6,214 research outputs found
On formation of long-living states
The motion of a particle in the potential well is studied when the particle
is attached to the infinite elastic string. This is generic with the problem of
dissipative quantum mechanics investigated by Caldeira and Leggett. Besides the
dissipative motion there is another scenario of interaction of the string with
the particle attached. Stationary particle-string states exist with string
deformations accompanying the particle. This is like polaronic states in
solids. Our polaronic states in the well are non-decaying and with continuous
energy spectrum. Perhaps these states have a link to quantum electrodynamics.
Quantum mechanical wave function, singular on some line, is smeared out by
electron "vibrations" due to the interaction with photons. In those anomalous
states the smeared singularity position would be analogous to the place where
the particle is attached to the string
The model of neutrino vacuum flavour oscillations and quantum mechanics
It is shown that the model of vacuum flavour oscillations is in disagreement
with quantum mechanics theorems and postulates. Features of the model are
analyzed. It is noted that apart from the number of mixed mass states neutrino
oscillations are forbidden by Fock-Krylov theorem. A possible reason of
oscillation model inadequacy is discussed.Comment: 12 page
How to infer relative fitness from a sample of genomic sequences
Mounting evidence suggests that natural populations can harbor extensive
fitness diversity with numerous genomic loci under selection. It is also known
that genealogical trees for populations under selection are quantifiably
different from those expected under neutral evolution and described
statistically by Kingman's coalescent. While differences in the statistical
structure of genealogies have long been used as a test for the presence of
selection, the full extent of the information that they contain has not been
exploited. Here we shall demonstrate that the shape of the reconstructed
genealogical tree for a moderately large number of random genomic samples taken
from a fitness diverse, but otherwise unstructured asexual population can be
used to predict the relative fitness of individuals within the sample. To
achieve this we define a heuristic algorithm, which we test in silico using
simulations of a Wright-Fisher model for a realistic range of mutation rates
and selection strength. Our inferred fitness ranking is based on a linear
discriminator which identifies rapidly coalescing lineages in the reconstructed
tree. Inferred fitness ranking correlates strongly with actual fitness, with a
genome in the top 10% ranked being in the top 20% fittest with false discovery
rate of 0.1-0.3 depending on the mutation/selection parameters. The ranking
also enables to predict the genotypes that future populations inherit from the
present one. While the inference accuracy increases monotonically with sample
size, samples of 200 nearly saturate the performance. We propose that our
approach can be used for inferring relative fitness of genomes obtained in
single-cell sequencing of tumors and in monitoring viral outbreaks
On the modulus of continuity for spectral measures in substitution dynamics
The paper gives first quantitative estimates on the modulus of continuity of
the spectral measure for weak mixing suspension flows over substitution
automorphisms, which yield information about the "fractal" structure of these
measures. The main results are, first, a Hoelder estimate for the spectral
measure of almost all suspension flows with a piecewise constant roof function;
second, a log-Hoelder estimate for self-similar suspension flows; and, third, a
Hoelder asymptotic expansion of the spectral measure at zero for such flows.
Our second result implies log-Hoelder estimates for the spectral measures of
translation flows along stable foliations of pseudo-Anosov automorphisms. A key
technical tool in the proof of the second result is an "arithmetic-Diophantine"
proposition, which has other applications. In the appendix this proposition is
used to derive new decay estimates for the Fourier transforms of Bernoulli
convolutions.Comment: 42 pages, accepted version; to appear in Advances in Mathematic
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