Lowest Order Constrained Variational Calculation of the Polarized Nuclear Matter with the Modern AV18AV_{18} Potential

The lowest order constrained variational method is applied to calculate the polarized symmetrical nuclear matter properties with the modern $AV_{18}$ potential performing microscopic calculations. Results based on the consideration of magnetic properties show no sign of phase transition to a ferromagnetic phase.Comment: 19 pages, 6 figure

Polarized Neutron Matter: A Lowest Order Constrained Variational Approach

In this paper, we calculate some of the polarized neutron matter properties, using the lowest order constrained variational method with the $AV_{18}$ potential and employing a microscopic point of view. A comparison is also made between our results and those of other many-body techniques.Comment: 23 pages, 8 figure

Anomalies in electrostatic calibrations for the measurement of the Casimir force in a sphere-plane geometry

We have performed precision electrostatic calibrations in the sphere-plane geometry and observed anomalous behavior. Namely, the scaling exponent of the electrostatic signal with distance was found to be smaller than expected on the basis of the pure Coulombian contribution and the residual potential found to be distance dependent. We argue that these findings affect the accuracy of the electrostatic calibrations and invite reanalysis of previous determinations of the Casimir force.Comment: 4 pages, 4 figure

Spin polarized neutron matter within the Dirac-Brueckner-Hartree-Fock approach

The relation between energy and density (known as the nuclear equation of state) plays a major role in a variety of nuclear and astrophysical systems. Spin and isospin asymmetries can have a dramatic impact on the equation of state and possibly alter its stability conditions. An example is the possible manifestation of ferromagnetic instabilities, which would indicate the existence, at a certain density, of a spin-polarized state with lower energy than the unpolarized one. This issue is being discussed extensively in the literature and the conclusions are presently very model dependent. We will report and discuss our recent progress in the study of spin-polarized neutron matter. The approach we take is microscopic and relativistic. The calculated neutron matter properties are derived from realistic nucleon-nucleon interactions. This makes it possible to understand the nature of the EOS properties in terms of specific features of the nuclear force model.Comment: 6 pages, 11 figures, revised/extended calculation

A zeta function approach to the relation between the numbers of symmetry planes and axes of a polytope

A derivation of the Ces\`aro-Fedorov relation from the Selberg trace formula on an orbifolded 2-sphere is elaborated and extended to higher dimensions using the known heat-kernel coefficients for manifolds with piecewise-linear boundaries. Several results are obtained that relate the coefficients, $b_i$, in the Shephard-Todd polynomial to the geometry of the fundamental domain. For the 3-sphere we show that $b_4$ is given by the ratio of the volume of the fundamental tetrahedron to its Schl\"afli reciprocal.Comment: Plain TeX, 26 pages (eqn. (86) corrected

The flying radiation case

The Los Alamos foil implosion program has the goal of producing an intense, high-energy density x-ray source by converting the energy of a magnetically imploded plasma into radiation and material energy. One of the methods for converting the plasma energy into thermal energy and radiation and utilizing it for experiments is called the flying radiation case (FRC). In this paper the authors shall model the FRC and provide a physical description of the processes involved. An analytic model of a planar FRC in the hydrodynamic approximation is used to describe the assembly and shock heating of a central cushion by a conducting liner driver. The results are also used to benchmark a hydrodynamics code for modeling an FRC. They then use a radiation-hydrodynamics computational model to explore the effects of radiation production and transport when a gold plasma assembles on a CH cushion. Results are presented for the structure and evolution of the radiation hohlraum

Universal behavior of quantum Green's functions

We consider a general one-particle Hamiltonian H = - \Delta_r + u(r) defined in a d-dimensional domain. The object of interest is the time-independent Green function G_z(r,r') = . Recently, in one dimension (1D), the Green's function problem was solved explicitly in inverse form, with diagonal elements of Green's function as prescribed variables. The first aim of this paper is to extract from the 1D inverse solution such information about Green's function which cannot be deduced directly from its definition. Among others, this information involves universal, i.e. u(r)-independent, behavior of Green's function close to the domain boundary. The second aim is to extend the inverse formalism to higher dimensions, especially to 3D, and to derive the universal form of Green's function for various shapes of the confining domain boundary.Comment: 46 pages, the shortened version submitted to J. Math. Phy

Thermal and dissipative effects in Casimir physics

We report on current efforts to detect the thermal and dissipative contributions to the Casimir force. For the thermal component, two experiments are in progress at Dartmouth and at the Institute Laue Langevin in Grenoble. The first experiment will seek to detect the Casimir force at the largest explorable distance using a cylinder-plane geometry which offers various advantages with respect to both sphere-plane and parallel-plane geometries. In the second experiment, the Casimir force in the parallel-plane configuration is measured with a dedicated torsional balance, up to 10 micrometers. Parallelism of large surfaces, critical in this configuration, is maintained through the use of inclinometer technology already implemented at Grenoble for the study of gravitationally bound states of ultracold neutrons, For the dissipative component of the Casimir force, we discuss detection techniques based upon the use of hyperfine spectroscopy of ultracold atoms and Rydberg atoms. Although quite challenging, this triad of experimental efforts, if successful, will give us a better knowledge of the interplay between quantum and thermal fluctuations of the electromagnetic field and of the nature of dissipation induced by the motion of objects in a quantum vacuum.Comment: Contribution to QFEXT'06, appeared in special issue of Journal of Physics

The Active Traveling Wave in the Cochlea

A sound stimulus entering the inner ear excites a deformation of the basilar membrane which travels along the cochlea towards the apex. It is well established that this wave-like disturbance is amplified by an active system. Recently, it has been proposed that the active system consists of a set of self-tuned critical oscillators which automatically operate at an oscillatory instability. Here, we show how the concepts of a traveling wave and of self-tuned critical oscillators can be combined to describe the nonlinear wave in the cochlea.Comment: 5 pages, 2 figure