Quark Orbital Angular Momentum
Directory of Open Access Journals (Sweden)
Burkardt Matthias
2015-01-01
Full Text Available Definitions of orbital angular momentum based on Wigner distributions are used as a framework to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar. We find that the difference between these two definitions can be interpreted as the change in the quark orbital angular momentum as it leaves the target in a DIS experiment. The mechanism responsible for that change is similar to the mechanism that causes transverse single-spin asymmetries in semi-inclusive deep-inelastic scattering.
Orbital angular momentum: a personal memoir
Allen, L.
2017-02-01
A definitive statement of the model used to describe orbital angular momentum is essentially now available. Its early history, and the interaction of those who played key roles in its development over 20 years ago in its development, is outlined in this Memoir. This article is part of the themed issue 'Optical orbital angular momentum'.
Accelerated rotation with orbital angular momentum modes
CSIR Research Space (South Africa)
Schulze, C
2015-01-01
Full Text Available ) Accelerated rotation with orbital angular momentum modes Christian Schulze,1 Filippus S. Roux,2 Angela Dudley,2 Ronald Rop,3 Michael Duparre´,1 and Andrew Forbes2,4,* 1Institute of Applied Optics, Friedrich Schiller University, Fro¨belstieg 1, 07743 Jena... from the transverse acceleration discussed before. We tailor our “twisted light” (fields carrying orbital angular momentum) to have a nonlinear phase variation with azimuthal angle, which we show is the building block for angular accelerating light...
A quantum memory for orbital angular momentum photonic qubits
Nicolas, A.; Veissier, L.; Giner, L.; Giacobino, E.; Maxein, D.; Laurat, J.
2014-03-01
Among the optical degrees of freedom, the orbital angular momentum of light provides unique properties, including mechanical torque action, which has applications for light manipulation, enhanced sensitivity in imaging techniques and potential high-density information coding for optical communication systems. Recent years have also seen a tremendous interest in exploiting orbital angular momentum at the single-photon level in quantum information technologies. In pursuing this endeavour, we demonstrate here the implementation of a quantum memory for quantum bits encoded in this optical degree of freedom. We generate various qubits with computer-controlled holograms, store and retrieve them on demand using a dynamic electromagnetically induced transparency protocol. We further analyse the retrieved states by quantum tomography and thereby demonstrate fidelities exceeding the classical benchmark, confirming the quantum functioning of our storage process. Our results provide an essential capability for future networks exploring the promises of orbital angular momentum of photons for quantum information applications.
Optical communication beyond orbital angular momentum
Trichili, Abderrahmen; Rosales-Guzm?n, Carmelo; Dudley, Angela; Ndagano, Bienvenu; Ben Salem, Amine; Zghal, Mourad; Forbes, Andrew
2016-01-01
Mode division multiplexing (MDM) is mooted as a technology to address future bandwidth issues, and has been successfully demonstrated in free space using spatial modes with orbital angular momentum (OAM). To further increase the data transmission rate, more degrees of freedom are required to form a densely packed mode space. Here we move beyond OAM and demonstrate multiplexing and demultiplexing using both the radial and azimuthal degrees of freedom. We achieve this with a holographic approac...
Sorting and quantifying orbital angular momentum of laser beams
CSIR Research Space (South Africa)
Schulze, C
2013-10-01
Full Text Available We present a novel tool for sorting the orbital angular momentum and to determine the orbital angular momentum density of laser beams, which is based on the use of correlation filters....
Orbital angular momentum exchange in parametric down conversion
Huguenin, J. A. O.; Martinelli, M.; Caetano, D. P.; Coutinho Dos Santos, B.; Almeida, M. P.; Souto Ribeiro, P. H.; Nussenzveig, P.; Khoury, A. Z.
2006-05-01
Orbital angular momentum exchange, both in cavity free stimulated parametric down conversion and in an optical parametric oscillator, is studied. In both cases, the conditions for parametric amplification are discussed in terms of the orbital angular momentum exchange between the interacting fields. It is shown that in cavity free parametric down conversion, parametric amplification is conditioned to conserve orbital angular momentum. However, for parametric oscillation, cavity and anisotropy effects play a crucial role in the orbital angular momentum exchange between the interacting fields.
Optical communication beyond orbital angular momentum
CSIR Research Space (South Africa)
Trichili, A
2016-06-01
Full Text Available . 3CSIR National Laser Centre, PO Box 395, Pretoria 0001, South Africa. 4Institut Mines-Télécom/Télécom SudParis, 9 rue Charles Fourier, 91011 Evry, France. Correspondence and requests for materials should be addressed to C.R.-G. (email: carmelo..., Y. et al. Free-space optical communications using orbital-angular-momentum multiplexing combined with mimo-based spatial multiplexing. Opt. Lett. 40, 4210–4213 (2015). 19. Zhao, N., Li, X., Li, G. & Kahn, J. M. Capacity limits of spatially...
Optical communication beyond orbital angular momentum
Trichili, Abderrahmen; Rosales-Guzmán, Carmelo; Dudley, Angela; Ndagano, Bienvenu; Ben Salem, Amine; Zghal, Mourad; Forbes, Andrew
2016-06-01
Mode division multiplexing (MDM) is mooted as a technology to address future bandwidth issues, and has been successfully demonstrated in free space using spatial modes with orbital angular momentum (OAM). To further increase the data transmission rate, more degrees of freedom are required to form a densely packed mode space. Here we move beyond OAM and demonstrate multiplexing and demultiplexing using both the radial and azimuthal degrees of freedom. We achieve this with a holographic approach that allows over 100 modes to be encoded on a single hologram, across a wide wavelength range, in a wavelength independent manner. Our results offer a new tool that will prove useful in realizing higher bit rates for next generation optical networks.
High orbital angular momentum harmonic generation
Vieira, J; Alves, E P; Fonseca, R A; Mendonça, J T; Bingham, R; Norreys, P; Silva, L O
2016-01-01
We identify and explore a high orbital angular momentum (OAM) harmonics generation and amplification mechanism that manipulates the OAM independently of any other laser property, by preserving the initial laser wavelength, through stimulated Raman backscattering in a plasma. The high OAM harmonics spectra can extend at least up to the limiting value imposed by the paraxial approximation. We show with theory and particle-in-cell simulations that the orders of the OAM harmonics can be tuned according to a selection rule that depends on the initial OAM of the interacting waves. We illustrate the high OAM harmonics generation in a plasma using several examples including the generation of prime OAM harmonics. The process can also be realised in any nonlinear optical Kerr media supporting three-wave interactions.
Orbital angular momentum filter of photon based on spin-orbital angular momentum coupling
Energy Technology Data Exchange (ETDEWEB)
Chen, Dong-Xu; Zhang, Pei, E-mail: zhangpei@mail.ustc.edu.cn; Liu, Rui-Feng; Li, Hong-Rong; Gao, Hong; Li, Fu-Li
2015-10-16
Highlights: • We propose a scheme that can filter the orbital angular momentum of photons. • Our scheme filters the specific mode with destroying the mode. • Our scheme can theoretically filter infinity modes. • The orientation of Dove lens and HWP decides which mode will output. - Abstract: Determination of the orbital angular momentum (OAM) of vortex beams has been hotly discussed. We propose a new type of method to determine the orbital angular momentum of photons, filtering. We present an OAM filter scheme which consists of a cavity with a polarization-based Mach–Zehnder interferometer inside. Our scheme can purify the specific OAM with unitary efficiency theoretically without the pre-knowledge of the OAM spectrum of the input light. We also implemented a proof-of-principle experiment to demonstrate the feasibility of our scheme by cascading three interferometers. Our method offers a new way to determine the OAM spectrum of a light and this method can also be exploited to prepare the eigenstate of vortex beams.
Optical communications beyond orbital angular momentum
Rosales-Guzmán, Carmelo; Trichili, Abderrahmen; Dudley, Angela; Ndagano, Bienvenu; Ben Salem, Amine; Zghal, Mourad; Forbes, Andrew
2016-09-01
Current optical communication technologies are predicted to face a bandwidth capacity limit in the near future. The nature of the limitation is fundamental rather than technological and is set by nonlinearities in optical fibers. One solution, suggested over 30 years ago, comprises the use of spatial modes of light as information carriers. Along this direction, light beams endowed with orbital angular momentum (OAM) have been demonstrated as potential information carriers in both, free space and fibres. However, recent studies suggest that purely OAM modes does not increase the bandwidth of optical communication systems. In fact, in all work to date, only the azimuthal component of transverse spatial modes has been used. Crucially, all transverse spatial modes require two degrees of freedom to be described; in the context of Laguerre-Gaussian (LGp`) beams these are azimuthal (l) and radial (p), the former responsible for OAM. Here, we demonstrate a technique where both degrees of freedom of LG modes are used as information carrier over free space. We transfer images encoded using 100 spatial modes in three wavelengths as our basis, and employ a spatial demultiplexing scheme that detects all 100 modes simultaneously. Our scheme is a hybrid of MIMO and SMM, and serves as a proof-of-principle demonstration. The cross-talk between the modes is small and independent of whether OAM modes are used or not.
Accelerated rotation with orbital angular momentum modes
CSIR Research Space (South Africa)
Schulze, C
2015-04-01
Full Text Available . As the angular acceleration takes place in a bounded space, the azimuthal degree of freedom, such fields accelerate periodically as they propagate. Notably, the amount of angular acceleration is not limited by paraxial considerations, may be tailored for large...
Orbital angular momentum in optical fibers
Bozinovic, Nenad
Internet data traffic capacity is rapidly reaching limits imposed by nonlinear effects of single mode fibers currently used in optical communications. Having almost exhausted available degrees of freedom to orthogonally multiplex data in optical fibers, researchers are now exploring the possibility of using the spatial dimension of fibers, via multicore and multimode fibers, to address the forthcoming capacity crunch. While multicore fibers require complex manufacturing, conventional multi-mode fibers suffer from mode coupling, caused by random perturbations in fibers and modal (de)multiplexers. Methods that have been developed to address the problem of mode coupling so far, have been dependent on computationally intensive digital signal processing algorithms using adaptive optics feedback or complex multiple-input multiple-output algorithms. Here we study the possibility of using the orbital angular momentum (OAM), or helicity, of light, as a means of increasing capacity of future optical fiber communication links. We first introduce a class of specialty fibers designed to minimize mode coupling and show their potential for OAM mode generation in fibers using numerical analysis. We then experimentally confirm the existence of OAM states in these fibers using methods based on fiber gratings and spatial light modulators. In order to quantify the purity of created OAM states, we developed two methods based on mode-image analysis, showing purity of OAM states to be 90% after 1km in these fibers. Finally, in order to demonstrate data transmission using OAM states, we developed a 4-mode multiplexing and demultiplexing systems based on free-space optics and spatial light modulators. Using simple coherent detection methods, we successfully transmit data at 400Gbit/s using four OAM modes at a single wavelength, over 1.1 km of fiber. Furthermore, we achieve data transmission at 1.6Tbit/s using 10 wavelengths and two OAM modes. Our study indicates that OAM light can exist
The decay of orbital angular momentum entanglement in atmospheric turbulence
CSIR Research Space (South Africa)
Roux, FS
2013-07-01
Full Text Available Salam International Centre for Theoretical Physics, Trieste, Italy, 8-12 July 2013 The decay of orbital angular momentum entanglement in atmospheric turbulence Roux FS CSIR, National Laser Centre, Pretoria, 0001 Corresponding email: FSroux...
Superpositions of light fields carrying orbital angular momentum
CSIR Research Space (South Africa)
Dudley, Angela L
2012-01-01
Full Text Available The work presented in this thesis is centred on the generation of superimposed optical fields which each carry orbital angular momentum (OAM) and the development of OAM measurement techniques. Optical fields which carry OAM have found applications...
Continuous Variable Entanglement and Squeezing of Orbital Angular Momentum States
DEFF Research Database (Denmark)
Lassen, Mikael Østergaard; Leuchs, Gerd; Andersen, Ulrik Lund
2009-01-01
We report the first experimental characterization of the first-order continuous variable orbital angular momentum states. Using a spatially nondegenerate optical parametric oscillator (OPO) we produce quadrature entanglement between the two first-order Laguerre-Gauss modes. The family of orbital...... angular momentum modes is mapped on an orbital Poincaré sphere, where the mode's position on the sphere is spanned by the three orbital parameters. Using a nondegenerate OPO we produce squeezing of these parameters, and as an illustration, we reconstruct the “cigar-shaped” uncertainty volume...
Origins and demonstrations of electrons with orbital angular momentum
McMorran, Benjamin J.; Agrawal, Amit; Ercius, Peter A.; Grillo, Vincenzo; Herzing, Andrew A.; Harvey, Tyler R.; Linck, Martin; Pierce, Jordan S.
2017-02-01
The surprising message of Allen et al. (Allen et al. 1992 Phys. Rev. A 45, 8185 (doi:10.1103/PhysRevA.45.8185)) was that photons could possess orbital angular momentum in free space, which subsequently launched advancements in optical manipulation, microscopy, quantum optics, communications, many more fields. It has recently been shown that this result also applies to quantum mechanical wave functions describing massive particles (matter waves). This article discusses how electron wave functions can be imprinted with quantized phase vortices in analogous ways to twisted light, demonstrating that charged particles with non-zero rest mass can possess orbital angular momentum in free space. With Allen et al. as a bridge, connections are made between this recent work in electron vortex wave functions and much earlier works, extending a 175 year old tradition in matter wave vortices. This article is part of the themed issue 'Optical orbital angular momentum'.
Spin-to-orbital angular momentum conversion in dielectric metasurfaces
Devlin, Robert Charles; Wintz, Daniel; Oscurato, Stefano Luigi; Zhu, Alexander Yutong; Khorasaninejad, Mohammadreza; Oh, Jaewon; Maddalena, Pasqualino; Capasso, Federico
2016-01-01
Spin-to-orbital-angular-momentum conversion has attracted considerable interest as a tool to create exotic light beams, leading to the emergence of novel devices that implement this function. These converters exploit the geometrical phase to create helical beams of handedness determined by the chirality of the incident light. This property is finding important applications in quantum optics thanks to the demonstration of liquid crystal spin-to-orbital angular momentum converters (SOC) known as q-plates. Here we demonstrate high-efficiency SOCs in the visible based on dielectric metasurfaces that generate vortex beams with high and even fractional topological charge and show for the first time the simultaneous generation of collinear helical beams with different and arbitrary orbital angular momentum. We foresee that this versatile method of creating vortex beams, which circumvents the limitations of q-plates, will significant impact microscopy and vector beam shaping.
Implementing quantum walks using orbital angular momentum of classical light.
Goyal, Sandeep K; Roux, Filippus S; Forbes, Andrew; Konrad, Thomas
2013-06-28
We present an implementation scheme for a quantum walk in the orbital angular momentum space of a laser beam. The scheme makes use of a ring interferometer, containing a quarter-wave plate and a q plate. This setup enables one to perform an arbitrary number of quantum walk steps. In addition, the classical nature of the implementation scheme makes it possible to observe the quantum walk evolution in real time. We use nonquantum entanglement of the laser beam's polarization with its orbital angular momentum to implement the quantum walk.
Zhang, Zijing; Qiao, Tianyuan; Ma, Kun; Cen, Longzhu; Zhang, Jiandong; Wang, Feng; Zhao, Yuan
2016-08-15
Photon orbital angular momentum has led to many novel insights and applications in quantum measurement. Photon orbital angular momentum can increase the resolution and sensitivity of angular rotation measurement. However, quantum measurement strategy can further surpass this limit and improve the resolution of angular rotation measurement. This Letter proposes and demonstrates a parity measurement method in angular rotation measurement scheme for the first time. Parity measurement can make the resolution superior to the limit of the existing method. The sensitivity can be improved with higher orbital angular momentum photons. Moreover, this Letter gives a detailed discussion of the change of resolution and sensitivity in the presence of photon loss.
Angular dependence of spin-orbit spin-transfer torques
Lee, Ki-Seung
2015-04-06
In ferromagnet/heavy-metal bilayers, an in-plane current gives rise to spin-orbit spin-transfer torque, which is usually decomposed into fieldlike and dampinglike torques. For two-dimensional free-electron and tight-binding models with Rashba spin-orbit coupling, the fieldlike torque acquires nontrivial dependence on the magnetization direction when the Rashba spin-orbit coupling becomes comparable to the exchange interaction. This nontrivial angular dependence of the fieldlike torque is related to the Fermi surface distortion, determined by the ratio of the Rashba spin-orbit coupling to the exchange interaction. On the other hand, the dampinglike torque acquires nontrivial angular dependence when the Rashba spin-orbit coupling is comparable to or stronger than the exchange interaction. It is related to the combined effects of the Fermi surface distortion and the Fermi sea contribution. The angular dependence is consistent with experimental observations and can be important to understand magnetization dynamics induced by spin-orbit spin-transfer torques.
Implementing quantum walks using orbital angular momentum of classical light
CSIR Research Space (South Africa)
Goyal, SK
2013-06-01
Full Text Available We present an implementation scheme for a quantum walk in the orbital angular momentum space of a laser beam. The scheme makes use of a ring interferometer, containing a quarter-wave plate and a q plate. This setup enables one to perform...
Dichroism for Orbital Angular Momentum using Stimulated Parametric Down Conversion
Lowney, Joseph; Faccio, Daniele; Wright, Ewan M
2014-01-01
We theoretically analyze stimulated parametric down conversion as a means to produce dichroism based on the orbital angular momentum (OAM) of an incident signal field. The nonlinear interaction is shown to provide differential gain between signal states of differing OAM, the peak gain occurring at half the OAM of the pump field.
Offset tolerance of an orbital angular momentum optical communication system with angular deflection
Yin, Xiao-li; Sang, Hong-qing; Cui, Xiao-Zhou; Chang, Huan; Li, Li; Wu, Guo-hua
2017-06-01
This work studied the offset tolerance (OT) with a particular focus on the angular deflection of an orbital angular momentum (OAM) system in free space. We derived an analytical expression of the OT for an angular-deflected Laguerre-Gaussian (LG) beam via Fourier series (FS) expansion and determined the upper bound of the OT for OAM-multiplexed systems. Next, we analyzed the effects of the beam waist, transmitted distance and OAM state number on the OT numerically. The calculation results indicate that the OT of the deflected beam is inversely proportional to the square root of the OAM number and approximately reciprocal to the propagation distance. Finally, we calculated the bit-error rate (BER) and aggregated capacity of multiplexed systems with different sets of channels. The results confirmed that the estimated upper bound is reasonable, especially for larger mode spacings. This work can provide guidance for the design and optimization of angular-deflected OAM-multiplexed communication systems.
Vorticity Measurement using LG Laser Beams with Orbital Angular Momentum
Kooochesfahani, Manoochehr; Pouya, Shahram; Safaripour, Alireza; Ryabtsev, Anton; Dantus, Marcos
2016-11-01
We present direct measurement of vorticity in a fluid flow based on angular velocity measurement of microparticles contained in the fluid. The method uses Laguerre-Gaussian (LG) laser beams that possess orbital angular momentum (OAM), a spatial (azimuthal) modulation of the beam phase front, and takes advantage of the rotational Doppler shift from microparticles intersecting the beam focus. Results are shown for the flow field of solid body rotation, where the flow vorticity is known precisely. This work was supported by AFOSR Award Number FA9550-14-1-0312.
Tunable orbital angular momentum in high-harmonic generation.
Gauthier, D; Ribič, P Rebernik; Adhikary, G; Camper, A; Chappuis, C; Cucini, R; DiMauro, L F; Dovillaire, G; Frassetto, F; Géneaux, R; Miotti, P; Poletto, L; Ressel, B; Spezzani, C; Stupar, M; Ruchon, T; De Ninno, G
2017-04-05
Optical vortices are currently one of the most intensively studied topics in optics. These light beams, which carry orbital angular momentum (OAM), have been successfully utilized in the visible and infrared in a wide variety of applications. Moving to shorter wavelengths may open up completely new research directions in the areas of optical physics and material characterization. Here, we report on the generation of extreme-ultraviolet optical vortices with femtosecond duration carrying a controllable amount of OAM. From a basic physics viewpoint, our results help to resolve key questions such as the conservation of angular momentum in highly nonlinear light-matter interactions, and the disentanglement and independent control of the intrinsic and extrinsic components of the photon's angular momentum at short-wavelengths. The methods developed here will allow testing some of the recently proposed concepts such as OAM-induced dichroism, magnetic switching in organic molecules and violation of dipolar selection rules in atoms.
Electronic orbital angular momentum and magnetism of graphene
Luo, Ji
2013-01-01
Orbital angular momentum (OAM) of graphene electrons in a perpendicular magnetic field is calculated and corresponding magnetic moment is used to investigate the magnetism of perfect graphene. Variation in magnetization demonstrates its decrease with carrier-doping, plateaus in a large field, and de Haas-van Alphen oscillation. Regulation of magnetism by a parallel electric field is presented. The OAM originates from atomic-scale electronic motion in graphene lattice, and vector hopping inter...
Unveiling the orbital angular momentum and acceleration of electron beams.
Shiloh, Roy; Tsur, Yuval; Remez, Roei; Lereah, Yossi; Malomed, Boris A; Shvedov, Vladlen; Hnatovsky, Cyril; Krolikowski, Wieslaw; Arie, Ady
2015-03-06
New forms of electron beams have been intensively investigated recently, including vortex beams carrying orbital angular momentum, as well as Airy beams propagating along a parabolic trajectory. Their traits may be harnessed for applications in materials science, electron microscopy, and interferometry, and so it is important to measure their properties with ease. Here, we show how one may immediately quantify these beams' parameters without need for additional fabrication or nonstandard microscopic tools. Our experimental results are backed by numerical simulations and analytic derivation.
Holographic tool kit for optical communication beyond orbital angular momentum
Trichili, Abderrahmen; Rosales-Guzmán, Carmelo; Dudley, Angela; Ndagano, Bienvenu; Salem, Amine Ben; Zghal, Mourad; Forbes, Andrew
2016-01-01
Mode division multiplexing (MDM) is mooted as a technology to address future bandwidth issues, and has been successfully demonstrated in free space using spatial modes with orbital angular momentum (OAM). To further increase the data transmission rate, more degrees of freedom are required to form a densely packed mode space. Here we move beyond OAM and demonstrate multiplexing and demultiplexing using both the radial and azimuthal degrees of freedom. We achieve this with a holographic approac...
Multiple orbital angular momentum generated by dielectric hybrid phase element
Wang, Xuewen; Kuchmizhak, Aleksandr; Hu, Dejiao; Li, Xiangping
2017-09-01
Vortex beam carrying multiple orbital angular momentum provides a new degree of freedom to manipulate light leading to the various exciting applications as trapping, quantum optics, information multiplexing, etc. Helical wavefront can be generated either via the geometric or the dynamic phase arising from a space-variant birefringence (q-plate) or from phase accumulation through propagation (spiral-phase-plate), respectively. Using fast direct laser writing technique we fabricate and characterize novel hybrid q-plate generating vortex beam simultaneously carrying two different high-order topological charges, which arise from the spin-orbital conversion and the azimuthal height variation of the recorded structures. We approve the versatile concept to generate multiple-OAM vortex beams combining the spin-orbital interaction and the phase accumulation in a single micro-scale device, a hybrid dielectric phase plate.
Position, spin, and orbital angular momentum of a relativistic electron
Bliokh, Konstantin Y.; Dennis, Mark R.; Nori, Franco
2017-08-01
Motivated by recent interest in relativistic electron vortex states, we revisit the spin and orbital angular momentum properties of Dirac electrons. These are uniquely determined by the choice of the position operator for a relativistic electron. We consider two main approaches discussed in the literature: (i) the projection of operators onto the positive-energy subspace, which removes the Zitterbewegung effects and correctly describes spin-orbit interaction effects, and (ii) the use of Newton-Wigner-Foldy-Wouthuysen operators based on the inverse Foldy-Wouthuysen transformation. We argue that the first approach [previously described in application to Dirac vortex beams in K. Y. Bliokh et al., Phys. Rev. Lett. 107, 174802 (2011), 10.1103/PhysRevLett.107.174802] has a more natural physical interpretation, including spin-orbit interactions and a nonsingular zero-mass limit, than the second one [S. M. Barnett, Phys. Rev. Lett. 118, 114802 (2017), 10.1103/PhysRevLett.118.114802].
Generation of electromagnetic waves with arbitrary orbital angular momentum modes.
Cheng, Li; Hong, Wei; Hao, Zhang-Cheng
2014-04-28
Recently, much attention has been focused on beams carrying orbital angular momentum (OAM) for radio communication. Here we experimentally demonstrate a planar-spiral phase plate (planar-SPP) for generating arbitrary mixed OAM beams. This proposed planar-SPP uses the concept of transmit array antenna having a perforated substrate to control the outputting phase for generating beams carrying OAM with arbitrary modes. As demonstrations, three planar-SPPs with a single OAM mode and two mixed OAM modes around 94 GHz have been investigated with design and experiments in this paper, respectively. The typical experimental intensity and phase patterns show that the proposed method of generating OAM beams really works.
Squeezing of X waves with orbital angular momentum
Ornigotti, Marco; Szameit, Alexander; Conti, Claudio
2016-01-01
Multi-level quantum protocols may potentially supersede standard quantum optical polarization-encoded protocols in terms of amount of information transmission and security. However, for free space telecomunications, we do not have tools for limiting loss due to diffraction and perturbations, as for example turbulence in air. Here we study propagation invariant quantum X-waves with angular momentum; this representation expresses the electromagnetic field as a quantum gas of weakly interacting bosons. The resulting spatio-temporal quantized light pulses are not subject to diffraction and dispersion, and are intrinsically resilient to disturbances in propagation. We show that spontaneous down-conversion generates squeezed X-waves useful for quantum protocols. Surprisingly the orbital angural momentum affects the squeezing angle, and we predict the existence of a characteristic axicon aperture for maximal squeezing. There results may boost the applications in free space of quantum optical transmission and multi-l...
Measuring the orbital angular momentum spectrum of an electron beam
Grillo, Vincenzo; Tavabi, Amir H.; Venturi, Federico; Larocque, Hugo; Balboni, Roberto; Gazzadi, Gian Carlo; Frabboni, Stefano; Lu, Peng-Han; Mafakheri, Erfan; Bouchard, Frédéric; Dunin-Borkowski, Rafal E.; Boyd, Robert W.; Lavery, Martin P. J.; Padgett, Miles J.; Karimi, Ebrahim
2017-01-01
Electron waves that carry orbital angular momentum (OAM) are characterized by a quantized and unbounded magnetic dipole moment parallel to their propagation direction. When interacting with magnetic materials, the wavefunctions of such electrons are inherently modified. Such variations therefore motivate the need to analyse electron wavefunctions, especially their wavefronts, to obtain information regarding the material's structure. Here, we propose, design and demonstrate the performance of a device based on nanoscale holograms for measuring an electron's OAM components by spatially separating them. We sort pure and superposed OAM states of electrons with OAM values of between −10 and 10. We employ the device to analyse the OAM spectrum of electrons that have been affected by a micron-scale magnetic dipole, thus establishing that our sorter can be an instrument for nanoscale magnetic spectroscopy. PMID:28537248
Compact and high-resolution optical orbital angular momentum sorter
Directory of Open Access Journals (Sweden)
Chenhao Wan
2017-03-01
Full Text Available A compact and high-resolution optical orbital angular momentum (OAM sorter is proposed and demonstrated. The sorter comprises a quadratic fan-out mapper and a dual-phase corrector positioned in the pupil plane and the Fourier plane, respectively. The optical system is greatly simplified compared to previous demonstrations of OAM sorting, and the performance in resolution and efficiency is maintained. A folded configuration is set up using a single reflective spatial light modulator (SLM to demonstrate the validity of the scheme. The two phase elements are implemented on the left and right halves of the SLM and connected by a right-angle prism. Experimental results demonstrate the high resolution of the compact OAM sorter, and the current limit in efficiency can be overcome by replacing with transmissive SLMs and removing the beam splitters. This novel scheme paves the way for the miniaturization and integration of high-resolution OAM sorters.
Encoding Orbital Angular Momentum of Lights in Magnets
Fujita, Hiroyuki
2016-01-01
Breaking the diffraction limit and focusing laser beams to nanometre-scale are becoming possible with the help of recent developments in plasmonics. This allows us to explore nano-scale physics induced by laser beams with complex spatial profiles like optical vortex, or laser carrying orbital angular momentum (OAM). On the basis of numerical calculations using Landau-Lifshitz-Gilbert equation, here we propose two OAM-dependent phenomena induced by optical vortex, spin waves with multipolar and spiral wave fronts, and ultrafast generation of various kinds of topological defects in chiral magnets. We show that by using Tera Hz optical vortex, we can generate skyrmionic defects with timescale orders of magnitude shorter than by other known schemes.
Nucleon spin decomposition and orbital angular momentum in the nucleon
Wakamatsu, Masashi
2014-09-01
To get a complete decomposition of nucleon spin is a fundamentally important homework of QCD. In fact, if our researches end up without accomplishing this task, a tremendous efforts since the 1st discovery of the nucleon spin crisis would end in the air. We now have a general agreement that there are at least two physically inequivalent gauge-invariant decompositions of the nucleon. In these two decompositions, the intrinsic spin parts of quarks and gluons are just common. What discriminate these two decompositions are the orbital angular momentum (OAM) parts. The OAMs of quarks and gluons appearing in the first decomposition are the so-called ``mechanical'' OAMs, while those appearing in the second decomposition are the generalized (gauge-invariant) ``canonical'' ones. By this reason, these decompositions are broadly called the ``mechanical'' and ``canonical'' decompositions of the nucleon spin. Still, there remains several issues, which have not reached a complete consensus among the experts. (See the latest recent). In the present talk, I will mainly concentrate on the practically most important issue, i.e. which decomposition is more favorable from the observational viewpoint. There are two often-claimed advantages of canonical decomposition. First, each piece of this decomposition satisfies the SU(2) commutation relation or angular momentum algebra. Second, the canonical OAM rather than the mechanical OAM is compatible with free partonic picture of constituent orbital motion. In the present talk, I will show that both these claims are not necessarily true, and push forward a viewpoint that the ``mechanical'' decomposition is more physical in that it has more direct connection with observables. I also emphasize that the nucleon spin decomposition accessed by the lattice QCD analyses is the ``mechanical'' decomposition not the ``canonical'' one. The recent lattice QCD studies of the nucleon spin decomposition are also briefly overviewed.
High-capacity millimetre-wave communications with orbital angular momentum multiplexing
National Research Council Canada - National Science Library
Yan, Yan; Xie, Guodong; Lavery, Martin P J; Huang, Hao; Ahmed, Nisar; Bao, Changjing; Ren, Yongxiong; Cao, Yinwen; Li, Long; Zhao, Zhe; Molisch, Andreas F; Tur, Moshe; Padgett, Miles J; Willner, Alan E
2014-01-01
.... Such orbital angular momentum based multiplexing can potentially increase the system capacity and spectral efficiency of millimetre-wave wireless communication links with a single aperture pair...
Partonic Orbital Angular Momentum and Lorentz Invariance Relations
Rajan, Abha; Liuti, Simonetta; Engelhardt, Michael
2017-09-01
We show that Generalized Transverse Momentum Distributions (GTMDs) and twist three Generalized Parton Distributions (GPDs) can be connected through Lorentz Invariant Relations. The equations of motion along with the Lorentz Invariance Relations allow one to explicitly write the separate contributions to twist three GPDs from leading twist GPDs, a quark gluon quark correlation term and, in some cases, a mass term. In particular, the GTMD F14 or the correlation of an unpolarized quark in a longitudinally polarized proton, is known to describe the quarks. Orbital Angular Momentum (OAM). In a separate approach, the twist three GPD Ẽ2 T tilde was also be shown to connect to OAM. We show that these two definitions are connected by a Lorentz Invariance Relation. A similar relation is found for the GTMD G11 which describes quark spin orbit correlations in the proton can be connected to the twist three GPDs E2T ' and H 2T ' . These relations show how twist three GPDs through an implicit quark gluon interaction reproduce the effects of intrinsic transverse momentum in the GTMDs.
Pluto Moons exhibit Orbital Angular Momentum Quantization per Mass
Directory of Open Access Journals (Sweden)
Potter F.
2012-10-01
Full Text Available The Pluto satellite system of the planet plus five moons is shown to obey the quan- tum celestial mechanics (QCM angular momentum per mass quantization condition predicted for any gravitationally bound system.
Extreme Ultraviolet Fractional Orbital Angular Momentum Beams from High Harmonic Generation
Turpin, Alex; Rego, Laura; Picón, Antonio; San Román, Julio; Hernández-García, Carlos
2017-03-01
We investigate theoretically the generation of extreme-ultraviolet (EUV) beams carrying fractional orbital angular momentum. To this end, we drive high-order harmonic generation with infrared conical refraction (CR) beams. We show that the high-order harmonic beams emitted in the EUV/soft x-ray regime preserve the characteristic signatures of the driving beam, namely ringlike transverse intensity profile and CR-like polarization distribution. As a result, through orbital and spin angular momentum conservation, harmonic beams are emitted with fractional orbital angular momentum, and they can be synthesized into structured attosecond helical beams -or “structured attosecond light springs”- with rotating linear polarization along the azimuth. Our proposal overcomes the state of the art limitations for the generation of light beams far from the visible domain carrying non-integer orbital angular momentum and could be applied in fields such as diffraction imaging, EUV lithography, particle trapping, and super-resolution imaging.
CSIR Research Space (South Africa)
Mafu, M
2013-09-01
Full Text Available We present an experimental study of higher-dimensional quantum key distribution protocols based on mutually unbiased bases, implemented by means of photons carrying orbital angular momentum. We perform (d + 1) mutually unbiased measurements in a...
CSIR Research Space (South Africa)
Roux, FS
2011-01-01
Full Text Available Orbital angular momentum (OAM) entangled bi-photons are a resource for the higher dimensional implementation of quantum cryptography, which allows secure communication over various channels. In the case where free-space is used as communication...
Extreme Ultraviolet Fractional Orbital Angular Momentum Beams from High Harmonic Generation.
Turpin, Alex; Rego, Laura; Picón, Antonio; San Román, Julio; Hernández-García, Carlos
2017-03-10
We investigate theoretically the generation of extreme-ultraviolet (EUV) beams carrying fractional orbital angular momentum. To this end, we drive high-order harmonic generation with infrared conical refraction (CR) beams. We show that the high-order harmonic beams emitted in the EUV/soft x-ray regime preserve the characteristic signatures of the driving beam, namely ringlike transverse intensity profile and CR-like polarization distribution. As a result, through orbital and spin angular momentum conservation, harmonic beams are emitted with fractional orbital angular momentum, and they can be synthesized into structured attosecond helical beams -or "structured attosecond light springs"- with rotating linear polarization along the azimuth. Our proposal overcomes the state of the art limitations for the generation of light beams far from the visible domain carrying non-integer orbital angular momentum and could be applied in fields such as diffraction imaging, EUV lithography, particle trapping, and super-resolution imaging.
Song, Xinbing; Sun, Yifan; Li, Pengyun; Qin, Hongwei; Zhang, Xiangdong
2015-01-01
We perform Bell’s measurement for the non-separable correlation between polarization and orbital angular momentum from the same classical vortex beam. The violation of Bell’s inequality for such a non-separable classical correlation has been demonstrated experimentally. Based on the classical vortex beam and non-quantum entanglement between the polarization and the orbital angular momentum, the Hadamard gates and conditional phase gates have been designed. Furthermore, a quantum Fourier transform has been implemented experimentally. PMID:26369424
Song, Xinbing; Sun, Yifan; Li, Pengyun; Qin, Hongwei; Zhang, Xiangdong
2015-09-15
We perform Bell's measurement for the non-separable correlation between polarization and orbital angular momentum from the same classical vortex beam. The violation of Bell's inequality for such a non-separable classical correlation has been demonstrated experimentally. Based on the classical vortex beam and non-quantum entanglement between the polarization and the orbital angular momentum, the Hadamard gates and conditional phase gates have been designed. Furthermore, a quantum Fourier transform has been implemented experimentally.
Spin-to-orbital angular momentum conversion and spin-polarization filtering in electron beams.
Karimi, Ebrahim; Marrucci, Lorenzo; Grillo, Vincenzo; Santamato, Enrico
2012-01-27
We propose the design of a space-variant Wien filter for electron beams that induces a spin half-turn and converts the corresponding spin angular momentum variation into orbital angular momentum of the beam itself by exploiting a geometrical phase arising in the spin manipulation. When applied to a spatially coherent input spin-polarized electron beam, such a device can generate an electron vortex beam, carrying orbital angular momentum. When applied to an unpolarized input beam, the proposed device, in combination with a suitable diffraction element, can act as a very effective spin-polarization filter. The same approach can also be applied to neutron or atom beams.
Wu, H W; Wang, F; Dong, Y Q; Shu, F Z; Zhang, K; Peng, R W; Xiong, X; Wang, Mu
2015-12-14
In this work, we theoretically study the cavity modes with transverse orbital angular momentum in metamaterial ring based on transformation optics. The metamaterial ring is designed to transform the straight trajectory of light into the circulating one by enlarging the azimuthal angle, effectively presenting the modes with transverse orbital angular momentum. The simulation results confirm the theoretical predictions, which state that the transverse orbital angular momentum of the mode not only depends on the frequency of the incident light, but also depends on the transformation scale of the azimuthal angle. Because energy dissipation inevitably reduces the field amplitude of the modes, the confined electromagnetic energy and the quality factor of the modes inside the ring are also studied in order to evaluate the stability of those cavity modes. The results show that the metamaterial ring can effectively confine light with a high quality factor and maintain steady modes with the orbital angular momentum, even if the dimension of the ring is much smaller than the wavelength of the incident light. This technique for exploiting the modes with optical transverse orbital angular momentum may provides a unique platform for applications related to micromanipulation.
Engelhardt, M.
2017-05-01
Given a Wigner distribution simultaneously characterizing quark transverse positions and momenta in a proton, one can directly evaluate their cross product, i.e., quark orbital angular momentum. The aforementioned distribution can be obtained by generalizing the proton matrix elements of quark bilocal operators which define transverse momentum-dependent parton distributions (TMDs); the transverse momentum information is supplemented with transverse position information by introducing an additional nonzero momentum transfer. A gauge connection between the quarks must be specified in the quark bilocal operators; the staple-shaped gauge link path used in TMD calculations yields the Jaffe-Manohar definition of orbital angular momentum, whereas a straight path yields the Ji definition. An exploratory lattice calculation, performed at the pion mass mπ=518 MeV , is presented which quasicontinuously interpolates between the two definitions and demonstrates that their difference can be clearly resolved. The resulting Ji orbital angular momentum is confronted with traditional evaluations based on Ji's sum rule. Jaffe-Manohar orbital angular momentum is enhanced in magnitude compared to its Ji counterpart.
Quantum storage of orbital angular momentum entanglement in cold atomic ensembles
Shi, Bao-Sen; Ding, Dong-Sheng; Zhang, Wei
2018-02-01
Electromagnetic waves have both spin momentum and orbital angular momentum (OAM). Light carrying OAM has broad applications in micro-particle manipulation, high-precision optical metrology, and potential high-capacity optical communications. In the concept of quantum information, a photon encoded with information in its OAM degree of freedom enables quantum networks to carry much more information and increase their channel capacity greatly compared with those of current technology because of the inherent infinite dimensions for OAM. Quantum memories are indispensable to construct quantum networks. Storing OAM states has attracted considerable attention recently, and many important advances in this direction have been achieved during the past few years. Here we review recent experimental realizations of quantum memories using OAM states, including OAM qubits and qutrits at true single photon level, OAM states entangled in a two-dimensional or a high-dimensional space, hyperentanglement and hybrid entanglement consisting of OAM and other degree of freedom in a physical system. We believe that all achievements described here are very helpful to study quantum information encoded in a high-dimensional space.
Acoustic Virtual Vortices with Tunable Orbital Angular Momentum for Trapping of Mie Particles
Marzo, Asier; Caleap, Mihai; Drinkwater, Bruce W.
2018-01-01
Acoustic vortices can transfer angular momentum and trap particles. Here, we show that particles trapped in airborne acoustic vortices orbit at high speeds, leading to dynamic instability and ejection. We demonstrate stable trapping inside acoustic vortices by generating sequences of short-pulsed vortices of equal helicity but opposite chirality. This produces a "virtual vortex" with an orbital angular momentum that can be tuned independently of the trapping force. We use this method to adjust the rotational speed of particles inside a vortex beam and, for the first time, create three-dimensional acoustics traps for particles of wavelength order (i.e., Mie particles).
Toda, Y.; Moriya, A.; Yamane, K.; Morita, R.; Shigematsu, K.; Awaji, Y.
2017-09-01
The single orbital angular momentum mode emission from a commercially available broad-area vertical cavity surface emitting laser (VCSEL) is realized with an optical feedback technique using a spatial light modulator, where a computer generated hologram (CGH) is optimized by taking into account the mode properties of the external cavity VCSEL. The flexibility with which the chirality of the orbital angular momentum mode can be selected is also demonstrated simply by changing the chirality of the CGH. The technique is very simple and easily applicable to other VCSELs without processing.
Refractive elements for the measurement of the orbital angular momentum of a single photon.
Lavery, Martin P J; Robertson, David J; Berkhout, Gregorius C G; Love, Gordon D; Padgett, Miles J; Courtial, Johannes
2012-01-30
We have developed a mode transformer comprising two custom refractive optical elements which convert orbital angular momentum states into transverse momentum states. This transformation allows for an efficient measurement of the orbital angular momentum content of an input light beam. We characterise the channel capacity of the system for 50 input modes, giving a maximum value of 3.46 bits per photon. Using an electron multiplying CCD (EMCCD) camera with a laser source attenuated such that on average there is less than one photon present within the system per measurement period, we demonstrate that the elements are efficient for the use in single photon experiments.
Orbital-angular-momentum mixing in type-II second-harmonic generation
Pereira, Leonardo J.; Buono, Wagner T.; Tasca, Daniel S.; Dechoum, Kaled; Khoury, Antonio Z.
2017-11-01
We investigate the nonlinear mixing of orbital angular momentum in type-II second-harmonic generation with arbitrary topological charges imprinted on two orthogonally polarized beams. Starting from the basic nonlinear equations for the interacting fields, we derive the selection rules determining the set of paraxial modes taking part in the interaction. Conservation of orbital angular momentum naturally appears as the topological charge selection rule. However, a less intuitive rule applies to the radial orders when modes carrying opposite helicities are combined in the nonlinear crystal, an intriguing feature confirmed by experimental measurements.
Secular precessing compact binary dynamics, spin and orbital angular momentum flip-flops
Tápai, Márton; Keresztes, Zoltán; Gergely, László Árpád
2016-01-01
We derive the conservative secular evolution of precessing compact binaries to second post-Newtonian order accuracy, with leading-order spin-orbit, spin-spin and mass quadrupole-monopole contributions included. The emerging closed system of first-order differential equations evolves the pairs of polar and azimuthal angles of the spin and orbital angular momentum vectors together with the periastron angle. In contrast with the instantaneous dynamics, the secular dynamics is autonomous. This se...
MEMS-based wavelength and orbital angular momentum demultiplexer for on-chip applications
DEFF Research Database (Denmark)
Lyubopytov, Vladimir; Porfirev, Alexey P.; Gurbatov, Stanislav O.
2017-01-01
Summary form only given. We demonstrate a new tunable MEMS-based WDM&OAM Fabry-Pérot filter for simultaneous wavelength (WDM) and Orbital Angular Momentum (OAM) (de)multiplexing. The WDM&OAM filter is suitable for dense on-chip integration and dedicated for the next generation of optical...
Propagation of orbital angular momentum carrying beams through a perturbing medium
CSIR Research Space (South Africa)
Chaibi, A
2013-09-01
Full Text Available The orbital angular momentum of light has been suggested as a means of information transfer over free-space, yet the detected optical vortex is known to be sensitive to perturbation. Such effects have been studied theoretically, in particular...
The proton electromagnetic form factor F2 and quark orbital angular ...
Indian Academy of Sciences (India)
Protein; electromagnetic form factors; perturbative QCD; quark orbital angular momentum. PACS Nos 13.40.Gp; 12.38.Bx; 13.88.+e; 14.20.Dh. The recent JLAB measurement of the proton electromagnetic form factor ratio [1–3] shows the puzzling .... of integration regions, given the complexity of the problem. Elsewhere [7] ...
The measurable distinction between the spin and orbital angular momenta of electromagnetic radiation
Directory of Open Access Journals (Sweden)
James H. Crichton
2000-07-01
Full Text Available We show how the angular momentum of electromagnetic radiation may be decomposed into spin and orbital parts, of which the spin part is measurable in terms of Stokes parameters, thereby providing an unambiguous, gauge-invariant, distinction between the two parts.
Encoding mutually unbiased bases in orbital angular momentum for quantum key distribution
CSIR Research Space (South Africa)
Dudley, Angela L
2013-07-01
Full Text Available We encode mutually unbiased bases (MUBs) using the higher-dimensional orbital angular momentum (OAM) degree of freedom associated with optical fields. We illustrate how these states are encoded with the use of a spatial light modulator (SLM). We...
Orbital angular momentum correlations with a phase-flipped Gaussian mode pump beam
CSIR Research Space (South Africa)
Romero, J
2012-08-01
Full Text Available We report orbital angular momentum (OAM) and angle correlations between signal and idler photons observed when the nonlinear crystal used in spontaneous parametric down-conversion is illuminated by a non-fundamental Gaussian pump beam. We introduce...
Energy Technology Data Exchange (ETDEWEB)
Bouchard, Frédéric; De Leon, Israel; Schulz, Sebastian A.; Upham, Jeremy; Karimi, Ebrahim, E-mail: ekarimi@uottawa.ca [Department of Physics, University of Ottawa, 25 Templeton, Ottawa, Ontario K1N 6N5 Canada (Canada); Boyd, Robert W. [Department of Physics, University of Ottawa, 25 Templeton, Ottawa, Ontario K1N 6N5 Canada (Canada); Institute of Optics, University of Rochester, Rochester, New York 14627 (United States)
2014-09-08
Orbital angular momentum associated with the helical phase-front of optical beams provides an unbounded “space” for both classical and quantum communications. Among the different approaches to generate and manipulate orbital angular momentum states of light, coupling between spin and orbital angular momentum allows a faster manipulation of orbital angular momentum states because it depends on manipulating the polarisation state of light, which is simpler and generally faster than manipulating conventional orbital angular momentum generators. In this work, we design and fabricate an ultra-thin spin-to-orbital angular momentum converter, based on plasmonic nano-antennas and operating in the visible wavelength range that is capable of converting spin to an arbitrary value of orbital angular momentum ℓ. The nano-antennas are arranged in an array with a well-defined geometry in the transverse plane of the beam, possessing a specific integer or half-integer topological charge q. When a circularly polarised light beam traverses this metasurface, the output beam polarisation switches handedness and the orbital angular momentum changes in value by ℓ=±2qℏ per photon. We experimentally demonstrate ℓ values ranging from ±1 to ±25 with conversion efficiencies of 8.6% ± 0.4%. Our ultra-thin devices are integratable and thus suitable for applications in quantum communications, quantum computations, and nano-scale sensing.
Directory of Open Access Journals (Sweden)
Potter F.
2013-07-01
Full Text Available Quantum celestial mechanics (QCM predicts that all orbiting bodies in gravitationally bound systems exhibit the quantization of orbital angular momentum per unit mass. I show that the 15 known multi-planet systems with four or more planets obey this QCM prediction. This angular momentum constraint could be the explanation for their orbital stability for billions of years, suggesting that viable models of the formation and evolution of gravitational systems must include QCM.
Lu, Xiancong; Wu, Ziwen; Zhang, Wuhong; Chen, Lixiang
2014-05-01
The law of angular momentum conservation is naturally linked to the rotational symmetry of the involved system. Here we demonstrate theoretically how to break the rotational symmetry of a uniaxial crystal via the electro-optic Pockels effect. By numerical method based on asymptotic expansion, we discover the 3D structure of polarization singularities in terms of C lines and L surfaces embedded in the emerging light. We visualize the controllable dynamics evolution of polarization singularities when undergoing the Pockels effect, which behaves just like the binary fission of a prokaryotic cell, i.e., the splitting of C points and fission of L lines are animated in analogy with the cleavage of nucleus and division of cytoplasm. We reveal the connection of polarization singularity dynamics with the accompanying generation of orbital angular momentum sidebands. It is unexpected that although the total angular momentum of light is not conserved, the total topological index of C points is conserved.
Geometric phase and fractional orbital-angular-momentum states in electron vortex beams
Bandyopadhyay, Pratul; Basu, Banasri; Chowdhury, Debashree
2017-01-01
We study here fractional orbital-angular-momentum (OAM) states in electron vortex beams (EVBs) from the perspective of the geometric phase. We consider the skyrmionic model of an electron, where it is depicted as a scalar electron orbiting around the vortex line, which gives rise to the spin degrees of freedom. The geometric phase acquired by the scalar electron orbiting the vortex line induces the spin-orbit interaction. This leads to the fractional OAM states when we have a nonquantized monopole charge associated with the corresponding geometric phase. This involves a tilted vortex in EVBs. The monopole charge undergoes renormalization-group flow, which incorporates a length scale dependence making the fractional OAM states unstable upon propagation. It is pointed out that when EVBs move in an external magnetic field, the Gouy phase associated with the Laguerre-Gaussian modes modifies the geometric phase factor and a proper choice of the radial index helps to have a stable fractional OAM state.
The Geometric phase and fractional orbital angular momentum states in electron vortex beams
Bandyopadhyay, Pratul; Chowdhury, Debashree
2016-01-01
We study here fractional orbital angular momentum (OAM) states in electron vortex beams (EVB) from the perspective of geometric phase. We have considered the skyrmionic model of an electron, where it is depicted as a scalar electron orbiting around the vortex line, which gives rise to the spin degrees of freedom. The geometric phase acquired by the scalar electron orbiting around the vortex line induces the spin-orbit interaction, which leads to the fractional OAM states with non-quantized monopole charge associated with the corresponding geometric phase. This involves tilted vortex in EVBs. The monopole charge undergoes the renormalization group (RG) flow, which incorporates a length scale dependence making the fractional OAM states unstable upon propagation. It is pointed out that when EVBs move in an external magnetic field, the Gouy phase associated with the Laguerre-Gaussian modes modifies the geometric phase factor and a proper choice of the radial index helps to have a stable fractional OAM state.
Li, Nan; Chu, Xiuxiang; Zhang, Pengfei; Feng, Xiaoxing; Fan, ChengYu; Qiao, Chunhong
2018-01-01
A method which can be used to compensate for a distorted orbital angular momentum and wavefront of a beam in atmospheric turbulence, simultaneously, has been proposed. To confirm the validity of the method, an experimental setup for up-link propagation of a vortex beam in a turbulent atmosphere has been simulated. Simulation results show that both of the distorted orbital angular momentum and the distorted wavefront of a beam due to turbulence can be compensated by an adaptive optics system with the help of a cooperative beacon at satellite. However, when the number of the lenslet of wavefront sensor (WFS) and the actuators of the deform mirror (DM) is small, satisfactory results cannot be obtained.
Fickler, Robert; Lapkiewicz, Radek; Huber, Marcus; Lavery, Martin P J; Padgett, Miles J; Zeilinger, Anton
2014-07-30
Photonics has become a mature field of quantum information science, where integrated optical circuits offer a way to scale the complexity of the set-up as well as the dimensionality of the quantum state. On photonic chips, paths are the natural way to encode information. To distribute those high-dimensional quantum states over large distances, transverse spatial modes, like orbital angular momentum possessing Laguerre Gauss modes, are favourable as flying information carriers. Here we demonstrate a quantum interface between these two vibrant photonic fields. We create three-dimensional path entanglement between two photons in a nonlinear crystal and use a mode sorter as the quantum interface to transfer the entanglement to the orbital angular momentum degree of freedom. Thus our results show a flexible way to create high-dimensional spatial mode entanglement. Moreover, they pave the way to implement broad complex quantum networks where high-dimensionally entangled states could be distributed over distant photonic chips.
Controlling light's helicity at the source: orbital angular momentum states from lasers.
Forbes, Andrew
2017-02-28
Optical modes that carry orbital angular momentum (OAM) are routinely produced external to the laser cavity and have found a variety of applications, thus increasing the demand for integrated solutions for their production. Yet such modes are notoriously difficult to produce from lasers due to the strict symmetry requirements for their creation, together with the need to break the degeneracy in helicity. Here, we review the progress made since 1992 in producing such twisted light modes directly at the source, from gas to solid-state lasers, bulk to integrated on-chip solutions, through to generic devices for on-demand OAM in both scalar and vector forms.This article is part of the themed issue 'Optical orbital angular momentum'. © 2017 The Author(s).
On the Coupling of Photon Spin to Electron Orbital Angular Momentum
Fischer, Ulrich C; Fuchs, Harald; Salut, Roland; Lefier, Yannick; Grosjean, Thierry
2016-01-01
Partially gold coated 90 degree glass wedges and a semi - infinite slit in a thin film of gold ending in a conducting nano-junction serve as samples to investigate the transfer of photon spin to electron orbital angular momentum. These structures were specifically designed as samples where an incident beam of light is retroreflected. Since in the process of retroreflection the turning sense of a circularly polarized beam of light does not change and the direction of propagation is inverted, the photon spin is inverted. Due to conservation of angular momentum a transfer of photon spin to electron orbital angular momentum of conduction electrons occurs. In the structures a circular movement of electrons is blocked and therefore the transfered spin can be detected as a photovoltage due to an electromotive force which is induced by the transfer of angular momentum. Depending on the polarization of the incident beam, a maximum photovoltage of about 0,2 micro V was measured for both structures. The results are inte...
Phase-shift interference-based wavefront characterization for orbital angular momentum modes.
Huang, Hao; Ren, Yongxiong; Yan, Yan; Ahmed, Nisar; Yue, Yang; Bozovich, Amanda; Erkmen, Baris I; Birnbaum, Kevin; Dolinar, Sam; Tur, Moshe; Willner, Alan E
2013-07-01
Wavefront characterization for orbital angular momentum (OAM) modes is demonstrated using quadrature phase-shift interference. The phase fronts and intensity profiles of OAM(-2), OAM(-4), OAM(-6), and OAM(-8) are measured. Wavefront correlations between the experimental results and the pure Laguerre-Gaussian modes are calculated to evaluate the measurement. The measured results are in reasonable agreement with the anticipated results based on simulations.
Circular dichroism of cholesteric polymers and the orbital angular momentum of light
Löffler, W; Woerdman, J P
2011-01-01
We explore experimentally if the light's orbital angular momentum (OAM) interacts with chiral nematic polymer films. Specifically, we measure the circular dichroism of such a material using light beams with different OAM. We investigate the case of strongly focussed, non-paraxial light beams, where the spatial and polarization degrees of freedom are coupled. Within the experimental accuracy, we cannot find any influence of the OAM on the circular dichroism of the cholesteric polymer.
Walasik, Wiktor T.; Silahli, Salih Z.; Litchinitser, Natalia M.
2016-09-01
Colloidal metamaterials are a robust and flexible platform for engineering of optical nonlinearities and studies of light filamentation. To date, nonlinear propagation and modulation instability of Gaussian beams and optical vortices carrying orbital angular momentum were studied in such media. Here, we investigate the propagation of necklace beams and the conservation of the orbital angular momentum in colloidal media with saturable nonlinearity. We study various scenarios leading to generation of helical necklace beams or twisted beams, depending on the radius, power, and charge of the input vortex beam. Helical beams are build of two separate solitary beams with circular cross-sections that spiral around their center of mass as a result of the equilibrium between the attraction force of in-phase solitons and the centrifugal force associated with the rotational movement. A twisted beam is a single beam with an elliptical cross-section that rotates around it's own axis. We show that the orbital angular momentum is converted into the rotational motion at different rates for helical and twisted beams. While earlier studies reported that solitary beams are expelled form the initial vortex ring along straight trajectories tangent to the vortex ring, we show that depending on the charge and the power of the initial beam, these trajectories can diverge from the tangential direction and may be curvilinear. These results provide a detailed description of necklace beam dynamics in saturable nonlinear media and may be useful in studies of light filamentation in liquids and light propagation in highly scattering colloids and biological samples.
Twisted anisotropic fibers for robust orbital-angular-momentum-based information transmission
Barshak, E. V.; Alexeyev, C. N.; Lapin, B. P.; Yavorsky, M. A.
2015-03-01
We study the light propagation in the twisted anisotropic optical fibers endowed with torsional mechanical stress by obtaining the analytical solution of the vector wave equation. We show that at certain interplay between fiber parameters optical vortex beams of topological charge ℓ =0 ,±1 ,±2 ,... become the modes of the fibers in question. To explain the splitting of the optical vortex propagation constants we introduce the notions of orbital birefringence and optical Zeeman effect. Moreover, we unveil that induced by torsional stress circular birefringence makes the vortex beams with the well-defined orbital angular momentum robust against small perturbations characterized by both constant and spatially varying orientation of a director. We believe that such fibers can be successfully utilized for the long-range robust transmission of information encoded in the light's orbital degrees of freedom.
Effective field analysis using the full angular spin-orbit torque magnetometry dependence
Schulz, Tomek; Lee, Kyujoon; Krüger, Benjamin; Lo Conte, Roberto; Karnad, Gurucharan V.; Garcia, Karin; Vila, Laurent; Ocker, Berthold; Ravelosona, Dafiné; Kläui, Mathias
2017-06-01
Spin-orbit torques promise ultraefficient magnetization switching used for advanced devices based on emergent quasiparticles such as domain walls and skyrmions. Recently, the spin structure dynamics, materials, and systems with tailored spin-orbit torques are being developed. A method, which allows one to detect the acting torques in a given system as a function of the magnetization direction is the torque magnetometry method based on a higher harmonics analysis of the anomalous Hall effect. Here we show that the effective fields acting on magnetic domain walls that govern the efficiency of their dynamics require a sophisticated analysis taking into account the full angular dependence of the torques. Using a one-dimensional model, we compared the spin-orbit torque efficiencies by depinning measurements and spin torque magnetometry. We show that the effective fields can be accurately determined and we find good agreement. Thus, our method allows us now to rapidly screen materials and predict the resulting quasiparticle dynamics.
Variable Mixed Orbital Character in the Photoelectron Angular Distribution of NO_{2}
Laws, Benjamin A.; Cavanagh, Steven J.; Lewis, Brenton R.; Gibson, Stephen T.
2017-06-01
NO_{2} a key component of photochemical smog and an important species in the Earth's atmosphere, is an example of a molecule which exhibits significant mixed orbital character in the HOMO. In photoelectron experiments the geometric properties of the parent anion orbital are reflected in the photoelectron angular distribution (PAD), an area of research that has benefited largely from the ability of velocity-map imaging (VMI) to simultaneously record both the energetic and angular information, with 100% collection efficiency. Photoelectron spectra of NO_{2}^{-}, taken over a range of wavelengths (355nm-520nm) with the ANU's VMI spectrometer, reveal an anomalous jump in the anisotropy parameter near threshold. Consequently, the orbital behavior of NO_{2}^{-} appears to be quite different near threshold compared to detachment at higher photon energies. This surprising effect is due to the Wigner Threshold law, which causes p orbital character to dominate the photodetachment cross-section near threshold, before the mixed s/d orbital character becomes significant at higher electron kinetic energies. By extending recent work on binary character models to form a more general expression, the variable mixed orbital character of NO_{2}^{-} is able to be described. This study provides the first multi-wavelength NO_{2} anisotropy data, which is shown to be in decent agreement with much earlier zero-core model predictions of the anisotropy parameter. K. J. Reed, A. H. Zimmerman, H. C. Andersen, and J. I. Brauman, J. Chem. Phys. 64, 1368, (1976). doi:10.1063/1.432404 D. Khuseynov, C. C. Blackstone, L. M. Culberson, and A. Sanov, J. Chem. Phys. 141, 124312, (2014). doi:10.1063/1.4896241 W. B. Clodius, R. M. Stehman, and S. B. Woo, Phys. Rev. A. 28, 760, (1983). doi:10.1103/PhysRevA.28.760 Research supported by the Australian Research Council Discovery Project Grant DP160102585
On the role of quark orbital angular momentum in the proton spin
Directory of Open Access Journals (Sweden)
Zavada Petr
2015-01-01
Full Text Available We study the covariant version of the quark-parton model, in which the general rules of the angular momentum composition are accurately taken into account. We demonstrate how these rules affect the relativistic interplay between the quark spins and orbital angular momenta, which collectively contribute to the proton spin. The spin structure functions g1 and g2 corresponding to the many-quark state J = 1/2 are studied and it is shown they satisfy constraints and relations well compatible with the available experimental data including proton spin content Δ∑ ≲ 1/3. The suggested Lorentz invariant 3D approach for calculation of the structure functions is compared with the approach based on the conventional collinear parton model.
CSIR Research Space (South Africa)
Giovannini, D
2013-06-01
Full Text Available : QELS_Fundamental Science, San Jose, California United States, 9-14 June 2013 Reconstruction of High-Dimensional States Entangled in Orbital Angular Momentum Using Mutually Unbiased Measurements D. Giovannini1, ⇤, J. Romero1, 2, J. Leach3, A.... Dudley4, A. Forbes4, 5 and M. J. Padgett1 1 School of Physics and Astronomy, SUPA, University of Glasgow, Glasgow G12 8QQ, United Kingdom 2 Department of Physics, SUPA, University of Strathclyde, Glasgow G4 ONG, United Kingdom 3 School of Engineering...
Dynamic control of coherent orbital-angular-momentum beams in turbid environments
Morgan, K. S.; Miller, J. K.; Cochenour, B. M.; Johnson, E. G.
2016-05-01
This work examines the propagation properties of two superimposed coherent orbital angular momentum (OAM) modes for use in underwater systems as an alternative to amplitude modulation. An OAM mode of l=+2 is interfered with OAM mode l=-1 from a λ = 540 nm laser source. These OAM modes are superimposed using a Mach-Zehnder (MZ) interferometer combined with diffractive optical elements. By manipulating the optical path length of one of the MZ legs, the interference of these beams can be temporally controlled. The spatial profile is maintained in a turbid environment up through 4.9 attenuation lengths for both cases.
Modeling channel interference in an orbital angular momentum-multiplexed laser link
Anguita, Jaime A.; Neifeld, Mark A.; Vasic, Bane V.
2009-08-01
We study the effects of optical turbulence on the energy crosstalk among constituent orbital angular momentum (OAM) states in a vortex-based multi-channel laser communication link and determine channel interference in terms of turbulence strength and OAM state separation. We characterize the channel interference as a function of C2n and transmit OAM state, and propose probability models to predict the random fluctuations in the received signals for such architecture. Simulations indicate that turbulence-induced channel interference is mutually correlated across receive channels.
Wavelength-selective orbital-angular-momentum beam generation using MEMS tunable Fabry-Perot filter.
Paul, Sujoy; Lyubopytov, Vladimir S; Schumann, Martin F; Cesar, Julijan; Chipouline, Arkadi; Wegener, Martin; Küppers, Franko
2016-07-15
We demonstrate an on-chip device capable of wavelength-selective generation of vortex beams, which is realized by a spiral phase plate integrated onto a microelectromechanical system (MEMS) tunable filter. This vortex MEMS filter, being capable of functioning simultaneously in both wavelength and orbital-angular-momentum (OAM) domains at the 1550 nm wavelength regime, is considered as a compact, robust, and cost-effective solution for simultaneous OAM- and wavelength-division multiplexed optical communications. The experimental OAM spectra for azimuthal orders 1, 2, and 3 show an OAM state purity >92% across a wavelength range of more than 30 nm.
Tunable orbital angular momentum mode filter based on optical geometric transformation.
Huang, Hao; Ren, Yongxiong; Xie, Guodong; Yan, Yan; Yue, Yang; Ahmed, Nisar; Lavery, Martin P J; Padgett, Miles J; Dolinar, Sam; Tur, Moshe; Willner, Alan E
2014-03-15
We present a tunable mode filter for spatially multiplexed laser beams carrying orbital angular momentum (OAM). The filter comprises an optical geometric transformation-based OAM mode sorter and a spatial light modulator (SLM). The programmable SLM can selectively control the passing/blocking of each input OAM beam. We experimentally demonstrate tunable filtering of one or multiple OAM modes from four multiplexed input OAM modes with vortex charge of ℓ=-9, -4, +4, and +9. The measured output power suppression ratio of the propagated modes to the blocked modes exceeds 14.5 dB.
Underwater optical communications using orbital angular momentum-based spatial division multiplexing
Willner, Alan E.; Zhao, Zhe; Ren, Yongxiong; Li, Long; Xie, Guodong; Song, Haoqian; Liu, Cong; Zhang, Runzhou; Bao, Changjing; Pang, Kai
2018-02-01
In this paper, we review high-capacity underwater optical communications using orbital angular momentum (OAM)-based spatial division multiplexing. We discuss methods to generate and detect blue-green optical data-carrying OAM beams as well as various underwater effects, including attenuation, scattering, current, and thermal gradients on OAM beams. Attention is also given to the system performance of high-capacity underwater optical communication links using OAM-based space division multiplexing. The paper closes with a discussion of a digital signal processing (DSP) algorithm to mitigate the inter-mode crosstalk caused by thermal gradients.
Multi-gigabit/s underwater optical communication link using orbital angular momentum multiplexing.
Baghdady, Joshua; Miller, Keith; Morgan, Kaitlyn; Byrd, Matthew; Osler, Sean; Ragusa, Robert; Li, Wenzhe; Cochenour, Brandon M; Johnson, Eric G
2016-05-02
In this work we experimentally demonstrated an underwater wireless optical communications (UWOC) link over a 2.96 m distance with two 445-nm fiber-pigtailed laser diodes employing Orbital Angular Momentum (OAM) to allow for spatial multiplexing. Using an on-off keying, non-return-to-zero (OOK-NRZ) modulation scheme, a data rate of 3 Gbit/s was achieved in water with an attenuation coefficient of 0.4128 m-1 at an average bit error rate (BER) of 2.073 × 10-4, well beneath the forward error correction (FEC) threshold.
Quantum information with even and odd states of orbital angular momentum of light
Perumangatt, Chithrabhanu; Lal, Nijil; Anwar, Ali; Gangi Reddy, Salla; Singh, R. P.
2017-06-01
We address the possibility of using even/odd states of orbital angular momentum (OAM) of photons for the quantum information tasks. Single photon qubit states and two photon entangled states in even/odd basis of OAM are considered. We present a method for the tomography and general projective measurement in even/odd basis. With the general projective measurement, we show the Bell violation and quantum cryptography with Bell's inequality. We also describe hyper and hybrid entanglement of even/odd OAM states along with polarization, which can be applied in the implementation of quantum protocols like super dense coding.
CSIR Research Space (South Africa)
Hamadou Ibrahim, A
2011-08-01
Full Text Available University of Kwazulu-Natal, Private Bag X54001, 4000 Durban, South Africa ABSTRACT The orbital angular momentum (OAM) state of light can potentially be used to implement higher dimensional entangled systems for quantum communication. Unfortunately, optical fibers.... The phase fluctuation ?(x, y) on the phase screen is related to the refractive index fluctuation n?(x, y, z) of the medium through ?(x, y) = k0 ? ?z 0 n?(x, y, z)dz, (1) where k0 is the wave number. The common way of calculating the phase fluctuation...
Liu, Changming; Wei, Xuli; Niu, Liting; Wang, Kejia; Yang, Zhengang; Liu, Jinsong
2016-06-13
We present an efficient method to discriminate orbital angular momentum (OAM) of the terahertz (THz) vortex beam using a diffractive mode transformer. The mode transformer performs a log-polar coordinate transformation of the input THz vortex beam, which consists of two 3D-printed diffractive elements. A following lens separates each transformed OAM mode to a different lateral position in its focal plane. This method enables a simultaneous measurement over multiple OAM modes of the THz vortex beam. We experimentally demonstrate the measurement of seven individual OAM modes and two multiplexed OAM modes, which is in good agreement with simulations.
Control of optical orbital angular momentum by Vogel spiral arrays of metallic nanoparticles.
Lawrence, Nate; Trevino, Jacob; Dal Negro, Luca
2012-12-15
In this Letter, we experimentally demonstrate structured light carrying multiple values of orbital angular momentum (OAM) in the farfield scattering region of Vogel spiral arrays of metallic nanoparticles. Using Fourier-Hankel mode decomposition analysis and interferometric reconstruction of the complex amplitude of scattered waves, we show the ability to encode well-defined numerical sequences, determined by the aperiodic spiral geometry, into azimuthal OAM values, in excellent agreement with analytical scattering theory. The generation of azimuthal sequences of OAM values by light scattering from engineered aperiodic surfaces is relevant to a number of device applications for secure optical communication, classical cryptography, and quantum cryptography.
850-nm hybrid fiber/free-space optical communications using orbital angular momentum modes
DEFF Research Database (Denmark)
Jurado-Navas, Antonio; Tatarczak, Anna; Lu, Xiaofeng
2015-01-01
Light beams can carry orbital angular momentum (OAM) associated to the helicity of their phasefronts. These OAM modes can be employed to encode information onto a laser beam for transmitting not only in a fiber link but also in a free-space optical (FSO) one. Regarding this latter scenario, FSO c...... to the multimode fiber link. In addition, we report a better and more robust behavior of higher order OAM modes when the intermodal dispersion is dominant in the fiber after exceeding its maximum range of operation.......Light beams can carry orbital angular momentum (OAM) associated to the helicity of their phasefronts. These OAM modes can be employed to encode information onto a laser beam for transmitting not only in a fiber link but also in a free-space optical (FSO) one. Regarding this latter scenario, FSO...... modes can be seen as an efficient solution to increase the capacity and the security in the link. In this paper, we discuss an experimental demonstration of a proposal for next generation FSO communication system where a light beam carrying different OAM modes and affected by M turbulence is coupled...
Li, Guixin; Wu, Lin; Li, King F; Chen, Shumei; Schlickriede, Christian; Xu, Zhengji; Huang, Siya; Li, Wendi; Liu, Yanjun; Pun, Edwin Y B; Zentgraf, Thomas; Cheah, Kok W; Luo, Yu; Zhang, Shuang
2017-12-13
The spin and orbital angular momentum (SAM and OAM) of light is providing a new gateway toward high capacity and robust optical communications. While the generation of light with angular momentum is well studied in linear optics, its further integration into nonlinear optical devices will open new avenues for increasing the capacity of optical communications through additional information channels at new frequencies. However, it has been challenging to manipulate the both SAM and OAM of nonlinear signals in harmonic generation processes with conventional nonlinear materials. Here, we report the generation of spin-controlled OAM of light in harmonic generations by using ultrathin photonic metasurfaces. The spin manipulation of OAM mode of harmonic waves is experimentally verified by using second harmonic generation (SHG) from gold meta-atom with 3-fold rotational symmetry. By introducing nonlinear phase singularity into the metasurface devices, we successfully generate and measure the topological charges of spin-controlled OAM mode of SHG through an on-chip metasurface interferometer. The nonlinear photonic metasurface proposed in this work not only opens new avenues for manipulating the OAM of nonlinear optical signals but also benefits the understanding of the nonlinear spin-orbit interaction of light in nanoscale devices.
Quantum information with even and odd states of orbital angular momentum of light
Energy Technology Data Exchange (ETDEWEB)
Perumangatt, Chithrabhanu, E-mail: chithrabhanu@prl.res.in [Physical Research laboratory, Navarangpura, Ahmedabad, 380009 (India); Lal, Nijil [Physical Research laboratory, Navarangpura, Ahmedabad, 380009 (India); IIT Gandhinagar, Palaj, Ahmedabad, 382355 (India); Anwar, Ali [Physical Research laboratory, Navarangpura, Ahmedabad, 380009 (India); Gangi Reddy, Salla [University of Electro-communications, Chofu, Tokyo, 1828585 (Japan); Singh, R.P. [Physical Research laboratory, Navarangpura, Ahmedabad, 380009 (India)
2017-06-15
We address the possibility of using even/odd states of orbital angular momentum (OAM) of photons for the quantum information tasks. Single photon qubit states and two photon entangled states in even/odd basis of OAM are considered. We present a method for the tomography and general projective measurement in even/odd basis. With the general projective measurement, we show the Bell violation and quantum cryptography with Bell's inequality. We also describe hyper and hybrid entanglement of even/odd OAM states along with polarization, which can be applied in the implementation of quantum protocols like super dense coding. - Highlights: • We propose to use even and odd states of orbital angular momentum (OAM) of light for quantum information tasks. • We describe the OAM qubits and entangled states in even/odd basis and the corresponding projective operators. • We present a method for the tomography and the Bell's inequality violation for photons entangled in even/odd OAM states. • We also describe hyper and hybrid entanglement of even/odd OAM states along with polarization and their applications.
On the exchange of orbital angular momentum between twisted photons and atomic electrons
Davis, Basil S.; Kaplan, L.; McGuire, J. H.
2013-03-01
We obtain an expression for the matrix element for scattering of a twisted (Laguerre-Gaussian profile) photon from a hydrogen atom. We consider photons incoming with an orbital angular momentum (OAM) of ℓħ, carried by a factor of eiℓϕ not present in a plane-wave or pure Gaussian profile beam. The nature of the transfer of +2ℓ units of OAM from the photon to the azimuthal atomic quantum number of the atom is investigated. We obtain simple formulas for these OAM flip transitions for elastic forward scattering of twisted photons when the photon wavelength λ is large compared with the atomic target size a, and small compared with the Rayleigh range zR, which characterizes the collimation length of the twisted photon beam.
Excitation of Orbital Angular Momentum Resonances in Helically Twisted Photonic Crystal Fiber
Wong, G. K. L.; Kang, M. S.; Lee, H. W.; Biancalana, F.; Conti, C.; Weiss, T.; Russell, P. St. J.
2012-07-01
Spiral twisting offers additional opportunities for controlling the loss, dispersion, and polarization state of light in optical fibers with noncircular guiding cores. Here, we report an effect that appears in continuously twisted photonic crystal fiber. Guided by the helical lattice of hollow channels, cladding light is forced to follow a spiral path. This diverts a fraction of the axial momentum flow into the azimuthal direction, leading to the formation of discrete orbital angular momentum states at wavelengths that scale linearly with the twist rate. Core-guided light phase-matches topologically to these leaky states, causing a series of dips in the transmitted spectrum. Twisted photonic crystal fiber has potential applications in, for example, band-rejection filters and dispersion control.
Wigner functions for angle and orbital angular momentum. Operators and dynamics
Energy Technology Data Exchange (ETDEWEB)
Kastrup, Hans A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie
2017-02-15
Recently a paper on the construction of consistent Wigner functions for cylindrical phase spaces S{sup 1} x R, i.e. for the canonical pair angle and orbital angular momentum, was presented, main properties of those functions derived, discussed and their usefulness illustrated by examples. The present paper is a continuation which compares properties of the new Wigner functions for cylindrical phase spaces with those of the well-known Wigner functions on planar ones in more detail. Furthermore, the mutual (Weyl) correspondence between HIlbert space operators and their phase space functions is discussed. The * product formalism is shown to be completely implementable. In addition basic dynamical laws for Wigner and Moyal functions are derived as generalized Liouville and energy equations. They are very similar to those of the planar case, but also show characteristic differences.
WGM resonators for studying orbital angular momentum of a photon, and methods
Matsko, Andrey B. (Inventor); Savchenkov, Anatoliy A. (Inventor); Maleki, Lute (Inventor); Strekalov, Dmitry V. (Inventor)
2009-01-01
An optical system, device, and method that are capable of generating high-order Bessel beams and determining the orbital angular momentum of at least one of the photons of a Bessel beam are provided. The optical system and device include a tapered waveguide having an outer surface defined by a diameter that varies along a longitudinal axis of the waveguide from a first end to an opposing second end. The optical system and device include a resonator that is arranged in optical communication with the first end of the tapered waveguide such that an evanescent field emitted from (i) the waveguide can be coupled with the resonator, or (ii) the resonator can be coupled with the waveguide.
Bai, Zhengyang; Xu, Datang; Huang, Guoxiang
2017-01-23
We propose a scheme to realize the storage and retrieval of high-dimensional electromagnetic waves with orbital angular momentum (OAM) via plasmon-induced transparency (PIT) in a metamaterial, which consists of an array of meta-atoms constructed by a metallic structure loaded with two varactors. We show that due to PIT effect the system allows the existence of shape-preserving dark-mode plasmonic polaritons, which are mixture of electromagnetic-wave modes and dark oscillatory modes of the meta-atoms and may carry various OAMs. We demonstrate that the slowdown, storage and retrieval of multi-mode electromagnetic waves with OAMs can be achieved through the active manipulation of a control field. Our work raises the possibility for realizing PIT-based spatial multi-mode memory of electromagnetic waves and is promising for practical application of information processing with large capacity by using room-temperature metamaterials.
Tunable orbital angular momentum beams in the extreme ultraviolet/soft x-ray regimes
Turpin, Alex; Rego, Laura; San Román, Julio; Picón, Antonio; Plaja, Luis; Hernández-García, Carlos
2017-05-01
High-order harmonic generation (HHG) has been recently proven to produce harmonic vortices carrying orbital angular momentum (OAM) in the extreme-ultraviolet (XUV) region from the nonlinear up-conversion of infrared vortex beams. In this work we present two methods to control and extend the OAM content of the harmonic vortices. First, we show that when a driver combination of different vortex modes is used, HHG leads to the production of harmonic vortices with a broad OAM content due to its nonperturbative nature. Second, we show that harmonic vortices with two discrete OAM contributions -so called fractional OAM modes- are generated when HHG is driven by conical refraction beams. Our work offers the possibility of generating tunable OAM beams in the XUV regime, potentially extensible to the soft x rays, overcoming the state of the art limitations for the generation of OAM beams far from the visible domain.
Tang, Ruikai; Li, Xiongjie; Wu, Wenjie; Pan, Haifeng; Zeng, Heping; Wu, E
2015-04-20
The orbital angular momentum (OAM) of light shows great potential in quantum communication. The transmission wavelength for telecom is usually around 1550 nm, while the common quantum information storage and processing devices based on atoms, ions or NV color centers are for photons in visible regime. Here we demonstrate a quantum information interface based on the frequency upconversion for photons carrying OAM states from telecom wavelength to visible regime by sum-frequency generation with high quantum conversion efficiency. The infrared photons at 1558 nm carrying different OAM values were converted to the visible regime of 622.2 nm, and the OAM value of the signal photons was well preserved in the frequency upconversion process with pump beam in Gaussian profile.
Superposition of two optical vortices with opposite integer or non-integer orbital angular momentum
Directory of Open Access Journals (Sweden)
Carlos Fernando Díaz Meza
2016-04-01
Full Text Available This work develops a brief proposal to achieve the superposition of two opposite vortex beams, both with integer or non-integer mean value of the orbital angular momentum. The first part is about the generation of this kind of spatial light distributions through a modified Brown and Lohmann’s hologram. The inclusion of a simple mathematical expression into the pixelated grid’s transmittance function, based in Fourier domain properties, shifts the diffraction orders counterclockwise and clockwise to the same point and allows the addition of different modes. The strategy is theoretically and experimentally validated for the case of two opposite rotation helical wavefronts.
Controlling plasmonic orbital angular momentum by combining geometric and dynamic phases
Tan, Qilong; Liu, Hongchao; Huang, Xuguang; Zhang, Shuang
2016-01-01
Tunable orbit angular momentum (OAM) of surface plasmon polaritons (SPPs) is theoretically studied with appropriately designed metasurfaces. By controlling both the orientation angle and spatial position of nano aperture array on an ultrathin gold film, the field distributions of the surface waves can be engineered to contain both spin dependent and independent OAM components. Simultaneous control over the geometric phase and optical path difference induced phase (dynamic phase) provides extra degrees of freedom for manipulating OAM of SPPs. We show that arbitrary combination of OAM numbers can be realized for the SPPs excited by incident light of different circular polarizations. The results provides powerful control over the OAM of SPPs, which will have potential applications on optical trapping, imaging, communications and quantum information processing.
Li, Shuhui; Chen, Shi; Gao, Chunqing; Willner, Alan E.; Wang, Jian
2018-02-01
Orbital angular momentum (OAM)-carrying beams have recently generated considerable interest due to their potential use in communication systems to increase transmission capacity and spectral efficiency. For OAM-based free-space optical (FSO) links, a critical challenge is the atmospheric turbulence that will distort the helical wavefronts of OAM beams leading to the decrease of received power, introducing crosstalk between multiple channels, and impairing link performance. In this paper, we review recent advances in turbulence effects compensation techniques for OAM-based FSO communication links. First, basic concepts of atmospheric turbulence and theoretical model are introduced. Second, atmospheric turbulence effects on OAM beams are theoretically and experimentally investigated and discussed. Then, several typical turbulence compensation approaches, including both adaptive optics-based (optical domain) and signal processing-based (electrical domain) techniques, are presented. Finally, key challenges and perspectives of compensation of turbulence-distorted OAM links are discussed.
Transfer of orbital angular momentum of light using two-component slow light
Ruseckas, Julius; Kudriašov, Viačeslav; Yu, Ite A.; Juzeliūnas, Gediminas
2013-05-01
We study the manipulation of slow light with an orbital angular momentum propagating in a cloud of cold atoms. Atoms are affected by four co-propagating control laser beams in a double tripod configuration of the atomic energy levels involved, allowing us to minimize the losses at the vortex core of the control beams. In such a situation the atomic medium is transparent for a pair of co-propagating probe fields, leading to the creation of two-component (spinor) slow light. We study the interaction between the probe fields when two control beams carry optical vortices of opposite helicity. As a result, a transfer of the optical vortex takes place from the control to the probe fields without switching off and on the control beams. This feature is missing in a single tripod scheme where the optical vortex can be transferred from the control to the probe field only during either the storage or retrieval of light.
LDPC-coded orbital angular momentum (OAM) modulation for free-space optical communication.
Djordjevic, Ivan B; Arabaci, Murat
2010-11-22
An orbital angular momentum (OAM) based LDPC-coded modulation scheme suitable for use in FSO communication is proposed. We demonstrate that the proposed scheme can operate under strong atmospheric turbulence regime and enable 100 Gb/s optical transmission while employing 10 Gb/s components. Both binary and nonbinary LDPC-coded OAM modulations are studied. In addition to providing better BER performance, the nonbinary LDPC-coded modulation reduces overall decoder complexity and latency. The nonbinary LDPC-coded OAM modulation provides a net coding gain of 9.3 dB at the BER of 10(-8). The maximum-ratio combining scheme outperforms the corresponding equal-gain combining scheme by almost 2.5 dB.
Classical to quantum optical network link for orbital angular momentum-carrying light.
Zhou, Zhi-Yuan; Li, Yan; Ding, Dong-Sheng; Zhang, Wei; Shi, Shuai; Shi, Bao-Sen
2015-07-13
Using orbital angular momentum (OAM) conservation in second-order nonlinear interaction processes, we create a classical to quantum optical network link in the OAM degrees of freedom of light via sum frequency generation, followed by spontaneous parametric down-conversion. Coherent OAM-carrying beams at 1550 nm are up-converted to 525.5-nm OAM-carrying beams in the first crystal, and are used to pump a second crystal to generate non-degenerate OAM entangled photon pairs at 795 nm and 1550 nm. By switching the OAM carried by the classical part, OAM correlation in the quantum part is shifted. High-level OAM entanglements in two-dimensional subspaces are verified.
Deng, Yifan; Zhang, Hu; Li, Hui; Tang, Xianfeng; Xi, Lixia; Zhang, Wenbo; Zhang, Xiaoguang
2017-02-20
We propose a new orbital angular momentum (OAM) erbium-doped fiber amplifier based on a circular photonic crystal fiber, which can support a total of 18 modes (14 OAM modes) over C-band. A correction factor is proposed to modify the overlap factor, with the aim of evaluating the performance of the amplifier more accurately. We found that the confined doping profile can help optimize the differential model gain (DMG). Numerical simulations suggest that the proposed OAM fiber amplifier can provide a gain larger than 20 dB for all 14 OAM modes, with the small DMG less than 0.2 dB and the noise figure lower than 3.5 dB across the C-band.
Superposition of two optical vortices with opposite integer or non-integer orbital angular momentum
Directory of Open Access Journals (Sweden)
Carlos Fernando Díaz Meza
2016-01-01
Full Text Available This work develops a brief proposal to achieve the superposition of two opposite vortex beams, both with integer or non-integer mean value of the orbital angular momentum. The first part is about the generation of this kind of spatial light distributions through a modified Brown and Lohmann’s hologram. The inclusion of a simple mathematical expression into the pixelated grid’s transmittance function, based in Fourier domain properties, shifts the diffraction orders counterclockwise and clockwise to the same point and allows the addition of different modes. The strategy is theoretically and experimentally validated for the case of two opposite rotation helical wavefronts.
On-chip spin-controlled orbital angular momentum directional coupling
Xie, Zhenwei; Lei, Ting; Si, Guangyuan; Du, Luping; Lin, Jiao; Min, Changjun; Yuan, Xiaocong
2018-01-01
Optical vortex beams have many potential applications in the particle trapping, quantum encoding, optical orbital angular momentum (OAM) communications and interconnects. However, the on-chip compact OAM detection is still a big challenge. Based on a holographic configuration and a spin-dependent structure design, we propose and demonstrate an on-chip spin-controlled OAM-mode directional coupler, which can couple the OAM signal to different directions due to its topological charge. While the directional coupling function can be switched on/off by altering the spin of incident beam. Both simulation and experimental measurements verify the validity of the proposed approach. This work would benefit the on-chip OAM devices for optical communications and high dimensional quantum coding/decoding in the future.
All-fiber orbital angular momentum mode generation and transmission system
Heng, Xiaobo; Gan, Jiulin; Zhang, Zhishen; Qian, Qi; Xu, Shanhui; Yang, Zhongmin
2017-11-01
We proposed and demonstrated an all-fiber system for generating and transmitting orbital angular momentum (OAM) mode light. A specially designed multi-core fiber (MCF) was used to endow with guide modes different phase change and two tapered transition regions were used for providing low-loss interfaces between different fiber structures. By arranging the refractive index distribution among the multi-cores and controlling the length of MCF, which essentially change the phase difference between the neighboring cores, OAM modes with different topological charge l can be generated selectively. Through two tapered transition regions, the non-OAM mode light can be effectively injected into the MCF and the generated OAM mode light can be easily launched into OAM mode supporting fiber for long distance and high purity transmission. Such an all-fiber OAM mode generation and transmission system owns the merits of flexibility, compactness, portability, and would have practical application value in OAM optical fiber communication systems.
Ultrathin Complementary Metasurface for Orbital Angular Momentum Generation at Microwave Frequencies
Chen, Menglin L N; Sha, Wei E I
2016-01-01
Electromagnetic (EM) waves with helical wavefront carry orbital angular momentum (OAM), which is associated with the azimuthal phase of the complex electric field. OAM is a new degree of freedom in EM waves and is promising for channel multiplexing in communication system. Although the OAM-carrying EM wave attracts more and more attention, the method of OAM generation at microwave frequencies still faces challenges, such as efficiency and simulation time. In this work, by using the circuit theory and equivalence principle, we build two simplified models, one for a single scatter and one for the whole metasurface to predict their EM responses. Both of the models significantly simplify the design procedure and reduce the simulation time. In this paper, we propose an ultrathin complementary metasurface that converts a left-handed (right-handed) circularly polarized plane wave without OAM to a right-handed (left-handed) circularly polarized wave with OAM of arbitrary orders and a high transmission efficiency can ...
Quantum Key Distribution with High Order Fibonacci-like Orbital Angular Momentum States
Pan, Ziwen; Cai, Jiarui; Wang, Chuan
2017-08-01
The coding space in quantum communication could be expanded to high-dimensional space by using orbital angular momentum (OAM) states of photons, as both the capacity of the channel and security are enhanced. Here we present a novel approach to realize high-capacity quantum key distribution (QKD) by exploiting OAM states. The innovation of the proposed approach relies on a unique type of entangled-photon source which produces entangled photons with OAM randomly distributed among high order Fiboncci-like numbers and a new physical mechanism for efficiently sharing keys. This combination of entanglement with mathematical properties of high order Fibonacci sequences provides the QKD protocol immunity to photon-number-splitting attacks and allows secure generation of long keys from few photons. Unlike other protocols, reference frame alignment and active modulation of production and detection bases are unnecessary.
Zhou, Zhi-Yuan; Jiang, Yun-Kun; Li, Yan; Shi, Shuai; Wang, Xi-Shi; Shi, Bao-Sen; Guo, Guang-Can
2014-01-01
Light with helical phase structures, carrying quantized orbital angular momentum (OAM), has many applications in both classical and quantum optics, such as high-capacity optical communications and quantum information processing. Frequency conversion is a basic technique to expand the frequency range of fundamental light. The frequency conversion of OAM-carrying light gives rise to new physics and applications such as up-conversion detection of images and high dimensional OAM entanglements. Quasi-phase matching (QPM) nonlinear crystals are good candidates for frequency conversion, particularly for their high-valued effective nonlinear coefficients and no walk-off effect. Here we report the first experimental second-harmonic generation (SHG) of OAM light with a QPM crystal, where a UV light with OAM of 100 is generated. OAM conservation is verified using a specially designed interferometer. With a pump beam carrying an OAM superposition of opposite sign, we observed interesting interference phenomena in the SHG...
Trapping of light with angular orbital momentum above the light cone
Directory of Open Access Journals (Sweden)
E. Bulgakov
2017-01-01
Full Text Available We consider bound states in the radiation continuum (BSC above the light cone in an one-dimensional periodic array of dielectric spheres in air. The BSCs are classified by orbital angular momentum m, Bloch wave vector β directed along the array, and polarization. The most simple symmetry protected BSCs have m = 0, β = 0 and occur in a wide range of the radius of spheres and dielectric constant. More sophisticated BSCs with m ̸= 0, β = 0 exist only for a selected radius of the spheres at a fixed dielectric constant. We also show the existence of robust Bloch BSCs with β ̸=0, m = 0. The BSCs with m = 0 can be easily detected by the collapse of Fano resonance in scattering of a plane wave. In response to a plane wave with circular polarization the BSCs with m ̸= 0 give rise to Poynting vector spiralling around the array.
The detection of objects in a turbid underwater medium using orbital angular momentum (OAM)
Cochenour, Brandon; Rodgers, Lila; Laux, Alan; Mullen, Linda; Morgan, Kaitlyn; Miller, Jerome K.; Johnson, Eric G.
2017-05-01
We present an investigation of the optical property of orbital angular momentum (OAM) for use in the detection of objects obscured by a turbid underwater channel. In our experiment, a target is illuminated by a Gaussian beam. An optical vortex is formed by passing the object-reflected and backscattered light through a diffractive spiral phase plate at the receiver, which allows for the spatial separation of coherent and non-coherent light. This provides a method for discriminating target from environment. Initial laboratory results show that the ballistic target return can be detected 2-3 orders of magnitude below the backscatter clutter level. Furthermore, the detection of this coherent component is accomplished with the use of a complicated optical heterodyning scheme. The results suggest new optical sensing techniques for underwater imaging or LIDAR.
Constraining the angular momentum of the Sun with planetary orbital motions and general relativity
Iorio, Lorenzo
2011-01-01
The angular momentum of a star is an important astrophysical quantity related to its internal structure, formation and evolution. On average, helioseismology yields S = 1.92 10^41 kg m^2 s^-1 for the angular momentum of the Sun. We constrain it in a model-independent, dynamical way by using the gravitomagnetic Lense-Thirring effect predicted by general relativity for the orbit of a test particle moving around a central rotating body. The correction to the standard Einsteinian/Newtonian precession of the longitude of the perihelion $ of Mercury, recently inferred by a team of astronomers from a fit of dynamical models of the forces acting on the planets of the solar system to a long data record, amounts to 0.4 +/- 0.6 mas cty^-1. The modeled forces did not include the Lense-Thirring effect itself, which is expected to be as large as -2.0 mas cty^-1 for the perihelion of Mercury from helioseismological values of S?. By assuming the validity of general relativity, from its theoretical prediction for the gravitom...
2004-01-01
Following the introduction of Condensators, resistors and potentiometers from the Farnell electronic-catalogue into CERN Stores' catalogue, following products are now available: PRODUCT FAMILY GROUP SCEM Oscillators and quartz crystals 07.94.10 / 07.94.12 Diodes 08.51.14 / 08.51.54 Thyristors 08.51.60 / 08.51.66 Opto-electronics 08.52 Transistors 08.53 Integrated circuits 08.54 / 08.55 These articles can be procured in the same way as any other stores item, by completing a Material Request. N.B. Individual Farnell order codes can be used as keywords to facilitate searches in the CERN Stores Catalogue.
Quantum numbers of the $X(3872)$ state and orbital angular momentum in its $\\rho^0 J/\\psi$ decays
Aaij, Roel; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; d'Argent, Philippe; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Bel, Lennaert; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bertolin, Alessandro; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Birnkraut, Alex; Bizzeti, Andrea; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Braun, Svende; Brett, David; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Capriotti, Lorenzo; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carniti, Paolo; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casanova Mohr, Raimon; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cavallero, Giovanni; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cogoni, Violetta; Cojocariu, Lucian; Collazuol, Gianmaria; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Crocombe, Andrew; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dalseno, Jeremy; David, Pieter; Davis, Adam; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Silva, Weeraddana; De Simone, Patrizia; Dean, Cameron Thomas; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Dey, Biplab; Di Canto, Angelo; Di Ruscio, Francesco; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dufour, Laurent; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferrari, Fabio; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fol, Philip; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garofoli, Justin; Garra Tico, Jordi; Garrido, Lluis; Gascon, David; Gaspar, Clara; Gastaldi, Ugo; Gauld, Rhorry; Gavardi, Laura; Gazzoni, Giulio; Geraci, Angelo; Gerick, David; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Gianì, Sebastiana; Gibson, Valerie; Giubega, Lavinia-Helena; Gligorov, Vladimir; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graverini, Elena; Graziani, Giacomo; Grecu, Alexandru; Greening, Edward; Gregson, Sam; Griffith, Peter; Grillo, Lucia; Grünberg, Oliver; Gui, Bin; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Haines, Susan; Hall, Samuel; Hamilton, Brian; Hampson, Thomas; Han, Xiaoxue; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; He, Jibo; Head, Timothy; Heijne, Veerle; Hennessy, Karol; Henrard, Pierre; Henry, Louis; Hernando Morata, Jose Angel; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hoballah, Mostafa; Hombach, Christoph; Hulsbergen, Wouter; Humair, Thibaud; Hussain, Nazim; Hutchcroft, David; Hynds, Daniel; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jaeger, Andreas; Jalocha, Pawel; Jans, Eddy; Jawahery, Abolhassan; Jing, Fanfan; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kandybei, Sergii; Kanso, Walaa; Karacson, Matthias; Karbach, Moritz; Karodia, Sarah; Kelsey, Matthew; Kenyon, Ian; Kenzie, Matthew; Ketel, Tjeerd; Khanji, Basem; Khurewathanakul, Chitsanu; Klaver, Suzanne; Klimaszewski, Konrad; Kochebina, Olga; Kolpin, Michael; Komarov, Ilya; Koopman, Rose; Koppenburg, Patrick; Korolev, Mikhail; Kravchuk, Leonid; Kreplin, Katharina; Kreps, Michal; Krocker, Georg; Krokovny, Pavel; Kruse, Florian; Kucewicz, Wojciech; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kurek, Krzysztof; Kvaratskheliya, Tengiz; La Thi, Viet Nga; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lambert, Dean; Lambert, Robert W; Lanfranchi, Gaia; Langenbruch, Christoph; Langhans, Benedikt; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; van Leerdam, Jeroen; Lees, Jean-Pierre; Lefèvre, Regis; Leflat, Alexander; Lefrançois, Jacques; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Yiming; Likhomanenko, Tatiana; Liles, Myfanwy; Lindner, Rolf; Linn, Christian; Lionetto, Federica; Liu, Bo; Lohn, Stefan; Longstaff, Iain; Lopes, Jose; Lowdon, Peter; Lucchesi, Donatella; Luo, Haofei; Lupato, Anna; Luppi, Eleonora; Lupton, Oliver; Machefert, Frederic; Maciuc, Florin; Maev, Oleg; Maguire, Kevin; Malde, Sneha; Malinin, Alexander; Manca, Giulia; Mancinelli, Giampiero; Manning, Peter Michael; Mapelli, Alessandro; Maratas, Jan; Marchand, Jean François; Marconi, Umberto; Marin Benito, Carla; Marino, Pietro; Märki, Raphael; Marks, Jörg; Martellotti, Giuseppe; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massafferri, André; Matev, Rosen; Mathad, Abhijit; Mathe, Zoltan; Matteuzzi, Clara; Mauri, Andrea; Maurin, Brice; Mazurov, Alexander; McCann, Michael; McCarthy, James; McNab, Andrew; McNulty, Ronan; Meadows, Brian; Meier, Frank; Meissner, Marco; Merk, Marcel; Milanes, Diego Alejandro; Minard, Marie-Noelle; Mitzel, Dominik Stefan; Molina Rodriguez, Josue; Monteil, Stephane; Morandin, Mauro; Morawski, Piotr; Mordà, Alessandro; Morello, Michael Joseph; Moron, Jakub; Morris, Adam Benjamin; Mountain, Raymond; Muheim, Franz; Müller, Janine; Müller, Katharina; Müller, Vanessa; Mussini, Manuel; Muster, Bastien; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Neuner, Max; Nguyen, Anh Duc; Nguyen, Thi-Dung; Nguyen-Mau, Chung; Niess, Valentin; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Ninci, Daniele; Novoselov, Alexey; O'Hanlon, Daniel Patrick; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Ogilvy, Stephen; Okhrimenko, Oleksandr; Oldeman, Rudolf; Onderwater, Gerco; Osorio Rodrigues, Bruno; Otalora Goicochea, Juan Martin; Otto, Adam; Owen, Patrick; Oyanguren, Maria Aranzazu; Palano, Antimo; Palombo, Fernando; Palutan, Matteo; Panman, Jacob; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Parkes, Christopher; Passaleva, Giovanni; Patel, Girish; Patel, Mitesh; Patrignani, Claudia; Pearce, Alex; Pellegrino, Antonio; Penso, Gianni; Pepe Altarelli, Monica; Perazzini, Stefano; Perret, Pascal; Pescatore, Luca; Petridis, Konstantinos; Petrolini, Alessandro; Petruzzo, Marco; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pilař, Tomas; Pinci, Davide; Pistone, Alessandro; Playfer, Stephen; Plo Casasus, Maximo; Poikela, Tuomas; Polci, Francesco; Poluektov, Anton; Polyakov, Ivan; Polycarpo, Erica; Popov, Alexander; Popov, Dmitry; Popovici, Bogdan; Potterat, Cédric; Price, Eugenia; Price, Joseph David; Prisciandaro, Jessica; Pritchard, Adrian; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Punzi, Giovanni; Qian, Wenbin; Quagliani, Renato; Rachwal, Bartolomiej; Rademacker, Jonas; Rakotomiaramanana, Barinjaka; Rama, Matteo; Rangel, Murilo; Raniuk, Iurii; Rauschmayr, Nathalie; Raven, Gerhard; Redi, Federico; Reichert, Stefanie; Reid, Matthew; dos Reis, Alberto; Ricciardi, Stefania; Richards, Sophie; Rihl, Mariana; Rinnert, Kurt; Rives Molina, Vincente; Robbe, Patrick; Rodrigues, Ana Barbara; Rodrigues, Eduardo; Rodriguez Lopez, Jairo Alexis; Rodriguez Perez, Pablo; Roiser, Stefan; Romanovsky, Vladimir; Romero Vidal, Antonio; Rotondo, Marcello; Rouvinet, Julien; Ruf, Thomas; Ruiz, Hugo; Ruiz Valls, Pablo; Saborido Silva, Juan Jose; Sagidova, Naylya; Sail, Paul; Saitta, Biagio; Salustino Guimaraes, Valdir; Sanchez Mayordomo, Carlos; Sanmartin Sedes, Brais; Santacesaria, Roberta; Santamarina Rios, Cibran; Santimaria, Marco; Santovetti, Emanuele; Sarti, Alessio; Satriano, Celestina; Satta, Alessia; Saunders, Daniel Martin; Savrina, Darya; Schiller, Manuel; Schindler, Heinrich; Schlupp, Maximilian; Schmelling, Michael; Schmelzer, Timon; Schmidt, Burkhard; Schneider, Olivier; Schopper, Andreas; Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Semennikov, Alexander; Sepp, Indrek; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Shires, Alexander; Silva Coutinho, Rafael; Simi, Gabriele; Sirendi, Marek; Skidmore, Nicola; Skillicorn, Ian; Skwarnicki, Tomasz; Smith, Edmund; Smith, Eluned; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Soomro, Fatima; Souza, Daniel; Souza De Paula, Bruno; Spaan, Bernhard; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Steinkamp, Olaf; Stenyakin, Oleg; Sterpka, Christopher Francis; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Stroili, Roberto; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Swientek, Stefan; Syropoulos, Vasileios; Szczekowski, Marek; Szczypka, Paul; Szumlak, Tomasz; T'Jampens, Stephane; Tekampe, Tobias; Teklishyn, Maksym; Tellarini, Giulia; Teubert, Frederic; Thomas, Christopher; Thomas, Eric; van Tilburg, Jeroen; Tisserand, Vincent; Tobin, Mark; Todd, Jacob; Tolk, Siim; Tomassetti, Luca; Tonelli, Diego; Topp-Joergensen, Stig; Torr, Nicholas; Tournefier, Edwige; Tourneur, Stephane; Trabelsi, Karim; Tran, Minh Tâm; Tresch, Marco; Trisovic, Ana; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tuning, Niels; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vacca, Claudia; Vagnoni, Vincenzo; Valenti, Giovanni; Vallier, Alexis; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vázquez Sierra, Carlos; Vecchi, Stefania; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Vesterinen, Mika; Viaud, Benoit; Vieira, Daniel; Vieites Diaz, Maria; Vilasis-Cardona, Xavier; Vollhardt, Achim; Volyanskyy, Dmytro; Voong, David; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; de Vries, Jacco; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Walsh, John; Wandernoth, Sebastian; Wang, Jianchun; Ward, David; Watson, Nigel; Websdale, David; Weiden, Andreas; Whitehead, Mark; Wiedner, Dirk; Wilkinson, Guy; Wilkinson, Michael; Williams, Mark Richard James; Williams, Matthew; Williams, Mike; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wright, Simon; Wyllie, Kenneth; Xie, Yuehong; Xu, Zhirui; Yang, Zhenwei; Yuan, Xuhao; Yushchenko, Oleg; Zangoli, Maria; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Yanxi; Zhelezov, Alexey; Zhokhov, Anatoly; Zhong, Liang
2015-01-01
Angular correlations in $B^+\\to X(3872) K^+$ decays, with $X(3872)\\to \\rho^0 J/\\psi$, $\\rho^0\\to\\pi^+\\pi^-$ and $J/\\psi \\to\\mu^+\\mu^-$, are used to measure orbital angular momentum contributions and to determine the $J^{PC}$ value of the $X(3872)$ meson. The data correspond to an integrated luminosity of 3.0 fb$^{-1}$ of proton-proton collisions collected with the LHCb detector. This determination, for the first time performed without assuming a value for the orbital angular momentum, confirms the quantum numbers to be $J^{PC}=1^{++}$. The $X(3872)$ is found to decay predominantly through S wave and an upper limit of $4\\%$ at $95\\%$ C.L. is set on the fraction of D wave.
Berezin, M; Shavit, R
2015-01-01
The near fields in the proximity of a small ferrite particle with magnetic-dipolar-mode (MDM) oscillations have space and time symmetry breakings. Such MDM originated fields, called magnetoelectric (ME) fields, carry both spin and orbital angular momentums. By virtue of unique topology, ME fields are strongly different from free-space electromagnetic (EM) fields. In this paper, we show that because of chiral topology of ME fields in a nearfield region, far-field orbital angular momenta (OAM) can be observed, both numerically and experimentally. In a single element antenna, we obtain a radiation pattern with an angular squint. We reveal that in far field microwave radiation a crucial role is played by the ME energy distribution in the near-field region.
Quantum Communication with a Twist: QKD using Orbital Angular Momentum Photons
Miller, Warner; Sweiti, Ayman
2007-03-01
We briefly outline our progress in developing a programmable-optics QKD system that utilizes the orbital angular momentum (OAM) eigenstates of photons. A photon can be prepared in a state that exhibits both its polarization as well as OAM. A single photon with polarization can communicate one bit of information. However a single photon from an appropriate set of axial eigenstates (OAM or ``twisted photon'') can, in principle, transmit many bits. While there is no improvement in bandwidth over conventional spin-based QKD devises, the use of an OAM eigenmodes in an n-state QKD system can substantially reduce the system's optical fidelity requirements. We outline the relative strengths and weaknesses in using OAM states verses polarization states regarding the (1) state preparation, (2) state propagation and (3) state detection. An essential element of any QKD system is the generation, propagation and sorting of mutually unbiased (MUB) quantum states. We demonstrate here the diffractive optics generation of MUB states built from the superpositions in an n-dimensional Hilbert space of OAM photons. In particular, we show the generation of a MUB state utilizing a liquid crystal spatial light modulator.
Controlled generation of different orbital angular momentum states in a hybrid optical fiber
Heng, Xiaobo; Gan, Jiulin; Zhang, Zhishen; Qian, Qi; Xu, Shanhui; Yang, Zhongmin
2017-11-01
A new kind of hybrid optical fiber for different orbital angular momentum (OAM) states generation is proposed and investigated by simulation. The hybrid fiber is composed of three main regions: the core, the cladding and the bow-tie-shaped stress-applying zones (SAZs). The SAZs are symmetrically distributed on both sides of the core and filled with piezoelectric material PZT-5H which would generate radial mechanical movement when subjected to an electric field. The strain applied by the SAZs introduces anisotropic variation of the material permittivity which affect the propagation of the guided modes along the fiber core. The OAM modes of | l | = 1 , 2 , 3 can be generated by setting the appropriate electric potential applied in the SAZs. This fiber-based structure and electric control design enable the generation and adjustment of OAM states with the merits of accuracy, compactness and practicality, which would have potential application in OAM optical fiber communication systems and other systems utilizing OAM light.
Simultaneous and spatially separated detection of multiple orbital angular momentum states
Tudor, R.; Mihailescu, M.; Kusko, C.; Paun, I. A.; Nan, A. E.; Kusko, M.
2016-06-01
We present a method for spatially separated detection of multiple orbital angular momentum (OAM) states, simultaneous. The starting point is the generation of axially superposed Laguerre-Gauss beams, carrying multiple OAM states using a single computer generated hologram. The information contained in the OAM superposition is transferred to the first diffraction order and is detected at the receiver with a reading mask, which contains two perpendicular superposed fork-like holograms, ensuring the spatial separation of the OAM states. The dynamic of the process is studied in terms of the number of generated OAM states and the constructive parameters values. The experimental investigations use an optical arrangement based on a spatial light modulator in the transmitter unit and an amplitude mask in the receiver unit. This proof of concept experiment demonstrates the possibility of simultaneously detection of multiple OAM states in points located at different coordinates, controlled through the design of the holograms and shows the capability of our proposed method to increase the capacity of free-space optical communication channels.
Stimulated scattering of electromagnetic waves carrying orbital angular momentum in quantum plasmas.
Shukla, P K; Eliasson, B; Stenflo, L
2012-07-01
We investigate stimulated scattering instabilities of coherent circularly polarized electromagnetic (CPEM) waves carrying orbital angular momentum (OAM) in dense quantum plasmas with degenerate electrons and nondegenerate ions. For this purpose, we employ the coupled equations for the CPEM wave vector potential and the driven (by the ponderomotive force of the CPEM waves) equations for the electron and ion plasma oscillations. The electrons are significantly affected by the quantum forces (viz., the quantum statistical pressure, the quantum Bohm potential, as well as the electron exchange and electron correlations due to electron spin), which are included in the framework of the quantum hydrodynamical description of the electrons. Furthermore, our investigation of the stimulated Brillouin instability of coherent CPEM waves uses the generalized ion momentum equation that includes strong ion coupling effects. The nonlinear equations for the coupled CPEM and quantum plasma waves are then analyzed to obtain nonlinear dispersion relations which exhibit stimulated Raman, stimulated Brillouin, and modulational instabilities of CPEM waves carrying OAM. The present results are useful for understanding the origin of scattered light off low-frequency density fluctuations in high-energy density plasmas where quantum effects are eminent.
Deep-space and near-Earth optical communications by coded orbital angular momentum (OAM) modulation.
Djordjevic, Ivan B
2011-07-18
In order to achieve multi-gigabit transmission (projected for 2020) for the use in interplanetary communications, the usage of large number of time slots in pulse-position modulation (PPM), typically used in deep-space applications, is needed, which imposes stringent requirements on system design and implementation. As an alternative satisfying high-bandwidth demands of future interplanetary communications, while keeping the system cost and power consumption reasonably low, in this paper, we describe the use of orbital angular momentum (OAM) as an additional degree of freedom. The OAM is associated with azimuthal phase of the complex electric field. Because OAM eigenstates are orthogonal the can be used as basis functions for N-dimensional signaling. The OAM modulation and multiplexing can, therefore, be used, in combination with other degrees of freedom, to solve the high-bandwidth requirements of future deep-space and near-Earth optical communications. The main challenge for OAM deep-space communication represents the link between a spacecraft probe and the Earth station because in the presence of atmospheric turbulence the orthogonality between OAM states is no longer preserved. We will show that in combination with LDPC codes, the OAM-based modulation schemes can operate even under strong atmospheric turbulence regime. In addition, the spectral efficiency of proposed scheme is N2/log2N times better than that of PPM.
Ren, Yongxiong; Li, Long; Wang, Zhe; Kamali, Seyedeh Mahsa; Arbabi, Ehsan; Arbabi, Amir; Zhao, Zhe; Xie, Guodong; Cao, Yinwen; Ahmed, Nisar; Yan, Yan; Liu, Cong; Willner, Asher J.; Ashrafi, Solyman; Tur, Moshe; Faraon, Andrei; Willner, Alan E.
2016-09-01
To increase system capacity of underwater optical communications, we employ the spatial domain to simultaneously transmit multiple orthogonal spatial beams, each carrying an independent data channel. In this paper, we show up to a 40-Gbit/s link by multiplexing and transmitting four green orbital angular momentum (OAM) beams through a single aperture. Moreover, we investigate the degrading effects of scattering/turbidity, water current, and thermal gradient-induced turbulence, and we find that thermal gradients cause the most distortions and turbidity causes the most loss. We show systems results using two different data generation techniques, one at 1064 nm for 10-Gbit/s/beam and one at 520 nm for 1-Gbit/s/beam; we use both techniques since present data-modulation technologies are faster for infrared (IR) than for green. For the 40-Gbit/s link, data is modulated in the IR, and OAM imprinting is performed in the green using a specially-designed metasurface phase mask. For the 4-Gbit/s link, a green laser diode is directly modulated. Finally, we show that inter-channel crosstalk induced by thermal gradients can be mitigated using multi-channel equalisation processing.
Deep learning as a tool to distinguish between high orbital angular momentum optical modes
Knutson, E. M.; Lohani, Sanjaya; Danaci, Onur; Huver, Sean D.; Glasser, Ryan T.
2016-09-01
The generation of light containing large degrees of orbital angular momentum (OAM) has recently been demon- strated in both the classical and quantum regimes. Since there is no fundamental limit to how many quanta of OAM a single photon can carry, optical states with an arbitrarily high difference in this quantum number may, in principle, be entangled. This opens the door to investigations into high-dimensional entanglement shared between states in superpositions of nonzero OAM. Additionally, making use of non-zero OAM states can allow for a dramatic increase in the amount of information carried by a single photon, thus increasing the information capacity of a communication channel. In practice, however, it is difficult to differentiate between states with high OAM numbers with high precision. Here we investigate the ability of deep neural networks to differentiate between states that contain large values of OAM. We show that such networks may be used to differentiate be- tween nearby OAM states that contain realistic amounts of noise, with OAM values of up to 100. Additionally, we examine how the classification accuracy scales with the signal-to-noise ratio of images that are used to train the network, as well as those being tested. Finally, we demonstrate the simultaneous classification of < 100 OAM states with greater than 70 % accuracy. We intend to verify our system with experimentally-produced classi- cal OAM states, as well as investigate possibilities that would allow this technique to work in the few-photon quantum regime.
Measuring Orbital Angular Momentum (OAM) States of Vortex Beams with Annular Gratings.
Zheng, Shuang; Wang, Jian
2017-01-17
Measuring orbital angular momentum (OAM) states of vortex beams is of great importance in diverse applications employing OAM-carrying vortex beams. We present a simple and efficient scheme to measure OAM states (i.e. topological charge values) of vortex beams with annular gratings. The magnitude of the topological charge value is determined by the number of dark fringes after diffraction, and the sign of the topological charge value is distinguished by the orientation of the diffraction pattern. We first theoretically study the diffraction patterns using both annular amplitude and phase gratings. The annular phase grating shows almost 10-dB better diffraction efficiency compared to the annular amplitude grating. We then experimentally demonstrate the OAM states measurement of vortex beams using annular phase grating. The scheme works well even for high-order vortex beams with topological charge value as high as ± 25. We also experimentally show the evolution of diffraction patterns when slightly changing the fractional topological charge value of vortex beam from 0.1 to 1.0. In addition, the proposed scheme shows potential large tolerance of beam alignment during the OAM states measurement of vortex beams.
Simultaneous entanglement swapping of multiple orbital angular momentum states of light.
Zhang, Yingwen; Agnew, Megan; Roger, Thomas; Roux, Filippus S; Konrad, Thomas; Faccio, Daniele; Leach, Jonathan; Forbes, Andrew
2017-09-21
High-bit-rate long-distance quantum communication is a proposed technology for future communication networks and relies on high-dimensional quantum entanglement as a core resource. While it is known that spatial modes of light provide an avenue for high-dimensional entanglement, the ability to transport such quantum states robustly over long distances remains challenging. To overcome this, entanglement swapping may be used to generate remote quantum correlations between particles that have not interacted; this is the core ingredient of a quantum repeater, akin to repeaters in optical fibre networks. Here we demonstrate entanglement swapping of multiple orbital angular momentum states of light. Our approach does not distinguish between different anti-symmetric states, and thus entanglement swapping occurs for several thousand pairs of spatial light modes simultaneously. This work represents the first step towards a quantum network for high-dimensional entangled states and provides a test bed for fundamental tests of quantum science.Entanglement swapping in high dimensions requires large numbers of entangled photons and consequently suffers from low photon flux. Here the authors demonstrate entanglement swapping of multiple spatial modes of light simultaneously, without the need for increasing the photon numbers with dimension.
Controlling orbital angular momentum of an optical vortex by varying its ellipticity
Kotlyar, Victor V.; Kovalev, Alexey A.
2018-03-01
An exact analytical expression is obtained for the orbital angular momentum (OAM) of a Gaussian optical vortex with a different degree of ellipticity. The OAM turned out to be proportional to the ratio of two Legendre polynomials of adjoining orders. It is shown that if an elliptical optical vortex is embedded into the center of the waist of a circularly symmetrical Gaussian beam, then the normalized OAM of such laser beam is fractional and it does not exceed the topological charge n. If, on the contrary, a circularly symmetrical optical vortex is embedded into the center of the waist of an elliptical Gaussian beam, then the OAM is equal to n. If the optical vortex and the Gaussian beam have the same (or matched) ellipticity degree, then the OAM of the laser beam is greater than n. Continuous varying of the OAM of a laser beam by varying its ellipticity degree can be used in optical trapping for accelerated motion of microscopic particles along an elliptical trajectory as well as in quantum informatics for detecting OAM-entangled photons.
Wigner functions for angle and orbital angular momentum: Operators and dynamics
Kastrup, H. A.
2017-05-01
Recently a paper on the construction of consistent Wigner functions for cylindrical phase spaces S1×R , i.e., for the canonical pair angle and orbital angular momentum, was published [H. A. Kastrup, Phys. Rev. A 94, 062113 (2016), 10.1103/PhysRevA.94.062113] in which the main properties of these functions are derived and discussed and their usefulness is illustrated with examples. The present paper is a continuation which compares the properties of the Wigner functions for cylindrical phase spaces with those of the well-known Wigner functions for planar phase spaces in more detail. Furthermore, the mutual (Weyl) correspondence between Hilbert space operators and their phase-space functions is discussed. The product formalism is shown to be completely implementable. In addition, basic dynamical laws for Wigner and Moyal functions are derived as generalized Liouville and energy equations. They are very similar to those in the planar case but also show characteristic differences.
Ren, Yongxiong; Li, Long; Wang, Zhe; Kamali, Seyedeh Mahsa; Arbabi, Ehsan; Arbabi, Amir; Zhao, Zhe; Xie, Guodong; Cao, Yinwen; Ahmed, Nisar; Yan, Yan; Liu, Cong; Willner, Asher J.; Ashrafi, Solyman; Tur, Moshe; Faraon, Andrei; Willner, Alan E.
2016-01-01
To increase system capacity of underwater optical communications, we employ the spatial domain to simultaneously transmit multiple orthogonal spatial beams, each carrying an independent data channel. In this paper, we show up to a 40-Gbit/s link by multiplexing and transmitting four green orbital angular momentum (OAM) beams through a single aperture. Moreover, we investigate the degrading effects of scattering/turbidity, water current, and thermal gradient-induced turbulence, and we find that thermal gradients cause the most distortions and turbidity causes the most loss. We show systems results using two different data generation techniques, one at 1064 nm for 10-Gbit/s/beam and one at 520 nm for 1-Gbit/s/beam; we use both techniques since present data-modulation technologies are faster for infrared (IR) than for green. For the 40-Gbit/s link, data is modulated in the IR, and OAM imprinting is performed in the green using a specially-designed metasurface phase mask. For the 4-Gbit/s link, a green laser diode is directly modulated. Finally, we show that inter-channel crosstalk induced by thermal gradients can be mitigated using multi-channel equalisation processing. PMID:27615808
Ren, Yongxiong; Wang, Zhe; Kamali, Seyedeh Mahsa; Arbabi, Ehsan; Arbabi, Amir; Zhao, Zhe; Xie, Guodong; Cao, Yinwen; Ahmed, Nisar; Yan, Yan; Liu, Cong; Willner, Asher J; Ashrafi, Solyman; Tur, Moshe; Faraon, Andrei; Willner, Alan E
2016-01-01
To increase system capacity of underwater optical communications, we employ the spatial domain to simultaneously transmit multiple orthogonal spatial beams, each carrying an independent data channel. In this paper, we multiplex and transmit four green orbital angular momentum (OAM) beams through a single aperture. Moreover, we investigate the degrading effects of scattering/turbidity, water current, and thermal gradient-induced turbulence, and we find that thermal gradients cause the most distortions and turbidity causes the most loss. We show systems results using two different data generation techniques, one at 1064 nm for 10-Gbit/s/beam and one at 520 nm for 1-Gbit/s/beam, we use both techniques since present data-modulation technologies are faster for infrared (IR) than for green. For the higher-rate link, data is modulated in the IR, and OAM imprinting is performed in the green using a specially-designed metasurface phase mask. For the lower rates, a green laser diode is directly modulated. Finally, we s...
The Orbital Angular Momentum Modes Supporting Fibers Based on the Photonic Crystal Fiber Structure
Directory of Open Access Journals (Sweden)
Hu Zhang
2017-10-01
Full Text Available The orbital angular momentum (OAM of light can be another physical dimension that we exploit to make multiplexing in the spatial domain. The design of the OAM mode supporting fiber attracts many attentions in the field of the space division multiplexing (SDM system. This paper reviews the recent progresses in photonic crystal fiber (PCF supporting OAM modes, and summarizes why a PCF structure can be used to support stable OAM transmission modes. The emphasis is on the circular PCFs, which possess many excellent features of transmission performance, such as good-quality OAM modes, enough separation of the effective indices, low confinement loss, flat dispersion, a large effective area, and a low nonlinear coefficient. We also compare the transmission properties between the circular PCF and the ring core fiber, as well as the properties between the OAM EDFA based on circular PCF and the OAM EDFA based on the ring core fiber. At last, the challenges and prospects of OAM fibers based on the PCF structure are also discussed.
Liu, Baiyang; Lin, Guoying; Cui, Yuehui; Li, RongLin
2017-08-29
For purpose of utilizing orbital angular momentum (OAM) mode diversity, multiple OAM beams should be generated preferably by a single antenna. In this paper, an OAM mode reconfigurable antenna is proposed. Different from the existed OAM antennas with multiple ports for multiple OAM modes transmitting, the proposed antenna with only a single port, but it can be used to transmit mode 1 or mode -1 OAM beams arbitrary by controlling the PIN diodes on the feeding network through a programmable microcontroller which control by a remote controller. Simulation and measurement results such as return loss, near-field and far-field radiation patterns of two operating states for mode 1 and mode -1, and OAM mode orthogonality are given. The proposed antenna can serve as a candidate for utilizing OAM diversity, namely phase diversity to increase channel capacity at 2.4 GHz. Moreover, an OAM-mode based encoding method is experimentally carried out by the proposed OAM mode reconfigurable antenna, the digital data are encoded and decoded by different OAM modes. At the transmitter, the proposed OAM mode reconfigurable antenna is used to encode the digital data, data symbol 0 and 1 are mapped to OAM mode 1 and mode -1, respectively. At the receiver, the data symbols are decoded by phase gradient method.
Zou, Li; Wang, Le; Zhao, Shengmei
2017-10-01
Atmospheric turbulence (AT) induced crosstalk can significantly impair the performance of free-space optical (FSO) communication link using orbital angular momentum (OAM) multiplexing. In this paper, we propose a spatial diversity (SD) turbulence mitigation scheme in an OAM-multiplexed FSO communication link. First, we present a SD mitigation model for the OAM-multiplexed FSO communication link under AT. Then we present a SD combining technique based on equal gain to enhance AT tolerance of the OAM-multiplexed FSO communication link. The numerical results show that performance of the OAM-multiplexed communication link has greatly improved by the proposed scheme. When the turbulence strength Cn2 is 5 × 10-15m - 2 / 3, the transmission distance is 1000 m and the channel signal-to-noise ratio (SNR) is 20 dB, the bit-error-rate (BER) performance of four spatial multiplexed OAM modes lm = + 1 , + 2 , + 3 , + 4 are 3 fold increase in comparison with those results without the proposed scheme. The proposed scheme is a promising direction for compensating the interference caused by AT in the OAM-multiplexed FSO communication link.
Yan, Yan; Li, Long; Xie, Guodong; Bao, Changjing; Liao, Peicheng; Huang, Hao; Ren, Yongxiong; Ahmed, Nisar; Zhao, Zhe; Wang, Zhe; Ashrafi, Nima; Ashrafi, Solyman; Talwar, Shilpa; Sajuyigbe, Soji; Tur, Moshe; Molisch, Andreas F; Willner, Alan E
2016-09-23
Electromagnetic waves carrying orbital angular momentum (OAM) have been used for mode division multiplexing in free-space communication systems to increase both the capacity and the spectral efficiency. In the case of conventional wireless communication links using non-OAM beams, multipath effects caused by beam spreading and reflection from the surrounding objects affect the system performance. This paper presents the results of analysis, simulations, and measurements of multipath effects in a millimetre-wave communication link using OAM multiplexing at 28 GHz. Multipath-induced intra- and inter-channel crosstalk, which are caused by specular reflection from a plane parallel to the propagation path, are analysed and measured. Both the simulation and the experimental results show that an OAM channel with a high OAM number ℓ tends to suffer from both strong intra-channel crosstalk and strong inter-channel crosstalk with other OAM channels. Results of the analysis show that this observation can be explained on the basis of both the properties of OAM beam divergence and the filtering effect at the receiver, which is associated with the spiral wavefront of OAM beams.
SEE Observations of Ionospheric Heating from HAARP Using Orbital Angular Momentum
Briczinski, S. J.; Bernhardt, P. A.; Siefring, C. L.
2013-12-01
High power HF radio waves exciting the ionosphere provide aeronomers with a unique space-based laboratory capability. The High-Frequency Active Auroral Research Program (HAARP) in Gakona, Alaksa is the world's largest heating facility, providing effective radiated powers in the gigawatt range. Experiments performed at HAARP have allowed researchers to study many non-linear effects of wave-plasma interactions. Stimulated Electromagnetic Emission (SEE) is of interest to the ionospheric community for its diagnostic purposes. Typical SEE experiments at HAARP have focused on characterizing the parametric decay of the electromagnetic pump wave into several different wave modes such as upper and lower hybrid, ion acoustic, ion-Bernstein and electron-Bernstein. These production modes have been extensively studied at HAARP using traditional beam heating patterns and SEE detection. New results are present from HAARP experiments using an excitation mode that attempts to impart orbital angular momentum (OAM) into the heating region. This OAM mode is also referred to as a 'twisted beam.' Previous analysis of twisted beam heating shows that the SEE results obtained are nearly identical to the modes without OAM. Recent twisted beam heating experiments have produced SEE modes not previously characterized. These new modes are presented and discussed. One difference in the twisted beam mode is the heating region produced is in the shape of a ring as opposed to the more traditional 'solid spot' region. The ring heating pattern may be more conducive to the creation of artificial ionization clouds. The results of these runs include artificial ionization creation and evolution as pertaining to the twisted beam pattern.
Hu, Anguang; Chan, Nora W. C.; Dunlap, Brett I.
2017-08-01
The computation of s-type Gaussian pseudopotential matrix elements involving low powers of the distance from the pseudopotential center using Gaussian orbitals can be reduced to familiar integrals. They may be directly expressed as either simple three-center overlap integrals for even powers of the radial distance from the pseudopotential center or related to the three-center nuclear integrals of a Gaussian charge distribution for odd powers. Orbital angular momentum about each atom is added to these integrals by solid-harmonic differentiation with respect to its center. The solid-harmonic addition theorem allows all the integrals to be factored into products of invariant one-dimensional integrals involving the Gaussian exponents and angular factors that contain the azimuthal quantum numbers but are independent of all Gaussian exponents. Precomputing the angular factors allow looping over all Gaussian exponents about the three centers. The fact that solid harmonics are eigenstates of angular momentum removes the singularities seen in previous treatments of pseudopotential matrix elements.
Arita, Yoshihiko; Mazilu, Michael; Chen, Mingzhou; Vettenburg, Tom; Auñón, Juan M.; Wright, Ewan M.; Dholakia, Kishan
2017-04-01
We demonstrate the transfer of orbital angular momentum to optically levitated microparticles in vacuum [1]. We prepare two-dimensional and three-dimensional optical potentials. In the former case the microparticle is placed within a Laguerre-Gaussian beam and orbits the annular beam profile with increasing angular velocity as the air drag coefficient is reduced. We explore the particle dynamics as a function of the topological charge of the levitating beam. Our results reveal that there is a fundamental limit to the orbital angular momentum that may be transferred to a trapped particle, dependent upon the beam parameters and inertial forces present. This effect was predicted theoretically [2] and can be understood considering the underlying dynamics arising from the link between the magnitude of the azimuthal index and the beam radius [3]. Whilst a Laguerre-Gaussian beam scales in size with azimuthal index `, recently we have created a "perfect" vortex beam whose radial intensity profile and radius are both independent of topological charge [4, 5]. As the Fourier transform of a perfect vortex yields a Bessel beam. Imaging a perfect vortex, with its subsequent propagation thus realises a complex three dimensional optical field. In this scenario we load individual silica microparticles into this field and observe their trajectories. The optical gradient and scattering forces interplay with the inertial and gravitational forces acting on the trapped particle, including the rotational degrees of freedom. As a result the trapped microparticle exhibits a complex three dimensional motion that includes a periodic orbital motion between the Bessel and the perfect vortex beam. We are able to determine the three dimensional optical potential in situ by tracking the particle. This first demonstration of trapping microparticles within a complex three dimensional optical potential in vacuum opens up new possibilities for fundamental studies of many-body dynamics, mesoscopic
DEFF Research Database (Denmark)
Angelsky, O. V.; Bekshaev, A. Ya; Maksimyak, P. P.
2012-01-01
The internal energy flow in a light beam can be divided into the "orbital" and "spin" parts, associated with the spatial and polarization degrees of freedom of light. In contrast to the orbital one, experimental observation of the spin flow seems problematic because it is converted into an orbital...... flow upon tight focusing of the beam, usually applied for energy flow detection by means of the mechanical action upon probe particles. We propose a two-beam interference technique that results in an appreciable level of spin flow in moderately focused beams and detection of the orbital motion of probe...... particles within a field where the transverse energy circulation is associated exclusively with the spin flow. This result can be treated as the first demonstration of mechanical action of the spin flow of a light field....
Energy Technology Data Exchange (ETDEWEB)
Ramsey, G.P.; Qui, J.; Richards, D.; Sivers, D.
1989-01-01
New data from the European Muon Collaboration (EMC) on the spin-spin asymmetry in deep-inelastic lepton-proton scattering suggests that the total spin carried by valence quarks in a polarized proton may be approximately canceled by a strong negative polarization of the sea of q-barq pairs. The evolution in Q/sup 2/ of the fraction of proton spin carried by gluons depends on the initial spin fractions and it is possible to avoid the introduction of large orbital angular momentum by adopting a ''hybrid'' quark-Skyrme picture of the proton suggested by the EMC results.
Toda, Y.; Moriya, H.; Shigematsu, K.; Yamane, K.; Morita, R.; Awaji, Y.
2017-04-01
Single angular momentum (OAM) mode emissions from a vertical cavity surface emitting laser (VCSEL) were demonstrated by an external optical feedback using computer generated holograms, which are optimized on the OAM modal gain of the free-running VCSEL. Side-mode suppression ratio of more than 23 dB was achieved for the OAM modes with l = +/-1.
Piccirillo, Bruno; Slussarenko, Sergei; Marrucci, Lorenzo; Santamato, Enrico
2015-10-19
The standard method for experimentally determining the probability distribution of an observable in quantum mechanics is the measurement of the observable spectrum. However, for infinite-dimensional degrees of freedom, this approach would require ideally infinite or, more realistically, a very large number of measurements. Here we consider an alternative method which can yield the mean and variance of an observable of an infinite-dimensional system by measuring only a two-dimensional pointer weakly coupled with the system. In our demonstrative implementation, we determine both the mean and the variance of the orbital angular momentum of a light beam without acquiring the entire spectrum, but measuring the Stokes parameters of the optical polarization (acting as pointer), after the beam has suffered a suitable spin-orbit weak interaction. This example can provide a paradigm for a new class of useful weak quantum measurements.
Orbital Angular Momentum of Gauge Fields: Excitation of AN Atom by Twisted Photons
Afanasev, Andrei; Carlson, Carl E.; Mukherjee, Asmita
2014-01-01
Twisted photon states, or photon states with large (> ℏ) angular momentum projection in the direction of motion, can photoexcite atomic final states of differing quantum numbers. If the photon symmetry axis coincides with the center of an atom, there are known selection rules that require exact matching between the quantum numbers of the photon and the photoexcited states. The more general case of arbitrarily positioned beams relaxes the selection rules but produces a distribution of quantum numbers of the final atomic states that is novel and distinct from final states produced by plane-wave photons. Numerical calculations are presented using a hydrogen atom as an example.
Angular and energy dependence of (e,e{sup `}) cross sections for orbital 1{sup +} excitations
Energy Technology Data Exchange (ETDEWEB)
Nojarov, R. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik; Faessler, A. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik; Dingfelder, M. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik
1996-02-19
The main features of the (e,e`) cross sections of low-lying orbital excitations with K{sup {pi}}=1{sup +} in heavy deformed nuclei are studied in RPA on the example of {sup 156}Gd. The dependence of the DWBA E2 and M1 cross sections on the scattering angle 0 {sup circle} <{theta}<180 {sup circle} and incident electron energy E{sub i} < 210 MeV is analyzed in PWBA. The cross section is larger for M1 than for E2 transitions at any angle if E{sub i}<30 MeV. The longitudinal (Coulomb) C2 excitation dominates the E2 response for 5 {sup circle} <{theta}<170 {sup circle}. Only transverse M1 and E2 excitations compete for {theta}>175 {sup circle} and the former one is dominant for q<1.2 fm{sup -1}. The M1 response is almost purely orbital up to q=1.4 fm{sup -1} even in backward scattering. Qualitative PWBA estimates based on the q-dependence of the form factors alone are not able to predict some important features of the (e,e`) cross sections stemming from the strong magnetic and orbital character of the studied 1{sup +} excitations. The expectation for M1 over E2 dominance in backward scattering should not be extended to higher momentum transfers and incident energies. (orig.).
Jia, Qikun; Qiu, Xiaodong; Wu, Ziwen; Zhang, Wuhong; Chen, Lixiang
2017-08-01
We build a modified Mach-Zehnder (M-Z) interferometer with an embedded Dove prism in one arm to observe the interference between two conjugate orbital angular momentum (OAM) beams. By inserting and moving an optical wedge vertically in the other arm, we find that its linear motion can induce a rotational frequency shift equivalently, as a consequence of phase transfer from the path difference to the azimuthal difference between two OAM beams. The micron-scale movement of the wedge is driven by a compact motorized translation stage and is manifested by a significant rotation of the interference petal-like patterns. Our scheme offers an accurate method to measure the optical wedge angle with a simple method of digital image processing. This work may also find potential applications in the field of velocity sensing or temperature sensing.
Chen, Shi; Liu, Jun; Zhao, Yifan; Zhu, Long; Wang, Andong; Li, Shuhui; Du, Jing; Du, Cheng; Mo, Qi; Wang, Jian
2016-11-30
We present a full-duplex bidirectional data transmission link using twisted lights multiplexing over 1.1-km orbital angular momentum (OAM) fiber. OAM+1 and OAM-1 modes carrying 20-Gbit/s quadrature phase-shift keying (QPSK) signals are employed in the downlink and uplink transmission experiments. The observed mode crosstalks are less than -15.2 dB, and the full-duplex crosstalks are less than -12.7 dB. The measured full-duplex optical signal-to-noise ratio (OSNR) penalties at a bit-error rate (BER) of 2 × 10(-3) are ~2.4 dB in the downlink transmission and ~2.3 dB in the uplink transmission. The obtained results show favorable full-duplex twisted lights multiplexing data transmission performance in a km-scale OAM fiber link.
Ren, Yongxiong; Wang, Zhe; Liao, Peicheng; Li, Long; Xie, Guodong; Huang, Hao; Zhao, Zhe; Yan, Yan; Ahmed, Nisar; Willner, Asher; Lavery, Martin P J; Ashrafi, Nima; Ashrafi, Solyman; Bock, Robert; Tur, Moshe; Djordjevic, Ivan B; Neifeld, Mark A; Willner, Alan E
2016-02-01
We experimentally demonstrate and characterize the performance of a 400-Gbit/s orbital angular momentum (OAM) multiplexed free-space optical link over 120 m on the roof of a building. Four OAM beams, each carrying a 100-Gbit/s quadrature-phase-shift-keyed channel are multiplexed and transmitted. We investigate the influence of channel impairments on the received power, intermodal crosstalk among channels, and system power penalties. Without laser tracking and compensation systems, the measured received power and crosstalk among OAM channels fluctuate by 4.5 dB and 5 dB, respectively, over 180 s. For a beam displacement of 2 mm that corresponds to a pointing error less than 16.7 μrad, the link bit error rates are below the forward error correction threshold of 3.8×10(-3) for all channels. Both experimental and simulation results show that power penalties increase rapidly when the displacement increases.
Li, Ya-qing; Wang, Li-guo
2017-11-01
On the basis of the extended Huygens-Fresnel principle and the cross-spectral density function (CSDF), the intensity and average orbital angular momentum (OAM) of the partially coherent flat-topped vortex beams in the slant atmospheric turbulence are presented. The effects of the order, topological charge, waist radius, and propagation distance of the beam on the intensity and average OAM are discussed. Results obtained show that the intensity of the partially coherent flat-topped vortex beam is changed due to the variations of the propagation distance, waist radius, topological charge and beam order, the average OAM is constant during the beam propagation in the atmospheric turbulence and related only to the waist radius and beam order. Results obtained by this paper may serve as theory bases for future applications in the atmospheric optical communication.
Ren, Yongxiong; Wang, Zhe; Xie, Guodong; Li, Long; Cao, Yinwen; Liu, Cong; Liao, Peicheng; Yan, Yan; Ahmed, Nisar; Zhao, Zhe; Willner, Asher; Ashrafi, Nima; Ashrafi, Solyman; Linquist, Roger D; Bock, Robert; Tur, Moshe; Molisch, Andreas F; Willner, Alan E
2015-09-15
We explore the potential of combining the advantages of multiple-input multiple-output (MIMO)-based spatial multiplexing with those of orbital angular momentum (OAM) multiplexing to increase the capacity of free-space optical (FSO) communications. We experimentally demonstrate an 80 Gbit/s FSO system with a 2×2 aperture architecture, in which each transmitter aperture contains two multiplexed data-carrying OAM modes. Inter-channel crosstalk effects are minimized by the OAM beams' inherent orthogonality and by the use of 4×4 MIMO signal processing. Our experimental results show that the bit-error rates can reach below the forward error correction limit of 3.8×10(-3) and the power penalties are less than 3.6 dB for all channels after MIMO processing. This indicates that OAM and MIMO-based spatial multiplexing could be simultaneously utilized, thereby providing the potential to enhance system performance.
Huang, Hao; Cao, Yinwen; Xie, Guodong; Ren, Yongxiong; Yan, Yan; Bao, Changjing; Ahmed, Nisar; Neifeld, Mark A; Dolinar, Samuel J; Willner, Alan E
2014-08-01
We demonstrate crosstalk mitigation using 4×4 multiple-input-multiple-output (MIMO) equalization on an orbital angular momentum (OAM) multiplexed free-space data link with heterodyne detection. Four multiplexed OAM beams, each carrying a 20 Gbit/s quadrature phase-shift keying signal, propagate through weak turbulence. The turbulence induces inter-channel crosstalk among each beam and degrades the signal performance. Experimental results demonstrate that with the assistance of MIMO processing, the signal quality and the bit-error-rate (BER) performance can be improved. The power penalty can be reduced by >4 dB at a BER of 3.8×10-3.
Yang, Chunyong; Xu, Chuang; Ni, Wenjun; Gan, Yu; Hou, Jin; Chen, Shaoping
2017-10-16
A novel scheme is proposed to mitigate the atmospheric turbulence effect in free space optical (FSO) communication employing orbital angular momentum (OAM) multiplexing. In this scheme, the Gaussian beam is used as an auxiliary light with a common-path to obtain the distortion information caused by atmospheric turbulence. After turbulence, the heterodyne coherent detection technology is demonstrated to realize the turbulence mitigation. With the same turbulence distortion, the OAM beams and the Gaussian beam are respectively utilized as the signal light and the local oscillation light. Then the turbulence distortion is counteracted to a large extent. Meanwhile, a phase matching method is proposed to select the specific OAM mode. The discrimination between the neighboring OAM modes is obviously improved by detecting the output photocurrent. Moreover, two methods of beam size adjustment have been analyzed to achieve better performance for turbulence mitigation. Numerical results show that the system bit error rate (BER) can reach 10-5 under strong turbulence in simulation situation.
Fernando, J.; Schmidt, F.; Douté, S.
2016-09-01
The surface of Mars has a high morphological and mineralogical diversity due to the intricacy of external, internal processes, and exchanges with the atmosphere, the hydrosphere and the cryosphere. In particular, liquid water played an important role in surface evolution. However, the origin, duration and intensity of those wet events have been highly debated, especially in the clay-bearing geological units. Similarly, questions still remain about magma crystallization and volatile quantity of the dominant basaltic crust. In this work, six sites having hydrated minerals, salts and basaltic signatures (i.e., Mawrth Vallis, Holden crater, Eberswalde crater, Capri mensa, Eridania basin, Terra Sirenum) are investigated in order to better characterize the geological processes responsible for their formation and evolution (e.g., fluvial, lacustrine, in situ weathering, evaporitic, volcanic and aeolian processes). For that purpose, we use orbital multi-angular measurements from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument on-board the Mars Reconnaissance Orbiter spacecraft to analyze the manner in which light is scattered by the surface materials (photometry) in the near-infrared range (at 750 nm). The surface bidirectional reflectance depends on the composition but also on the surface microtexture such as the grain size distribution, morphology, internal structure and surface roughness, tracers of the geological processes. The Hapke semi-analytical model of radiative transfer in granular medium is used to model the surface bidirectional reflectance estimated at 750 nm from the orbital measurements after an atmospheric correction. The model depends on different radiative properties (e.g., single scattering albedo, grain phase function and regolith roughness) related to the surface composition and microtexture. In particular previous laboratory works showed that the particle phase function parameters, which describe the characteristics of the
Li, Ye; Yu, Lin; Zhang, Yixin
2017-05-29
Applying the angular spectrum theory, we derive the expression of a new Hermite-Gaussian (HG) vortex beam. Based on the new Hermite-Gaussian (HG) vortex beam, we establish the model of the received probability density of orbital angular momentum (OAM) modes of this beam propagating through a turbulent ocean of anisotropy. By numerical simulation, we investigate the influence of oceanic turbulence and beam parameters on the received probability density of signal OAM modes and crosstalk OAM modes of the HG vortex beam. The results show that the influence of oceanic turbulence of anisotropy on the received probability of signal OAM modes is smaller than isotropic oceanic turbulence under the same condition, and the effect of salinity fluctuation on the received probability of the signal OAM modes is larger than the effect of temperature fluctuation. In the strong dissipation of kinetic energy per unit mass of fluid and the weak dissipation rate of temperature variance, we can decrease the effects of turbulence on the received probability of signal OAM modes by selecting a long wavelength and a larger transverse size of the HG vortex beam in the source's plane. In long distance propagation, the HG vortex beam is superior to the Laguerre-Gaussian beam for resisting the destruction of oceanic turbulence.
DEFF Research Database (Denmark)
Liu, Jun; Li, Shimao; Ding, Yunhong
2016-01-01
We experimentally demonstrate orbital angular momentum (OAM) mode emission from a high emission efficiency OAM emitter for 20 Gbit/s QPSK carrying data transmission in few-mode fiber (FMF). Two modes propagate through a 3.6km three-mode FMF with measured OSNR penalties less than 4 dB at a BER of 2e...
Compositing orbital angular momentum beams in Bi4Ge3O12 crystal for magnetic field sensing
Yu, Shuangfeng; Pang, Fufei; Liu, Huanhuan; Li, Xianjin; Yang, Junfeng; Wang, Tingyun
2017-08-01
The polarization states and orbital angular momentum (OAM) properties of light are of considerable importance for several aspects of high-precision optical measurements. In this work, we have investigated the properties of composited OAM beams propagating in a Bi4Ge3O12 crystal under an applied magnetic field and have demonstrated a magnetic field sensing method based on compositing of OAM beams using a Sagnac configuration. The polarization rotation can be projected into petal-like patterns by the rotation of the OAM beams. However, the accurate measurement of the rotation angles of the petal-like patterns of OAM beams remains challenging. Therefore, an image processing technique based on the Radon transform is explored to enable the accurate calculation of the rotation angle of the petal-like patterns of composite OAM beams under different magnetic fields. The rotation angle of these petal-like patterns is found to have a linear dependence on the magnetic field intensity, which means that the proposed system is appropriate for magnetic field sensing applications. Using this method, a magnetic field sensitivity of 28°/T has been achieved experimentally with a measurement error of 0.0123 T in a high-intensity magnetic field ranging from 191 to 3322 G for OAM beams with topological charge (TC) l =±1 .
Murshid, Syed H.; Muralikrishnan, Hari P.; Kozaitis, Samuel P.
2012-06-01
Bandwidth increase has always been an important area of research in communications. A novel multiplexing technique known as Spatial Domain Multiplexing (SDM) has been developed at the Optronics Laboratory of Florida Institute of Technology to increase the bandwidth to T-bits/s range. In this technique, space inside the fiber is used effectively to transmit up to four channels of same wavelength at the same time. Experimental and theoretical analysis shows that these channels follow independent helical paths inside the fiber without interfering with each other. Multiple pigtail laser sources of exactly the same wavelength are used to launch light into a single carrier fiber in a fashion that resulting channels follow independent helical trajectories. These helically propagating light beams form optical vortices inside the fiber and carry their own Orbital Angular Momentum (OAM). The outputs of these beams appear as concentric donut shaped rings when projected on a screen. This endeavor presents the experimental outputs and simulated results for a four channel spatially multiplexed system effectively increasing the system bandwidth by a factor of four.
Wang, Andong; Zhu, Long; Chen, Shi; Du, Cheng; Mo, Qi; Wang, Jian
2016-05-30
Mode-division multiplexing over fibers has attracted increasing attention over the last few years as a potential solution to further increase fiber transmission capacity. In this paper, we demonstrate the viability of orbital angular momentum (OAM) modes transmission over a 50-km few-mode fiber (FMF). By analyzing mode properties of eigen modes in an FMF, we study the inner mode group differential modal delay (DMD) in FMF, which may influence the transmission capacity in long-distance OAM modes transmission and multiplexing. To mitigate the impact of large inner mode group DMD in long-distance fiber-based OAM modes transmission, we use low-density parity-check (LDPC) codes to increase the system reliability. By evaluating the performance of LDPC-coded single OAM mode transmission over 50-km fiber, significant coding gains of >4 dB, 8 dB and 14 dB are demonstrated for 1-Gbaud, 2-Gbaud and 5-Gbaud quadrature phase-shift keying (QPSK) signals, respectively. Furthermore, in order to verify and compare the influence of DMD in long-distance fiber transmission, single OAM mode transmission over 10-km FMF is also demonstrated in the experiment. Finally, we experimentally demonstrate OAM multiplexing and transmission over a 50-km FMF using LDPC-coded 1-Gbaud QPSK signals to compensate the influence of mode crosstalk and DMD in the 50 km FMF.
Qu, Zhen; Djordjevic, Ivan B
2017-08-15
We propose and experimentally demonstrate a two-stage cross-talk mitigation method in an orbital-angular-momentum (OAM)-based free-space optical communication system, which is enabled by combining spatial offset and low-density parity-check (LDPC) coded nonuniform signaling. Different from traditional OAM multiplexing, where the OAM modes are centrally aligned for copropagation, the adjacent OAM modes (OAM states 2 and -6 and OAM states -2 and 6) in our proposed scheme are spatially offset to mitigate the mode cross talk. Different from traditional rectangular modulation formats, which transmit equidistant signal points with uniform probability, the 5-quadrature amplitude modulation (5-QAM) and 9-QAM are introduced to relieve cross-talk-induced performance degradation. The 5-QAM and 9-QAM formats are based on the Huffman coding technique, which can potentially achieve great cross-talk tolerance by combining them with corresponding nonbinary LDPC codes. We demonstrate that cross talk can be reduced by 1.6 dB and 1 dB via spatial offset for OAM states ±2 and ±6, respectively. Compared to quadrature phase shift keying and 8-QAM formats, the LDPC-coded 5-QAM and 9-QAM are able to bring 1.1 dB and 5.4 dB performance improvements in the presence of atmospheric turbulence, respectively.
Energy Technology Data Exchange (ETDEWEB)
Gao, Xinlu [State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Applied Optics Beijing Area Major Laboratory, Department of Physics, Beijing Normal University, Beijing 100875 (China); Huang, Shanguo, E-mail: shghuang@bupt.edu.cn; Wei, Yongfeng; Zhai, Wensheng; Xu, Wenjing; Yin, Shan; Gu, Wanyi [State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Zhou, Jing [Applied Optics Beijing Area Major Laboratory, Department of Physics, Beijing Normal University, Beijing 100875 (China)
2014-12-15
A system of generating and receiving orbital angular momentum (OAM) radio beams, which are collectively formed by two circular array antennas (CAAs) and effectively optimized by two intensity controlled masks, is proposed and experimentally investigated. The scheme is effective in blocking of the unwanted OAM modes and enhancing the power of received radio signals, which results in the capacity gain of system and extended transmission distance of the OAM radio beams. The operation principle of the intensity controlled masks, which can be regarded as both collimator and filter, is feasible and simple to realize. Numerical simulations of intensity and phase distributions at each key cross-sectional plane of the radio beams demonstrate the collimated results. The experimental results match well with the theoretical analysis and the receive distance of the OAM radio beam at radio frequency (RF) 20 GHz is extended up to 200 times of the wavelength of the RF signals, the measured distance is 5 times of the original measured distance. The presented proof-of-concept experiment demonstrates the feasibility of the system.
Ren, Yongxiong; Liu, Cong; Pang, Kai; Zhao, Jiapeng; Cao, Yinwen; Xie, Guodong; Li, Long; Liao, Peicheng; Zhao, Zhe; Tur, Moshe; Boyd, Robert W; Willner, Alan E
2017-12-01
We experimentally demonstrate spatial multiplexing of an orbital angular momentum (OAM)-encoded quantum channel and a classical Gaussian beam with a different wavelength and orthogonal polarization. Data rates as large as 100 MHz are achieved by encoding on two different OAM states by employing a combination of independently modulated laser diodes and helical phase holograms. The influence of OAM mode spacing, encoding bandwidth, and interference from the co-propagating Gaussian beam on registered photon count rates and quantum bit error rates is investigated. Our results show that the deleterious effects of intermodal crosstalk effects on system performance become less important for OAM mode spacing Δ≥2 (corresponding to a crosstalk value of less than -18.5 dB). The use of OAM domain can additionally offer at least 10.4 dB isolation besides that provided by wavelength and polarization, leading to a further suppression of interference from the classical channel.
Design of a compact device to generate and test beams with orbital angular momentum in the EUV.
Pabon, D O; Ledesma, S A; Quinteiro, G F; Capeluto, M G
2017-10-10
We present a compact design to generate and test optical-vortex beams with possible applications in the extreme ultraviolet (EUV) region of the electromagnetic spectrum. The device consists of a diffractive mask where both the beam with orbital angular momentum and the reference wavefront to test its phase are generated. In order to show that the proposal would work in the EUV, simulations and proof-of-principle experiments were performed, using typical parameters for EUV holography scaled to visible wavelengths. As the simplest case, we consider the well-known Laguerre-Gaussian (LG)-like beams, which have a single vortex in the propagation axis. To further test the versatility of the device, we consider Mathieu beams, more complex structured beams that may contain several vortices. In the experiment, a spatial light modulator was used to display the mask. As examples, we show the results for a LG-like beam with topological charge ℓ=1 and Mathieu beams with topological charge ℓ=2 and ellipticity q=2. These results show the potential of the device to generate a variety of beam shapes at EUV wavelengths.
Gao, Jie; Zhang, Yixin; Dan, Weiyi; Hu, Zhengda
2015-06-29
The turbulent effects of strong irradiance fluctuations on the probability densities and the normalized powers of the orbital angular momentum (OAM) modes are modeled for fractional Bessel Gauss beams in paraxial turbulence channel. We find that the probability density of signal OAM modes is a function of position deviation from the beam center, and the farther away from the beam center the detection position is, the smaller the probability density is. For fractional OAM quantum numbers, the average probability densities of signal/crosstalk modes oscillate along the beam radius except the half-integer. When the beam waist of source decreases or the irradiance fluctuation increases, the average probability density of the signal OAM mode drops. The peak of the average probability density of crosstalk modes shifts to outward of the beam center as beam waist gets larger. In the nearby region of beam center, the larger the quantum number deviation of OAM, the smaller the beam waist and the turbulence fluctuations are, the lower average probability densities of crosstalk OAM modes are. Especially, the increase of turbulence fluctuations can make the crosstalk stronger and more concentrated. Lower irradiance fluctuation can give rise to higher the normalized powers of the signal OAM modes, which is opposite to the crosstalk normalized powers.
Han, Ya; Liu, Yan-Ge; Wang, Zhi; Huang, Wei; Chen, Lei; Zhang, Hong-Wei; Yang, Kang
2018-01-01
Mode-division multiplexing (MDM) is a promising technology for increasing the data-carrying capacity of a single few-mode optical fiber. The flexible mode manipulation would be highly desired in a robust MDM network. Recently, orbital angular momentum (OAM) modes have received wide attention as a new spatial mode basis. In this paper, we firstly proposed a long period fiber grating (LPFG) system to realize mode conversions between the higher order LP core modes in four-mode fiber. Based on the proposed system, we, for the first time, demonstrate the controllable all-fiber generation and conversion of the higher order LP core modes to the first and second order circularly polarized OAM beams with all the combinations of spin and OAM. Therefore, the proposed LPFG system can be potentially used as a controllable higher order OAM beam switch and a physical layer of the translating protocol from the conventional LP modes communication to the OAM modes communication in the future mode carrier telecommunication system and light calculation protocols.
Sun, Wenbo; Hu, Yongxiang; Weimer, Carl; Ayers, Kirk; Baize, Rosemary R.; Lee, Tsengdar
2017-02-01
Electromagnetic (EM) beams with orbital angular momentum (OAM) may have great potential applications in communication technology and in remote sensing of the Earth-atmosphere system and outer planets. Study of their interaction with optical lenses and dielectric or metallic objects, or scattering of them by particles in the Earth-atmosphere system, is a necessary step to explore the advantage of the OAM EM beams. In this study, the 3-dimensional (3D) scattered-field (SF) finite-difference time domain (FDTD) technique with the convolutional perfectly matched layer (CPML) absorbing boundary conditions (ABC) is applied to calculate the scattering of the purely azimuthal (the radial mode number is assumed to be zero) Laguerre-Gaussian (LG) beams with the OAM by dielectric particles. We found that for OAM beam's interaction with dielectric particles, the forward-scattering peak in the conventional phase function (P11) disappears, and light scattering peak occurs at a scattering angle of 15° to 45°. The disappearance of forward-scattering peak means that, in laser communications most of the particle-scattered noise cannot enter the receiver, thus the received light is optimally the original OAM-encoded signal. This feature of the OAM beam also implies that in lidar remote sensing of the atmospheric particulates, most of the multiple-scattering energy will be off lidar sensors, and this may result in an accurate profiling of particle layers in the atmosphere or in the oceans by lidar, or even in the ground when a ground penetration radar (GPR) with the OAM is applied. This far-field characteristics of the scattered OAM light also imply that the optical theorem, which is derived from plane-parallel wave scattering case and relates the forward scattering amplitude to the total cross section of the scatterer, is invalid for the scattering of OAM beams by dielectric particles.
Wang, Le; Zhao, Sheng-Mei; Gong, Long-Yan; Cheng, Wei-Wen
2015-12-01
In this paper, we propose a measurement-device-independent quantum-key-distribution (MDI-QKD) protocol using orbital angular momentum (OAM) in free space links, named the OAM-MDI-QKD protocol. In the proposed protocol, the OAM states of photons, instead of polarization states, are used as the information carriers to avoid the reference frame alignment, the decoy-state is adopted to overcome the security loophole caused by the weak coherent pulse source, and the high efficient OAM-sorter is adopted as the measurement tool for Charlie to obtain the output OAM state. Here, Charlie may be an untrusted third party. The results show that the authorized users, Alice and Bob, could distill a secret key with Charlie’s successful measurements, and the key generation performance is slightly better than that of the polarization-based MDI-QKD protocol in the two-dimensional OAM cases. Simultaneously, Alice and Bob can reduce the number of flipping the bits in the secure key distillation. It is indicated that a higher key generation rate performance could be obtained by a high dimensional OAM-MDI-QKD protocol because of the unlimited degree of freedom on OAM states. Moreover, the results show that the key generation rate and the transmission distance will decrease as the growth of the strength of atmospheric turbulence (AT) and the link attenuation. In addition, the decoy states used in the proposed protocol can get a considerable good performance without the need for an ideal source. Project supported by the National Natural Science Foundation of China (Grant Nos. 61271238 and 61475075), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20123223110003), the Natural Science Research Foundation for Universities of Jiangsu Province of China (Grant No. 11KJA510002), the Open Research Fund of Key Laboratory of Broadband Wireless Communication and Sensor Network Technology, Ministry of Education, China (Grant No. NYKL2015011), and the
Hemsing, Erik Willard
The object of this work is to examine how coherent light that carries orbital angular momentum (OAM) can be generated and amplified in a single pass, high-gain free-electron laser (FEL) at the fundamental operating frequency. This concept unites two rapidly expanding, but at present largely non-overlapping fields of study: high-order OAM light modes, which interact in new ways with matter, and FELs, in which a relativistically energetic electron beam emits coherent, ultra high-brightness, highly frequency-tunable light. The ability to generate OAM light in an FEL enables new regimes of laser interaction physics to be explored at wavelengths down to hard x-rays. The theoretical portion of this dissertation attempts to provide a new predictive mathematical framework. It builds on existing work, and describes the three-dimensional electromagnetic field of the high-gain FEL as a sum of OAM modes such that the amplification properties of individual modes can be characterized. The effects of uncorrelated energy spread, longitudinal space charge, energy detuning, and transverse emittance in the electron beam are included, as is the diffraction of the laser light. Theoretical predictions are corroborated by detailed numerical Genesis 1.3 simulations. When the theory is extended to frequency harmonics, a novel interaction is uncovered that generates a helical electron beam density distribution. These predictions are also supported by numerical Tredi simulations. This type of highly correlated structure is shown to naturally emit OAM light, and forms the basis of a new high-gain, high-mode generation (HGHMG) scheme proposed in its entirety here. The experimental section examines the helical microbunching concept in a proof-of-principle experiment dubbed HELIX, performed at the UCLA Neptune laboratory. We present detailed measurement of the coherent transition radiation emitted by the 12.5 MeV electron beam that is microbunched in a second harmonic interaction with an input
Ren, Yongxiong; Wang, Zhe; Liao, Peicheng; Li, Long; Xie, Guodong; Huang, Hao; Zhao, Zhe; Yan, Yan; Ahmed, Nisar; Willner, Asher; Lavery, Martin P. J.; Ashrafi, Nima; Ashrafi, Solyman; Bock, Robert; Tur, Moshe
2016-01-01
We experimentally demonstrate and characterize the\\ud performance of a 400-Gbit/s orbital angular momentum\\ud (OAM) multiplexed free-space optical link over 120-\\ud meters on the roof of a building. Four OAM beams, each\\ud carrying a 100-Gbit/s QPSK channel are multiplexed and\\ud transmitted. We investigate the influence of channel\\ud impairments on the received power, inter-modal\\ud crosstalk among channels, and system power penalties.\\ud Without laser tracking and compensation systems, the\\...
Wu, Zhenkun; Gu, Yuzong
2016-12-01
The propagation of two-dimensional beams is analytically and numerically investigated in strongly nonlocal nonlinear media (SNNM) based on the ABCD matrix. The two-dimensional beams reported in this paper are described by the product of the superposition of generalized Laguerre-Gaussian (LG), Hermite-Gaussian (HG), Bessel-Gaussian (BG), and circular Airy (CA) beams, carrying an orbital angular momentum (OAM). Owing to OAM and the modulation of SNNM, we find that the propagation of these two-dimensional beams exhibits complete rotation and periodic inversion: the spatial intensity profile first extends and then diminishes, and during the propagation the process repeats to form a breath-like phenomenon.
Janković, Marija R
2016-01-01
We use 57 recently found topological satellites of Broucke-Hadjidemetriou-Henon's periodic orbits with values of the topological exponent $k$ ranging from $k$ = 3 to $k$ = 58 to plot the angular momentum $L$ as a function of the period $T$, with both $L$ and $T$ rescaled to energy $E=-\\frac12$. Upon plotting $L(T/k)$ we find that all our solutions fall on a curve that is virtually indiscernible by naked eye from the $L(T)$ curve for non-satellite solutions. The standard deviation of the satellite data from the sixth-order polynomial fit to the progenitor data is $\\sigma = 0.13$. This regularity supports Henon's 1976 conjecture that the linearly stable Broucke-Hadjidemetriou-Henon orbits are also perpetually, or Kolmogorov-Arnold-Moser stable.
Xu, Guochang
2008-01-01
This is the first book of the satellite era which describes orbit theory with analytical solutions of the second order with respect to all possible disturbances. Based on such theory, the algorithms of orbits determination are completely revolutionized.
Xie, Guodong; Ren, Yongxiong; Huang, Hao; Lavery, Martin P J; Ahmed, Nisar; Yan, Yan; Bao, Changjing; Li, Long; Zhao, Zhe; Cao, Yinwen; Willner, Moshe; Tur, Moshe; Dolinar, Samuel J; Boyd, Robert W; Shapiro, Jeffrey H; Willner, Alan E
2015-04-01
A stochastic-parallel-gradient-descent algorithm (SPGD) based on Zernike polynomials is proposed to generate the phase correction pattern for a distorted orbital angular momentum (OAM) beam. The Zernike-polynomial coefficients for the correction pattern are obtained by monitoring the intensity profile of the distorted OAM beam through an iteration-based feedback loop. We implement this scheme and experimentally show that the proposed approach improves the quality of the turbulence-distorted OAM beam. Moreover, we apply phase correction patterns derived from a probe OAM beam through emulated turbulence to correct other OAM beams transmitted through the same turbulence. Our experimental results show that the patterns derived this way simultaneously correct multiple OAM beams propagating through the same turbulence, and the crosstalk among these modes is reduced by more than 5 dB.
Zhu, Yun; Zhang, Yixin; Yang, Guofeng
2017-12-01
In order to investigate the evolution of mode probability density (MPD) and received power of orbital angular momentum (OAM) mode carried by autofocusing Hypergeometric-Gaussian (HyGG) beams in moderate-to-strong anisotropic non-Kolmogorov turbulence, the corresponding expressions of the spatial coherence radius and spiral spectrum of HyGG beams are achieved. Results show that the autofocusing property of HyGG beams has a significant impact on the propagation of the MPD. Smaller topological charge, Shorter wavelength, higher values of hollowness parameters and wider beam waist shrink to a narrower width of the MPD and maintain the characteristic of diffraction-free with a longer transmission distance. Moreover, smaller outer-scale, larger inner-scale, larger non-Kolmogorov parameter and larger anisotropic coefficient make the received power of OAM suffer less turbulence.
Mella, Massimo
2009-09-28
In this work, collisions between rotating atomic clusters composed of Lennard-Jones (LJ(n)) particles and an identical projectile have been investigated by means of trajectory simulations as a function of the cluster angular momentum J and internal energy E, and for different values of the projectile impact parameter b and relative velocity v(p). As expected, the collision (P(c)(b)) and capture [or sticking P(s)(b)] probabilities are found to decay below unity for values of b larger than the average surface radius of the cluster, with dP/db being strongly dependent on v(p). Both P(c)(b) and P(s)(b), however, appear to be largely insensitive to the modulus of the cluster angular momentum |J| and only weakly dependent on E for collisions involving target clusters with a lifetime tau>100 ps. The latter findings are interpreted as indicating the absence of strong changes in the structure of the target as a function of |J| and E. The comparison between the dissociation lifetime (tau(dyn)) of the postcapture complexes (LJ(n+1)(*)) obtained continuing trajectories after monomer capture and the one computed from the fragmentation of statistically prepared clusters (tau(stat)) supports the validity of a two-step capture-dissociation model; similarly, the comparison between the average amount of energy exchanged during trajectories (DeltaE(dyn)) in the process LJ(n)+LJ-->LJ(n+1)(*)-->LJ(n)+LJ and the one predicted by statistical simulations (DeltaE(stat)) suggests a fast statistical energy redistribution in the collisional complex even for very short tau(dyn) (e.g., 40 ps). In the case of projectiles aimed at the edge of the cluster [(grazing collisions, P(c)(b)trajectories indicate the presence of ballistic dynamics and of a weak energy exchange (DeltaE(coll)
Yourshaw, Matthew Stephen
2017-01-01
Orbital is a virtual reality gaming experience designed to explore the use of traditional narrative structure to enhance immersion in virtual reality. The story structure of Orbital was developed based on the developmental steps of 'The Hero's Journey,' a narrative pattern identified by Joseph Campbell. Using this standard narrative pattern, Orbital is capable of immersing the player quickly and completely for the entirety of play time. MFA
Bellan, Paul
2015-11-01
Analytic solutions are presented for the orbit of a charged particle in the combination of a uniform axial magnetic field and a parabolic electrostatic potential. These trajectories are shown to correspond to the sum of two individually rotating vectors with one vector rotating at a constant fast frequency and the other rotating in the same sense but with a constant slow frequency. These solutions are related to the diocotron mode, to Penning trap orbits, and to stochastic orbits. If the lengths of the two rotating vectors are identical, the particle has zero canonical angular momentum in which case the particle orbit will traverse the origin. Axis-encircling orbits are where the length of the vector associated with the fast frequency is longer than the vector associated with the slow frequency. Non-axis encircling orbits are the other way around.
Krot, A. M.
2013-09-01
This work develops a statistical theory of gravitating spheroidal bodies to calculate the orbits of planets and explore forms of planetary orbits with regard to the Alfvén oscillating force [1] in the Solar system and other exoplanetary systems. The statistical theory of formation of gravitating spheroidal bodies has been proposed in [2]-[5]. Starting the conception for forming a spheroidal body inside a gas-dust protoplanetary nebula, this theory solves the problem of gravitational condensation of a gas-dust protoplanetary cloud with a view to planetary formation in its own gravitational field [3] as well as derives a new law of the Solar system planetary distances which generalizes the wellknown laws [2], [3]. This work also explains an origin of the Alfvén oscillating force modifying forms of planetary orbits within the framework of the statistical theory of gravitating spheroidal bodies [5]. Due to the Alfvén oscillating force moving solid bodies in a distant zone of a rotating spheroidal body have elliptic trajectories. It means that orbits for the enough remote planets from the Sun in Solar system are described by ellipses with focus in the origin of coordinates and with small eccentricities. The nearby planet to Sun named Mercury has more complex trajectory. Namely, in case of Mercury the angular displacement of a Newtonian ellipse is observed during its one rotation on an orbit, i.e. a regular (century) shift of the perihelion of Mercury' orbit occurs. According to the statistical theory of gravitating spheroidal bodies [2]-[5] under the usage of laws of celestial mechanics in conformity to cosmogonic bodies (especially, to stars) it is necessary to take into account an extended substance called a stellar corona. In this connection the stellar corona can be described by means of model of rotating and gravitating spheroidal body [5]. Moreover, the parameter of gravitational compression α of a spheroidal body (describing the Sun, in particular) has been
Murshid, Syed; Alanzi, Saud; Hridoy, Arnob; Lovell, Greg; Parhar, Gurinder; Chakravarty, Abhijit; Chowdhury, Bilas
2014-09-01
Spatial Domain Multiplexing/Space Division Multiplexing (SDM) can increase the bandwidth of existing and futuristic optical fibers by an order of magnitude or more. In the SDM technique, we launch multiple single mode pigtail laser sources of same wavelength into a carrier fiber at different angles. The launching angles decide the output of the carrier fiber by allocating separate spatial locations for each channel. Each channel follows a helical trajectory while traversing the length of the carrier fiber, thereby allowing spatial reuse of optical frequencies. In this endeavor we launch light from five different single mode pigtail laser sources at different angles (with respect to the axis of the carrier fiber) into the carrier fiber. Owing to helical propagation we get five distinct concentric donut shaped rings with negligible crosstalk at the output end of the fiber. These SDM channels also exhibit Orbital Angular Momentum (OAM), thereby adding an extra degree of photon freedom. We present the experimental data of five spatially multiplexed channels and compare them with simulated results to show that this technique can potentially improve the data capacity of optical fibers by an order of magnitude: A factor of five using SDM and another factor of two using OAM.
Murshid, Syed; Alanzi, Saud; Hridoy, Arnob; Lovell, Gregory L.; Parhar, Gurinder; Chakravarty, Abhijit; Chowdhury, Bilas
2016-06-01
Spatial domain multiplexing/space division multiplexing (SDM) can increase the bandwidth of existing and futuristic optical fibers by an order of magnitude or more. In the SDM technique, we launch multiple single-mode pigtail laser sources of the same wavelength into a carrier multimode fiber at different angles. The launching angles decide the output of the carrier fiber by allocating separate spatial locations for each channel. Each channel follows a helical trajectory while traversing the length of the carrier fiber, thereby allowing spatial reuse of optical frequencies. We launch light from five different single-mode pigtail laser sources (of same wavelength) at different angles (with respect to the axis of the carrier fiber) into the carrier fiber. Owing to helical propagation, five distinct concentric donut-shaped rings with negligible crosstalk at the output end of the fiber were obtained. These SDM channels also exhibit orbital angular momentum (OAM), thereby adding an extradegree of photon freedom. We present the experimental data of five spatially multiplexed channels and compare them with simulated results to show that this technique can potentially improve the data capacity of optical fibers by an order of magnitude: A factor of five using SDM and another factor of two using OAM.
Xie, Guodong; Zhao, Zhe; Yan, Yan; Li, Long; Ren, Yongxiong; Ahmed, Nisar; Cao, Yinwen; Willner, Asher J.; Bao, Changjing; Wang, Zhe; Liu, Cong; Ziyadi, Morteza; Talwar, Shilpa; Sajuyigbe, Soji; Ashrafi, Solyman; Tur, Moshe; Molisch, Andreas F.; Willner, Alan E.
2016-01-01
In line-of-sight communication systems, accurate alignment between the transmitter and receiver is important to guarantee sufficient signal power at the receiver. Such alignment is even more important for orbital angular momentum (OAM) multiplexing systems since misalignment between the transmitter and receiver may cause crosstalk among channels. In this paper, we demonstrate the simultaneous generation and tunable steering of two OAM beams utilising a custom-designed circular antenna array at 28 GHz. We achieve a steering angle of up to 35 degrees from the antenna array normal. We find that (i) the steering angle of the generated OAM beams is limited by the emitting angle of the antenna elements, and (ii) a larger steering angle may degrade the mode purity of the generated OAM beams as well as induce inter-symbol-interference to each of the individual channels. Moreover, we demonstrate the transmission of two 1-Gbaud quadratic phase shift keying (QPSK) signal over the two steerable OAM beams with both multiplexed channels achieved bit error rates (BERs) of <3.8 × 10−3. PMID:27833168
Li, Long; Zhang, Runzhou; Zhao, Zhe; Xie, Guodong; Liao, Peicheng; Pang, Kai; Song, Haoqian; Liu, Cong; Ren, Yongxiong; Labroille, Guillaume; Jian, Pu; Starodubov, Dmitry; Lynn, Brittany; Bock, Robert; Tur, Moshe; Willner, Alan E
2017-12-12
We explore the use of orbital-angular-momentum (OAM)-multiplexing to increase the capacity of free-space data transmission to moving platforms, with an added potential benefit of decreasing the probability of data intercept. Specifically, we experimentally demonstrate and characterize the performance of an OAM-multiplexed, free-space optical (FSO) communications link between a ground transmitter and a ground receiver via a moving unmanned-aerial-vehicle (UAV). We achieve a total capacity of 80 Gbit/s up to 100-m-roundtrip link by multiplexing 2 OAM beams, each carrying a 40-Gbit/s quadrature-phase-shift-keying (QPSK) signal. Moreover, we investigate for static, hovering, and moving conditions the effects of channel impairments, including: misalignments, propeller-induced airflows, power loss, intermodal crosstalk, and system bit error rate (BER). We find the following: (a) when the UAV hovers in the air, the power on the desired mode fluctuates by 2.1 dB, while the crosstalk to the other mode is -19 dB below the power on the desired mode; and (b) when the UAV moves in the air, the power fluctuation on the desired mode increases to 4.3 dB and the crosstalk to the other mode increases to -10 dB. Furthermore, the channel crosstalk decreases with an increase in OAM mode spacing.
Ndagano, Bienvenu; Mphuthi, Nokwazi; Milione, Giovanni; Forbes, Andrew
2017-10-15
There is interest in using orbital angular momentum (OAM) modes to increase the data speed of free-space optical communication. A prevalent challenge is the mitigation of mode-crosstalk and mode-dependent loss that is caused by the modes' lateral displacement at the data receiver. Here, the mode-crosstalk and mode-dependent loss of laterally displaced OAM modes (LG 0,+1 , LG 0,-1 ) are experimentally compared to that of a Hermite-Gaussian (HG) mode subset (HG 0,1 , HG 1,0 ). It is shown, for an aperture larger than the modes' waist sizes, some of the HG modes can experience less mode-crosstalk and mode-dependent loss when laterally displaced along a symmetry axis. It is also shown, over a normal distribution of lateral displacements whose standard deviation is 2× the modes' waist sizes, on average, the HG modes experience 66% less mode-crosstalk and 17% less mode-dependent loss.
Huang, Hao; Milione, Giovanni; Lavery, Martin P. J.; Xie, Guodong; Ren, Yongxiong; Cao, Yinwen; Ahmed, Nisar; An Nguyen, Thien; Nolan, Daniel A.; Li, Ming-Jun; Tur, Moshe; Alfano, Robert R.; Willner, Alan E.
2015-01-01
Mode division multiplexing (MDM)– using a multimode optical fiber’s N spatial modes as data channels to transmit N independent data streams – has received interest as it can potentially increase optical fiber data transmission capacity N-times with respect to single mode optical fibers. Two challenges of MDM are (1) designing mode (de)multiplexers with high mode selectivity (2) designing mode (de)multiplexers without cascaded beam splitting’s 1/N insertion loss. One spatial mode basis that has received interest is that of orbital angular momentum (OAM) modes. In this paper, using a device referred to as an OAM mode sorter, we show that OAM modes can be (de)multiplexed over a multimode optical fiber with higher than −15 dB mode selectivity and without cascaded beam splitting’s 1/N insertion loss. As a proof of concept, the OAM modes of the LP11 mode group (OAM−1,0 and OAM+1,0), each carrying 20-Gbit/s polarization division multiplexed and quadrature phase shift keyed data streams, are transmitted 5km over a graded-index, few-mode optical fibre. Channel crosstalk is mitigated using 4 × 4 multiple-input-multiple-output digital-signal-processing with <1.5 dB power penalties at a bit-error-rate of 2 × 10−3. PMID:26450398
Optical angular momentum and atoms.
Franke-Arnold, Sonja
2017-02-28
Any coherent interaction of light and atoms needs to conserve energy, linear momentum and angular momentum. What happens to an atom's angular momentum if it encounters light that carries orbital angular momentum (OAM)? This is a particularly intriguing question as the angular momentum of atoms is quantized, incorporating the intrinsic spin angular momentum of the individual electrons as well as the OAM associated with their spatial distribution. In addition, a mechanical angular momentum can arise from the rotation of the entire atom, which for very cold atoms is also quantized. Atoms therefore allow us to probe and access the quantum properties of light's OAM, aiding our fundamental understanding of light-matter interactions, and moreover, allowing us to construct OAM-based applications, including quantum memories, frequency converters for shaped light and OAM-based sensors.This article is part of the themed issue 'Optical orbital angular momentum'. © 2017 The Author(s).
Hanson, Robert M.
2003-06-01
ORBITAL requires the following software, which is available for free download from the Internet: Netscape Navigator, version 4.75 or higher, or Microsoft Internet Explorer, version 5.0 or higher; Chime Plug-in, version compatible with your OS and browser (available from MDL).
Zhu, Guoxuan; Hu, Ziyang; Wu, Xiong; Du, Cheng; Luo, Wenyong; Chen, Yujie; Cai, Xinlun; Liu, Jie; Zhu, Jiangbo; Yu, Siyuan
2018-01-22
We propose and demonstrate a scalable mode division multiplexing scheme based on orbital angular momentum modes in ring core fibers. In this scheme, the high-order mode groups of a ring core fiber are sufficiently de-coupled by the large differential effective refractive index so that multiple-input multiple-output (MIMO) equalization is only used for crosstalk equalization within each mode group. We design and fabricate a graded-index ring core fiber that supports 5 mode groups with low inter-mode-group coupling, small intra-mode-group differential group delay, and small group velocity dispersion slope over the C-band for the high-order mode groups. We implement a two-dimensional wavelength- and mode-division multiplexed transmission experiment involving 10 wavelengths and 2 mode groups each with 4 OAM modes, transmitting 32 GBaud Nyquist QPSK signals over all 80 channels. An aggregate capacity of 5.12 Tb/s and an overall spectral efficiency of 9 bit/s/Hz over 10 km are realized, only using modular 4x4 MIMO processing with 15 taps to recover signals from the intra-mode-group mode coupling. Given the fixed number of modes in each mode group and the low inter-mode-group coupling in ring core fibres, our scheme strikes a balance in the trade-off between system capacity and digital signal processing complexity, and therefore has good potential for capacity upscaling at an expense of only modularly increasing the number of mode-groups with fixed-size (4x4) MIMO blocks.
Zamudio-Bayer, V; Langenberg, A; Lawicki, A; Terasaki, A; Issendorff, B v; Lau, J T
2015-01-01
The $^6\\Delta$ electronic ground state of the Co$_2^+$ diatomic molecular cation has been assigned experimentally by x-ray absorption and x-ray magnetic circular dichroism spectroscopy in a cryogenic ion trap. Three candidates, $^6\\Phi$, $^6\\Gamma$, and $^8\\Gamma$, for the electronic ground state of Fe$_2^+$ have been identified. These states carry sizable ground-state orbital angular momenta that disagree with theoretical predictions from multireference configuration interaction and density functional theory. Our results show that the ground states of neutral and cationic diatomic molecules of $3d$ elements cannot be assumed to be connected by a one-electron process.
Lei, Ning; Xiong, Xiaoxiong
2016-01-01
Using an onboard sunlit solar diffuser (SD) as the primary radiance source, the visible infrared imaging radiometer suite (VIIRS) on the Suomi National Polar-orbiting Partnership satellite regularly performs radiometric calibration of its reflective solar bands (RSBs). The SD bidirectional reflectance distribution function (BRDF) value decreases over time. A numerical degradation factor is used to quantify the degradation and is determined by an onboard SD stability monitor (SDSM), which observes the sun and the sunlit SD at almost the same time. We had shown previously that the BRDF degradation factor was angle-dependent. Consequently, due to that the SDSM and the RSB view the SD at very different angles relative to both the solar and the SD surface normal vectors, directly applying the BRDF degradation factor determined by the SDSM to the VIIRS RSB calibration can result in large systematic errors. We develop a phenomenological model to calculate the BRDF degradation factor for the RSB SD view from the degradation factor for the SDSM SD view. Using the yearly undulations observed in the VIIRS detector gains for the M1-M4 bands calculated with the SD BRDF degradation factor for the SDSM SD view and the difference between the VIIRS detector gains calculated from the SD and the lunar observations, we obtain the model parameter values and thus establish the relation between the BRDF degradation factors for the RSB and the SDSM SD view directions.
Does high harmonic generation conserve angular momentum?
Fleischer, Avner; Diskin, Tzvi; Sidorenko, Pavel; Cohen, Oren
2013-01-01
High harmonic generation (HHG) is a unique and useful process in which infrared or visible radiation is frequency up converted into the extreme ultraviolet and x ray spectral regions. As a parametric process, high harmonic generation should conserve the radiation energy, momentum and angular momentum. Indeed, conservation of energy and momentum have been demonstrated. Angular momentum of optical beams can be divided into two components: orbital and spin (polarization). Orbital angular momentum is assumed to be conserved and recently observed deviations were attributed to propagation effects. On the other hand, conservation of spin angular momentum has thus far never been studied, neither experimentally nor theoretically. Here, we present the first study on the role of spin angular momentum in extreme nonlinear optics by experimentally generating high harmonics of bi chromatic elliptically polarized pump beams that interact with isotropic media. While observing that the selection rules qualitatively correspond...
Orbital-angular-momentum entanglement in turbulence
CSIR Research Space (South Africa)
Hamadou Ibrahim, A
2013-06-01
Full Text Available (finite-dimensional) subspace of the complete OAM Hilbert space. The orthogonal complement of this subspace does not represent any information. Although the quantum state of the photon pair is initially prepared to lie completely within the information... information is transferred to the environment, which is assumed to form a tensor product with the information-carrying quantum system. In the OAM case the information is lost to a part of the same Hilbert space. This is a drawback of OAM-based systems compared...
Amplitude damping channel for orbital angular momentum
CSIR Research Space (South Africa)
Dudley, Angela L
2010-03-01
Full Text Available of a previously reported OAM sorting device. A Mech-Zehnder interferometer with a Dove prism in each arm is used to sort OAM states according to their parity. The authors extend this concept to implement an amplitude damping channel, and prove its...
Karpov, Valeri
2015-01-01
A comprehensive guide to AngularJS, Google's open-source client-side framework for app development. Most of the existing guides to AngularJS struggle to provide simple and understandable explanations for more advanced concepts. As a result, some developers who understand all the basic concepts of AngularJS struggle when it comes to building more complex real-world applications. Professional AngularJS provides a thorough understanding of AngularJS, covering everything from basic concepts, such as directives and data binding, to more advanced concepts like transclusion, build systems, and auto
Energy angular momentum closed-loop guidance
Patera, Russell P.
2015-03-01
A novel guidance algorithm for launch vehicle ascent to the desired mission orbit is proposed. The algorithm uses total specific energy and orbital angular momentum as new state vector parameters. These parameters are ideally suited for the ascent guidance task, since the guidance algorithm steers the launch vehicle along a pre-flight optimal trajectory in energy angular momentum space. The guidance algorithm targets apogee, perigee, inclination and right ascension of ascending node. Computational complexities are avoided by eliminating time in the guidance computation and replacing it with angular momentum magnitude. As a result, vehicle acceleration, mass, thrust, length of motor burns, and staging times are also eliminated from the pitch plane guidance calculations. The algorithm does not involve launch vehicle or target state propagation, which results in minimal computational effort. Proof of concept of the new algorithm is presented using several numerical examples that illustrate performance results.
The mass and angular momentum of reconstructed metric perturbations
van de Meent, Maarten
2017-06-01
We prove a key result regarding the mass and angular momentum content of linear vacuum perturbations of the Kerr metric obtained through the formalism developed by Chrzarnowski, Cohen, and Kegeles (CCK). More precisely, we prove that the Abbott-Deser mass and angular momentum integrals of any such perturbation vanish when that perturbation was obtained from a regular Fourier mode of the Hertz potential. As a corollary we obtain a generalization of previous results on the completion of the ‘no string’ radiation gauge metric perturbation generated by a point particle. We find that for any bound orbit around a Kerr black hole, the mass and angular momentum perturbations completing the CCK metric are simply the energy and angular momentum of the particle ‘outside’ the orbit and vanish ‘inside’ the orbit.
Transverse angular momentum in topological photonic crystals
Deng, Wei-Min; Chen, Xiao-Dong; Zhao, Fu-Li; Dong, Jian-Wen
2018-01-01
Engineering local angular momentum of structured light fields in real space enables applications in many fields, in particular, the realization of unidirectional robust transport in topological photonic crystals with a non-trivial Berry vortex in momentum space. Here, we show transverse angular momentum modes in silicon topological photonic crystals when considering transverse electric polarization. Excited by a chiral external source with either transverse spin angular momentum or transverse phase vortex, robust light flow propagating along opposite directions is observed in several kinds of sharp-turn interfaces between two topologically-distinct silicon photonic crystals. A transverse orbital angular momentum mode with alternating phase vortex exists at the boundary of two such photonic crystals. In addition, unidirectional transport is robust to the working frequency even when the ring size or location of the pseudo-spin source varies in a certain range, leading to the superiority of the broadband photonic device. These findings enable one to make use of transverse angular momentum, a kind of degree of freedom, to achieve unidirectional robust transport in the telecom region and other potential applications in integrated photonic circuits, such as on-chip robust delay lines.
SPL Division
2001-01-01
Stores users are informed that the Stores (Central, Emergency window, Raw materials, Chemical products and Prévessin Self service stores) will be closed on Friday, 7 December owing to migration of the Stores computers to Windows 2000. Thank you for your understanding.
Diffracted optical vortices by an angular aperture
López H., Paula A.; Reyes Q., Zayda P.; Guzmán, Ángela M.; Torres M., Yezid; Mendoza C., Jesús H.
2017-08-01
The measurement of the topological charge of laser beams with orbital angular momentum (OAM) is key to many applications like deciphering information encoded in several channels. Current techniques useful for that purpose are interferometry, diffraction through different poligonal apertures like triangular or pentagonal and, azimuthal and radial decomposition. A less explored issue is the diffraction of OAM beams through circular sectors. Jack et al. studied the angular diffraction of Gaussian beams (whose OAM is null) through a circular sector. By means of a Fourier transform of the truncated Gaussian beam they showed that the orbital angular momentum spectrum of the transmitted beam has a sinc-shaped envelope centered at zero orbital angular momentum, the width of which increases as the central angle of the circular sector decreases. We analyze here the spectrum of a laser beam with integer OAM that has been diffracted by a circular sector. We present results for circular sectors of different central angles. For circular π-sector, we also study the influence of the transmittance in the OAM spectra of the transmitted beam, using straight borders of nanometric thin films of titanium oxide with different thicknesses. We use a spatial light modulator with a fork hologram placed on to generate the incoming OAM beam and measure the evolution of the intensity profile of the diffracted beam as it propagates away from the circular sector. The spectra of the diffracted OAM beams are shown numerically and experimentally to have a sinc shaped envelope centered at the OAM value of the incoming OAM wave.
Parker, G. W.
1978-01-01
Discusses, classically and quantum mechanically, the angular momentum induced in the bound motion of an electron by an external magnetic field. Calculates the current density and its magnetic moment, and then uses two methods to solve the first-order perturbation theory equation for the required eigenfunction. (Author/GA)
Where angular momentum goes in a precessing black hole binary
Lousto, Carlos O.; Zlochower, Yosef
2013-01-01
We evolve a set of 32 equal-mass black-hole binaries with collinear spins (with intrinsic spin magnitudes $|\\vec{S}_{1,2}/m^2_{1,2}|=0.8$) to study the effects of precession in the highly nonlinear plunge and merger regimes. We compare the direction of the instantaneous radiated angular momentum, $\\hat{\\delta J}_{\\rm rad}(t)$, to the directions of the total angular momentum, $\\hat{J}(t)$, and the orbital angular momentum, $\\hat{L}(t)$. We find that $\\hat{\\delta J}_{\\rm rad}(t)$ approximately ...
Quantum Heuristics of Angular Momentum
Levy-Leblond, Jean-Marc
1976-01-01
Discusses the quantization of angular momentum components, Heisenberg-type inequalities for their spectral dispersions, and the quantization of the angular momentum modulus, without using operators or commutation relations. (MLH)
Quantum entanglement of high angular momenta.
Fickler, Robert; Lapkiewicz, Radek; Plick, William N; Krenn, Mario; Schaeff, Christoph; Ramelow, Sven; Zeilinger, Anton
2012-11-02
Single photons with helical phase structures may carry a quantized amount of orbital angular momentum (OAM), and their entanglement is important for quantum information science and fundamental tests of quantum theory. Because there is no theoretical upper limit on how many quanta of OAM a single photon can carry, it is possible to create entanglement between two particles with an arbitrarily high difference in quantum number. By transferring polarization entanglement to OAM with an interferometric scheme, we generate and verify entanglement between two photons differing by 600 in quantum number. The only restrictive factors toward higher numbers are current technical limitations. We also experimentally demonstrate that the entanglement of very high OAM can improve the sensitivity of angular resolution in remote sensing.
Vanston, Alex
2013-01-01
This book uses a practical, step-by-step approach, starting with how to build directives from the ground up before moving on to creating web applications comprised of multiple modules all working together to provide the best user experience possible.This book is intended for intermediate JavaScript developers who are looking to enhance their understanding of single-page web application development with a focus on AngularJS and the JavaScript MVC frameworks.It is expected that readers will understand basic JavaScript patterns and idioms and can recognize JSON formatted data.
Obtaining the Electron Angular Momentum Coupling Spectroscopic Terms, jj
Orofino, Hugo; Faria, Roberto B.
2010-01-01
A systematic procedure is developed to obtain the electron angular momentum coupling (jj) spectroscopic terms, which is based on building microstates in which each individual electron is placed in a different m[subscript j] "orbital". This approach is similar to that used to obtain the spectroscopic terms under the Russell-Saunders (LS) coupling…
Directory of Open Access Journals (Sweden)
L. G. Balázs
2012-01-01
Full Text Available We studied the complete randomness of the angular distribution of BATSE gamma-ray bursts (GRBs. Based on their durations and peak fluxes, we divided the BATSE sample into 5 subsamples (short1, short2, intermediate, long1, long2 and studied the angular distributions separately. We used three methods to search for non-randomness in the subsamples: Voronoi tesselation, minimal spanning tree, and multifractal spectra. To study any non-randomness in the subsamples we defined 13 test-variables (9 from Voronoi tesselation, 3 from the minimal spanning tree and one from the multifractal spectrum. We made Monte Carlo simulations taking into account the BATSE’s sky-exposure function. We tested therandomness by introducing squared Euclidean distances in the parameter space of the test-variables. We recognized that the short1, short2 groups deviate significantly (99.90%, 99.98% from the fully random case in the distribution of the squared Euclidean distances but this is not true for the long samples. In the intermediate group, the squared Euclidean distances also give significant deviation (98.51%.
Jensen, Pablo; Boisson, Jean; Larralde, Hernán
2005-06-01
We propose a simple model to understand the economic factors that induce aggregation of some businesses over small geographical regions. The model incorporates price competition with neighboring stores, transportation costs and the satisfaction probability of finding the desired product. We show that aggregation is more likely for stores selling expensive products and/or stores carrying only a fraction of the business variety. We illustrate our model with empirical data collected in the city of Lyon.
Logistics Group
2004-01-01
As the FARNELL Catalogue CAPACITORS, RESISTORS and POTENTIOMETERS have now been integrated into the CERN Stores Catalogue (SCEM Groups 10 and 11) they can now be obtained via an EDH 'Material Request' like any other Stores item. N.B. The Farnell 'Order code' is one of the key-words that make it easier to find items in the Stores Catalogue. Logistics Group FI Department
Orbitally excited charm - strange mesons
Energy Technology Data Exchange (ETDEWEB)
Kasper, Penelope A. [Illinois Inst. of Technology, Chicago, IL (United States)
1996-05-01
This thesis describes an attempt to measure the properties of mesons containing a charm quark and a strange quark in a state of orbital angular momentum L > 0, and compare these with the predictions of theoretical models based on heavy quark effective theory.
Predicting Commissary Store Success
2014-12-01
existence and purpose of commissary stores, establishment and disestablishment criteria, store size and authorized merchandise and prices. Chapter 54...to them were cleanliness, product selection, courtesy of employees and crowding. Shoppers who frequented traditional supermarkets valued cleanliness...product selection, price competitiveness, crowding and courtesy of employees, in that order. The study found that patronage of supermarkets
2005-01-01
The Farnell catalogue can now be accessed from the Material Request form on EDH in addition to the CERN Stores catalogue. Users can order Farnell equipment as well as standard Stores equipment at the same time using a single document, the EDH Materials Request form. The Materials Request form offers users items from both the internal 'Stores' catalogue and the external 'Farnell' catalogue, all of which may be ordered on the same form. The system automatically forwards orders for standard Stores equipment to the CERN Stores and those for Farnell equipment to Farnell. The delivery time is 48 hours in both cases. Requests for materials are routed for approval in accordance with the standard EDH routing procedures. Logistics Group FI Department
2007-01-01
From next week, the SFS UNIMARKET (tooling) catalogue will be accessible using the Material Request form on EDH in addition to the CERN Stores catalogue and those of existing suppliers. Users will now be able to place orders from the SFS catalogue using the Material Request form on EDH. Note: The system automatically forwards orders for standard Stores equipment and those for SFS equipment, placed using the same Material Request form, to the CERN Stores and SFS respectively. In both cases, the maximum delivery time will be 48 hours. Requests for equipment will be routed for approval in accordance with standard EDH routing procedures. Logistics Group FI Department
2007-01-01
From next week, the SFS UNIMARKET (tooling) catalogue will be accessible using the Material Request form on EDH in addition to the CERN Stores catalogue and those of existing suppliers. Users will now be able to place orders from the SFS catalogue using the Material Request form on EDH. Note: The system automatically forwards orders for standard Stores equipment and those for SFS equipment, placed using the same Material Request form, to the CERN Stores and SFS respectively. In both cases, the maximum delivery time will be 48 hours. Requests for equipment will be routed for approval in accordance with standard EDH routing procedures. Logistics Group FI Department
2006-01-01
The Radiospares Catalogue is now accessible from the Material Request page on EDH in the same way as the CERN Stores Catalogue. This means that users can order Radiospares equipment by completing an EDH Materials Request form. N.B.: The system will automatically forward orders for standard Stores equipment to the CERN Stores and those for Radiospares equipment to Radiospares. In both cases the delivery time will be a maximum of 48 hours. Requests for materials will be routed for approval in accordance with the standard EDH routing procedures. Logistics Group FI Department
Coupling a small torsional oscillator to large optical angular momentum
Shi, H.; Bhattacharya, M.
2013-03-01
We propose a new configuration for realizing torsional optomechanics: an optically trapped windmill-shaped dielectric interacting with Laguerre-Gaussian cavity modes containing both angular and radial nodes. In contrast to existing schemes, our method can couple mechanical oscillators smaller than the optical beam waist to the in-principle unlimited orbital angular momentum that can be carried by a single photon, and thus generate substantial optomechanical interactions. Combining the advantages of small mass, large coupling, and low clamping losses, our work conceptually opens the way for the observation of quantum effects in torsional optomechanics.
Spatial distribution of angular momentum inside the nucleon
Lorcé, Cédric; Mantovani, Luca; Pasquini, Barbara
2018-01-01
We discuss in detail the spatial distribution of angular momentum inside the nucleon. We show that the discrepancies between different definitions originate from terms that integrate to zero. Even though these terms can safely be dropped at the integrated level, they have to be taken into account when discussing distributions. Using the scalar diquark model, we illustrate our results and, for the first time, check explicitly that the equivalence between kinetic and canonical orbital angular momentum persists at the level of distributions, as expected in a system without gauge degrees of freedom.
Classification of Stellar Orbits Near Corotation
Breet, Jessica; Daniel, Kathryne J.; Bryn Mawr College Galaxy Lab
2018-01-01
The process of radial migration is frequently invoked as an important process to spiral galaxy evolution, but the physical properties that determine the efficiency of radial migration are poorly defined. In order for a star to migrate radially it must first be trapped in a resonant orbit at the corotation radius of a spiral pattern. Stars in such trapped orbits have changing average orbital radii — and thus orbital angular momenta — without any change in orbital eccentricity. It follows that transient spiral patterns can permanently rearrange the distribution of orbital angular momentum in the disk without kinematically heating it. It is also known that orbits can also have a significant dynamical response at Lindblad Resonances (LRs), where the Ultraharmonic Lindblad Resonances (ULRs) have a lesser impact on the disk. The goal of our project is to examine and constrain the efficiency of radial migration via an investigation into whether or not stars in trapped orbits have a dynamical response at the ULRs. We produced a dataset of nearly 105 orbits with initial conditions across a range of radii and 2-D velocities. We then classified these orbits into four categories based on analytic criteria for whether or not they are in trapped orbits and/or cross the ULR over 1 gigayear. Preliminary investigations show that trapped orbits that also meet the ULR have a chaotic response, putting a potential limit on the efficiency of radial migration.
... away from the stove, sink, and any hot appliances. You can also store medicine in a storage ... us Disclaimers Copyright Privacy Accessibility Quality Guidelines Viewers & Players MedlinePlus Connect for EHRs For Developers U.S. National ...
African Journals Online (AJOL)
user
2010-06-06
Jun 6, 2010 ... loss due to insect feeding was 0.60 g per 400 g of stored groundnuts. When ... The mean A. flavus spore concentration recovered from initially sterile .... Studies on the effectiveness of diatomaceous earths have been reported.
2006-01-01
The Bossard catalogue is now accessible alongside the CERN Stores catalogue from the Material Request form on EDH. Users will thus be able to order Bossard equipment using the EDH Materials Request form. As a reminder, the system automatically forwards orders for standard Stores equipment to the CERN Stores and those for Bossard equipment to Bossard. In both cases the delivery time will be a maximum of 48 hours. Requests for materials will be routed for approval in accordance with the standard EDH routing procedures. Some items will remain available from the emergency desk in the event of urgent requests. These items will be visible in the Stores catalogue even if they cannot be purchased via the EDH material request form. Logistics Group FI Department
Angular momentum conservation law in light-front quantum field theory
Energy Technology Data Exchange (ETDEWEB)
Chiu, Kelly Yu-Ju; Brodsky, Stanley J.; /SLAC /Stanford U.
2017-03-01
We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the light-front formulation. We explicitly show that j 3 , the z -component of the angular momentum remains unchanged under Lorentz transformations generated by the light-front kinematical boost operators. The invariance of j 3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QED and QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.
Coherent Detection of Orbital Angular Momentum in Radio
2014-08-31
measurements took place in an anechoic chamber at a frequency of 2.383 GHz (corresponding to a wave- length, λ, of 0.126 m) and at a distance of z = 4.82 m...were parallel to a chamber wall, and the z axis was perpendicular to the same wall. By feeding the transmitting antennas with equal amplitudes and...to the new Ångström Laboratory antenna chamber , which was funded by the Knut and Alice Wallenberg Founda- tion. We thank the electronics lab of the
Integrated Photonic Orbital Angular Momentum Multiplexing and Demultiplexing on Chip
2014-10-31
bit-rate DWDM submarine systems, Appendix I.9, (2004). This work was supported in part by DARPA DSO under the contracts HR0011-11-1-0005 and...Recommendations G.975.1 : Forward error correction for high bit-rate DWDM submarine systems, Appendix I.9, 2004. Un de r R ev iew > REPLACE THIS LINE WITH
Holographic toolkit for optical communication beyond orbital angular momentum
CSIR Research Space (South Africa)
Rosales-Guzman, C
2016-09-01
Full Text Available -Te´le´com/Te´le´com SudParis, 9 rue Charles Fourier, 91011 Evry, France ABSTRACT Current optical communication technologies are predicted to face a bandwidth capacity limit in the near future. The nature of the limitation is fundamental rather than technological... momentum multiplexing.,” Nat. Commun. 5, 4876 (2014). [20] Torres, J. P., “Optical communications: Multiplexing twisted light,” Nature Photonics 6(7), 420–422 (2012). [21] Zhao, N., Li, X., Li, G., and Kahn, J. M., “Capacity limits of spatially multiplexed...
Long range quasi-nondiffracting beams carrying orbital angular momentum
CSIR Research Space (South Africa)
Ismail, Y
2010-03-01
Full Text Available In this paper the authors outline an optical design for producing high-order Bessel-like beams with a z-dependent cone angle through the use of conventional optical elements, without the need for deliberate aberrations to be included....
Quantitative measurement of the orbital angular momentum density of light
CSIR Research Space (South Africa)
Dudley, Angela L
2012-03-01
Full Text Available to parti- cles in optical tweezers [2] to the entanglement of OAM in parametric downconversion [3]. Fields that carry OAM of l� per photon, some of which include Laguerre?Gaussian beams [4], Bessel?Gaussian beams [5], and Airy beams [6], have... an azimuthal an- gular dependence of exp�il?� [1,4], where l is the unbounded azimuthal mode index and ? is the azi- muthal angle. Since these fields possessing OAM offer an unbounded state space, they provide a larger bandwidth for quantum cryptography [7...
Continuous Variable Entanglement of Orbital Angular Momentum States
DEFF Research Database (Denmark)
Lassen, Mikael Østergaard; Leuchs, G.; Andersen, Ulrik Lund
2009-01-01
We have generated a new quantum state of light composed of quadrature entangled Laguerre-Gaussian (LG) modes. For the generation we used an OPO operating in a new regime where all field parameters are degenerate except for its spatial degree of freedom for which it is two-fold degenerate. The ent...
Quantitatively measuring the orbital angular momentum density of light : Presentation
CSIR Research Space (South Africa)
Dudley, Angela L
2013-08-01
Full Text Available the power and relative phase of each individual mode. Measuring the power of a specific mode requires the complex conjugate of that mode to be programmed as the transmission function [24]: ).()( * rrT ll Ψ...
Energy Technology Data Exchange (ETDEWEB)
Paulson, Patrick R.; Gibson, Tara D.; Schuchardt, Karen L.; Stephan, Eric G.
2008-03-01
Requirements for the provenance store and access API are developed. Existing RDF stores and APIs are evaluated against the requirements and performance benchmarks. The team’s conclusion is to use MySQL as a database backend, with a possible move to Oracle in the near-term future. Both Jena and Sesame’s APIs will be supported, but new code will use the Jena API
Bailey, Simon
2015-01-01
This book is intended for developers who have an understanding of the basic principles behind both AngularJS and test-driven development. You, as a developer, are interested in eliminating the fear related to either introducing tests to an existing codebase or starting out testing on a fresh AngularJS application. If you're a team leader or part of a QA team with the responsibility of ensuring full test coverage of an application, then this book is ideal for you to comprehend the full testing scope required by your developers. Whether you're new to or are well versed with AngularJS, this book
Nuclear scissors modes and hidden angular momenta
Energy Technology Data Exchange (ETDEWEB)
Balbutsev, E. B., E-mail: balbuts@theor.jinr.ru; Molodtsova, I. V. [Joint Institute for Nuclear Research (Russian Federation); Schuck, P. [Université Paris-Sud, Institut de Physique Nucléaire, IN2P3–CNRS (France)
2017-01-15
The coupled dynamics of low-lying modes and various giant resonances are studied with the help of the Wigner Function Moments method generalized to take into account spin degrees of freedom and pair correlations simultaneously. The method is based on Time-Dependent Hartree–Fock–Bogoliubov equations. The model of the harmonic oscillator including spin–orbit potential plus quadrupole–quadrupole and spin–spin interactions is considered. New low-lying spin-dependent modes are analyzed. Special attention is paid to the scissors modes. A new source of nuclear magnetism, connected with counter-rotation of spins up and down around the symmetry axis (hidden angular momenta), is discovered. Its inclusion into the theory allows one to improve substantially the agreement with experimental data in the description of energies and transition probabilities of scissors modes.
1980-01-15
enhancement when coupled with the video acquisition performed by the Frame Store Memory in mode 2. 3 -11 It cr (A 3 coJ 0( kLL P.- FAIRCHILO IMAGING ...AD-AOSI 979 FAIRCHILD IMAGING SYSTEMS SYOSSET N Y F/0 17/2 ANALOG FRAME STORE MEMORY . CU) JAN 80 OAAK77-C-0165 UNCLASSIFIED ED-CX-141-5 M 1 .0 H " 1...DESCRIPTION 1-2 1.1.1 Analog Frame Store Memory 1-2 1.1.2 Analog Field Storage Device 1-4 1.1.3 Image Analyzer Digital Display (IADD) 1-4 1.2 PROGRAM’S
2008-01-01
The DISTRELEC catalogue (IT) is now available in EDH in addition to the CERN Stores catalogue and the catalogues of existing suppliers. Using an EDH materials request form, users can now order DISTRELEC equipment from amongst the following product groups: peripherals, multimedia, PC components, data media, communication and data cables and adapters. Non-authorised materials will be clearly indicated. As a reminder, the system automatically manages the distribution of standard Stores equipment and punch out equipment ordered on the same request form. In both cases, delivery will take a maximum of 48 hours. The approval of the EDH document will follow the usual EDH routing procedures. Logistics Group FI Department
N2 HOMO-1 orbital cross section revealed through high-order-harmonic generation
Troß, Jan; Ren, Xiaoming; Makhija, Varun; Mondal, Sudipta; Kumarappan, Vinod; Trallero-Herrero, Carlos A.
2017-03-01
We measure multi-orbital contributions to high harmonic generation from aligned nitrogen. We show that the change in revival structure in the cutoff harmonics has a counterpart in the angular distribution when a lower-lying orbital contributes to the harmonic yield. This angular distribution is directly observed in the laboratory without any further deconvolution. Because of the high degree of alignment we are able to distinguish angular contributions of the highest occupied molecular orbital 1 (HOMO-1) orbital from angle-dependent spectroscopic features of the HOMO. In particular, we are able to make a direct comparison with the cross section of the HOMO-1 orbital in the extreme ultraviolet region.
Mouriaux, F; Rysanek, B; Babin, E; Cattoir, V
2012-01-01
Orbital cellulitis is uncommon in ophthalmologic practice. The majority of cases arise from direct spread of sinus infection or eyelid infection. Clinically, orbital cellulitis is divided into two forms: the preseptal form, anterior to the orbital septum, and the retroseptal form, posterior to the orbital septum. Management and prognosis differ widely between the two types. The retroseptal form or "true" orbital cellulitis is a severe disease with potentially disastrous consequences for vision and survival. Clinical examination and urgent CT scanning are indispensable for correct diagnosis, evaluation of severity, surgical planning and antibiotic selection. Copyright © 2011 Elsevier Masson SAS. All rights reserved.
DEFF Research Database (Denmark)
Åge, Jensen Niels; Leo, Holm; Mogens, Posvig
1999-01-01
A seasonal thermal storage, consisting of a pit store with gravel-sand fill and pipe heat exchanger is designed and conducted at the Central Solar Heating Plant in Marstal, Aeroe.The task, by DTU was to carrie out experiments to determine the heat transport from the polymer pipes to the storage...
Roman, Harry T.
2014-01-01
Biomedical and robotic technologies are merging to present a wonderful opportunity to develop artificial limbs and prosthetic devices for humans injured on the job, in the military, or due to disease. In this challenge, students will have the opportunity to design a store or online service that specifically dedicates itself to amputees. Described…
FI Department
2008-01-01
From the beginning of March onwards, the LYRECO (stationery) catalogue will be accessible from the Material Request form on EDH in the same way as the CERN Stores catalogue and the existing individual supplier catalogues. Items will be delivered within a maximum of 48 hours. Logistics Group FI Department
Designing and Optimizing Future Spaceborne Multi-angular, Polarimetric Sensors
Petroy, S. B.; Nicholson, R. E.; D'Entremont, R. P.; Snell, H. E.
2004-05-01
Polarimetric measurements in the visible/near-infrared spectral region improve aerosol and cloud microphysical and compositional retrievals. The retrieval approaches exploit the unique polarimetric signatures of aerosols and clouds as function of scattering angle, thereby driving the requirement for data collection over a large range of scattering angles (ideally between 0 and 180 degrees). Scattering angle coverage is a function both of the sensor/sun/target geometry and the sensor architectural approach toward acquiring multi-angular data. These two functions must be considered when designing and implementing a spaceborne, multi-angular polarimetric sensor. The orbital geometry trade is dictated by the range of possible orbits and will quickly reduce to a subset of optimal orbital scenarios. However, the desired parameter of interest (aerosols vs. clouds properties), its spatial variability, and global extent must be considered when selecting an optimal orbit. For example, while a noon-equatorial crossing-time provides the best scattering angle coverage for the retrievals, the increased presence of clouds may preclude use of much of the data for characterizing aerosols. The sensor architectural trade investigates differing sensor approaches to providing sufficient scattering angle coverage. Current polarimetric sensor designs include both the over-lapping imagery approach (e.g. POLarization and Directionality of the Earth's Reflectances - POLDER) and the single-pixel, scanning approach (e.g. Research Scanning Polarimeter - RSP). POLDER (a spaceborne sensor) traded the benefit of image data with a large swath width against the collection of simultaneous polarimetry. RSP (an airborne sensor) collects multi-angular data by scanning the air mass during over-flight with a set of polarimetric compensating mirrors. The RSP design allows for simultaneous polarimetry and potentially very large scattering angle ranges on orbit, but is restricted to a single-pixel detector
Tailoring spin-orbit torque in diluted magnetic semiconductors
Li, Hang
2013-05-16
We study the spin orbit torque arising from an intrinsic linear Dresselhaus spin-orbit coupling in a single layer III-V diluted magnetic semiconductor. We investigate the transport properties and spin torque using the linear response theory, and we report here: (1) a strong correlation exists between the angular dependence of the torque and the anisotropy of the Fermi surface; (2) the spin orbit torque depends nonlinearly on the exchange coupling. Our findings suggest the possibility to tailor the spin orbit torque magnitude and angular dependence by structural design.
Convenience Store Workplace Literacy Curriculum.
Van Duzer, Carol; Mansoor, Inaam
The Convenience Store Workplace Literacy Curriculum was developed for English-as-a-Second-Language classes offered by the Southland Corporation, 7-Eleven stores, through a national workplace literacy grant. It is based on an analysis of the tasks and interactions common to a convenience store worksite. Store employees, managers, field consultants,…
Menard, Dan
2013-01-01
Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. This book is written in an easytoread style, with a strong emphasis on realworld, practical examples. Stepbystep explanations are provided for performing important tasks.This book is for web developers familiar with JavascriptIt doesn't cover the history of AngularJS, and it's not a pitch to convince you that AngularJS is the best framework on the entire web. It's a guide to help you learn everything you need to know about AngularJS in as few pa
Escobar, Gloria; Trujillo B, Nicolas; Vélez, Maria A
2016-01-01
El presente trabajo de grado para opta al título de Administración de empresas contiene una estrategia digital de mercadeo para un negocio de bicicletas, consta de un plan y selección de medios y de todos los conocimientos aprendidos en el curso Estrategias digitales para negocios. La estrategia se trata del lanzamiento de un producto para lograr posicionamiento y ventas para la marca Naironman Store.
Store and forward teledermatology
Directory of Open Access Journals (Sweden)
Kanthraj Garehatty
2007-01-01
Full Text Available Store and forward and real time or videoconferences are the two types of teledermatology services practiced. Dermatology and radio-diagnosis are visual specialties suited for store-and-forward teledermatology (SAFT. Advances in information technology, electronic instruments and biotechnology have revolutionized and brought changes in SAFT. Cellular phone, digital camera, personal digital assistants, Wi-Fi, Wi-Max and computer- aided-design software are incorporated to deliver the quality health care to remote geographic regions. Complete SAFT care equivalent to face-to-face consultation (Gold standard is essential. Health care providers in rural areas are the ′eyes′ for the consultants. Consultants to guide them should have a rapid periodic audit of visual parameters and dimensions of lesions. Given this background, this article reviews advances in 1 capture, store and transfer of images. 2 Computer Aided measurements of generalized and localized lesions and 3 the integration model to meet all the above two requirements in a centralized location. This process enables diagnosis, management, periodic assessment and complete follow-up care to achieve patient and physician satisfaction. Preservation of privacy and confidentiality of digital images is important. Uniform rules and regulations are required. Indian space research organization (ISRO, Government of India has demonstrated telemedicine pilot projects utilizing the satellite communication and mobile telemedicine units to be useful in meeting the health care needs of remote and rural India. we have to join hands with them to meet dermatology problems in rural areas.
Non-Colinearity of Angular Velocity and Angular Momentum
Burr, A. F.
1974-01-01
Discusses the principles, construction, and operation of an apparatus which serves to demonstrate the non-colinearity of the angular velocity and momentum vectors as well as the inertial tensors. Applications of the apparatus to teaching of advanced undergraduate mechanics courses are recommended. (CC)
Directory of Open Access Journals (Sweden)
Elliot Leader
2016-05-01
Full Text Available The claim some years ago, contrary to all textbooks, that the angular momentum of a photon (and gluon can be split in a gauge-invariant way into an orbital and spin term, sparked a major controversy in the Particle Physics community, exacerbated by the realization that many different forms of the angular momentum operators are, in principle, possible. A further cause of upset was the realization that the gluon polarization in a nucleon, a supposedly physically meaningful quantity, corresponds only to the gauge-variant gluon spin derived from Noether's theorem, evaluated in a particular gauge. On the contrary, Laser Physicists have, for decades, been happily measuring physical quantities which correspond to photon orbital and spin angular momentum evaluated in a particular gauge. This paper reconciles the two points of view, and shows that it is the gauge invariant version of the canonical angular momentum which agrees with the results of a host of laser optics experiments.
Energy Technology Data Exchange (ETDEWEB)
Leader, Elliot, E-mail: e.leader@imperial.ac.uk
2016-05-10
The claim some years ago, contrary to all textbooks, that the angular momentum of a photon (and gluon) can be split in a gauge-invariant way into an orbital and spin term, sparked a major controversy in the Particle Physics community, exacerbated by the realization that many different forms of the angular momentum operators are, in principle, possible. A further cause of upset was the realization that the gluon polarization in a nucleon, a supposedly physically meaningful quantity, corresponds only to the gauge-variant gluon spin derived from Noether's theorem, evaluated in a particular gauge. On the contrary, Laser Physicists have, for decades, been happily measuring physical quantities which correspond to photon orbital and spin angular momentum evaluated in a particular gauge. This paper reconciles the two points of view, and shows that it is the gauge invariant version of the canonical angular momentum which agrees with the results of a host of laser optics experiments.
Angular Limb Deformities: Growth Retardation.
McCarrel, Taralyn M
2017-08-01
Angular limb deformities are common in foals; however, the importance of the deformity and if treatment is required depend on the degree of deformity relative to normal conformation for stage of growth, the breed and discipline expectations, age, and response to conservative therapies. This article addresses the importance of the foal conformation examination to determine which foals need surgical intervention to correct an angular deformity and when. Techniques for surgical growth retardation include the transphyseal staple, screw and wire transphyseal bridge, and transphyseal screw. Appropriate timing for intervention for each location and complications associated with each procedure are discussed. Copyright © 2017 Elsevier Inc. All rights reserved.
Satellite orbits in Levi-Civita space
Humi, Mayer
2018-03-01
In this paper we consider satellite orbits in central force field with quadratic drag using two formalisms. The first using polar coordinates in which the satellite angular momentum plays a dominant role. The second is in Levi-Civita coordinates in which the energy plays a central role. We then merge these two formalisms by introducing polar coordinates in Levi-Civita space and derive a new equation for satellite orbits which unifies these two paradigms. In this equation energy and angular momentum appear on equal footing and thus characterize the orbit by its two invariants. Using this formalism we show that equatorial orbits around oblate spheroids can be expressed analytically in terms of Elliptic functions. In the second part of the paper we derive in Levi-Civita coordinates a linearized equation for the relative motion of two spacecrafts whose trajectories are in the same plane. We carry out also a numerical verification of these equations.
African Journals Online (AJOL)
Aim: The purpose of this study was to assess the prevalence of paranasal sinusitis as a cause of orbital cellulitis and to identify the commonest sinus(es) involved in our setting. Methods: A retrospective review of the case notes of 47 patients with orbital cellulitis admitted into the ophthalmic ward of the University College ...
Modestino, Giuseppina
2016-01-01
The trajectory and the orbital velocity are determined for an object moving in a gravitational system, in terms of fundamental and independent variables. In particular, considering a path on equipotential line, the elliptical orbit is naturally traced, verifying evidently the keplerian laws. The case of the planets of the solar system is presented.
DEFF Research Database (Denmark)
Zielke, Stephan
2014-01-01
This paper analyzes the impact of price-related attributions, emotions and value perception on the intention to shop at grocery discounters in an integrated framework. Moderating effects of price consciousness are also analyzed. The results show that the proposed model explains almost three...... quarters of intentions to shop in discount stores. Value perception has the strongest total effect, which is partly mediated by enjoyment, shame and guilt. Attributions influence the shopping intention indirectly via value perception and emotions. The inferior quality attribution has the strongest total...
Angular momentum exchange in white dwarf binaries accreting through direct impact
Energy Technology Data Exchange (ETDEWEB)
Sepinsky, J. F. [Department of Physics and Electrical Engineering, The University of Scranton, Scranton, PA 18510 (United States); Kalogera, V., E-mail: jeremy.sepinsky@scranton.edu, E-mail: vicky@northwestern.edu [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States)
2014-04-20
We examine the exchange of angular momentum between the component spins and the orbit in semi-detached double white dwarf binaries undergoing mass transfer through direct impact of the transfer stream. We approximate the stream as a series of discrete massive particles ejected in the ballistic limit at the inner Lagrangian point of the donor toward the accretor. This work improves upon similar earlier studies in a number of ways. First, we self-consistently calculate the total angular momentum of the orbit at all times. This includes changes in the orbital angular momentum during the ballistic trajectory of the ejected mass, as well as changes during the ejection/accretion due to the radial component of the particle's velocity. Second, we calculate the particle's ballistic trajectory for each system, which allows us to determine the precise position and velocity of the particle upon accretion. We can then include specific information about the radius of the accretor as well as the angle of impact. Finally, we ensure that the total angular momentum is conserved, which requires the donor star spin to vary self-consistently. With these improvements, we calculate the angular momentum change of the orbit and each binary component across the entire parameter space of direct impact double white dwarf binary systems. We find a significant decrease in the amount of angular momentum removed from the orbit during mass transfer, as well as cases where this process increases the angular momentum of the orbit at the expense of the spin angular momentum of the donor. We conclude that, unlike earlier claims in the literature, mass transfer through direct impact need not destabilize the binary and that the quantity and sign of the orbital angular momentum transfer depends on the binary properties, particularly the masses of the double white dwarf binary component stars. This stabilization may significantly impact the population synthesis calculations of the expected
MOOSE: Manned On-Orbit Servicing Equipment
Budinoff, J.; Leontsinis, N.; Lane, J.; Singh, R.; Angelone, K.; Boswell, C.; Chamberlain, I.; Concha, M.; Corrodo, M.; Custodio, O.
The ability to service satellites has thus far been limited to low earth orbit platforms within reach of the Space Shuttle. Other orbits, such as geosynchronous orbits containing high-value spacecraft have not been attainable by a servicing vehicle. The useful life of a satellite can be extended by replacing spent propellant and damaged orbital replacement units, forestalling the need for eventual replacement. This growing need for satellite on-orbits servicing can be met by the Manned On-Orbit Servicing Equipment (MOOSE). Missions requiring orbit transfer capability, precision manipulation and maneuvering, and man-in-the-loop control can be accomplished using MOOSE. MOOSE is a flexible, reusable, single operator, aerobraking spacecraft designed to refuel, repair, and service orbiting spacecraft. MOOSE will be deployed from Space Station Freedom, (SSF), where it will be stored, resupplied, and refurbished.
The Hot Orbit: Orbital Cellulitis
Chaudhry, Imtiaz A.; Al-Rashed, Waleed; Arat, Yonca O.
2012-01-01
Orbital cellulitis is an uncommon condition previously associated with severe complications. If untreated, orbital cellulitis can be potentially sight and life threatening. It can affect both adults and children but has a greater tendency to occur in the pediatric age group. The infection most commonly originates from sinuses, eyelids or face, retained foreign bodies, or distant soources by hematogenous spread. It is characterized by eyelid edema, erythema, chemosis, proptosis, blurred vision, fever, headache, and double vision. A history of upper respiratory tract infection prior to the onset is very common especially in children. In the era prior to antibiotics, vision loss from orbital cellulitis was a dreaded complication. Currently, imaging studies for detection of orbital abcess, the use of antibiotics and early drainage have mitigated visual morbidity significantly. The purpose of this review is to describe current investigative strategies and management options in the treatment of orbital cellulitis, establish their effectiveness and possible complications due to late intervention. PMID:22346113
Netemeyer, Richard G; Maxham, James G; Lichtenstein, Donald R
2010-05-01
Based on emotional contagion theory and the value-profit chain literatures, the present study posits a number of hypotheses that show how managers in the small store, small number of employees retail context may affect store employees, customers, and potentially store performance. With data from 306 store managers, 1,615 store customer-contact employees, and 57,656 customers of a single retail chain, the authors examined relationships among store manager job satisfaction and job performance, store customer-contact employee job satisfaction and job performance, customer satisfaction with the retailer, and a customer-spending-based store performance metric (customer spending growth over a 2-year period). Via path analysis, several hypothesized direct and interaction relations among these constructs are supported. The results suggest implications for academic researchers and retail managers. PsycINFO Database Record (c) 2010 APA, all rights reserved.
DEFF Research Database (Denmark)
Yazdanfard, Younes; Heegard, Steffen; Fledelius, Hans C.
2001-01-01
Ophthalmology, penetrating orbital injury, orbital foreign body, ultrasound, computed tomography (CT), histology......Ophthalmology, penetrating orbital injury, orbital foreign body, ultrasound, computed tomography (CT), histology...
Angular momentum in QGP holography
Directory of Open Access Journals (Sweden)
Brett McInnes
2014-10-01
Full Text Available The quark chemical potential is one of the fundamental parameters describing the quark–gluon plasma produced by sufficiently energetic heavy-ion collisions. It is not large at the extremely high temperatures probed by the LHC, but it plays a key role in discussions of the beam energy scan programmes at the RHIC and other facilities. On the other hand, collisions at such energies typically (that is, in peripheral collisions give rise to very high values of the angular momentum density. Here we explain that holographic estimates of the quark chemical potential of a rotating sample of plasma can be very considerably improved by taking the angular momentum into account.
Geostationary Orbit Surveillance Using the Unscented Kalman Filter and the Analytical Orbit Model
Directory of Open Access Journals (Sweden)
Kyoung-Min Roh
2011-09-01
Full Text Available A strategy for geostationary orbit (or geostationary earth orbit [GEO] surveillance based on optical angular observations is presented in this study. For the dynamic model, precise analytical orbit model developed by Lee et al. (1997 is used to improve computation performance and the unscented Kalman filer (UKF is applied as a real-time filtering method. The UKF is known to perform well under highly nonlinear conditions such as surveillance in this study. The strategy that combines the analytical orbit propagation model and the UKF is tested for various conditions like different level of initial error and different level of measurement noise. The dependencies on observation interval and number of ground station are also tested. The test results shows that the GEO orbit determination based on the UKF and the analytical orbit model can be applied to GEO orbit tracking and surveillance effectively.
AngularJS test-driven development
Chaplin, Tim
2015-01-01
This book is for developers who want to learn about AngularJS development by applying testing techniques. You are assumed to have a basic knowledge and understanding of HTML, JavaScript, and AngularJS.
The importance of store windows in creating store identity and store attractiveness
Directory of Open Access Journals (Sweden)
Renko Sanda
2012-01-01
Full Text Available While choosing the store, customer first notices the store window and it plays an important role in retailing strategy. Store's window is what customers see first in meeting with the store. Store window design can lead customer to enter the store, and can give a lot of information about store brands and products. Besides the analysis of the way how specific elements of the window design affect customers and their perception, the explanation of their attraction and rejection to customers is given. If we consider the importance of the topics, we can point out the lack of literature about store windows as the communication tool which allow store to communicate with its customers and to create its retailing strategy as well. There is the scientific contribution of this paper. The paper gives theoretical comprehensions completed with the results of the study about the importance of store windows for retailers as well as for customers. Therefore, for the purpose of this paper, a two-phase research study, including a qualitative and a quantitative approach, was used: 1 the qualitative study among retailers which indicated the most important elements of store windows, the level of financial sources invested in the window design, the basis for the decisions about store window design, etc.; 2 the quantitative study on the sample of consumers conducted with on-line questionnaire. Findings suggest that store window attractiveness is the main motif for store visits. The results of the research confirm that by means of store window and its elements (with special emphasis on price and pricing actions retail store sends messages to its consumers.
AngularJS web application development
Darwin, Peter Bacon
2013-01-01
The book will be a step-by-step guide showing the readers how to build a complete web app with AngularJSJavaScript developers who want to learn AngularJS for developing web apps. Knowledge of JavaScript and HTML is expected. No knowledge of AngularJS is required.
C-store: storing relational data by columns
Částek, Petr
2009-01-01
Non standard approach to the implementation of relational databases this work implements a database system storing the data by columns instead of rows. It is based on the C Store system design and is limited only to the fundamental solution issues. Two areas are being solved: the initial creation of the database, including import of static database data from another source, and querying. The database does not store the data in tables but in projections groups of columns of the same length. By...
The role of angular momentum conservation law in statistical mechanics
Directory of Open Access Journals (Sweden)
I.M. Dubrovskii
2008-12-01
Full Text Available Within the limits of Khinchin ideas [A.Y. Khinchin, Mathematical Foundation of Statistical Mechanics. NY, Ed. Dover, 1949] the importance of momentum and angular momentum conservation laws was analyzed for two cases: for uniform magnetic field and when magnetic field is absent. The law of momentum conservation does not change the density of probability distribution in both cases, just as it is assumed in the conventional theory. It is shown that in systems where the kinetic energy depends only on particle momenta canonically conjugated with Cartesian coordinates being their diagonal quadric form,the angular momentum conservation law changes the density of distribution of the system only in case the full angular momentum of a system is not equal to zero. In the gas of charged particles in a uniform magnetic field the density of distribution also varies if the angular momentum is zero [see Dubrovskii I.M., Condensed Matter Physics, 2206, 9, 23]. Two-dimensional gas of charged particles located within a section of an endless strip filled with gas in magnetic field is considered. Under such conditions the angular momentum is not conserved. Directional particle flows take place close to the strip boundaries, and, as a consequence, the phase trajectory of the considered set of particles does not remain within the limited volume of the phase space. In order to apply a statistical thermodynamics method, it was suggested to consider near-boundary trajectories relative to a reference system that moves uniformly. It was shown that if the diameter of an orbit having average thermal energy is much smaller than a strip width, the corrections to thermodynamic functions are small depending on magnetic field. Only the average velocity of near-boundary particles that form near-boundary electric currents creating the paramagnetic moment turn out to be essential.
Dependency injection with AngularJS
Knol, Alex
2013-01-01
This book is a practical, hands-on approach to using dependency injection and implementing test-driven development using AngularJS. Dependency Injection with AngularJS is aimed at developers who are aware of AngularJS but need to get started with using it in real life applications. Also, developers who want to get into test-driven development with AngularJS can use this book as practical guide. Even if you know about dependency injection, it can serve as a good reference on how it is used within AngularJS. Readers are expected to have some experience with JavaScript.
A theory of thin shells with orbiting constituents
Berezin, V A; Berezin, Victor; Okhrimenko, Maxim
2001-01-01
The self-gravitating, spherically symmetric thin shells built of orbiting particles are sstudied. Two new features are found. One is the minimal possible value for an angular momentum of particles, above which elleptic orbits become possible. The second is the coexistence of both the wormhole solutions and the elleptic or hyperbolic orbits for the same values of the parameters (but different initial conditions). Possible applications of these results to astrophysics and quantum black holes are briefly discussed.
DEFF Research Database (Denmark)
Chen, Yunzhong; Sun, J.R.; Zhao, T.Y.
2009-01-01
The temperature and magnetic field dependence of angular dependent magnetoresistance (AMR) along two orthogonal directions ([100] and [01]) was investigated in a charge-orbital-ordered Sm0.5Ca0.5MnO3 (SCMO) film grown on (011)-oriented SrTiO3 substrates. A dramatic decrease of AMR magnitude in bo...
DEFF Research Database (Denmark)
Michelsen, Jimmi
2017-01-01
Tekstgennemgang og undervisningsforløb til Dorte Nors "Den store tomat". Undervisningsforløbet er henvendt til elever i folkeskolens udskoling......Tekstgennemgang og undervisningsforløb til Dorte Nors "Den store tomat". Undervisningsforløbet er henvendt til elever i folkeskolens udskoling...
Sośnica, Krzysztof; Prange, Lars; Kaźmierski, Kamil; Bury, Grzegorz; Drożdżewski, Mateusz; Zajdel, Radosław; Hadas, Tomasz
2017-07-01
The space segment of the European Global Navigation Satellite System (GNSS) Galileo consists of In-Orbit Validation (IOV) and Full Operational Capability (FOC) spacecraft. The first pair of FOC satellites was launched into an incorrect, highly eccentric orbital plane with a lower than nominal inclination angle. All Galileo satellites are equipped with satellite laser ranging (SLR) retroreflectors which allow, for example, for the assessment of the orbit quality or for the SLR-GNSS co-location in space. The number of SLR observations to Galileo satellites has been continuously increasing thanks to a series of intensive campaigns devoted to SLR tracking of GNSS satellites initiated by the International Laser Ranging Service. This paper assesses systematic effects and quality of Galileo orbits using SLR data with a main focus on Galileo satellites launched into incorrect orbits. We compare the SLR observations with respect to microwave-based Galileo orbits generated by the Center for Orbit Determination in Europe (CODE) in the framework of the International GNSS Service Multi-GNSS Experiment for the period 2014.0-2016.5. We analyze the SLR signature effect, which is characterized by the dependency of SLR residuals with respect to various incidence angles of laser beams for stations equipped with single-photon and multi-photon detectors. Surprisingly, the CODE orbit quality of satellites in the incorrect orbital planes is not worse than that of nominal FOC and IOV orbits. The RMS of SLR residuals is even lower by 5.0 and 1.5 mm for satellites in the incorrect orbital planes than for FOC and IOV satellites, respectively. The mean SLR offsets equal -44.9, -35.0 , and -22.4 mm for IOV, FOC, and satellites in the incorrect orbital plane. Finally, we found that the empirical orbit models, which were originally designed for precise orbit determination of GNSS satellites in circular orbits, provide fully appropriate results also for highly eccentric orbits with variable
Daniel, Kathryne J.; Wyse, Rosemary F. G.
2018-01-01
The orbital angular momentum of individual stars in galactic discs can be permanently changed through torques from transient spiral patterns. Interactions at the corotation resonance dominate these changes and have the further property of conserving orbital circularity. We derived in an earlier paper an analytic criterion that an unperturbed stellar orbit must satisfy in order for such an interaction to occur i.e. for it to be in a trapped orbit around corotation. We here use this criterion in an investigation of how the efficiency of induced radial migration for a population of disc stars varies with the angular momentum distribution of that population. We frame our results in terms of the velocity dispersion of the population, this being an easier observable than is the angular momentum distribution. Specifically, we investigate how the fraction of stars in trapped orbits at corotation varies with the velocity dispersion of the population, for a system with an assumed flat rotation curve. Our analytic results agree with the finding from simulations that radial migration is less effective in populations with `hotter' kinematics. We further quantify the dependence of this trapped fraction on the strength of the spiral pattern, finding a higher trapped fraction for higher amplitude perturbations.
Has Nemesis' orbit been detected?
Delsemme, A. H.
1986-01-01
The orbital angular momenta of 126 very young comets are calculated from the orbital data of Marsden and Roemer (1982) and analyzed statistically. A large anisotropy is detected in a plane almost perpendicular to the ecliptic and shown to have a characteristic dissipation lifetime of 10-30 Myr. Dynamic evolution computations indicate that the impulse which produced the anisotropy is that of a very slow massive (10-90 Jupiter mass) body, which is bound to the solar system, passed its 15,000-35,000-AU perihelion about 2-15 Myr ago, and has period 5-50 Myr. It is suggested that this body could well be identical to Nemesis, the object proposed to explain mass faunal extinctions.
Canadian Meteor Orbit Radar (CMOR
Directory of Open Access Journals (Sweden)
A. R. Webster
2004-01-01
Full Text Available The radar system described here (CMOR comprises a basic 5-element receiving system, co-located with a pulsed transmitter, specifically designed to observe meteor echoes and to determine their position in space with an angular resolution of ~1° and a radial resolution of ~3 km. Two secondary receiving sites, a few km distant and arranged to form approximately a right angle with the base station, allow the determination of the velocity (speed and direction of the meteor that, together with the time of occurrence, lead to an estimate of the orbit of the original meteoroid. Some equipment details are presented along with a method used to determine the orbits. Representative echoes are shown and observations on the 2002 Leonid shower presented.
An onboard star catalog for satellite angular attitude estimation
Kruzhilov, Ivan; Chernetsov, Andrey; Zakharov, Andrei; Kruzhilov, Svyatoslav
2017-09-01
Accuracy assessment of the satellite remote sensing depends on the angular attitude estimation precision. The 1 arc second error in attitude estimation causes 2.5-meter error in the accuracy derived from remote sensing data for the 500 km orbit. Different kind of momentum wheels, propulsions and sensors help correct spacecraft torque moment to stabilize it in the orbit. Star tracker is the most precise optical sensor for spacecraft angular attitude estimation. An onboard guide star catalog containing data for star pattern identification is essential for star tracker operating. The total number of stars, the faintest stellar magnitude, completeness and uniformity are the key specifications of a star catalog influencing many characteristic of a star tracker. The steps of creating guide star catalog are: instrumental stellar magnitude estimation with respect to the star tracker spectral response, clusterization of nearby stars, removing of unreliable stars and final star selection. An iterative algorithm for thinning down the catalog allows reducing appreciably the number of stars in the catalog and improving its uniformity. The key point of the algorithm is the lower bound evaluation of star number in the FOV (field of view) for every boresight position within a triangle area. The algorithm uses recursive quaternary division of the icosahedron for the celestial sphere tessellation. The correction methods of stellar aberration and star proper motion are discussed as well.
Management of angular cheilitis for children
Directory of Open Access Journals (Sweden)
Fajriani Fajriani
2016-06-01
Full Text Available Angular cheilitis is one type of oral soft tissue disease that can occur in both children and adults, the condition is characterized by cracks and inflammation in both corners of the mouth. Although this disease does not cause severe disruption but quite disturbing activity and also one's physical appearance. Angular cheilitis light will disappear on their own over time.Severe conditions that can cause pain and bleading. aims to give feedback on peers about managment angular cheilitis in children.
Directory of Open Access Journals (Sweden)
A. M. Stewart
2011-01-01
Full Text Available We compare three attempts that have been made to decompose the angular momentum of the electromagnetic field into components of an “orbital” and “spin” nature. All three expressions are different, and there seems to be no reason to prefer one to another. It appears, on the basis of classical electrodynamics, that there is no unique way of decomposing the angular momentum of the electromagnetic field into orbital and spin components, even in a fixed inertial frame.
... Glaucoma (Video) Macular Degeneration Additional Content Medical News Inflammation of the Orbit (Inflammatory Orbital Pseudotumor) By James ... Introduction to Eye Socket Disorders Cavernous Sinus Thrombosis Inflammation of the Orbit Orbital Cellulitis Preseptal Cellulitis Tumors ...
Allegheny County Supermarkets & Convenience Stores
Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Location information for all Supermarkets and Convenience Stores in Allegheny County was produced using the Allegheny County Fee and Permit Data for 2016.
Angular-Rate Estimation Using Quaternion Measurements
Azor, Ruth; Bar-Itzhack, Y.; Deutschmann, Julie K.; Harman, Richard R.
1998-01-01
In most spacecraft (SC) there is a need to know the SC angular rate. Precise angular rate is required for attitude determination, and a coarse rate is needed for attitude control damping. Classically, angular rate information is obtained from gyro measurements. These days, there is a tendency to build smaller, lighter and cheaper SC, therefore the inclination now is to do away with gyros and use other means and methods to determine the angular rate. The latter is also needed even in gyro equipped satellites when performing high rate maneuvers whose angular-rate is out of range of the on board gyros or in case of gyro failure. There are several ways to obtain the angular rate in a gyro-less SC. When the attitude is known, one can differentiate the attitude in whatever parameters it is given and use the kinematics equation that connects the derivative of the attitude with the satellite angular-rate and compute the latter. Since SC usually utilize vector measurements for attitude determination, the differentiation of the attitude introduces a considerable noise component in the computed angular-rate vector.
Angular momentum transfer in incomplete fusion
Indian Academy of Sciences (India)
The angular momentum of the intermediate nucleus formed in incomplete fusion was deduced from the isomeric cross-section ratio by considering the statistical de-excitation of the incompletely fused composite nucleus. The data show that incomplete fusion is associated with angular momenta slightly smaller than critical ...
Responsive web design with AngularJS
Patel, Sandeep Kumar
2014-01-01
If you are an AngularJS developer who wants to learn about responsive web application development, this book is ideal for you. Responsive Web Design with AngularJS is intended for web developers or designers with a basic knowledge of HTML, CSS, and JavaScript.
Concepts of radial and angular kinetic energies
DEFF Research Database (Denmark)
Dahl, Jens Peder; Schleich, W.P.
2002-01-01
We consider a general central-field system in D dimensions and show that the division of the kinetic energy into radial and angular parts proceeds differently in the wave-function picture and the Weyl-Wigner phase-space picture, Thus, the radial and angular kinetic energies are different quantities...
Information from the central stores
GS Department
2010-01-01
All items sold in the CERN shop (Bldg. 33) are now available in the central stores (Bldg. 73) and can be purchased on-line via EDH “Material Request” or at the “Emergency Desk” of the stores on the ground floor of Bldg. 73. These items are visible in the CERN catalogue under the “SCEM” codes beginning with 92. Department of General Infrastructure Services (GS) GS-SEM Group
Angular Momentum of Dwarf Galaxies
Butler, Kirsty M.; Obreschkow, Danail; Oh, Se-Heon
2017-01-01
We present measurements of baryonic mass {M}{{b}} and specific angular momentum (sAM) {j}{{b}} in 14 rotating dwarf Irregular (dIrr) galaxies from the LITTLE THINGS sample. These measurements, based on 21 cm kinematic data from the Very Large Array and stellar mass maps from the Spitzer Space Telescope, extend previous AM measurements by more than two orders of magnitude in {M}{{b}}. The dwarf galaxies show systematically higher {j}{{b}} values than expected from the {j}{{b}}\\propto {M}{{b}}2/3 scaling of spiral galaxies, representative of a scale-free galaxy formation scenario. This offset can be explained by decreasing baryon mass fractions {f}{{M}}={M}{{b}}/{M}{dyn} (where {M}{dyn} is the dynamical mass) with decreasing {M}{{b}} (for {M}{{b}}< {10}11 {M}⊙ ). We find that the sAM of neutral atomic hydrogen (H I) alone is about 2.5 times higher than that of the stars. The M-j relation of H I is significantly steeper than that of the stars, as a direct consequence of the systematic variation of the H I fraction with {M}{{b}}.
CORPORATE REBRANDING OF GRAMEDIA STORE (CORPORATE REBRANDING DI GRAMEDIA STORE
Directory of Open Access Journals (Sweden)
Natasha Helena Kairupan
2016-10-01
Full Text Available Abstract. The purposes of this research are to determine the stages of analysis, planning, and evaluation of corporate rebranding process of Gramedia Book Store to be Gramedia Store to rise stakeholder’s awareness. The method used is descriptive qualitative with positivism paradigm. The technique of collecting data through in-depth interview, observation, and literature study. The result of this research showed the analysis stage by analyzing the market through insights and foresights, brand audit through SWOT analysis, and identifying opportunities. The planning stage is by determine the purpose of the planning process and then determine the target audience, consist of external and internal customer. The planning of external customer by renaming and change of corporate identity, and marketing planning using communication channel (above the line and below the line. The planning of internal customer by Brand Induction, training, inspiration briefing at store, and innovation competition. The evaluation of rebranding process of Gramedia Store is having a focus group discussion with customer, media monitoring, and presentation to BOD. Keywords : Process, Corporate Rebranding, Stakeholder Awareness, Corporate Identity, Gramedia Store Abstrak.Tujuan penelitian ini adalah untuk mengetahui bagaimana tahapan analisis, perencanaan, dan evaluasi proses corporate rebranding Gramedia Book Store menjadi Gramedia Store untuk meningkatkan stakeholder awareness. Pendekatan yang digunakan adalah kualitatif dengan paradigma positivisme dan jenis studi deksriptif. Teknik pengumpulan data yang dilakukan melalui wawancara mendalam, observasi, dan studi pustaka. Berdasarkan hasil penelitian, tahapan analisis dilakukan dengan menganalisis pasar melalui insights dan foresights, audit merek dengan analisis SWOT, dan mengidentifikasi peluang. Dalam tahapan perencanaan dengan menentukan tujuan kemudian menentukan target audiens, yaitu eksternal dan internal. Perencanaan
Numerical simulation of orbiting black holes.
Brügmann, Bernd; Tichy, Wolfgang; Jansen, Nina
2004-05-28
We present numerical simulations of binary black hole systems which for the first time last for about one orbital period for close but still separate black holes as indicated by the absence of a common apparent horizon. An important part of the method is the construction of comoving coordinates, in which both the angular and the radial motion are minimized through a dynamically adjusted shift condition. We use fixed mesh refinement for computational efficiency.
Angular momentum conservation for dynamical black holes
Hayward, Sean A.
2006-01-01
Angular momentum can be defined by rearranging the Komar surface integral in terms of a twist form, encoding the twisting around of space-time due to a rotating mass, and an axial vector. If the axial vector is a coordinate vector and has vanishing transverse divergence, it can be uniquely specified under certain generic conditions. Along a trapping horizon, a conservation law expresses the rate of change of angular momentum of a general black hole in terms of angular momentum densities of ma...
Analysis of angular reading distortions of photographic images.
Codarin, Gabriela F; Felicio, Lilian R; Coelho, Daniel M; Oliveira, Anamaria S
2012-01-01
Although photogrammetry is a widespread technique in the health field, despite of the methodological efforts distortions in the angular readings of the images are common. To measure the error of angular measurements in photo images with different digital resolutions in an object with pre-determined angles. We used a rubber ball with 52 cm in circumference. The object was previously marked with angles of 10°, 30°, 60° and 90° degrees. The photographic records were performed with the focal axis of the camera perpendicular and three meters away from the object, without the use of optical zoom and a resolution of 3, 5 and 10 Megapixels (Mp). All photographic records were stored and a previously trained experimenter using the computer program ImageJ analyzed the angular values of each photo. The measurements were performed twice within a fifteen-days interval. Subsequently, we calculated the accuracy, relative error and error in degrees values, precision and the Intraclass Correlation Coefficient (ICC). When analyzing the angle of 10°, the average accuracy of measurements was higher for those records of 3 Mp resolution compared to 5 and 10 Mp resolutions. The ICC was considered excellent for all resolutions. With regards to the analyzed angles in photographic records, it was possible to verify that the 90-degree angle photographs were more accurate, had lower relative error and error in degrees, and were more precise, regardless of image resolution. The photographs records that were taken with a 3 Mp resolution provided great accuracy and precision measurements and lower errors values, suggesting to be the proper resolution to generate image of angles of 10º and 30º.
Patterns of store patronage in urban China
National Research Council Canada - National Science Library
Uncles, Mark D; Kwok, Simon
2009-01-01
Reported is a formal investigation of store patronage in urban China. Using consumer panel data for sales of packaged goods through store types and named store chains, patterns of sales, loyalty and duplication are examined...
Photometric Studies of Orbital Debris at GEO
Seitzer, Patrick; Abercromby, Kira J.; Rodriguez-Cowardin, Heather M.; Barker, Ed; Foreman, Gary; Horstman, Matt
2009-01-01
We report on optical observations of debris at geosynchronous Earth orbit (GEO) using two telescopes simultaneously at the Cerro Tololo Inter-American Observatory (CTIO) in Chile. The University of Michigan s 0.6/0.9-m Schmidt telescope MODEST (for Michigan Orbital DEbris Survey Telescope) was used in survey mode to find objects that potentially could be at GEO. Because GEO objects only appear in this telescope s field of view for an average of 5 minutes, a full six-parameter orbit can not be determined. Interrupting the survey for follow-up observations leads to incompleteness in the survey results. Instead, as objects are detected with MODEST, initial predictions assuming a circular orbit are done for where the object will be for the next hour, and the objects are reacquired as quickly as possible on the CTIO 0.9-m telescope. This second telescope follows-up during the first night and, if possible, over several more nights to obtain the maximum time arc possible, and the best six parameter orbit. Our goal is to obtain an initial orbit and calibrated colors for all detected objects fainter than R = 15th in order to estimate the orbital distribution of objects selected on the basis of two observational criteria: magnitude and angular rate. One objective is to estimate what fraction of objects selected on the basis of angular rate are not at GEO. A second objective is to obtain magnitudes and colors in standard astronomical filters (BVRI) for comparison with reflectance spectra of likely spacecraft materials.
Compton scattering of twisted light: Angular distribution and polarization of scattered photons
Stock, S.; Surzhykov, A.; Fritzsche, S.; Seipt, D.
2015-07-01
Compton scattering of twisted photons is investigated within a nonrelativistic framework using first-order perturbation theory. We formulate the problem in the density-matrix theory, which enables one to gain new insights into scattering processes of twisted particles by exploiting the symmetries of the system. In particular, we analyze how the angular distribution and polarization of the scattered photons are affected by the parameters of the initial beam such as the opening angle and the projection of orbital angular momentum. We present analytical and numerical results for the angular distribution and the polarization of Compton scattered photons for initially twisted light and compare them with the standard case of plane-wave light.
Store operations to maintain cache coherence
Energy Technology Data Exchange (ETDEWEB)
Evangelinos, Constantinos; Nair, Ravi; Ohmacht, Martin
2017-08-01
In one embodiment, a computer-implemented method includes encountering a store operation during a compile-time of a program, where the store operation is applicable to a memory line. It is determined, by a computer processor, that no cache coherence action is necessary for the store operation. A store-without-coherence-action instruction is generated for the store operation, responsive to determining that no cache coherence action is necessary. The store-without-coherence-action instruction specifies that the store operation is to be performed without a cache coherence action, and cache coherence is maintained upon execution of the store-without-coherence-action instruction.
Store operations to maintain cache coherence
Energy Technology Data Exchange (ETDEWEB)
Evangelinos, Constantinos; Nair, Ravi; Ohmacht, Martin
2017-09-12
In one embodiment, a computer-implemented method includes encountering a store operation during a compile-time of a program, where the store operation is applicable to a memory line. It is determined, by a computer processor, that no cache coherence action is necessary for the store operation. A store-without-coherence-action instruction is generated for the store operation, responsive to determining that no cache coherence action is necessary. The store-without-coherence-action instruction specifies that the store operation is to be performed without a cache coherence action, and cache coherence is maintained upon execution of the store-without-coherence-action instruction.
Radiofrequency encoded angular-resolved light scattering
DEFF Research Database (Denmark)
Buckley, Brandon W.; Akbari, Najva; Diebold, Eric D.
2015-01-01
The sensitive, specific, and label-free classification of microscopic cells and organisms is one of the outstanding problems in biology. Today, instruments such as the flow cytometer use a combination of light scatter measurements at two distinct angles to infer the size and internal complexity...... of cells at rates of more than 10,000 per second. However, by examining the entire angular light scattering spectrum it is possible to classify cells with higher resolution and specificity. Current approaches to performing these angular spectrum measurements all have significant throughput limitations...... Encoded Angular-resolved Light Scattering (REALS), this technique multiplexes angular light scattering in the radiofrequency domain, such that a single photodetector captures the entire scattering spectrum from a particle over approximately 100 discrete incident angles on a single shot basis. As a proof...
Spin O decay angular distribution for interfering mesons in electroproduction
Energy Technology Data Exchange (ETDEWEB)
Funsten, H.; Gilfoyle, G.
1994-04-01
Self analyzing meson electroproduction experiments are currently being planned for the CEBAF CLAS detector. These experiments deduce the spin polarization of outgoing unstable spin s (?)0 mesons from their decay angular distribution, W({theta},{psi}). The large angular acceptance of the CLAS detector permits kinematic tracking of a sufficient number of these events to accurately determine electroproduction amplitudes from the deduced polarization. Maximum polarization information is obtained from W({theta},{psi}) for decay into spin 0 daughters. The helicity of the decaying meson is transferred to the daughter`s relative orbital angular momentum m-projection; none is {open_quotes}absorbed{close_quotes} into daughter helicities. The decaying meson`s helicity maximally appears in W({theta},{psi}). W({theta},{psi}) for spin 0 daughters has been derived for (1) vector meson electroproduction and (2) general interfering mesons produced by incident pions. This paper derives W({theta},{psi}) for electroproduction of two interfering mesons that decay into spin 0 daughters. An application is made to the case of interfering scalar and vector mesons. The derivation is an extension of work by Schil using the general decay formalism of Martin. The expressions can be easily extended to the case of N interfering mesons since interference occurs pairwise in the observable W ({theta},{psi}), a quadratic function of the meson amplitudes. The derivation uses the virtual photon density matrix of Schil which is transformed by a meson electroproduction transition operator, T. The resulting density matrix for the interfering mesons is then converted into a corresponding statistical tensor and contracted into the efficiency tensor for spin 0 daughters.
Mastering AngularJD for .NET developers
Majid, Mohammad Wadood
2015-01-01
This book is envisioned for traditional developers and programmers who want to develop client-side applications using the AngularJS framework and ASP.NET Web API 2 with Visual Studio. .NET developers who have already built web applications or web services and who have a fundamental knowledge of HTML, JavaScript, and CSS and want to explore single-page applications will also find this guide useful. Basic knowledge of AngularJS would be helpful.
The engagement of optical angular momentum in nanoscale chirality
Andrews, David L.
2017-09-01
Wide-ranging developments in optical angular momentum have recently led to refocused attention on issues of material chirality. The connection between optical spin and circular polarization, linking to well-known and utilized probes of chirality such as circular dichroism, has prompted studies aiming to achieve enhanced means of differentiating enantiomers - molecules or particles of opposite handedness. A number of newly devised schemes for physically separating mirror-image components by optical methods have also been gaining traction, together with a developing appreciation of how the scale of physical dimensions ultimately determines any capacity to differentially select for material chirality. The scope of such enquiries has substantially widened on recognition that suitably structured, topologically charged beams of light - often known as `twisted light' or `optical vortices' can additionally convey orbital angular momentum. A case can be made that understanding the full scope and constraints upon chiroptical interactions in the nanoscale regime involves the resolution of CPT symmetry conditions governing the fundamental interactions between matter and photons. The principles provide a sound theoretical test-bed for new methodologies.
Angular distribution in the neutron-induced fission of actinides
Leong, L. S.; Tassan-Got, L.; Tarrio, D.; Audouin, L.; Paradela, C.; Duran, I.; Le Naour, C.; Altstadt, S.; Andrzejewsky, J.; Barbagallo, M.; Bécares, V.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Billowes, J.; Boccone, V.; Bosnar, D.; Brugger, M.; Calvino, F.; Calviani, M.; Cano-Ott, D.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Domingo-Pardo, C.; Dressler, R.; Dzysiuk, N.; Eleftheriadis, C.; Ferrari, A.; Fraval, K.; Ganesan, S.; García, A. R.; Giubrone, G.; Gómez-Hornillos, M. B.; Gonçalves, I. F.; González-Romero; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Gurusamy, P.; Jenkins, D. G.; Jericha, E.; Kadi, E.; Käppeler, F.; Karadimos, D.; Kivel, N.; Koehler, P.; Kokkoris, M.; Korschinek, G.; Kroll, J.; Krtička, M.; Langer, C.; Lederer, C.; Leeb, H.; Losito, R.; Manousos, A.; Marganiec, J.; Massimi, C.; Martínez, T.; Mastinu, P. F.; Mastromarco, M.; Meaze, M.; Mengon, A.; Mendoza, E.; Milazzo, P. M.; Mingrone, T.; Mirea, M.; Mondelaers, W.; Pavlik, A.; Perkowski, J.; Pignatari, M.; Plompen, A.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifhart, R.; Riego, A.; Roman, F.; Rubbia, C.; Sarmento, R.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Taín, J. L.; Tagliente, G.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Versaci, R.; Vermeulen, M. J.; Vlachoudis, V.; Vlastou, V.; Wallner, A.; Ware, T.; Weigand, M.; Weiß, C.; Wright, T.; Zǔgec
2013-12-01
Above 1 MeV of incident neutron energy the fission fragment angular distribution (FFAD) has generally a strong anisotropic behavior due to the combination of the incident orbital momentum and the intrinsic spin of the fissioning nucleus. This effect has to be taken into account for the efficiency estimation of devices used for fission cross section measurements. In addition it bears information on the spin deposition mechanism and on the structure of transitional states. We designed and constructed a detection device, based on Parallel Plate Avalanche Counters (PPAC), for measuring the fission fragment angular distributions of several isotopes, in particular 232Th. The measurement has been performed at n_TOF at CERN taking advantage of the very broad energy spectrum of the neutron beam. Fission events were recognized by back to back detection in coincidence in two position-sensitive detectors surrounding the targets. The detection efficiency, depending mostly on the stopping of fission fragments in backings and electrodes, has been computed with a Geant4 simulation and validated by the comparison to the measured case of 235U below 3 keV where the emission is isotropic. In the case of 232Th, the result is in good agreement with previous data below 10 MeV, with a good reproduction of the structures associated to vibrational states and the opening of second chance fission. In the 14 MeV region our data are much more accurate than previous ones which are broadly scattered.
Angular distribution in the neutron-induced fission of actinides
Directory of Open Access Journals (Sweden)
Leong L.S.
2013-12-01
Full Text Available Above 1 MeV of incident neutron energy the fission fragment angular distribution (FFAD has generally a strong anisotropic behavior due to the combination of the incident orbital momentum and the intrinsic spin of the fissioning nucleus. This effect has to be taken into account for the efficiency estimation of devices used for fission cross section measurements. In addition it bears information on the spin deposition mechanism and on the structure of transitional states. We designed and constructed a detection device, based on Parallel Plate Avalanche Counters (PPAC, for measuring the fission fragment angular distributions of several isotopes, in particular 232Th. The measurement has been performed at n_TOF at CERN taking advantage of the very broad energy spectrum of the neutron beam. Fission events were recognized by back to back detection in coincidence in two position-sensitive detectors surrounding the targets. The detection efficiency, depending mostly on the stopping of fission fragments in backings and electrodes, has been computed with a Geant4 simulation and validated by the comparison to the measured case of 235U below 3 keV where the emission is isotropic. In the case of 232Th, the result is in good agreement with previous data below 10 MeV, with a good reproduction of the structures associated to vibrational states and the opening of second chance fission. In the 14 MeV region our data are much more accurate than previous ones which are broadly scattered.
Horseshoe orbits in the restricted four-body problem
Burgos-Garcia, Jaime; Bengochea, Abimael
2017-11-01
The circular restricted four-body problem studies the dynamics of a massless particle under the gravitational force produced by three point masses that follow circular orbits with constant angular velocity, the configuration of these circular orbits forms an equilateral triangle for all time; this problem can be considered as an extension of the celebrated restricted three-body problem. In this work we investigate the orbits which emanate from some equilibrium points. In particular, we focus on the horseshoe shaped orbits (rotating frame), which are well known in the restricted three-body problem. We study some families of symmetric horseshoe orbits and show their relation with a family of the so called Lyapunov orbits.
A Geostationary Earth Orbit Satellite Model Using Easy Java Simulation
Wee, Loo Kang; Goh, Giam Hwee
2013-01-01
We develop an Easy Java Simulation (EJS) model for students to visualize geostationary orbits near Earth, modelled using a Java 3D implementation of the EJS 3D library. The simplified physics model is described and simulated using a simple constant angular velocity equation. We discuss four computer model design ideas: (1) a simple and realistic…
Bigger Stores, More Stores, or No Stores: Paths of Retail Restructuring in Rural America
Vias, Alexander C.
2004-01-01
Changes such as the development of large international retail chains, retail concentration, locational changes, technological innovation, new labor practices, and the increasing scale of individual stores, have revolutionized the retail sector. This broad restructuring will have profound impacts in rural America because employment in retail is a…
He, Li; Li, Huan; Li, Mo
2016-09-01
Photons carry linear momentum and spin angular momentum when circularly or elliptically polarized. During light-matter interaction, transfer of linear momentum leads to optical forces, whereas transfer of angular momentum induces optical torque. Optical forces including radiation pressure and gradient forces have long been used in optical tweezers and laser cooling. In nanophotonic devices, optical forces can be significantly enhanced, leading to unprecedented optomechanical effects in both classical and quantum regimes. In contrast, to date, the angular momentum of light and the optical torque effect have only been used in optical tweezers but remain unexplored in integrated photonics. We demonstrate the measurement of the spin angular momentum of photons propagating in a birefringent waveguide and the use of optical torque to actuate rotational motion of an optomechanical device. We show that the sign and magnitude of the optical torque are determined by the photon polarization states that are synthesized on the chip. Our study reveals the mechanical effect of photon's polarization degree of freedom and demonstrates its control in integrated photonic devices. Exploiting optical torque and optomechanical interaction with photon angular momentum can lead to torsional cavity optomechanics and optomechanical photon spin-orbit coupling, as well as applications such as optomechanical gyroscopes and torsional magnetometry.
Origin of molecular orbital splitting of C-60 on Al(110)
Schiessling, J; Stener, M; Balasubramanian, T; Kjeldgaard, L; Decleva, P; Nordgren, J; Bruhwiler, PA
2004-01-01
We have investigated the C-60 monolayer on Al(l 10) with angle-dependent photoelectron spectroscopy. We find that orbital components have different angular distributions. Calculations of cross sections of the highest occupied molecular orbital components for free, oriented C-60 are found to describe
A Detailed Derivation of Gaussian Orbital-Based Matrix Elements in Electron Structure Calculations
Petersson, T.; Hellsing, B.
2010-01-01
A detailed derivation of analytic solutions is presented for overlap, kinetic, nuclear attraction and electron repulsion integrals involving Cartesian Gaussian-type orbitals. It is demonstrated how s-type orbitals can be used to evaluate integrals with higher angular momentum via the properties of Hermite polynomials and differentiation with…
Interrogation of orbital structure by elliptically polarized intense femtosecond laser pulses
DEFF Research Database (Denmark)
Abu-Samha, Mahmoud; Madsen, Lars Bojer
2011-01-01
We solve the three-dimensional time-dependent Schrödinger equation and present investigations of the imprint of the orbital angular node in photoelectron momentum distributions of an aligned atomic p-type orbital following ionization by an intense elliptically polarized laser pulse of femtosecond...
How much mass and angular momentum can the progenitors of carbon-enriched stars accrete?
Matrozis, E.; Abate, C.; Stancliffe, R. J.
2017-10-01
The chemically peculiar barium stars, CH stars, and most carbon-enhanced metal-poor (CEMP) stars are all believed to be the products of mass transfer in binary systems from a now extinct asymptotic giant branch (AGB) primary star. The mass of the AGB star and the orbital parameters of the system are the key factors usually considered when determining how much mass is transferred onto the lower-mass main-sequence companion. What is usually neglected, however, is the angular momentum of the accreted material, which should spin up the accreting star. If the star reaches critical rotation, further accretion should cease until the excess angular momentum is somehow dealt with. If the star cannot redistribute or lose the angular momentum while the primary is on the AGB, the amount of mass accreted could be much lower than otherwise expected. Here we present calculations, based on detailed stellar evolution models, of the mass that can be accreted by putative progenitors of Ba and CEMP stars before they reach critical rotation under the assumption that no angular momentum loss occurs during the mass transfer. We consider different accretion rates and values of specific angular momentum. The most stringent limits on the accreted masses result from considering accretion from a Keplerian accretion disk, which is likely present during the formation of most extrinsically-polluted carbon-enriched stars. Our calculations indicate that in this scenario only about 0.05 M⊙ of material can be added to the accreting star before it reaches critical rotation, which is much too low to explain the chemical enrichment of many Ba and CEMP stars. Either the specific angular momentum of the accreted material has to effectively be lower by about a factor of ten than the Keplerian value, or significant angular momentum losses must occur for substantial accretion to take place.
Angular momentum conservation for dynamical black holes
Hayward, Sean A.
2006-11-01
Angular momentum can be defined by rearranging the Komar surface integral in terms of a twist form, encoding the twisting around of space-time due to a rotating mass, and an axial vector. If the axial vector is a coordinate vector and has vanishing transverse divergence, it can be uniquely specified under certain generic conditions. Along a trapping horizon, a conservation law expresses the rate of change of angular momentum of a general black hole in terms of angular momentum densities of matter and gravitational radiation. This identifies the transverse-normal block of an effective gravitational-radiation energy tensor, whose normal-normal block was recently identified in a corresponding energy conservation law. Angular momentum and energy are dual, respectively, to the axial vector and a previously identified vector, the conservation equations taking the same form. Including charge conservation, the three conserved quantities yield definitions of an effective energy, electric potential, angular velocity and surface gravity, satisfying a dynamical version of the so-called first law of black-hole mechanics. A corresponding zeroth law holds for null trapping horizons, resolving an ambiguity in taking the null limit.
Engorgement of the Angular and Temporal Veins Following Periorbital Hyaluronic Acid Gel Injection.
Pimentel de Miranda, Aline; Nassiri, Nariman; Goldberg, Robert A
2016-01-01
To study angular and temporal vein engorgement following periorbital hyaluronic acid gel (HAG) injection. In this retrospective study, the authors reviewed the photographs of 805 patients who had periorbital HAG injection at Jules Stein Eye Institute Oculoplastic Clinic between January 2004 and January 2014. HAG injections were used to fill the orbital hollow, zygomatic hollow, septal confluence hollow, and cheek. The inclusion criteria were patients who had at least 1 pre-, immediate post-, and late postinjection photographs. Immediate postinjection photographs were taken right after HAG injection, and late postinjection photographs were taken at the following visit before any injection. The exclusion criteria were patients with any previous ocular surgery 6 months before filler injection, patients with orbital diseases, and patients who had HAG injections for functional purposes. The photographs were evaluated for the presence of angular and temporal vein engorgement at any of the injections during the follow-up visits. The photographs of eyes with vein engorgement were graded on a scale of 0 (no engorgement), 1 (mild engorgement), 2 (moderate engorgement), and 3 (severe engorgement). There were 78 eligible patients (156 orbits; 68 females and 10 males) with average age of 59.4 ± 13.4 years. The authors found 18 orbits of 12 patients (15.4%; 6 unilateral and 6 bilateral) with angular vein engorgement at least 1 time after HAG injection during the follow-up visits. The frequency of temporal vein engorgement was 9.1%. The mean ± SD of angular vein grading for engorgement increased from 0.72 ± 0.51 on preinjection photographs to 1.45 ± 0.88 on immediate postinjection photographs (p = 0.0001) and 0.89 ± 0.50 on late postinjection photographs (p = 0.04). The mean ± SD of angular vein grading for engorgement was 0.67 ± 0.55 on the first preinjection photographs, which increased to 1.10 ± 0.50 on the last late postinjection photographs
Variation in Angular Velocity and Angular Acceleration of a Particle in Rectilinear Motion
Mashood, K. K.; Singh, V. A.
2012-01-01
We discuss the angular velocity ([image omitted]) and angular acceleration ([image omitted]) associated with a particle in rectilinear motion with constant acceleration. The discussion was motivated by an observation that students and even teachers have difficulty in ascribing rotational motion concepts to a particle when the trajectory is a…
Angular Spectral Analysis and Lowpass Filtering of Aeromagnetic ...
African Journals Online (AJOL)
Total-field aeromagnetic data over the western half of the Bornu basin and its surrounding areas were analyzed using angular spectral analysis, upward continuation and lowpass filtering techniques. Results revealed several angular spectral peaks at various angular orientations. The angular orientations correlated with the ...
Data-oriented development with AngularJS
Waikar, Manoj
2015-01-01
This book helps beginner-level AngularJS developers organize AngularJS applications by discussing important AngularJS concepts and best practices. If you are an experienced AngularJS developer but haven't written directives or haven't created custom HTML controls before, then this book is ideal for you.
Chirality and angular momentum in optical radiation
Coles, Matt M
2012-01-01
This paper develops, in precise quantum electrodynamic terms, photonic attributes of the "optical chirality density", one of several measures long known to be conserved quantities for a vacuum electromagnetic field. The analysis lends insights into some recent interpretations of chiroptical experiments, in which this measure, and an associated chirality flux, have been treated as representing physically distinctive "superchiral" phenomena. In the fully quantized formalism the chirality density is promoted to operator status, whose exploration with reference to an arbitrary polarization basis reveals relationships to optical angular momentum and helicity operators. Analyzing multi-mode beams with complex wave-front structures, notably Laguerre-Gaussian modes, affords a deeper understanding of the interplay between optical chirality and optical angular momentum. By developing theory with due cognizance of the photonic character of light, it emerges that only the spin angular momentum of light is engaged in such...
Modelling flow phenomena in time dependent store release from transonic aircraft
CSIR Research Space (South Africa)
MacLucas, David A
2014-07-01
Full Text Available solver was initialised using the linear and angular velocities measured by the CTS at the end of the ejector stroke. Since the store has been constrained until the end of the carriage time, the aerodynamic forces on the store were introduced linearly... quad-core machines (i.e. 48 cores). This resulted in 0.19 s of full- scale release time after the end of the nominal ejector stroke. This represents about a third of the remaining release time available from the experimental data. Further work...
Song, H. F.; Meynet, G.; Maeder, A.; Ekström, S.; Eggenberger, P.; Georgy, C.; Qin, Y.; Fragos, T.; Soerensen, M.; Barblan, F.; Wade, G. A.
2018-01-01
Context. Massive stars with solar metallicity lose important amounts of rotational angular momentum through their winds. When a magnetic field is present at the surface of a star, efficient angular momentum losses can still be achieved even when the mass-loss rate is very modest, at lower metallicities, or for lower-initial-mass stars. In a close binary system, the effect of wind magnetic braking also interacts with the influence of tides, resulting in a complex evolution of rotation. Aims: We study the interactions between the process of wind magnetic braking and tides in close binary systems. Methods: We discuss the evolution of a 10 M⊙ star in a close binary system with a 7 M⊙ companion using the Geneva stellar evolution code. The initial orbital period is 1.2 days. The 10 M⊙ star has a surface magnetic field of 1 kG. Various initial rotations are considered. We use two different approaches for the internal angular momentum transport. In one of them, angular momentum is transported by shear and meridional currents. In the other, a strong internal magnetic field imposes nearly perfect solid-body rotation. The evolution of the primary is computed until the first mass-transfer episode occurs. The cases of different values for the magnetic fields and for various orbital periods and mass ratios are briefly discussed. Results: We show that, independently of the initial rotation rate of the primary and the efficiency of the internal angular momentum transport, the surface rotation of the primary will converge, in a time that is short with respect to the main-sequence lifetime, towards a slowly evolving velocity that is different from the synchronization velocity. This "equilibrium angular velocity" is always inferior to the angular orbital velocity. In a given close binary system at this equilibrium stage, the difference between the spin and the orbital angular velocities becomes larger when the mass losses and/or the surface magnetic field increase. The
The equations of relative motion in the orbital reference frame
Casotto, Stefano
2016-03-01
The analysis of relative motion of two spacecraft in Earth-bound orbits is usually carried out on the basis of simplifying assumptions. In particular, the reference spacecraft is assumed to follow a circular orbit, in which case the equations of relative motion are governed by the well-known Hill-Clohessy-Wiltshire equations. Circular motion is not, however, a solution when the Earth's flattening is accounted for, except for equatorial orbits, where in any case the acceleration term is not Newtonian. Several attempts have been made to account for the J_2 effects, either by ingeniously taking advantage of their differential effects, or by cleverly introducing ad-hoc terms in the equations of motion on the basis of geometrical analysis of the J_2 perturbing effects. Analysis of relative motion about an unperturbed elliptical orbit is the next step in complexity. Relative motion about a J_2-perturbed elliptic reference trajectory is clearly a challenging problem, which has received little attention. All these problems are based on either the Hill-Clohessy-Wiltshire equations for circular reference motion, or the de Vries/Tschauner-Hempel equations for elliptical reference motion, which are both approximate versions of the exact equations of relative motion. The main difference between the exact and approximate forms of these equations consists in the expression for the angular velocity and the angular acceleration of the rotating reference frame with respect to an inertial reference frame. The rotating reference frame is invariably taken as the local orbital frame, i.e., the RTN frame generated by the radial, the transverse, and the normal directions along the primary spacecraft orbit. Some authors have tried to account for the non-constant nature of the angular velocity vector, but have limited their correction to a mean motion value consistent with the J_2 perturbation terms. However, the angular velocity vector is also affected in direction, which causes precession
Directory of Open Access Journals (Sweden)
Potter F.
2016-01-01
Full Text Available In July, 2015, the New Horizons spacecraft passing by Pluto did not discover any more moons. Therefore, we know the Pluto system total angular momentum to within 2.4%, more accurately than any other system with more than two orbiting bodies. We there- fore update our previous analysis to determine whether a definitive test of the quantum celestial mechanics (QCM angular momentum constraint can now be achieved.
Directory of Open Access Journals (Sweden)
Ron Tolmie
2014-11-01
Full Text Available Heat can be collected from local energy sources and concentrated into a relatively small volume, and at a useful working temperature, by using a heat pump as the concentrator. That heat can be stored and utilized at a later date for applications like space heating. The process is doing two things at the same time: storing heat and shifting the power demand. The concentration step can be done at night when there is normally a surplus of power and its timing can be directly controlled by the power grid operator to ensure that the power consumption occurs only when adequate power is available. The sources of heat can be the summer air, the heat extracted from buildings by their cooling systems, natural heat from the ground or solar heat, all of which are free, abundant and readily accessible. Such systems can meet the thermal needs of buildings while at the same time stabilizing the grid power demand, thus reducing the need for using fossil-fuelled peaking power generators. The heat pump maintains the temperature of the periphery at the ambient ground temperature so very little energy is lost during storage.
A Novel Permanent Magnetic Angular Acceleration Sensor
Directory of Open Access Journals (Sweden)
Hao Zhao
2015-07-01
Full Text Available Angular acceleration is an important parameter for status monitoring and fault diagnosis of rotary machinery. Therefore, we developed a novel permanent magnetic angular acceleration sensor, which is without rotation angle limitations and could directly measure the instantaneous angular acceleration of the rotating system. The sensor rotor only needs to be coaxially connected with the rotating system, which enables convenient sensor installation. For the cup structure of the sensor rotor, it has a relatively small rotational inertia. Due to the unique mechanical structure of the sensor, the output signal of the sensor can be directed without a slip ring, which avoids signal weakening effect. In this paper, the operating principle of the sensor is described, and simulated using finite element method. The sensitivity of the sensor is calibrated by torsional pendulum and angle sensor, yielding an experimental result of about 0.88 mV/(rad·s−2. Finally, the angular acceleration of the actual rotating system has been tested, using both a single-phase asynchronous motor and a step motor. Experimental result confirms the operating principle of the sensor and indicates that the sensor has good practicability.
Temperature and angular momentum dependence of the ...
Indian Academy of Sciences (India)
Temperature and angular momentum dependence of the quadrupole deformation is studied in the middle of the sd-shell for 28Si and 27Si isotopes using the spherical shell model approach. The shell model calculations have been performed using the standard universal sd-shell (USD) interaction and the canonical ...
Angular Momentum Transport in Accretion Disks
DEFF Research Database (Denmark)
E. Pessah, Martin; Chan, Chi-kwan; Psaltis, Dimitrios
2007-01-01
if the resolution were set equal to the natural dissipation scale in astrophysical disks. We conclude that, in order for MRI-driven turbulent angular momentum transport to be able to account for the large value of the effective alpha viscosity inferred observationally, the disk must be threaded by a significant...
Angular and linear momentum of excited ferromagnets
Yan, P.; Kamra, A.; Cao, Y.; Bauer, G.E.W.
2013-01-01
The angular momentum vector of a Heisenberg ferromagnet with isotropic exchange interaction is conserved, while under uniaxial crystalline anisotropy the projection of the total spin along the easy axis is a constant of motion. Using Noether's theorem, we prove that these conservation laws persist
Angular correlations near the Fermi energy
Fox, D.; Cebra, D.A.; Karn, J.; Parks, C.; Pradhan, A.; Plicht, J. van der; Westfall, G.D.; Wilson, W.K.; Tickle, R.S.
1988-01-01
Angular correlations between light particles have been studied to probe the extent to which a thermally equilibrated system is formed in heavy ion collisions near the Fermi energy. Single-light-particle inclusive energy spectra and two-particle large-angle correlations were measured for 40 and 50
Angular Spectrum Simulation of Pulsed Ultrasound Fields
DEFF Research Database (Denmark)
Du, Yigang; Jensen, Henrik; Jensen, Jørgen Arendt
2009-01-01
geometries for any kind of focusing and apodization. The Angular Spectrum Approach (ASA) is capable of simulating monochromatic non-linear acoustic wave propagation. However, for ultrasound imaging the time response of each specific point in space is required, and a pulsed ASA simulation with multi temporal...
Enhanced spin-orbit interaction during ultrafast demagnetization of nickel
Energy Technology Data Exchange (ETDEWEB)
Stamm, Christian; Pontius, Niko; Kachel, Torsten; Wietstruk, Marko; Duerr, Hermann A. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Elektronenspeicherring BESSY II, Berlin (Germany)
2010-07-01
Time-resolved X-ray absorption spectroscopy (XAS) allows for a detailed view of microscopic processes during ultrafast demagnetization following a laser pump pulse. Previously we have shown that both spin and orbital angular momentum are quenched within a few 100 fs, utilizing the X-ray magnetic circular dichroism (XMCD) sum rules. In addition, XAS is able to measure the spin-orbit interaction by quantifying the absorption ratio between the spin-orbit split L3, L2 absorption edges, the so-called branching ratio. We find an increase of the spin-orbit coupling just after laser excitation, which persists during the demagnetization process. This is the first experimental demonstration of laser-enhanced spin-orbit interaction.
Gauge Freedom in Orbital Mechanics
Efroimsky, Michael
2005-12-01
In orbital and attitude dynamics the coordinates and the Euler angles are expressed as functions of the time and six constants called elements. Under disturbance, the constants are endowed with time dependence. The Lagrange constraint is then imposed to guarantee that the functional dependence of the perturbed velocity on the time and constants stays the same as in the undisturbed case. Constants obeying this condition are called osculating elements. The constants chosen to be canonical are called Delaunay elements, in the orbital case, or Andoyer elements, in the spin case. (As some Andoyer elements are time dependent even in the free-spin case, the role of constants is played by their initial values.) The Andoyer and Delaunay sets of elements share a feature not readily apparent: in certain cases the standard equations render them non-osculating. In orbital mechanics, elements furnished by the standard planetary equations are non-osculating when perturbations depend on velocities. To preserve osculation, the equations must be amended with extra terms that are not parts of the disturbing function. In the case of Delaunay parameterisation, these terms destroy canonicity. So under velocity-dependent disturbances, osculation and canonicity are incompatible. (Efroimsky and Goldreich 2003, 2004) Similarly, the Andoyer elements turn out to be non-osculating under angular-velocity-dependent perturbation. Amendment of only the Hamiltonian makes the equations render nonosculating elements. To make them osculating, more terms must enter the equations (and the equations will no longer be canonical). In practical calculations, is often convenient to deliberately deviate from osculation by substituting the Lagrange constraint with a condition that gives birth to a family of nonosculating elements.
In-Store Media and Channel Management
Anthony Dukes; Yunchuan Liu
2007-01-01
In this paper, we study the interesting and complicated effects of retailer in-store media on distribution channel relationships. With the help of advanced technology, retailers can open in-store media in their stores and allow manufacturers to advertise through the instore media. We show that opening in-store media is a strategic decision for a retailer, and a retailer may strategically subsidize manufacturers on their advertising through instore media to better coordinate the channel. Even ...
2010-04-01
... 19 Customs Duties 1 2010-04-01 2010-04-01 false Stores list. 122.47 Section 122.47 Customs Duties... Overflying the United States § 122.47 Stores list. (a) When required. A stores list shall be filed for all aircraft required to enter under § 122.41. (b) Form. The aircraft stores shall be listed on the cargo...
Spin–orbit coupling in actinide cations
DEFF Research Database (Denmark)
Bagus, Paul S.; Ilton, Eugene S.; Martin, Richard L.
2012-01-01
The limiting case of Russell–Saunders coupling, which leads to a maximum spin alignment for the open shell electrons, usually explains the properties of high spin ionic crystals with transition metals. For actinide compounds, the spin–orbit splitting is large enough to cause a significantly reduc...... spin alignment. Novel concepts are used to explain the dependence of the spin alignment on the 5f shell occupation. We present evidence that the XPS of ionic actinide materials may provide direct information about the angular momentum coupling within the 5f shell....
Mechanism of store-operated calcium entry
Indian Academy of Sciences (India)
Activation of receptors coupled to the phospholipase C/IP3 signalling pathway results in a rapid release of calcium from its intracellular stores, eventually leading to depletion of these stores. Calcium store depletion triggers an influx of extracellular calcium across the plasma membrane, a mechanism known as the ...
Preseptal Cellulitis, Orbital Cellulitis, Orbital Abscess
Directory of Open Access Journals (Sweden)
Rana Altan Yaycıoğlu
2012-12-01
Full Text Available Patients with orbital infections present to our clinic usually with unilateral pain, hyperemia, and edema of the eyelids. The differentiation between preseptal and orbital cellulitis is utmost important in that the second requires hospitalization. Since in orbital cellulitis, the tissues posterior to the orbital septum are involved, signs such as conjunctival chemosis, limited eye movement, decreased vision, as well as afferent pupil defect secondary to optic nerve involvement may also be observed. Prompt intravenous antibiotic treatment should be started, and surgical drainage may be performed if patient shows failure to improve in 48 hours despite optimal management. Without treatment, the clinical course may progress to subperiosteal or orbital abscess, and even to cavernous sinus thrombosis. (Turk J Ophthalmol 2012; 42: Supplement 52-6
Devries, P. L.; George, T. F.
1978-01-01
The problem of two atoms colliding in the presence of an intense radiation field, such as that of a laser, is investigated. The radiation field, which couples states of different electronic symmetry, is described by the number state representation while the electronic degrees of freedom (plus spin-orbit interaction) are discussed in terms of a diabatic representation. The total angular momentum of the field-free system and the angular momentum transferred by absorption (or emission) of a photon are explicitly considered in the derivation of the coupled scattering equations. A model calculation is discussed for the Xe + F collision system.
Ion and electron angular distributions in the Io torus region of the Jovian magnetosphere
Lanzerotti, L. J.; Maclennan, C. G.; Armstrong, T. P.; Krimigis, S. M.; Lepping, R. P.; Ness, N. F.
1981-01-01
Angular distributions are presented of ion (about 0.5-2 MeV) and electron (greater than 10 MeV) fluxes measured during the Voyager 1 spacecraft passage through the inner regions of the Jovian magnetosphere. In the regions of peak flux intensities, just outside the orbit of Io, the ion angular distributions are most sharply peaked at 90 deg local pitch angle, a configuration consistent with diffusion of the particles inward from large radial distances. Inside the orbit of Io the lower-energy ions exhibit angular distributions depleted at 90 deg local pitch angles, suggesting the possibility of charge-exchange scattering loss of these particles. In the vicinity of the Io flux tube, no significant effect is observed in the flux or pitch angle distributions of the ions. The relativistic electrons are depleted in the flux tube region and exhibit an asymmetrical pitch angle distribution, with more electrons appearing to arrive from the equatorial region (the direction of Io) than from the low-altitude mirror point.
Transneptunian Orbit Computation
Virtanen, J.; Tancredi, G.; Bernstein, G. M.; Spahr, T.; Muinonen, K.
We review the orbit computation problem for the transneptunian population. For these distant objects, the problem is characterized by their short observed orbital arcs, which are known to be coupled with large uncertainties in orbital elements. Currently, the observations of even the best observed objects, such as the first-ever transneptunian object (TNO), Pluto, cover only a fraction of their revolution. Furthermore, of the some 1200 objects discovered since 1992, roughly half have observations from only one opposition. To ensure realistic analyses of the population, e.g., in the derivation of unbiased orbital distributions or correlations between orbital and physical properties, realistic estimation of orbital uncertainties is important. We describe the inverse problem of orbit computation, emphasizing the short-arc problem and its statistical treatment. The complete solution to the problem can be given in terms of the orbital-element probability density function (p.d.f.), which then serves as a starting point for any further analysis, where knowledge of orbital uncertainties is required. We give an overview of the variety of computational techniques developed for TNO orbital uncertainty estimation in the recent years. After presenting the current orbital distribution, we demonstrate their application to several prediction problems, such as classification, ephemeris prediction, and dynamical analysis of objects. We conclude with some future prospects for TNO orbit computation concerning the forthcoming next-generation surveys, including the anticipated evolution of TNO orbital uncertainties over the coming decades.
Integrated accretion disk angular momentum removal and astrophysical jet acceleration mechanism
Bellan, Paul
2015-11-01
A model has been developed for how accretion disks discard angular momentum while powering astrophysical jets. The model depends on the extremely weak ionization of disks. This causes disk ions to be collisionally locked to adjacent disk neutrals so a clump of disk ions and neutrals has an effective cyclotron frequency αωci where α is the fractional ionization. When αωci is approximately twice the Kepler orbital frequency, conservation of canonical momentum shows that the clump spirals radially inwards producing a radially inward disk electric current as electrons cannot move radially in the disk. Upon reaching the jet radius, this current then flows axially away from the disk plane along the jet, producing a toroidal magnetic field that drives the jet. Electrons remain frozen to poloidal flux surfaces everywhere and electron motion on flux surfaces in the ideal MHD region outside the disk completes the current path. Angular momentum absorbed from accreting material in the disk by magnetic counter-torque -JrBz is transported by the electric circuit and ejected at near infinite radius in the disk plane. This is like an electric generator absorbing angular momentum and wired to a distant electric motor that emits angular momentum. Supported by USDOE/NSF Partnership in Plasma Science.
DEFF Research Database (Denmark)
Riis, Troels; Jørgensen, John Leif
1999-01-01
This documents describes a test of the implementation of the ASC orbit model for the Champ satellite.......This documents describes a test of the implementation of the ASC orbit model for the Champ satellite....
National Aeronautics and Space Administration — The Lunar Orbiter Photo Gallery is an extensive collection of over 2,600 high- and moderate-resolution photographs produced by all five of the Lunar Orbiter...
Mars Molniya Orbit Atmospheric Resource Mining
Mueller, Robert P.; Braun, Robert D.; Sibille, Laurent; Sforzo, Brandon; Gonyea, Keir; Ali, Hisham
2016-01-01
This NIAC (NASA Advanced Innovative Concepts) work will focus on Mars and will build on previous efforts at analyzing atmospheric mining at Earth and the outer solar system. Spacecraft systems concepts will be evaluated and traded, to assess feasibility. However the study will primarily examine the architecture and associated missions to explore the closure, constraints and critical parameters through sensitivity studies. The Mars atmosphere consists of 95.5 percent CO2 gas which can be converted to methane fuel (CH4) and Oxidizer (O2) for chemical rocket propulsion, if hydrogen is transported from electrolyzed water on the Mars surface or from Earth. By using a highly elliptical Mars Molniya style orbit, the CO2 atmosphere can be scooped, ram-compressed and stored while the spacecraft dips into the Mars atmosphere at periapsis. Successive orbits result in additional scooping of CO2 gas, which also serves to aerobrake the spacecraft, resulting in a decaying Molniya orbit.
Power spectra of the angular fractals
Zhong, Xihua; Zhu, Yafen; Zhou, Yueming
1993-09-01
Based on the angular backbone taken from the triangular Sierpinski gasket, several seLf-similar structures are disigned, corresponding diffraction screens are made, and the Fraunhofer patterns as power spectra of them are given. Based upon a viewpoint of generative production and by means of the ui-branched displacement operation, we have found the recurrence formulae of spectral structure factor for these angular fractals. As a example, the recurrence formulae of power spectra for a coherent point group is given, corresponding a series of curves as well as an isogram are plotted. The analysis of result shows that the power spectra of this fractal point group has a rotation symmetry and a mirror symmetry, and appears a period doubling phenomenon which follows the process of generative production.
Introducing Earth's Orbital Eccentricity
Oostra, Benjamin
2015-01-01
Most students know that planetary orbits, including Earth's, are elliptical; that is Kepler's first law, and it is found in many science textbooks. But quite a few are mistaken about the details, thinking that the orbit is very eccentric, or that this effect is somehow responsible for the seasons. In fact, the Earth's orbital eccentricity is…
Idiopathic granulomatous orbital inflammation
Mombaerts, I.; Schlingemann, R. O.; Goldschmeding, R.; Koornneef, L.
1996-01-01
PURPOSE: Granulomatous orbital inflammation may occur as an isolated condition of unknown origin. These idiopathic granulomatous lesions are believed to belong to the orbital pseudotumor group by some authors, whereas others consider them sarcoidosis limited to the orbit. The aim of this study is to
The Angular Trispectrum of the CMB
Hu, Wayne
2001-01-01
We study the general properties of the CMB temperature four-point function, specifically its harmonic analogue the angular trispectrum, and illustrate its utility in finding optimal quadratic statistics through the weak gravitational lensing effect. We determine the general form of the trispectrum, under the assumptions of rotational, permutation, and parity invariance, its estimators on the sky, and their Gaussian noise properties. The signal-to-noise in the trispectrum can be highly configu...
Coherent Control of Photoelectron Wavepacket Angular Interferograms
Hockett, Paul; Wollenhaupt, Matthias; Baumert, Thomas
2015-01-01
Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the cohere...
A UNIFIED FRAMEWORK FOR THE ORBITAL STRUCTURE OF BARS AND TRIAXIAL ELLIPSOIDS
Energy Technology Data Exchange (ETDEWEB)
Valluri, Monica; Abbott, Caleb [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Shen, Juntai [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Debattista, Victor P., E-mail: mvalluri@umich.edu, E-mail: calebga@umich.edu, E-mail: jshen@shao.ac.cn, E-mail: vpdebattista@uclan.ac.uk [Jeremiah Horrocks Institute, University of Central Lancashire, Preston, PR1 2HE (United Kingdom)
2016-02-20
We examine a large random sample of orbits in two self-consistent simulations of N-body bars. Orbits in these bars are classified both visually and with a new automated orbit classification method based on frequency analysis. The well-known prograde x1 orbit family originates from the same parent orbit as the box orbits in stationary and rotating triaxial ellipsoids. However, only a small fraction of bar orbits (∼4%) have predominately prograde motion like their periodic parent orbit. Most bar orbits arising from the x1 orbit have little net angular momentum in the bar frame, making them equivalent to box orbits in rotating triaxial potentials. In these simulations a small fraction of bar orbits (∼7%) are long-axis tubes that behave exactly like those in triaxial ellipsoids: they are tipped about the intermediate axis owing to the Coriolis force, with the sense of tipping determined by the sign of their angular momentum about the long axis. No orbits parented by prograde periodic x2 orbits are found in the pure bar model, but a tiny population (∼2%) of short-axis tube orbits parented by retrograde x4 orbits are found. When a central point mass representing a supermassive black hole (SMBH) is grown adiabatically at the center of the bar, those orbits that lie in the immediate vicinity of the SMBH are transformed into precessing Keplerian orbits that belong to the same major families (short-axis tubes, long-axis tubes and boxes) occupying the bar at larger radii. During the growth of an SMBH, the inflow of mass and outward transport of angular momentum transform some x1 and long-axis tube orbits into prograde short-axis tubes. This study has important implications for future attempts to constrain the masses of SMBHs in barred galaxies using orbit-based methods like the Schwarzschild orbit superposition scheme and for understanding the observed features in barred galaxies.
The Cosmology Large Angular Scale Surveyor
Harrington, Kathleen; Marriage, Tobias; Ali, Aamir; Appel, John; Bennett, Charles; Boone, Fletcher; Brewer, Michael; Chan, Manwei; Chuss, David T.; Colazo, Felipe;
2016-01-01
The Cosmology Large Angular Scale Surveyor (CLASS) is a four telescope array designed to characterize relic primordial gravitational waves from inflation and the optical depth to reionization through a measurement of the polarized cosmic microwave background (CMB) on the largest angular scales. The frequencies of the four CLASS telescopes, one at 38 GHz, two at 93 GHz, and one dichroic system at 145217 GHz, are chosen to avoid spectral regions of high atmospheric emission and span the minimum of the polarized Galactic foregrounds: synchrotron emission at lower frequencies and dust emission at higher frequencies. Low-noise transition edge sensor detectors and a rapid front-end polarization modulator provide a unique combination of high sensitivity, stability, and control of systematics. The CLASS site, at 5200 m in the Chilean Atacama desert, allows for daily mapping of up to 70% of the sky and enables the characterization of CMB polarization at the largest angular scales. Using this combination of a broad frequency range, large sky coverage, control over systematics, and high sensitivity, CLASS will observe the reionization and recombination peaks of the CMB E- and B-mode power spectra. CLASS will make a cosmic variance limited measurement of the optical depth to reionization and will measure or place upper limits on the tensor-to-scalar ratio, r, down to a level of 0.01 (95% C.L.).
The Cosmology Large Angular Scale Surveyor (CLASS)
Harrington, Kathleen; Marriange, Tobias; Aamir, Ali; Appel, John W.; Bennett, Charles L.; Boone, Fletcher; Brewer, Michael; Chan, Manwei; Chuss, David T.; Colazo, Felipe;
2016-01-01
The Cosmology Large Angular Scale Surveyor (CLASS) is a four telescope array designed to characterize relic primordial gravitational waves from in ation and the optical depth to reionization through a measurement of the polarized cosmic microwave background (CMB) on the largest angular scales. The frequencies of the four CLASS telescopes, one at 38 GHz, two at 93 GHz, and one dichroic system at 145/217 GHz, are chosen to avoid spectral regions of high atmospheric emission and span the minimum of the polarized Galactic foregrounds: synchrotron emission at lower frequencies and dust emission at higher frequencies. Low-noise transition edge sensor detectors and a rapid front-end polarization modulator provide a unique combination of high sensitivity, stability, and control of systematics. The CLASS site, at 5200 m in the Chilean Atacama desert, allows for daily mapping of up to 70% of the sky and enables the characterization of CMB polarization at the largest angular scales. Using this combination of a broad frequency range, large sky coverage, control over systematics, and high sensitivity, CLASS will observe the reionization and recombination peaks of the CMB E- and B-mode power spectra. CLASS will make a cosmic variance limited measurement of the optical depth to reionization and will measure or place upper limits on the tensor-to-scalar ratio, r, down to a level of 0.01 (95% C.L.).
Verification of angular dependence in MOSFET detector
Energy Technology Data Exchange (ETDEWEB)
Souza, Clayton H.; Shorto, Julian M.B.; Siqueira, Paulo T.D.; Nunes, Maíra G.; Silva Junior, Iremar A.; Yoriyaz, Hélio, E-mail: chsouza@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)
2017-07-01
In vivo dosimetry is an essential tool for quality assurance programs, being a procedure commonly performed with thermoluminescent dosimeters (TLDs) or diodes. However, a type of dosimeter that has increasing popularity in recent years is the metal-oxide-semiconductor field effect transistor (MOSFET) detector. MOSFET dosimeters fulfill all the necessary characteristics to realize in vivo dosimetry since it has a small size, good precision and feasibility of measurement, as well as easy handling. Nevertheless, its true differential is to allow reading of the dose in real time, enabling immediate intervention in the correction of physical parameters deviations and anticipation of small anatomical changes in a patient during treatment. In order for MOSFET dosimeter to be better accepted in clinical routine, information reporting performance should be available frequently. For this reason, this work proposes to verify reproducibility and angular dependence of a standard sensitivity MOSFET dosimeter (TN-502RD-H) for Cs-137 and Co-60 sources. Experimental data were satisfactory and MOSFET dosimeter presented a reproducibility of 3.3% and 2.7% (1 SD) for Cs-137 and Co-60 sources, respectively. In addition, an angular dependence of up to 6.1% and 16.3% for both radioactive sources, respectively. It is conclusive that MOSFET dosimeter TN-502RD-H has satisfactory reproducibility and a considerable angular dependence, mainly for the Co-60 source. This means that although precise measurements, special attention must be taken for applications in certain anatomical regions in a patient. (author)
Angular momentum evolution of galaxies in EAGLE
Lagos, Claudia del P.; Theuns, Tom; Stevens, Adam R. H.; Cortese, Luca; Padilla, Nelson D.; Davis, Timothy A.; Contreras, Sergio; Croton, Darren
2017-02-01
We use the EAGLE cosmological hydrodynamic simulation suite to study the specific angular momentum of galaxies, j, with the aims of (i) investigating the physical causes behind the wide range of j at fixed mass and (ii) examining whether simple, theoretical models can explain the seemingly complex and non-linear nature of the evolution of j. We find that j of the stars, jstars, and baryons, jbar, are strongly correlated with stellar and baryon mass, respectively, with the scatter being highly correlated with morphological proxies such as gas fraction, stellar concentration, (u-r) intrinsic colour, stellar age and the ratio of circular velocity to velocity dispersion. We compare with available observations at z = 0 and find excellent agreement. We find that jbar follows the theoretical expectation of an isothermal collapsing halo under conservation of specific angular momentum to within ≈50 per cent, while the subsample of rotation-supported galaxies are equally well described by a simple model in which the disc angular momentum is just enough to maintain marginally stable discs. We extracted evolutionary tracks of the stellar spin parameter of EAGLE galaxies and found that the fate of their jstars at z = 0 depends sensitively on their star formation and merger histories. From these tracks, we identified two distinct physical channels behind low jstars galaxies at z = 0: (i) galaxy mergers, and (ii) early star formation quenching. The latter can produce galaxies with low jstars and early-type morphologies even in the absence of mergers.
Angular light modulator using optical blinds.
Bian, Zichao; Alhudaithy, Soliman; Wang, Zhe; Zhang, Zibang; Guo, Kaikai; Bian, Liheng; Tomizawa, Yuji; Satonick, Peter; Hoshino, Kazunori; Zheng, Guoan
2016-12-12
Spatial light modulator (SLM) is widely used in imaging applications for modulating light intensity and phase delay. In this paper, we report a novel device concept termed angular light modulator (ALM). Different from the SLM, the reported ALM employs a tunable blind structure to modulate the angular components of the incoming light waves. For spatial-domain light modulation, the ALM can be directly placed in front of an image sensor for selecting different angular light components. In this case, we can sweep the slat angle of the blind structure and capture multiple images corresponding to different perspectives. These images can then be back-projected for 3D tomographic refocusing. By using a fixed slat angle, we can also convert the incident-angle information into intensity variations for wavefront sensing or introduce a translational shift to the defocused object for high-speed autofocusing. For Fourier-domain light modulation, the ALM can be placed at the pupil plane of an optical system for reinforcing the light propagating trajectories. We show that a pupil-plane-modulated system is able to achieve a better resolution for out-of-focus objects while maintaining the same resolution for in-focus objects. The reported ALM can be fabricated on the chip level and controlled by an external magnetic field. It may provide new insights for developing novel imaging and vision devices.
A neural circuit for angular velocity computation
Directory of Open Access Journals (Sweden)
Samuel B Snider
2010-12-01
Full Text Available In one of the most remarkable feats of motor control in the animal world, some Diptera, such as the housefly, can accurately execute corrective flight maneuvers in tens of milliseconds. These reflexive movements are achieved by the halteres, gyroscopic force sensors, in conjunction with rapidly-tunable wing-steering muscles. Specifically, the mechanosensory campaniform sensilla located at the base of the halteres transduce and transform rotation-induced gyroscopic forces into information about the angular velocity of the fly's body. But how exactly does the fly's neural architecture generate the angular velocity from the lateral strain forces on the left and right halteres? To explore potential algorithms, we built a neuro-mechanical model of the rotation detection circuit. We propose a neurobiologically plausible method by which the fly could accurately separate and measure the three-dimensional components of an imposed angular velocity. Our model assumes a single sign-inverting synapse and formally resembles some models of directional selectivity by the retina. Using multidimensional error analysis, we demonstrate the robustness of our model under a variety of input conditions. Our analysis reveals the maximum information available to the fly given its physical architecture and the mathematics governing the rotation-induced forces at the haltere's end knob.
A neural circuit for angular velocity computation.
Snider, Samuel B; Yuste, Rafael; Packer, Adam M
2010-01-01
In one of the most remarkable feats of motor control in the animal world, some Diptera, such as the housefly, can accurately execute corrective flight maneuvers in tens of milliseconds. These reflexive movements are achieved by the halteres, gyroscopic force sensors, in conjunction with rapidly tunable wing steering muscles. Specifically, the mechanosensory campaniform sensilla located at the base of the halteres transduce and transform rotation-induced gyroscopic forces into information about the angular velocity of the fly's body. But how exactly does the fly's neural architecture generate the angular velocity from the lateral strain forces on the left and right halteres? To explore potential algorithms, we built a neuromechanical model of the rotation detection circuit. We propose a neurobiologically plausible method by which the fly could accurately separate and measure the three-dimensional components of an imposed angular velocity. Our model assumes a single sign-inverting synapse and formally resembles some models of directional selectivity by the retina. Using multidimensional error analysis, we demonstrate the robustness of our model under a variety of input conditions. Our analysis reveals the maximum information available to the fly given its physical architecture and the mathematics governing the rotation-induced forces at the haltere's end knob.
The Gauge-Invariant Angular Momentum Sum-Rule for the Proton
Shore, G.M.
2000-01-01
We give a gauge-invariant treatment of the angular momentum sum-rule for the proton in terms of matrix elements of three gauge-invariant, local composite operators. These matrix elements are decomposed into three independent form factors, one of which is the flavour singlet axial charge. We further show that the axial charge cancels out of the sum-rule, so that it is unaffacted by the axial anomaly. The three form factors are then related to the four proton spin components in the parton model, namely quark and gluon intrinsic spin and orbital angular momentum. The renormalisation of the three operators is determined to one loop from which the scale dependence and mixing of the spin components is derived under the constraint that the quark spin be scale-independent. We also show how the three form factors can be measured in experiments.
Optical Studies of Orbital Debris at GEO Using Two Telescopes
Seitzer, P.; Abercromby, K. J.; Rodriquez,H. M.; Barker, E.
2008-01-01
Beginning in March, 2007, optical observations of debris at geosynchronous orbit (GEO) were commenced using two telescopes simultaneously at the Cerro Tololo Inter-American Observatory (CTIO) in Chile. The University of Michigan's 0.6/0.9-m Schmidt telescope MODEST (for Michigan Orbital DEbris Survey Telescope) was used in survey mode to find objects that potentially could be at GEO. Because GEO objects only appear in this telescope's field of view for an average of 5 minutes, a full six-parameter orbit can not be determined. Interrupting the survey for follow-up observations leads to incompleteness in the survey results. Instead, as objects are detected on MODEST, initial predictions assuming a circular orbit are done for where the object will be for the next hour, and the objects are reacquired as quickly as possible on the CTIO 0.9-m telescope. This second telescope then follows-up during the first night and, if possible, over several more nights to obtain the maximum time arc possible, and the best six parameter orbit. Our goal is to obtain an initial orbit for all detected objects fainter than R = 15th in order to estimate the orbital distribution of objects selected on the basis of two observational criteria: magnitude and angular rate. Objects fainter than 15th are largely uncataloged and have a completely different angular rate distribution than brighter objects. Combining the information obtained for both faint and bright objects yields a more complete picture of the debris environment rather than just concentrating on the faint debris. One objective is to estimate what fraction of objects selected on the basis of angular rate are not at GEO. A second objective is to obtain magnitudes and colors in standard astronomical filters (BVRI) for comparison with reflectance spectra of likely spacecraft materials. This paper reports on results from two 14 night runs with both telescopes: in March and November 2007: (1) A significant fraction of objects fainter than
LHC Orbit Correction Reproducibility and Related Machine Protection
Baer, T; Fuchsberger, K; Schmidt, R; Wenninger, J
2012-01-01
The Large Hadron Collider (LHC) has an unprecedented nominal stored beam energy of up to 362 MJ per beam. In order to ensure an adequate machine protection by the collimation system, a high reproducibility of the beam position at collimators and special elements like the final focus quadrupoles is essential. This is realized by a combination of manual orbit corrections, feed forward and real time feedback. In order to protect the LHC against inconsistent orbit corrections, which could put the...
Hardy's paradox tested in the spin-orbit Hilbert space of single photons
Karimi, Ebrahim; Cardano, Filippo; Maffei, Maria; de Lisio, Corrado; Marrucci, Lorenzo; Boyd, Robert W.; Santamato, Enrico
2014-01-01
We test experimentally the quantum ``paradox'' proposed by Lucien Hardy in 1993 [Phys. Rev. Lett. 71, 1665 (1993)] by using single photons instead of photon pairs. This is achieved by addressing two compatible degrees of freedom of the same particle, namely its spin angular momentum, determined by the photon polarization, and its orbital angular momentum, a property related to the optical transverse mode. Because our experiment involves a single particle, we cannot use locality to logically e...
Energy Technology Data Exchange (ETDEWEB)
Butikov, Eugene I [St Petersburg State University, St Petersburg (Russian Federation)
2003-03-01
Various properties of Keplerian orbits traced by satellites that are launched from one and the same spatial point with different initial velocities are discussed. Two families of elliptical orbits are investigated, namely the sets of orbits produced by a common direction but different magnitudes of the initial velocities, and by a common magnitude but various directions of the initial velocities. For the latter family, the envelope of all the orbits is found, which is the boundary of the spatial region occupied by the orbits.
Butikov, E I
2003-01-01
Various properties of Keplerian orbits traced by satellites that are launched from one and the same spatial point with different initial velocities are discussed. Two families of elliptical orbits are investigated, namely the sets of orbits produced by a common direction but different magnitudes of the initial velocities, and by a common magnitude but various directions of the initial velocities. For the latter family, the envelope of all the orbits is found, which is the boundary of the spatial region occupied by the orbits.
Nutrition environments in corner stores in Philadelphia.
Cavanaugh, Erica; Mallya, Giridhar; Brensinger, Colleen; Tierney, Ann; Glanz, Karen
2013-02-01
To examine the availability, quality, and price of key types of healthy and less-healthy foods found in corner stores in low-income urban neighborhoods and the associations between store characteristics and store food environments. A sample of 246 corner stores was selected from all corner stores participating in the Philadelphia Healthy Corner Store Initiative (HCSI). The Nutrition Environment Measures Survey for Corner Stores (NEMS-CS) was used to assess the availability, quality, and price of foods and beverages in 11 common categories between February and May, 2011. NEMS-CS measures were completed in 233 stores, 94.7% of the 246 stores approached. The healthier options were significantly less available in all food categories and often more expensive. Baked goods, bread, chips and cereals were sold at nearly all stores, with significantly fewer offering low-fat baked goods (5.7%, pstore food environment and dietary choices among low-income urban populations. Availability of certain healthier foods could be improved. Copyright © 2012 Elsevier Inc. All rights reserved.
Photon Self-Induced Spin to Orbital Conversion in TGG crystal at high laser power
Mosca, S; Karimi, E; Piccirillo, B; Marrucci, L; De Rosa, R; Genin, E; Milano, L; Santamato, E
2010-01-01
In this paper, we present experimental evidence of a newly discovered third-order nonlinear optical process Self-Induced Spin-to-Orbital Conversion (SISTOC) of the photon angular momentum. This effect is the physical mechanism at the origin of the depolarization of very intense laser beams propagating in isotropic materials. The SISTOC process, like self-focusing, is triggered by laser heating leading to a radial temperature gradient in the medium. In this work we tested the occurrence of SISTOC in a terbium gallium garnet (TGG) rod for an impinging laser power of about 100~W. To study the SISTOC process we used different techniques: polarization analysis, interferometry and tomography of the photon orbital angular momentum. Our results confirm, in particular, that the apparent depolarization of the beam is due to the occurrence of maximal entanglement between the spin and orbital angular momentum of the photons undergoing the SISTOC process. This explanation of the true nature of the depolarization mechanism...
Spherical angular spectrum and the fractional order Fourier transform.
Pellat-Finet, Pierre; Durand, Pierre-Emmanuel; Fogret, Eric
2006-12-01
The notion of a spherical angular spectrum leads to the decomposition of the field amplitude on a spherical emitter into a sum of spherical waves that converge onto the Fourier sphere of the emitter. Unlike the usual angular spectrum, the spherical angular spectrum is propagated as the field amplitude, in a way that can be expressed by a fractional order Fourier transform.
Directory of Open Access Journals (Sweden)
Jeffrey M Joseph
2011-01-01
Full Text Available Jeffrey M Joseph, Ioannis P GlavasDivision of Ophthalmic Plastic and Reconstructive Surgery, Department of Ophthalmology, School of Medicine, New York University, New York, NY, USA; Manhattan Eye, Ear, and Throat Hospital, New York, NY, USAAbstract: This review of orbital fractures has three goals: 1 to understand the clinically relevant orbital anatomy with regard to periorbital trauma and orbital fractures, 2 to explain how to assess and examine a patient after periorbital trauma, and 3 to understand the medical and surgical management of orbital fractures. The article aims to summarize the evaluation and management of commonly encountered orbital fractures from the ophthalmologic perspective and to provide an overview for all practicing ophthalmologists and ophthalmologists in training.Keywords: orbit, trauma, fracture, orbital floor, medial wall, zygomatic, zygomatic complex, zmc fracture, zygomaticomaxillary complex fractures
1989-07-15
IWORK UNIT ELEMENT NO NO. NO. ACCESSION NO. 11. TITLE (Include Security Classification) UNCLASSIFIED: Aplicacion Del Modelo De Traslape Angular A...Justificatio Aplicacion Del Medelo De Traslape Angular A By Ftalocinaninas De Lantanidos Disributon/ (Application of the Angular Overlap Model to...Control Data - DD Form 1473. Copies of the form are available from the cognizant contract administrator. APLICACION DEL MODELO DE TRASLAPE ANGULAR A
Propagating separable equalities in an MDD store
DEFF Research Database (Denmark)
Hadzic, Tarik; Hooker, John N.; Tiedemann, Peter
2008-01-01
We present a propagator that achieves MDD consistency for a separable equality over an MDD (multivalued decision diagram) store in pseudo-polynomial time. We integrate the propagator into a constraint solver based on an MDD store introduced in [1]. Our experiments show that the new propagator pro...... provides substantial computational advantage over propagation of two inequality constraints, and that the advantage increases when the maximum width of the MDD store increases....
Quantitative grading of store separation trajectories
CSIR Research Space (South Africa)
Jamison, Kevin A
2017-09-01
Full Text Available grading of store separation trajectories Kevin Jamison, Pieter Rossouw & Elizna Miles Council of Scientific and Industrial Research Pretoria, South Africa Ankara International Aerospace Conference September 2017 2 Outline • Background... - MIL-HDBK-244A §5.1.1.2.3.1(g) ; MIL-HDBK 1763: 271.4 – Verify that stores can be released safety over full employment & jettison envelopes • Includes all perturbations of: – store mass and physical properties – ejector rack performance...
Signature-based store checking buffer
Sridharan, Vilas; Gurumurthi, Sudhanva
2015-06-02
A system and method for optimizing redundant output verification, are provided. A hardware-based store fingerprint buffer receives multiple instances of output from multiple instances of computation. The store fingerprint buffer generates a signature from the content included in the multiple instances of output. When a barrier is reached, the store fingerprint buffer uses the signature to verify the content is error-free.
Periodic orbits around a spherically symmetric naked singularity
Babar, Gulmina Zaman; Babar, Adil Zaman; Lim, Yen-Kheng
2017-10-01
The motion of time-like test particles in the Fisher/Janis-Newman-Winicour (F/JNW) spacetime is studied with the Hamiltonian formulation of the geodesic equations. The spacetime is characterized by its mass parameter rg and scalar field parameter ν . The innermost bound and stable circular orbits are calculated and the effective potential is analyzed. Consistent with numerical results in earlier literature, for ν <1/2 , particles with nonzero angular momentum encounter an infinite potential barrier, preventing them from reaching the naked singularity at r =rg. Periodic orbits in the spacetime are also obtained. Compared to the periodic orbits around the Schwarzschild black hole, it is found that typically lower energies are required for the same orbits in the F/JNW spacetime.
Angular momentum evolution in laser-plasma accelerators
Thaury, C; Corde, S; Lehe, R; Bouteiller, M Le; Phuoc, K Ta; Davoine, X; Rax, J -M; Rousse, A; Malka, V
2013-01-01
The transverse properties of an electron beam are characterized by two quantities, the emittance which indicates the electron beam extend in the phase space and the angular momentum which allows for non-planar electron trajectories. Whereas the emittance of electron beams produced in laser- plasma accelerator has been measured in several experiments, their angular momentum has been scarcely studied. It was demonstrated that electrons in laser-plasma accelerator carry some angular momentum, but its origin was not established. Here we identify one source of angular momentum growth and we present experimental results showing that the angular momentum content evolves during the acceleration.
Angular-Momentum Evolution in Laser-Plasma Accelerators
Thaury, Cédric; Corde, Sébastien; Lehe, Rémi; Le Bouteiller, Madeleine; Ta Phuoc, Kim; Davoine, Xavier; Rax, J. M.; Rousse, Antoine; Malka, Victor
2013-01-01
The transverse properties of an electron beam are characterized by two quantities, the emittance which indicates the electron beam extent in the phase space and the angular momentum which allows for non-planar electron trajectories. Whereas the emittance of electron beams produced in laserplasma accelerator has been measured in several experiments, their angular momentum has been scarcely studied. It was demonstrated that electrons in laser-plasma accelerator carry some angular momentum, but its origin was not established. Here we identify one source of angular momentum growth and we present experimental results showing that the angular momentum content evolves during the acceleration.
Store Image: Scale implementation Part 3
Directory of Open Access Journals (Sweden)
Ronel du Preez
2008-11-01
Full Text Available This paper is the final in the three-part series regarding store image. The purposes of this article are to (1 implement the developed scale to assess whether it illustrates acceptable psychometric properties of reliability and validity, (2 assess the model fit of the developed scale and (3 formulate recommendations for future research. Results indicated that the Apparel Store Image Scale (ASIS show acceptable reliability and model fit. A refined definition of store image was proposed together with a Final Model of Apparel Store Image. Recommendations for future research are made.
DEFF Research Database (Denmark)
Hansen, Torben; Cumberland, Flemming; Solgaard, Hans Stubbe
2013-01-01
The influence of distance on consumer store choice behaviour has been considered in many studies. In that respect, frequency and budget share are frequently used methods of measurement to determine the consumer's store choice behavour. In this study, we propose that the significance of distance...... is influenced by the way in which store choice behaviour is conceptualized. A survey among 631 consuemrs was performed in order to examine the research proposition. Structural equation results suggest that the negative effect of distance on store choice behaviour is larger when store choice behaviour...... is measured as number of visits to a particular store than wehen store cjoice behaviour is measured as the percentage of budget spend at a particular store. Our results indicate that researchers should carefully consider the measurement of store choice behaviour when carrying out empirical research invlving...
Measurement of the total optical angular momentum transfer in optical tweezers
Parkin, Simon; Knöner, Gregor; Nieminen, Timo A.; Heckenberg, Norman R.; Rubinsztein-Dunlop, Halina
2006-07-01
We describe a way to determine the total angular momentum, both spin and orbital, transferred to a particle trapped in optical tweezers. As an example an LG02 mode of a laser beam with varying degrees of circular polarisation is used to trap and rotate an elongated particle with a well defined geometry. The method successfully estimates the total optical torque applied to the particle. For this technique, there is no need to measure the viscous drag on the particle, as it is an optical measurement. Therefore, knowledge of the particle’s size and shape, as well as the fluid’s viscosity, is not required.
Orbit Control of Fly-around Satellite with Highly Eccentric Orbit Using Solar Radiation Pressure
Yong-gang, Hou; Chang-yin, Zhao; Ming-jiang, Zhang; Rong-yu, Sun
2017-01-01
The method of controlling highly eccentric accompanying flight orbit using the solar wing is proposed in this paper. The formation is maintained by controlling the orbit of the accompanying satellite (follower). The accompanying satellite rotates around its inertial principal axis with a constant angular velocity. The control on the accompanying satellite is divided into the in-plane control and out-of-plane control. The in-plane control is superior to the out-of-plane control. The out-of-plane control force is applied when the in-plane error is eliminated or the in-plane control force can not be supplied due to some geometrical factors. By the sliding mode control method, the magnitude and direction of the control force required by the in-plane orbit control are calculated. Then accordingly, the expression of the solar wing orientation with respect to the satellite body in the control process is derived, so that by adjusting the orientation of the solar wing, the required control force can be obtained. Finally, the verification on this method is performed by numerical simulations, including the orbit adjustment, error elimination, and the orbit maintenance. It is shown that this method can keep the error less than 5 m, and it is feasible for the space formation flight.
Research on static angular stiffness measurement of flexible joint
Directory of Open Access Journals (Sweden)
Yongchao HUANG
2016-10-01
Full Text Available Measurement accuracy of the angular stiffness of flexible joint is directly related to the control accuracy and sensitivity of gyro, but the traditional measurement methods have many problems. According to the principle of angular stiffness measurement of flexible joint, two static measurement methods of angular stiffness are proposed based on different loading ways, namely mechanical loading angular stiffness measurement and piezoelectric loading angular stiffness measurement. The mechanical loading angular stiffness measurement system is built by using a motor driven indexing feeding tilting table, the measure experiment if the angular stiffness of flexible joint is conducted, and the angular stiffness of flexible joint is measured. For the excessive fluctuation problem of the measure result in mechanical load test, a piezoelectric loading structure is designed and a measurement method employing piezoelectric actuator is proposed for angular stiffness measurement of flexible joint. Based on ANSYS Workbench, the displacement output of the piezoelectric loading structure is analyzed by simulations. The simulation results illustrate that the displacement output meets the requirement of static loading angular stiffness measurement of flexible joint, and the theoretical feasibility of piezoelectric loading angular stiffness measurement method is validated.
Angular Rate Estimation Using a Distributed Set of Accelerometers
Directory of Open Access Journals (Sweden)
Sung Kyung Hong
2011-11-01
Full Text Available A distributed set of accelerometers based on the minimum number of 12 accelerometers allows for computation of the magnitude of angular rate without using the integration operation. However, it is not easy to extract the magnitude of angular rate in the presence of the accelerometer noises, and even worse, it is difficult to determine the direction of a rotation because the angular rate is present in its quadratic form within the inertial measurement system equations. In this paper, an extended Kalman filter scheme to correctly estimate both the direction and magnitude of the angular rate through fusion of the angular acceleration and quadratic form of the angular rate is proposed. We also provide observability analysis for the general distributed accelerometers-based inertial measurement unit, and show that the angular rate can be correctly estimated by general nonlinear state estimators such as an extended Kalman filter, except under certain extreme conditions.
Orbits in Homogeneous Oblate Spheroidal Gravitational Space-Time
Directory of Open Access Journals (Sweden)
Chifu E. N.
2009-07-01
Full Text Available The generalized Lagrangian in general relativistic homogeneous oblate spheroidal gravitational fields is constructed and used to study orbits exterior to homogenous oblate spheroids. Expressions for the conservation of energy and angular momentum for this gravitational field are obtained. The planetary equation of motion and the equation of motion of a photon in the vicinity of an oblate spheroid are derived. These equations have additional terms not found in Schwarzschild's space time.
Optical evidence of quantum rotor orbital excitations in orthorhombic manganites
Kovaleva, N. N.; Kugel, K. I.; Potucek, Z.; Goryachev, N. S.; Kusmartseva, O. E.; Bryknar, Z.; Trepakov, V. A.; Demikhov, E. I.; Dejneka, A.; Kusmartsev, F. V.; Stoneham, A. M.
2014-01-01
In magnetic compounds with Jahn-Teller (JT) ions (such as Mn3+ or Cu2+), the ordering of the electron or hole orbitals is associated with cooperative lattice distortions. There the role of JT effect, although widely recognised, is still elusive in the ground state properties. We suggest that, in these materials, there exist elementary excitations whose energy spectrum is described in terms of the total angular momentum eigenstates and is quantised as in quantum rotors found in JT centers. We ...
Angular correlation studies in noble gases
Coleman, P. G.
1990-01-01
There has been a recent revival of interest in the measurement of angular correlation of annihilation photons from the decay of positrons and positronium in gases. This revival has been stimulated by the possibility offered by the technique to shed new light on the apparently low positronium formation fraction in the heavier noble gases and to provide information on positronium quenching processes in gases such as oxygen. There is also the potential for learning about positronium slowing down in gases. This review focuses on experimental noble gas work and considers what new information has been, and may be, gained from these studies.
Angular momentum sensitive two-center interference.
Ilchen, M; Glaser, L; Scholz, F; Walter, P; Deinert, S; Rothkirch, A; Seltmann, J; Viefhaus, J; Decleva, P; Langer, B; Knie, A; Ehresmann, A; Al-Dossary, O M; Braune, M; Hartmann, G; Meissner, A; Tribedi, L C; AlKhaldi, M; Becker, U
2014-01-17
In quantum mechanics the Young-type double-slit experiment can be performed with electrons either traveling through a double slit or being coherently emitted from two inversion symmetric molecular sites. In the latter one the valence photoionization cross sections of homonuclear diatomic molecules were predicted to oscillate over kinetic energy almost 50 years ago. Beyond the direct proof of the oscillatory behavior of these photoionization cross sections σ, we show that the angular distribution of the emitted electrons reveals hitherto unexplored information on the relative phase shift between the corresponding partial waves through two-center interference patterns.
Angular Distributions of Discrete Mesoscale Mapping Functions
Kroszczyński, Krzysztof
2015-08-01
The paper presents the results of analyses of numerical experiments concerning GPS signal propagation delays in the atmosphere and the discrete mapping functions defined on their basis. The delays were determined using data from the mesoscale non-hydrostatic weather model operated in the Centre of Applied Geomatics, Military University of Technology. A special attention was paid to investigating angular characteristics of GPS slant delays for low angles of elevation. The investigation proved that the temporal and spatial variability of the slant delays depends to a large extent on current weather conditions.
The angular momentum of isolated white dwarfs
Directory of Open Access Journals (Sweden)
Brassard P.
2013-03-01
Full Text Available This is a very brief report on an ongoing program aimed at mapping the internal rotation profiles of stars through asteroseismology. Three years ago, we developed and applied successfully a new technique to the pulsating GW Vir white dwarf PG 1159−035, and were able to infer that it rotates very slowly and rigidly over some 99% of its mass. We applied the same approach to the three other GW Vir pulsators with available rotational splitting data, and found similar results. We discuss the implications of these findings on the question of the angular momentum of white dwarfs resulting from single star evolution.
Projection of angular momentum via linear algebra
Johnson, Calvin W.; O'Mara, Kevin D.
2017-12-01
Projection of many-body states with good angular momentum from an initial state is usually accomplished by a three-dimensional integral. We show how projection can instead be done by solving a straightforward system of linear equations. We demonstrate the method and give sample applications to 48Cr and 60Fe in the p f shell. This new projection scheme, which is competitive against the standard numerical quadrature, should also be applicable to other quantum numbers such as isospin and particle number.
Directory of Open Access Journals (Sweden)
Khalil M Al-Salem
2014-01-01
Full Text Available Orbital complications due to ethmoiditis are rare in neonates. A case of orbital abscess due to acute ethmoiditis in a 28-day-old girl is presented. A Successful outcome was achieved following antimicrobial therapy alone; spontaneous drainage of the abscess occurred from the lower lid without the need for surgery. From this case report, we intend to emphasize on eyelid retraction as a sign of neonatal orbital abscess, and to review all the available literature of similar cases.
Robust interferometer for the routing of light beams carrying orbital angular momentum
CSIR Research Space (South Africa)
Lavery, MPJ
2011-09-01
Full Text Available , piezoelectric; A, output port A; B, output port B and PD, photo-diode). (b) and (c) illustrate the effect of the prisms on their own. It can be seen that the beams behind the two prisms are rotated by 180? with respect to each other. An inverting prism, like... between the two arms in the interferometer of Delta1? = 2lscript? (figure 1(a)). In the specific case of ? = 90?, constructive interference will occur at one of the two output ports for all even lscript-valued states and then for odd lscript...
Poynting vector and orbital angular momentum density of superpositions of Bessel beams
CSIR Research Space (South Africa)
Litvin, IA
2011-08-01
Full Text Available . Experimental methodology A HeNe laser (? ~633 nm) was expanded through a 6 ? telescope and directed onto the liquid crystal display (LCD) of a SLM (HoloEye, PLUTO-VIS, with 1920 ? 1080 pixels of pitch 8 ?m and calibrated for a 2? phase shift at ~633 nm...) depicted in Fig. 1. The first SLM (denoted as LCD 1) was programmed to produce various superposition fields using the concept of Durnin?s ring-slit [31], but implemented digitally [29]. Other techniques to experimentally generate superpositions...
Measuring the orbital angular momentum density for a superposition of Bessel beams
CSIR Research Space (South Africa)
Dudley, Angela L
2012-01-01
Full Text Available the liquid crystal display (LCD) of a SLM. The first SLM (denoted as LCD 1) was programmed to produce various superposition fields using the concept of Durnin?s ring-slit [14], but implemented digitally [15]. Proc. of SPIE Vol. 8274 827406-3 Downloaded... superposition field was then magnified with a 10? objective and directed to the second SLM (LCD 2) for executing the modal decomposition of Eq. (5). The incoming field was divided into 10 annular rings and the phase within each annular ring varied...
Measurement of the orbital angular momentum density of light by modal decomposition
CSIR Research Space (South Africa)
Schulze, C
2013-07-01
Full Text Available measurement according to equation (7) was not necessary. As a first example, a pure Laguerre–Gaussian mode LG0,1 was generated with SLM1, where the last-mentioned index indicates the order of the helical phase and the topological charge [6, 45]. To measure... does not contain any azimuthal phase component. Thus far the investigated beams have been single Laguerre–Gaussian modes. However, even more interesting with regard to the conservation of momentum and topological charge are mode superpositions [45, 46...
High-power Bessel beams with orbital angular momentum in the terahertz range
Choporova, Yu. Yu.; Knyazev, B. A.; Kulipanov, G. N.; Pavelyev, V. S.; Scheglov, M. A.; Vinokurov, N. A.; Volodkin, B. O.; Zhabin, V. N.
2017-08-01
In this paper, we have performed experimental, analytical, and numerical studies of beams with topological charges of ±1 and ±2 formed by silicon binary phase axicons (BPAs) with spiral zone structures. The axicons were illuminated with the Novosibirsk free electron laser radiation (a continuous stream of 100-ps pulses at f =5.6 MHz). The cw power of the beams produced reached 30 W and can by doubled via antireflection coating of the axicons. The intensity distribution in the beam cross sections was in good agreement with the Bessel functions and was kept constant within a distance of about L /r ≈190 and 100, where the first ring radii of the beams r were 0.9 and 1.5 mm for the Bessel beams of the first and second orders, respectively. Although the characteristics of the beams (Bessel cross section, "diffraction-free" propagation, self-recovery after passing obstacles, and randomly inhomogeneous media) corresponded to the properties of ideal Bessel beams, their spatial Fourier spectrum (the image in the focal plane of the lens) was, instead of an ideal ring, intertwined segments of arcs with phases shifted by π , the number of which was equal to the double value of the topological charge. This feature can be used, for example, in a demultiplexing unit of a free vortex-wave communication system or for identification of beam topological charge. We also revisited Young's double-slit diffraction and rotation of beams obstructed by a half-plane, previously applied to Laguerre-Gaussian beam characterization, in the case of the Bessel beams. The Young diffraction pattern demonstrated in this case a complicated intensity-phase distribution. It was shown that the Bessel beams formed by BPAs have two important advantages, which can be used in applications, in comparison with other methods of generation, e.g., a combination of an axicon lens with a spiral phase plate. Although the phase jumps of the axicons are designed for a determined wavelength (141 μ m in our case), the BPAs can form the beams at incident radiation with any wavelength, albeit with a reduced diffraction efficiency, and their cross section is the same for any wavelength.
Violation of a Bell inequality in two-dimensional orbital angular momentum state-spaces
National Research Council Canada - National Science Library
J. Leach; B. Jack; J. Romero; M. Ritsch-Marte; R. W. Boyd; A. K. Jha; S. M. Barnett; S. Franke-Arnold; M. J. Padgett
2009-01-01
...). By drawing a direct analogy between OAM and polarization states of light, we demonstrate the entangled nature of high order OAM states generated by spontaneous downconversion through violation...
DEFF Research Database (Denmark)
Lyubopytov, Vladimir; Porfirev, Alexey P.; Gurbatov, Stanislav O.
2017-01-01
wavelengths, each of them carrying two channels with zero and nonzero OAMs, form four independent information channels. In case of spacing between wavelength channels of 0.8 nm and intensity modulation, power penalties relative to the transmission of one channel do not exceed 1.45, 0.79 and 0.46 d......B at the harddecision forward-error correction (HD-FEC) bit-error-rate (BER) limit 3.8 × 10□3 when multiplexing a Gaussian beam and OAM beams of azimuthal orders 1, 2 and 3 respectively. In case of phase modulation, power penalties do not exceed 1.77, 0.54 and 0.79 dB respectively. At the 0.4 nm wavelength grid......, maximum power penalties at the HD-FEC BER threshold relative to the 0.8 nm wavelength spacing read 0.83, 0.84 and 1.15 dB when multiplexing a Gaussian beam and OAM beams of 1st, 2nd and 3rd orders respectively. The novelty and impact of the proposed filter design is in providing practical, integrable...
Vortex-MEMS filters for wavelength-selective orbital-angular-momentum beam generation
DEFF Research Database (Denmark)
Paul, Sujoy; Lyubopytov, Vladimir; Schumann, Martin F.
2017-01-01
In this paper an on-chip device capable of wavelength-selective generation of vortex beams is demonstrated. The device is realized by integrating a spiral phase-plate onto a MEMS tunable Fabry-Perot filter. This vortex-MEMS filter, being capable of functioning simultaneously in wavelength...
Shape invariant higher-order Bessel-like beams carrying orbital angular momentum
CSIR Research Space (South Africa)
Ismail, Y
2012-09-01
Full Text Available in the near field to an annular ring in the far field. We demonstrate the production of such fields in the laboratory with an optical system comprising a combination of two axicons and a lens, allowing for control of the cone angle of the resulting field...
Zhu, Fuquan; Huang, Sujuan; Shao, Wei; Zhang, Jie; Chen, Musheng; Zhang, Weibing; Zeng, Junzhang
2017-08-01
We experimentally demonstrate a free-space optical communication link using perfect vortex beams. Perfect vortex beams with different topological charges are generated using a phase-modulation-type spatial light modulator (SLM) loaded with novel phase holograms based on the Bessel function. With the help of a microscope objective and simple lens, perfect vortex beams are transmitted effectively for a certain distance. After completing the demodulation of perfect vortex beams carrying OFDM 16-QAM signals and a series of offline processing on the Gaussian bright spot demodulated from the perfect vortex beams, we also achieve a communication link. The constellations and mean bit error rates (BER) of subcarriers are shown.
Orbital angular momentum modes by twisting of a hollow core antiresonant fiber
DEFF Research Database (Denmark)
Stefani, Alessio; Kuhlmey, Boris T.; Fleming, Simon
2017-01-01
physical phenomena [2]. We previously reported the ability to create helical hollow fibers by mechanically twisting a tube lattice fiber made of polyurethane, the twist of which can be adjusted and reversed [3]. In this work we report how such deformation induces a mode transformation to an OAM mode...
Modal decomposition for measuring the orbital angular momentum density of light
CSIR Research Space (South Africa)
Schulze, C
2013-02-01
Full Text Available -5 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 03/14/2013 Terms of Use: http://spiedl.org/terms 10.8 0.6 0.4 0.2 i I 1 0.8 0.6 0.4 0.2 0 x 10-12 5 4 3 2 1 0 -1 -2 Figure 5. Experimental setup for measuring the OAM density of a fiber beam. Nd:YAG... Nd:YAG laser, L lens, M mirror, QWP quarter-wave plate, P polarizer, BS beam splitter, CGH computer-generated hologram, CCD1,2 CCD cameras 4.2 Fiber beams The comparison of the measured OAM densities with the ones expected for the artifically...
Pattern manipulation via on-chip phase modulation between orbital angular momentum beams
Energy Technology Data Exchange (ETDEWEB)
Li, Huanlu [Department of Electrical and Electronic Engineering, University of Bristol, University Walk, Bristol BS8 1TR (United Kingdom); School of Engineering, University of Glasgow, Rankine Building, Oakfield Avenue, Glasgow G12 8LP (United Kingdom); Strain, Michael J. [School of Engineering, University of Glasgow, Rankine Building, Oakfield Avenue, Glasgow G12 8LP (United Kingdom); Wolfson Centre, Institute of Photonics, University of Strathclyde, 106 Rottenrow East, Glasgow G4 0NW (United Kingdom); Meriggi, Laura; Sorel, Marc [School of Engineering, University of Glasgow, Rankine Building, Oakfield Avenue, Glasgow G12 8LP (United Kingdom); Chen, Lifeng; Zhu, Jiangbo; Cicek, Kenan [Department of Electrical and Electronic Engineering, University of Bristol, University Walk, Bristol BS8 1TR (United Kingdom); Wang, Jianwei; Thompson, Mark G. [Centre for Quantum Photonics, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol, Bristol BS8 1UB (United Kingdom); Cai, Xinlun, E-mail: caixlun5@mail.sysu.edu.cn [Centre for Quantum Photonics, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol, Bristol BS8 1UB (United Kingdom); State Key Laboratory of Optoelectronic Materials and Technologies and School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Yu, Siyuan, E-mail: s.yu@bristol.ac.uk [Department of Electrical and Electronic Engineering, University of Bristol, University Walk, Bristol BS8 1TR (United Kingdom); State Key Laboratory of Optoelectronic Materials and Technologies and School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)
2015-08-03
An integrated approach to thermal modulation of relative phase between two optical vortices with opposite chirality has been demonstrated on a silicon-on-insulator substrate. The device consists of a silicon-integrated optical vortex emitter and a phase controlled 3 dB coupler. The relative phase between two optical vortices can be actively modulated on chip by applying a voltage on the integrated heater. The phase shift is shown to be linearly proportional to applied electrical power, and the rotation angle of the interference pattern is observed to be inversely proportional to topological charge. This scheme can be used in lab-on-chip, communications and sensing applications. It can be intentionally implemented with other modulation elements to achieve more complicated applications.
Stored-product insects associated with a retail pet store chain in Kansas.
Roesli, Rennie; Subramanyam, Bhadriraju; Campbell, James F; Kemp, Kim
2003-12-01
The types and numbers of insect species associated with eight Kansas retail stores belonging to a pet store chain were surveyed during February to August 2001. Insects were monitored at 1-3-wk intervals using food- and pheromone-baited pitfall traps for beetles and pheromone-baited sticky traps for moths. Thirty traps of each type were placed within a store. Thirty insect species belonging to 20 families in four orders were recorded from the eight stores. The weevils, Sitophilus spp.; Indianmeal moth, Plodia interpunctella (Hübner); and merchant grain beetle, Oryzaephilus mercator (Fauvel), were the most common and abundant species in all stores, whereas the red-legged ham beetle, Necrobia rufipes (Degeer), and red flour beetle, Tribolium castaneum (Herbst), were abundant only in one store. The numbers of each insect species captured varied from store to store. In each of the stores, a total of 12-19 stored-product species were captured in traps, and seven of the eight stores had relatively high species diversity. With the exception of one store, the different types of insect species found among the remaining seven stores were essentially similar. The mean density of insects in infested bulk-stored and bagged pet food products removed from a store ranged from 65 to 656 adults/kg. The types and numbers of insect species captured in traps indicated that infestations were well established in the surveyed stores. Early detection and management of these infestations is critical for maintaining quality and integrity of food products sold in the pet stores.
Directory of Open Access Journals (Sweden)
Gulden Turhan
2014-01-01
Full Text Available The study’s research model suggests that store design and ease of shopping are associated with customer retention through a mediated pathway in which store design and ease of shopping influence perceived store satisfaction, which in turn, influences customer retention. This survey was administered to two separate clothing stores offered to either females or males (in total, 533 participants. Using structural equation modelling methodology, data was analysed to explain the interrelations among the variables in the model. The results of an empirical study of a sample of store shoppers revealed that store design and ease of shopping influence customer retention in an indirect way through customer perception of satisfaction with the store. In building store satisfaction that is centred on customer retention, store design and shopping ease differ in their relative influences. This difference is high for females, but for men as low as to be considered negligible in males. As a result, improving customers’ perceptions of store design and ease of shopping is a way to ensure store satisfaction support customer retention. The results of the study provide a new insight into the relationships by suggesting indirect effects of shopping ease and store design on consumer retention by their impacts on store satisfaction, rather than direct effects.
Directory of Open Access Journals (Sweden)
Gulden Turhan
2016-01-01
Full Text Available The study’s research model suggests that store design and ease of shopping are associated with customer retention through a mediated pathway in which store design and ease of shopping influence perceived store satisfaction, which in turn, influences customer retention. This survey was administered to two separate clothing stores offered to either females or males (in total, 533 participants. Using structural equation modelling methodology, data was analysed to explain the interrelations among the variables in the model. The results of an empirical study of a sample of store shoppers revealed that store design and ease of shopping influence customer retention in an indirect way through customer perception of satisfaction with the store. In building store satisfaction that is centred on customer retention, store design and shopping ease differ in their relative influences. This difference is high for females, but for men as low as to be considered negligible in males. As a result, improving customers’ perceptions of store design and ease of shopping is a way to ensure store satisfaction support customer retention. The results of the study provide a new insight into the relationships by suggesting indirect effects of shopping ease and store design on consumer retention by their impacts on store satisfaction, rather than direct effects.
2008-01-01
This image shows the paths of three spacecraft currently in orbit around Mars, as well as the path by which NASA's Phoenix Mars Lander will approach and land on the planet. The t-shaped crosses show where the orbiters will be when Phoenix enters the atmosphere, while the x-shaped crosses show their location at landing time. All three orbiters, NASA's Mars Reconnaissance Orbiter, NASA's Mars Odyssey and the European Space Agency's Mars Express, will be monitoring Phoenix during the final steps of its journey to the Red Planet. Phoenix will land just south of Mars's north polar ice cap.
Insect pest management in stored grain
Stored grain is vulnerable to attach by a variety of insect pests, that can generally be classified as external or internal feeders. Infestations primarily occur after grain is stored, though there is some evidence that infestations can occur in the field right before harvest. There are a variety of...
Win-Win Strategies at Discount Stores
B. Deleersnyder (Barbara); M.G. Dekimpe (Marnik); J-B.E.M. Steenkamp (Jan-Benedict); O. Koll (Oliver)
2005-01-01
textabstractAn important development that contributes to store brands’ growing success in the grocery market is the increasing number of discount stores that sell predominantly own, private-label, brands. To fight private labels, manufacturers of national brands feel increasingly compelled to
Compression Debarking of Stored Wood Chips
James A. Mattson
1974-01-01
Two 750 ft. piles of unbarked chips were stored for 1 year to evaluate the effect of chip storage on the effectiveness of bark-chip separations-segregation methods under study. in processing stored chips suffered more wood loss than fresh chips.
Consumers' store choice behavior for fresh food
Meulenberg, M.T.G.; Trijp, van J.C.M.
1991-01-01
Consumers' preference for fresh food stores is analyzed. In particular the choice between supermarkets and specialized shops for purchasing fresh food is analyzed. Attention is given to the factors influencing this choice. For this purpose a number of research questions with respect to store choice
Supramolecular architectures constructed using angular bipyridyl ligands
Barnett, S A
2003-01-01
This work details the synthesis and characterization of a series of coordination frameworks that are formed using bidentate angular N-donor ligands. Pyrimidine was reacted with metal(ll) nitrate salts. Reactions using Cd(NO sub 3) sub 2 receive particular focus and the analogous reactions using the linear ligand, pyrazine, were studied for comparison. In all cases, two-dimensional coordination networks were prepared. Structural diversity is observed for the Cd(ll) centres including metal-nitrate bridging. In contrast, first row transition metal nitrates form isostructural one-dimensional chains with only the bridging N-donor ligands generating polymeric propagation. The angular ligand, 2,4-bis(4-pyridyl)-1,3,5-triazine (dpt), was reacted with Cd(NO sub 3) sub 2 and Zn(NO sub 3) sub 2. Whereas Zn(NO sub 3) sub 2 compounds exhibit solvent mediated polymorphism, a range of structures were obtained for the reactions with Cd(NO sub 3) sub 2 , including the first example of a doubly parallel interpenetrated 4.8 sup...
The Cosmology Large Angular Scale Surveyor (CLASS)
Xu, Zhilei; CLASS Collaboration
2018-01-01
The Cosmology Large Angular Scale Surveyor (CLASS) is an array of telescopes that observe Cosmic Microwave Background (CMB) polarization over ~65% of the sky from the Atacama Desert, Chile in frequency bands at 40 GHz, 90 GHz, 150 GHz, and 220 GHz. Multi-frequency observation enables CLASS to distinguish CMB from galactic foregrounds. CLASS is making large angular scale CMB polarization measurements as part of a five-year survey that will constrain the tensor-to-scalar ratio at the 0.01 level by measuring both the reionization and recombination peaks. CLASS will measure the optical depth to last scattering to near the cosmic variance limit, significantly improving on current constraints. Combining the CLASS optical depth measurement with higher resolution data will improve constraints on the sum of neutrino masses. CLASS will also provide the deepest wide-sky-area Galactic microwave polarization maps for Galactic studies. CLASS has been observing for over one year at 40 GHz frequency band. In my talk, I will introduce the science, design, and current status of the CLASS experiment.
The Cosmology Large Angular Scale Surveyor (CLASS)
Cleary, Joseph
2018-01-01
The Cosmology Large Angular Scale Surveyor (CLASS) is an array of four telescopes designed to measure the polarization of the Cosmic Microwave Background. CLASS aims to detect the B-mode polarization from primordial gravitational waves predicted by cosmic inflation theory, as well as the imprint left by reionization upon the CMB E-mode polarization. This will be achieved through a combination of observing strategy and state-of-the-art instrumentation. CLASS is observing 70% of the sky to characterize the CMB at large angular scales, which will measure the entire CMB power spectrum from the reionization peak to the recombination peak. The four telescopes operate at frequencies of 38, 93, 145, and 217 GHz, in order to estimate Galactic synchrotron and dust foregrounds while avoiding atmospheric absorption. CLASS employs rapid polarization modulation to overcome atmospheric and instrumental noise. Polarization sensitive cryogenic detectors with low noise levels provide CLASS the sensitivity required to constrain the tensor-to-scalar ratio down to levels of r ~ 0.01 while also measuring the optical depth the reionization to sample-variance levels. These improved constraints on the optical depth to reionization are required to pin down the mass of neutrinos from complementary cosmological data. CLASS has completed a year of observations at 38 GHz and is in the process of deploying the rest of the telescope array. This poster provides an overview and update on the CLASS science, hardware and survey operations.
Fast diffusion imaging with high angular resolution.
Chao, Tzu-Cheng; Chiou, Jr-Yuan George; Maier, Stephan E; Madore, Bruno
2017-02-01
High angular resolution diffusion imaging (HARDI) is a well-established method to help reveal the architecture of nerve bundles, but long scan times and geometric distortions inherent to echo planar imaging (EPI) have limited its integration into clinical protocols. A fast imaging method is proposed here that combines accelerated multishot diffusion imaging (AMDI), multiplexed sensitivity encoding (MUSE), and crossing fiber angular resolution of intravoxel structure (CFARI) to reduce spatial distortions and reduce total scan time. A multishot EPI sequence was used to improve geometrical fidelity as compared to a single-shot EPI acquisition, and acceleration in both k-space and diffusion sampling enabled reductions in scan time. The method is regularized and self-navigated for motion correction. Seven volunteers were scanned in this study, including four with volumetric whole brain acquisitions. The average similarity of microstructural orientations between undersampled datasets and their fully sampled counterparts was above 85%, with scan times below 5 min for whole-brain acquisitions. Up to 2.7-fold scan time acceleration along with four-fold distortion reduction was achieved. The proposed imaging strategy can generate HARDI results with relatively good geometrical fidelity and low scan duration, which may help facilitate the transition of HARDI from a successful research tool to a practical clinical one. Magn Reson Med 77:696-706, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.
Sexual health promotion and adult retail stores.
Reece, Michael; Herbenick, Debby; Sherwood-Puzzello, Catherine
2004-05-01
To explore the extent to which adult retail stores may contribute to a community's sexual health promotion infrastructure, we collected data from 294 customer service employees of 80 adult retail stores in 61 U.S. cities. Findings indicated that these stores and their employees do possess at least a baseline level of characteristics that indicate they are serving, or have the potential to serve, as sexual health resources in their communities. As researchers and practitioners continue to explore new and effective mechanisms for responding to sexual health issues, they should consider outlets such as adult stores. Enhancing the capacity of these stores to contribute to sexual health may require strategic collaborations between sexual health researchers, sexual health practitioners, and the adult retail industry in order to develop initiatives that are responsive to the unique goals and cultures of each. Copyright The American Society of Gene Therapy
Endoplasmic reticulum calcium stores in dendritic spines.
Segal, Menahem; Korkotian, Eduard
2014-01-01
Despite decades of research, the role of calcium stores in dendritic spines structure, function and plasticity is still debated. The reasons for this may have to do with the multitude of overlapping calcium handling machineries in the neuron, including stores, voltage and ligand gated channels, pumps and transporters. Also, different cells in the brain are endowed with calcium stores that are activated by different receptor types, and their differential compartmentalization in dendrites, spines and presynaptic terminals complicates their analysis. In the present review we address several key issues, including the role of calcium stores in synaptic plasticity, their role during development, in stress and in neurodegenerative diseases. Apparently, there is increasing evidence for a crucial role of calcium stores, especially of the ryanodine species, in synaptic plasticity and neuronal survival.
Store-operate-coherence-on-value
Chen, Dong; Heidelberger, Philip; Kumar, Sameer; Ohmacht, Martin; Steinmacher-Burow, Burkhard
2014-11-18
A system, method and computer program product for performing various store-operate instructions in a parallel computing environment that includes a plurality of processors and at least one cache memory device. A queue in the system receives, from a processor, a store-operate instruction that specifies under which condition a cache coherence operation is to be invoked. A hardware unit in the system runs the received store-operate instruction. The hardware unit evaluates whether a result of the running the received store-operate instruction satisfies the condition. The hardware unit invokes a cache coherence operation on a cache memory address associated with the received store-operate instruction if the result satisfies the condition. Otherwise, the hardware unit does not invoke the cache coherence operation on the cache memory device.
Critique of the angular momentum sum rules and a new angular momentum sum rule
Bakker, B.L.G.; Leader, E.; Trueman, T. L.
2004-01-01
We present a study of the tensorial structure of the hadronic matrix elements of the angular momentum operators J. Well known results in the literature are shown to be incorrect, and we have taken pains to derive the correct expressions in three different ways, two involving explicit physical wave
Using a Virtual Store As a Research Tool to Investigate Consumer In-store Behavior.
Ploydanai, Kunalai; van den Puttelaar, Jos; van Herpen, Erica; van Trijp, Hans
2017-07-24
People's responses to products and/or choice environments are crucial to understanding in-store consumer behaviors. Currently, there are various approaches (e.g., surveys or laboratory settings) to study in-store behaviors, but the external validity of these is limited by their poor capability to resemble realistic choice environments. In addition, building a real store to meet experimental conditions while controlling for undesirable effects is costly and highly difficult. A virtual store developed by virtual reality techniques potentially transcends these limitations by offering the simulation of a 3D virtual store environment in a realistic, flexible, and cost-efficient way. In particular, a virtual store interactively allows consumers (participants) to experience and interact with objects in a tightly controlled yet realistic setting. This paper presents the key elements of using a desktop virtual store to study in-store consumer behavior. Descriptions of the protocol steps to: 1) build the experimental store, 2) prepare the data management program, 3) run the virtual store experiment, and 4) organize and export data from the data management program are presented. The virtual store enables participants to navigate through the store, choose a product from alternatives, and select or return products. Moreover, consumer-related shopping behaviors (e.g., shopping time, walking speed, and number and type of products examined and bought) can also be collected. The protocol is illustrated with an example of a store layout experiment showing that shelf length and shelf orientation influence shopping- and movement-related behaviors. This demonstrates that the use of a virtual store facilitates the study of consumer responses. The virtual store can be especially helpful when examining factors that are costly or difficult to change in real life (e.g., overall store layout), products that are not presently available in the market, and routinized behaviors in familiar
Lux in obscuro II: photon orbits of extremal AdS black holes revisited
Tang, Zi-Yu; Ong, Yen Chin; Wang, Bin
2017-12-01
A large class of spherically symmetric static extremal black hole spacetimes possesses a stable null photon sphere on their horizons. For the extremal Kerr-Newman family, the photon sphere only really coincides with the horizon in the sense clarified by Doran. The condition under which a photon orbit is stable on an asymptotically flat extremal Kerr-Newman black hole horizon has recently been clarified; it is found that a sufficiently large angular momentum destabilizes the photon orbit, whereas an electrical charge tends to stabilize it. We investigated the effect of a negative cosmological constant on this observation, and found the same behavior in the case of extremal asymptotically Kerr-Newman-AdS black holes in (3+1) -dimensions. In (2+1) -dimensions, in the presence of an electrical charge, the angular momentum never becomes large enough to destabilize the photon orbit. We comment on the instabilities of black hole spacetimes with a stable photon orbit.
A NEW CONFIGURATION OF MODERN TRADE? DEPARTMENT STORES VERSUS VARIETY STORES
Lucian Belascu
2009-01-01
The department store and the variety store are the oldest kinds of unspecialized stores in the modern commercial landscape. They have gone through several development stages starting by middle 19th century. Although different as market position and strategy, sometimes their evolutions intersected, influencing one another and determining changes in their individual policies.
Gijsbrechts, E.; Campo, K.; Nisol, P.
2013-01-01
Grocery-store switching has typically been viewed as evidence of cherry-picking behavior, with consumers switching stores to benefit from temporary promotional offers. However, research reveals that it may also result from a longer-term planning process based on stable store characteristics. Even in
Orbital ordering and frustrations
Khomskii, D.I.; Mostovoy, M.V.
2003-01-01
Orbital ordering occurs in many transition metal compounds with Jahn–Teller ions (Cu2+, Mn3+, low-spin Ni3+, Ti3+ etc). It plays an important role in these materials. At the same time, exchange interactions in orbitally degenerate systems are inherently frustrated, even in materials with simple
African Journals Online (AJOL)
commenced on topical chloramphenicol therapy. The x-ray showed a left orbital soft tissue mass but no orbital enlargement and the swab showed no growth. ... proliferating neural bundles and some neural bundles lined by pigmented choroidal epithelium. Also seen are abundant fibrous tissues scattered within the.
Hara, Yasuo
1975-01-01
Peripheral orbit model, in which an incoming hadron is assumed to revolve in a peripheral orbit around a target hadron, is discussed. The non-diffractive parts of two-body reaction amplitudes of hadrons are expressed in terms of the radius, width an absorptivity of the orbit. The radius of the orbit is about 1 fm and the width of the orbit is determined by the range of the interaction between the hadrons. The model reproduces all available experimental data on differential cross-sections and polarizations of $K^{-}p\\to K^{-}p$ and $\\bar K^{\\circ}n$ reactions for all angles successfully. This contribution is not included in the proceedings since it will appear in Progress of Theoretical Physics Vol. 51 (1974) No 2. Any person interested in the subject may apply for reprints to the author.
Photometric Studies of GEO Orbital Debris
Seitzer, Patrick; Rodriquez-Cowardin, Heather M.; Barker, Ed; Abercromby, Kira J.; Foreman, Gary; Horstman, Matt
2009-01-01
The photometric signature of a debris object can be useful in determining what the physical characteristics of a piece of debris are. We report on optical observations in multiple filters of debris at geosynchronous Earth orbit (GEO). Our sample is taken from GEO objects discovered in a survey with the University of Michigan's 0.6-m aperture Schmidt telescope MODEST (for Michigan Orbital DEbris Survey Telescope), and then followed up in real-time with the Cerro Tololo Inter- American Observatory (CTIO) 0.9-m for orbits and photometry. Our goal is to determine 6 parameter orbits and measure colors for all objects fainter than R=15th magnitude that are discovered in the MODEST survey. At this magnitude the distribution of observed angular rates changes significantly from that of brighter objects. There are two objectives: 1. Estimate the orbital distribution of objects selected on the basis of two observational criteria: brightness (magnitude) and angular rates. 2. Obtain magnitudes and colors in standard astronomical filters (BVRI) for comparison with reflectance spectra of likely spacecraft materials. What is the faint debris likely to be? More than 90 calibrated sequences of R-B-V-I-R magnitudes for a sample of 50 objects have been obtained with the CTIO 0.9-m. For objects that do not show large brightness variations, the colors are largely redder than solar in both B-R and R-I. The width of the color distribution may be intrinsic to the nature of the surfaces, but also could be that we are seeing irregularly shaped objects and measuring the colors at different times with just one telescope. For a smaller sample of objects we have observed with synchronized CCD cameras on the two telescopes. The CTIO 0.9-m observes in B, and MODEST in R. The CCD cameras are electronically linked together so that the start time and duration of observations are the same to better than 50 milliseconds. Thus the B-R color is a true measure of the surface of the debris piece facing the
Gyroscope precession along bound equatorial plane orbits around a Kerr black hole
Bini, Donato; Jantzen, Robert T
2016-01-01
The precession of a test gyroscope along stable bound equatorial plane orbits around a Kerr black hole is analyzed and the precession angular velocity of the gyro's parallel transported spin vector and the increment in precession angle after one orbital period is evaluated. The parallel transported Marck frame which enters this discussion is shown to have an elegant geometrical explanation in terms of the electric and magnetic parts of the Killing-Yano 2-form and a Wigner rotation effect.
Black, Christina; Ntani, Georgia; Inskip, Hazel; Cooper, Cyrus; Cummins, Steven; Moon, Graham; Baird, Janis
2014-05-23
The consumer nutrition environment has been conceptualised as in-store environmental factors that influence food shopping habits. More healthful in-store environments could be characterised as those which promote healthful food choices such as selling good quality healthy foods or placing them in prominent locations to prompt purchasing. Research measuring the full-range of in-store environmental factors concurrently is limited. To develop a summary score of 'healthfulness' composed of nine in-store factors that influence food shopping behaviour, and to assess this score by store type and neighbourhood deprivation. A cross-sectional survey of 601 retail food stores, including supermarkets, grocery stores and convenience stores, was completed in Hampshire, United Kingdom between July 2010 and June 2011. The survey measured nine variables (variety, price, quality, promotions, shelf placement, store placement, nutrition information, healthier alternatives and single fruit sale) to assess the healthfulness of retail food stores on seven healthy and five less healthy foods that are markers of diet quality. Four steps were completed to create nine individual variable scores and another three to create an overall score of healthfulness for each store. Analysis of variance showed strong evidence of a difference in overall healthfulness by store type (p stores offered less healthful environments to consumers however there was variation across the healthfulness spectrum. No relationship between overall healthfulness and neighbourhood deprivation was observed (p = 0.1). A new composite measure of nine variables that can influence food choices was developed to provide an overall assessment of the healthfulness of retail food stores. This composite score could be useful in future research to measure the relationship between main food store and quality of diet, and to evaluate the effects of multi-component food environment interventions.
Untangling Galaxy Components - The Angular Momentum Parameter
Tabor, Martha; Merrifield, Michael; Aragon-Salamanca, Alfonso
2017-06-01
We have developed a new technique to decompose Integral Field spectral data cubes into separate bulge and disk components, allowing us to study the kinematic and stellar population properties of the individual components and how they vary with position. We present here the application of this method to a sample of fast rotator early type galaxies from the MaNGA integral field survey, and demonstrate how it can be used to explore key properties of the individual components. By extracting ages, metallicities and the angular momentum parameter lambda of the bulges and disks, we show how this method can give us new insights into the underlying structure of the galaxies and discuss what this can tell us about their evolution history.
Angular filter refractometry analysis using simulated annealing.
Angland, P; Haberberger, D; Ivancic, S T; Froula, D H
2017-10-01
Angular filter refractometry (AFR) is a novel technique used to characterize the density profiles of laser-produced, long-scale-length plasmas [Haberberger et al., Phys. Plasmas 21, 056304 (2014)]. A new method of analysis for AFR images was developed using an annealing algorithm to iteratively converge upon a solution. A synthetic AFR image is constructed by a user-defined density profile described by eight parameters, and the algorithm systematically alters the parameters until the comparison is optimized. The optimization and statistical uncertainty calculation is based on the minimization of the χ(2) test statistic. The algorithm was successfully applied to experimental data of plasma expanding from a flat, laser-irradiated target, resulting in an average uncertainty in the density profile of 5%-20% in the region of interest.
Mean angular momenta in heavy ion fusion
Energy Technology Data Exchange (ETDEWEB)
Ackermann, D. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, 35020 Legnaro (Padova) (Italy); Scarlassara, F. [Dipartimento di Fisica, Universita di Padova and Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova (Italy); Bednarczyk, P. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, 35020 Legnaro (Padova) (Italy); Beghini, S. [Dipartimento di Fisica, Universita di Padova and Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova (Italy); Corradi, L. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, 35020 Legnaro (Padova) (Italy); Montagnoli, G. [Dipartimento di Fisica, Universita di Padova and Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova (Italy); Mueller, L. [Dipartimento di Fisica, Universita di Padova and Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova (Italy); Napoli, D.R. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, 35020 Legnaro (Padova) (Italy); Petrache, C.M. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, 35020 Legnaro (Padova) (Italy); Varier, K.M. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, 35020 Legnaro (Padova) (Italy); Soramel, F. [Dipartimento di Fisica, Universita di Udine, Udine (Italy); Spolaore, P. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, 35020 Legnaro (Padova) (Italy); Stefanini, A.M. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, 35020 Legnaro (Padova) (Italy); Segato, G.F. [Dipartimento di Fisica, Universita di Padova and Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova (Italy); Signorini, C. [Dipartimento di Fisica, Universita di Padova and Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova (Italy); Zhang, H. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, 35020 Legnaro (Padova) (Italy)
1995-02-06
The results of the measurement of fusion cross sections {sigma}{sub fus} and mean angular momenta left angle l right angle for the five systems {sup 16}O+{sup 112}Cd, {sup 28}Si+{sup 94,100}Mo and {sup 58,64}Ni+{sup 64}Ni are reported. The direct comparison between the fusion excitation function and left angle l right angle (E) confirms consistency of the two independent observables. By analyzing the data in the framework of the coupled channels (CC) approach a good overall agreement between experiment and model predictions has been found. In particular the influence of 2n-transfer channels with positive Q-values is put in evidence. ((orig.)).
Coherent control of photoelectron wavepacket angular interferograms
Hockett, P.; Wollenhaupt, M.; Baumert, T.
2015-11-01
Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process, where the final (time-integrated) observable coherently samples all instantaneous states of the light-matter interaction. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the coherent control over the resultant photoelectron interferogram is thus explored in detail. Based on this understanding, the use of coherent control with polarization-shaped pulses as a methodology for a highly multiplexed coherent quantum metrology is also investigated, and defined in terms of the information content of the observable.
Angular size-redshift: Experiment and calculation
Amirkhanyan, V. R.
2014-10-01
In this paper the next attempt is made to clarify the nature of the Euclidean behavior of the boundary in the angular size-redshift cosmological test. It is shown experimentally that this can be explained by the selection determined by anisotropic morphology and anisotropic radiation of extended radio sources. A catalogue of extended radio sources with minimal flux densities of about 0.01 Jy at 1.4 GHz was compiled for conducting the test. Without the assumption of their size evolution, the agreement between the experiment and calculation was obtained both in the ΛCDM model (Ω m = 0.27, Ω v = 0.73) and the Friedman model (Ω = 0.1).
Cierre angular primario: opciones quirúrgicas
Directory of Open Access Journals (Sweden)
Henry Pérez-González
2014-10-01
Full Text Available Se realizó una revisión bibliográfica con el objetivo de exponer las principales opciones quirúrgicas en el tratamiento del cierre angular primario efectuando una búsqueda de los principales artículos científicos de los últimos años, así como de la literatura impresa que incluye el tema, siendo seleccionados los contenidos más relevantes para la confección del informe final. Las opciones de tratamiento incluyen la cirugía láser (iridotomía, iridoplastia y la cirugía incisional (filtrante, extracción del cristalino, dependiendo de los factores fisiopatológicos involucrados y la forma clínica en el momento del diagnóstico.
Angular filter refractometry analysis using simulated annealing
Angland, P.; Haberberger, D.; Ivancic, S. T.; Froula, D. H.
2017-10-01
Angular filter refractometry (AFR) is a novel technique used to characterize the density profiles of laser-produced, long-scale-length plasmas [Haberberger et al., Phys. Plasmas 21, 056304 (2014)]. A new method of analysis for AFR images was developed using an annealing algorithm to iteratively converge upon a solution. A synthetic AFR image is constructed by a user-defined density profile described by eight parameters, and the algorithm systematically alters the parameters until the comparison is optimized. The optimization and statistical uncertainty calculation is based on the minimization of the χ2 test statistic. The algorithm was successfully applied to experimental data of plasma expanding from a flat, laser-irradiated target, resulting in an average uncertainty in the density profile of 5%-20% in the region of interest.
Coherent Control of Photoelectron Wavepacket Angular Interferograms
Hockett, Paul; Baumert, Thomas
2015-01-01
Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the coherent control over the resultant photoelectron interferogram is thus explored in detail. Based on this understanding, the use of coherent control with polarization-shaped pulses as a methodology for a highly multiplexed coherent quantum metrology is also investigated, and defined in terms of the information content of the observable.
Role of acidic stores in secretory epithelia.
Gerasimenko, Julia; Peng, Shuang; Gerasimenko, Oleg
2014-06-01
There is growing evidence that intracellular calcium plays a primary role in the pathophysiology of the pancreas in addition to its crucial importance in major physiological functions. Pancreatic acinar cells have a remarkably large amount of Ca(2+) stored in both the endoplasmic reticulum (ER) and the acidic stores. The vast majority of the classical ER Ca(2+) store is located in the basal part of the acinar cells with extensions protruding into the apical area, however, the acidic stores are exclusively located in the secretory granular area of the cells. Both types of Ca(2+) store respond to all three intracellular Ca(2+) messengers - inositol trisphosphate (InsP3), cyclic-ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP). The two stores interact with each other via calcium-induced calcium release; however, they can be separated using pharmacological tools. The ER relies on sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) that can be blocked by the specific inhibitor thapsigargin. The acidic store requires a low pH that can be modified by blocking vacuolar H(+)-ATPase. The acidic store is particularly important for pathological processes in the pancreas. Acute pancreatitis is initiated as a result of calcium overload in the apical pole, which leads to trypsinogen activation; two major causes are gall bladder stones and excessive alcohol consumption. Excessive Ca(2+) release from the acidic stores plays a major role in both scenarios; however NAADP-induced calcium release from acidic stores is particularly important for bile-induced pancreatitis. Cell-permeable calmodulin (CaM) activators such as CALP3 boost the natural protective effect of CaM by inhibiting excessive calcium release from the internal stores through inositol trisphosphate (InsP3R) and ryanodine receptors (RyR). Alternatively calcium overload can be dramatically reduced by inhibiting Ca(2+)-release-activated Ca(2+) (CRAC) currents that are required to reload the
Angular Position Tracking Control of a Quadcopter
Directory of Open Access Journals (Sweden)
T. V. Glazkov
2017-01-01
Full Text Available The paper dwells on tracking the quad-copter angular position with desired quality parameters of transient processes. The aerial vehicle is considered as a rigid body with six degrees of freedom. A full rigid body quad-copter mathematical model is considered without the assumption of smallness of the Euler angles.Among the most well known methods of non-linear stabilization are feedback linearization and backstepping. The backstepping approach allows us to have an effective solution of the stabilization problems with uncertainties available in the system. However, in synthesis of the feedback through backstepping, there is still an urgent issue: how to ensure desirable quality of transients in the closed-loop system. The paper presents a solution of this problem using as an example the tracking a given (programmed change of the angular position of a quad-copter.The control algorithms obtained in this paper are implemented using the Rolling Spider MATLAB Toolbox (ROSMAT tool package on the Parrot Rolling Spider quad-copter. A numerical simulation and experiments have shown the efficiency of obtained control laws, with the transient processes taking into account the desired quality indicators. However, the experiments showed that lack of terms in the mathematical model to describe the aerodynamic effects, resulted in the instability of the quad-copter flight near the obstacle (the effect of the reflected airflow.Further research can be aimed at solving the control problem in question using a mathematical model of the quad-copter motion that takes into account various aerodynamic effects.One of the potential application areas for the theoretical results, obtained in the paper, is to solve the problems of automatic control of unmanned aerial vehicles.
Angular Approach Scanning Ion Conductance Microscopy.
Shevchuk, Andrew; Tokar, Sergiy; Gopal, Sahana; Sanchez-Alonso, Jose L; Tarasov, Andrei I; Vélez-Ortega, A Catalina; Chiappini, Ciro; Rorsman, Patrik; Stevens, Molly M; Gorelik, Julia; Frolenkov, Gregory I; Klenerman, David; Korchev, Yuri E
2016-05-24
Scanning ion conductance microscopy (SICM) is a super-resolution live imaging technique that uses a glass nanopipette as an imaging probe to produce three-dimensional (3D) images of cell surface. SICM can be used to analyze cell morphology at nanoscale, follow membrane dynamics, precisely position an imaging nanopipette close to a structure of interest, and use it to obtain ion channel recordings or locally apply stimuli or drugs. Practical implementations of these SICM advantages, however, are often complicated due to the limitations of currently available SICM systems that inherited their design from other scanning probe microscopes in which the scan assembly is placed right above the specimen. Such arrangement makes the setting of optimal illumination necessary for phase contrast or the use of high magnification upright optics difficult. Here, we describe the designs that allow mounting SICM scan head on a standard patch-clamp micromanipulator and imaging the sample at an adjustable approach angle. This angle could be as shallow as the approach angle of a patch-clamp pipette between a water immersion objective and the specimen. Using this angular approach SICM, we obtained topographical images of cells grown on nontransparent nanoneedle arrays, of islets of Langerhans, and of hippocampal neurons under upright optical microscope. We also imaged previously inaccessible areas of cells such as the side surfaces of the hair cell stereocilia and the intercalated disks of isolated cardiac myocytes, and performed targeted patch-clamp recordings from the latter. Thus, our new, to our knowledge, angular approach SICM allows imaging of living cells on nontransparent substrates and a seamless integration with most patch-clamp setups on either inverted or upright microscopes, which would facilitate research in cell biophysics and physiology. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.
... you. A computer creates separate images of the body area, called slices. These images can be stored, viewed on a monitor, or printed on film. The computer can create three-dimensional models of ...
Angular dynamics of small crystals in viscous flow
Fries, J.; Einarsson, J.; Mehlig, B.
2017-01-01
The angular dynamics of a very small ellipsoidal particle in a viscous flow decouples from its translational dynamics and the particle angular velocity is given by Jeffery's theory. It is known that cuboid particles share these properties. In the literature a special case is most frequently discussed, namely that of axisymmetric particles with a continuous rotation symmetry. Here we compute the angular dynamics of crystals that possess a discrete rotation symmetry and certain mirror symmetries but do not have a continuous rotation symmetry. We give examples of such particles that nevertheless obey Jeffery's theory. However, there are other examples where the angular dynamics is determined by a more general equation of motion.
CLARREO Observation Modes and Their Impact on Orbit Definition and On-Orbit Operations
Speth, P. W.; Roithmayr, C.; Macdonnell, D.
2009-12-01
The selection of an optimal orbit and definition of acheivable on-orbit operations is critical to CLARREO's ability to produce irrefutable climate records. The foundation of such a product is the use of exacting on-board traceability of the instrument accuracy. Spectral visible and infrared radiances and GPS Radio Occultation (GPSRO) refractivities measured by CLARREO will be used to detect climate trends and to test, validate, and improve climate prediction models. Through a suite of developed computer programs, assessments of the various instrument modes has been performed to choose the orbits in which to place two CLARREO spacecraft, in preparation for a Mission Concept Review. Intercalibration opportunities between CLARREO and other spacecraft making measurements of reflected solar and infra-red radiation has been performed. The tools take into account idealized orbital dynamics of the two spacecraft, and identifies instances in which the measurements from both platforms satisfy temporal, spatial, and solar illumination constraints. In particular, measurements must be obtained within 5 minutes of each other. The difference in the two viewing zenith angles must be within 1 deg. In the case of reflected solar measurements, the difference in the two relative azimuth angles must be within 1 deg, and the solar zenith angle to each spacecraft must be within 75 deg. The software provides time histories of the two gimbal angles and angular speeds needed for the reflected solar instrument to track chosen Earth-fixed targets.
Orbit Stabilization of Nanosat
Energy Technology Data Exchange (ETDEWEB)
JOHNSON,DAVID J.
1999-12-01
An algorithm is developed to control a pulsed {Delta}V thruster on a small satellite to allow it to fly in formation with a host satellite undergoing time dependent atmospheric drag deceleration. The algorithm uses four short thrusts per orbit to correct for differences in the average radii of the satellites due to differences in drag and one thrust to symmetrize the orbits. The radial difference between the orbits is the only input to the algorithm. The algorithm automatically stabilizes the orbits after ejection and includes provisions to allow azimuthal positional changes by modifying the drag compensation pulses. The algorithm gives radial and azimuthal deadbands of 50 cm and 3 m for a radial measurement accuracy of {+-} 5 cm and {+-} 60% period variation in the drag coefficient of the host. Approaches to further reduce the deadbands are described. The methodology of establishing a stable orbit after ejection is illustrated in an appendix. The results show the optimum ejection angle to minimize stabilization thrust is upward at 86{sup o} from the orbital velocity. At this angle the stabilization velocity that must be supplied by the thruster is half the ejection velocity. An ejection velocity of 0.02 m/sat 86{sup o} gives an azimuthal separation after ejection and orbit stabilization of 187 m. A description of liquid based gas thrusters suitable for the satellite control is included in an appendix.
Orbital cellulitis in children.
Nageswaran, Savithri; Woods, Charles R; Benjamin, Daniel K; Givner, Laurence B; Shetty, Avinash K
2006-08-01
To review the epidemiology and management of orbital cellulitis in children. The medical records of children orbital cellulitis and confirmed by computed tomography scan were reviewed. A literature search for additional studies for systematic review was also conducted. Forty-one children with orbital cellulitis were identified. The mean age was 7.5 years (range, 10 months to 16 years), and 30 (73%) were male (male:female ratio = 2.7). All cases of orbital cellulitis were associated with sinusitis; ethmoid sinusitis was present in 40 (98%) patients. Proptosis and/or ophthalmoplegia was documented in 30 (73%), and 34 (83%) had subperiosteal and/or orbital abscesses. Twenty-nine (71%) had surgical drainage and 12 (29%) received antibiotic therapy only. The mean duration of hospitalization was 5.8 days. The mean duration of antibiotic therapy was 21 days. Orbital cellulitis occurs throughout childhood and in similar frequency among younger and older children. It is twice as common among males as females. Selected cases of orbital cellulitis, including many with subperiosteal abscess, can be treated successfully without surgical drainage.
Human Resources Operational Data Store Core Services
Social Security Administration — This database contains only a very small subset of the Human Resources Operational Data Store data. It supports the SSA Employee and Office Data Retrieval (SEODR)...
Why Store Brand Penetration Varies by Retailer
Sanjay K. Dhar; Hoch, Stephen J
1997-01-01
Our objective in this paper is to explain across-retailer variation in private label performance. Although retailers have lots to gain by better understanding the determinants of successful store brand programs, this knowledge also is very valuable to manufacturers. Lessons learned from competing with other national brands may not transfer one-to-one to the store brand case because, quite simply, a popular private label program changes the status of the retailer from being solely a customer t...
Quantitative grading of store separation trajectories
CSIR Research Space (South Africa)
Jamison, Kevin A
2017-09-01
Full Text Available Aerospace Conference 9th ANKARA INTERNATIONAL AEROSPACE CONFERENCE AIAC-2017-153 20-22 September 2017 - METU, Ankara TURKEY QUANTITATIVE GRADING OF STORE SEPARATION TRAJECTORIES Kevin Jamison1, Pieter Rossouw2 and Elizna... task grows when compliance is required with the MIL-HDBK-244A §5.1.1.2.3.1(g) requirement that all reasonable perturbations of store mass and physical properties, ejector rack 1 Principal...
Tokugawa, J; Nakao, Y; Mori, K; Maeda, M
2003-07-01
A 64-year-old woman presented with a 6-month history of exophthalmus of her right eye. She had no neurological deficit except for the exophthalmus and numbness in the right side of her forehead (frontal nerve territory). Neuro-imaging demonstrated a cystic mass in the right orbit. The tumour was totally removed by microsurgical transcranial surgery. The histological diagnosis was neurinoma. The origin of the tumour was considered to be the frontal nerve. Only two other cases of orbital cystic neurinoma have been reported. This rare clinical entity should be included in the differential diagnosis of a cystic mass in the orbit.
Blanco, Philip R.; Mungan, Carl E.
2016-07-01
Starting with conservation of energy and angular momentum, we derive a convenient method for determining the periapsis distance of an orbiting object, by expressing its velocity components in terms of the local circular speed. This relation is used to extend the results of our previous paper, examining the effects of an adhesive inelastic collision between a projectile launched from the surface of a planet (of radius R) and an equal-mass satellite in a circular orbit of radius r s. We show that there is a maximum orbital radius r s ≈ 18.9R beyond which such a collision cannot cause the satellite to impact the planet. The difficulty of bringing down a satellite in a high orbit with a surface-launched projectile provides a useful topic for a discussion of orbital angular momentum and energy. The material is suitable for an undergraduate intermediate mechanics course.
Marketing practices of vapor store owners.
Cheney, Marshall; Gowin, Mary; Wann, Taylor Franklin
2015-06-01
We examined the marketing strategies for local vapor stores in a large metropolitan area in Oklahoma. Vapor store owners or managers (n = 33) participated in individual interviews regarding marketing practices in 2014. We asked owners about their marketing strategies and the groups they targeted. We transcribed the interviews and analyzed them for themes. Store owners used a variety of marketing strategies to bring new customers to their stores and keep current customers coming back. These marketing strategies showed many parallels to tobacco industry strategies. Most owners engaged in some form of traditional marketing practices (e.g., print media), but only a few used radio or television advertising because of budget constraints. Owners used social media and other forms of electronic communication, pricing discounts and specials, and loyalty programs. Owners also had booths at local events, sponsored community events, and hosted them in their stores. Owners attempted to target different groups of users, such as college students and long-term smokers. Local vapor store marketing practices closely resemble current and former tobacco industry marketing strategies. Surveillance of marketing practices should include local and Web-based strategies.
Marketing Practices of Vapor Store Owners
Gowin, Mary; Wann, Taylor Franklin
2015-01-01
Objectives. We examined the marketing strategies for local vapor stores in a large metropolitan area in Oklahoma. Methods. Vapor store owners or managers (n = 33) participated in individual interviews regarding marketing practices in 2014. We asked owners about their marketing strategies and the groups they targeted. We transcribed the interviews and analyzed them for themes. Results. Store owners used a variety of marketing strategies to bring new customers to their stores and keep current customers coming back. These marketing strategies showed many parallels to tobacco industry strategies. Most owners engaged in some form of traditional marketing practices (e.g., print media), but only a few used radio or television advertising because of budget constraints. Owners used social media and other forms of electronic communication, pricing discounts and specials, and loyalty programs. Owners also had booths at local events, sponsored community events, and hosted them in their stores. Owners attempted to target different groups of users, such as college students and long-term smokers. Conclusions. Local vapor store marketing practices closely resemble current and former tobacco industry marketing strategies. Surveillance of marketing practices should include local and Web-based strategies. PMID:25880960
Yaqoob, Zahid; Arain, Muzammil A; Riza, Nabeel A
2003-09-10
A high-speed free-space wavelength-multiplexed optical scanner with high-speed wavelength selection coupled with narrowband volume Bragg gratings stored in photothermorefractive (PTR) glass is reported. The proposed scanner with no moving parts has a modular design with a wide angular scan range, accurate beam pointing, low scanner insertion loss, and two-dimensional beam scan capabilities. We present a complete analysis and design procedure for storing multiple tilted Bragg-grating structures in a single PTR glass volume (for normal incidence) in an optimal fashion. Because the scanner design is modular, many PTR glass volumes (each having multiple tilted Bragg-grating structures) can be stacked together, providing an efficient throughput with operations in both the visible and the infrared (IR) regions. A proof-of-concept experimental study is conducted with four Bragg gratings in independent PTR glass plates, and both visible and IR region scanner operations are demonstrated.
Wind-accelerated orbital evolution in binary systems with giant stars
Chen, Zhuo; Blackman, Eric G.; Nordhaus, Jason; Frank, Adam; Carroll-Nellenback, Jonathan
2018-01-01
Using 3D radiation-hydrodynamic simulations and analytic theory, we study the orbital evolution of asymptotic giant branch (AGB) binary systems for various initial orbital separations and mass ratios, and thus different initial accretion modes. The time evolution of binary separations and orbital periods are calculated directly from the averaged mass-loss rate, accretion rate and angular momentum loss rate. We separately consider spin-orbit synchronized and zero-spin AGB cases. We find that the angular momentum carried away by the mass loss together with the mass transfer can effectively shrink the orbit when accretion occurs via wind-Roche lobe overflow. In contrast, the larger fraction of mass lost in Bondi-Hoyle-Lyttleton accreting systems acts to enlarge the orbit. Synchronized binaries tend to experience stronger orbital period decay in close binaries. We also find that orbital period decay is faster when we account for the non-linear evolution of the accretion mode as the binary starts to tighten. This can increase the fraction of binaries that result in common envelope, luminous red novae, Type Ia supernovae and planetary nebulae with tight central binaries. The results also imply that planets in the habitable zone around white dwarfs are unlikely to be found.
Libration of arguments of circumbinary-planet orbits at resonance
Schubart, Joachim
2017-06-01
The paper refers to fictitious resonant orbits of planet type that surround both components of a binary system. In case of 16 studied examples a suitable choice of the starting values leads to a process of libration of special angular arguments and to an evolution with an at least temporary stay of the planet in the resonant orbit. The ratio of the periods of revolution of the binary and a planet is equal to 1:5. Eight orbits depend on the ratio 1:5 of the masses of the binary components, but two other ratios appear as well. The basis of this study is the planar, elliptic or circular restricted problem of three bodies, but remarks at the end of the text refer to a four-body problem.
Direct imaging of multiple planets orbiting the star HR 8799
Energy Technology Data Exchange (ETDEWEB)
Marois, C; Macintosh, B; Barman, T; Zuckerman, B; Song, I; Patience, J; Lafreniere, D; Doyon, R
2008-10-14
Direct imaging of exoplanetary systems is a powerful technique that can reveal Jupiter-like planets in wide orbits, can enable detailed characterization of planetary atmospheres, and is a key step towards imaging Earth-like planets. Imaging detections are challenging due to the combined effect of small angular separation and large luminosity contrast between a planet and its host star. High-contrast observations with the Keck and Gemini telescopes have revealed three planets orbiting the star HR 8799, with projected separations of 24, 38, and 68 astronomical units. Multi-epoch data show counter-clockwise orbital motion for all three imaged planets. The low luminosity of the companions and the estimated age of the system imply planetary masses between 5 and 13 times that of Jupiter. This system resembles a scaled-up version of the outer portion of our Solar System.
Caspi, Caitlin E; Lenk, Kathleen; Pelletier, Jennifer E; Barnes, Timothy L; Harnack, Lisa; Erickson, Darin J; Laska, Melissa N
2017-06-05
Purchases at small/non-traditional food stores tend to have poor nutritional quality, and have been associated with poor health outcomes, including increased obesity risk The purpose of this study was to examine whether customers who shop at small/non-traditional food stores with more health promoting features make healthier purchases. In a cross-sectional design, data collectors assessed store features in a sample of 99 small and non-traditional food stores not participating in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in Minneapolis/St. Paul, MN in 2014. Customer intercept interviews (n = 594) collected purchase data from a bag check and demographics from a survey. Store measures included fruit/vegetable and whole grain availability, an overall Healthy Food Supply Score (HFSS), healthy food advertisements and in-store placement, and shelf space of key items. Customer nutritional measures were analyzed using Nutrient Databases System for Research (NDSR), and included the purchase of ≥1 serving of fruits/vegetables; ≥1 serving of whole grains; and overall Healthy Eating Index-2010 (HEI-2010) score for foods/beverages purchased. Associations between store and customer measures were estimated in multilevel linear and logistic regression models, controlling for customer characteristics and store type. Few customers purchased fruits and vegetables (8%) or whole grains (8%). In fully adjusted models, purchase HEI-2010 scores were associated with fruit/vegetable shelf space (p = 0.002) and the ratio of shelf space devoted to healthy vs. less healthy items (p = 0.0002). Offering ≥14 varieties of fruit/vegetables was associated with produce purchases (OR 3.9, 95% CI 1.2-12.3), as was having produce visible from the store entrance (OR 2.3 95% CI 1.0 to 5.8), but whole grain availability measures were not associated with whole grain purchases. Strategies addressing both customer demand and the availability of healthy food
Directory of Open Access Journals (Sweden)
Shereen Aiyub
2013-01-01
Full Text Available We present a case of mature congenital orbital teratoma managed with lid-sparing exenteration and dermis fat graft. This is a case report on the management of congenital orbital teratoma. A full-term baby was born in Fiji with prolapsed right globe which was surrounded by a nonpulsatile, cystic mass. Clinical and imaging features were consistent with congenital orbital teratoma. Due to limited surgical expertise, the patient was transferred to Adelaide, Australia for further management. The patient underwent a lid-sparing exenteration with frozen section control of the apical margin. A dermis fat graft from the groin was placed beneath the lid skin to provide volume. Histopathology revealed mature tissues from each of the three germ cell layers which confirmed the diagnosis of mature teratoma. We describe the successful use of demis fat graft in socket reconstruction following lid-sparing exenteration for congenital orbital teratoma.
Lovin, J. K.; Spradley, L. W.
1979-01-01
Package consisting of three separate programs used to accurately predict temperature distribution of spacecraft in planetary orbit is invaluable tool for design and analysis of other structures that must function in complex thermal environment.
Directory of Open Access Journals (Sweden)
Pratik Y Gogri
2015-01-01
Full Text Available Orbital abscess generally occurs in older children but it can rarely affect infants and neonates too. We report a case of community acquired methicillin resistant staphylococcus aureus (CA-MRSA neonatal orbital abscess in a 12-day-old term female neonate with no significant past medical history or risk factor for developing the infection. The case highlights the importance of consideration of CA-MRSA as a causative agent of neonatal orbital cellulitis even in a neonate without any obvious predisposing condition. Prompt initiation of appropriate medical therapy against MRSA and surgical drainage of the abscess prevents life threatening complications of orbital cellulitis which more often tend to be fatal in neonates.
Orbital interactions in chemistry
Albright, Thomas A; Whangbo, Myung-Hwan
2013-01-01
Explains the underlying structure that unites all disciplines in chemistry Now in its second edition, this book explores organic, organometallic, inorganic, solid state, and materials chemistry, demonstrating how common molecular orbital situations arise throughout the whole chemical spectrum. The authors explore the relationships that enable readers to grasp the theory that underlies and connects traditional fields of study within chemistry, thereby providing a conceptual framework with which to think about chemical structure and reactivity problems. Orbital Interactions
Redd, Frank J.; Cantrell, James N.; McCurdy, Greg
1992-09-01
The establishment of lunar bases will not end the need for remote sensing of the lunar surface by orbiting platforms. Human and robotic surface exploration will necessarily be limited to some proximate distance from the support base. Near real-time, high-resolution, global characterization of the lunar surface by orbiting sensing systems will continue to be essential to the understanding of the Moon's geophysical structure and the location of exploitable minerals and deposits of raw materials. The Lunar Orbital Prospector (LOP) is an orbiting sensing platform capable of supporting a variety of modular sensing packages. Serviced by a lunar-based shuttle, the LOP will permit the exchange of instrument packages to meet evolving mission needs. The ability to recover, modify, and rotate sensing packages allows their reuse in varying combinations. Combining this flexibility with robust orbit modification capabilities and near real-time telemetry links provides considerable system responsiveness. Maintenance and modification of the LOP orbit are accomplished through use of an onboard propulsion system that burns lunar-supplied oxygen and aluminum. The relatively low performance of such a system is more than compensated for by the elimination of the need for Earth-supplied propellants. The LOP concept envisions a continuous expansion of capability through the incorporation of new instrument technologies and the addition of platforms.
Learning web development with Bootstrap and AngularJS
Radford, Stephen
2015-01-01
Whether you know a little about Bootstrap or AngularJS, or you're a complete beginner, this book will enhance your capabilities in both frameworks and you'll build a fully functional web app. A working knowledge of HTML, CSS, and JavaScript is required to fully get to grips with Bootstrap and AngularJS.
A kinematic model for calculating the magnitude of angular ...
African Journals Online (AJOL)
Here we have formulated a model for calculating the magnitude of angular momentum transfer in a steady-state accretion disk using only two parameters; the transport coefficient of vorticity,w and the rate of change of angular velocity with radial distance, dW/ dR . With this model, the mass accretion rate in an accretion disk ...
Cubature/ Unscented/ Sigma Point Kalman Filtering with Angular Measurement Models
2015-07-06
Cubature/ Unscented/ Sigma Point Kalman Filtering with Angular Measurement Models David Frederic Crouse Naval Research Laboratory 4555 Overlook Ave...measurement and process non- linearities, such as the cubature Kalman filter, can perform ex- tremely poorly in many applications involving angular... Kalman filtering is a realization of the best linear unbiased estimator (BLUE) that evaluates certain integrals for expected values using different forms
Angular Momentum Transport in Quasi-Keplerian Accretion Disks ...
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
The specific angular momentum (angular momentum per unit mass) carried by a parcel of gas ... have used the Einstein summation convention in equation (2). For the .... incorrect. 3.3 Correction proposed by HM. HM claim that this is because Frank et al. (1992) have used an incorrect expression for vrel (i.e., equation (10)).
Epidemiology Of Angular Deformities Of The Knee In Children In ...
African Journals Online (AJOL)
Background: Bony problems such as angular deformities and metabolic bone disease are of high frequency in Nigeria. Objective: The aim of this study was to define the pattern of presentation in children with angular deformities of the knee. Methodology: It was an 18-month prospective study involving children aged ...
Poisson algebra of quasilocal angular momentum and its asymptotic limit
Yoon, Jong Hyuk; Oh, Seung Hun
2018-01-01
We study the previously proposed quasilocal angular momentum of gravitational fields in the absence of isometries. The quasilocal angular momentum L(ξ) has the following attractive properties; (i) it follows from Einstein’s constraint equations, (ii) it satisfies the Poisson algebra \
Senior's lifestyle and their store choice
Directory of Open Access Journals (Sweden)
Lesakova Dagmar
2014-01-01
Full Text Available To attract and retain customers, an understanding of their motives and reasons for selecting particular food and grocery store is needed. This is of particular importance in the growing segment of seniors. The size of the senior's market demands a better understanding of the older consumer. The aim of our study is to identify psychographic characteristics of the elderly consumer, and to indicate the lifestyle groups and the relationship between these groups and retail store attributes. Differences in the motives for patronizing specific food stores are analyzed for lifestyle groups. We use the lifestyle as a segmentation variable in the diverse population of seniors for the reason, that the lifestyle of the elderly provides more valuable information than chronological age alone. This information can be used by retailers to improve marketing strategies in order to appeal to a target group of senior shoppers. Empirical research is based on a self-administrated questionnaire aimed on the identification of the lifestyle characteristics and retail store attributes of the consumers in 65+ age, used for the choice of food purchasing retail stores. Lifestyles characteristics were measured by the respondents activities, interests and opinions (AIO. The results of the research indicate that there are differences among the lifestyle groups with significant differences in attitudes towards quality of products or internal store environment. Our research demonstrates the value of psychographic information over age alone regarding the patronage factors in store selection. Our study is a part of the research project VEGA 1/0612/12 'Determinants of the size, structure and tendences in the individual consumption of seniors'.
Iron stores assessment in alcoholic liver disease.
Costa Matos, Luís; Batista, Paulo; Monteiro, Nuno; Ribeiro, João; Cipriano, Maria A; Henriques, Pedro; Girão, Fernando; Carvalho, Armando
2013-06-01
The relation between alcoholic liver disease (ALD) and iron overload is well known. Liver biopsy is the gold standard for assessing iron stores. MRI is also validated for liver iron concentration (LIC) assessment. We aimed to assess the effect of active drinking in liver iron stores and the practicability of measuring LIC by MRI in ALD patients. We measured LIC by MRI in 58 ALD patients. We divided patients into two groups - with and without active alcoholism - and we compared several variables between them. We evaluated MRI-LIC, liver iron stores grade, ferritin and necroinflammatory activity grade for significant correlations. Significant necroinflammation (40.0% vs. 4.3%), LIC (40.1 vs. 24.3 µmol/g), and ferritin (1259.7 vs. 568.7 pmol/L) were significantly higher in drinkers. LIC values had a strong association with iron stores grade (r s = 0.706). Ferritin correlated with LIC (r s = 0.615), iron stores grade (r s = 0.546), and necroinflammation (r s = 0.313). The odds ratio for elevated serum ferritin when actively drinking was 7.32. Active alcoholism is associated with increased ALD activity. It is also the key factor in iron overload. Scheuers' semiquantitative score with Perls' staining gives a fairly accurate picture of liver iron overload. Serum ferritin also shows a good correlation with LIC values and biopsy iron stores grade. As most patients present only with mild iron overload, serum ferritin measurement and semiquantitative evaluation of iron stores are adequate, considering MRI high cost. However, if MRI is required to evaluate liver structure, LIC assessment could be performed without added cost.
The TWA 3 Young Triple System: Orbits, Disks, Evolution
Energy Technology Data Exchange (ETDEWEB)
Kellogg, Kendra [Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7 (Canada); Prato, L.; Avilez, I.; Wasserman, L. H.; Levine, S. E.; Bosh, A. S. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Torres, Guillermo [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Schaefer, G. H. [The CHARA Array of Georgia State University, Mount Wilson Observatory, Mount Wilson, CA 91023 (United States); Ruíz-Rodríguez, D. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Bonanos, Alceste Z. [IAASARS, National Observatory of Athens, 15236 Penteli (Greece); Guenther, E. W. [Thüringer Landessternwarte Tautenburg, D-07778 Tautenburg (Germany); Neuhäuser, R. [Astrophysikalisches Institut und Universitäts-Sternwarte, FSU Jena, Schillergäßchen 2-3, D-07745 Jena (Germany); Morzinski, Katie M.; Close, Laird; Hinz, Phil; Males, Jared R. [Steward Observatory, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721 (United States); Bailey, Vanessa, E-mail: kkellogg@uwo.ca, E-mail: lprato@lowell.edu [Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics, Stanford University, Stanford, CA, 94305 (United States)
2017-08-01
We have characterized the spectroscopic orbit of the TWA 3A binary and provide preliminary families of probable solutions for the TWA 3A visual orbit, as well as for the wide TWA 3A–B orbit. TWA 3 is a hierarchical triple located at 34 pc in the ∼10 Myr old TW Hya association. The wide component separation is 1.″55; the close pair was first identified as a possible binary almost 20 years ago. We initially identified the 35-day period orbital solution using high-resolution infrared spectroscopy that angularly resolved the A and B components. We then refined the preliminary orbit by combining the infrared data with a reanalysis of our high-resolution optical spectroscopy. The orbital period from the combined spectroscopic solution is ∼35 days, the eccentricity is ∼0.63, and the mass ratio is ∼0.84; although this high mass ratio would suggest that optical spectroscopy alone should be sufficient to identify the orbital solution, the presence of the tertiary B component likely introduced confusion in the blended optical spectra. Using millimeter imaging from the literature, we also estimate the inclinations of the stellar orbital planes with respect to the TWA 3A circumbinary disk inclination and find that all three planes are likely misaligned by at least ∼30°. The TWA 3A spectroscopic binary components have spectral types of M4.0 and M4.5; TWA 3B is an M3. We speculate that the system formed as a triple, is bound, and that its properties were shaped by dynamical interactions between the inclined orbits and disk.
Food and beverage purchases in corner stores, gas-marts, pharmacies and dollar stores.
Caspi, Caitlin E; Lenk, Kathleen; Pelletier, Jennifer E; Barnes, Timothy L; Harnack, Lisa; Erickson, Darin J; Laska, Melissa N
2017-10-01
Little is known about customer purchases of foods and beverages from small and non-traditional food retailers (i.e. corner stores, gas-marts, dollar stores and pharmacies). The present study aimed to: (i) describe customer characteristics, shopping frequency and reasons for shopping at small and non-traditional food retailers; and (ii) describe food/beverage purchases and their nutritional quality, including differences across store type. Data were collected through customer intercept interviews. Nutritional quality of food/beverage purchases was analysed; a Healthy Eating Index-2010 (HEI-2010) score for purchases was created by aggregating participant purchases at each store. Small and non-traditional food stores that were not WIC-authorized in Minneapolis and St. Paul, MN, USA. Customers (n 661) from 105 food retailers. Among participants, 29 % shopped at the store at least once daily; an additional 44 % shopped there at least once weekly. Most participants (74 %) cited convenient location as the primary draw to the store. Customers purchased a median of 2262 kJ (540 kcal), which varied by store type (P=0·04). The amount of added sugar far surpassed national dietary recommendations. At dollar stores, participants purchased a median of 5302 kJ (1266 kcal) for a median value of $US 2·89. Sugar-sweetened beverages were the most common purchase. The mean HEI-2010 score across all stores was 36·4. Small and non-traditional food stores contribute to the urban food environment. Given the poor nutritional quality of purchases, findings support the need for interventions that address customer decision making in these stores.
Vrechopoulos, Adam P
2001-01-01
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. The research presented in this dissertation is concerned with the effects of the "virtual store atmosphere" on consumer buying behaviour within the context of Internet retailing. More specifically, the focus of this research is to investigate whether the virtual store layout, as a major virtual store atmosphere determinant, affects consumer buying behaviour during shopping activity w...
Doaa Khattab
2015-01-01
Many people with disabilities face considerable barriers while shopping in grocery stores. One such barrier is that they cannot find their way around easily, especially when they visit the grocery store for the first time and have not yet built a cognitive map in their memory. They may also experience delays in finding the right product or waiting for assistance from store employees, thus leading them to rely on family, friends, relatives, or volunteers to help them with their shopping. Prob...
CLASS: The Cosmology Large Angular Scale Surveyor
Essinger-Hileman, Thomas; Ali, Aamir; Amiri, Mandana; Appel, John W.; Araujo, Derek; Bennett, Charles L.; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T.;
2014-01-01
The Cosmology Large Angular Scale Surveyor (CLASS) is an experiment to measure the signature of a gravitational wave background from inflation in the polarization of the cosmic microwave background (CMB). CLASS is a multi-frequency array of four telescopes operating from a high-altitude site in the Atacama Desert in Chile. CLASS will survey 70% of the sky in four frequency bands centered at 38, 93, 148, and 217 GHz, which are chosen to straddle the Galactic-foreground minimum while avoiding strong atmospheric emission lines. This broad frequency coverage ensures that CLASS can distinguish Galactic emission from the CMB. The sky fraction of the CLASS survey will allow the full shape of the primordial B-mode power spectrum to be characterized, including the signal from reionization at low-length. Its unique combination of large sky coverage, control of systematic errors, and high sensitivity will allow CLASS to measure or place upper limits on the tensor-to-scalar ratio at a level of r = 0:01 and make a cosmic-variance-limited measurement of the optical depth to the surface of last scattering, tau. (c) (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Tracing the Angular Dependence of the CGM
Nattinger, Michael; Christensen, Charlotte
2017-01-01
The circumgalactic media (CGM) is enriched with metals through a process called the baryon cycle, which may play a significant role in the regulation of star formation. While the relationship between the CGM’s baryonic makeup and impact parameter is well documented, the relationship between the baryonic distribution of the CGM and the azimuthal angle out of the plane of the galaxy remains an open question. We investigated the angular distribution of baryons in the CGM by creating mock-absorption line spectra for a high-resolution simulation of a Milky Way-like galaxy at redshift zero. By comparison with data from the Cosmic Origins Spectrograph-Halos survey, we determined that our equivalent widths of HI, MgII, CIII, SiII, and SiIII are consistent with observations. Using our data, we found that low ionization state material is more prevalent at low azimuthal angles and that high ionization state material is more prevalent at high angles within the virial radius. We attributed this increased ionization to higher temperatures at high angles. We also found that the highest metallicity levels appear at high and low azimuthal angles, with lower metallicities at middle angles. This evidence supports the recycled accretion model of CGM baryon flow.
Miura, Takaho; Arakida, Hideyoshi; Kasai, Masumi; Kuramata, Shuichi
2009-12-01
We give an idea and order-of-magnitude estimations to explain a recently reported secular increase of the Astronomical Unit (AU) by Krasinsky and Brumberg (Krasinsky & Brumberg 2004, Celest. Mech. Dyn. Astron., 90, 267). The idea proposed is analogous to tidal acceleration in the Earth-Moon system, which is based on conservation of the total angular momentum; we apply this scenario to the Sun-planets system. Assuming the existence of some tidal interactions that transfer the rotational angular momentum of the Sun, and using a reported value of the positive secular trend in the Astronomical Unit, frac{d}{dt}AU = 15±4 (m cy-1), the suggested change in the period of rotation of the Sun is about 21 ms cy-1 in the case that the orbits of the eight planets have the same ``expansion rate.'' This value is sufficiently small, and at present it seems there are no observational data that exclude this possibility. The effects of a change in the Sun's moment of inertia is also investigated. It is pointed out that a change in the moment of inertia due to radiative mass loss by the Sun may be responsible for the secular increase of AU, if orbital ``expansion'' is happening only in the inner-planets system. Although the existence of some tidal interactions is assumed between the Sun and the planets, concrete mechanisms of angular-momentum transfer are not discussed in this paper, which remain to be pursued as future investigations.
O'Shaughnessy, R; London, L; Meeks, Z; Shoemaker, D
2012-01-01
The gravitational wave signature emitted from a merging binary depends on the orientation of an observer relative to the binary. Previous studies suggest that emission along the total initial or total final angular momenta leads to both the strongest and simplest signal from a precessing compact binary. In this paper we describe a concrete counterexample: a binary with $m_1/m_2=4$, $a_1=0.6 \\hat{x} = -a_2$, placed in orbit in the x,y plane. We extract the gravitational wave emission along several proposed emission directions, including the initial (Newtonian) orbital angular momentum; the final (~ initial) total angular momentum; and the dominant principal axis of $_M$. Using several diagnostics, we show that the suggested preferred directions are not representative. For example, only for a handful of other directions (0.95). We conclude that the information available in just one direction (or mode) does not adequately encode the complexity of orientation-dependent emission for even short signals from merging...
[Orbital complications of sinusitis].
Šuchaň, M; Horňák, M; Kaliarik, L; Krempaská, S; Koštialová, T; Kovaľ, J
2014-12-01
Orbital complications categorised by Chandler are emergency. They need early diagnosis and agresive treatment. Stage and origin of orbital complications are identified by rhinoendoscopy, ophtalmologic examination and CT of orbite and paranasal sinuses. Periorbital cellulitis and early stage of orbital cellulitis can be treated conservatively with i. v. antibiotics. Monitoring of laboratory parameters and ophtalmologic symptoms is mandatory. Lack of improvement or worsening of symptoms within 24-48 hours and advanced stages of orbital complications are indicated for surgery. The purpose of the study is to evaluate epidemiology, clinical features and management of sinogenic orbital complications. Retrospective data of 8 patients with suspicion of orbital complication admited to hospital from 2008 to 2013 were evaluated. Patients were analyzed in terms of gender, age, CT findings, microbiology, clinical features, stage and treatment. Male and female were afected in rate 1,66:1. Most of patients were young adult in 3rd. and 4th. decade of life (62,5 %). Acute and chronic sinusitis were cause of orbital complication in the same rate. The most common origin of orbital complication was ethmoiditis (62,5 %), than maxillary (25 %) and frontal (12,5 %) sinusitis. Polysinusitis with affection of ethmoidal, maxillary and frontal sinuses (75 %) was usual CT finding. Staphylococcus epidermidis and Staphylococcus aureus were etiological agens in half of cases. Periorbital oedema (100 %), proptosis, chemosis (50 %), diplopia and glaucoma (12,5 %) were observed. Based on examinations, diagnosis of periorbital oedema/preseptal cellulitis was made in 3 (37,5 %), orbital cellulitis in 3 (37,5 %) and subperiosteal abscess in 2 cases (25 %). All patients underwent combined therapy - i. v. antibiotics and surgery within 24 hours. Eradication of disease from ostiomeatal complex (OMC), drainage of affected sinuses and drainage of subperiosteal abscess were done via fuctional endonasal
Orbital complications of rhinosinusitis.
Sijuwola, Oo; Adeyemo, Aa; Adeosun, Aa
2007-06-01
Suppurative extension of rhinosinusitis to the orbit is a complication that often results from delay in diagnosis and, or inadequate treatment. These complications may range from preseptal cellulitis, orbital cellulitis, orbital abscesses, and subperiosteal abscesses to intracranial extension with a threat to both vision and life. This study aims to review the clinical profile, treatment modalities and outcome of orbital complications of rhinosinusitis in Ibadan, Nigeria. A retrospective review of the charts of patients with orbital complications of rhinosinusitis managed in the departments of Otorhinolaryngology and Ophthalmology, University College Hospital, Ibadan over a five year period (Feb 2002- Jan 2007) was carried out .The diagnosis of rhinosinusitis was based on history, physical examination, plain x ray and CT scan findings and antral puncture. Demographic data, clinical presentation and treatment were evaluated. A total of 24 patients were reviewed in the study. There were 13males and 11females (M/F, 1:1). The age range was 8months to 75years, 14 (58.3%) patients were children and while 10 (41.7%) patients were adults. 75% of the patients were seen during the dry season (November to February). The duration of symptoms ranged from one day to three weeks. Involvement of one eye occurred in 14 patients (58.3%); right eye (4), left eye (10). Both eyes were involved in 10 patients (41.7%). Non-axial proptosis was seen in 8 patients (33.3%). It was infero-lateral in 6 patients (25%) and infero-nasal in two (8.3%) patients. Orbital cellulitis was seen in 10 (41.7%) patients, 6 (25%) patients had preseptal cellulitis while 8 (33%) patients had orbital abscess. Cavernous sinus thrombosis was seen in 3 (12.5%) patients. The cases with preseptal and orbital cellulitis were effectively managed by intravenous antibiotics. Orbital abscesses were drained surgically with complete resolution. Sinus surgical procedures were done in 10(41.7%) patients. This group of
Banović, Marija; Grunert, Klaus G; Barreira, Maria Madalena; Fontes, Magda Aguiar
2010-01-01
This study investigated the differences in the consumers' quality perception of national branded, national store branded, and imported store branded beef. Partial Least Squares analysis is used for modelling the quality perception process. Results show that consumers perceived national branded Carnalentejana beef, as better on all quality cues and quality aspects than the other two store branded beefs. Preference for Carnalentejana beef stayed highly consistent even after the blind test, where consumers differentiated this beef from the other two beef brands on all sensory dimensions: taste, tenderness, and juiciness, and chose it as the preferred one. Consumers utilized more perceived intrinsic cues to infer expected eating quality of store branded beefs.
Peranan Store Atmosphere Dalam Meningkatkan Keputusan Pembelian
Directory of Open Access Journals (Sweden)
Rennyta Yusiana
2017-04-01
ABSTRACT Bandung is a destination for domestic and foreign tourists with culinary goals. There are many restaurants and cafes offering a variety of culinary tastes, ranging from culinary archipelago to abroad. Nowadays consumers are attracted to the restaurant and cafe with a different atmosphere. One of them is the Hummingbird Eatery which implementing store homey atmosphere, with the cozy interior and dominated by furniture made of wood. Atmosphere is an important factor for consumers in choosing where to dine and relax. Cozy atmosphere with unique decor and creative appeal to a restaurant that makes consumers visit. This study aims to determine consumer response regarding the role of Store Atmosphere in increasing consumer purchasing decisions. This type of research is descriptive and quantitative, using 100 samples. Data collection techniques used were questionnaires, observations, interviews, and literature studies. This study uses SPSS V.22 and simple linear regression. The results of this study indicate that the general interior becomes a major consideration as a benefit for consumers in making purchasing decisions apart from other sub variables store atmosphere. Managers can prioritize managing general interior more effectively, because consumers prefer it in the store atmosphere. Keywords: Store Atmosphere, Purchase Decision
How do External Companions Affect Spin-Orbit Misalignment of Hot Jupiters?
Lai, Dong; Anderson, Kassandra R.; Pu, Bonan
2018-01-01
Consider a planet with its orbital angular momentum axis aligned with the spin axis of its host star. To what extent does an inclined distant companion (giant planet or binary star) affect this alignment? We provide an analytic, quantitative answer and apply it to hot Jupiter systems, for which misalignments between the orbital axis and the stellar spin axis have been detected. We also show how similar consideration can be applied to multi-planet systems with distant companions (such as Kepler-56). The result of this paper provides a simple method to assess the dynamical role played by external companions on spin-orbit misalignments in exoplanetary systems.
Orbital Support of Fast and Slow Inner Bars in Double Barred Galaxies
Maciejewski, Witold; Small, Emma E.
2010-01-01
We analyze how the orbital support of the inner bar in a double-barred galaxy (nested bars) depends on the angular velocity (i.e. pattern speed) of this bar. We study orbits in seven models of double bars using the method of invariant loops. The range of pattern speed is covered exhaustively. We find that not all pattern speeds are allowed when the inner bar rotates in the same direction as the outer bar. Below a certain minimum pattern speed orbital support for the inner bar abruptly disappe...
Sauvan, Patrick; Koning, Arjan; Ogando, Francisco; Sanz, Javier
2017-09-01
MCUNED code is an MCNPX extension able to handle evaluated nuclear data library for light ion transport simulations. In this work the MCUNED code is improved to describe more accurately the neutron emission during deuteron induced nuclear reaction. This code update consists in introducing a new methodology to take into account the angular distribution of neutron produced by deuteron breakup reaction. To carry out this work a new formulation for the angular distribution of neutrons produced by breakup reaction has been proposed. The implementation of this new methodology requires the use of extra parameters which are provided by the nuclear code TALYS and stored in the ENDF file. This new methodology shows significant improvement in comparison with the former treatment of neutron emission kinematics, these results are in good agreement with experimental data.
Entrance Effects in Solar Hot Water Stores
DEFF Research Database (Denmark)
Shah, Louise Jivan; Furbo, Simon
2003-01-01
A theoretical and experimental analysis of water jets entering a solar storage tank is performed. CFD calculations of three inlet designs with different inlet flow rates were carried out to illustrate the varying behaviour of the thermal conditions in a solar store. The results showed the impact...... of the inlet design on the flow patterns in the tank and thus how the energy quality in a hot water tank is reduced with a poor inlet design. The numerical investigations were followed by experiments. A test solar store, similar to the store investigated by numerical modelling was constructed with cylindrical...... transparent walls so that the flow structures due to the inlet jets could be visualized. With the three inlets, nine draw-off tests with different inlet flow rates were carried out and the temperature stratification in the tank was measured during the draw-offs. The experimental results were used...
Understanding Consumers' In-store Visual Perception
DEFF Research Database (Denmark)
Clement, Jesper; Kristensen, Tore; Grønhaug, Kjell
2013-01-01
It is widely accepted that the human brain has limited capacity for perceptual stimuli and consumers'' visual attention, when searching for a particular product or brand in a grocery store, should then be limited by the boundaries of their own perceptual capacity. In this exploratory study, we...... examine the relationship between abundant in-store stimuli and limited human perceptual capacity. Specifically, we test the influence of package design features on visual attention. Data was collected through two eye-tracking experiments, one in a grocery store using wireless eye-tracking equipment......, and another in a lab setting. Findings show that consumers have fragmented visual attention during grocery shopping, and that their visual attention is simultaneously influenced and disrupted by the shelf display. Physical design features such as shape and contrast dominate the initial phase of searching...
Calculation of photoionization differential cross sections using complex Gauss-type orbitals.
Matsuzaki, Rei; Yabushita, Satoshi
2017-09-05
Accurate theoretical calculation of photoelectron angular distributions for general molecules is becoming an important tool to image various chemical reactions in real time. We show in this article that not only photoionization total cross sections but also photoelectron angular distributions can be accurately calculated using complex Gauss-type orbital (cGTO) basis functions. Our method can be easily combined with existing quantum chemistry techniques including electron correlation effects, and applied to various molecules. The so-called two-potential formula is applied to represent the transition dipole moment from an initial bound state to a final continuum state in the molecular coordinate frame. The two required continuum functions, the zeroth-order final continuum state and the first-order wave function induced by the photon field, have been variationally obtained using the complex basis function method with a mixture of appropriate cGTOs and conventional real Gauss-type orbitals (GTOs) to represent the continuum orbitals as well as the remaining bound orbitals. The complex orbital exponents of the cGTOs are optimized by fitting to the outgoing Coulomb functions. The efficiency of the current method is demonstrated through the calculations of the asymmetry parameters and molecular-frame photoelectron angular distributions of H2+ and H2 . In the calculations of H2 , the static exchange and random phase approximations are employed, and the dependence of the results on the basis functions is discussed. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
Chua, D. H.; Korendyke, C.; Vourlidas, A.; Moses, J.; Brown, C.
2013-12-01
The Naval Research Laboratory (NRL) Space Science Division (SSD) sounding rocket program enables cutting-edge scientific research through the development of low-cost, short-schedule, highly advanced suborbital payloads. Each sounding rocket campaign provides a low-cost and accordingly low-risk test bed for the technology development of future flight projects. Our approach is to maintain a continuous hardware development program through a successful cycle of concept inception, competition in the NASA LCAS (Low-Cost Access to Space) program, instrument development, launch, and science analysis. Currently, SSD has three active sounding rocket programs. HERSCHEL (HElium Resonance Scattering in the Corona & HELio-sphere) was successfully flown in 2010 and measured the global helium absolute abundance in the solar corona for the first time, linking solar surface and in-situ abundance. The HERSCHEL experiment served as the pathfinder for the METIS coronagraph that will fly on Solar Orbiter. VERIS (VEry high Resolution Imaging Spectrometer) is scheduled for launch in August 2013 and will provide the first spectroscopic observations of the solar atmosphere at spatial scales not yet observed by previous EUV spectrographs. VERIS is the test bed for a flight hardware concept to be proposed to NASA for the upcoming JAXA Solar-C mission. VAULT (Very high Angular resolution Ultraviolet Telescope), scheduled for re-flight in Fall 2013, will provide ultra high-resolution images of the Lyman-alpha layer of the upper chromosphere where much of the energy required for explosive events is stored. Previous VAULT sounding rocket flights provided the first sub-arcsecond solar images from space and led to the development of a Lyman-alpha telescope for the Solar Orbiter mission. Through these next sounding rocket flights NRL SSD will provide scientific leadership in the budding field of upper chromospheric research.
An exploratory study of the relationship between store image, trust ...
African Journals Online (AJOL)
owned stores, consumers have an overall better perception of franchise stores, especially in terms of trust and customer satisfaction. Examining an integrative loyalty framework, the study shows diff erential eff ects in how Store Image elements infl ...
COLLABORATION BETWEEN SMALL RETAIL STORES AND SUPPLIERS OF FOOD PRODUCTS
National Research Council Canada - National Science Library
Lenka Branska; Michal Paták; Zuzana Pecinová
2017-01-01
... on store location and the possible affiliation of the store with a retail chain. To achieve this goal, quantitative research was carried out among 65 Czech retail stores using face-to-face interviews with predetermined questions...
Spin Orbit Torque in Ferromagnetic Semiconductors
Li, Hang
2016-06-21
Electrons not only have charges but also have spin. By utilizing the electron spin, the energy consumption of electronic devices can be reduced, their size can be scaled down and the efficiency of `read\\' and `write\\' in memory devices can be significantly improved. Hence, the manipulation of electron spin in electronic devices becomes more and more appealing for the advancement of microelectronics. In spin-based devices, the manipulation of ferromagnetic order parameter using electrical currents is a very useful means for current-driven operation. Nowadays, most of magnetic memory devices are based on the so-called spin transfer torque, which stems from the spin angular momentum transfer between a spin-polarized current and the magnetic order parameter. Recently, a novel spin torque effect, exploiting spin-orbit coupling in non-centrosymmetric magnets, has attracted a massive amount of attention. This thesis addresses the nature of spin-orbit coupled transport and torques in non-centrosymmetric magnetic semiconductors. We start with the theoretical study of spin orbit torque in three dimensional ferromagnetic GaMnAs. Using the Kubo formula, we calculate both the current-driven field-like torque and anti-damping-like torque. We compare the numerical results with the analytical expressions in the model case of a magnetic Rashba two-dimensional electron gas. Parametric dependencies of the different torque components and similarities to the analytical results of the Rashba two-dimensional electron gas in the weak disorder limit are described. Subsequently we study spin-orbit torques in two dimensional hexagonal crystals such as graphene, silicene, germanene and stanene. In the presence of staggered potential and exchange field, the valley degeneracy can be lifted and we obtain a valley-dependent Berry curvature, leading to a tunable antidamping torque by controlling the valley degree of freedom. This thesis then addresses the influence of the quantum spin Hall
King-Hele, D. G.
2005-07-01
Satellites as they cross the night sky look like moving stars, which can be accurately tracked by an observer with binoculars as well as by giant radars and large cameras. These observations help to determine the satellite's orbit, which is sensitive to the drag of the upper atmosphere and to any irregularities in the gravity field of the Earth. Analysis of the orbit can be used to evaluate the density of the upper atmosphere and to define the shape of the Earth. Desmond King-Hele was the pioneer of this technique of orbit analysis, and this book tells us how the research began, before the launch of Sputnik in 1957. For thirty years King-Hele and his colleagues at the Royal Aircraft Establishment, Farnborough, developed and applied the technique to reveal much about the Earth and air at a very modest cost. In the 1960s the upper-atmosphere density was thoroughly mapped out for 100 to 2000 km, revealing immense variation of density with solar activity and between day and night. In the 1970s and 1980s a picture of the upper-atmosphere winds emerged, and the profile of the pear-shaped Earth was accurately charted. The number of satellites now orbiting the earth is over 5000. This book is the story of how this inexpensive research of their orbits developed to yield a rich harvest of knowledge about the Earth and its atmosphere, in a scientific narrative that is enlivened with many personal experiences.
Extended duration orbiter (EDO) insignia
1990-01-01
Extended duration orbiter (EDO) insignia incorporates a space shuttle orbiter with payload bay doors (PLBDs) open and a spacelab module inside. Trailing the orbiter are the initials EDO. The EDO-modified Columbia, Orbiter Vehicle (OV) 102, will be flown for the first EDO mission, STS-50.
Relative motion of orbiting bodies
Butikov, Eugene I.
2001-01-01
A problem of relative motion of orbiting bodies is investigated on the example of the free motion of any body ejected from the orbital station that stays in a circular orbit around the earth. An elementary approach is illustrated by a simulation computer program and supported by a mathematical treatment based on approximate differential equations of the relative orbital motion.
Elliptical Orbit Performance Computer Program
Myler, T.
1984-01-01
Elliptical Orbit Performance (ELOPE) computer program for analyzing orbital performance of space boosters uses orbit insertion data obtained from trajectory simulation to generate parametric data on apogee and perigee altitudes as function of payload data. Data used to generate presentation plots that display elliptical orbit performance capability of space booster.
Interferometric measurement of the angular velocity of moving humans
Nanzer, Jeffrey A.
2012-06-01
This paper presents an analysis of the measurement of the angular velocity of walking humans using a millimeter-wave correlation interferometer. Measurement of the angular velocity of moving objects is a desirable function in remote sensing applications. Doppler radar sensors are able to measure the signature of moving humans based on micro-Doppler analysis; however, a person moving with little to no radial velocity produces negligible Doppler returns. Measurement of the angular movement of humans can be done with traditional radar techniques, however the process involves either continuous tracking with narrow beamwidth or angle-of-arrival estimation algorithms. A new method of measuring the angular velocity of moving objects using interferometry has recently been developed which measures the angular velocity of an object without tracking or complex processing. The frequency of the interferometer signal response is proportional to the angular velocity of the object as it passes through the interferometer beam pattern. In this paper, the theory of the interferometric measurement of angular velocity is covered and simulations of the response of a walking human are presented. Simulations are produced using a model of a walking human to show the significant features associated with the interferometer response, which may be used in classification algorithms.
DEFF Research Database (Denmark)
Banovic, Marija; Grunert, Klaus G.; Barreira, Maria Madalena
2010-01-01
This study investigated the differences in the consumers' quality perception of national branded, national store branded, and imported store branded beef. Partial Least Squares analysis is used for modelling the quality perception process. Results show that consumers perceived national branded Ca...
Influence of Retail Store Design on the Performance of Retail Store Managers
Directory of Open Access Journals (Sweden)
Irina Olimpia SUSANU
2011-11-01
Full Text Available The purpose of this study is to examine the influence of retail store design on the performance and job satisfaction of retail store managers. A structural equations model is tested with 200 managers of a large supermarket chain. Moderating effects of crowding and perceived control on design satisfaction are examined. Managerial implications for strategy and theoretical contributions are discussed.
Gijsbrechts, E.; Campo, K.; Nisol, P.
2005-01-01
In this paper, we demonstrate that single-purpose multiple store shopping is not only driven by opportunistic, promotion-based motivations, but may also be part of a longer term shopping planning process based on stable store characteristics.Starting from a utility-maximizing shopping behavior
Basanta, I; Sevillano, C; Álvarez, M D
2015-09-01
A case is presented of an 85 year-old Caucasian female with lymphoma that recurred in the orbit (secondary ocular adnexal lymphoma). The orbital tumour was a diffuse large B-cell lymphoma according to the REAL classification (Revised European-American Lymphoma Classification). Orbital lymphomas are predominantly B-cell proliferations of a variety of histological types, and most are low-grade tumours. Patients are usually middle-aged or elderly, and it is slightly more common in women. A palpable mass, proptosis and blepharoptosis are the most common signs of presentation. Copyright © 2011 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.
The influence of store image on customer satisfaction: a case study of a shoe store
Directory of Open Access Journals (Sweden)
Tarsis Souza Silva
2010-01-01
Full Text Available Knowledge of customers' image of a store is an essential factor in the management of retail outlets. This article presents a case study of the effect of the image customers have of a shoe store on their satisfaction, based on a descriptive and quantitative survey, with the application of a structured questionnaire. We then employed factor analysis to obtain seven store image factors: assortment, convenience, reputation, price, atmosphere, layout and service. The results show that the factor that most affects customer satisfaction in the store studied is service, and that atmosphere and layout have no effect in this respect. The results provide a better understanding of the role store image plays in customer satisfaction and loyalty.
Preseptal Cellulitis Or Orbital Cellulitis?
Lim, L T; Miller, D; Ah-Kee, E Y; Ferguson, A
2015-06-29
Preseptal cellulitis and orbital cellulitis can both present with increasing swelling, tenderness and redness around the eye, but their management differs. Preseptal cellulitis is more common and much less aggressive than orbital cellulitis. In contrast, orbital cellulitis is a medical emergency requiring urgent management. In this article, we provide a systematic approach to distinguish between preseptal cellulitis and orbital cellulitis at presentation, as the distinction between the two entities and the prompt recognition of orbital cellulitis can be potentially life-saving.
Preliminary orbit determination
Taff, L. G.; Belkin, B.; Schweiter, G.; Sommar, K.
The problem of intercontinental ballistic missile reentry vehicle orbit determination from incomplete passive (i.e., angles-only) or active (i.e., distance plus angles) information is presented. Launch location and time and impact location and time to complete the computation of an orbital element set are utilized. In addition, it is possible to construct a good estimate of the variance of the key quantity in the angles only case; namely the computed topocentric distance. This type of observation/information situation is enlarged to include a complete discussion of single-point differential correction.
Oppenheimer, Adam J.; Monson, Laura A.; Buchman, Steven R.
2013-01-01
It is wise to recall the dictum “children are not small adults” when managing pediatric orbital fractures. In a child, the craniofacial skeleton undergoes significant changes in size, shape, and proportion as it grows into maturity. Accordingly, the craniomaxillofacial surgeon must select an appropriate treatment strategy that considers both the nature of the injury and the child's stage of growth. The following review will discuss the management of pediatric orbital fractures, with an emphasis on clinically oriented anatomy and development. PMID:24436730
[Orbital complications of rhinosinusitis].
Stojanović, J; Ilić, N; Belić, B; Zivić, L; Stanković, P; Erdevicki, L; Jovanović, S
2009-01-01
Orbital complications were observed in 53 patients (1.35%, n=53/3912 of all treated patients; 11.04%, n= 53/480 of hospitalized patients). Complications in the orbit can occur in 3-5% of adults with the inflammatory condition of sinuses, while the percentage in children ranges from 0.5-8%. The objective of our work was to determine the frequency of the occurence of orbital complications of the rhinosinal inflammatory origin in a group of adults and children. The retrospective analysis of patients treated of rhinosinusitis in the period 1992 to 2007, in the Clinical Center in Kragujevac. In the period of 15 years, a total number of 3912 patients were treated for inflamatory conditions of paranasal cavities. Orbital complications were found in 53 patients (1.35%, n=53/3912 of all treated patients). The number of children showing orbital complications caused by rhinosinusitis was 0.79%, while the number of adults was 1,88%. Acute rhinosinusitis in children was manifested as orbital complication in 14 patients (n=14/15, 93.33%), while 33 adults (n=33/38, 86.84%) had the exarcerbation of the chronic rhinosinusitis at the time of diagnosis of orbital complication. 80% of examined children had the maxillary and ethmoid sinus infected (n=12/15), while the adults most often had polysinusitis (n=22/38, 57.89%). In the juvenile age the most frequent complication was the cellulitis of the orbite (n=7/15, 46.66%), while in the adults it was the subperiostal absces (n=14/38, 36.84%). The adults were mostly treated surgically (n=31/38, 81.58%), while the children were treated by using conservative treatment (n=13/15, 86.67%). There were no cases of mortality. The prevention of complications is based on the adequate and timely treatment of acute sinusitis in children, as well as the curative treatment of chronical processes in adults.
Friedman, Morton l.; Garrett, James, Major
An analog aid to determine satellite coverage of Emergency Locator Transmitters Emergency Position Indicating Radio Beacon (ELT/EPIRB) distress incidence is discussed. The satellite orbit predictor is a graphical aid for determining the relationship between the satellite orbit, antenna coverage of the spacecraft and coverage of the Local User Terminal. The predictor allows the user to quickly visualize if a selected position will probably be detected and is composed of a base map and a satellite track overlay for each satellite.A table of equator crossings for each satellite is included.
Energy Technology Data Exchange (ETDEWEB)
Khuseynov, Dmitry; Blackstone, Christopher C.; Culberson, Lori M.; Sanov, Andrei, E-mail: sanov@u.arizona.edu [Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721 (United States)
2014-09-28
We present a model for laboratory-frame photoelectron angular distributions in direct photodetachment from (in principle) any molecular orbital using linearly polarized light. A transparent mathematical approach is used to generalize the Cooper-Zare central-potential model to anionic states of any mixed character. In the limit of atomic-anion photodetachment, the model reproduces the Cooper-Zare formula. In the case of an initial orbital described as a superposition of s and p-type functions, the model yields the previously obtained s-p mixing formula. The formalism is further advanced using the Hanstorp approximation, whereas the relative scaling of the partial-wave cross-sections is assumed to follow the Wigner threshold law. The resulting model describes the energy dependence of photoelectron anisotropy for any atomic, molecular, or cluster anions, usually without requiring a direct calculation of the transition dipole matrix elements. As a benchmark case, we apply the p-d variant of the model to the experimental results for NO{sup −} photodetachment and show that the observed anisotropy trend is described well using physically meaningful values of the model parameters. Overall, the presented formalism delivers insight into the photodetachment process and affords a new quantitative strategy for analyzing the photoelectron angular distributions and characterizing mixed-character molecular orbitals using photoelectron imaging spectroscopy of negative ions.
On Angular Sampling Methods for 3-D Spatial Channel Models
DEFF Research Database (Denmark)
Fan, Wei; Jämsä, Tommi; Nielsen, Jesper Ødum
2015-01-01
This paper discusses generating three dimensional (3D) spatial channel models with emphasis on the angular sampling methods. Three angular sampling methods, i.e. modified uniform power sampling, modified uniform angular sampling, and random pairing methods are proposed and investigated in detail....... The random pairing method, which uses only twenty sinusoids in the ray-based model for generating the channels, presents good results if the spatial channel cluster is with a small elevation angle spread. For spatial clusters with large elevation angle spreads, however, the random pairing method would fail...
Control of Angular Intervals for Angle-Multiplexed Holographic Memory
Kinoshita, Nobuhiro; Muroi, Tetsuhiko; Ishii, Norihiko; Kamijo, Koji; Shimidzu, Naoki
2009-03-01
In angle-multiplexed holographic memory, the full width at half maximum of the Bragg selectivity curves is dependent on the angle formed between the medium and incident laser beams. This indicates the possibility of high density and high multiplexing number by varying the angular intervals between adjacent holograms. We propose an angular interval scheduling for closely stacking holograms into medium even when the angle range is limited. We obtained bit error rates of the order of 10-4 under the following conditions: medium thickness of 1 mm, laser beam wavelength of 532 nm, and angular multiplexing number of 300.
Notes on the quantum theory of angular momentum
Feenberg, Eugene
1999-01-01
This classic, concise text has served a generation of physicists as an exceptionally useful guide to the mysteries of angular momenta and Clebsch-Gordon Coefficients. Derived from notes originally prepared to assist graduate students in reading research papers on atomic, molecular, and nuclear structure, the text first reviews the basic elements of quantum theory. It then examines the development of the fundamental commutation relations for angular momentum components and vector operators, and the ways in which matrix elements and eigenvalues of the angular momentum operators are worked out f
Angular resolution of air-shower array-telescopes
Linsley, J.
1985-01-01
A fundamental limit on the angular resolution of air shower array-telescopes is set by the finite number of shower particles coupled with the finite thickness of the particle swarm. Consequently the angular resolution which can be achieved in practice depends in a determinant manner on the size and number of detectors in an array-telescope, as well as on the detector separation and the timing resolution. It is also necessary to examine the meaning of particle density in whatever type of detector is used. Results are given which can be used to predict the angular resolution of a given instrument for showers of various sizes, and to compare different instruments.