Two-peaked and flat-top perfect bright solitons in epsilon-near-zero nonlinear metamaterials: novel Kerr self-trapping mechanisms

We analytically investigate transverse magnetic (TM) spatial bright solitons, as exact solutions of Maxwell's equations, propagating through nonlinear metamaterials whose linear dielectric permittivity is very close to zero and whose effective nonlinear Kerr parameters can be tailored to achieve values not available in standard materials. Exploiting the fact that, in the considered medium, linear and nonlinear polarization can be comparable at feasible and realistic optical intensities, we identify two novel self-trapping mechanisms able to support two-peaked and flat-top solitons, respectively. Specifically, these two novel mechanisms are based on the occurrence of critical points at which the effective nonlinear permittivity vanishes, the two mechanisms differing in the way the compensation between linear and nonlinear polarization is achieved through the non-standard values of the nonlinear parameters.Comment: 7 pages, 4 figure

The Correlation Between Characteristic Host, Physics Environment and Health Service to Dengue Hemorrhagic Fever (Dhf) in Working Area of Public Health Center of Talang Ubi Pendopo in 2012

Background : DHF in Indonesia included A category in the stratification by WHO indicate high rates of hospitalization and deaths due to DHF. Preliminary survey which has been conducted showed in Working Area of Public Health Centre DHF cases is high 51 cases during 2011,. Therefore, the aim of this study was to identifiy the correlation between Characteristics Host, Physics Environment and Health Service to DHF in Working Area of Public Health Centre of Talang Ubi in period of 2012. Method : Used analytical survey study with cross sectional approach. Data collection was conducted by interview and observation using questionnaire and using checklist. The data were analyzed by method of univariate and bivariate with chi square analysis. The number of samples in this study were 85 head of household in Working Area of Public Health Centre of Talang Ubi Pendopo with Sampling Technique used is Simple Random Sampling Techniques. Resulst : From total of six variables, three variables associated with DHF, that are age (p-value=0.002, PR=4.383), physics environment (p-value=0.001, PR=4.750), and health service (p-value=0.022, PR=2.936), while sex (p-value=0.996, PR=1.002), education (p-value=0.093, PR=2.182), and job (p-value=0.216, PR=1.766) has no correlation to the incidence of DHF. Conclution : Public Health Centre of Talang Ubi need to improve health service through promotion and prevention to reduce the transmission and DHF case, improve support of health workers to implement the DHF programs with the best, and the society should also support by improving the environment around the house so as not to be a breeding place of Aedes aegypti and implement the PSN-Aedes aegypti

Extreme nonlinear electrodynamics in metamaterials with very small linear dielectric permittivity

We consider a sub-wavelength periodic layered medium whose slabs are filled by arbitrary linear metamaterials and standard nonlinear Kerr media and we show that the homogenized medium behaves as a Kerr medium whose parameters can assume values not available in standard materials. Exploiting such a parameter availability, we focus on the situation where the linear relative dielectric permittivity is very small thus allowing the observation of the extreme nonlinear regime where the nonlinear polarization is comparable with or even greater than the linear part of the overall dielectric response. The behavior of the electromagnetic field in the extreme nonlinear regime is very peculiar and characterized by novel features as, for example, the transverse power flow reversing. In order to probe the novel regime, we consider a class of fields (transverse magnetic nonlinear guided waves) admitting full analytical description and we show that these waves are allowed to propagate even in media with $\epsilon0$ since the nonlinear polarization produces a positive overall effective permittivity. The considered nonlinear waves exhibit, in addition to the mentioned features, a number of interesting properties like hyper-focusing induced by the phase difference between the field components.Comment: 12 pages, 7 figure

Optically induced metal-to-dielectric transition in Epsilon-Near-Zero metamaterials

This work was supported by the EPSRC grant EP/ J004200/1. D.F. acknowledges financial support from the European Research Council under the European Union Seventh Framework Programme (FP/2007-2013)/ERC GA 306559 and EPSRC (UK, Grant No. EP/J00443X/1). L.C. and M.C. acknowledge the support from the People Programme (Marie Curie Actions) of the European Union’s FP7 Programme THREEPLE (GA 627478) and KOHERENT (GA 299522). A.C. and C.R. acknowledge support from U.S. Army International Technology Center Atlantic for financial support (Grant No. W911NF-14-1-0315).Epsilon-Near-Zero materials exhibit a transition in the real part of the dielectric permittivity from positive to negative value as a function of wavelength. Here we study metal-dielectric layered metamaterials in the homogenised regime (each layer has strongly subwavelength thickness) with zero real part of the permittivity in the near-infrared region. By optically pumping the metamaterial we experimentally show that close to the Epsilon-Near-Zero (ENZ) wavelength the permittivity exhibits a marked transition from metallic (negative permittivity) to dielectric (positive permittivity) as a function of the optical power. Remarkably, this transition is linear as a function of pump power and occurs on time scales of the order of the 100 fs pump pulse that need not be tuned to a specific wavelength. The linearity of the permittivity increase allows us to express the response of the metamaterial in terms of a standard third order optical nonlinearity: this shows a clear inversion of the roles of the real and imaginary parts in crossing the ENZ wavelength, further supporting an optically induced change in the physical behaviour of the metamaterial.Publisher PDFPeer reviewe

Zonal shear and super-rotation in a magnetized spherical Couette flow experiment

We present measurements performed in a spherical shell filled with liquid sodium, where a 74 mm-radius inner sphere is rotated while a 210 mm-radius outer sphere is at rest. The inner sphere holds a dipolar magnetic field and acts as a magnetic propeller when rotated. In this experimental set-up called DTS, direct measurements of the velocity are performed by ultrasonic Doppler velocimetry. Differences in electric potential and the induced magnetic field are also measured to characterize the magnetohydrodynamic flow. Rotation frequencies of the inner sphere are varied between -30 Hz and +30 Hz, the magnetic Reynolds number based on measured sodium velocities and on the shell radius reaching to about 33. We have investigated the mean axisymmetric part of the flow, which consists of differential rotation. Strong super-rotation of the fluid with respect to the rotating inner sphere is directly measured. It is found that the organization of the mean flow does not change much throughout the entire range of parameters covered by our experiment. The direct measurements of zonal velocity give a nice illustration of Ferraro's law of isorotation in the vicinity of the inner sphere where magnetic forces dominate inertial ones. The transition from a Ferraro regime in the interior to a geostrophic regime, where inertial forces predominate, in the outer regions has been well documented. It takes place where the local Elsasser number is about 1. A quantitative agreement with non-linear numerical simulations is obtained when keeping the same Elsasser number. The experiments also reveal a region that violates Ferraro's law just above the inner sphere.Comment: Phys Rev E, in pres

Divergent mathematical treatments in utility theory

In this paper I study how divergent mathematical treatments affect mathematical modelling, with a special focus on utility theory. In particular I examine recent work on the ranking of information states and the discounting of future utilities, in order to show how, by replacing the standard analytical treatment of the models involved with one based on the framework of Nonstandard Analysis, diametrically opposite results are obtained. In both cases, the choice between the standard and nonstandard treatment amounts to a selection of set-theoretical parameters that cannot be made on purely empirical grounds. The analysis of this phenomenon gives rise to a simple logical account of the relativity of impossibility theorems in economic theory, which concludes the paper

Particle Energies and Filling Fractions of Radio Bubbles in Cluster Cores

Using Chandra images of cluster cores with clear radio bubbles, we have determined k, which is the ratio of the total particle energy to that of the electrons radiating between 10 MHz and 10 GHz. Radiative and dynamical constraints on the bubbles indicate that the ratio of the energy factor, k, to the volume filling factor, f, lies within the range 1 < k/f < 1000. Assuming pressure equilibrium between the radio-emitting plasma and the surrounding X-ray gas, none of the lobes have equipartition between relativistic particles and magnetic field. There is no evidence for any dependence of the upper limit of the k/f ratio on any physical parameter of the cluster or the radio source. The distribution of the upper limit on k/f appears to be bimodal, the value for some clusters being ~3 and for the others ~300. We show that this is may due to the composition of the jet which forms the bubbles, the variation in the volume filling fraction or variation in the amount of re-acceleration occurring in the bubble.Comment: 12 pages, 9 figures; accepted for publication in MNRA