242,301 research outputs found
Emergence of inflationary perturbations in the CSL model
The inflationary paradigm is the most successful model that explains the
observed spectrum of primordial perturbations. However, the precise emergence
of such inhomogeneities and the quantum-to-classical transition of the
perturbations has not yet reached a consensus among the community. The
Continuous Spontaneous Localization model (CSL), in the cosmological context,
might be used to provide a solution to the mentioned issues by considering a
dynamical reduction of the wave function. The CSL model has been applied to the
inflationary universe before and different conclusions have been obtained. In
this letter, we use a different approach to implement the CSL model during
inflation. In particular, in addition to accounting for the
quantum-to-classical transition, we use the CSL model to generate the
primordial perturbations, that is, the dynamical evolution provided by the CSL
model is responsible for the transition from a homogeneous and isotropic
initial state to a final one lacking such symmetries. Our approach leads to
results that can be clearly distinguished from preceding works. Specifically,
the scalar and tensor power spectra are not time-dependent, and retains the
amplification mechanism of the CSL model. Moreover, our framework depends only
on one parameter (the CSL parameter) and its value is consistent with
cosmological and laboratory observations.Comment: 14 pages. Final version. To be published in EPJ
A Perl Package and an Alignment Tool for Phylogenetic Networks
Phylogenetic networks are a generalization of phylogenetic trees that allow
for the representation of evolutionary events acting at the population level,
like recombination between genes, hybridization between lineages, and lateral
gene transfer. While most phylogenetics tools implement a wide range of
algorithms on phylogenetic trees, there exist only a few applications to work
with phylogenetic networks, and there are no open-source libraries either.
In order to improve this situation, we have developed a Perl package that
relies on the BioPerl bundle and implements many algorithms on phylogenetic
networks. We have also developed a Java applet that makes use of the
aforementioned Perl package and allows the user to make simple experiments with
phylogenetic networks without having to develop a program or Perl script by
herself.
The Perl package has been accepted as part of the BioPerl bundle. It can be
downloaded from http://dmi.uib.es/~gcardona/BioInfo/Bio-PhyloNetwork.tgz. The
web-based application is available at http://dmi.uib.es/~gcardona/BioInfo/. The
Perl package includes full documentation of all its features.Comment: 5 page
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