Yang-Baxter algebra and generation of quantum integrable models

An operator deformed quantum algebra is discovered exploiting the quantum Yang-Baxter equation with trigonometric R-matrix. This novel Hopf algebra along with its $q \to 1$ limit appear to be the most general Yang-Baxter algebra underlying quantum integrable systems. Three different directions of application of this algebra in integrable systems depending on different sets of values of deforming operators are identified. Fixed values on the whole lattice yield subalgebras linked to standard quantum integrable models, while the associated Lax operators generate and classify them in an unified way. Variable values construct a new series of quantum integrable inhomogeneous models. Fixed but different values at different lattice sites can produce a novel class of integrable hybrid models including integrable matter-radiation models and quantum field models with defects, in particular, a new quantum integrable sine-Gordon model with defect.Comment: 13 pages, revised and bit expanded with additional explanations, accepted for publication in Theor. Math. Phy

Electron transport and thermoelectric properties of layered perovskite LaBaCo2O5.5

We have investigated the systematic transport properties of the layered 112-type cobaltite LaBaCo2O5.5 by means of electrical resistivity, magnetoresistance, electroresistance and thermoelectric measurements in various conditions. In order to understand the complex conduction mechanism of LaBaCo2O5.5, the transport data have been analyzed using different theoretical models. The system shows semiconductor-semiconductor like transition (TSC) around 326K, corresponding to ferromagnetic transition and in the low temperature region resistivity data follows the Motts variable range hopping model. Interestingly, near and below the room temperature this compound depicts significant change in electro- and magnetoresistance behavior, the latter one is noteworthy near the magnetic phase boundary. The temperature dependence of thermopower, S(T), exhibits p-type polaronic conductivity in the temperature range of 60-320K and reaches a maximum value of 303 uV/K (at 120K). In the low temperature AFM region, the unusual S(T) behavior, generally observed for the cobaltite series LnBaCo2O5.5 (Ln = Rare Earth), is explained by the electron magnon scattering mechanism as previously described for perovskite manganites.Comment: 18 pages including fig

A Reaction Diffusion Model Of Pattern Formation In Clustering Of Adatoms On Silicon Surfaces

We study a reaction diffusion model which describes the formation of patterns on surfaces having defects. Through this model, the primary goal is to study the growth process of Ge on Si surface. We consider a two species reaction diffusion process where the reacting species are assumed to diffuse on the two dimensional surface with first order interconversion reaction occuring at various defect sites which we call reaction centers. Two models of defects, namely a ring defect and a point defect are considered separately. As reaction centers are assumed to be strongly localized in space, the proposed reaction-diffusion model is found to be exactly solvable. We use Green's function method to study the dynamics of reaction diffusion processes. Further we explore this model through Monte Carlo (MC) simulations to study the growth processes in the presence of a large number of defects. The first passage time statistics has been studied numerically. Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License. [http://dx.doi.org/10.1063/1.4757592]Microelectronics Research Cente

Interfacial contribution to the dielectric response in semiconducting LaBiMn4/3Co2/3O6

Impedance measurements have been performed on a sintered polycrystalline sample of the perovskite LaBiMn4/3Co2/3O6. Colossal dielectric permittivity often is measured in this class of semiconducting materials as a result of extrinsic factors. Our results show that a large offset in the capacitance, measured on a series of samples with different thickness, is due to the interfacial polarization. This contribution then can be removed from the data, creating a general procedure for dielectric measurements in semiconducting samples.Comment: 13 pages, 4 figure

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

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