Numerical Models of Spin-Orbital Coupling in Neutron Star Binaries

We present a new numerical scheme for solving the initial value problem for quasiequilibrium binary neutron stars allowing for arbitrary spins. We construct sequences of circular-orbit binaries of varying separation, keeping the rest mass and circulation constant along each sequence. The spin angular frequency of the stars is shown to vary along the sequence, a result that can be derived analytically in the PPN limit. This spin effect, in addition to leaving an imprint on the gravitational waveform emitted during binary inspiral, is measurable in the electromagnetic signal if one of the stars is a pulsar visible from Earth.Comment: 4 pages, 3 figures. Submitted to the Proceedings of the "X Marcel Grossmann Meeting on General Relativity" in Rio de Janeiro, Brazil, July 20-26 (2003

Critical Temperature for α\alpha-Particle Condensation within a Momentum Projected Mean Field Approach

Alpha-particle (quartet) condensation in homogeneous spin-isospin symmetric nuclear matter is investigated. The usual Thouless criterion for the critical temperature is extended to the quartet case. The in-medium four-body problem is strongly simplified by the use of a momentum projected mean field ansatz for the quartet. The self-consistent single particle wave functions are shown and discussed for various values of the density at the critical temperature

Overlapping resonances in the control of intramolecular vibrational redistribution

Coherent control of bound state processes via the interfering overlapping resonances scenario [Christopher et al., J. Chem. Phys. 123, 064313 (2006)] is developed to control intramolecular vibrational redistribution (IVR). The approach is applied to the flow of population between bonds in a model of chaotic OCS vibrational dynamics, showing the ability to significantly alter the extent and rate of IVR by varying quantum interference contributions.Comment: 10 pages, 7 figure

Two-dimensional shapes and lemniscates

A shape in the plane is an equivalence class of sufficiently smooth Jordan curves, where two curves are equivalent if one can be obtained from the other by a translation and a scaling. The fingerprint of a shape is an equivalence of orientation preserving diffeomorphisms of the unit circle, where two diffeomorphisms are equivalent if they differ by right composition with an automorphism of the unit disk. The fingerprint is obtained by composing Riemann maps onto the interior and exterior of a representative of a shape in a suitable way. In this paper, we show that there is a one-to-one correspondence between shapes defined by polynomial lemniscates of degree n and nth roots of Blaschke products of degree n. The facts that lemniscates approximate all Jordan curves in the Hausdorff metric and roots of Blaschke products approximate all orientation preserving diffeomorphisms of the circle in the C^1-norm suggest that lemniscates and roots of Blaschke products are natural objects to study in the theory of shapes and their fingerprints

Some relations for one-part double Hurwitz numbers

In this very short note we slightly generalize some relations for one-part double Hurwitz numbers from math.AG/0209282.Comment: 3 page

Benchmark Calculations for Perchlorate from Three Human Cohorts

The presence of low concentrations of perchlorate in some drinking water sources has led to concern regarding potential effects on the thyroid. In a recently published report, the National Academy of Sciences indicated that the perchlorate dose required to cause hypothyroidism in adults would probably be > 0.40 mg/kg-day for months or longer. In this study, we calculated benchmark doses for perchlorate from thyroid-stimulating hormone (TSH) and free thyroxine (T(4)) serum indicators from two occupational cohorts with long-term exposure to perchlorate, and from a clinical study of volunteers exposed to perchlorate for 2 weeks. The benchmark dose for a particular serum indicator was defined as the dose predicted to cause an additional 5 or 10% of persons to have a serum measurement outside of the normal range. Using the data from the clinical study, we estimated the half-life of perchlorate in serum at 7.5 hr and the volume of distribution at 0.34 L/kg. Using these estimates and measurements of perchlorate in serum or urine, doses in the occupational cohorts were estimated and used in benchmark calculations. Because none of the three studies found a significant effect of perchlorate on TSH or free T(4), all of the benchmark dose estimates were indistinguishable from infinity. The lower 95% statistical confidence limits on benchmark doses estimated from a combined analysis of the two occupational studies ranged from 0.21 to 0.56 mg/kg-day for free T(4) index and from 0.36 to 0.92 mg/kg-day for TSH. Corresponding estimates from the short-term clinical study were within these ranges

Estimations of the Distances of Stellar Collapses in the Galaxy by Analyzing the Energy Spectrum of Neutrino Bursts

The neutrino telescopes of the present generation, depending on their specific features, can reconstruct the neutrino spectra from a galactic burst. Since the optical counterpart could be not available, it is desirable to have at hand alternative methods to estimate the distance of the supernova explosion using only the neutrino data. In this work we present preliminary results on the method we are proposing to estimate the distance from a galactic supernova based only on the spectral shape of the neutrino burst and assumptions on the gravitational binding energy released an a typical supernova explosion due to stellar collapses.Comment: Proceedings of the Second International Symposium on Strong Electromagnetic Fields and Neutron Stars (SMFNS 2011) Instituto de Cibern\'etica, Matem\'atica y F\'isica (ICIMAF) Sociedad Cubana de F\'isica (SCF) Varadero, Cuba, 5-7 May 201

Magnetic fields generated by r-modes in accreting millisecond pulsars

In millisecond pulsars the existence of the Coriolis force allows the development of the so-called Rossby oscillations (r-modes) which are know to be unstable to emission of gravitational waves. These instabilities are mainly damped by the viscosity of the star or by the existence of a strong magnetic field. A fraction of the observed millisecond pulsars are known to be inside Low Mass X-ray Binaries (LMXBs), systems in which a neutron star (or a black hole) is accreting from a donor whose mass is smaller than 1 $M_\odot$. Here we show that the r-mode instabilities can generate strong toroidal magnetic fields by inducing differential rotation. In this way we also provide an alternative scenario for the origin of the magnetars.Comment: 6 pages, 3 figures, Proceedings conference "Theoretical Nuclear Physics", Cortona October 200