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C. Tannous

Publications and source records attributed to C. Tannous.

At least 19 recordsLinked to original sources
arXiv2021

Information theory based Electron Paramagnetic Resonance dating

Chronometric dating is becoming increasingly important in areas such as the Origin and evolution of Life on Earth and other planets, Origin and evolution of the Earth and the Solar System... Electron Spin Resonance (ESR) dating is based on exploiting effects of contamination by chemicals or ionizing radiation, on ancient matter through its absorption spectrum and lineshape. Interpreting absorption spectra as probability density functions (pdf), we use the notion of Information Theory (IT) distance allowing us to position the measured lineshape with respect to standard limiting pdf's (Lorentzian and Gaussian). This paves the way to perform dating when several interaction patterns between unpaired spins are present in geologic, planetary, meteorite or asteroid matter namely classical-dipolar (for ancient times) and quantum-exchange-coupled (for recent times). In addition, accurate bounds to age are provided by IT from the evaluation of distances with respect to the Lorentz and Gauss distributions. Dating arbitrary periods of times~\cite{Anderson} and exploiting IT to introduce rigorous and accurate date values might have interesting far reaching implications not only in Geophysics, Geochronology~\cite{Bahain}, Planetary Science but also in Mineralogy, Archaeology, Biology, Anthropology~\cite{Aitken}, Paleoanthropology~\cite{Taylor,Richter}...

physics.data-an↗
arXiv2017

Optimization of Quantum Key Distribution Protocols

Quantum Key Distribution is a practically implementable information-theoretic secure method for transmitting keys to remote partners performing quantum communication. After examining various protocols from the simplest such as QC and BB84 we move on to describe BBM92, DPSK, SARG04 and finally MDI from the largest possible communication distance and highest secret key bitrate. We discuss how any protocol can be optimized by reviewing the various steps and underlying assumptions proper to every protocol with the corresponding consequence in each case.

quant-ph↗
arXiv2017

Optimization of Measurement Device Independent Scarani-Acìn-Ribordy-Gisin protocol

The measurement device independent (MDI) Quantum Key Distribution (QKD) is a practically implementable method for transmitting secret keys between respective partners performing quantum communication. SARG04 (Scarani-Acìn-Ribordy-Gisin 2004) is a protocol tailored to struggle against photon number splitting (PNS) attacks by eavesdroppers and its MDI-QKD version is reviewed and optimized from secret key bitrate versus communication distance point of view. We consider the effect of several important factors such as error correction function, dark counting parameter and quantum efficiency in order to achieve the largest key bitrate versus longest communication distance.

quant-ph↗
arXiv2017

Symmetry and Piezoelectricity: Evaluation of $α$-Quartz coefficients

Piezoelectric coefficients of $α$-Quartz are derived from symmetry arguments based on Neumann's Principle with three different methods: Fumi, Landau-Lifshitz and Royer-Dieulesaint. While Fumi method is tedious and Landau-Lifshitz requires additional physical principles to evaluate the piezoelectric coefficients, Royer-Dieulesaint is the most elegant and most efficient of the three techniques.

cond-mat.mtrl-sci↗
arXiv2016

Electronic control of magnonic and spintronic devices

Nanometric magnonic and spintronic devices need magnetic field control in addition to conventional electronic control. In this work we review ways to replace magnetic field control by an electronic one in order to circumvent appearance of stray magnetic fields or the difficulty of creating large magnetic fields over nanometric distances. Voltage control is compared to current control and corresponding devices are compared from their energetic efficiency point of view.

cond-mat.mtrl-sci↗
arXiv2016

A Multisection Broadband Impedance Transforming Branch-Line Hybrid

Measurements and design equations for a two section impedance transforming hybrid suitable for MMIC applications and a new method of synthesis for multisection branch-line hybrids are reported. The synthesis method allows the response to be specified either of Butterworth or Chebyshev type. Both symmetric (with equal input and output impedances) and non-symmetric (impedance transforming) designs are feasible. Starting from a given number of sections, type of response, and impedance transformation ratio and for a specified midband coupling, power division ratio, isolation or directivity ripple bandwidth, the set of constants needed for the evaluation of the reflection coefficient response is first calculated. The latter is used to define a driving point impedance of the circuit, synthesize it and obtain the branch line immittances with the use of the concept of double length unit elements (DLUE). The experimental results obtained with microstrip hybrids constructed to test the validity of the brute force optimization and the synthesized designs show very close agreement with the computed responses.

physics.comp-ph↗
arXiv2016

Classical noise, Quantum noise and Secure communication

Secure communication based on message encryption might be performed by combining the message with controlled noise (called pseudo-noise) as performed in Spread-Spectrum communication used presently in Wi-Fi and Smartphone Telecommunication systems. Quantum communication based on entanglement is another route for securing communications as demonstrated by several important experiments described in this work. The central role played by the photon in unifying the description of Classical and Quantum noise as major ingredients of secure communication systems is highlighted and described on the basis of the classical and quantum fluctuation dissipation theorems.

quant-ph↗
arXiv2015

The Karlqvist approximation revisited

The Karlqvist approximation signaling the historical beginning of magnetic recording head theory is reviewed and compared to various approaches progressing from Green, Fourier, Conformal mapping that obeys the Sommerfeld edge condition at angular points and leads to exact results.

physics.class-ph↗
arXiv2013

Light production metrics of radiation sources

Light production by a radiation source is evaluated and reviewed as an important concept of physics from the Black-Body point of view. The mechanical equivalent of the lumen, the unit of perceived light, is explained and evaluated using radiation physics arguments. The existence of an upper limit of luminous efficacy is illustrated for various sources and implications are highlighted.

quant-ph↗
arXiv2013

Angular Preisach analysis of Hysteresis loops and FMR lineshapes of ferromagnetic nanowire arrays

Preisach analysis is applied to the study of hysteresis loops measured for different angles between the applied magnetic field and the common axis of ferromagnetic Nickel nanowire arrays. When extended to Ferromagnetic Resonance (FMR) lineshapes, with same set of parameters extracted from the corresponding hysteresis loops, Preisach analysis shows that a different distribution of interactions or coercivities ought to be used in order to explain experimental results. Inspecting the behavior of hysteresis loops and FMR linewidth versus field angle, we infer that angular dependence might be exploited in angle sensing devices that could compete with Anisotropic (AMR) or Giant Magnetoresistive (GMR) based devices.

cond-mat.mtrl-sci↗
arXiv2013

Temperature dependent anisotropy and elastic effects in ferromagnetic nanowire arrays

Temperature dependent Ferromagnetic Resonance measurements performed as a function of diameter on Nickel nanowire arrays reveal several interesting features in these systems. With diameter decrease from 100 nm to 15 nm, a transition induced by surface anisotropy increase is observed at 50 nm in easy axis orientation from parallel to perpendicular with respect to individual nanowire geometric axis. Analysis of resonance field $H_{res}$ temperature variation (between liquid Helium and room temperature) reveals underlying strong magneto-elastic effects in small and large diameter nanowire arrays with potential applications in recording and spintronics.

cond-mat.mtrl-sci↗
arXiv2013

Exact solutions of the Boeder differential equation for macromolecular orientations in a flowing liquid

The Boeder differential equation is solved in this work over a wide range of $α$, yielding the probability density functions (PDF), that describe the average orientations of rod-like macromolecules in a flowing liquid. The quantity $α$ is the ratio of the hydrodynamic shear rate to the rotational diffusion coefficient. It characterises the coupling of the motion of the macromolecules in the hydrodynamic flow to their thermal diffusion. Previous analytical work is limited to approximate solutions for small values of $α$. Special analytical as well as numerical methods are developed in the present work in order to calculate accurately the PDF for a range of $α$ covering several orders of magnitude, $10^{-6} \le α\le 10^{8}$. The mathematical nature of the differential equation is revealed as a singular perturbation problem when $α$ becomes large. Scaling results are obtained over the differential equation for $α\ge 10^{3}$. Monte Carlo Brownian simulations are also constructed and shown to agree with the numerical solutions of the differential equation in the bulk of the flowing liquid, for an extensive range of $α$. This confirms the robustness of the developed analytical and numerical methods.

physics.chem-ph↗
arXiv2010

Geometric signature of reversal modes in ferromagnetic nanowires

Magnetic nanowires are a good platform to study fundamental processes in Magnetism and have many attractive applications in recording such as perpendicular storage and in spintronics such as non-volatile magnetic memory devices (MRAM) and magnetic logic devices. In this work, nanowires are used to study magnetization reversal processes through a novel geometric approach. Reversal modes imprint a definite signature on a parametric curve representing the locus of the critical switching field. We show how the different modes affect the geometry of this curve depending on the nature of the anisotropy (uniaxial or cubic anisotropy), demagnetization and exchange effects. The samples we use are electrochemically grown Nickel and Cobalt nanowires.

physics.comp-ph↗
arXiv2010

Marching toward the eigenvalues: The Canonical Function Method and the Schrödinger equation

The Canonical Function Method (CFM) is a powerful accurate and fast method that solves the Schrödinger equation for the eigenvalues directly without having to evaluate the eigenfunctions. Its versatility allows to solve several types of problems and in this work it is applied to the solution of several 1D potential problems, the 3D Hydrogen atom and the Morse potential.

quant-ph↗
arXiv2009

Orientation control of rodlike objects by flow

Suspensions of rodlike objects in a liquid are encountered in many areas of science and technology and the need to orientate them is extremely important to enhance or inhibit certain chemical reactions between them, other chemicals or with the walls of vessels holding the flowing suspension. Orientation control is feasible by altering velocity and nature of the liquid, its flow and the geometry of the channel containing the flow. In this work we consider the simplest possibility of orientation control with flow in two dimensions on the basis of the orientation distribution of rodlike objects. The simple differential equation satisfied by the orientation probability density function is derived and its solution discussed. In addition, we show how birefringence and dichroism ("Maxwell effect") of the suspension provide a direct experimental test of orientation control.

physics.flu-dyn↗
arXiv2008

Orientation control by flow: Exact results and Langevin simulations

Rod shaped objects suspended in a flowing liquid might be orientated by the velocity, nature of the liquid, the flow and the geometry of the channel containing the flow. Orientation settings might enhance or inhibit certain chemical reactions between the objects, other chemicals or with the walls of vessels holding the flowing suspension. The probability density function (PDF) describing the orientations of rod shaped objects in a flowing liquid satisfies a Fokker-Planck equation whose solution is obtained analytically as well as numerically from Langevin simulations for different flow parameters. The analytical and numerical methods developed in the present work enable us to calculate accurately the PDF for a range of the Peclet number $α$ covering several orders of magnitude, $10^{-4} \le α\le 10^{8}$. We apply these results to the experimental determination of dichroism and birefringence of the suspension as a function of $α$.

physics.data-an↗
arXiv2008

The Stoner-Wohlfarth model of Ferromagnetism: Static properties

Recent advances in high-density magnetic storage and spin electronics are based on the use of magnetic materials along with conventional microelectronic materials (metals, insulators and semiconductors). The unit information (bit) is stored as a magnetization state in some ferromagnetic ma rial (FM) and controlled with an external field altering the magnetization state. As device size is shrinking steadily toward the nanometer and the need to incr se its bandwidth prevails, racing toward higher frequencies is getting even more cha enging. In magnetic systems, denser storage leads to finer magnetic grains and small size leads to single magnetic domain physics. The Stoner-Wohlfarth model is the simplest model that describes adequately the physics of fine magnetic grains containing single domains and where magnetization state changes by rotation or switching (abrupt reversal). The SW model is reviewed and discussed with its consequences and potential app cations in the physics of magnetism and spin electronics.

physics.class-ph↗