<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

Shiv Nadar University

(SoNS) School of Natural Sciences

Hilbert-Schmidt distance is one of the prominent distance measures in quantum information theory which finds applications in diverse problems, such as construction of entanglement witnesses, quantum algorithms in machine learning, and quantum-state tomography. In this work, we calculate exact and compact results for the mean-square Hilbert-Schmidt distance between a random density matrix and a fixed density matrix, and also between two random density matrices. In the course of derivation, we also obtain corresponding exact results for the distance between a Wishart matrix and a fixed Hermitian matrix, and two Wishart matrices. We verify all our analytical results using Monte Carlo simulations. Finally, we apply our results to investigate the Hilbert-Schmidt distance between reduced density matrices generated using coupled kicked tops. © 2020 American Physical Society.

Physics

Fulltext

Physical Review A

Wishart and random density matrices: Analytical results for the mean-square Hilbert-Schmidt distance

Li7 nuclear magnetic resonance and terahertz (THz) spectroscopies are used to probe magnetic excitations and their field dependence in the hyperhoneycomb Kitaev magnet $\beta$-Li2IrO3. Spin-lattice relaxation rate (1/T1) measured down to 100 mK indicates the gapless nature of the excitations at low fields (below Hc≃2.8 T), in contrast to the gapped magnon excitations found in the honeycomb Kitaev magnet $\alpha$-RuCl3 at zero applied magnetic field. At higher temperatures in $\beta$-Li2IrO3, 1/T1 passes through a broad maximum without any clear anomaly at the Ne{\'{e}}l temperature TN≃38 K, suggesting the abundance of low-energy excitations that are indeed observed as two peaks in the THz spectra; both correspond to zone-center magnon excitations. At higher fields (above Hc), an excitation gap opens and a redistribution of the THz spectral weight is observed without any indication of an excitation continuum, in contrast to $\alpha$-RuCl3 where an excitation continuum was reported.

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Physical Review B

Field evolution of low-energy excitations in the hyperhoneycomb magnet $\beta$-Li2IrO3

Max-plus algebra has been applied to several fields like matrix algebra, cryptography, transportation, manufacturing, information technology and study of discrete event systems like subway traffic networks, parallel processing systems, telecommunication networks for many years. In this paper, we discuss various optimization problem using methods based on max-plus algebra, which has maximization and addition as its basic arithmetic operations. We present some sub-classes of mathematical optimization problems like linear programming, convex quadratic programming problem, fractional programming problem, bimatrix game problem and some classes of stochastic game problem in max algebraic framework and discuss various connections between max-plus algebra and optimization. © 2020, Springer Nature Singapore Pte Ltd.

Mathematics

Springer Proceedings in Mathematics and Statistics

Max Plus Algebra, Optimization and Game Theory

Microwave synthesis was optimized for preparing novel monoclinic Tin-doped barium niobate ceramics (Ba1-xSnxNb2O6; x = 0.0, 0.01, 0.05, 0.1, 0.2, 0.3) BSN. The intensity of monoclinic phase formation was observed to decrease on increasing tin as dopant indicating decreased crystallinity. Strained crystalline phase was observed in undoped sample that became severe on doping tin. Monoclinic metal alloy Sn2O3 formation was confirmed on increasing tin doping beyond 5\%. Electronic configuration of tin (II) oxide supports the local site-wise monoclinic disorder in crystal structure due to sterically active lone pair. Such a disorder arranges increased number of degenerate energy states and reduce effective energy gap between conduction band minimum and valence band maximum. All BSN compositions were investigated for monoclinic phase stabilization, ultra-violet absorption, dielectric response, raman modes and type of carrier concentration along with hall resistivity. All measurements possessed inflexion corresponding to 5\% tin doping indicating successful site substitution and estimated Sn2O3 metal formation beyond this. The values of reducing optical energy band gap, transparency to visible spectrum, hall resistivity and dc conductivity indicated utility of these materials as a target for growing transparent conducting oxide (TCO) films for substituting well-known indium tin oxide (ITO). © 2019

Journal of Alloys and Compounds

Microwave derived monoclinic Ba1-xSnxNb2O6 materials as an alternative of ITO

A new library of pyrido-pyrrolidine hybrid compounds were designed, developed and screened for their antidiabetic property with α-glucosidase. The design is based on preliminary screening of key fragments identified from literature reported α-glucosidase inhibitors and antidiabetic compounds. The most active fragments were stitched to provide a pyrido-pyrrolidine hybrid molecule as a new motif. A library of these compounds were synthesized and screened against a series of α-glycosidases. Subsequently, compound 3k was the most efficacious analog with IC50 of 0.56 μM. Photoluminescence study and circular dichroism experiments indicated that compound 3k modulates the primary and secondary structure of the enzyme. It successfully brings down the fasting blood glucose level for streptozotocin (STZ, 70 mg/kg, Intraperitoneal) induced type I diabetic male Sprague-Dawley rats (250–320 g). At lower concentration, compound 3k slightly stimulates proliferation of BRIN-BD11 (α-glucose responsive beta cells from rat pancreas islets that secretes insulin) cells. © 2020 Elsevier Masson SAS

Chemistry

European Journal of Medicinal Chemistry

Discovery of novel pyrido-pyrrolidine hybrid compounds as alpha-glucosidase inhibitors and alternative agent for control of type 1 diabetes

Hume-Rothery rules along with Vegard's law form the basis of systematic doping variation resulting into similar changes in unit cell parameters and volume. Many recent reports have highlighted positive–negative departure from Vegard's law in binary semiconducting systems and a few oxide alloys as well. The current work targets investigations on the missing response of bismuth molybdate on low tungsten doping onto molybdenum sites (Bi2Mo1−xWxO6). Bismuth molybdate and bismuth tungstate have been widely reported for lattice oxygen migration-driven photocatalytic response and pressure-sensitive Raman scattering. Octahedral tilting in low-tungsten-doped Bi2Mo0.94W0.06O6 carries an interesting lattice oxygen folding toward a–c plane. As a result, unit cell polarity increases drastically and becomes a source for intense Raman scattering phase that is normally observable at pressures around 8.3 GPa. An interesting departure from Vegard's law behavior at around 5–6\% tungsten doping confirms nearly identical unit cell structure rather than mix unit cell-based alloy formation. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Physica Status Solidi (B) Basic Research

Deviations from Vegard's Law and Intense Raman Scattering in Low-Doped Bi2Mo1−xWxO6 (x = 0–10%) Ceramics

Water is the most prominent solvent. The unique properties of water are rooted in the dynamical hydrogen-bonded network. While TeraHertz (THz) radiation can probe directly the collective molecular network, several open issues remain about the interpretation of these highly anharmonic, coupled bands. In order to address this problem, we need intense THz radiation able to drive the liquid into the nonlinear response regime. Firstly, in this study, we summarize the available brilliant THz sources and compare their emission properties. Secondly, we characterize the THz emission by Gallium Phosphide (GaP), 2-[3-(4-hydroxystyryl)-5,5-dimethylcyclohex-2-enylidene]malononitrile (OH1), and 4-N, N-dimethylamino-4′-N′-methyl-stilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS) crystals pumped by an amplified near-infrared (NIR) laser with tunable wavelength. We found that both OH1 as well as DSTMS could convert NIR laser radiation between 1200 and 2500 nm into THz radiation with high efficiency (&gt; 2 x 10-4), resulting in THz peak fields exceeding 0.1 MV/cm for modest pump excitation (~ mJ/cm2). DSTMS emits the broadest spectrum, covering the entire bandwidth of our detector from ca. 0.5 to ~7 THz, also at a laser wavelength of 2100 nm. Future improvements will require handling the photothermal damage of these delicate organic crystals, and increasing the THz frequency. © 2020 by the authors.

Materials

Towards intense THz spectroscopy on water: Characterization of optical rectification by GaP, OH1, and DSTMS at OPA wavelengths

An environmentally compatible organic solar cell (OSC) has potential to build a global clean energy infrastructure for the world. However, much less attention has been focused on the structures sourced from greener origins to enhance the sustainability aspect of these devices. Herein, we report a rational design, synthesis, and characterization of donor (D)-acceptor (A)-based green organic small molecules, consisting of difluoro-2,1,3-benzothiadiazole (BTF2) as the acceptor, with thiophene (T) and renewable resource materials, cardanol (C) and guaiacol (G) as the donor materials. The reference molecule, abbreviated as T4BTF2, is fully petro-sourced, while C2T2BTF2 and G2T2BTF2 are partly renewable origin molecules. Broad and strong absorption characteristics ranging from 300 to 600 nm along with high thermal stability are supportive for utility of the green origin small molecules in solar cells. Density functional theory (DFT) calculations revealed that G2T2BTF2 is more highly planar than C2T2BTF2 due to the difference in the positioning of the alkyl/alkoxy chain. With bulk heterojunction OSCs with PC71BM as the acceptor, G2T2BTF2 exhibited a high Voc of 0.83 V among all the analyzed small molecules. When compared with the reference molecule T4BTF2, G2T2BTF2 showed a high PCE of 5.56\% with a high Jsc of 10.98 mA/cm2 and FF of 0.61, whereas the PCEs of T4BTF2 and C2T2BTF2 are 3.98\% and 3.23\%, respectively. Our work demonstrates a rational approach to synthesize and develop green organic semiconductors using the biofeedstock derived starting materials for realizing efficient and environment compatible OSCs. Copyright © 2020 American Chemical Society.

ACS Sustainable Chemistry and Engineering

Cardanol- And Guaiacol-Sourced Solution-Processable Green Small Molecule-Based Organic Solar Cells

This review is intended for readers who want to have a quick understanding on the theoretical underpinnings of coherent states and squeezed states which are conventionally generated from the prototype harmonic oscillator but not always restricting to it. Noting that the treatments of building up such states have a long history, we collected the important ingredients and reproduced them from a fresh perspective but refrained from delving into detailed derivation of each topic. By no means we claim a comprehensive presentation of the subject but have only tried to recapture some of the essential results and pointed out their interconnectivity. © 2020 World Scientific Publishing Company.

International Journal of Modern Physics A

A pedestrian introduction to coherent and squeezed states

<p>A truncation of a Haar distributed orthogonal random matrix gives rise to a matrix whose eigenvalues are either real or complex conjugate pairs, and are supported within the closed unit disk. This is also true for a product Pm of m independent truncated orthogonal random matrices. One of most basic questions for such asymmetric matrices is to ask for the number of real eigenvalues. In this paper, we will exploit the fact that the eigenvalues of Pm form a Pfaffian point process to obtain an explicit determinant expression for the probability of finding any given number of real eigenvalues. We will see that if the truncation removes an even number of rows and columns from the original Haar distributed orthogonal matrix, then these probabilities will be rational numbers. Finally, based on exact finite formulas, we will provide conjectural expressions for the asymptotic form of the spectral density and the average number of real eigenvalues as the matrix dimension tends to infinity. © 2018 Taylor &amp; Francis.</p>