Quantum bound states for a derivative nonlinear Schrodinger model and number theory

A derivative nonlinear Schrodinger model is shown to support localized N-body bound states for several ranges (called bands) of the coupling constant eta. The ranges of eta within each band can be completely determined using number theoretic concepts such as Farey sequences and continued fractions. For N > 2, the N-body bound states can have both positive and negative momentum. For eta > 0, bound states with positive momentum have positive binding energy, while states with negative momentum have negative binding energy.Comment: Revtex, 7 pages including 2 figures, to appear in Mod. Phys. Lett.

BNKR-1 (Dhiren) – A newly released late duration high-yielding rice variety an alternative to Swarna (MTU 7029) for West Bengal, India

BNKR – I (Dhiren), a new late duration high yielding rice variety developed at Rice Research Station, Bankura, West Bengal, India was released by “State Variety Release Committee” (SVRC), West Bengal in 2011 for cultivation in irrigated late areas of West Bengal, India. Before release as BNKR – I (Dhiren), this rice culture completed three years of national testing (2008-2010) in the designation of CN 1340-76-1-BNKR 23-7-1 (IET 20760) and had been recommended for release in irrigated areas of Bihar and West Bengal under transplanted condition in 46th National Group Meeting on Rice organized by Directorate of Rice Research (ICAR), Hyderabad, India during April 2011. It gave 7.65 to 12.12% yield advantage over national check in national level. Not only that this culture of rice tested extensively in the farm of Rice research Station, Bankura, West Bengal and farmer’s field. It showed 11.64% and 19.30% yield advantage during 2006 and 2007 in observational trial, 10.44 to 14.38% yield advantage in on station yield trial during 2008-2010 and 12.51 to 17.93% yield advantage in farmer’s field during 2009 and 2010 over Swarna (MTU 7029), which is the most popular rice variety of West Bengal. BNKR – I (Dhiren) is non-lodging, non-shattering and late maturing variety (seed to seed : 142 days). It is moderately resistant to leaf blast, neck blast, brown spot, sheath rot and leaf folder. It’s average yield is 5000 – 5500 kg ha-1 . Grain type is short bold. It is expected that BNKR – I (Dhiren) can be able to replace Swarna (MTU 7029), the most popular rice variety of West Bengal, India

Variable parameter resized zero attracting least mean fourth control for grid-tied pv system

This paper presents the variable parameter resized zero attracting least mean fourth (VP-RZA-LMF) control algorithm for grid-tied photovoltaic (PV) system. The proposed control algorithm is superior over the conventional control algorithms in terms of swift response and handling the irregular nature of solar irradiations. The DC bus voltage control is incorporated in voltage source converter (VSC) control. The boost converter utilizes the maximum power point tracking (MPPT) algorithm for producing its gating sequence to keep PV array voltage constant. - BEIESP

NGC 7538 : Multiwavelength Study of Stellar Cluster Regions associated with IRS 1-3 and IRS 9 sources

We present deep and high-resolution (FWHM ~ 0.4 arcsec) near-infrared (NIR) imaging observations of the NGC 7538 IRS 1-3 region (in JHK bands), and IRS 9 region (in HK bands) using the 8.2m Subaru telescope. The NIR analysis is complemented with GMRT low-frequency observations at 325, 610, and 1280 MHz, molecular line observations of H13CO+ (J=1-0), and archival Chandra X-ray observations. Using the 'J-H/H-K' diagram, 144 Class II and 24 Class I young stellar object (YSO) candidates are identified in the IRS 1-3 region. Further analysis using 'K/H-K' diagram yields 145 and 96 red sources in the IRS 1-3 and IRS 9 regions, respectively. A total of 27 sources are found to have X-ray counterparts. The YSO mass function (MF), constructed using a theoretical mass-luminosity relation, shows peaks at substellar (~0.08-0.18 Msolar) and intermediate (~1-1.78 Msolar) mass ranges for the IRS 1-3 region. The MF can be fitted by a power law in the low mass regime with a slope of Gamma ~ 0.54-0.75, which is much shallower than the Salpeter value of 1.35. An upper limit of 10.2 is obtained for the star to brown dwarf ratio in the IRS 1-3 region. GMRT maps show a compact HII region associated with the IRS 1-3 sources, whose spectral index of 0.87+-0.11 suggests optical thickness. This compact region is resolved into three separate peaks in higher resolution 1280 MHz map, and the 'East' sub-peak coincides with the IRS 2 source. H13CO+ (J=1-0) emission reveals peaks in both IRS 1-3 and IRS 9 regions, none of which are coincident with visible nebular emission, suggesting the presence of dense cloud nearby. The virial masses are approximately of the order of 1000 Msolar and 500 Msolar for the clumps in IRS 1-3 and IRS 9 regions, respectively.Comment: 27 pages, 18 figures, 5 tables. Accepted for publication in MNRA

On spin chains and field theories

We point out that the existence of global symmetries in a field theory is not an essential ingredient in its relation with an integrable model. We describe an obvious construction which, given an integrable spin chain, yields a field theory whose 1-loop scale transformations are generated by the spin chain Hamiltonian. We also identify a necessary condition for a given field theory to be related to an integrable spin chain. As an example, we describe an anisotropic and parity-breaking generalization of the XXZ Heisenberg spin chain and its associated field theory. The system has no nonabelian global symmetries and generally does not admit a supersymmetric extension without the introduction of more propagating bosonic fields. For the case of a 2-state chain we find the spectrum and the eigenstates. For certain values of its coupling constants the field theory associated to this general type of chain is the bosonic sector of the Leigh-Strassler deformation of N=4 SYM theory.Comment: 22 pages, Latex; v2. typos correcte

Origin of spin gapless semiconductor behavior in CoFeCrGa: theory and experiment

Despite a plethora of materials suggested for spintronic applications, a new class of materials has emerged, namely spin gapless semiconductors (SGS), which offers potentially more advantageous properties than existing ones. These magnetic semiconductors exhibit a finite band gap for one spin channel and a closed gap for the other. Here, supported by electronic-structure calculations, we report evidence of SGS behavior in equiatomic quaternary CoFeCrGa, having a cubic Heusler (prototype LiMgPdSn) structure but exhibiting chemical disorder (DO3 structure). CoFeCrGa is found to transform from SGS to half-metallic phase under pressure, which is attributed to unique electronic-structure features. The saturation magnetization (M-S) obtained at 8K agrees with the Slater-Pauling rule and the Curie temperature (T-C) is found to exceed 400 K. Carrier concentration (up to 250 K) and electrical conductivity are observed to be nearly temperature independent, prerequisites for SGS. The anomalous Hall coefficient is estimated to be 185 S/cm at 5K. Considering the SGS properties and high T-C, this material appears to be promising for spintronic applications.Despite a plethora of materials suggested for spintronic applications, a new class of materials has emerged, namely spin gapless semiconductors (SGS), which offers potentially more advantageous properties than existing ones. These magnetic semiconductors exhibit a finite band gap for one spin channel and a closed gap for the other. Here, supported by electronic-structure calculations, we report evidence of SGS behavior in equiatomic quaternary CoFeCrGa, having a cubic Heusler (prototype LiMgPdSn) structure but exhibiting chemical disorder (DO3 structure). CoFeCrGa is found to transform from SGS to half-metallic phase under pressure, which is attributed to unique electronic-structure features. The saturation magnetization (M-S) obtained at 8K agrees with the Slater-Pauling rule and the Curie temperature (T-C) is found to exceed 400 K. Carrier concentration (up to 250 K) and electrical conductivity are observed to be nearly temperature independent, prerequisites for SGS. The anomalous Hall coefficient is estimated to be 185 S/cm at 5K. Considering the SGS properties and high T-C, this material appears to be promising for spintronic applications.92415Agências de fomento estrangeiras apoiaram essa pesquisa, mais informações acesse artig

Resonant forcing of select degrees of freedom of multidimensional chaotic map dynamics

We study resonances of multidimensional chaotic map dynamics. We use the calculus of variations to determine the additive forcing function that induces the largest response, that is, the greatest deviation from the unperturbed dynamics. We include the additional constraint that only select degrees of freedom be forced, corresponding to a very general class of problems in which not all of the degrees of freedom in an experimental system are accessible to forcing. We find that certain Lagrange multipliers take on a fundamental physical role as the efficiency of the forcing function and the effective forcing experienced by the degrees of freedom which are not forced directly. Furthermore, we find that the product of the displacement of nearby trajectories and the effective total forcing function is a conserved quantity. We demonstrate the efficacy of this methodology with several examples.Comment: 11 pages, 3 figure

Stochastic Models on a Ring and Quadratic Algebras. The Three Species Diffusion Problem

The stationary state of a stochastic process on a ring can be expressed using traces of monomials of an associative algebra defined by quadratic relations. If one considers only exclusion processes one can restrict the type of algebras and obtain recurrence relations for the traces. This is possible only if the rates satisfy certain compatibility conditions. These conditions are derived and the recurrence relations solved giving representations of the algebras.Comment: 12 pages, LaTeX, Sec. 3 extended, submitted to J.Phys.