Matter wave switching in Bose-Einstein condensates via intensity redistribution soliton interactions

Using time dependent nonlinear (s-wave scattering length) coupling between the components of a weakly interacting two component Bose-Einstein condensate (BEC), we show the possibility of matter wave switching (fraction of atoms transfer) between the components via shape changing/intensity redistribution (matter redistribution) soliton interactions. We investigate the exact bright-bright N-soliton solution of an effective one-dimensional (1D) two component BEC by suitably tailoring the trap potential, atomic scattering length and atom gain or loss. In particular, we show that the effective 1D coupled Gross-Pitaevskii (GP) equations with time dependent parameters can be transformed into the well known completely integrable Manakov model described by coupled nonlinear Schr\"odinger (CNLS) equations by effecting a change of variables of the coordinates and the wave functions under certain conditions related to the time dependent parameters. We obtain the one-soliton solution and demonstrate the shape changing/matter redistribution interactions of two and three soliton solutions for the time independent expulsive harmonic trap potential, periodically modulated harmonic trap potential and kink-like modulated harmonic trap potential. The standard elastic collision of solitons occur only for a specific choice of soliton parameters.Comment: 11 pages, 14 figures, 1 tabl

Consequences of self-consistency violations in Hartree-Fock random-phase approximation calculations of the nuclear breathing mode energy

We provide for the first time accurate assessments of the consequences of violations of self-consistency in the Hartree-Fock based random phase approximation (RPA) as commonly used to calculate the energy $E_c$ of the nuclear breathing mode. Using several Skyrme interactions we find that the self-consistency violated by ignoring the spin-orbit interaction in the RPA calculation causes a spurious enhancement of the breathing mode energy for spin unsaturated systems. Contrarily, neglecting the Coulomb interaction in the RPA or performing the RPA calculations in the TJ scheme underestimates the breathing mode energy. Surprisingly, our results for the $^{90}$Zr and $^{208}$Pb nuclei for several Skyrme type effective nucleon-nucleon interactions having a wide range of nuclear matter incompressibility ($K_{nm} \sim 215 - 275$ MeV) and symmetry energy ($J \sim 27 - 37$ MeV) indicate that the net uncertainty ($\delta E_c \sim 0.3$ MeV) is comparable to the experimental one.Comment: Revtex file (11 pages), Accepted for the publication in Phys. Rev.

Feasibility and benefits of laminar flow control on supersonic cruise airplanes

An evaluation was made of the applicability and benefits of laminar flow control (LFC) technology to supersonic cruise airplanes. Ancillary objectives were to identify the technical issues critical to supersonic LFC application, and to determine how those issues can be addressed through flight and wind-tunnel testing. Vehicle types studied include a Mach 2.2 supersonic transport configuration, a Mach 4.0 transport, and two Mach 2-class fighter concepts. Laminar flow control methodologies developed for subsonic and transonic wing laminarization were extended and applied. No intractible aerodynamic problems were found in applying LFC to airplanes of the Mach 2 class, even ones of large size. Improvements of 12 to 17 percent in lift-drag ratios were found. Several key technical issues, such as contamination avoidance and excresence criteria were identified. Recommendations are made for their resolution. A need for an inverse supersonic wing design methodology is indicated

Clinical characteristics and associated factors of cerebral palsy in pediatric population: a tertiary care centre clinicoepidemiological study

Background: Although, a highly prevalent disease, the etiology of cerebral palsy is still poorly understood thereby eluding a definitive prevention strategy. Our study aimed to evaluate the etiological, clinical and prognostic factors associated with cerebral palsy in children of western Rajasthan. Methods: All cases of non-progressive neurological disorder in the age group of 6 months to 14 years were enrolled in the present study. Detailed assessment, CNS examination and related neuroimaging were performed. Statistical analysis was done by standard statistical methods. Results: Maximum number of patients in current study were in the age group of 1-3 years. In our study according to sex, 40 (66.67%) were males and 20 (33.33) were females. Most of the patient in the present study were spastic quadriplegic type (40%) followed by spastic diplegia in 20% cases. As per gross motor function classification system (GMFCS) grading, maximum number of cases were 16 (26.67%) from grade 4. The most common sequelae in cerebral palsy were speech delay in 49 (81.66%) patients. Cortical atrophy was the most commonly (71.73%) seen abnormality on neuroimaging with CT-scan. Conclusions: Cerebral palsy is a non-progressive CNS disorder which has a major physical as well as psychological effects on the children as well as their families. The present study highlights the importance of understanding epidemiological and etiological aspects of the disease in Indian scenario

Constraining the density dependence of symmetry energy from nuclear masses

Empirically determined values of the nuclear volume and surface symmetry energy coefficients from nuclear masses are expressed in terms of density distributions of nucleons in heavy nuclei in the local density approximation. This is then used to extract the value of the symmetry energy slope parameter $L$. The density distributions in both spherical and well deformed nuclei calculated within microscopic framework with different energy density functionals give $L = 59.0 \pm 13.0$ MeV. Application of the method also helps in a precision determination of the neutron skin thickness of nuclei that are difficult to measure accurately.Comment: 6 pages including 3 figures, accepted in Phys. Rev. C (Rapid Comm.

Quantum Frequency Translation of Single-Photon States in Photonic Crystal Fiber

We experimentally demonstrate frequency translation of a nonclassical optical field via the Bragg scattering four-wave mixing process in a photonic crystal fiber (PCF). The high nonlinearity and the ability to control dispersion in PCF enable efficient translation between photon channels within the visible to-near-infrared spectral range, useful in quantum networks. Heralded single photons at 683 nm were translated to 659 nm with an efficiency of $28.6 \pm 2.2$ percent. Second-order correlation measurements on the 683-nm and 659-nm fields yielded $g^{(2)}_{683}(0) = 0.21 \pm 0.02$ and $g^{(2)}_{659}(0) = 0.19 \pm 0.05$ respectively, showing the nonclassical nature of both fields.Comment: 5 pages, 3 figure

Fermionic bright soliton in a boson-fermion mixture

We use a time-dependent dynamical mean-field-hydrodynamic model to study the formation of fermionic bright solitons in a trapped degenerate Fermi gas mixed with a Bose-Einstein condensate in a quasi-one-dimensional cigar-shaped geometry. Due to a strong Pauli-blocking repulsion among spin-polarized fermions at short distances there cannot be bright fermionic solitons in the case of repulsive boson-fermion interactions. However, we demonstrate that stable bright fermionic solitons can be formed for a sufficiently attractive boson-fermion interaction in a boson-fermion mixture. We also consider the formation of fermionic solitons in the presence of a periodic axial optical-lattice potential. These solitons can be formed and studied in the laboratory with present technology.Comment: 7 pages, 7 ps figure

Inverse scattering method for square matrix nonlinear Schr\"odinger equation under nonvanishing boundary conditions

Matrix generalization of the inverse scattering method is developed to solve the multicomponent nonlinear Schr\"odinger equation with nonvanishing boundary conditions. It is shown that the initial value problem can be solved exactly. The multi-soliton solution is obtained from the Gel'fand--Levitan--Marchenko equation.Comment: 25 pages, 2 figures; (v2) title changed, typos in equations corrected, sec.3.1 modified and extende

A review paper on R&D efforts in assessing the traffic noise on highways

In rapidly urbanizing country like India, the transportation sector is growing in a fast pace and the number of vehicles on Indian roads is increasing at a rate of more than 7% per annum. This has led to over crowded roads and pollution. Transportation sector is one of the major contributors to noise in urban area, which contributes 55% of total noise on highway. In view of this, it is essential to study highway noise with respect to various causative factors. Hence, various noise prediction models have been developed, throughout the world to assess its impact on to the society and the human beings. These traffic noise prediction models differ in some respects, but the overall methodology is similar. All the noise prediction models consists of evaluating basic noise levels and making series of adjustments to take into account geometric, traffic flow, barrier data etc. In this paper, noise prediction models of U.S.A. and U.K. (FHWA and CORTON) along with the research efforts on noise in Indian context has been studied and discussed

Traumatic Retrobulbar Haemorrhage: Aetio-pathology and management

Retrobulbar haematoma following blunt orbital trauma is a rare,but potentially serious complication, since it can evolve rapidly from visual impairment to permanent loss of vision. This sight-threatening situation most commonly arises from orbital bleeding accompanying undisplaced fractures of the orbital walls, an event that increases the pressure inside theorbit and results in vascular damage to the optic nerve. The clinical presentation includes pain, exophthalmos with proptosis, and internal ophthalmoplegia, with impairment or loss of the pupillary reXex. A thin-layer orbital CT scan is an essential diagnostic aid. Therapy is based on orbitaldecompression, via different surgical approaches, with the intention of reducing the pressure on the nerve and vascular structures inside the orbit. Emergent management is of utmost importance as any delay between the onset of symptoms and treatment can have a significant effect onrecovery