for the Non-SUSY sector of the Landscape ?
We propose a new selection criteria for predicting the most probable
wavefunction of the universe that propagates on the string landscape
background, by studying its dynamics from a quantum cosmology view. Previously
we applied this proposal to the sector of the landscape. In this work
the dynamic selection criterion is applied to the investigation of the
non- sector.In the absence of detailed information about its structure,
it is assumed that this sector has a stochastic distribution of vacua
energies.The calculation of a distribution probability for the cosmological
constants , obtained from the density of states ,
indicates that the most probable wavefunction is peaked around universes with
zero . In contrast to the {\it extended wavefunction} solutions
found for the sector with -vacua and peaked around
, wavefunctions residing on the non-
sector exhibit {\it Anderson localization}.Although minisuperspace is a limited
approach it presently provides a dynamical quantum selection rule for the most
probable vacua solution from the landscape.Comment: 6 pages, 1 figur