Nonthermal THz to TeV Emission from Stellar Wind Shocks in the Galactic Center

The central parsec of the Galaxy contains dozens of massive stars with a cumulative mass loss rate of ~ 10^{-3} solar masses per year. Shocks among these stellar winds produce the hot plasma that pervades the central part of the galaxy. We argue that these stellar wind shocks also efficiently accelerate electrons and protons to relativistic energies. The relativistic electrons inverse Compton scatter the ambient ultraviolet and far infrared radiation field, producing high energy gamma-rays with a roughly constant luminosity from \~ GeV to ~ 10 TeV. This can account for the TeV source seen by HESS in the Galactic Center. Our model predicts a GLAST counterpart to the HESS source with a luminosity of ~ 10^{35} ergs/s and cooling break at ~ 4 GeV. Synchrotron radiation from the same relativistic electrons should produce detectable emission at lower energies, with a surface brightness ~ 10^{32} B^2_{-3} ergs/s/arcsec^2 from ~ THz to ~ keV, where B_{-3} is the magnetic field strength in units of mG. The observed level of diffuse thermal X-ray emission in the central parsec requires B < 300 micro-G in our models. Future detection of the diffuse synchrotron background in the central parsec can directly constrain the magnetic field strength, providing an important boundary condition for models of accretion onto Sgr A*.Comment: submitted to ApJ Letter

Analog simulation of the Voigt solid

A method of reducing a mixed partial differential equation with boundary conditions to a form suitable for programming on the analog computer is developed. Presented along with the computer program set up to be used on the EAI TR-48 analog computer is a systematic check procedure to indicate possible computer malfunctions and programming errors. The results of the computer simulation are presented and supported with observed data --Abstract, page ii

Mauriac Syndrome in a Child with a Positive Antinuclear Antibody Screen

A 17-year-old male with type 1 diabetes mellitus (T1DM) presented to clinic with elevated transaminases and a positive antinuclear antibody (ANA) screen. Due to concern for autoimmune hepatitis, a liver biopsy was performed which revealed Mauriac syndrome. This case report is the second known description of a child with Mauriac syndrome presenting with positive autoimmune markers

Thin-disk laser pump schemes for large number of passes and moderate pump source quality

Novel thin-disk laser pump layouts are proposed yielding an increased number of passes for a given pump module size and pump source quality. These novel layouts result from a general scheme which bases on merging two simpler pump optics arrangements. Some peculiar examples can be realized by adapting standard commercially available pump optics simply by intro ducing an additional mirror-pair. More pump passes yield better efficiency, opening the way for usage of active materials with low absorption. In a standard multi-pass pump design, scaling of the number of beam passes brings ab out an increase of the overall size of the optical arrangement or an increase of the pump source quality requirements. Such increases are minimized in our scheme, making them eligible for industrial applicationsComment: 16 pages, 9 figure

Many-body theory of excitation dynamics in an ultracold Rydberg gas

We develop a theoretical approach for the dynamics of Rydberg excitations in ultracold gases, with a realistically large number of atoms. We rely on the reduction of the single-atom Bloch equations to rate equations, which is possible under various experimentally relevant conditions. Here, we explicitly refer to a two-step excitation-scheme. We discuss the conditions under which our approach is valid by comparing the results with the solution of the exact quantum master equation for two interacting atoms. Concerning the emergence of an excitation blockade in a Rydberg gas, our results are in qualitative agreement with experiment. Possible sources of quantitative discrepancy are carefully examined. Based on the two-step excitation scheme, we predict the occurrence of an antiblockade effect and propose possible ways to detect this excitation enhancement experimentally in an optical lattice as well as in the gas phase.Comment: 12 pages, 8 figure

Correlations of Rydberg excitations in an ultra-cold gas after an echo sequence

We show that Rydberg states in an ultra-cold gas can be excited with strongly preferred nearest-neighbor distance if densities are well below saturation. The scheme makes use of an echo sequence in which the first half of a laser pulse excites Rydberg states while the second half returns atoms to the ground state, as in the experiment of Raitzsch et al. [Phys. Rev. Lett. 100 (2008) 013002]. Near to the end of the echo sequence, almost any remaining Rydberg atom is separated from its next-neighbor Rydberg atom by a distance slightly larger than the instantaneous blockade radius half-way through the pulse. These correlations lead to large deviations of the atom counting statistics from a Poissonian distribution. Our results are based on the exact quantum evolution of samples with small numbers of atoms. We finally demonstrate the utility of the omega-expansion for the approximate description of correlation dynamics through an echo sequence.Comment: 8 pages, 6 figure

On knotted streamtubes in incompressible hydrodynamical flow and a restricted conserved quantity

For certain families of fluid flow, a new conserved quantity -- stream-helicity -- has been established.Using examples of linked and knotted streamtubes, it has been shown that stream-helicity does, in certain cases, entertain itself with a very precise topological meaning viz, measure of the degree of knottedness or linkage of streamtubes.As a consequence, stream-helicity emerges as a robust topological invariant.Comment: This extended version is the basically a more clarified version of the previous submission physics/0611166v

Demonstrating the feasibility of standardized application program interfaces that will allow mobile/portable terminals to receive services combining UMTS and DVB-T

Crucial to the commercial exploitation of any service combining UMTS and DVB-T is the availability of standardized API’s adapted to the hybrid UMTS and DVB-T network and to the technical limitations of mobile/portable terminals. This paper describes work carried out in the European Commission Framework Program 5 (FP5) project CONFLUENT to demonstrate the feasibility of such Application Program Interfaces (API’s) by enabling the reception of a Multimedia Home Platform (MHP) based application transmitted over DVB-T on five different terminals with parts of the service running on a mobile phone

On the formation and decay of a molecular ultracold plasma

Double-resonant photoexcitation of nitric oxide in a molecular beam creates a dense ensemble of $50f(2)$ Rydberg states, which evolves to form a plasma of free electrons trapped in the potential well of an NO$^+$ spacecharge. The plasma travels at the velocity of the molecular beam, and, on passing through a grounded grid, yields an electron time-of-flight signal that gauges the plasma size and quantity of trapped electrons. This plasma expands at a rate that fits with an electron temperature as low as 5 K, colder that typically observed for atomic ultracold plasmas. The recombination of molecular NO$^+$ cations with electrons forms neutral molecules excited by more than twice the energy of the NO chemical bond, and the question arises whether neutral fragmentation plays a role in shaping the redistribution of energy and particle density that directs the short-time evolution from Rydberg gas to plasma. To explore this question, we adapt a coupled rate-equations model established for atomic ultracold plasmas to describe the energy-grained avalanche of electron-Rydberg and electron-ion collisions in our system. Adding channels of Rydberg predissociation and two-body, electron- cation dissociative recombination to the atomic formalism, we investigate the kinetics by which this relaxation distributes particle density and energy over Rydberg states, free electrons and neutral fragments. The results of this investigation suggest some mechanisms by which molecular fragmentation channels can affect the state of the plasma