2,977 research outputs found
Spaces of polynomials with roots of bounded multiplicity
We describe an alternative approach to some results of Vassiliev on spaces of
polynomials, by using the scanning method which was used by Segal in his
investigation of spaces of rational functions. We explain how these two
approaches are related by the Smale-Hirsch Principle or the h-Principle of
Gromov. We obtain several generalizations, which may be of interest in their
own right.Comment: 29 pages, AMS-Te
Asymptotic expansion of a partition function related to the sinh-model
This paper develops a method to carry out the large- asymptotic analysis
of a class of -dimensional integrals arising in the context of the so-called
quantum separation of variables method. We push further ideas developed in the
context of random matrices of size , but in the present problem, two scales
and naturally occur. In our case, the equilibrium measure
is -dependent and characterised by means of the solution to a
Riemann--Hilbert problem, whose large- behavior is analysed in
detail. Combining these results with techniques of concentration of measures
and an asymptotic analysis of the Schwinger-Dyson equations at the
distributional level, we obtain the large- behavior of the free energy
explicitly up to . The use of distributional Schwinger-Dyson is a novelty
that allows us treating sufficiently differentiable interactions and the mixing
of scales and , thus waiving the analyticity assumptions
often used in random matrix theory.Comment: 158 pages, 4 figures (V2 introduction extended, missprints corrected,
clarifications added to lemma 3.1.9 and corollary 3.1.10
Form factor approach to dynamical correlation functions in critical models
We develop a form factor approach to the study of dynamical correlation
functions of quantum integrable models in the critical regime. As an example,
we consider the quantum non-linear Schr\"odinger model. We derive
long-distance/long-time asymptotic behavior of various two-point functions of
this model. We also compute edge exponents and amplitudes characterizing the
power-law behavior of dynamical response functions on the particle/hole
excitation thresholds. These last results confirm predictions based on the
non-linear Luttinger liquid method. Our results rely on a first principles
derivation, based on the microscopic analysis of the model, without invoking,
at any stage, some correspondence with a continuous field theory. Furthermore,
our approach only makes use of certain general properties of the model, so that
it should be applicable, with possibly minor modifications, to a wide class of
(not necessarily integrable) gapless one dimensional Hamiltonians.Comment: 33 page
Dysplazja kregosłupowo-przynasadowa : Kozlowski
Background: Kozlowski type spondylo-metaphyseal dysplasia is the most frequent form among spondylometaphyseal dysplasias. Case report: The first cases of such dysplasia among Gypsies - a father and two sons - have been described. Conclusions: Radiographic examination is the only means by which to diagnose Kozlowski type spondylometaphyseal dysplasia with certainty. Correct diagnosis is not only prognostic for the course of the disease and its complications, but also excludes the necessity of further, often expensive, investigations
An ice giant exoplanet interpretation of the anomaly in microlensing event OGLE-2011-BLG-0173
We analyze the microlensing event OGLE-2011-BLG-0173, which shows a small
perturbation at the end of the microlensing event caused by the primary lens.
We consider both binary lens and binary source models and we explore their
degeneracies, some of which have not previously been recognized. There are two
families of binary lens solutions, one with a mass ratio
and a separation s~4.6 and the other with q~0.015 and
s~0.22, i.e, both have companions in the planetary regime. We search for
solutions by using Bayesian analysis that includes planet frequency as a prior
and find that the s~4.6 family is the preferred one with ~4 M_Uranus mass
planet on an orbit of ~10 AU. The degeneracies arise from a paucity of
information on the anomaly, demonstrating that high-cadence observations are
essential for characterizing wide-orbit microlensing planets. Hence, we predict
that the planned WFIRST microlensing survey will be less prone to these
degeneracies than the ongoing ground-based surveys. We discuss the known
low-mass, wide-orbit companions and we notice that for the largest projected
separations the mass ratios are either high (consistent with brown dwarf
companions) or low (consistent with Uranus analogs), but intermediate mass
ratios (Jupiter analogs on wide orbits) have not been detected to date, despite
the fact that the sensitivity to such planets should be higher than that of
Uranus analogs. This is therefore tentative evidence of the existence of a
massive ice giant desert at wide separations. On the other hand, given their
low intrinsic detection sensitivity, Uranus analogs may be ubiquitous.Comment: AJ accepted, 6 figures, 4 table
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