Collisionless energy absorption in the short-pulse intense laser-cluster interaction

In a previous Letter [Phys. Rev. Lett. 96, 123401 (2006)] we have shown by means of three-dimensional particle-in-cell simulations and a simple rigid-sphere model that nonlinear resonance absorption is the dominant collisionless absorption mechanism in the intense, short-pulse laser cluster interaction. In this paper we present a more detailed account of the matter. In particular we show that the absorption efficiency is almost independent of the laser polarization. In the rigid-sphere model, the absorbed energy increases by many orders of magnitude at a certain threshold laser intensity. The particle-in-cell results display maximum fractional absorption around the same intensity. We calculate the threshold intensity and show that it is underestimated by the common over-barrier ionization estimate.Comment: 12 pages, 13 figures, RevTeX

Seed yield of linseed varieties grown as ‘paira’ crop as influenced by dates of sowing

Linseed is an industrial crop cultivated for its seeds, fibres and oil purpose. Linseed crop can met their requirement i.e. moisture and nutritional demand from stored soil moisture and residual fertility status in "utera? or "paira? system of cropping. On the basis of this fact an experiment was conducted on “Seed yield of linseed varieties grown as paira crop as influenced by dates of sowing” in red and laterite zone of West Bengal during rabi season of 2012-13 and 2013-14 at Rice Research Station, Bankura, West Bengal, India. Poor in organic matter content, available phosphate and bases, hard structure of iron and aluminium patterned as honeycomb are present in the subsurface regions of the profiles and kaolinite is the predominant clay minerals of red and lateritic zone (western part) of West Bengal. This experiment was laid out in a split-plot design with three replications and compared two factors (dates of sowing and linseed varieties). Objective was identifying the optimum date of sowing and suitable linseed varieties grown as „paira? crop under changed climate in red and laterite zone of West Bengal. The experimental results revealed that the highest seed yield (534 kg ha-1 as pooled value) was recorded from the treatment D1 i.e. linseed sown on 15th November. The lowest seed yield (489.2 kg ha-1 as pooled value) was obtained with treatment D3 i.e. linseed sown on 29th November. Among linseed varieties, T-397 has yielded highest seed yield (573.4 kg ha-1 as pooled value). Lowest seed yield (409. 3 kg ha-1 as pooled data) was recorded from Neela variety. From the present study it may be concluded that linseed sown on 15th November is the best time and T-397 is the suitable linseed variety grown as "paira? crop under changed climate in red and laterite zone of West Bengal

Linear stability analysis of capillary instabilities for concentric cylindrical shells

Motivated by complex multi-fluid geometries currently being explored in fibre-device manufacturing, we study capillary instabilities in concentric cylindrical flows of $N$ fluids with arbitrary viscosities, thicknesses, densities, and surface tensions in both the Stokes regime and for the full Navier--Stokes problem. Generalizing previous work by Tomotika (N=2), Stone & Brenner (N=3, equal viscosities) and others, we present a full linear stability analysis of the growth modes and rates, reducing the system to a linear generalized eigenproblem in the Stokes case. Furthermore, we demonstrate by Plateau-style geometrical arguments that only axisymmetric instabilities need be considered. We show that the N=3 case is already sufficient to obtain several interesting phenomena: limiting cases of thin shells or low shell viscosity that reduce to N=2 problems, and a system with competing breakup processes at very different length scales. The latter is demonstrated with full 3-dimensional Stokes-flow simulations. Many $N > 3$ cases remain to be explored, and as a first step we discuss two illustrative $N \to \infty$ cases, an alternating-layer structure and a geometry with a continuously varying viscosity

Quantum Kelvin-Helmholtz instability in phase-separated two-component Bose-Einstein condensates

We theoretically study the Kelvin-Helmholtz instability in phase-separated two-component Bose-Einstein condensates using the Gross-Pitaevskii and Bogoliubov-de Gennes models. A flat interface between the two condensates is shown to deform into sawtooth or Stokes-like waves, leading to the formation of singly quantized vortices on the peaks and troughs of the waves. This scenario of interface instability in quantum fluids is quite different from that in classical fluids.Comment: 5 pages, 4 figure

An explanation for metallicity effects on X-ray Binary properties

We show that irradiation induced stellar winds can explain two important metallicity effects in X-ray binaries - the higher numbers and the softer spectra of the X-ray binaries in metal rich globular clusters compared to the metal poor ones. As has been previously noted by Iben, Tutukov and Fedorova, the winds should be stronger at lower metallicity due to less efficient line cooling. This will speed up the evolution of the LMXBs in metal poor clusters, hence reducing their numbers. These winds can also provide extra material near the accreting object which may create an intrinsic absorber to harden the X-ray spectra of the metal poor cluster systems relative to the metal rich ones, as suggested by observations. We outline some additional observational predictions of the model.Comment: 6 pages, no figures, accepted to Ap

Quantum integrable multi atom matter-radiation models with and without rotating wave approximation

New integrable multi-atom matter-radiation models with and without rotating wave approximation (RWA) are constructed and exactly solved through algebraic Bethe ansatz. The models with RWA are generated through ancestor model approach in an unified way. The rational case yields the standard type of matter-radiaton models, while the trigonometric case corresponds to their q-deformations. The models without RWA are obtained from the elliptic case at the Gaudin and high spin limit.Comment: 9 pages, no figure, talk presented in int. conf. NEEDS04 (Gallipoli, Italy, July 2004

Boron availability in relation to some important soil chemical properties in acid soils of Cooch Behar district, West Bengal

In the present study, we investigated the distribution of soil available boron and its relationship with some soil properties in the samples collected from different locations in acidic alluvial soils of Cooch Behar district in West Bengal during 2013-2014. For the study about two hundred fifty (250) georeferenced surface soil samples covering 11 blocks of the districts were collected with the help of a global positioning system (GPS). The soil results revealed that pH of the analyzed samples varied from 4.91-7.28 (mean value 5.68) which indicated that soils of the district were in the acidic to slightly acidic in reaction. Organic carbon content of the soils varied from 0.42 to 1.62 % with a mean value of 0.96 % and about 93.7 % of the samples were high whereas about 5.2 and 1.2 % of the samples analyzed were in medium and low category, respectively. Results also indicated that the available B content in the soils of the districts ranged from 0.04 to 3.87 mg kg-1 with a mean value of 0.51 mg kg-1 and about 38.26 % soil samples were classified under low, whereas, 3.58 and 0.35 % samples were categorized as medium and high in available B content. It was further indicated that the content of available B in soil was positively correlated with organic carbon (r = 0.170**) and negatively correlated with pH (r = -0.021). Organic carbon status was also found to be positively and non significantly correlated with soil pH (r = 0.062). The results of the study would be immensely helpful for the extension workers to recommended B application considering pH and organic carbon status in acidic soils of the district for a profitable crop production

Effects of non-denumerable fixed points in finite dynamical systems

The motion of a spinning football brings forth the possible existence of a whole class of finite dynamical systems where there may be non-denumerably infinite number of fixed points. They defy the very traditional meaning of the fixed point that a point on the fixed point in the phase space should remain there forever, for, a fixed point can evolve as well! Under such considerations one can argue that a free-kicked football should be non-chaotic.Comment: This paper is a replaced version to modify the not-so-true claim, made unknowingly in the earlier version, of being first to propose the peculiar dynamical systems as described in the paper. With respect to the original workers, we present here our original finding

Algebraic approach in unifying quantum integrable models

A novel algebra underlying integrable systems is shown to generate and unify a large class of quantum integrable models with given $R$-matrix, through reductions of an ancestor Lax operator and its different realizations. Along with known discrete and field models a new class of inhomogeneous and impurity models are obtained.Comment: Revtex, 6 pages, no figure, revised version to be published in Phys. Rev. Lett., 199