Separation of Variables for a Lattice Integrable System and the Inverse Problem

We investigate the relation between the local variables of a discrete integrable lattice system and the corresponding separation variables, derived from the associated spectral curve. In particular, we have shown how the inverse transformation from the separation variables to the discrete lattice variables may be factorized as a sequence of canonical transformations.     

Raman imaging and stress quantification in self‐assembled graphene oxide fiber ‘Latin Letters’

To probe the intrinsic stress distribution in terms of spatial Raman shift (ω) and change in the phonon linewidth (Γ), here we analyze self‐assembled graphene oxide fibers (GOF) ‘Latin letters’ by confocal Raman spectroscopy. The self‐assembly of GOF ‘Latin letters’ has been explained through surface tension, π–π stacking, van der Waals interaction at the air–water interface and by systematic time‐dependent investigation using field emission scanning electron microscopy analysis. Intrinsic residual stress due to structural joints and bending is playing a distinct role affecting the E_2g mode (G band) at and away from the physical interface of GOF segments with broadening of phonon linewidth, indicating prominent phonon softening. Linescan across an interface of the GOF ‘letters’ reveals Raman shift to lower wavenumber in all cases but more so in ‘Z’ fiber exhibiting a broader region. Furthermore, intrinsic stress homogeneity is observed for ‘G’ fiber distributed throughout its curvature with negligible shift corresponding to E_2g mode vibration. This article demonstrates the significance of morphology in stress distribution across the self‐assembled and ‘smart‐integrable’ GOF ‘Latin letters’. Copyright © 2016 John Wiley & Sons, Ltd.     

Reciprocal Ontological Models Show Indeterminism Comparable to Quantum Theory

We show that within the class of ontological models due to Harrigan and Spekkens, those satisfying preparation-measurement reciprocity must allow indeterminism comparable to that in quantum theory. Our result implies that one can design quantum random number generator, for which it is impossible, even in principle, to construct a reciprocal deterministic model.     

Synthesis,structural and electrical properties of Ti modified Bi2Sn2O7 pyrochlore

Polycrystalline ceramic samples of Bi₂Sn_2−xTi_xO₇ (x=0.00, 0.2, 0.4, 0.6 and 0.8) have been synthesized by standard high temperature solid state reaction method. The effect of homovalent cation (titanium) substitution on the Sn-site on the structural and electrical properties of the pure Bi₂Sn₂O₇ ceramic have been studied by X-ray diffraction followed by SEM, dielectric and dc conductivity studies. The structural analysis indicates that the increase of titanium contents do not lead to any secondary phase. The frequency and temperature dependent dielectric studies have been carried out. It is found that the Ti doping reduces the material particle size. The size of the particles are strongly influenced by the addition of titanium to the system. The substitution of Ti for Sn ions affected the degree of disorder and modified the dielectric properties leading to more resistive ceramic compounds. The activation energies of all the compounds were calculated using the relation σ=σ₀exp(−Ea/kT).     

Mach-Zehnder interferometer-based tree architecture for all-optical logic and arithmetic operations

Interferometric devices for optical processing have been of great interest in recent years. Semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer (MZI) has already taken a significant role in the field of ultra-fast all-optical signal processing. Optical tree architecture (OTA) provides important contributions in optical interconnecting networks. In this communication, we have tried to exploit the advantages of both OTA and SOA-based MZI switches. We have proposed SOA-MZI-based tree architecture, a new and alternative scheme, for integrated all-optical logic and arithmetic operations. This architecture can enable one to perform all-optical processing of signals, including two input logic operations, half-adder, full-adder, full-subtractor, one-bit data comparator, etc.     

Observation of the exchange spring behavior in hard-soft-ferrite nanocomposite

Nanocomposite of hard (BaFe₁₂O₁₉) and soft ferrite (Ni_0.8Zn_0.2Fe₂O₄) are prepared by the mixing of the individual ferrite components at appropriate ratio and subsequent heat treatment. Initially the microstructure of the individual phases is controlled by suitable processing. We have observed the exchange spring behavior in the soft-hard ferrite composite for the first time by tailoring the particle size of the individual phases and by suitable thermal treatment of the composite. It is found that the exchange interaction dominates over the dipolar interaction for smaller particle sizes of the soft ferrite. The magnetization of the composite showed hysteresis loop that is characteristic of the exchange spring system. This gives experimental proof for some theoretical modeling as well as paves way for developing magnet with higher (BH)_max product based on ferrites.     

On the absence of shear cracking and grain boundary cavitation in secondary tensile regions of Ti–6Al–4V–0.1B alloy during hot (α + β)-compression

Deformation instabilities, such as shear cracking and grain boundary cavitation, which are observed in the secondary tensile region of Ti–6Al–4V alloy during compressive deformation in the (α?+?β)-phase field, do not form in Ti–6Al–4V–0.1B alloy when processed under the same conditions. This has been attributed to the microstructural modifications, e.g. the absence of grain boundary α and adjacent grain boundary retained β layers and a lower proportion of 90^o-misoriented α-colonies that occur with boron addition.     

Torsion and entropy driven denaturation of DNA

A unified theory of the denaturation transition having torsion energy as the control parameter has been formulated here in the framework of the mapping of a DNA molecule onto a Heisenberg spin system. The torsion energy incorporates the torque, tension and temperature, the latter being associated with the twist angle. The denaturation transition can be mapped onto the quantum phase transition induced by a quench when the temperature effect is incorporated in the quench time and torsion takes the role of the external field. The denaturation transition occurs when the entanglement entropy of the spin system vanishes.     

Unsharp spin observables, non-locality and Fry, Walther and Li experiment

Recently it has been demonstrated that Bell inequalities for spin 1/2 particles must be modified if unsharp spin observables are considered, and furthermore, the modified Bell inequalities may not be violated by quantum mechanics if the observables are sufficiently unsharp. In case of massive particles there may be more imperfection than seems to appear in the photon EPR experiments. So the experiment proposed by Fry, Walther and Li can place experimental limits on the unsharpness of spin variables. It sheds new light on the much debated issues like non-local correlations in quantum mechanics.