Browsing Department of Physics & Materials Science by Title
Now showing items 111-130 of 158
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Quadrature fluctuation energy, effective Hamiltonians, quasi-particle modes and quantum phase transitions in the Rabi and Dicke models
(Research gate, 2017)The main purpose of this article is to provide a simple physically motivated exact analytical procedure for determining effective Rabi and Dicke Hamiltonians, which have so far posed serious challenges in studies of ... -
Quantum thermodynamics of a strongly interacting bose-fermi mixture in a three-dimensional anharmonic potential
(Research gate, 2016)ABSTRACT Thermodynamic properties of Bose-Fermi mixture at ultra-low temperatures were studied using perturbation theory in three Cartesian coordinates. The Hamiltonian for the mixture was developed in terms of boson-boson, ... -
Quasiparticle spinors in light-matter interactions: generalized Jaynes-Cummings and antiJaynes-Cummings models
(Research gate, 2020)Seeking a clear understanding of the physical nature of quasiparticle excitations formed in the JaynesCummings and antiJaynes-Cummings interaction mechanisms in the quantum Rabi model, we have introduced appropriate composite ... -
The Question of Elitism, Medium and Audience in African Literature: Examples from Kiswahili Short Story
(Academia.edu, 2014)Since the Makerere Conference of 1962, the question of what is ‘African Literature’ has remained unresolved. To a large extent a great number of scholars led by Ngugi reduced the whole question to that of language. This ... -
Quiet Time Correlation Between Geomagnetic Field Variations and the Dynamics of the East African Equatorial Ionosphere
(Science Publishing Group, 2017)The equatorial ionosphere is highly dynamic and consequently poses serious threats to communication and navigation systems. As a result, proper understanding of ionospheric dynamics is important. The present paper presents ... -
Quiet Time Geomagnetic Field Variations in the Equatorial East African Region During the Inclining Phase of Solar Cycle 24
(Science Publishing Group, 2014)In the present paper, geomagnetic field data obtained from magnetometer measurements at two ground based stations have been used to study solar activity dependence of the solar quiet variations. The study has focused on ... -
Rabi oscillations, entanglement and teleportation in the anti-Jaynes-Cummings model
(Cornell University, 2021)This paper provides a scheme for generating maximally entangled qubit states in the anti-JaynesCummings interaction mechanism, so called entangled anti-polariton qubit states. We demonstrate that in an initial vacuum-field, ... -
Rabi oscillations, entanglement and teleportation in the anti-Jaynes-Cummings model
(Cornell University, 2021)This paper provides a scheme for generating maximally entangled qubit states in the anti-JaynesCummings interaction mechanism, so called entangled anti-polariton qubit states. We demonstrate that in an initial vacuum-field, ... -
Revisiting non-degenerate parametric down-conversion
(Springer-Verlag, 2008)he quantum dynamics of a two-mode non-resonant parametric down-conversion process is studied by recasting the time evolution equations for the basic operators in an equivalent spin equation form with simpler exact solutions ... -
Rheological Properties of Blends of Isotactic Polystyrene–Isotactic Poly(para-methylstyrene) Films Derived from a Comparative Dewetting Study
(American Chemical Society, 2020)We examined changes in rheological properties of nonequilibrated spin-coated thin films of isotactic polystyrene (iPS) and isotactic poly(para-methylstyrene) and blends thereof by dewetting experiments. For 200 nm thick ... -
Robust Arduino controlled spin coater using a novel and simple gravity chuck design
(Elsevier, 2023-06)Spin coaters offer an invaluable method of thin film fabrication. Various implementations, both proprietary and open-source exist, offering vacuum and gravity samples chucks. These implementations vary in their reliability, ... -
Role of bismuth and substrate temperature on the optical properties of some flash evaporated se100-x bix glassy system
(University of Nairobi, Kenya, 2015)Chalcogenide glasses are very important in the modern technology especially selenium-based. These glasses are sensitive to electromagnetic radiation useful in the infrared optics. The study investigated the effect of ... -
Role of oxygen concentrations on structural and optical properties of RF magnetron sputtered ZnO thin films
(Springer US, 2019)We report an investigation on the efect of oxygen fow rate on the structural and optical properties of zinc oxide thin flms prepared by RF magnetron sputtering. The structural measurements were carried using grazing ... -
SCINDA-GPS derived TEC depletions and amplitude scintillations over Kisumu, Kenya during selected quiet and storm days of 2013 and 2014
(International Journal of Advanced Astronomy, 2020)Total Electron Content (TEC) depletion and amplitude scintillation (S4) can be derived from, SCINDA-GPS receivers situated in various parts of the equatorial region. In this paper we present results of characterization ... -
Shell structure of the SU (N) generator spectrum: interpretation as spin angular momentum operators
(Research gate, 2020)We have established that SU(N) symmetry group generators occur in a spectrum with a quantum structure composed of N − 1 configuration shells each containing a definite number of symmetric and antisymmetric pairs of ... -
Similarity Transformation Analysis of Heat and Mass Transfer Effects on Steady Buoyancy Induced MHD Free Convection Flow Past an Inclined Surface
(2017)The present work is devoted to the problem of a steady two di- mensional hydromagnetic convective ow of a viscous, incompressible electrically conducting uid past an inclined semi-in nite plate in the presence of ... -
Solutions of second-order partial differential equations in two independent variables using method of characteristics
(nternational Journal of Engineering and Mathematical Sciences, 2013-06-01)In this paper we have classified second order linear PDEs into three types, hyperbolic, parabolic and elliptic. Hyperbolic equations have two distinct families of (real) characteristic curves, parabolic equations have a ... -
Some new features of photon statistics in a fully quantized parametric amplification process
(Scientific Research Publishing, 2014)An exact quantum treatment reveals that signal and idler photon number operators are not wellbehaved dynamical operators for studying photon statistics in parametric amplification/downconversion processes. Contrary to ... -
: Spray Pyrolysis Technique (SPT) was used to deposit thin films (TFs) of cadmium stannate, doped with iron (Fe) for the first time. The precursor solutions that were used wereprepared at a concentration of 0.1M, doped with Feand then sprayed onto the pre-heated glass slides immediately at deposition temperatures of 350 ± 7°C, 400 ± 7°C and 450 ± 7°C. The optical properties of the deposited Fe-doped TFs were studied in the wavelength range of 300-1100nm. The X-Ray diffraction (XRD) studies showed that the TFs were orthorhombic with growth orientation along the (2 0 0) direction. Film thickness of 85 ± 10 nm was obtained. It was found out that anincrease in the deposition temperature increased transmittance and band gap, but decreased absorption coefficient, extinction coefficient and refractive index, which was attributed to the improvement in crystallinity of the deposited TFs. Doping reduced transmittance and band gap, but increased refractive index, absorption coefficient and extinction coefficient, which was attributed to the increase in free carriers. KEYWORDS:cadmium stannate, deposition temperature, iron-doped, optical properties of cadmium stannate
(Elsevier, 2020)The elastic properties of the orthorhombic cadmium stannate (Cd2SnO4) were investigated using density functional theory, applying both energy-strain relationship (which is found in the literature) and stress-strain ...