110,057 research outputs found
Simplicial minisuperspace models in the presence of a massive scalar field with arbitrary scalar coupling
We extend previous simplicial minisuperspace models to account for arbitrary
scalar coupling \eta R\phi^2.Comment: 24 pages and 9 figures. Accepted for publication by Classical and
Quantum Gravit
Anisotropic simplicial minisuperspace model
The computation of the simplicial minisuperspace wavefunction in the case of
anisotropic universes with a scalar matter field predicts the existence of a
large classical Lorentzian universe like our own at late timesComment: 19 pages, Latex, 6 figure
A Highly Predictive Ansatz for Leptonic Mixing and CP Violation
We suggest a simple highly predictive ansatz for charged lepton and light
neutrino mass matrices, based on the assumption of universality of Yukawa
couplings. Using as input the charged lepton masses and light neutrino masses,
the six parameters characterizing the leptonic mixing matrix , are
predicted in terms of a single phase , which takes a value around
. Correlations among variuos physical quantities are
obtained, in particular is predicted as a function of
, and , and
restricted to the range .Comment: 9 pages, 4 figure
Stochastic group selection model for the evolution of altruism
We study numerically and analytically a stochastic group selection model in
which a population of asexually reproducing individuals, each of which can be
either altruist or non-altruist, is subdivided into reproductively isolated
groups (demes) of size . The cost associated with being altruistic is
modelled by assigning the fitness , with , to the
altruists and the fitness 1 to the non-altruists. In the case that the
altruistic disadvantage is not too large, we show that the finite
fluctuations are small and practically do not alter the deterministic results
obtained for . However, for large these fluctuations
greatly increase the instability of the altruistic demes to mutations. These
results may be relevant to the dynamics of parasite-host systems and, in
particular, to explain the importance of mutation in the evolution of parasite
virulence.Comment: 12 pages, 7 figure
Euclidean analysis of the entropy functional formalism
The attractor mechanism implies that the supersymmetric black hole near
horizon solution is defined only in terms of the conserved charges and is
therefore independent of asymptotic moduli. Starting only with the near horizon
geometry, Sen's entropy functional formalism computes the entropy of an extreme
black hole by means of a Legendre transformation where the electric fields are
defined as conjugated variables to the electric charges. However, traditional
Euclidean methods require the knowledge of the full geometry to compute the
black hole thermodynamic quantities. We establish the connection between the
entropy functional formalism and the standard Euclidean formalism taken at zero
temperature. We find that Sen's entropy function 'f' (on-shell) matches the
zero temperature limit of the Euclidean action. Moreover, Sen's near horizon
angular and electric fields agree with the chemical potentials that are defined
from the zero-temperature limit of the Euclidean formalism.Comment: 37 pages. v3: Footnote and Reference added. Published versio
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