Kerr nonlinear coupler and entanglement
International Nuclear Information System (INIS)
Leonski, Wieslaw; Miranowicz, Adam
2004-01-01
We discuss a model comprising two coupled nonlinear oscillators (Kerr-like nonlinear coupler) with one of them pumped by an external coherent excitation. Applying the method of nonlinear quantum scissors we show that the quantum evolution of the coupler can be closed within a finite set of n-photon Fock states. Moreover, we show that the system is able to generate Bell-like states and, as a consequence, the coupler discussed behaves as a two-qubit system. We also analyse the effects of dissipation on entanglement of formation parametrized by concurrence
Modulational instability in nonlocal nonlinear Kerr media
DEFF Research Database (Denmark)
Krolikowski, Wieslaw; Bang, Ole; Juul Rasmussen, Jens
2001-01-01
We study modulational instability (MI) of plane waves in nonlocal nonlinear Kerr media. For a focusing nonlinearity we show that, although the nonlocality tends to suppress MI, it can never remove it completely, irrespective of the particular profile of the nonlocal response function. For a defoc...
Optical activity via Kerr nonlinearity in a spinning chiral medium
Energy Technology Data Exchange (ETDEWEB)
Khan, Anwar Ali, E-mail: anwarali@uom.edu.pk [Department of Physics, University of Malakand at Chakdara Dir(L) (Pakistan); Bacha, Bakht Amin, E-mail: aminoptics@gmail.com [Department of Physics, University of Malakand at Chakdara Dir(L) (Pakistan); Khan, Rahmat Ali, E-mail: rahmat_alipk@yahoo.com [Department of Mathematics, University of Malakand (Pakistan)
2016-11-11
Optical activity is investigated in a chiral medium by employing the four level cascade atomic model, in which the optical responses of the atomic medium are studied with Kerr nonlinearity. Light entering into a chiral medium splits into circular birefringent beams. The angle of divergence between the circular birefringent beams and the polarization states of the two light beams is manipulated with Kerr nonlinearity. In the stationary chiral medium the angle of divergence between the circular birefringent beams is calculated to be 1.3 radian. Furthermore, circular birefringence is optically controlled in a spinning chiral medium, where the maximum rotary photon drag angle for left (right) circularly polarized beam is ±1.1 (±1.5) microradian. The change in the angle of divergence between circular birefringent beams by rotary photon drag is calculated to be 0.4 microradian. The numerical results may help to understand image designing, image coding, discovery of photonic crystals and optical sensing technology. - Highlights: • Coherent control of a circular birefringence in a chiral medium is studied. • Angle of divergence between birefringent beams is modified with Kerr nonlinearity. • Rotary photon drag is controlled for birefringent beams and enhanced with Kerr nonlinearity in a spinning medium. • Rotation of the angle of divergence is observed with mechanical rotation of the medium about an axis and modified with Kerr effect. • A change in the angle of divergence is calculated by about a microradian with rotary photon drag.
Cross-Kerr nonlinearities in an optically dressed periodic medium
Energy Technology Data Exchange (ETDEWEB)
Slowik, K; Raczynski, A; Zaremba, J [Instytut Fizyki, Uniwersytet Mikolaja Kopernika, ulica Grudziadzka 5, 87-100 Torun (Poland); Zielinska-Kaniasty, S [Instytut Matematyki i Fizyki, Uniwersytet Technologiczno-Przyrodniczy, Aleja Prof. S Kaliskiego 7, 85-789 Bydgoszcz (Poland); Artoni, M [Department of Physics and Chemistry of Materials, CNR-INFM Sensor Lab, Brescia University and European Laboratory for Nonlinear Spectroscopy, Firenze (Italy); La Rocca, G C, E-mail: karolina@fizyka.umk.pl [Scuola Normale Superiore and CNISM, Pisa (Italy)
2011-02-15
Cross-Kerr nonlinearities are analyzed for two light beams propagating in an atomic medium in the tripod configuration, dressed by a strong standing-wave laser field that induces periodic optical properties. The reflection and transmission spectra as well as the phases of both the reflected and transmitted components of the two beams are analyzed theoretically with nonlinearities up to third order being taken into account. Ranges of parameters are sought in which the cross-Kerr effect can be used as the basis of the phase gate.
Non-linear Q-clouds around Kerr black holes
Directory of Open Access Journals (Sweden)
Carlos Herdeiro
2014-12-01
Full Text Available Q-balls are regular extended ‘objects’ that exist for some non-gravitating, self-interacting, scalar field theories with a global, continuous, internal symmetry, on Minkowski spacetime. Here, analogous objects are also shown to exist around rotating (Kerr black holes, as non-linear bound states of a test scalar field. We dub such configurations Q-clouds. We focus on a complex massive scalar field with quartic plus hexic self-interactions. Without the self-interactions, linear clouds have been shown to exist, in synchronous rotation with the black hole horizon, along 1-dimensional subspaces – existence lines – of the Kerr 2-dimensional parameter space. They are zero modes of the superradiant instability. Non-linear Q-clouds, on the other hand, are also in synchronous rotation with the black hole horizon; but they exist on a 2-dimensional subspace, delimited by a minimal horizon angular velocity and by an appropriate existence line, wherein the non-linear terms become irrelevant and the Q-cloud reduces to a linear cloud. Thus, Q-clouds provide an example of scalar bound states around Kerr black holes which, generically, are not zero modes of the superradiant instability. We describe some physical properties of Q-clouds, whose backreaction leads to a new family of hairy black holes, continuously connected to the Kerr family.
Optical nonlinearity of liquid nanosuspensions: Kerr versus exponential model
Wright, E. M.; Lee, W. M.; Dholakia, K.; El-Ganainy, R.; Christodoulides, D. N.
2009-08-01
We report our experimental and theoretical progress towards elucidating the nonlinear optical response of nanosuspensions. To date, we have devised a fiber-optic variant of the Z-scan method to accurately measure the nonlinearity of liquid nanosuspensions. Furthermore, we shall show that the optical nonlinearity may be properly accounted theoretically by including both the virial coefficients for the soft-condensed matter system in addition to the exponential term, which does not account for particleparticle interactions, yielding an effective or renormalized Kerr effect in many cases.
Moyal phase-space analysis of nonlinear optical Kerr media
International Nuclear Information System (INIS)
Osborn, T A; Marzlin, Karl-Peter
2009-01-01
Nonlinear optical media of Kerr type are described by a particular version of an anharmonic quantum harmonic oscillator. The dynamics of this system can be described using the Moyal equations of motion, which correspond to a quantum phase-space representation of the Heisenberg equations of motion. For the Kerr system we derive exact solutions of the Moyal equations for an irreducible set of observables. These Moyal solutions incorporate the asymptotics of the classical limit in a simple, explicit form. An unusual feature of these solutions is that they exhibit periodic singularities in the time variable. These singularities are removed by the phase-space averaging required to construct the expectation value for an arbitrary initial state. Nevertheless, for strongly number-squeezed initial states the effects of the singularity remain observable.
Giant magneto-optical Kerr effect and universal Faraday effect in thin-film topological insulators.
Tse, Wang-Kong; MacDonald, A H
2010-07-30
Topological insulators can exhibit strong magneto-electric effects when their time-reversal symmetry is broken. In this Letter we consider the magneto-optical Kerr and Faraday effects of a topological insulator thin film weakly exchange coupled to a ferromagnet. We find that its Faraday rotation has a universal value at low frequencies θF=tan(-1)α, where α is the vacuum fine structure constant, and that it has a giant Kerr rotation θK=π/2. These properties follow from a delicate interplay between thin-film cavity confinement and the surface Hall conductivity of a topological insulator's helical quasiparticles.
Solookinejad, Gh.; Jabbari, M.; Sangachin, E. Ahmadi; Asadpour, S. H.
2018-01-01
In this paper, we discuss the transmission properties of weak probe laser field propagate through slab cavity with defect layer of carbon-nanotube quantum dot (CNT-QD) nanostructure. We show that due to spin-orbit coupling, the double electromagnetically induced transparency (EIT) windows appear and the giant Kerr nonlinearity of the intracavity medium can lead to manipulating of transmission coefficient of weak probe light. The thickness effect of defect layer medium has also been analyzed on transmission properties of probe laser field. Our proposed model may be useful for integrated photonics devices based on CNT-QD for applications in all-optical systems which require multiple EIT effect.
Nurhuda, M.; van Groesen, Embrecht W.C.
2005-01-01
We present a systematic study of filamentary ultrashort laser pulses in air, through numerical solutions of the nonlinear Schrödinger equation for various contributions of the delayed Kerr nonlinearity. The results show that a relatively larger contribution of the delayed Kerr nonlinearity will lead
Ahmad, S.; Ahmad, A.; Bacha, B. A.; Khan, A. A.; Abdul Jabar, M. S.
2017-12-01
Surface Plasmon Polaritons (SPPs) are theoretically investigated at the interface of a dielectric metal and gold. The output pulse from the dielectric is used as the input pulse for the generation of SPPs. The SPPs show soliton-like behavior at the interface. The solitary form of a SPP is maintained under the effects of Kerr nonlinearity, Doppler broadening and Fresnel dragging whereas its phase shift is significantly modified. A 0.3radian phase shift is calculated in the presence of both Kerr nonlinearity and Fresnel dragging in the absence of plasma motion. The phase shift is enhanced to 60radian due to the combined effect of Doppler broadening, Kerr nonlinearity and Fresnel dragging. The results may have significant applications in nano-photonics, optical tweezers, photovoltaic devices, plasmonster and sensing technology.
International Nuclear Information System (INIS)
Zhang Zaiyun; Liu Zhenhai; Miao Xiujin; Chen Yuezhong
2011-01-01
In this Letter, we investigate the perturbed nonlinear Schroedinger's equation (NLSE) with Kerr law nonlinearity. All explicit expressions of the bounded traveling wave solutions for the equation are obtained by using the bifurcation method and qualitative theory of dynamical systems. These solutions contain bell-shaped solitary wave solutions, kink-shaped solitary wave solutions and Jacobi elliptic function periodic solutions. Moreover, we point out the region which these periodic wave solutions lie in. We present the relation between the bounded traveling wave solution and the energy level h. We find that these periodic wave solutions tend to the corresponding solitary wave solutions as h increases or decreases. Finally, for some special selections of the energy level h, it is shown that the exact periodic solutions evolute into solitary wave solution.
Xiu, Xiao-Ming; Cui, Cen; Lin, Yan-Fang; Dong, Li; Dong, Hai-Kuan; Gao, Ya-Jun
2018-01-01
With the assistance of weak cross-Kerr nonlinear interaction between photons and coherent states via Kerr media, we propose a scheme to split and acquire quantum information with three-photon perfect W states. By means of a fault-tolerant circuit, the perfect W states are distributed to the participants without being affected by the collective noise. And on this basis we present a scheme for splitting and acquiring a single-photon state with the shared perfect W states. Together with the mature techniques of classical feed-forward, simple and available linear optical elements are applied in the procedure, afford enhancing the feasibility of the theoretical scheme proposed here.
Comparative Study of FDTD-Adopted Numerical Algorithms for Kerr Nonlinearities
DEFF Research Database (Denmark)
Maksymov, Ivan S.; Sukhorukov, Andrey A.; Lavrinenko, Andrei
2011-01-01
Accurate finite-difference time-domain (FDTD) modeling of optical pulse propagation in nonlinear media usually implies the use of auxiliary differential equation (ADE) techniques. The updating of electric field in full-vectorial 3-D ADE FDTD modeling of the optical Kerr effect and two-photon abso...... approaches. Such schemes can significantly reduce the CPU time for nonlinear computations, especially in 3-D models.......Accurate finite-difference time-domain (FDTD) modeling of optical pulse propagation in nonlinear media usually implies the use of auxiliary differential equation (ADE) techniques. The updating of electric field in full-vectorial 3-D ADE FDTD modeling of the optical Kerr effect and two...
Energy Technology Data Exchange (ETDEWEB)
Torres-Torres, C., E-mail: crstorres@yahoo.com.mx [Seccion de Estudios de Posgrado e Investigacion, ESIME-Z, Instituto Politecnico Nacional, Mexico, DF 07738 (Mexico); Garcia-Cruz, M.L. [Centro de Investigacion en Dispositivos Semiconductores, Benemerita Universidad Autonoma de Puebla, A. P. J-48, Puebla 72570, Mexico (Mexico); Castaneda, L., E-mail: luisca@sirio.ifuap.buap.mx [Instituto de Fisica, Benemerita Universidad Autonoma de Puebla, A. P. J-48, Puebla 72570, Mexico (Mexico); Rangel Rojo, R. [CICESE/Depto. de Optica, A. P. 360, Ensenada, BC 22860 (Mexico); Tamayo-Rivera, L. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Mexico, DF 01000 (Mexico); Maldonado, A. [Depto. de Ing. Electrica, CINVESTAV IPN-SEES, A. P. 14740, Mexico DF 07000 (Mexico); Avendano-Alejo, M., E-mail: imax_aa@yahoo.com.mx [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, A. P. 70-186, 04510, DF (Mexico); and others
2012-04-15
Chromium doped zinc oxide thin solid films were deposited on soda-lime glass substrates. The photoconductivity of the material and its influence on the optical behavior was evaluated. A non-alkoxide sol-gel synthesis approach was used for the preparation of the samples. An enhancement of the photoluminescence response exhibited by the resulting photoconductive films with embedded chromium nanoclusters is presented. The modification in the photoconduction induced by a 445 nm wavelength was measured and then associated with the participation of the optical absorptive response. In order to investigate the third order optical nonlinearities of the samples, a standard time-resolved Optical Kerr Gate configuration with 80 fs pulses at 830 nm was used and a quasi-instantaneous pure electronic nonlinearity without the contribution of nonlinear optical absorption was observed. We estimate that from the inclusion of Cr nanoclusters into the sample results a strong optical Kerr effect originated by quantum confinement. The large photoluminescence response and the important refractive nonlinearity of the photoconductive samples seem to promise potential applications for the development of multifunctional all-optical nanodevices. - Highlights: Black-Right-Pointing-Pointer Enhancement in photoluminescence for chromium doped zinc oxide films is presented. Black-Right-Pointing-Pointer A strong and ultrafast optical Kerr effect seems to result from quantum confinement. Black-Right-Pointing-Pointer Photoconductive properties for optical and optoelectronic functions were observed.
Stable one-dimensional periodic waves in Kerr-type saturable and quadratic nonlinear media
Energy Technology Data Exchange (ETDEWEB)
Kartashov, Yaroslav V [ICFO-Institut de Ciencies Fotoniques, and Department of Signal Theory and Communications, Universitat Politecnica de Catalunya, E-08034 Barcelona (Spain); Egorov, Alexey A [Physics Department, M V Lomonosov Moscow State University, 119899, Moscow (Russian Federation); Vysloukh, Victor A [Departamento de Fisica y Matematicas, Universidad de las Americas-Puebla, Santa Catarina Martir, 72820, Puebla, Cholula (Mexico); Torner, Lluis [ICFO-Institut de Ciencies Fotoniques, and Department of Signal Theory and Communications, Universitat Politecnica de Catalunya, E-08034 Barcelona (Spain)
2004-05-01
We review the latest progress and properties of the families of bright and dark one-dimensional periodic waves propagating in saturable Kerr-type and quadratic nonlinear media. We show how saturation of the nonlinear response results in the appearance of stability (instability) bands in a focusing (defocusing) medium, which is in sharp contrast with the properties of periodic waves in Kerr media. One of the key results discovered is the stabilization of multicolour periodic waves in quadratic media. In particular, dark-type waves are shown to be metastable, while bright-type waves are completely stable in a broad range of energy flows and material parameters. This yields the first known example of completely stable periodic wave patterns propagating in conservative uniform media supporting bright solitons. Such results open the way to the experimental observation of the corresponding self-sustained periodic wave patterns.
The Kerr nonlinearity of the beta-barium borate crystal
DEFF Research Database (Denmark)
Bache, Morten; Guo, Hairun; Zhou, Binbin
2013-01-01
A popular crystal for ultrafast cascading experiments is beta-barium-borate (β-BaB2O4, BBO). It has a decent quadratic nonlinear coefficient, and because the crystal is anisotropie it can be birefringence phase-matched for type I (oo → e) second-harmonic generation (SHG). For femtosecond experime......A popular crystal for ultrafast cascading experiments is beta-barium-borate (β-BaB2O4, BBO). It has a decent quadratic nonlinear coefficient, and because the crystal is anisotropie it can be birefringence phase-matched for type I (oo → e) second-harmonic generation (SHG). For femtosecond...
Kerr nonlinearity and plasmonic bistability in graphene nanoribbons
DEFF Research Database (Denmark)
Christensen, Thomas; Yan, Wei; Jauho, Antti-Pekka
2015-01-01
due to field enhancement, and the total nonlinearity is significantly affected by the field inhomogeneity of the plasmonic excitation. Finally, we discuss the emergence of a plasmonic bistability which exists for energies red-shifted relative to the linear resonance. Our results offer insights...
Entanglement of a nonlinear two two-level atoms interacting with deformed fields in Kerr medium
Abdel-Khalek, S.; El-Saman, Y. S.; Abdel-Aty, M.
2018-01-01
In this paper we investigate the entanglement dynamics between two two-level atoms interacting with two coherent fields in two spatially separated cavities which are filled with a Kerr-like medium. We examine the effect of nonlinear medium on the dynamical properties of entanglement and atomic occupation probabilities in the case of even and odd deformed coherent states. The results show that the deformed fields play important roles in the evolution of entanglement. Also, the results demonstrate that entanglement sudden death, sudden birth and long-distance can be controlled by the deformation and nonlinear parameters.
Theoretical description of light scattering by a collection of nonlinear Kerr particles
van Wonderen, A. J.
1992-05-01
We theoretically study multiple scattering of monochromatic light by a collection of spheres that can freely move in a background medium. The spheres contain an optical nonlinearity of the Kerr type. Employing diagrammatic methods we construct the iterative solution of the nonlinear scalar wave equation that describes the electromagnetic radiation field inside the sacttering medium. The ensuing diagrammatic series for the amplitude of the radiation field is averaged over all possible configurations of the scatterers. Subsequently, it is proved that the average amplitude satisfies a nonlinear equation that is the counterpart of the usual Dyson equation. For the case of point scatterers that do not absorb light we obtain solutions of our nonlinear Dyson equation. They predict that as a result of auto-Kerr and backscattering effects, the system can become unstable. Furthermore, we find that it is possible to bleach the scatterers. Finally, the influence of nonlinear absorption on the average amplitude is investigated. Nous présentons une étude théorique de la diffusion multiple d'une lumière monochromatique par un ensemble de sphères qui peuvent se déplacer librement dans un certain milieu. Les sphères possèdent une nonlinéarité optique de type Kerr. En utilisant les methodes diagrammatiques, nous construisons la solution itérative de l'équation d'onde scalaire nonlinéaire qui décrit le champ de rayonnement électromagnétique dans le milieu désordonné. On moyenne la série diagrammatique pour l'amplitude du champ rayonné sur toutes les configurations possibles des diffuseurs et on montre que l'amplitude moyenne obéit à une équation nonlinéaire qui est le pendant de l'équation de Dyson ordinaire. Dans le cas où les diffuseurs sont de petite taille et n'absorbent pas la lumière, nous trouvons des solutions de notre équation de Dyson nonlinéaire. Celles-ci montrent que, à la suite des effets auto-Kerr et des effets de la rétrodiffusion, le
DEFF Research Database (Denmark)
Bache, Morten; Guo, Hairun; Zhou, Binbin
2013-01-01
We study the anisotropic nature of the Kerr nonlinear response in a beta-barium borate (β-BaB2O4, BBO) nonlinear crystal. The focus is on determining the relevant χ(3) cubic tensor components that affect interaction of type I cascaded second-harmonic generation. Various experiments in the literat......We study the anisotropic nature of the Kerr nonlinear response in a beta-barium borate (β-BaB2O4, BBO) nonlinear crystal. The focus is on determining the relevant χ(3) cubic tensor components that affect interaction of type I cascaded second-harmonic generation. Various experiments...
Dalafi, A.; Naderi, M. H.
2017-04-01
An interacting cigar-shaped Bose-Einstein condensate (BEC) inside a driven optical cavity exhibits an intrinsic cross-Kerr (CK) nonlinearity due to the interaction with the optical mode of the cavity. Although the CK coupling is much weaker than those of the radiation pressure and the atom-atom interactions, it can affect the bistability behavior of the system when the intensity of the laser pump is strong enough. On the other hand, there is a competition between the CK nonlinearity and the atom-atom interaction so that the latter can neutralize the effect of the former. Furthermore, the CK nonlinearity causes the effective frequency of the Bogoliubov mode of the BEC as well as the quantum fluctuations of the system to be increased by increasing the cavity driving rate. However, in the dispersive interaction regime the effect of the CK nonlinearity is negligible. In addition, we show that by increasing the s -wave scattering frequency of atomic collisions one can generate a strong stationary quadrature squeezing in the Bogoliubov mode of the BEC.
Directory of Open Access Journals (Sweden)
Heng Wang
2016-01-01
Full Text Available By using the method of dynamical system, the exact travelling wave solutions of the higher-order nonlinear Schrödinger equation with derivative non-Kerr nonlinear terms are studied. Based on this method, all phase portraits of the system in the parametric space are given with the aid of the Maple software. All possible bounded travelling wave solutions, such as solitary wave solutions, kink and anti-kink wave solutions, and periodic travelling wave solutions, are obtained, respectively. The results presented in this paper improve the related previous conclusions.
Zolotovskii, I. O.; Korobko, D. A.; Lapin, V. A.
2014-01-01
The modulation instability in waveguides with high Kerr nonlinearity, characterised by a delayed nonlinear response, has been investigated with allowance for the self-steepening parameter and third-order dispersion. General expressions for the modulation gain are obtained. The influence of the waveguide parameters on the gain is analysed. It is shown that the joint effect of the delayed nonlinear response and negative nonlinearity dispersion leads to an increase in the modulation gain. The relations obtained are confirmed by numerical simulation. The results of this study can be used to design compact generators of high-frequency pulse trains.
Half-metallicity and giant magneto-optical Kerr effect in N-doped NaTaO3
Saeed, Yasir
2012-09-01
We use density functional theory and the modified Becke-Johnson (mBJ) approach to analyze the electronic and magneto-optical properties of N-doped NaTaO 3. The mBJ results show a half-metallic nature of NaTaO 2N, in contrast to the generalized gradient approximation. We find a giant polar Kerr rotation of 2.16°at 725 nm wave length (visible region), much higher than in other half-metallic perovskites and the prototypical half-metal PtMnSb. We explain the physical origin of this unexpected property. © 2012 Elsevier B.V. All rights reserved.
Yu, Xiang-xiang; Wang, Yu-hua
2014-01-13
Silver nanoparticles synthesized in a synthetic sapphire matrix were fabricated by ion implantation using the metal vapor vacuum arc ion source. The optical absorption spectrum of the Ag: Al2O3 composite material has been measured. The analysis of the supercontinuum spectrum displayed the nonlinear refractive property of this kind of sample. Nonlinear optical refraction index was identified at 800 nm excitation using the Kerr-lens autocorrelation (KLAC) technique. The spectrum showed that the material possessed self-defocusing property (n(2) = -1.1 × 10(-15) cm(2)W). The mechanism of nonlinear refraction has been discussed.
Probabilistically cloning two single-photon states using weak cross-Kerr nonlinearities
International Nuclear Information System (INIS)
Zhang, Wen; Rui, Pinshu; Zhang, Ziyun; Yang, Qun
2014-01-01
By using quantum nondemolition detectors (QNDs) based on weak cross-Kerr nonlinearities, we propose an experimental scheme for achieving 1→2 probabilistic quantum cloning (PQC) of a single-photon state, secretly choosing from a two-state set. In our scheme, after a QND is performed on the to-be-cloned photon and the assistant photon, a single-photon projection measurement is performed by a polarization beam splitter (PBS) and two single-photon trigger detectors (SPTDs). The measurement is to judge whether the PQC should be continued. If the cloning fails, a cutoff is carried out and some operations are omitted. This makes our scheme economical. If the PQC is continued according to the measurement result, two more QNDs and some unitary operations are performed on the to-be-cloned photon and the cloning photon to achieve the PQC in a nearly deterministic way. Our experimental scheme for PQC is feasible for future technology. Furthermore, the quantum logic network of our PQC scheme is presented. In comparison with similar networks, our PQC network is simpler and more economical. (paper)
International Nuclear Information System (INIS)
Lee, Yong Woo; Cha, Yong Ho; Rhee, Yong Joo; Yoo, Byung Duk; Lee, Byoung Chul
2004-01-01
We have numerically analyzed the effect of soft-aperture Kerr-lens mode locking in Ti:sapphire laser cavities. Because the Kerr-lens effect depends on the intracavitiy power, we used nonlinear ABCD-matrix to calculated the power-dependent beam mode inside a cavity. In soft-aperture Kerr-lens mode locking, the Kerr-lens effect is strongly dependent on the position of the crystal, the separation of two curved mirrors, and the cavity length. Figure 1 is the schematic of the Ti:sapphire laser cavity used in our calculation. It consists of a Ti:sapphire crystal (Kerr medium), two curved mirrors, and flat mirrors. Lc is the Ti:sapphire crystal length, D1 the length between M1 and M3, D2 the length between M2 and M4, L1 the length between the crystal and M1, and L2 the length between crystal and M2
Arianfard, Hamed; Khajeheian, Bahareh; Ghayour, Rahim
2017-12-01
We have proposed and numerically investigated two plasmonic structures for bandpass and band-stop filters. The bandpass filter is composed of two metal-insulator-metal (MIM) waveguides coupled to each other by a nonlinear rectangular nanocavity. The band-stop filter consists of an MIM waveguide side coupled to a Kerr-type nonlinear rectangular nanocavity. The optical filtering effect is verified by two-dimensional (2-D) finite-difference time-domain (FDTD) simulations. It is demonstrated that based on optical nonlinearity we can easily make the proposed filters tunable by properly adjusting the intensity of incident light without changing the dimensions of the structures. The simulation results revealed that within the transmission spectrum, the selected central wavelength and the bandwidth of the filter can be tuned by the input signal intensity. The proposed structures are suitable to be used as highly dense integrated optical circuits, where limitations on the dimensions of the filter structure are vital.
Chai, Jun; Tian, Bo; Zhen, Hui-Ling; Sun, Wen-Rong; Liu, De-Yin
2017-04-01
Effects of quantic nonlinearity on the propagation of the ultrashort optical pulses in a non-Kerr medium, like an optical fiber, can be described by a perturbed nonlinear Schrödinger equation with the power law nonlinearity, which is studied in this paper from a planar-dynamic-system view point. We obtain the equivalent two-dimensional planar dynamic system of such an equation, for which, according to the bifurcation theory and qualitative theory, phase portraits are given. Through the analysis of those phase portraits, we present the relations among the Hamiltonian, orbits of the dynamic system and types of the analytic solutions. Analytic expressions of the periodic-wave solutions, kink- and bell-shaped solitary-wave solutions are derived, and we find that the periodic-wave solutions can be reduced to the kink- and bell-shaped solitary-wave solutions.
Hopkins, James; Gaudette, Jamie; Mehta, Priyanth
2013-10-01
With the advent of digital signal processing (DSP) in optical transmitters and receivers, the ability to finely tune the ratio of pre and post dispersion compensation can be exploited to best mitigate the nonlinear penalties caused by the Kerr effect. A portion of the nonlinear penalty in optical communication channels has been explained by an increase in peak to average power ratio (PAPR) inherent in highly dispersed signals. The standard approach for minimizing these impairments applies 50% pre dispersion compensation and 50% post dispersion compensation, thereby decreasing average PAPR along the length of the cable, as compared with either 100% pre or post dispersion compensation. In this paper we demonstrate that simply considering the net accumulated dispersion, and applying 50/50 pre/post dispersion is not necessarily the best way to minimize PAPR and subsequent Kerr nonlinearities. Instead, we consider the cumulative dispersion along the entire length of the cable, and, taking into account this additional information, derive an analytic formula for the minimization of PAPR. Alignment with simulation and experimental measurements is presented using a commercially available 100Gb/s dual-polarization binary phase-shift-keying (DP-BPSK) coherent modem, with transmitter and receiver DSP. Measurements are provided from two different 5000km dispersion managed Submarine test-beds, as well as a 3800km terrestrial test-bed with a mixture of SMF-28 and TWRS optical fiber. This method is shown to deviate significantly from the conventional 50/50 method described above, in dispersion managed communications systems, and more closely aligns with results obtained from simulation and data collected from laboratory test-beds.
DEFF Research Database (Denmark)
Sackey, I.; Da Ros, Francesco; Jazayerifar, M.
2014-01-01
We present experimental and numerical investigations of Kerr nonlinearity compensation in a 400-km standard single-mode fiber link with distributed Raman amplification with backward pumping. A dual-pump polarization-independent fiber-based optical parametric amplifier is used for mid-link spectra...
Nurmohammadi, Tofiq; Abbasian, Karim; Yadipour, Reza
2018-03-01
In this paper, an all-optical plasmonic switch based on metal-insulator-metal (MIM) nanoplasmonic waveguide with a Kerr nonlinear ring resonator is introduced and studied. Two-dimensional simulations utilizing the finite-difference time-domain algorithm are used to demonstrate an apparent optical bistability and significant switching mechanisms (in enabled-low condition: T(ON/OFF) =21.9 and in enabled-high condition: T(ON/OFF) =24.9) of the signal light arisen by altering the pump-light intensity. The proposed all-optical switching demonstrates femtosecond-scale feedback time (90 fs) and then ultra-fast switching can be achieved. The offered all-optical switch may recognize potential significant applications in integrated optical circuits.
Control of Wave Propagation and Effect of Kerr Nonlinearity on Group Index
International Nuclear Information System (INIS)
Hazrat, Ali; Iftikhar, Ahmed; Ziauddin
2013-01-01
We use four-level atomic system and control the wave propagation via forbidden decay rate. The Raman gain process becomes dominant on electromagnetically induced transparency (EIT) medium by increasing the forbidden decay rate via increasing the number of atoms [G.S. Agarwal and T.N. Dey, Phys. Rev. A 74 (2006) 043805 and K. Harada, T. Kanbashi, and M. Mitsunaga, Phys. Rev. A 73 (2006) 013803]. The behavior of wave propagation is dramatically changed from normal (subluminal) to anomalous (superluminal) dispersion by increasing the forbidden decay rate. The system can also give a control over the group velocity of the light propagating through the medium via Kerr field. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
International Nuclear Information System (INIS)
Yu, Xiangxiang; Wang, Yuhua; Wang, Yumei
2014-01-01
The nonlinear refraction of a nickel doped α-Al 2 O 3 single crystal was measured with a 800 nm pulse using the Kerr-lens autocorrelation technique. The sample was fabricated by ion implantation using a metal vapor vacuum arc ion source. The value of the nonlinear refractive index, n 2 , of the sample was determined to be 7.9 × 10 −16 cm 2 W −1 . The mechanisms of nonlinear refraction of the bulk material and the nanoparticles have been discussed through the UV–vis spectrum and supercontinuum spectra. (paper)
Nonlinear, anisotropic, and giant photoconductivity in intrinsic and doped graphene
Singh, Ashutosh; Ghosh, Saikat; Agarwal, Amit
2018-01-01
We present a framework to calculate the anisotropic and nonlinear photoconductivity for two band systems with application to graphene. In contrast to the usual perturbative (second order in the optical field strength) techniques, we calculate photoconductivity to all orders in the optical field strength. In particular, for graphene, we find the photoresponse to be giant (at large optical field strengths) and anisotropic. The anisotropic photoresponse in graphene is correlated with polarization of the incident field, with the response being similar to that of a half-wave plate. We predict that the anisotropy in the simultaneous measurement of longitudinal (σx x) and transverse (σy x) photoconductivity, with four probes, offers a unique experimental signature of the photovoltaic response, distinguishing it from the thermal-Seebeck and bolometric effects in photoresponse.
Nonlinear self-focus of pulsed-wave beams in Kerr media
Energy Technology Data Exchange (ETDEWEB)
Judkins, Justin Boyd [Univ. of Arizona, Tucson, AZ (United States)
1992-01-01
A modified finite-difference time-domain method for solving Maxwell`s equations in nonlinear media is presented. This method allows for a finite response time to be incorporated in the medium, physically creating dispersion and absorption mechanisms. The technique models electromagnetic fields in two space dimensions and time and encompasses both the TE_{z} and TM_{z} set of decoupled field equations. Aspects of an ultra-short pulsed Gaussian beam are studied in a variety of linear and nonlinear environments to demonstrate that the methods developed here can be used efficaciously in the modeling of pulses in complex problem space geometries even when nonlinearities are present.
Abdalla, M. Sebawe; Khalil, E. M.; Obada, A. S.-F.
2017-08-01
The problem of the codirectional Kerr coupler has been considered several times from different point of view. In the present paper we introduce the interaction between a two-level atom and the codirectional Kerr nonlinear coupler in terms of su (2 ) Lie algebra. Under certain conditions we have adjusted the Kerr coupler and consequently we have managed to handle the problem. The wave function is obtained by using the evolution operator where the Heisnberg equation of motion is invoked to get the constants of the motion. We note that the Kerr parameter χ as well as the quantum number j plays the role of controlling the atomic inversion behavior. Also the maximum entanglement occurs after a short period of time when χ = 0. On the other hand for the entropy and the variance squeezing we observe that there is exchange between the quadrature variances. Furthermore, the variation in the quantum number j as well as in the parameter χ leads to increase or decrease in the number of fluctuations. Finally we examined the second order correlation function where classical and nonclassical phenomena are observed.
Energy Technology Data Exchange (ETDEWEB)
AbdelMalek, Fathi; Aroua, Walid [National Institute of Applied Science and Technology, University of Carthage, Tunis (Tunisia); Haxha, Shyqyri [Computer Science and Technology Department, Bedfordshire University, Luton (United Kingdom); Flint, Ian [Selex ES Ltd, Luton, Bedfordshire (United Kingdom)
2016-08-15
In this research work, we propose all-optical transistor based on metallic nanoparticle cross-chains geometry. The geometry of the proposed device consists of two silver nanoparticle chains arranged along the x- and z-axis. The x-chain contains a Kerr nonlinearity, the source beam is set at the left side of the later, while the control beam is located at the top side of the z-chain. The control beam can turn ON and OFF the light transmission of an incoming light. We report a theoretical model of a very small all-optical transistor proof-of-concept made of optical 'light switching light' concept. We show that the transmission efficiency strongly depends on the control beam and polarization of the incoming light. We investigate the influence of a perfect reflector and reflecting substrate on the transmission of the optical signal when the control beam is turned ON and OFF. These new findings make our unique design a potential candidate for future highly-integrated optical information processing chips. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Design of triply-resonant microphotonic parametric oscillators based on Kerr nonlinearity.
Zeng, Xiaoge; Popović, Miloš A
2014-06-30
We propose optimal designs for triply-resonant optical parametric oscillators (OPOs) based on degenerate four-wave mixing (FWM) in microcavities. We show that optimal designs in general call for different external coupling to pump and signal/idler resonances. We provide a number of normalized performance metrics including threshold pump power and maximum achievable conversion efficiency for OPOs with and without two-photon (TPA) and free-carrier absorption (FCA). We find that the maximum achievable conversion efficiency is bound to an upper limit by nonlinear and free-carrier losses independent of pump power, while linear losses only increase the pump power required to achieve a certain conversion efficiency. The results of this work suggest unique advantages in on-chip implementations that allow explicit engineering of resonances, mode field overlaps, dispersion, and wavelength-and mode-selective coupling. We provide universal design curves that yield optimum designs, and give example designs of microring-resonator-based OPOs in silicon at the wavelengths 1.55 μm (with TPA) and 2.3 μm (no TPA) as well as in silicon nitride (Si(3)N(4)) at 1.55 μm. For typical microcavity quality factor of 10(6), we show that the oscillation threshold in excitation bus can be well into the sub-mW regime for silicon microrings and a few mW for silicon nitride microrings. The conversion efficiency can be a few percent when pumped at 10 times of the threshold. Next, based on our results, we suggest a family of synthetic "photonic molecule"-like, coupled-cavity systems to implement optimum FWM, where structure design for control of resonant wavelengths can be separated from that of optimizing nonlinear conversion efficiency, and where furthermore pump, signal, and idler coupling to bus waveguides can be controlled independently, using interferometric cavity supermode coupling as an example. Finally, consideration of these complex geometries calls for a generalization of the nonlinear
DEFF Research Database (Denmark)
Sackey, Isaac; Da Ros, Francesco; Karl Fischer, Johannes
2015-01-01
a dual-pump polarization-independent fiber-optic parametric amplifier and compared to digital backpropagation (DBP) compensation over up to 800-km in a dispersion-managed link. In the single-channel case, the use of the DBP algorithm outperformed the OPC with a Q-factor improvement of 0.9 dB after 800-km......We experimentally investigate Kerr nonlinearity mitigation of a 28-GBd polarization-multiplexed 16-QAM signal in a five-channel 50-GHz spaced wavelength-division multiplexing (WDM) system. Optical phase conjugation (OPC) employing the mid-link spectral inversion technique is implemented by using...
International Nuclear Information System (INIS)
Rashidian Vaziri, M R; Hajiesmaeilbaigi, F; Maleki, M H
2013-01-01
Knowing the Gaussian beam parameters, such as its radius of curvature and spot size during propagation in nonlinear Kerr media, is of paramount importance in describing the observable far-field diffraction ring patterns as well as in design and stability analysis of Kerr-lens mode-locked resonators. Specifically, the sign of the beam radius of curvature after exiting these media has been proposed to be of assistance in recognizing their optical nonlinearity sign through determining the type of diffraction ring pattern in the far field. In order to be able to trace the evolution of the beam parameters in the Gaussian beam formalism, we have used the common aberration-free theory. We have shown that the nonlinear propagation problem of a fundamental Gaussian beam in a Kerr medium with an intensity-dependent index of refraction can be handled by assuming a ducting index profile along the propagation direction. Knowing the familiar ABCD matrix of a duct, the evolution of the mentioned beam parameters can be traced during propagation using the ABCD law in Gaussian beam theory. We have validated our ducting model by comparing its results with the outcomes of one widely used and accepted model which has been known to yield consistent results when electronic optical nonlinearity prevails. We have shown that when thermal optical nonlinearity is dominant, as in diffraction ring observation experiments, our ducting model yields sensible results and should be used. Our model predicts that when the sign of the thermal nonlinearity and the beam radius of curvature on the entrance plane of the medium are positive, the sign of the beam radius of curvature on the exit plane may have either sign, depending on the medium thickness used in the experiment. Hence, two types of diffraction ring pattern may be obtained using the same medium with two different thicknesses and this may cast doubt on the validity of the methods proposing the detection of the optical nonlinearity signs by
Zamani, Mehdi; Hocini, Abdesselam
2018-03-01
In this work, we report on the theoretical study of one-dimensional magnetophotonic crystals (MPC) comprising of periodic dielectric structure Si/SiO and of silica matrix doped with cobalt-ferrite (CoFe2O4) magnetic nanoparticles as the only magnetic defect layer. Such structure can be prepared by sol-gel dip coating method that controls the thickness of each layer with nanometer level, hence, can overcome the problem of integration of the magneto-optical (MO) devices. We have studied the influence of the volume fraction (concentration of magnetic nanoparticles VF%) on the optical (reflectance, transmittance and absorption) and MO (Kerr rotation) responses in reflection-type one-dimensional MPCs. During investigation of the influence of magnetic nanoparticle's concentration, we found that giant Kerr rotations (even ≈135° for VF = 39%) can be obtained accompanied by large reflectance and low amounts for transmittance and absorption. We report on the demonstration of large MO quality factor and figure of merit in cobalt-ferrite magnetic nanoparticles in the infrared regime. Given the large Kerr rotation, high reflectance accompanied by low absorption and nearly zero transmittance of the 1D MPC containing cobalt-ferrite magnetic nanoparticles, large MO Q factor and figure of merit are obtained.
Zhang, Jian-Song; Zeng, Wei; Chen, Ai-Xi
2017-06-01
We study the influence of cross-Kerr (CK) coupling and optical parametric amplifier (OPA) on the effective frequency, damping, normal mode splitting, ground state cooling, and steady state entanglement of an optomechanical system formed by one fixed mirror and one movable mirror. The CK coupling could increase the damping of the movable mirror. The normal mode splitting of the output field is observed due to the CK coupling. The combination of the CK coupling and OPA decreases the minimum attainable phonon number and the effective temperature of the movable mirror. The amount of stationary entanglement between the mechanical and cavity modes can be enhanced by the weak CK coupling. In particular, we find the stationary entanglement becomes more robust against thermal fluctuations of the movable mirror in the presence of the weak CK coupling.
Dai, Chao-Qing; Fan, Yan; Wang, Yue-Yue; Zheng, Jun
2018-02-01
The (3 + 1)-dimensional generalized coupled nonlinear Schrödinger equation with electric and magnetic nonlinearities of Kerr type and self-steepening effects is studied, and bright and dark soliton solutions are derived. Based on these analytical solutions, dynamical behaviors of bright and dark solitons are discussed. The amplitudes, widths and velocities of bright and dark solitons are all constants determined by the self-steepening effect parameters SE, SH. The phase chirp of a bright soliton diminishes in the pulse front of y-direction, however, it increases in the pulse back edge of y-direction. On the contrary, the phase chirp of a dark soliton increases in the pulse front of y-direction, however, it diminishes in the pulse back edge of y-direction. The phase chirps of a bright and dark soliton both shift along positive y -axis as time goes on. Moreover, the stability of the solutions is discussed.
Giant X-ray nonlinearities in the kiloelectronvolt regime
International Nuclear Information System (INIS)
Racz, E.; Khan, S.F.; Borisov, A.B.; Poopalasingam, S.; McCorkindale, J.C.; Boguta, J.; Zhao, J.; Ward, S.J.; Longworth, J.W.; Illinois Inst. of Technology, Chicago, IL; Felder, A.E.; Illinois University, Chicago, IL; Rhodes, C.K.; Illinois University, Chicago, IL
2010-01-01
Complete text of publication follows. Copious Xe(M) (∼ 1 keV) and Xe(L) (∼ 4.5 keV) production induced by intense femtosecond 248 nm pulse excitation of Xe clusters is a well established phenomenon. Present studies of the characteristics of Xe(L) amplification in plasma channels have dramatically revealed the presence of very strong nonlinear dispersive and absorptive processes in the x-ray range that are illustrated in Figure 1. The dispersive nonlinearity is illustrated in panels (a) and (b) by the clear action of self-focusing. The corresponding absorptive nonlinearity is shown in panel (c); intense Xe(M) radiation at ∼ 1 keV produces Xe L-shell vacancies that generate corresponding Xe(L) emission, an observation requiring the absorption of a minimum of 5 ∼ 1 keV photons. Since the linear Kramers-Kroenig relation has a nonlinear extension, these two phenomena are in natural alliance. Fig. 1. Simultaneous single-pulse pinhole camera Xe(M) (∼ 1 keV) and Xe(L) (∼ 4.5 keV) images of x-ray production and propagation in a 248 nm driven channel in a Xe cluster medium produced with a 1.4 mm diameter circular nozzle. (a) Characteristic Xe(M) propagation illustrating both copious x-ray production and the self-focusing of the originally annular Xe(M) beam. (b) 3-D view of panel (a) illustrating the collapse of the annular configuration of the Xe(M) beam into a focused axial structure. The self-focusing action is developed in the Xe cluster medium in a region that is not directly excited by the 248 nm pulse. (c) Simultaneously recorded Xe(L) emission that spatially overlaps the image in panel (a). The use of a 7.5 μm thick Ti filter suppresses the Xe(M) signal by a factor of ∼ 10 6 ; hence, only the Xe(L) component is detected. This image demonstrates that sufficiently intense Xe(M) radiation can produce strong Xe(L) emission by a nonlinear coupling. Of particular significance is the Xe(L) production observed at the end of the channel with a maximum spatial
Giant-spin nonlinear response theory of magnetic nanoparticle hyperthermia: A field dependence study
Carrião, M. S.; Aquino, V. R. R.; Landi, G. T.; Verde, E. L.; Sousa, M. H.; Bakuzis, A. F.
2017-05-01
Understanding high-field amplitude electromagnetic heat loss phenomena is of great importance, in particular, in the biomedical field, because the heat-delivery treatment plans might rely on analytical models that are only valid at low field amplitudes. Here, we develop a nonlinear response model valid for single-domain nanoparticles of larger particle sizes and higher field amplitudes in comparison to the linear response theory. A nonlinear magnetization expression and a generalized heat loss power equation are obtained and compared with the exact solution of the stochastic Landau-Lifshitz-Gilbert equation assuming the giant-spin hypothesis. The model is valid within the hyperthermia therapeutic window and predicts a shift of optimum particle size and distinct heat loss field amplitude exponents, which is often obtained experimentally using a phenomenological allometric function. Experimental hyperthermia data with distinct ferrite-based nanoparticles and third harmonic magnetization data support the nonlinear model, which also has implications for magnetic particle imaging and magnetic thermometry.
Terahertz-induced Kerr effect in amorphous chalcogenide glasses
DEFF Research Database (Denmark)
Zalkovskij, Maksim; Strikwerda, Andrew; Iwaszczuk, Krzysztof
2013-01-01
We have investigated the terahertz-induced third-order (Kerr) nonlinear optical properties of the amorphous chalcogenide glasses As2S3 and As2Se3. Chalcogenide glasses are known for their high optical Kerr nonlinearities which can be several hundred times greater than those of fused silica. We us...
Directory of Open Access Journals (Sweden)
Yakup YÄ±ldÄ±rÄ±m
Full Text Available In this study, we perform the extended Kudryashov method to nonlinear SchrÃ¶dinger equation (NLSE with spatio-temporal dispersion that arises in a propagation of light in nonlinear optical fibers, planar waveguides, BoseâEinstein condensate theory. Four types of nonlinearity â Kerr law, power law, parabolic law and dual-power law â are being considered for the model. By using this scheme, the topological, singular soliton and rational solutions are obtained. In addition, some graphical simulations of solutions are provided.It is demonstrated that the proposed algorithm is effective and can be handled for many other nonlinear complex differential equations. Keywords: Solitons, Nonlinear SchrÃ¶dinger equation with spatio-temporal dispersion, Extended Kudryashovâs method
Complex Kerr geometry and nonstationary Kerr solutions
International Nuclear Information System (INIS)
Burinskii, Alexander
2003-01-01
In the frame of the Kerr-Schild approach, we consider the complex structure of Kerr geometry which is determined by a complex world line of a complex source. The real Kerr geometry is represented as a real slice of this complex structure. The Kerr geometry is generalized to the nonstationary case when the current geometry is determined by a retarded time and is defined by a retarded-time construction via a given complex world line of source. A general exact solution corresponding to arbitrary motion of a spinning source is obtained. The acceleration of the source is accompanied by a lightlike radiation along the principal null congruence. It generalizes to the rotating case, the known Kinnersley class of 'photon rocket' solutions
Raman-Kerr frequency combs in microresonators with normal dispersion.
Cherenkov, A V; Kondratiev, N M; Lobanov, V E; Shitikov, A E; Skryabin, D V; Gorodetsky, M L
2017-12-11
We generalize the coupled mode formalism to study the generation of frequency combs in microresonators with simultaneous Raman and Kerr nonlinearities and investigate an impact of the former on the formation of frequency combs and dynamics of platicons in the regime of the normal group velocity dispersion. We demonstrate that the Raman effect initiates generation of sidebands, which cascade further in four-wave mixing and reshape into the Raman-Kerr frequency combs. We reveal that the Raman scattering induces a strong instability of the platicon pulses associated with the Kerr effect and normal dispersion. This instability results in branching of platicons and complex spatiotemporal dynamics.
Shi, Liangyu; Srivastava, Abhishek Kumar; Chigrinov, Vladimir G.; Kwok, Hoi-Sing
2016-09-01
In this article, we review recently achieved Kerr effect progress in novel liquid crystal (LC) material: vertically aligned deformed helix ferroelectric liquid crystal (VADHFLC). With an increasing applied electric field, the induced inplane birefringence of LCs shows quadratic nonlinearity. The theoretical calculations and experimental details are illustrated. With an enhanced Kerr constant to 130 nm/V2, this VADHFLC cell can achieve a 2π modulation by a small efficient electric field with a fast response around 100 μs and thus can be employed in both display and photonics devices.
Manipulating Kerr effects in a superconducting cavity via a superconducting qubit
Albert, Victor V.; Kirchmair, Gerhard; Vlastakis, Brian; Leghtas, Zaki; Mirrahimi, Mazyar; Girvin, S. M.; Schoelkopf, R. J.; Jiang, Liang
2013-03-01
Typically, models of qubit-cavity interactions in superconducting circuits have included terms strictly linear in amplitude of the cavity modes. Due to ever-increasing experimental ability to realize larger coupling strengths, induced nonlinearities in the cavity contribute significantly to the dynamics and thus need to be accounted for. Such nonlinearities include interactions between the photon numbers of two cavity modes (cross-Kerr) and between a mode and itself (self-Kerr). Motivated by the recent experimental demonstration of self-Kerr in superconducting cavities, we investigate quantum control of Kerr effects via a dispersively coupled superconducting qubit, which not only enables us to enhance or suppress the Kerr coupling, but also opens the possibility to investigate higher order Kerr effects.
Directory of Open Access Journals (Sweden)
Z. W. Zhu
2014-03-01
Full Text Available The non-linear dynamic characteristics and optimal control of a giant magnetostrictive film (GMF subjected to in-plane stochastic excitation were studied. Non-linear differential items were introduced to interpret the hysteretic phenomena of the GMF, and the non-linear dynamic model of the GMF subjected to in-plane stochastic excitation was developed. The stochastic stability was analysed, and the probability density function was obtained. The condition of stochastic Hopf bifurcation and noise-induced chaotic response were determined, and the fractal boundary of the system's safe basin was provided. The reliability function was solved from the backward Kolmogorov equation, and an optimal control strategy was proposed in the stochastic dynamic programming method. Numerical simulation shows that the system stability varies with the parameters, and stochastic Hopf bifurcation and chaos appear in the process; the area of the safe basin decreases when the noise intensifies, and the boundary of the safe basin becomes fractal; the system reliability improved through stochastic optimal control. Finally, the theoretical and numerical results were proved by experiments. The results are helpful in the engineering applications of GMF.
Giant nonlinear response at a plasmonic nanofocus drives efficient four-wave mixing
Nielsen, Michael P.; Shi, Xingyuan; Dichtl, Paul; Maier, Stefan A.; Oulton, Rupert F.
2017-12-01
Efficient optical frequency mixing typically must accumulate over large interaction lengths because nonlinear responses in natural materials are inherently weak. This limits the efficiency of mixing processes owing to the requirement of phase matching. Here, we report efficient four-wave mixing (FWM) over micrometer-scale interaction lengths at telecommunications wavelengths on silicon. We used an integrated plasmonic gap waveguide that strongly confines light within a nonlinear organic polymer. The gap waveguide intensifies light by nanofocusing it to a mode cross-section of a few tens of nanometers, thus generating a nonlinear response so strong that efficient FWM accumulates over wavelength-scale distances. This technique opens up nonlinear optics to a regime of relaxed phase matching, with the possibility of compact, broadband, and efficient frequency mixing integrated with silicon photonics.
Collapse suppression and soliton stabilization through nonlocality in bulk Kerr media
DEFF Research Database (Denmark)
Bang, Ole; Chemineau, E. T.; Krolikowski, Wieslaw
2000-01-01
We show that self-focusing cannot occur in bulk Kerr media with a nonlocal nonlinear response. We find the stationary solutions and show that nonlocality makes them stable. The results are verified numerically....
Electrets in soft materials: nonlinearity, size effects, and giant electromechanical coupling.
Deng, Qian; Liu, Liping; Sharma, Pradeep
2014-07-01
Development of soft electromechanical materials is critical for several tantalizing applications such as soft robots and stretchable electronics, among others. Soft nonpiezoelectric materials can be coaxed to behave like piezoelectrics by merely embedding charges and dipoles in their interior and assuring some elastic heterogeneity. Such so-called electret materials have been experimentally shown to exhibit very large electromechanical coupling. In this work, we derive rigorous nonlinear expressions that relate effective electromechanical coupling to the creation of electret materials. In contrast to the existing models, we are able to both qualitatively and quantitatively capture the known experimental results on the nonlinear response of electret materials. Furthermore, we show that the presence of another form of electromechanical coupling, flexoelectricity, leads to size effects that dramatically alter the electromechanical response at submicron feature sizes. One of our key conclusions is that nonlinear deformation (prevalent in soft materials) significantly enhances the flexoelectric response and hence the aforementioned size effects.
Electrets in soft materials: Nonlinearity, size effects, and giant electromechanical coupling
Deng, Qian; Liu, Liping; Sharma, Pradeep
2014-07-01
Development of soft electromechanical materials is critical for several tantalizing applications such as soft robots and stretchable electronics, among others. Soft nonpiezoelectric materials can be coaxed to behave like piezoelectrics by merely embedding charges and dipoles in their interior and assuring some elastic heterogeneity. Such so-called electret materials have been experimentally shown to exhibit very large electromechanical coupling. In this work, we derive rigorous nonlinear expressions that relate effective electromechanical coupling to the creation of electret materials. In contrast to the existing models, we are able to both qualitatively and quantitatively capture the known experimental results on the nonlinear response of electret materials. Furthermore, we show that the presence of another form of electromechanical coupling, flexoelectricity, leads to size effects that dramatically alter the electromechanical response at submicron feature sizes. One of our key conclusions is that nonlinear deformation (prevalent in soft materials) significantly enhances the flexoelectric response and hence the aforementioned size effects.
Black and gray Helmholtz-Kerr soliton refraction
International Nuclear Information System (INIS)
Sanchez-Curto, Julio; Chamorro-Posada, Pedro; McDonald, Graham S.
2011-01-01
Refraction of black and gray solitons at boundaries separating different defocusing Kerr media is analyzed within a Helmholtz framework. A universal nonlinear Snell's law is derived that describes gray soliton refraction, in addition to capturing the behavior of bright and black Kerr solitons at interfaces. Key regimes, defined by beam and interface characteristics, are identified, and predictions are verified by full numerical simulations. The existence of a unique total nonrefraction angle for gray solitons is reported; both internal and external refraction at a single interface is shown possible (dependent only on incidence angle). This, in turn, leads to the proposal of positive or negative lensing operations on soliton arrays at planar boundaries.
Advanced MOKE magnetometry in wide-field Kerr-microscopy
Soldatov, I. V.; Schäfer, R.
2017-10-01
The measurement of MOKE (Magneto-Optical Kerr Effect) magnetization loops in a wide-field Kerr microscope offers the advantage that the relevant domain images along the loop can be readily recorded. As the microscope's objective lens is exposed to the magnetic field, the loops are usually strongly distorted by non-linear Faraday rotations of the polarized light that occur in the objective lens and that are superimposed to the MOKE signal. In this paper, an experimental method, based on a motorized analyzer, is introduced which allows to compensate the Faraday contributions, thus leading to pure MOKE loops. A wide field Kerr microscope, equipped with this technology, works well as a laser-based MOKE magnetometer, additionally offering domain images and thus providing the basis for loop interpretation.
Selective sensitivity in Kerr microscopy
Soldatov, I. V.; Schäfer, R.
2017-07-01
A new technique for contrast separation in wide-field magneto-optical Kerr microscopy is introduced. Utilizing the light from eight light emitting diodes, guided to the microscope by glass fibers and being switched synchronously with the camera exposure, domain images with orthogonal in-plane sensitivity can be displayed simultaneously at real-time, and images with pure in-plane or polar contrast can be obtained. The benefit of this new method of contrast separation is demonstrated for Permalloy films, a NdFeB sinter magnet, and a cobalt crystal. Moreover, the new technique is shown to strongly enhance the sensitivity of Kerr microscopy by eliminating parasitic contrast contributions occurring in conventional setups. A doubling of the in-plane domain contrast and a sensitivity to Kerr rotations as low as 0.6 mdeg is demonstrated.
Selective sensitivity in Kerr microscopy.
Soldatov, I V; Schäfer, R
2017-07-01
A new technique for contrast separation in wide-field magneto-optical Kerr microscopy is introduced. Utilizing the light from eight light emitting diodes, guided to the microscope by glass fibers and being switched synchronously with the camera exposure, domain images with orthogonal in-plane sensitivity can be displayed simultaneously at real-time, and images with pure in-plane or polar contrast can be obtained. The benefit of this new method of contrast separation is demonstrated for Permalloy films, a NdFeB sinter magnet, and a cobalt crystal. Moreover, the new technique is shown to strongly enhance the sensitivity of Kerr microscopy by eliminating parasitic contrast contributions occurring in conventional setups. A doubling of the in-plane domain contrast and a sensitivity to Kerr rotations as low as 0.6 mdeg is demonstrated.
75 FR 57920 - Kerr-Philpott System
2010-09-23
... DEPARTMENT OF ENERGY Southeastern Power Administration Kerr-Philpott System AGENCY: Southeastern... Deputy Secretary In the Matter of: Southeastern Power Administration, Kerr-Philpott System Power Rates... proposed rate adjustment for the Kerr-Philpott System was published in the Federal Register February 22...
On Didelphis caudivolvula Kerr and Didelphis vulpecula Kerr
Jentink, F.A.
1885-01-01
Some months ago I was happy enough to procure for our library the rare Animal Kingdom written by Kerr. This autuhor described clearly two Phalangers under the names New-Holland descriptions have Opossum and Vulpine Opossum: these been overlooked by all the naturalist Who have studied the
Dynamical Formation of Kerr Black Holes with Synchronized Hair: An Analytic Model.
Herdeiro, Carlos A R; Radu, Eugen
2017-12-29
East and Pretorius have successfully evolved, using fully nonlinear numerical simulations, the superradiant instability of the Kerr black hole (BH) triggered by a massive, complex vector field. Evolutions terminate in stationary states of a vector field condensate synchronized with a rotating BH horizon. We show that these end points are fundamental states of Kerr BHs with synchronized Proca hair. Motivated by the "experimental data" from these simulations, we suggest a universal (i.e., field-spin independent), analytic model for the subset of BHs with synchronized hair that possess a quasi-Kerr horizon, applicable in the weak hair regime. Comparing this model with fully nonlinear numerical solutions of BHs with a synchronized scalar or Proca hair, we show that the model is accurate for hairy BHs that may emerge dynamically from superradiance, whose domain we identify.
Dynamical Formation of Kerr Black Holes with Synchronized Hair: An Analytic Model
Herdeiro, Carlos A. R.; Radu, Eugen
2017-12-01
East and Pretorius have successfully evolved, using fully nonlinear numerical simulations, the superradiant instability of the Kerr black hole (BH) triggered by a massive, complex vector field. Evolutions terminate in stationary states of a vector field condensate synchronized with a rotating BH horizon. We show that these end points are fundamental states of Kerr BHs with synchronized Proca hair. Motivated by the "experimental data" from these simulations, we suggest a universal (i.e., field-spin independent), analytic model for the subset of BHs with synchronized hair that possess a quasi-Kerr horizon, applicable in the weak hair regime. Comparing this model with fully nonlinear numerical solutions of BHs with a synchronized scalar or Proca hair, we show that the model is accurate for hairy BHs that may emerge dynamically from superradiance, whose domain we identify.
Kerr-effect analysis in a three-level negative index material under magneto cross-coupling
Boutabba, N.
2018-02-01
We discuss the feasibility of the Kerr effect in negative refractive index materials under magneto cross-coupling and reservoir interaction. The considered medium is a typical three-level atomic system where we derive both the refractive and the gain spectrum. The profiles are analyzed for a weak probe field, and for varying strengths of the strong control field. The considered scheme shows an enhancement of the Kerr nonlinearity which we attribute to the contribution of the electromagnetic components of the fields. For more realistic experimental conditions, we discuss the dependence of the Kerr effect on different thermal bath coupling constants.
Analysis of Kerr effect in resonator fiber optic gyros with triangular wave phase modulation.
Ying, D; Demokan, M S; Zhang, X; Jin, W
2010-01-20
We present an in-depth analysis of the Kerr effect in resonator fiber optic gyros (R-FOGs) based on triangular wave phase modulation. Formulations that relate gyro output to the rotation rate, the Kerr nonlinearity, and other fiber and gyro parameters are derived and used to study the effect of Kerr nonlinearity on the gyro performance. Numerical investigation shows that the Kerr effect results in a nonzero gyro output even when the gyro is at stationary, which is interpreted as an error in the measurement of rotation rate. This error was found to increase as the frequencies of the two triangular phase modulations deviate from each other, and is not zero even if the intensities of the two counterpropagating beams are exactly the same. For fixed frequencies of the triangular phase modulations, there exists an optimal intensity splitting ratio for the two counterpropagating beams, which leads to zero gyro error. Calculation shows that the measurement error due to the Kerr effect for an R-FOG with a hollow-core photonic bandgap fiber as the fiber loop can be one to two orders of magnitude smaller than an R-FOG with a conventional single mode fiber loop.
Pump induced normal mode splittings in phase conjugation in a Kerr ...
Indian Academy of Sciences (India)
Abstract. Phase conjugation in a Kerr nonlinear waveguide is studied with counter-propagating normally incident pumps and a probe beam at an arbitrary angle of incidence. Detailed numerical results for the specular and phase conjugated reflectivities are obtained with full account of pump depletion. For sufficient ...
Energy Technology Data Exchange (ETDEWEB)
Gomes, Clélio B.C., E-mail: cleliogomes@ufrb.edu.br [CETEC, Universidade Federal do Recôncavo da Bahia, 44380-000 Cruz das Almas, Bahia (Brazil); Almeida, Francisco A.G.; Souza, Andre M.C. [Departamento de Fisica, Universidade Federal de Sergipe, 49100-000 Sao Cristovao, Sergipe (Brazil)
2016-04-29
We have studied analytically the Jaynes–Cummings–Hubbard model for a one-dimensional optical lattice with the account of the Kerr-type nonlinearity under the fermionic approximation. We have found that an increase in the number of photons or in the detuning parameter favors the superfluid phase. We have also found that the nonlinear Kerr effect favors the Mott insulator phase, which is in agreement with experimental observations.
Stationary nonlinear Airy beams
International Nuclear Information System (INIS)
Lotti, A.; Faccio, D.; Couairon, A.; Papazoglou, D. G.; Panagiotopoulos, P.; Tzortzakis, S.; Abdollahpour, D.
2011-01-01
We demonstrate the existence of an additional class of stationary accelerating Airy wave forms that exist in the presence of third-order (Kerr) nonlinearity and nonlinear losses. Numerical simulations and experiments, in agreement with the analytical model, highlight how these stationary solutions sustain the nonlinear evolution of Airy beams. The generic nature of the Airy solution allows extension of these results to other settings, and a variety of applications are suggested.
Nonlinear Optics in AlGaAs on Insulator
DEFF Research Database (Denmark)
Pu, Minhao; Ottaviano, Luisa; Semenova, Elizaveta
2016-01-01
AlGaAs on insulator is a powerful nonlinear platform sporting a high effective nonlinearity and the possibility to fabricate complex designs. We will present low loss waveguides enabling efficient optical signal processing and Kerr comb generation.......AlGaAs on insulator is a powerful nonlinear platform sporting a high effective nonlinearity and the possibility to fabricate complex designs. We will present low loss waveguides enabling efficient optical signal processing and Kerr comb generation....
Nonlinearity management and diffraction management for the ...
Indian Academy of Sciences (India)
dimensional spatial solitons in Kerr media with periodically varying diffraction and nonlinearity has been analyzed in this paper using variational approach and numerical studies. Analytical expressions for soliton parameters have been derived using ...
Kerr scattering coefficients via isomonodromy
Energy Technology Data Exchange (ETDEWEB)
Cunha, Bruno Carneiro da [Departamento de Física, Universidade Federal de Pernambuco,50670-901, Recife, Pernambuco (Brazil); Novaes, Fábio [International Institute of Physics, Federal University of Rio Grande do Norte,Av. Odilon Gomes de Lima 1722, Capim Macio, Natal-RN 59078-400 (Brazil)
2015-11-23
We study the scattering of a massless scalar field in a generic Kerr background. Using a particular gauge choice based on the current conservation of the radial equation, we give a generic formula for the scattering coefficient in terms of the composite monodromy parameter σ between the inner and the outer horizons. Using the isomonodromy flow, we calculate σ exactly in terms of the Painlevé V τ-function. We also show that the eigenvalue problem for the angular equation (spheroidal harmonics) can be calculated using the same techniques. We use recent developments relating the Painlevé V τ-function to Liouville irregular conformal blocks to claim that this scattering problem is solved in the combinatorial sense, with known expressions for the τ-function near the critical points.
Energy Technology Data Exchange (ETDEWEB)
Bejarano, Cecilia; Guzman, Maria Jose [Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Ferraro, Rafael [Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Universidad de Buenos Aires, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina)
2015-02-01
Null tetrads are shown to be a valuable tool in teleparallel theories of modified gravity. We use them to prove that Kerr geometry remains a solution for a wide family of f(T) theories of gravity. (orig.)
Kerr Hollow Quarry Remediation Project
International Nuclear Information System (INIS)
Walker, K.L.
1993-01-01
The Kerr Hollow Quarry is a 3-acre flooded limestone quarry located near the Y-12 Facility on the Oak Ridge Reservation. The quarry was used in the 1940s as a source of construction material for the Department of Energy in Oak Ridge, Tennessee. Its use was discontinued in the early 1950s, and it was allowed to flood with water. The quarry presently has a maximum water depth of approximately 55 ft. During the period between the early 1950s until about 1988, the quarry was used for the treatment and disposal of a variety of materials including water-reactive, alkali metals, shock-sensitive chemicals, and compressed gas cylinders. For some of these materials, the treatment consisted of dropping the vessels containing the materials into the quarry from a high bluff located on one side of the quarry. The vessels were then punctured by gun shot, and the materials were allowed to react with the water and sink to the bottom of the quarry. Very few disposal records exist for the period from 1952 to 1962. The records after that time, from 1962 until 1988, indicate some 50 t of hazardous and nonhazardous materials were disposed of in the quarry. This report documents remediation efforts that have taken place at the quarry beginning in September 1990
International Nuclear Information System (INIS)
Castañeda, L; Torres-Torres, C; Rangel-Rojo, R; Tamayo-Rivera, L; Torres-Martínez, R
2012-01-01
A modification of the nonlinear refractive index exhibited by indium-doped zinc oxide thin solid films deposited by an ultrasonic spray pyrolysis technique, after strong femtosecond laser irradiation, is presented. We used a standard time-resolved optical Kerr gate configuration with 80 fs pulses at 830 nm in order to study the third-order optical nonlinearities of the samples. A significant enhancement of the optical Kerr response was obtained by intense femtosecond excitation, which induced a permanent bleaching in the sample. A quasi-instantaneous pure electronic nonlinearity without the contribution of nonlinear optical absorption was observed. There is a close relationship between the change in linear absorption induced in the indium-doped zinc oxide film after high-intensity irradiation and the strong third-order nonlinearity that develops in the irradiated film.
Hopfield-Kerr model and analogue black hole radiation in dielectrics
Belgiorno, F.; Cacciatori, S. L.; Dalla Piazza, F.; Doronzo, M.
2017-11-01
In the context of the interaction between the electromagnetic field and a dielectric dispersive lossless medium, we present a nonlinear version of the relativistically covariant Hopfield model, which is suitable for the description of a dielectric Kerr perturbation propagating in a dielectric medium. The nonlinearity is introduced in the Lagrangian through a self-interacting term proportional to the fourth power of the polarization field. We find an exact solution for the nonlinear equations describing a propagating perturbation in the dielectric medium. Furthermore, the presence of an analogue Hawking effect, as well as the thermal properties of the model, are discussed, confirming and improving the results achieved in the scalar case.
Soliton compression to few-cycle pulses by cascaded quadratic nonlinearities
DEFF Research Database (Denmark)
Bache, Morten; Moses, Jeffrey; Bang, Ole
2007-01-01
Theoretical and numerical investigation of pulse-compression in a nonlinear crystal is presented. SHG soliton number is introduced and show that compression only takes place when it is larger than the "usual" Kerr soliton number. Pulse compression with cascaded quadratic nonlinearities requires...... that the ratio of the SHG and Kerr soliton numbers N>1....
APPLIED OPTICS. Overcoming Kerr-induced capacity limit in optical fiber transmission.
Temprana, E; Myslivets, E; Kuo, B P-P; Liu, L; Ataie, V; Alic, N; Radic, S
2015-06-26
Nonlinear optical response of silica imposes a fundamental limit on the information transfer capacity in optical fibers. Communication beyond this limit requires higher signal power and suppression of nonlinear distortions to prevent irreversible information loss. The nonlinear interaction in silica is a deterministic phenomenon that can, in principle, be completely reversed. However, attempts to remove the effects of nonlinear propagation have led to only modest improvements, and the precise physical mechanism preventing nonlinear cancellation remains unknown. We demonstrate that optical carrier stability plays a critical role in canceling Kerr-induced distortions and that nonlinear wave interaction in silica can be substantially reverted if optical carriers possess a sufficient degree of mutual coherence. These measurements indicate that fiber information capacity can be notably increased over previous estimates. Copyright © 2015, American Association for the Advancement of Science.
Weakly nonparaxial effects on the propagation of (1+1)D spatial solitons in inhomogeneous Kerr media
Suryanto, A.; van Groesen, Embrecht W.C.; Hammer, Manfred
2005-01-01
The widely used approach to study the beam propagation in Kerr media is based on the slowly varying envelope approximation (SVEA) which is also known as the paraxial approximation. Within this approximation, the beam evolution is described by the nonlinear Schroedinger (NLS) equation. In this paper,
Boosting the Kerr geometry in an arbitrary direction
Balasin, Herbert; Nachbagauer, Herbert
1996-04-01
We construct ultrarelativistic Kerr geometries from their distributional energy - momentum tensors. The latter are obtained by boosting Kerr's distributional energy - momentum tensor in arbitrary directions, thereby generalizing previous work by the authors.
Few-cycle nonlinear mid-IR pulse generated with cascaded quadratic nonlinearities
DEFF Research Database (Denmark)
Bache, Morten; Liu, Xing; Zhou, Binbin
Generating few-cycle energetic and broadband mid-IR pulses is an urgent current challenge in nonlinear optics. Cascaded second-harmonic generation (SHG) gives access to an ultrafast and octave-spanning self-defocusing nonlinearity: when ΔkL >> 2π the pump experiences a Kerr-like nonlinear index...
Spatial Solitons and Induced Kerr Effects in Quasi-Phase-Matched Quadratic Media
DEFF Research Database (Denmark)
Clausen, Carl A. Balslev; Bang, Ole; Kivshar, Yu.S.
1997-01-01
We show that the evolution of the average intensity of cw beams in a quasi-phase-matched quadratic (or chi((2))) medium is strongly influenced by induced Kerr effects, such as self- and cross-phase modulation. We prove the existence of rapidly oscillating solitary waves (a spatial analog of the g...... of the guided-center soliton) supported by the quadratic and induced cubic nonlinearities....
Conical emission from laser filaments and higher-order Kerr effect in air.
Béjot, P; Kasparian, J
2011-12-15
We numerically investigate the conical emission (CE) from ultrashort laser filaments, both considering and disregarding the higher-order Kerr effect (HOKE). While the consideration of HOKE has almost no influence on the predicted CE from collimated beams, differences arise for tightly focused beams. This difference is attributed to the different relative contributions of the nonlinear focus and of the modulational instability over the whole filament length.
Searching for non-Kerr objects
Energy Technology Data Exchange (ETDEWEB)
Apostolatos, Theocharis A; Lukes-Gerakopoulos, Georgios [Section of Astrophysics, Astronomy, and Mechanics, Department of Physics, University of Athens, Panepistimiopolis Zografos GR15783, Athens (Greece); Contopoulos, George, E-mail: thapostol@phys.uoa.gr [Academy of Athens, Research Center for Astronomy, Soranou Efesiou 4, GR-11527, Athens (Greece)
2011-02-01
We suggest a method that could be used to discriminate a Kerr black hole from any other supermassive axisymmetric astrophysical object by analyzing the gravitational-wave signal from an extreme mass ratio inspiral (EMRI). The method is based on the quite distinct qualitative features that characterize a slightly nonintegrable system. According to the Poincare-Birkhoff theorem, whenever a resonance of frequencies arise in an axisymmetric perturbed Kerr metric, instead of the anticipated KAM curves of the integrable Kerr case, a Birkhoff chain of islands appears on a surface of sections. The orbits of this chain of islands have a fixed ratio of frequencies. The idea is to exploit this feature to check if the inspiraling low-mass object spends a finite interval of time to cross this resonance, while its orbit evolves adiabatically due to the radiation of gravitational waves.
Ergoregion in metamaterials mimicking a Kerr spacetime
Pires, D. G.; Rocha, J. C. A.; Brandão, P. A.
2018-02-01
We propose a simple singularity-free coordinate transformation that could be implemented in Maxwell’s equations in order to simulate one aspect of a Kerr black hole. Kerr black holes are known to force light to rotate in a predetermined direction inside the ergoregion. By making use of cosmological analogies and the theoretical framework of transformation optics, we have designed a metamaterial that can make light behave as if it is propagating around a rotating cosmological massive body. We present numerical simulations involving incident Gaussian beams interacting with the materials to verify our predictions. The ergoregion is defined through the dispersion curve of the off-axis permittivities components.
Tidal interactions with Kerr black holes
International Nuclear Information System (INIS)
Hiscock, W.A.
1977-01-01
The tidal deformation of an extended test body falling with zero angular momentum into a Kerr black hole is calculated. Numerical results for infall along the symmetry axis and in the equatorial plane of the black hole are presented for a range of values of a, the specific angular momentum of the black hole. Estimates of the tidal contribution to the gravitational radiation are also given. The tidal contribution in equatorial infall into a maximally rotating Kerr black hole may be of the same order as the center-of-mass contribution to the gravitational radiation
Normal-dispersion microresonator Kerr frequency combs
Directory of Open Access Journals (Sweden)
Xue Xiaoxiao
2016-06-01
Full Text Available Optical microresonator-based Kerr frequency comb generation has developed into a hot research area in the past decade. Microresonator combs are promising for portable applications due to their potential for chip-level integration and low power consumption. According to the group velocity dispersion of the microresonator employed, research in this field may be classified into two categories: the anomalous dispersion regime and the normal dispersion regime. In this paper, we discuss the physics of Kerr comb generation in the normal dispersion regime and review recent experimental advances. The potential advantages and future directions of normal dispersion combs are also discussed.
Kerr-Schild metrics revisited. Pt. 1
International Nuclear Information System (INIS)
Gergely, L.A.; Perjes, Z.
1993-04-01
The particular way Kerr-Schild metrics incorporate a congruence of null curves in space-time is a sure source of fascination. The Kerr-Schild pencil of metrics g ab +Δl a l b is investigated in the generic case when it maps an arbitrary vacuum space-time with metric g ab to a vacuum space-time. The theorem is proved that this generic case does not contain the shear-free subclass as a smooth limit. It is shown that one of the Kota-Perjes metrics is a solution in the shearing class. (R.P.) 15 refs
Finite escape fraction for ultrahigh energy collisions around Kerr
Indian Academy of Sciences (India)
We investigate the issue of observability of high-energy collisions around Kerr naked singularity and show that results are in contrast with the Kerr black hole case. We had shown that it would be possible to have ultrahigh energy collisions between the particles close to the location = M around the Kerr naked singularity if ...
Finite escape fraction for ultrahigh energy collisions around Kerr ...
Indian Academy of Sciences (India)
We investigate the issue of observability of high-energy collisions around Kerr naked singularity and show that results are in contrast with the Kerr black hole case. We had shown that it would be possible to have ultrahigh energy collisions between the particles close to the location = M around the Kerr naked singularity if ...
Finite escape fraction for ultrahigh energy collisions around Kerr ...
Indian Academy of Sciences (India)
Abstract. We investigate the issue of observability of high-energy collisions around Kerr naked singularity and show that results are in contrast with the Kerr black hole case. We had shown that it would be possible to have ultrahigh energy collisions between the particles close to the location r = M around the Kerr naked ...
Kerr black holes with scalar hair.
Herdeiro, Carlos A R; Radu, Eugen
2014-06-06
We present a family of solutions of Einstein's gravity minimally coupled to a complex, massive scalar field, describing asymptotically flat, spinning black holes with scalar hair and a regular horizon. These hairy black holes (HBHs) are supported by rotation and have no static limit. Besides mass M and angular momentum J, they carry a conserved, continuous Noether charge Q measuring the scalar hair. HBHs branch off from the Kerr metric at the threshold of the superradiant instability and reduce to spinning boson stars in the limit of vanishing horizon area. They overlap with Kerr black holes for a set of (M, J) values. A single Killing vector field preserves the solutions, tangent to the null geodesic generators of the event horizon. HBHs can exhibit sharp physical differences when compared to the Kerr solution, such as J/M^{2}>1, a quadrupole moment larger than J^{2}/M, and a larger orbital angular velocity at the innermost stable circular orbit. Families of HBHs connected to the Kerr geometry should exist in scalar (and other) models with more general self-interactions.
Higher dimensional Kerr-Schild spacetimes
Czech Academy of Sciences Publication Activity Database
Ortaggio, Marcello; Pravda, Vojtěch; Pravdová, Alena
2009-01-01
Roč. 26, č. 2 (2009), s. 1-28 ISSN 0264-9381 R&D Projects: GA AV ČR KJB100190702 Institutional research plan: CEZ:AV0Z10190503 Keywords : higher-dimensional gravity * Kerr-Schild class * Newman-Penrose formalism Subject RIV: BA - General Mathematics Impact factor: 3.029, year: 2009
Nonthermal nature of extremal Kerr black holes
Rothman, Tony
2000-01-01
Liberati, Rothman and Sonego have recently showed that objects collapsing into extremal Reissner-Nordstrom black holes do not behave as thermal objects at any time in their history. In particular, a temperature, and hence thermodynamic entropy, are undefined for them. I demonstrate that the analysis goes through essentially unchanged for Kerr black holes.
Innermost stable circular orbit of Kerr-MOG black hole
Energy Technology Data Exchange (ETDEWEB)
Lee, Hyun-Chul; Han, Yong-Jin [Soonchunhyang University, Department of Physics, Asan (Korea, Republic of)
2017-10-15
We study the innermost stable circular orbit (ISCO) of the metric of the Kerr black hole in modified gravity (Kerr-MOG black hole), which is one of the exact solutions of the field equation of modified gravity in the strong gravity regime. The Kerr-MOG metric is constructed; it is the commonly known Kerr metric in Boyer-Lindquist coordinates by adding a repulsive term like the Yukawa force, which is explained in quantum gravity. In this paper, we numerically calculate the circular orbit of a photon and the ISCO of a test particle of Kerr-MOG black holes. (orig.)
Nonlinear Fabry-Perot filled with CS2 and nitrobenzene
International Nuclear Information System (INIS)
Bischofberger, T.; Shen, Y.R.
1979-01-01
We have studied the characteristics of nonlinear Fabry-Perot filled with Kerr liquids CS 2 and nitorbenzene and found excellent agreement between theory and experiment. The transient behavior due to cavity-field buildup is discussed
Observation of quantum state collapse and revival due to the single-photon Kerr effect.
Kirchmair, Gerhard; Vlastakis, Brian; Leghtas, Zaki; Nigg, Simon E; Paik, Hanhee; Ginossar, Eran; Mirrahimi, Mazyar; Frunzio, Luigi; Girvin, S M; Schoelkopf, R J
2013-03-14
To create and manipulate non-classical states of light for quantum information protocols, a strong, nonlinear interaction at the single-photon level is required. One approach to the generation of suitable interactions is to couple photons to atoms, as in the strong coupling regime of cavity quantum electrodynamic systems. In these systems, however, the quantum state of the light is only indirectly controlled by manipulating the atoms. A direct photon-photon interaction occurs in so-called Kerr media, which typically induce only weak nonlinearity at the cost of significant loss. So far, it has not been possible to reach the single-photon Kerr regime, in which the interaction strength between individual photons exceeds the loss rate. Here, using a three-dimensional circuit quantum electrodynamic architecture, we engineer an artificial Kerr medium that enters this regime and allows the observation of new quantum effects. We realize a gedanken experiment in which the collapse and revival of a coherent state can be observed. This time evolution is a consequence of the quantization of the light field in the cavity and the nonlinear interaction between individual photons. During the evolution, non-classical superpositions of coherent states (that is, multi-component 'Schrödinger cat' states) are formed. We visualize this evolution by measuring the Husimi Q function and confirm the non-classical properties of these transient states by cavity state tomography. The ability to create and manipulate superpositions of coherent states in such a high-quality-factor photon mode opens perspectives for combining the physics of continuous variables with superconducting circuits. The single-photon Kerr effect could be used in quantum non-demolition measurement of photons, single-photon generation, autonomous quantum feedback schemes and quantum logic operations.
Nonlinear Michelson interferometer for improved quantum metrology
Luis, Alfredo; Rivas, Ángel
2015-01-01
We examine quantum detection via a Michelson interferometer embedded in a gas with Kerr nonlinearity. This nonlinear interferometer is illuminated by pulses of classical light. This strategy combines the robustness against practical imperfections of classical light with the improvement provided by nonlinear processes. Regarding ultimate quantum limits, we stress that, as a difference with linear schemes, the nonlinearity introduces pulse duration as a new variable into play along with the ene...
Directory of Open Access Journals (Sweden)
Alexander Burinskii
2013-01-01
Full Text Available The 4D Kerr geometry displays many wonderful relations with quantum world and, in particular, with superstring theory. The lightlike structure of fields near the Kerr singular ring is similar to the structure of Sen solution for a closed heterotic string. Another string, open and complex, appears in the complex representation of the Kerr geometry initiated by Newman. Combination of these strings forms a membrane source of the Kerr geometry which is parallel to the structure of M-theory. In this paper we give one more evidence of this relationship, emergence of the Calabi-Yau twofold (K3 surface in twistorial structure of the Kerr geometry as a consequence of the Kerr theorem. Finally, we indicate that the Kerr stringy system may correspond to a complex embedding of the critical N = 2 superstring.
Oscillating solitons in nonlinear optics
Indian Academy of Sciences (India)
... are derived, and the relevant properties and features of oscillating solitons are illustrated. Oscillating solitons are controlled by the reciprocal of the group velocity and Kerr nonlinearity. Results of this paper will be valuable to the study of dispersion-managed optical communication system and mode-locked fibre lasers.
Xu, Xingyuan; Wu, Jiayang; Shoeiby, Mehrdad; Nguyen, Thach G.; Chu, Sai T.; Little, Brent E.; Morandotti, Roberto; Mitchell, Arnan; Moss, David J.
2018-01-01
An arbitrary-order intensity differentiator for high-order microwave signal differentiation is proposed and experimentally demonstrated on a versatile transversal microwave photonic signal processing platform based on integrated Kerr combs. With a CMOS-compatible nonlinear micro-ring resonator, high quality Kerr combs with broad bandwidth and large frequency spacings are generated, enabling a larger number of taps and an increased Nyquist zone. By programming and shaping individual comb lines' power, calculated tap weights are realized, thus achieving a versatile microwave photonic signal processing platform. Arbitrary-order intensity differentiation is demonstrated on the platform. The RF responses are experimentally characterized, and systems demonstrations for Gaussian input signals are also performed.
International Nuclear Information System (INIS)
Leitch-Devlin, M.A.; Millar, T.J.; Williams, D.A.
1976-01-01
Infrared observations of the Orion nebula have been interpreted by Rowan-Robinson (1975) to imply the existence of 'giant' grains, radius approximately 10 -2 cm, throughout a volume about a parsec in diameter. Although Rowan-Robinson's model of the nebula has been criticized and the presence of such grains in Orion is disputed, the proposition is accepted, that they exist, and in this paper situations in which giant grains could arise are examined. It is found that, while a giant-grain component to the interstellar grain density may exist, it is difficult to understand how giant grains arise to the extent apparently required by the Orion nebula model. (Auth.)
Chong Li; Xiaoyong Hu; Hong Yang; Qihuang Gong
2017-01-01
We propose a scheme of unidirectional transmission in a 1D nonlinear topological photonic crystal based on the topological edge state and three order optical nonlinearity. The 1D photonic crystals consists of a nonlinear photonic crystal L and a linear photonic crystal R. In the backward direction, light is totally reflected for the photons transmission prohibited by the bandgap. While in the forward direction, light interacts with the nonlinear photonic crystal L by optical Kerr effect, brin...
The Kerr geometry, complex world lines and hyperbolic strings
International Nuclear Information System (INIS)
Burinskii, A.Ya.
1994-01-01
In the Lind-Newman representation the Kerr geometry is created by a source moving along an analytical complex world line. An equivalence of the complex world line and complex (hyperbolic) string is considered. Therefore the hyperbolic string may play the role of the complex source of the Kerr geometry. The Kerr solution with the complex string source acquires Regge behavior of the angular momentum. (orig.)
Magneto-optical Kerr effect studies with classical electromagnetic theory
Ma, Rui-Can; Gao, Ling-Ling; Zhang, Ting; Jin, Yi
2017-08-01
Employing the basic law of electromagnetic wave propagation with the constitutive relation of ideal ferromagnetic medium, the magneto-optical Kerr effect of linearly polarized plane wave on the surface of ideal ferromagnetic medium is studied. We also discuss the change law of the Kerr rotation angle with the incident angle and magnetic-field strength in detail, which can provide crucial information for the applications of the magneto-optical Kerr effect in many fields.
Huang, T W; Zhou, C T; He, X T
2013-05-01
Plasma defocusing and higher-order Kerr effects on multiple filamentation and pattern formation of ultrashort laser pulse propagation in air are investigated. Linear analyses and numerical results show that these two saturable nonlinear effects can destroy the coherent evolution of the laser field, and small-scale spatial turbulent structures rapidly appear. For the two-dimensional case, numerical simulations show that blow-up-like solutions, spatial chaos, and pseudorecurrence can appear at higher laser intensities if only plasma defocusing is included. These complex patterns result from the stochastic evolution of the higher- or shorter-wavelength modes of the laser light spectrum. From the viewpoint of nonlinear dynamics, filamentation can be attributed to the modulational instability of these spatial incoherent localized structures. Furthermore, filament patterns associated with multiphoton ionization of the air molecules with and without higher-order Kerr effects are compared.
The band structures of three-dimensional nonlinear plasma photonic crystals
Zhang, Hai-Feng
2018-01-01
In this paper, the properties of the photonic band gaps (PBGs) for three-dimensional (3D) nonlinear plasma photonic crystals (PPCs) are theoretically investigated by the plane wave expansion method, whose equations for calculations also are deduced. The configuration of 3D nonlinear PPCs is the Kerr nonlinear dielectric spheres (Kerr effect is considered) inserted in the plasma background with simple-cubic lattices. The inserted dielectric spheres are Kerr nonlinear dielectrics whose relative permittivities are the functions of the external light intensity. Three different Kerr nonlinear dielectrics are considered, which can be expressed as the functions of space coordinates. The influences of the parameters for the Kerr nonlinear dielectrics on the PBGs also are discussed. The calculated results demonstrate that the locations, bandwidths and number of PBGs can be manipulated with the different Kerr nonlinear dielectrics. Compared with the conventional 3D dielectric PCs and PPCs with simple-cubic lattices, the more PBGs or larger PBG can be achieved in the 3D nonlinear PPCs. Those results provide a new way to design the novel devices based on the PPCs.
The band structures of three-dimensional nonlinear plasma photonic crystals
Directory of Open Access Journals (Sweden)
Hai-Feng Zhang
2018-01-01
Full Text Available In this paper, the properties of the photonic band gaps (PBGs for three-dimensional (3D nonlinear plasma photonic crystals (PPCs are theoretically investigated by the plane wave expansion method, whose equations for calculations also are deduced. The configuration of 3D nonlinear PPCs is the Kerr nonlinear dielectric spheres (Kerr effect is considered inserted in the plasma background with simple-cubic lattices. The inserted dielectric spheres are Kerr nonlinear dielectrics whose relative permittivities are the functions of the external light intensity. Three different Kerr nonlinear dielectrics are considered, which can be expressed as the functions of space coordinates. The influences of the parameters for the Kerr nonlinear dielectrics on the PBGs also are discussed. The calculated results demonstrate that the locations, bandwidths and number of PBGs can be manipulated with the different Kerr nonlinear dielectrics. Compared with the conventional 3D dielectric PCs and PPCs with simple-cubic lattices, the more PBGs or larger PBG can be achieved in the 3D nonlinear PPCs. Those results provide a new way to design the novel devices based on the PPCs.
The geometry of Kerr black holes
O'Neill, Barrett
2014-01-01
This unique monograph by a noted UCLA professor examines in detail the mathematics of Kerr black holes, which possess the properties of mass and angular momentum but carry no electrical charge. Suitable for advanced undergraduates and graduate students of mathematics, physics, and astronomy as well as professional physicists, the self-contained treatment constitutes an introduction to modern techniques in differential geometry. The text begins with a substantial chapter offering background on the mathematics needed for the rest of the book. Subsequent chapters emphasize physical interpretation
Rotating Black Holes and the Kerr Metric
Kerr, Roy Patrick
2008-10-01
Since it was first discovered in 1963 the Kerr metric has been used by relativists as a test-bed for conjectures on worm-holes, time travel, closed time-like loops, and the existence or otherwise of global Cauchy surfaces. More importantly, it has also used by astrophysicists to investigate the effects of collapsed objects on their local environments. These two groups of applications should not be confused. Astrophysical Black Holes are not the same as the Kruskal solution and its generalisations.
Korteweg-de Vries description of Helmholtz-Kerr dark solitons
International Nuclear Information System (INIS)
Christian, J M; McDonald, G S; Chamorro-Posada, P
2006-01-01
A wide variety of different physical systems can be described by a relatively small set of universal equations. For example, small-amplitude nonlinear Schroedinger dark solitons can be described by a Korteweg-de Vries (KdV) equation. Reductive perturbation theory, based on linear boosts and Gallilean transformations, is often employed to establish connections to and between such universal equations. Here, a novel analytical approach reveals that the evolution of small-amplitude Helmholtz-Kerr dark solitons is also governed by a KdV equation. This broadens the class of nonlinear systems that are known to possess KdV soliton solutions, and provides a framework for perturbative analyses when propagation angles are not negligibly small. The derivation of this KdV equation involves an element that appears new to weakly nonlinear analyses, since transformations are required to preserve the rotational symmetry inherent to Helmholtz-type equations
The ultrarelativistic Kerr geometry and its energy-momentum tensor
Balasin, Herbert; Nachbagauer, Herbert
1995-03-01
The ultrarelativistic limit of the Schwarzschild and the Kerr-geometry together with their respective energy-momentum tensors is derived. The approach is based on tensor-distributions making use of the underlying Kerr-Schild structure, which remains stable under the ultrarelativistic boost.
Kerr-effect enhancement in amorphous GdFe films
International Nuclear Information System (INIS)
Urner-Wille, M.; Velde, T.S. te; Engen, P.G. van
1978-01-01
Experimental investigations of amorphous ferrimagnetic GdFe films with CeO 2 coatings of various thicknesses have been performed. It could be shown that in general an increase in Kerr rotation was accompanied by a decrease in reflectionity by the CeO 2 coatings. The results indicate an enhancement of the magneto-optic Kerr effects
Giant anomalous self-steepening in photonic crystal waveguides
DEFF Research Database (Denmark)
Husko, Chad; Colman, Pierre
2015-01-01
CWGs) is largely determined by the geometrical parameters of the structure and is consequently tunable over a wide range. Here we show group-velocity (group-index) modulation leads to a previously unexplored physical mechanism for generating self-steepening. Further, we demonstrate that periodic media such as Ph......Self-steepening of optical pulses arises due to the dispersive contribution of the effective Kerr nonlinearity. In typical structures this response is on the order of a few femtoseconds with a fixed frequency response. In contrast, the effective Kerr nonlinearity in photonic crystal waveguides (Ph......CWGs can exhibit self-steepening coefficients two orders of magnitude larger than typical systems. At these magnitudes the self-steepening strongly affects the nonlinear pulse dynamics even for picosecond pulses. Due to interaction with additional higher-order nonlinearities in the semiconductor materials...
Othman, Anas; Yevick, David
2018-01-01
The interaction of a N-type four-level atom with a single field in the presence of an intensity-dependent coupling in a nonlinear Kerr medium is investigated. The exact analytic solution is obtained in the case that the atom and electromagnetic field are initially in a higher excited state and a coherent state, respectively. It is then demonstrated that effects such as nonclassical light generation, degree of entanglement stabilization, Kerr medium nonclassical control, and squeezed light are can be more efficiently implemented within this four-level framework than in many competing procedures. Additionally, inversion, linear entropy, Mandel Q-parameter and normal squeezing dynamics are examined.
Hawking radiation as tunneling from the Kerr and Kerr-Newman black holes
International Nuclear Information System (INIS)
Jiang Qingqan; Wu Shuangqing; Cai Xu
2006-01-01
Recent work, which treats the Hawking radiation as a semiclassical tunneling process at the horizon of the Schwarzschild and Reissner-Nordstroem spacetimes, indicates that the exact radiant spectrum is no longer pure thermal after considering the black hole background as dynamical and the conservation of energy. In this paper, we extend the method to investigate Hawking radiation as massless particles tunneling across the event horizon of the Kerr black hole and that of charged particles from the Kerr-Newman black hole by taking into account the energy conservation, the angular momentum conservation, and the electric charge conservation. Our results show that when self-gravitation is considered, the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum, but is consistent with an underlying unitary theory
Bueno, Pablo; Cano, Pablo A.; Goelen, Frederik; Hertog, Thomas; Vercnocke, Bert
2018-01-01
Structure at the horizon scale of black holes would give rise to echoes of the gravitational wave signal associated with the postmerger ringdown phase in binary coalescences. We study the waveform of echoes in static and stationary, traversable wormholes in which perturbations are governed by a symmetric effective potential. We argue that echoes are dominated by the wormhole quasinormal frequency nearest to the fundamental black hole frequency that controls the primary signal. We put forward an accurate method to construct the echoes' waveform(s) from the primary signal and the quasinormal frequencies of the wormhole, which we characterize. We illustrate this in the static Damour-Solodukhin wormhole and in a new, rotating generalization that approximates a Kerr black hole outside the throat. Rotation gives rise to a potential with an intermediate plateau region that breaks the degeneracy of the quasinormal frequencies. Rotation also leads to late-time instabilities that, however, fade away for small angular momentum.
Solitons in nonlocal nonlinear media: Exact solutions
DEFF Research Database (Denmark)
Krolikowski, Wieslaw; Bang, Ole
2001-01-01
We investigate the propagation of one-dimensional bright and dark spatial solitons in a nonlocal Kerr-like media, in which the nonlocality is of general form. We find an exact analytical solution to the nonlinear propagation equation in the case of weak nonlocality. We study the properties...... of these solitons and show their stability....
Cardona-Osuna, M E; Avila-Vergara, M A; Peraza-Garay, F; Meneses-Valderrama, V; Flores-Pompa, E; Corrales-López, A
2016-08-01
In Mexico, the prevalence of caesarean section is 40.9% in the health sector, the techniques used are the traditional Pfannenstiel-Kerr and Kerr-half infraumbilical and little experience with this new technique Misgav-Ladach modified. To compare pregnancy outcomes (surgical and fetal extraction time, bleeding, postoperative pain, surgical wound infection, maternal and fetal death) caesarean section techniques modified Misgav-Ladach, Pfannenstiel-Kerr and infraumbilical. Clinical trial in primiparous women with term pregnancy treated at the Medical Unit of High Specialty 23 of the Mexican Social Security Institute, Monterrey, Nuevo Leon, Mexico. Misgav-Ladach caesarean Caesarean modified and Kerr, the latter subdivided into two groups: infraumbilical Pfannenstiel incision and incision half-Kerr two groups patients were randomized. 137 gilts were studied, with term pregnancy and BMI between 19 and 24.9 kg / m2. Caesarean modified Misgav-Ladach 68 patients and 69 classical Kerr (35 Pfannenstiel-Kerr and 34 infraumbilical) was performed. The surgical time in minutes was lower with modified Misgav-Ladach: 27.8 ± 8.0, Pfannenstiel-Kerr recorded 51.7 ± 12.1 and 12.0 ± infraumbilical media48.3 (p = 0.000). The time in seconds fetal extraction was lower in modified Misgav-Ladach: 96.2 ± 68.3, 474.9 ± Pfannenstiel-Kerr 294.1 and 423.2 ± 398.6 infraumbilical (p = 0.000). The trasoperatory milliliters bleeding was lower with modified Misgav-Ladach: 298.5 ± 57.3, 354.3 ± Pfannenstiel-Kerr 98.0 and 355.9 ± 110.6 infraumbilical (p = 0.001). Postoperative pain assessed with the visual analog scale in the first 24 hours was lower with modified Misgav-Ladach: 4.4 ± 1.9, 5.7 ± Pfannenstiel-Kerr and IK 2.1 6.1 ± 2.0 (p = 0.000). The start of the oral route and ambulation Nwas soon comparing modified Misgav-Ladach against Pfannenstiel-Kerr and Kerr-infraumbilical (p = 0.000). The prevalence of fever was 5.9% with modified Misgav-Ladach, 5.9% Pfannenstiel-Kerr and 32
The zero mass limit of Kerr and Kerr-(anti-)de-Sitter space-times: exact solutions and wormholes
Birkandan, T.; Hortaçsu, M.
2018-03-01
Heun-type exact solutions emerge for both the radial and the angular equations for the case of a scalar particle coupled to the zero mass limit of both the Kerr and Kerr-(anti)de-Sitter spacetime. Since any type D metric has Heun-type solutions, it is interesting that this property is retained in the zero mass case. This work further refutes the claims that M going to zero limit of the Kerr metric is both locally and globally the same as the Minkowski metric.
Nonlinear Optics and Applications
Abdeldayem, Hossin A. (Editor); Frazier, Donald O. (Editor)
2007-01-01
Nonlinear optics is the result of laser beam interaction with materials and started with the advent of lasers in the early 1960s. The field is growing daily and plays a major role in emerging photonic technology. Nonlinear optics play a major role in many of the optical applications such as optical signal processing, optical computers, ultrafast switches, ultra-short pulsed lasers, sensors, laser amplifiers, and many others. This special review volume on Nonlinear Optics and Applications is intended for those who want to be aware of the most recent technology. This book presents a survey of the recent advances of nonlinear optical applications. Emphasis will be on novel devices and materials, switching technology, optical computing, and important experimental results. Recent developments in topics which are of historical interest to researchers, and in the same time of potential use in the fields of all-optical communication and computing technologies, are also included. Additionally, a few new related topics which might provoke discussion are presented. The book includes chapters on nonlinear optics and applications; the nonlinear Schrodinger and associated equations that model spatio-temporal propagation; the supercontinuum light source; wideband ultrashort pulse fiber laser sources; lattice fabrication as well as their linear and nonlinear light guiding properties; the second-order EO effect (Pockels), the third-order (Kerr) and thermo-optical effects in optical waveguides and their applications in optical communication; and, the effect of magnetic field and its role in nonlinear optics, among other chapters.
Ellipsoidal space-times, sources for the Kerr metric
International Nuclear Information System (INIS)
Krasinski, A.
1978-01-01
The paper develops a systematic derivation of the Kerr metric and its possible sources in a clear geometric manner. It starts with a concise account of previous attempts at constructing an interior Kerr solution. Then a treatment of stationary-axisymmetric space-times, specially fitted to the needs of the following analysis, is presented. A new notion of an ellipsoidal space-time is introduced: it is a space-time in which local rest 3-spaces of some observers split naturally into congruences of concentric and coaxial ellipsoids. It is shown that these 3-spaces are natural spaces to consider the ellipsoidal figures of equilibrium. The investigation is carried out in detail for axially symmetric oblate confocal ellipsoids, but possible generalizations are indicated. The Kerr metric is found to be an ellipsoidal space-time of this special kind. Some remarks concerning an (unfound) explicit interior Kerr solution conclude the paper
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 4. Giant Magnetoresistance - Nobel Prize in Physics 2007. Debakanta Samal P S Anil Kumar. General Article Volume 13 Issue 4 April 2008 pp 343-354. Fulltext. Click here to view fulltext PDF. Permanent link:
Geometric Invariant Measuring the Deviation from Kerr Data
Bäckdahl, Thomas; Kroon, Juan A. Valiente
2010-01-01
A geometrical invariant for regular asymptotically Euclidean data for the vacuum Einstein field equations is constructed. This invariant vanishes if and only if the data correspond to a slice of the Kerr black hole spacetime --thus, it provides a measure of the non-Kerr-like behavior of generic data. In order to proceed with the construction of the geometric invariant, we introduce the notion of approximate Killing spinors.
Geometric Invariant Measuring the Deviation from Kerr Data
Bäckdahl, Thomas; Valiente Kroon, Juan A.
2010-06-01
A geometrical invariant for regular asymptotically Euclidean data for the vacuum Einstein field equations is constructed. This invariant vanishes if and only if the data correspond to a slice of the Kerr black hole spacetime—thus, it provides a measure of the non-Kerr-like behavior of generic data. In order to proceed with the construction of the geometric invariant, we introduce the notion of approximate Killing spinors.
Nonlinear optics quantum computing with circuit QED.
Adhikari, Prabin; Hafezi, Mohammad; Taylor, J M
2013-02-08
One approach to quantum information processing is to use photons as quantum bits and rely on linear optical elements for most operations. However, some optical nonlinearity is necessary to enable universal quantum computing. Here, we suggest a circuit-QED approach to nonlinear optics quantum computing in the microwave regime, including a deterministic two-photon phase gate. Our specific example uses a hybrid quantum system comprising a LC resonator coupled to a superconducting flux qubit to implement a nonlinear coupling. Compared to the self-Kerr nonlinearity, we find that our approach has improved tolerance to noise in the qubit while maintaining fast operation.
Measurement of nonlinear refractive index and ionization rates in air using a wavefront sensor.
Schwarz, Jens; Rambo, Patrick; Kimmel, Mark; Atherton, Briggs
2012-04-09
A wavefront sensor has been used to measure the Kerr nonlinear focal shift of a high intensity ultrashort pulse beam in a focusing beam geometry while accounting for the effects of plasma-defocusing. It is shown that plasma-defocusing plays a major role in the nonlinear focusing dynamics and that measurements of Kerr nonlinearity and ionization are coupled. Furthermore, this coupled effect leads to a novel way that measures the laser ionization rates in air under atmospheric conditions as well as Kerr nonlinearity. The measured nonlinear index n₂ compares well with values found in the literature and the measured ionization rates could be successfully benchmarked to the model developed by Perelomov, Popov, and Terentev (PPT model) [Sov. Phys. JETP 50, 1393 (1966)].
Shadows of Kerr Black Holes with Scalar Hair.
Cunha, Pedro V P; Herdeiro, Carlos A R; Radu, Eugen; Rúnarsson, Helgi F
2015-11-20
Using backwards ray tracing, we study the shadows of Kerr black holes with scalar hair (KBHSH). KBHSH interpolate continuously between Kerr BHs and boson stars (BSs), so we start by investigating the lensing of light due to BSs. Moving from the weak to the strong gravity region, BSs-which by themselves have no shadows-are classified, according to the lensing produced, as (i) noncompact, which yield not multiple images, (ii) compact, which produce an increasing number of Einstein rings and multiple images of the whole celestial sphere, and (iii) ultracompact, which possess light rings, yielding an infinite number of images with (we conjecture) a self-similar structure. The shadows of KBHSH, for Kerr-like horizons and noncompact BS-like hair, are analogous to, but distinguishable from, those of comparable Kerr BHs. But for non-Kerr-like horizons and ultracompact BS-like hair, the shadows of KBHSH are drastically different: novel shapes arise, sizes are considerably smaller, and multiple shadows of a single BH become possible. Thus, KBHSH provide quantitatively and qualitatively new templates for ongoing (and future) very large baseline interferometry observations of BH shadows, such as those of the Event Horizon Telescope.
The Kerr-Tomimatsu-Sato family of spinning mass solutions
International Nuclear Information System (INIS)
Yamazaki, M.
1982-01-01
The closed form with an arbitrary positive integer distortion parameter delta of the Kerr-Tomimatsu-Sato family of spinning mass solutions, i.e., stationary axisymmetric, asymptotically flat exact solutions of Einstein's vacuum field equations Rsub(μγ) = 0 is presented. The generalization of the Kerr-Tomimatsu-Sato family of solutions to the case of the arbitrary positive non-integral distortion parameter delta is conjectured. Some analytic properties of the family of solutions are studied. It is shown that all ring singularities are of first order and all ergosurfaces are simple zeros of metric functions f. The charged Kerr-Tomimatsu-Sato family of solutions is also given in the closed form with an arbitrary positive integer distortion parameter delta. It is shown that the Christodoulou-Ruffini mass formula of the Kerr-Newman field or the delta = 1 member of the present family of solutions also holds true in the case of the charged Kerr-Tomimatsu-Sato family of solutions with an arbitary odd integer delta. (Auth.)
Equatorial circular orbits in the Kerr-de Sitter spacetimes
International Nuclear Information System (INIS)
Stuchlik, Zdenek; Slany, Petr
2004-01-01
Equatorial motion of test particles in Kerr-de Sitter spacetimes is considered. Circular orbits are determined, their properties are discussed for both black-hole and naked-singularity spacetimes, and their relevance for thin accretion disks is established. The circular orbits constitute two families that coalesce at the so-called static radius. The orientation of the motion along the circular orbits is, in accordance with case of asymptotically flat Kerr spacetimes, defined by relating the motion to the locally nonrotating frames. The minus-family orbits are all counterrotating, while the plus-family orbits are usually corotating relative to these frames. However, the plus-family orbits become counterrotating in the vicinity of the static radius in all Kerr-de Sitter spacetimes, and they become counterrotating in the vicinity of the ring singularity in Kerr-de Sitter naked-singularity spacetimes with a low enough rotational parameter. In such spacetimes, the efficiency of the conversion of the rest energy into heat energy in the geometrically thin plus-family accretion disks can reach extremely high values exceeding the efficiency of the annihilation process. The transformation of a Kerr-de Sitter naked singularity into an extreme black hole due to accretion in the thin disks is briefly discussed for both the plus-family and minus-family disks. It is shown that such a conversion leads to an abrupt instability of the innermost parts of the plus-family accretion disks that can have strong observational consequences
Gravitational collapse to a Kerr-Newman black hole
Nathanail, Antonios; Most, Elias R.; Rezzolla, Luciano
2017-07-01
We present the first systematic study of the gravitational collapse of rotating and magnetized neutron stars to charged and rotating (Kerr-Newman) black holes. In particular, we consider the collapse of magnetized and rotating neutron stars assuming that no pair-creation takes place and that the charge density in the magnetosphere is so low that the stellar exterior can be described as an electrovacuum. Under these assumptions, which are rather reasonable for a pulsar that has crossed the 'death line', we show that when the star is rotating, it acquires a net initial electrical charge, which is then trapped inside the apparent horizon of the newly formed back hole. We analyse a number of different quantities to validate that the black hole produced is indeed a Kerr-Newman one and show that, in the absence of rotation or magnetic field, the end result of the collapse is a Schwarzschild or Kerr black hole, respectively.
Dephasing and Kerr type interaction effects in circuit quantum electrodynamics
Ginossar, Eran; Girvin, Steven
2012-02-01
There has been recently a significant advance in obtaining high quality factor resonators in superconducting circuit architectures. The reduction of the resonator line width motivates us to consider subtle Kerr type interaction effects in small clusters of cavities and transmon type qubits. The Kerr interaction leads to entanglement of cavities, which in the transient regime is manifested in collapse-revival dynamics. For longer time scales, the interaction of the system with its environment becomes important and we discuss how the entangled states are modified. The signal of this steady-state Kerr interaction is a multi-photon port-to-port scattering process which can be observed in homodyne measurements or in a spectral analysis (correlations). We discuss the relevance of these effects to the challenge of building quantum memories.
Zero mass limit of Kerr spacetime is a wormhole
Gibbons, Gary W.; Volkov, Mikhail S.
2017-07-01
We show that, contrary to what is usually claimed in the literature, the zero mass limit of Kerr spacetime is not flat Minkowski space but a spacetime whose geometry is only locally flat. This limiting spacetime, as the Kerr spacetime itself, contains two asymptotic regions and hence cannot be topologically trivial. It also contains a curvature singularity, because the power-law singularity of the Weyl tensor vanishes in the limit but there remains a distributional contribution of the Ricci tensor. This spacetime can be interpreted as a wormhole sourced by a negative tension ring. We also extend the discussion to similarly interpret the zero mass limit of the Kerr-(anti-)de Sitter spacetime.
A comment on Kerr-CFT and Wald entropy
International Nuclear Information System (INIS)
Krishnan, Chethan; Kuperstein, Stanislav
2009-01-01
We point out that the entropies of black holes in general diffeomorphism invariant theories, computed using the Kerr-CFT correspondence and the Wald formula (as implemented in the entropy function formalism), need not always agree. A simple way to illustrate this is to consider Einstein-Gauss-Bonnet gravity in four dimensions, where the Gauss-Bonnet term is topological. This means that the central charge of Kerr-CFT computed in the Barnich-Brandt-Compere formalism remains the same as in Einstein gravity, while the entropy computed using the entropy function gives a universal correction proportional to the Gauss-Bonnet coupling. We argue that at least in this example, the Kerr-CFT result is the physically reasonable one. The resolution to this discrepancy might lie in a better understanding of boundary terms.
Destroying a near-extremal Kerr-Newman black hole
International Nuclear Information System (INIS)
Saa, Alberto; Santarelli, Raphael
2011-01-01
We revisit here a previous argument due to Wald showing the impossibility of turning an extremal Kerr-Newman black hole into a naked singularity by plunging test particles across the black hole event horizon. We extend Wald's analysis to the case of near-extremal black holes and show that it is indeed possible to destroy their event horizon, giving rise to naked singularities, by pushing test particles toward the black hole as, in fact, it has been demonstrated explicitly by several recent works. Our analysis allows us to go a step further and to determine the optimal values, in the sense of keeping to a minimum the backreaction effects, of the test particle electrical charge and angular momentum necessary to destroy a given near-extremal Kerr-Newman black hole. We describe briefly a possible realistic scenario for the creation of a Kerr naked singularity from some recently discovered candidates to be rapidly rotating black holes in radio galaxies.
Fendzi-Donfack, Emmanuel; Nguenang, Jean Pierre; Nana, Laurent
2018-02-01
We use the fractional complex transform with the modified Riemann-Liouville derivative operator to establish the exact and generalized solutions of two fractional partial differential equations. We determine the solutions of fractional nonlinear electrical transmission lines (NETL) and the perturbed nonlinear Schroedinger (NLS) equation with the Kerr law nonlinearity term. The solutions are obtained for the parameters in the range (0operator and we found the traditional solutions for the limiting case of α =1. We show that according to the modified Riemann-Liouville derivative, the solutions found can describe physical systems with memory effect, transient effects in electrical systems and nonlinear transmission lines, and other systems such as optical fiber.
El-Menoufi, Basem Kamal
2016-05-01
In the context of effective field theory, we consider quantum gravity with minimally coupled massless particles. Fixing the background geometry to be of the Kerr-Schild type, we fully determine the one-loop effective action of the theory whose finite non-local part is induced by the long-distance portion of quantum loops. This is accomplished using the non-local expansion of the heat kernel in addition to a non-linear completion technique through which the effective action is expanded in gravitational curvatures. Via Euclidean methods, we identify a logarithmic correction to the Bekenstein-Hawking entropy of Schwarzschild black hole. Using dimensional transmutation the result is shown to exhibit an interesting interplay between the UV and IR properties of quantum gravity.
Energy Technology Data Exchange (ETDEWEB)
El-Menoufi, Basem Kamal [Department of Physics, University of Massachusetts,Amherst, MA 01003 (United States)
2016-05-05
In the context of effective field theory, we consider quantum gravity with minimally coupled massless particles. Fixing the background geometry to be of the Kerr-Schild type, we fully determine the one-loop effective action of the theory whose finite non-local part is induced by the long-distance portion of quantum loops. This is accomplished using the non-local expansion of the heat kernel in addition to a non-linear completion technique through which the effective action is expanded in gravitational curvatures. Via Euclidean methods, we identify a logarithmic correction to the Bekenstein-Hawking entropy of Schwarzschild black hole. Using dimensional transmutation the result is shown to exhibit an interesting interplay between the UV and IR properties of quantum gravity.
Logarithmic corrections to black hole entropy from Kerr/CFT
Energy Technology Data Exchange (ETDEWEB)
Pathak, Abhishek [Center for the Fundamental Laws of Nature, Harvard University,Cambridge, MA 02138 (United States); Porfyriadis, Achilleas P. [Center for the Fundamental Laws of Nature, Harvard University,Cambridge, MA 02138 (United States); Department of Physics, UCSB,Santa Barbara, CA 93106 (United States); Strominger, Andrew [Center for the Fundamental Laws of Nature, Harvard University,Cambridge, MA 02138 (United States); Varela, Oscar [Center for the Fundamental Laws of Nature, Harvard University,Cambridge, MA 02138 (United States); Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut),Am Mühlenberg 1, D-14476 Potsdam (Germany); Department of Physics, Utah State University,Logan, UT 84322 (United States)
2017-04-14
It has been shown by A. Sen that logarithmic corrections to the black hole area-entropy law are entirely determined macroscopically from the massless particle spectrum. They therefore serve as powerful consistency checks on any proposed enumeration of quantum black hole microstates. Sen’s results include a macroscopic computation of the logarithmic corrections for a five-dimensional near extremal Kerr-Newman black hole. Here we compute these corrections microscopically using a stringy embedding of the Kerr/CFT correspondence and find perfect agreement.
Entropy of Kerr-de Sitter black hole
Li, Huai-Fan; Ma, Meng-Sen; Zhang, Li-Chun; Zhao, Ren
2017-07-01
Based on the consideration that the black hole horizon and the cosmological horizon of Kerr-de Sitter black hole are not independent of each other, we conjecture the total entropy of the system should have an extra term contributed from the correlations between the two horizons, except for the sum of the two horizon entropies. By employing globally effective first law and effective thermodynamic quantities, we obtain the corrected total entropy and find that the region of stable state for Kerr-de Sitter is related to the angular velocity parameter a, i.e., the region of stable state becomes bigger as the rotating parameters a is increases.
On the six-dimensional Kerr theorem and twistor equation
Energy Technology Data Exchange (ETDEWEB)
Carneiro da Cunha, Bruno [Universidade Federal de Pernambuco, Departamento de Fisica, Recife, Pernambuco (Brazil)
2014-04-15
The Kerr theorem is revisited as part of the twistor program in six dimensions. The relationship between pure spinors and integrable 3-planes is investigated. The real condition for Lorentzian spacetimes is seen to induce a projective property in the space of solutions, reminiscent of the quaternionic structure of the six-dimensional Lorentz group. The twistor equation (or Killing spinor equations generically) also has an interpretation as integrable null planes, and a family of Einstein spacetimes with this property are presented in the Kerr-Schild fashion. (orig.)
2010-04-16
... Drought Management Planning at the Kerr Hydroelectric Project, Flathead Lake, MT AGENCY: Bureau of Indian... Impact Statement (FEIS) for Drought Management Planning at the Kerr Hydroelectric Project, Flathead Lake... drought management planning at the Kerr Hydroelectric Project no sooner than 30 days following the...
DEFF Research Database (Denmark)
Da Ros, Francesco; Sackey, I.; Jazayerifar, M.
2015-01-01
Kerr nonlinearity compensation by optical phase conjugation is demonstrated in a WDM PDM 16-QAM system. Improved received signal quality is reported for both dispersion-compensated and dispersion-uncompensated transmission and a comparison with digital backpropagation is provided....
Symmetry analyzer for nondestructive Bell-state detection using weak nonlinearities
International Nuclear Information System (INIS)
Barrett, S.D.; Kok, Pieter; Spiller, T.P.; Nemoto, Kae; Beausoleil, R.G.; Munro, W.J.
2005-01-01
We describe a method to project photonic two-qubit states onto the symmetric and antisymmetric subspaces of their Hilbert space. This device utilizes an ancillary coherent state, together with a weak cross-Kerr nonlinearity, generated, for example, by electromagnetically induced transparency. The symmetry analyzer is nondestructive, and works for small values of the cross-Kerr coupling. Furthermore, this device can be used to construct a nondestructive Bell-state detector
Near-field thermal upconversion and energy transfer through a Kerr medium.
Khandekar, Chinmay; Rodriguez, Alejandro W
2017-09-18
We present an approach for achieving large Kerr χ (3) -mediated thermal energy transfer at the nanoscale that exploits a general coupled-mode description of triply resonant, four-wave mixing processes. We analyze the efficiency of thermal upconversion and energy transfer from mid- to near-infrared wavelengths in planar geometries involving two slabs supporting far-apart surface plasmon polaritons and separated by a nonlinear χ (3) medium that is irradiated by externally incident light. We study multiple geometric and material configurations and different classes of intervening mediums-either bulk or nanostructured lattices of nanoparticles embedded in nonlinear materials-designed to resonantly enhance the interaction of the incident light with thermal slab resonances. We find that even when the entire system is in thermodynamic equilibrium (at room temperature) and under typical drive intensities ~ W/μm 2 , the resulting upconversion rates can approach and even exceed thermal flux rates achieved in typical symmetric and non-equilibrium configurations of vacuum-separated slabs. The proposed nonlinear scheme could potentially be exploited to achieve thermal cooling and refrigeration at the nanoscale, and to actively control heat transfer between materials with dramatically different resonant responses.
An Ultra-Efficient Nonlinear Platform: AlGaAs-On-Insulator
DEFF Research Database (Denmark)
Pu, Minhao; Ottaviano, Luisa; Semenova, Elizaveta
]. Though tremendous technological work in those platforms have greatly improved device performances, the relatively low intrinsic material nonlinearities of those materials limit device performances concerning efficiency. Therefore, an integrated nonlinear platform that combines a high material...... ) and microring resonators with quality factors on the order of 105 [6]. The large effective nonlinearity of such platform enables efficient nonlinear processes such as high-speed optical signal processing [7], supercontinuum generation, and Kerr frequency comb generation [8]. Moreover, the required operation...
Collapse of Incoherent Light Beams in Inertial Bulk Kerr Media
DEFF Research Database (Denmark)
Bang, Ole; Edmundson, Darran; Królikowski, Wieslaw
1999-01-01
We use the coherent density function theory to show that partially coherent beams are unstable and may collapse in inertial bulk Kerr media. The threshold power for collapse, and its dependence on the degree of coherence, is found analytically and checked-numerically. The internal dynamics of the...
Particle creation in a rectilinear model of the Kerr metric
International Nuclear Information System (INIS)
Bilodeau, A.
1977-01-01
The neutrino field is studied in a rectilinear model of the Kerr metric. Superradiance is absent. A calculation is made of the energy flow, which leads to an interpretation of particle creation. The model chosen gives rise to a problem formally similar to the one encountered in the Klein paradox [fr
Ultrafast time-resolved spectroscopy of white-light continuum by optical Kerr grating
Wang, Yusu; Sui, Laizhi; Jiang, Yuanfei; Liu, Dunli; Li, Qingyi; Chen, Anmin; Jin, Mingxing
2017-05-01
We have optimized a femtosecond time-resolved system by the optical Kerr-gate (OKG) method to investigate characteristics of various Kerr media. Optical Kerr gating is widely used in ultrafast measurements ranging from pulse characterization to spectroscopy and microscopy. We compared the efficiencies and the temporal responses of three Kerr media CS2, benzene and GGG. We have demonstrated that benzene has fast response and low efficiency while CS2 has high efficiency and slow response. Benzene as a Kerr medium shows the most befitting characteristics in the three media.
Self-guiding light in layered nonlinear media
DEFF Research Database (Denmark)
Bergé, L.; Mezentsev, V. K.; Juul Rasmussen, Jens
2000-01-01
We study the propagation of intense optical beams in layered Kerr media. With appropriate shapes, beams with a power close to the self-focusing threshold are shown to propagate over long distances as quasistationary waveguides in cubic media supporting a periodic nonlinear refractive index. (C) 2...
Extremal characterization of band gaps in nonlinear gratings
van Groesen, Embrecht W.C.; Sopaheluwakan, A.
In this paper we present an explicit extremal characterization of the edges of the lowest band gap in gratings; we restrict here to the case of TE-modes, but the TM case can be treated similarly. The characterization is valid for linear and Kerr-nonlinear gratings, for smooth as well as for
Kanter, Rosabeth Moss
2008-01-01
Large corporations have long been seen as lumbering, inflexible, bureaucratic--and clueless about global developments. But recently some multinationals seem to be transforming themselves: They're engaging employees, moving quickly, and introducing innovations that show true connection with the world. Harvard Business School's Kanter ventured with a research team inside a dozen global giants--including IBM, Procter & Gamble, Omron, CEMEX, Cisco, and Banco Real--to discover what has been driving the change. After conducting more than 350 interviews on five continents, she and her colleagues came away with a strong sense that we are witnessing the dawn of a new model of corporate power: The coordination of actions and decisions on the front lines now appears to stem from widely shared values and a sturdy platform of common processes and technology, not from top-down decrees. In particular, the values that engage the passions of far-flung workforces stress openness, inclusion, and making the world a better place. Through this shift in what might be called their guidance systems, the companies have become as creative and nimble as much smaller ones, even while taking on social and environmental challenges of a scale that only large enterprises could attempt. IBM, for instance, has created a nonprofit partnership, World Community Grid, through which any organization or individual can donate unused computing power to research projects and see what is being done with the donation in real time. IBM has gained an inspiring showcase for its new technology, helped business partners connect with the company in a positive way, and offered individuals all over the globe the chance to contribute to something big.
Giant cell arteritis is a disorder that causes inflammation of your arteries, usually in the scalp, neck, and arms. ... arteries, which keeps blood from flowing well. Giant cell arteritis often occurs with another disorder called polymyalgia ...
... nevus; Giant hairy nevus; Giant pigmented nevus; Bathing trunk nevus; Congenital melanocytic nevus - large ... the spine) Involvement of the membranes of the brain and spinal cord when the nevus affects a ...
The Quantization of a Kerr-AdS Black Hole
Directory of Open Access Journals (Sweden)
Claus Gerhardt
2018-01-01
Full Text Available We apply our model of quantum gravity to a Kerr-AdS space-time of dimension 2m+1, m≥2, where all rotational parameters are equal, resulting in a wave equation in a quantum space-time which has a sequence of solutions that can be expressed as a product of stationary and temporal eigenfunctions. The stationary eigenfunctions can be interpreted as radiation and the temporal ones as gravitational waves. The event horizon corresponds in the quantum model to a Cauchy hypersurface that can be crossed by causal curves in both directions such that the information paradox does not occur. We also prove that the Kerr-AdS space-time can be maximally extended by replacing in a generalized Boyer-Lindquist coordinate system the r variable by ρ=r2 such that the extended space-time has a timelike curvature singularity in ρ=-a2.
Finite escape fraction for ultrahigh energy collisions around Kerr ...
Indian Academy of Sciences (India)
where. = r2 + a2 − 2r and a is the angular momentum parameter. When a > 1, event horizon is absent in the space-time. However, there is a singularity located at r = 0,θ = π/2, which turns out to be visible for the asymptotic observer. Thus, the Kerr solution represents a naked singularity. We now analyse the geodesic motion ...
Weakly charged generalized Kerr-NUT-(A)dS spacetimes
Frolov, Valeri P.; Krtouš, Pavel; Kubizňák, David
2017-08-01
We find an explicit solution of the source free Maxwell equations in a generalized Kerr-NUT-(A)dS spacetime in all dimensions. This solution is obtained as a linear combination of the closed conformal Killing-Yano tensor hab, which is present in such a spacetime, and a derivative of the primary Killing vector, associated with hab. For the vanishing cosmological constant the obtained solution reduces to the Wald's electromagnetic field generated from the primary Killing vector.
Vacuum energy in Kerr-AdS black holes
Olavarria, Gonzalo; Olea, Rodrigo
2014-01-01
We compute the vacuum energy for Kerr black holes with anti-de Sitter (AdS) asymptotics in dimensions 5≤D≤9 with all rotation parameters. The calculations are carried out employing an alternative regularization scheme for asymptotically AdS gravity, which considers supplementing the bulk action with counterterms which are a given polynomial in the extrinsic and intrinsic curvatures of the boundary (also known as Kounterterms). The Kerr-Schild form of the rotating solutions enables us to identify the vacuum energy as coming from the part of the metric that corresponds to a global AdS spacetime written in oblate spheroidal coordinates. We find that the zero-point energy for higher-dimensional Kerr-AdS reduces to one of a Schwarzschild-AdS black hole when all the rotation parameters are equal to each other, a fact that is well known in five dimensions. We also sketch a compact expression for the vacuum energy formula in terms of asymptotic quantities that might be useful to extend the computations to higher odd dimensions.
Quasinormal modes of Kerr-de Sitter black holes
International Nuclear Information System (INIS)
Yoshida, Shijun; Uchikata, Nami; Futamase, Toshifumi
2010-01-01
We calculate the fundamental quasinormal modes of the Kerr-de Sitter black hole for the first time. In order to calculate the quasinormal modes, we employ the master equations derived by Suzuki, Takasugi, and Umetsu, who transform the Teukolsky equations for the Kerr-de Sitter black hole into the standard form of the Heun's equation. The transformed functions are expanded around the outer horizon of the black hole or the symmetric axis in the Froebenius series whose coefficients satisfy a three-term recurrence relation. These three-term recurrence relations allow us to use Leaver's continued fraction method to calculate the angular separation constant and the quasinormal mode frequency. Any unstable fundamental quasinormal mode is not found in this paper. It is also observed that for some black holes characterized by a large mass parameter, some retrograde modes in the slow rotation limit become prograde as the black hole spin increases. This phenomenon does not occur for the fundamental modes of the Kerr black hole.
Valley-selective optical Stark effect probed by Kerr rotation
LaMountain, Trevor; Bergeron, Hadallia; Balla, Itamar; Stanev, Teodor K.; Hersam, Mark C.; Stern, Nathaniel P.
2018-01-01
The ability to monitor and control distinct states is at the heart of emerging quantum technologies. The valley pseudospin in transition metal dichalcogenide (TMDC) monolayers is a promising degree of freedom for such control, with the optical Stark effect allowing for valley-selective manipulation of energy levels in WS2 and WSe2 using ultrafast optical pulses. Despite these advances, understanding of valley-sensitive optical Stark shifts in TMDCs has been limited by reflectance-based detection methods where the signal is small and prone to background effects. More sensitive polarization-based spectroscopy is required to better probe ultrafast Stark shifts for all-optical manipulation of valley energy levels. Here, we show time-resolved Kerr rotation to be a more sensitive probe of the valley-selective optical Stark effect in monolayer TMDCs. Compared to the established time-resolved reflectance methods, Kerr rotation is less sensitive to background effects. Kerr rotation provides a fivefold improvement in the signal-to-noise ratio of the Stark effect optical signal and a more precise estimate of the energy shift. This increased sensitivity allows for observation of an optical Stark shift in monolayer MoS2 that exhibits both valley and energy selectivity, demonstrating the promise of this method for investigating this effect in other layered materials and heterostructures.
Gravitational redshift in Kerr-Newman geometry using gravity's rainbow
Dubey, Anuj Kumar; Sen, A. K.; Mazumdar, Bijoy
2017-11-01
Gravitational redshift is generally reported by most of the authors without considering the influence of the energy of the test particle using various spacetime geometries such as Schwarzschild, Reissner-Nordstrom, Kerr and Kerr-Newman geometries for static, charged static, rotating and charged rotating objects respectively. In the present work, the general expression for the energy dependent gravitational redshift is derived for charged rotating body using the Kerr-Newman geometry along with the energy dependent gravity's rainbow function. It is found that the gravitational redshift is influenced by the energy of the photon. One may obtain greater correction in the value of gravitational redshift, using the high energy photons. Knowing the value of gravitational redshift from a high energy sources such as Gamma-ray Bursters (GRB), one may obtain the idea of upper bounds on the dimensionless rainbow function parameter (ξ). Also there may be a possibility to introduce a new physical scale of the order of ξ/E_{Pl}.
Quasilocal thermodynamics of Kerr and Kerr--anti-de Sitter spacetimes and the AdS/CFT correspondence
International Nuclear Information System (INIS)
Dehghani, M. H.; Mann, R. B.
2001-01-01
We consider the quasilocal thermodynamics of rotating black holes in asymptotically flat and asymptotically anti--de Sitter (AdS) spacetimes. Using the minimal number of intrinsic boundary counterterms inspired by the AdS/conformal field theory correspondence, we find that we are able to carry out an analysis of the thermodynamics of these black holes for virtually all possible values of the rotation parameter and cosmological constant that leave the quasilocal boundary well defined, going well beyond what is possible with background subtraction methods. Specifically, we compute the quasilocal energy E and angular momentum J for arbitrary values of the rotation, mass, and cosmological constant parameters for the (3+1)-dimensional Kerr, Kerr-AdS black holes, and (2+1)-dimensional Banados-Teitelboim-Zannelli (BTZ) black hole. We perform a quasilocal stability analysis and find phase behavior that is commensurate with previous analyses carried out at infinity
DEFF Research Database (Denmark)
Kutluyarov, Ruslan V.; Bagmanov, Valeriy Kh; Antonov, Vyacheslav V.
2017-01-01
This paper is focused on the analysis of linear and nonlinear mode coupling in space division multiplexed (SDM) optical communications over step-index fiber in few-mode regime. Linear mode coupling is caused by the fiber imperfections, while the nonlinear coupling is caused by the Kerr-nonlineari......This paper is focused on the analysis of linear and nonlinear mode coupling in space division multiplexed (SDM) optical communications over step-index fiber in few-mode regime. Linear mode coupling is caused by the fiber imperfections, while the nonlinear coupling is caused by the Kerr...... to a significant increase of the nonlinear distortions. It is necessary to take this phenomenon into account in SDM systems with linear compensation of mode coupling, because the nonlinear distortions may sufficiently decrease the effectiveness of the compensation....
Energy Technology Data Exchange (ETDEWEB)
Solookinejad, G., E-mail: ghsolooki@gmail.com
2016-09-15
In this study, the linear and nonlinear susceptibility of a single-layer graphene nanostructure driven by a weak probe light and an elliptical polarized coupling field is discussed theoretically. The Landau levels of graphene can be separated in infrared or terahertz regions under the strong magnetic field. Therefore, by using the density matrix formalism in quantum optic, the linear and nonlinear susceptibility of the medium can be derived. It is demonstrated that by adjusting the elliptical parameter, one can manipulate the linear and nonlinear absorption as well as Kerr nonlinearity of the medium. It is realized that the enhanced Kerr nonlinearity can be possible with zero linear absorption and nonlinear amplification at some values of elliptical parameter. Our results may be having potential applications in quantum information science based on Nano scales devices.
International Nuclear Information System (INIS)
Torres-Torres, C; López-Suárez, A; Oliver, A; Can-Uc, B; Rangel-Rojo, R; Tamayo-Rivera, L
2015-01-01
The study of the third-order optical nonlinear response exhibited by a composite containing gold nanoparticles and silicon quantum dots nucleated by ion implantation in a high-purity silica matrix is presented. The nanocomposites were explored as an integrated configuration containing two different ion-implanted distributions. The time-resolved optical Kerr gate and z-scan techniques were conducted using 80 fs pulses at a 825 nm wavelength; while the nanosecond response was investigated by a vectorial two-wave mixing method at 532 nm with 1 ns pulses. An ultrafast purely electronic nonlinearity was associated to the optical Kerr effect for the femtosecond experiments, while a thermal effect was identified as the main mechanism responsible for the nonlinear optical refraction induced by nanosecond pulses. Comparative experimental tests for examining the contribution of the Au and Si distributions to the total third-order optical response were carried out. We consider that the additional defects generated by consecutive ion irradiations in the preparation of ion-implanted samples do not notably modify the off-resonance electronic optical nonlinearities; but they do result in an important change for near-resonant nanosecond third-order optical phenomena exhibited by the closely spaced nanoparticle distributions. (paper)
Derivation of an applied nonlinear Schroedinger equation
Energy Technology Data Exchange (ETDEWEB)
Pitts, Todd Alan [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Laine, Mark Richard [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Schwarz, Jens [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Rambo, Patrick K. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Karelitz, David B. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
2015-01-01
We derive from first principles a mathematical physics model useful for understanding nonlinear optical propagation (including filamentation). All assumptions necessary for the development are clearly explained. We include the Kerr effect, Raman scattering, and ionization (as well as linear and nonlinear shock, diffraction and dispersion). We explain the phenomenological sub-models and each assumption required to arrive at a complete and consistent theoretical description. The development includes the relationship between shock and ionization and demonstrates why inclusion of Drude model impedance effects alters the nature of the shock operator. Unclassified Unlimited Release
Schrodinger cat state generation using a slow light
International Nuclear Information System (INIS)
Ham, B. S.; Kim, M. S.
2003-01-01
We show a practical application of giant Kerr nonlinearity to quantum information processing based on superposition of two distinct macroscopic states- Schrodinger cat state. The giant Kerr nonlinearity can be achieved by using electromagnetically induced transparency, in which light propagation should be slowed down so that a pi-phase shift can be easily obtained owing to increased interaction time.
Multi-bi- and tri-stability using nonlinear plasmonic Fano resonators
Amin, Muhammad
2013-09-01
A plasmonic Fano resonator embedding Kerr nonlinearity is used to achieve multi-bi- and tri-stability. Fano resonance is obtained by inducing higher-order plasmon modes on metallic surfaces via geometrical symmetry breaking. The presence of the multiple higher order plasmon modes provides the means for producing multi-bi- or tri-stability in the response of the resonator when it is loaded with a material with Kerr nonlinearity. The multi-stability in the response of the proposed resonator enables its use in three-state all optical memory and switching applications. © 2013 IEEE.
Constraints on two accretion disks centered on the equatorial plane of a Kerr SMBH
Pugliese, Daniela; Stuchlík, Zdeněk
2017-12-01
The possibility that two toroidal accretion configurations may be orbiting around a super–massive Kerr black hole has been addressed. Such tori may be formed during different stages of the Kerr attractor accretion history. We consider the relative rotation of the tori and the corotation or counterrotation of a single torus with respect to the Kerr attractor. We give classification of the couples of accreting and non–accreting tori in dependence on the Kerr black hole dimensionless spin. We demonstrate that only in few cases a double accretion tori system may be formed under specific conditions.
Kerr Non-linerity in Slow Light Propagation for Quantum Teleportation
Tombesi, Paolo
2001-05-01
Quantum teleportation(C.H. Bennett et al)., Phys. Rev. Lett. 70, 1895 (1993). is the ``reconstruction" with 100% success, of an unknown state given to one station (Alice), performed at another remote station (Bob), on the basis of two bits of classical information sent by Alice to Bob. Perfect teleportation is possible only if the two parties share a maximally entangled state. The most delicate part needed for the effective realization of teleportation is the Bell-state measurement, i.e. the discrimination between the four, maximally entangled, Bell states which has to be performed by Alice and whose result is communicated to Bob through the classical channel. There have been numerous proposals for its realization in different systems and recently beautiful, pioneering experiments have provided convincing experimental proof-of-principle of the correctness of the teleportation concept. These experiments differ by the degrees of freedom used as qubits and for the different ways in which the Bell-state measurement is performed. The Innsbruck experiment (D.Bouwmeester et al)., Nature (London) 390, 575 (1997). is the conceptually simplest one, since each qubit is represented by the polarization state of a single photon pulse. In this experiment, however, only two out of the four Bell states can be discriminated and therefore the success rate cannot be larger than 50%. It is therefore desirable to have a scheme for a Bell-state measurement that can be used in the simplest case of the Innsbruck experiment. This would imply the possibility of realizing the first complete verification of the original quantum teleportation scheme(C.H. Bennett et al)., Phys. Rev. Lett. 70, 1895 (1993). and also of having a device useful for other quantum protocols, as quantum dense coding. A scheme for perfect Bell-state discrimination based on a non-linear optical effect, the cross-phase modulation taking place in Kerr media, will be discussed. We shall show that the needed crossed-Kerr non-linearity
Off-diagonal deformations of Kerr metrics and black ellipsoids in heterotic supergravity
International Nuclear Information System (INIS)
Vacaru, Sergiu I.; Irwin, Klee
2017-01-01
Geometric methods for constructing exact solutions of equations of motion with first order α ' corrections to the heterotic supergravity action implying a nontrivial Yang-Mills sector and six-dimensional, 6-d, almost-Kaehler internal spaces are studied. In 10-d spacetimes, general parametrizations for generic off-diagonal metrics, nonlinear and linear connections, and matter sources, when the equations of motion decouple in very general forms are considered. This allows us to construct a variety of exact solutions when the coefficients of fundamental geometric/physical objects depend on all higher-dimensional spacetime coordinates via corresponding classes of generating and integration functions, generalized effective sources and integration constants. Such generalized solutions are determined by generic off-diagonal metrics and nonlinear and/or linear connections; in particular, as configurations which are warped/compactified to lower dimensions and for Levi-Civita connections. The corresponding metrics can have (non-) Killing and/or Lie algebra symmetries and/or describe (1+2)-d and/or (1+3)-d domain wall configurations, with possible warping nearly almost-Kaehler manifolds, with gravitational and gauge instantons for nonlinear vacuum configurations and effective polarizations of cosmological and interaction constants encoding string gravity effects. A series of examples of exact solutions describing generic off-diagonal supergravity modifications to black hole/ellipsoid and solitonic configurations are provided and analyzed. We prove that it is possible to reproduce the Kerr and other type black solutions in general relativity (with certain types of string corrections) in the 4-d case and to generalize the solutions to non-vacuum configurations in (super-) gravity/string theories. (orig.)
Off-diagonal deformations of Kerr metrics and black ellipsoids in heterotic supergravity
Energy Technology Data Exchange (ETDEWEB)
Vacaru, Sergiu I. [Quantum Gravity Research, Topanga, CA (United States); University ' ' Al. I. Cuza' ' , Project IDEI, Iasi (Romania); Irwin, Klee [Quantum Gravity Research, Topanga, CA (United States)
2017-01-15
Geometric methods for constructing exact solutions of equations of motion with first order α{sup '} corrections to the heterotic supergravity action implying a nontrivial Yang-Mills sector and six-dimensional, 6-d, almost-Kaehler internal spaces are studied. In 10-d spacetimes, general parametrizations for generic off-diagonal metrics, nonlinear and linear connections, and matter sources, when the equations of motion decouple in very general forms are considered. This allows us to construct a variety of exact solutions when the coefficients of fundamental geometric/physical objects depend on all higher-dimensional spacetime coordinates via corresponding classes of generating and integration functions, generalized effective sources and integration constants. Such generalized solutions are determined by generic off-diagonal metrics and nonlinear and/or linear connections; in particular, as configurations which are warped/compactified to lower dimensions and for Levi-Civita connections. The corresponding metrics can have (non-) Killing and/or Lie algebra symmetries and/or describe (1+2)-d and/or (1+3)-d domain wall configurations, with possible warping nearly almost-Kaehler manifolds, with gravitational and gauge instantons for nonlinear vacuum configurations and effective polarizations of cosmological and interaction constants encoding string gravity effects. A series of examples of exact solutions describing generic off-diagonal supergravity modifications to black hole/ellipsoid and solitonic configurations are provided and analyzed. We prove that it is possible to reproduce the Kerr and other type black solutions in general relativity (with certain types of string corrections) in the 4-d case and to generalize the solutions to non-vacuum configurations in (super-) gravity/string theories. (orig.)
Rigorous theory of molecular orientational nonlinear optics
Directory of Open Access Journals (Sweden)
Chong Hoon Kwak
2015-01-01
Full Text Available Classical statistical mechanics of the molecular optics theory proposed by Buckingham [A. D. Buckingham and J. A. Pople, Proc. Phys. Soc. A 68, 905 (1955] has been extended to describe the field induced molecular orientational polarization effects on nonlinear optics. In this paper, we present the generalized molecular orientational nonlinear optical processes (MONLO through the calculation of the classical orientational averaging using the Boltzmann type time-averaged orientational interaction energy in the randomly oriented molecular system under the influence of applied electric fields. The focal points of the calculation are (1 the derivation of rigorous tensorial components of the effective molecular hyperpolarizabilities, (2 the molecular orientational polarizations and the electronic polarizations including the well-known third-order dc polarization, dc electric field induced Kerr effect (dc Kerr effect, optical Kerr effect (OKE, dc electric field induced second harmonic generation (EFISH, degenerate four wave mixing (DFWM and third harmonic generation (THG. We also present some of the new predictive MONLO processes. For second-order MONLO, second-order optical rectification (SOR, Pockels effect and difference frequency generation (DFG are described in terms of the anisotropic coefficients of first hyperpolarizability. And, for third-order MONLO, third-order optical rectification (TOR, dc electric field induced difference frequency generation (EFIDFG and pump-probe transmission are presented.
Spherical null geodesics of rotating Kerr black holes
International Nuclear Information System (INIS)
Hod, Shahar
2013-01-01
The non-equatorial spherical null geodesics of rotating Kerr black holes are studied analytically. Unlike the extensively studied equatorial circular orbits whose radii are known analytically, no closed-form formula exists in the literature for the radii of generic (non-equatorial) spherical geodesics. We provide here an approximate formula for the radii r ph (a/M;cosi) of these spherical null geodesics, where a/M is the dimensionless angular momentum of the black hole and cos i is an effective inclination angle (with respect to the black-hole equatorial plane) of the orbit. It is well-known that the equatorial circular geodesics of the Kerr spacetime (the prograde and the retrograde orbits with cosi=±1) are characterized by a monotonic dependence of their radii r ph (a/M;cosi=±1) on the dimensionless spin-parameter a/M of the black hole. We use here our novel analytical formula to reveal that this well-known property of the equatorial circular geodesics is actually not a generic property of the Kerr spacetime. In particular, we find that counter-rotating spherical null orbits in the range (3√(3)−√(59))/4≲cosi ph (a/M;cosi=const) on the dimensionless rotation-parameter a/M of the black hole. Furthermore, it is shown that spherical photon orbits of rapidly-rotating black holes are characterized by a critical inclination angle, cosi=√(4/7), above which the coordinate radii of the orbits approach the black-hole radius in the extremal limit. We prove that this critical inclination angle signals a transition in the physical properties of the spherical null geodesics: in particular, it separates orbits which are characterized by finite proper distances to the black-hole horizon from orbits which are characterized by infinite proper distances to the horizon.
Corotating two-body system of identical Kerr sources
Directory of Open Access Journals (Sweden)
I. Cabrera-Munguia
2017-09-01
Full Text Available A binary system of equal corotating Kerr sources is studied after deriving the corresponding 3-parametric asymptotically flat exact solution. Both sources are apart from each other by means of a massless strut (conical singularity. In the context of black holes, the analytical functional form of each horizon σ is expressed in terms of arbitrary Komar physical parameters: mass M, angular momentum J (with parallel spin, and the coordinate distance R. Later on, all the thermodynamical properties related to the horizon are depicted by concise formulae. Finally, the extreme limit case is obtained as a 2-parametric subclass of Kinnersley–Chitre metric.
Distributional energy--momentum tensor of the Kerr--Newman spacetime family
Balasin, Herbert; Nachbagauer, Herbert
1994-06-01
Using the Kerr-Schild decomposition of the metric tensor that employs the algebraically special nature of the Kerr-Newman space-time family, we calculate the energy-momentum tensor. The latter turns out to be a well-defined tensor-distribution with disk-like support.
Managing the research university : Clark Kerr and the University of California
Soo, M; Carson, C
In the 1950s and 1960s, Clark Kerr led the University of California's Berkeley campus, and then the University of California as a whole. Throughout these years, he developed a system of managerial strategies. This paper shows how Kerr's administrative views drew upon his background in industrial
Massive-spin-1/2 wave around a Kerr-Newman black hole
International Nuclear Information System (INIS)
Lee, C.H.
1977-01-01
Using the separation of variables of the Dirac equations for the electron in the Kerr-Newman geometry, it is explicitly shown that the super-radiant scattering is not allowed for the electron wave on a Kerr-Newman black hole
Effects of resonator input power on Kerr lens mode-locked lasers
Indian Academy of Sciences (India)
Abstract. Using the ABCD matrix method, the common stability region between the sagittal and tangential planes of a four-mirror Kerr lens mode-locked (KLM) laser cavity is obtained for different ranges of input power. In addition, the effect of the input power on the Kerr lens sensitivity is investigated. Optimal input power and ...
Proposal for electro-optic multiplier based on dual transverse electro-optic Kerr effect.
Li, Changsheng
2008-10-20
A novel electro-optic multiplier is proposed, which can perform voltage multiplication operation by use of the Kerr medium exhibiting dual transverse electro-optic Kerr effect. In this kind of Kerr medium, electro-optic phase retardation is proportional to the square of its applied electric field, and orientations of the field-induced birefringent axes are only related to the direction of the field. Based on this effect, we can design an electro-optic multiplier by selecting the crystals of 6/mmm, 432, and m3m classes and isotropic Kerr media such as glass. Simple calculation demonstrates that a kind of glass-ceramic material with a large Kerr constant can be used for the design of the proposed electro-optic multiplier.
Boundary conditions for Kerr-AdS perturbations
Dias, Óscar J. C.; Santos, Jorge E.
2013-10-01
The Teukolsky master equation and its associated spin-weighted spheroidal harmonic decomposition simplify considerably the study of linear gravitational perturbations of the Kerr(-AdS) black hole. However, the formulation of the problem is not complete before we assign the physically relevant boundary conditions. We find a set of two Robin boundary conditions (BCs) that must be imposed on the Teukolsky master variables to get perturbations that are asymptotically global AdS, i.e. that asymptotes to the Einstein Static Universe. In the context of the AdS/CFT correspondence, these BCs allow a non-zero expectation value for the CFT stress-energy tensor while keeping fixed the boundary metric. When the rotation vanishes, we also find the gauge invariant differential map between the Teukolsky and the Kodama-Ishisbashi (Regge-Wheeler-Zerilli) formalisms. One of our Robin BCs maps to the scalar sector and the other to the vector sector of the Kodama-Ishisbashi decomposition. The Robin BCs on the Teukolsky variables will allow for a quantitative study of instability timescales and quasinormal mode spectrum of the Kerr-AdS black hole. As a warm-up for this programme, we use the Teukolsky formalism to recover the quasinormal mode spectrum of global AdS-Schwarzschild, complementing previous analysis in the literature.
A Zeroth Law Compatible Model to Kerr Black Hole Thermodynamics
Directory of Open Access Journals (Sweden)
Viktor G. Czinner
2017-02-01
Full Text Available We consider the thermodynamic and stability problem of Kerr black holes arising from the nonextensive/nonadditive nature of the Bekenstein–Hawking entropy formula. Nonadditive thermodynamics is often criticized by asserting that the zeroth law cannot be compatible with nonadditive composition rules, so in this work we follow the so-called formal logarithm method to derive an additive entropy function for Kerr black holes also satisfying the zeroth law’s requirement. Starting from the most general, equilibrium compatible, nonadditive entropy composition rule of Abe, we consider the simplest non-parametric approach that is generated by the explicit nonadditive form of the Bekenstein–Hawking formula. This analysis extends our previous results on the Schwarzschild case, and shows that the zeroth law-compatible temperature function in the model is independent of the mass–energy parameter of the black hole. By applying the Poincaré turning point method, we also study the thermodynamic stability problem in the system.
The Kerr-Schild double copy in curved spacetime
Bahjat-Abbas, Nadia; Luna, Andrés; White, Chris D.
2017-12-01
The double copy is a much-studied relationship between scattering amplitudes in gauge and gravity theories, that has subsequently been extended to classical field solutions. In nearly all previous examples, the graviton field is defined around Minkowski space. Recently, it has been suggested that one may set up a double copy for gravitons defined around a non-trivial background. We investigate this idea from the point of view of the classical double copy. First, we use Kerr-Schild spacetimes to construct graviton solutions in curved space, as double copies of gauge fields on non-zero gauge backgrounds. Next, we find that we can reinterpret such cases in terms of a graviton on a non-Minkowski background, whose single copy is a gauge field in the same background spacetime. The latter type of double copy persists even when the background is not of Kerr-Schild form, and we provide examples involving conformally flat metrics. Our results will be useful in extending the remit of the double copy, including to possible cosmological applications.
Cosmic censorship conjecture in Kerr-Sen black hole
Gwak, Bogeun
2017-06-01
The validity of the cosmic censorship conjecture for the Kerr-Sen black hole, which is a solution to the low-energy effective field theory for four-dimensional heterotic string theory, is investigated using charged particle absorption. When the black hole absorbs the particle, the charge on it changes owing to the conserved quantities of the particle. Changes in the black hole are constrained to the equation for the motion of the particle and are consistent with the laws of thermodynamics. Particle absorption increases the mass of the Kerr-Sen black hole to more than that of the absorbed charges such as angular momentum and electric charge; hence, the black hole cannot be overcharged. In the near-extremal black hole, we observe a violation of the cosmic censorship conjecture for the angular momentum in the first order of expansion and the electric charge in the second order. However, considering an adiabatic process carrying the conserved quantities as those of the black hole, we prove the stability of the black hole horizon. Thus, we resolve the violation. This is consistent with the third law of thermodynamics.
Faraday and Kerr Effects Diagnostics for Underwater Exploding Wires
Sarkisov, G. S.; Fedotov-Gefen, A. V.; Krasik, Ya. E.
2012-10-01
Two-channel laser polarimeter was used to measure magnetic and electric fields in vicinity of underwater exploding wire. Nd:YAG Q-switch laser with 532nm wavelength, 100mJ energy and 5ns pulse width was used for probing. Single wire, parallel wires and X and V- shaped wires was used in experiments. Electric and magnetic field induced birefringes in the water results in changing of polarization stage of probing beam after propagation through this anisotropic medium. Magnetic field results in circular anisotropy of the water, while electric field creates linear anisotropy. Magnetic field results in rotation of polarization plan of linear-polarized probing beam. Electric field effect is more complicated- polarization plan of the laser beam subjected to pulsation and changing of ellipticity. Effect of electric field depends on initial probing geometry- angle between electrical field vector E and polarization plane of probing wave. In our exploding wire experiments we found influence of both Faraday and Kerr effects. It was demonstrated existence of Kerr effect inside bubbles at high voltage electrode. Effect of magnetic fields interaction for multi-wire loads was observed.
The Kerr/CFT correspondence and its extensions.
Compère, Geoffrey
2017-01-01
We present a first-principles derivation of the main results of the Kerr/CFT correspondence and its extensions using only tools from gravity and quantum field theory. Firstly, we review properties of extremal black holes with in particular the construction of an asymptotic Virasoro symmetry in the near-horizon limit. The entropy of extremal spinning or charged black holes is shown to match with a chiral half of Cardy's formula. Secondly, we show how a thermal 2-dimensional conformal field theory (CFT) is relevant to reproduce the dynamics of near-superradiant probes around near-extremal black holes in the semi-classical limit. Thirdly, we review the hidden conformal symmetries of asymptotically-flat black holes away from extremality and present how the non-extremal entropy can be matched with Cardy's formula. We follow an effective field theory approach and consider the Kerr-Newman black hole and its generalizations in various supergravity theories. The interpretation of these results by deformed dual conformal field theories is discussed and contrasted with properties of standard 2-dimensional CFTs. We conclude with a list of open problems.
The Kerr/CFT Correspondence and its Extensions
Directory of Open Access Journals (Sweden)
Geoffrey Compère
2012-10-01
Full Text Available We present a first-principles derivation of the main results of the Kerr/CFT correspondence and its extensions using only tools from gravity and quantum field theory, filling a few gaps in the literature when necessary. Firstly, we review properties of extremal black holes that imply, according to semi-classical quantization rules, that their near-horizon quantum states form a centrally-extended representation of the one-dimensional conformal group. This motivates the conjecture that the extremal Kerr and Reissner–Nordström black holes are dual to the chiral limit of a two-dimensional CFT. We also motivate the existence of an SL (2,ℤ family of two-dimensional CFTs, which describe in their chiral limit the extremal Kerr–Newman black hole. We present generalizations in anti-de Sitter spacetime and discuss other matter-coupling and higher-derivative corrections. Secondly, we show how a near-chiral limit of these CFTs reproduces the dynamics of near-superradiant probes around near-extremal black holes in the semi-classical limit. Thirdly, we review how the hidden conformal symmetries of asymptotically-flat black holes away from extremality, combined with their properties at extremality, allow for a microscopic accounting of the entropy of non-extremal asymptotically-flat rotating or charged black holes. We conclude with a list of open problems.
Direct imaging rapidly-rotating non-Kerr black holes
Energy Technology Data Exchange (ETDEWEB)
Bambi, Cosimo, E-mail: Cosimo.Bambi@physik.uni-muenchen.de [Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universitaet Muenchen, 80333 Munich (Germany); Caravelli, Francesco, E-mail: fcaravelli@perimeterinstitute.ca [Max Planck Institute for Gravitational Physics, Albert Einstein Institute, 14476 Golm (Germany); Department of Physics, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada); Modesto, Leonardo, E-mail: lmodesto@perimeterinstitute.ca [Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada)
2012-05-01
Recently, two of us have argued that non-Kerr black holes in gravity theories different from General Relativity may have a topologically non-trivial event horizon. More precisely, the spatial topology of the horizon of non-rotating and slow-rotating objects would be a 2-sphere, like in Kerr space-time, while it would change above a critical value of the spin parameter. When the topology of the horizon changes, the black hole central singularity shows up. The accretion process from a thin disk can potentially overspin these black holes and induce the topology transition, violating the Weak Cosmic Censorship Conjecture. If the astrophysical black hole candidates are not the black holes predicted by General Relativity, we might have the quite unique opportunity to see their central region, where classical physics breaks down and quantum gravity effects should appear. Even if the quantum gravity region turned out to be extremely small, at the level of the Planck scale, the size of its apparent image would be finite and potentially observable with future facilities.
Energy Technology Data Exchange (ETDEWEB)
Lopez-Suarez, A; Benami, A; Tamayo-Rivera L; Reyes-Esqueda, J A; Cheang-Wong, J C; Rodriguez-Fernandez, L; Crespo-Sosa, A; Oliver, A [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, D. F. 04510 (Mexico); R Rangel-Rojo [Departamento de Optica, Centro de Investigacion CientIfica y de Educacion Superior de Ensenada, Apartado Postal 2732, Ensenada, BC 22860 (Mexico); Torres-Torres, C, E-mail: rrangel@cicese.mx [Seccion de Estudios de Posgrado e Investigacion, ESIME-Z, Instituto Politecnico Nacional, D.F. 07738 (Mexico)
2011-01-01
We present nonlinear refractive results for three different systems produced by ion implantation: high purity silica substrates with silicon quantum dots (Si-QDs), silver nanoparticles (Ag-NPs), and one sample containing both. We used a femtosecond optical Kerr gate (OKG) with 80 fs pulses at 830 nm to investigate the magnitude and response time of their nonlinear response. The Ag-NPs samples were prepared implanting 2 MeV Ag{sup 2+} ions at different fluencies. A sample with 1x10{sup 17} ions/cm{sup 2} showed no discernible Kerr signal, while for one with 2.4x10{sup 17} ions/cm{sup 2} we measured |{chi}{sup (3)}|{sub 1111} = 5.1x10{sup -11} esu. The Si-QDs sample required irradiation with 1.5 MeV Si{sup 2+} ions, at a 2.5x10{sup 17} ions/cm{sup 2} fluence in order that the OKG results for this sample yielded a similar |{chi}{sup (3)}|{sub 1111} value. The sample containing the Si-QDs was then irradiated by 1 MeV Ag2+ ions at a 4.44 x 10{sup 16} ions/cm{sup 2} fluence and thermally treated, for which afterward we measured |{chi}{sup (3)}|{sub 1111} 1.7x10{sup -10} esu. In all cases the response time was quasi-instantaneous. These results imply that the inclusion of Ag-NPs at low fluence, enhances the nonlinearity of the composite by a factor of around three, and that this is purely electronic in nature. Pump-probe results show that there is not any nonlinear absorption present. We estimate that the confinement effect of the Si-QDs in the sample plays an important role for the excitation of the Surface Plasmon Resonance (SPR) related to the Ag-NPs. A theoretical model that describes the modification of the third order nonlinearity is also presented.
Nanodielectrics with giant permittivity
Indian Academy of Sciences (India)
Following the prediction, during the last couple of years we have investigated the effect of giant permittivity in one-dimensional systems of conventional metals and conjugated polymer chains. In this article, we have tried to summarize the works on giant permittivity and finally the fabrication of nanocapacitor using metal ...
Non-linear propagation of laser beam and focusing due to self ...
Indian Academy of Sciences (India)
... self-focusing analysis indicates that the Kerr non-linearity acts as a perturbation on the radial inhomogeneity due to ﬁber geometry. Analysis indicates that the paraxial rays and peripheral rays focus at different points, indicating aberration effect. Calculated critical power matches with the experimentally reported result.
Self-Similar Nanocavity Design with Ultrasmall Mode Volume for Single-Photon Nonlinearities
DEFF Research Database (Denmark)
Choi, Hyeongrak; Heuck, Mikkel; Englund, Dirk R.
2017-01-01
illustrate the design concept with a silicon-air one-dimensional photon crystal cavity that reaches an ultrasmall mode volume of V-eff similar to 7.01 x 10(-5)lambda(3) at lambda similar to 1550 nm. We show that the extreme light concentration in our design can enable ultrastrong Kerr nonlinearities, even...
Entanglement of a nonlinear two two-level atoms interacting with ...
Indian Academy of Sciences (India)
S Abdel-Khalek
2017-12-08
Dec 8, 2017 ... Abstract. In this paper we investigate the entanglement dynamics between two two-level atoms interacting with two coherent fields in two spatially separated cavities which are filled with a Kerr-like medium. We examine the effect of nonlinear medium on the dynamical properties of entanglement and atomic ...
Nonlinear terahertz coherent excitation of vibrational modes of liquids.
Allodi, Marco A; Finneran, Ian A; Blake, Geoffrey A
2015-12-21
We report the first coherent excitation of intramolecular vibrational modes via the nonlinear interaction of a TeraHertz (THz) light field with molecular liquids. A terahertz-terahertz-Raman pulse sequence prepares the coherences with a broadband, high-energy, (sub)picosecond terahertz pulse, that are then measured in a terahertz Kerr effect spectrometer via phase-sensitive, heterodyne detection with an optical pulse. The spectrometer reported here has broader terahertz frequency coverage, and an increased sensitivity relative to previously reported terahertz Kerr effect experiments. Vibrational coherences are observed in liquid diiodomethane at 3.66 THz (122 cm(-1)), and in carbon tetrachloride at 6.50 THz (217 cm(-1)), in exact agreement with literature values of those intramolecular modes. This work opens the door to 2D spectroscopies, nonlinear in terahertz field, that can study the dynamics of condensed-phase molecular systems, as well as coherent control at terahertz frequencies.
Directory of Open Access Journals (Sweden)
Chong Li
2017-02-01
Full Text Available We propose a scheme of unidirectional transmission in a 1D nonlinear topological photonic crystal based on the topological edge state and three order optical nonlinearity. The 1D photonic crystals consists of a nonlinear photonic crystal L and a linear photonic crystal R. In the backward direction, light is totally reflected for the photons transmission prohibited by the bandgap. While in the forward direction, light interacts with the nonlinear photonic crystal L by optical Kerr effect, bringing a topological phase reversal and results the topological edge mode arising at the interface which could transmit photons through the bandgaps both of the photonic crystal L and R. When the signal power intensity larger than a moderate low threshold value of 10.0 MW/cm2, the transmission contrast ratio could remain at 30 steadily.
Is the Kerr black hole a super accelerator?
Krasnikov, S.; Skvortsova, M. V.
2018-02-01
A number of long-standing puzzles, such as the origin of extreme-energy cosmic rays, could perhaps be solved if we found a mechanism for effectively transferring energy from black holes to particles and, correspondingly, accelerating the latter to (unboundedly, as long as we neglect the back reaction) large velocities. As of today the only such candidate mechanism in the case of the nonextreme Kerr black hole is colliding a particle that freely falls from infinity with a particle whose trajectory is subject to some special requirements to fulfil which it has to be suitably corrected by auxiliary collisions. In the present paper we prove that—at least when the relevant particles move in the equatorial plane and experience a single correcting collision—this mechanism does not work too. The energy of the final collision becomes unboundedly high only when the energies of the incoming particles do.
Particle dynamics near Kerr-MOG black hole
Energy Technology Data Exchange (ETDEWEB)
Sharif, M.; Shahzadi, Misbah [University of the Punjab, Department of Mathematics, Lahore (Pakistan)
2017-06-15
This paper explores the dynamics of both neutral and charged particles orbiting near a rotating black hole in scalar-tensor-vector gravity. We study the conditions for the particle to escape at the innermost stable circular orbit. We investigate the stability of orbits through the effective potential and Lyapunov exponent in the presence of a magnetic field. The effective force acting on particle is also discussed. We also study the center of mass energy of particle collision near the horizon of this black hole. Finally, we compare our results with the particle motion around Schwarzschild, Kerr and Schwarzschild-MOG black holes. It is concluded that the external magnetic field, spin parameter and dimensionless parameter of the theory have strong effects on the particle dynamics in modified gravity. (orig.)
Hawking Radiations from an Arbitrarily Accelerating Kerr Black Hole ...
Indian Academy of Sciences (India)
dimension is correct. 2. Hawking effect. The line element of an arbitrarily accelerating Kerr black hole (Jing et al. 1992) is ds2 = −(1 − C)dv2 + 2dvdr − 2fρ2dvdθ − 2 sin2 θ(CA + ρ2g)dvdϕ. − 2A sin2 θdrdϕ + ρ2dθ2 + 2Afρ2 sin2 θdθdϕ. + sin2 θ[(A2C + 2gAρ2) sin. 2 θ + A2 + r2]dϕ2,. (1) where f = −a sin θ + b sin ϕ + c cos ϕ, ...
On the Kerr-AdS/CFT correspondence
Amado, Julián Barragán; da Cunha, Bruno Carneiro; Pallante, Elisabetta
2017-08-01
We review the relation between four-dimensional global conformal blocks and field propagation in AdS5. Following the standard argument that marginal perturbations should backreact in the geometry, we turn to the study of scalar fields in the generic Kerr-AdS5 geometry. On one hand, the result for scattering coefficients can be obtained exactly using the isomonodromy technique, giving exact expressions in terms of c = 1 chiral conformal blocks. On the other hand, one can use the analogy between the scalar field equations to the Level 2 null field Ward identity in two dimensional Liouville field theory to write approximate expressions for the same coefficients in terms of semi-classical chiral Liouville conformal blocks. Surprisingly, the conformal block thus constructed has a well-behaved interpretation in terms of Liouville vertex operators.
Particle dynamics near Kerr-MOG black hole
Sharif, M.; Shahzadi, Misbah
2017-06-01
This paper explores the dynamics of both neutral and charged particles orbiting near a rotating black hole in scalar-tensor-vector gravity. We study the conditions for the particle to escape at the innermost stable circular orbit. We investigate the stability of orbits through the effective potential and Lyapunov exponent in the presence of a magnetic field. The effective force acting on particle is also discussed. We also study the center of mass energy of particle collision near the horizon of this black hole. Finally, we compare our results with the particle motion around Schwarzschild, Kerr and Schwarzschild-MOG black holes. It is concluded that the external magnetic field, spin parameter and dimensionless parameter of the theory have strong effects on the particle dynamics in modified gravity.
Transverse magnetization and giant magnetoimpedance in amorphous ribbons
International Nuclear Information System (INIS)
Orue, I.; Garcia-Arribas, A.; Saad, A.; Cos, D. de; Barandiaran, J.M.
2005-01-01
In the classical approach giant magnetoimpedance (GMI) is driven by the transverse permeability of the sample, as excited by the current flowing through it. Transverse permeability is usually taken as a constant, while detailed magnetization processes are important for the interpretation of GMI data. In most cases the transverse permeability (or magnetization) is only guessed by looking at the longitudinal magnetization curve and direct determinations of such parameter are scarce in the literature. In this work we report on the operation of a simple setup which provides the transverse magnetization of amorphous ribbons as a function of the current intensity flowing through it, by means of the magnetooptical kerr effect (MOKE). The system has been tested on low magnetostriction amorphous ribbons of very soft character with both longitudinal and transverse anisotropy. The transverse magnetization as a function of both the current and a DC longitudinal field applied, was compared with magneto impedance measurements
Improved approximate inspirals of test bodies into Kerr black holes
International Nuclear Information System (INIS)
Gair, Jonathan R; Glampedakis, Kostas
2006-01-01
We present an improved version of the approximate scheme for generating inspirals of test bodies into a Kerr black hole recently developed by Glampedakis, Hughes and Kennefick. Their original 'hybrid' scheme was based on combining exact relativistic expressions for the evolution of the orbital elements (the semilatus rectum p and eccentricity e) with an approximate, weak-field, formula for the energy and angular momentum fluxes, amended by the assumption of constant inclination angle ι during the inspiral. Despite the fact that the resulting inspirals were overall well behaved, certain pathologies remained for orbits in the strong-field regime and for orbits which are nearly circular and/or nearly polar. In this paper we eliminate these problems by incorporating an array of improvements in the approximate fluxes. First, we add certain corrections which ensure the correct behavior of the fluxes in the limit of vanishing eccentricity and/or 90 deg. inclination. Second, we use higher order post-Newtonian formulas, adapted for generic orbits. Third, we drop the assumption of constant inclination. Instead, we first evolve the Carter constant by means of an approximate post-Newtonian expression and subsequently extract the evolution of ι. Finally, we improve the evolution of circular orbits by using fits to the angular momentum and inclination evolution determined by Teukolsky-based calculations. As an application of our improved scheme, we provide a sample of generic Kerr inspirals which we expect to be the most accurate to date, and for the specific case of nearly circular orbits we locate the critical radius where orbits begin to decircularize under radiation reaction. These easy-to-generate inspirals should become a useful tool for exploring LISA data analysis issues and may ultimately play a role in the detection of inspiral signals in the LISA data
Hawking radiation of Dirac particles in the hot NUT-Kerr-Newman spacetime
International Nuclear Information System (INIS)
Ahmed, M.
1991-01-01
The Hawking radiation of charged Dirac particles on the horizons of the hot NUT-Kerr-Newman spacetime is studied in this paper. To this end, we obtain the radial decoupled Dirac equation for the electron in the hot NUT-Kerr-Newman spacetime. Next we solve the Dirac equation near the horizons. Finally, by analytic continuation, the Hawking thermal spectrum formula of Dirac particles is obtained. The problem of the Hawking evaporation of Dirac particles in the hot NUT-Kerr-Newman background is thus solved. (orig.)
Asymmetrical transverse structures in nonlinear interferometers
Romanov, O G
2003-01-01
The work presents a novel type of optical instability, which leads to the spontaneous formation of a stationary or pulsating asymmetrical structure in the problem of interaction between two counterpropagating waves in a ring cavity with Kerr-like nonlinearity. Linear stability analysis of interferometer transmission stationary states enabled: (1) to mark out typical bifurcations for this system: self- and cross-modulational instabilities, (2) to determine the range of parameters for which the symmetry breaking of transverse structures and complex temporal behaviour of the light field could be observed. The predictions of linear stability analysis have been verified with numerical modelling of coupled-modes equations.
C. Phillip Weatherspoon
1986-01-01
Ecological relationships-including habitat and life history---of giant sequoia (Sequoiadendron giganteum [Lindl.] Buchholz) in natural stands are summarized. Such silvical information provides an important foundation for sound management of the species.
International Nuclear Information System (INIS)
Loden, L.O.; Sundman, A.
1989-01-01
This study is part of an investigation of the possibility of using chemically peculiar (CP) stars to map local galactic structure. Correct luminosities of these stars are therefore crucial. CP stars are generally regarded as main-sequence or near-main-sequence objects. However, some CP stars have been classified as giants. A selection of stars, classified in literature as CP giants, are compared to normal stars in the same effective temperature interval and to ordinary 'non giant' CP stars. There is no clear confirmation of a higher luminosity for 'CP giants', than for CP stars in general. In addition, CP characteristics seem to be individual properties not repeated in a component star or other cluster members. (author). 50 refs., 5 tabs., 3 figs
Pérez-Guisado, Joaquín; Scilletta, Alessandra; Cabrera-Sánchez, Emilio; Rioja, Luis F; Perrotta, Rosario
2012-01-01
Epidermoid cysts represent the most common cutaneous cysts. They are usually small and benign; however, sometimes they can grow to giant epidermoid cists, and occasionally malignancies develop. Giant epidermoid cysts at the earlobe have never been described but in other locations. We describe a case of a giant epidermoid cyst at the earlobe, a location where such a large cyst has never been reported before. The mass was completely resected and the wound of the pedunculated base was sutured with four stitches of nylon 5/0. Histopathology confirmed the presumptive diagnosis of an epidermoid cyst. Six months after the resection, the patient did not have any relapse of the epidermoid cyst. The earlobe is a potential location for giant epidermoid cysts. Although the clinical diagnosis could be enough, due to the possibility of malignancy and to ensure appropriate diagnosis, we consider that all cysts should be sent to the anatomic pathology laboratory for histological evaluation. PMID:22557855
Directory of Open Access Journals (Sweden)
Joaquín Pérez-Guisado
2012-01-01
Full Text Available Epidermoid cysts represent the most common cutaneous cysts. They are usually small and benign; however, sometimes they can grow to giant epidermoid cists, and occasionally malignancies develop. Giant epidermoid cysts at the earlobe have never been described but in other locations. We describe a case of a giant epidermoid cyst at the earlobe, a location where such a large cyst has never been reported before. The mass was completely resected and the wound of the pedunculated base was sutured with four stitches of nylon 5/0. Histopathology confirmed the presumptive diagnosis of an epidermoid cyst. Six months after the resection, the patient did not have any relapse of the epidermoid cyst. The earlobe is a potential location for giant epidermoid cysts. Although the clinical diagnosis could be enough, due to the possibility of malignancy and to ensure appropriate diagnosis, we consider that all cysts should be sent to the anatomic pathology laboratory for histological evaluation.
International Nuclear Information System (INIS)
Maher, M.M.; Kennedy, J.; Hynes, D.; Murray, J.G.; O'Connell, D.
2000-01-01
We describe the imaging features of a giant geode of the distal humerus in a patient with rheumatoid arthritis, which presented initially as a pathological fracture. The value of magnetic resonance imaging in establishing this diagnosis is emphasized. (orig.)
Resonant magneto-optic Kerr effects of a single Ni nanorod in the Mie scattering regime.
Jeong, Ho-Jin; Kim, Dongha; Song, Jung-Hwan; Jeong, Kwang-Yong; Seo, Min-Kyo
2016-07-25
We present a systematic, theoretical investigation of the polar magneto-optical (MO) Kerr effects of a single Ni nanorod in the Mie regime. The MO Kerr rotation, ellipticity, amplitude ratio, and phase shift are calculated as a function of the length and width of the nanorod. The electric field amplitude ratio of the MO Kerr effect is locally maximized when the nanorod supports a plasmonic resonance in the polarization state orthogonal to the incident light. The plasmonic resonances directly induced by the incident light do not enhance the amplitude ratio. In the Mie regime, multiple local maxima of the MO Kerr activity are supported by the resonant modes with different modal characteristics. From the viewpoint of first-order perturbation analysis, the spatial overlap between the incident-light-induced electric field and the Green function determines the local maxima.
Eruptive Massive Vector Particles of 5-Dimensional Kerr-Gödel Spacetime
Övgün, A.; Sakalli, I.
2018-02-01
In this paper, we investigate Hawking radiation of massive spin-1 particles from 5-dimensional Kerr-Gödel spacetime. By applying the WKB approximation and the Hamilton-Jacobi ansatz to the relativistic Proca equation, we obtain the quantum tunneling rate of the massive vector particles. Using the obtained tunneling rate, we show how one impeccably computes the Hawking temperature of the 5-dimensional Kerr-Gödel spacetime.
General Tortoise Coordinate Transformation in a Dynamical Kerr-Newman Black Hole
Liu, Xian-Ming; Cheng, Su-Jun; Liu, Wen-Biao
2012-02-01
Under the extended dynamical tortoise coordinate transformation, Damour-Ruffini method has been applied to calculate the charged particles' Hawking radiation from the apparent horizon of a dynamical Kerr-Newman black hole. It is shown that Hawking radiation is still purely thermal black body spectrum. Moreover, the temperature of Hawking radiation is corresponding to the apparent horizon surface gravity and the first law of thermodynamics can also be constructed successfully on the apparent horizon in the dynamical Kerr-Newman black hole.
Counting the microstates of a Kerr black hole in M theory.
Horowitz, Gary T; Roberts, Matthew M
2007-11-30
We show that an extremal Kerr black hole, appropriately lifted to M theory, can be transformed to a Kaluza-Klein black hole in M theory, or a D0-D6 charged black hole in string theory. Since all the microstates of the latter have recently been identified, one can exactly reproduce the entropy of an extremal Kerr black hole. We also show that the topology of the event horizon is not well defined in M theory.
Optical nonlinearities of excitonic states in atomically thin 2D transition metal dichalcogenides
Energy Technology Data Exchange (ETDEWEB)
Soh, Daniel Beom Soo [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Proliferation Signatures Discovery and Exploitation Department
2017-08-01
We calculated the optical nonlinearities of the atomically thin monolayer transition metal dichalcogenide material (particularly MoS_{2}), particularly for those linear and nonlinear transition processes that utilize the bound exciton states. We adopted the bound and the unbound exciton states as the basis for the Hilbert space, and derived all the dynamical density matrices that provides the induced current density, from which the nonlinear susceptibilities can be drawn order-by-order via perturbative calculations. We provide the nonlinear susceptibilities for the linear, the second-harmonic, the third-harmonic, and the kerr-type two-photon processes.
Analytical study of a Kerr-Sen black hole and a charged massive scalar field
Bernard, Canisius
2017-11-01
It is reported that Kerr-Newman and Kerr-Sen black holes are unstable to perturbations of charged massive scalar field. In this paper, we study analytically the complex frequencies which characterize charged massive scalar fields in a near-extremal Kerr-Sen black hole. For near-extremal Kerr-Sen black holes and for charged massive scalar fields in the eikonal large-mass M ≫μ regime, where M is the mass of the black hole, and μ is the mass of the charged scalar field, we have obtained a simple expression for the dimensionless ratio ωI/(ωR-ωc) , where ωI and ωR are, respectively, the imaginary and real parts of the frequency of the modes, and ωc is the critical frequency for the onset of super-radiance. We have also found our expression is consistent with the result of Hod [Phys. Rev. D 94, 044036 (2016), 10.1103/PhysRevD.94.044036] for the case of a near-extremal Kerr-Newman black hole and the result of Zouros and Eardly [Ann. Phys. (N.Y.) 118, 139 (1979), 10.1016/0003-4916(79)90237-9] for the case of neutral scalar fields in the background of a near-extremal Kerr black hole.
Huang, Yang; Wu, Ya Min; Gao, Lei
2017-01-23
We carry out a theoretical study on optical bistability of near field intensity and transmittance in two-dimensional nonlinear composite slab. This kind of 2D composite is composed of nonlocal metal/Kerr-type dielectric core-shell inclusions randomly embedded in the host medium, and we derivate the nonlinear relation between the field intensity in the shell of inclusions and the incident field intensity with self-consistent mean field approximation. Numerical demonstration has been performed to show the viable parameter space for the bistable near field. We show that nonlocality can provide broader region in geometric parameter space for bistable near field as well as bistable transmittance of the nonlocal composite slab compared to local case. Furthermore, we investigate the bistable transmittance in wavelength spectrum, and find that besides the input intensity, the wavelength operation could as well make the transmittance jump from a high value to a low one. This kind of self-tunable nano-composite slab might have potential application in optical switching devices.
Energy Technology Data Exchange (ETDEWEB)
Fernández-Valdés, D.; Torres-Torres, C., E-mail: ctorrest@ipn.mx, E-mail: crstorres@yahoo.com.mx; Martínez-González, C. L. [Instituto Politécnico Nacional, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Ingeniería Mecánica y Eléctrica Unidad Zacatenco (Mexico); Trejo-Valdez, M. [Instituto Politécnico Nacional, Escuela Superior de Ingeniería Química e Industrias Extractivas (Mexico); Hernández-Gómez, L. H. [Instituto Politécnico Nacional, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Ingeniería Mecánica y Eléctrica Unidad Zacatenco (Mexico); Torres-Martínez, R. [Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada Unidad Querétaro (Mexico)
2016-07-15
The modification in the third-order nonlinear optical response exhibited by rotating bimetallic Au–Pt nanoparticles in an ethanol solution was analyzed. The samples were prepared by a sol–gel processing route. The anisotropy associated to the elemental composition of the nanoparticles was confirmed by high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy measurements. The size of the nanoparticles varies in the range from 9 to 13 nm, with an average size of 11 nm. Changes in the spatial orientation of the nanomaterials automatically generated a variation in their plasmonic response evaluated by UV–Vis spectroscopy. A two-wave mixing experiment was conducted to explore an induced birefringence at 532 nm wavelength with nanosecond pulses interacting with the samples. A strong optical Kerr effect was identified to be the main responsible effect for the third-order nonlinear optical phenomenon exhibited by the nanoparticles. It was estimated that the rotation of inhomogeneous nanostructures can provide a remarkable change in the participation of different surface plasmon resonances, if they correspond to multimetallic nanoparticles. Potential applications for developing low-dimensional gyroscopic systems can be contemplated.
Mudivarthi, Chaitanya
Fe--Ga alloys belong to a class of smart materials called magnetostrictive materials. Magnetostrictive materials show dimensional (magnetostriction) and magnetization changes in response to magnetic and elastic fields. These effects can be utilized for transduction purposes. Most widely used magnetostrictive materials like Tb-Dy-Fe (Terfenol-D) show giant magnetostriction (˜ 2000 muepsilon) but suffer from low modulus of elasticity, low tensile strength and are extremely brittle, limiting their usage to applications involving only axial loads. Fe--Ga alloys have recently been discovered to show an extraordinary enhancement in magnetostriction (from 36 muepsilon to 400 muepsilon) with the addition of the nonmagnetic element, Ga. Though their magnetostriction is less than that of Terfenol-D, they boast superior properties such as ductile-like behavior, high tensile strengths (˜ 400 MPa), low hysteresis, and low saturation fields (˜ 10 mT). Understanding the origin of the magnetostriction enhancement in these alloys is technologically and scientifically important because it will aid in our quest to discover alloys with higher magnetostriction (as Terfenol-D) and better mechanical properties (as Fe--Ga). With the goal of elucidating the nature of this unusually large magnetostriction enhancement, Fe--Ga solid solutions have recently been the focus of intense studies. All the studies so far, show the existence of nanoscale heterogeneities embedded in the cubic matrix but the experimental means to correlate the presence of nanoscale heterogeneities to the magnetostriction enhancement is lacking. In this work, Fe--Ga alloys of various compositions and heat treatments were probed at different length scales - lattice level, nano-, micro-, and macro-scales. Neutron diffraction was used to probe the alloy at the lattice level to identify the existence of different phases. Small-Angle Neutron Scattering (SANS) experiments were used to study the nanoscale heterogeneities and
Suryanto, A.; van Groesen, Embrecht W.C.; Hammer, Manfred; Hoekstra, Hugo
We present a simple numerical scheme based on the finite element method (FEM) using transparent-influx boundary conditions to study the nonlinear optical response of a finite one-dimensional grating with Kerr medium. Restricting first to the linear case, we improve the standard FEM to get a fourth
The Formation of Relativistic Jets from Kerr Black Holes
Nishikawa, K.-I.; Richardson, G.; Preece, R.; Hardee, P.; Koide, S.; Shibata, K.; Kudoh, T.; Sol, H.; Fishman, G. J.
2003-01-01
We have performed the first fully three-dimensional general relativistic magnetohydrodynamics (GRMHD) simulation for Schwarzschild and Kerr black holes with a free falling corona and thin accretion disk. The initial simulation results with a Schwarzschild metric show that a jet is created as in the previous axisymmetric simulations with mirror symmetry at the equator. However, the time to form the jet is slightly longer than in the 2-D axisymmetric simulation. We expect that the dynamics of jet formation are modified due to the additional freedom in the azimuth dimension without axisymmetry with respect to the Z axis and reflection symmetry respect to the equatorial plane. The jet which is initially formed due to the twisted magnetic fields and shocks becomes a wind at the later time. The wind flows out with a much wider angle than the initial jet. The twisted magnetic fields at the earlier time were untwisted and less pinched. The accretion disk became thicker than the initial condition. Further simulations with initial perturbations will provide insights for accretion dynamics with instabilities such as magneto-rotational instability (MRI) and accretion-eject instability (AEI). These instabilities may contribute to variabilities observed in microquasars and AGN jets.
Photon motion in Kerr-de Sitter spacetimes
Energy Technology Data Exchange (ETDEWEB)
Charbulak, Daniel; Stuchlik, Zdenek [Silesian University in Opava, Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Opava (Czech Republic)
2017-12-15
We study the general motion of photons in the Kerr-de Sitter black-hole and naked singularity spacetimes. The motion is governed by the impact parameters X, related to the axial symmetry of the spacetime, and q, related to its hidden symmetry. Appropriate 'effective potentials' governing the latitudinal and radial motion are introduced and their behavior is examined by the 'Chinese boxes' technique giving regions allowed for the motion in terms of the impact parameters. Restrictions on the impact parameters X and q are established in dependence on the spacetime parameters M, Λ, a. The motion can be of orbital type (crossing the equatorial plane, q > 0) and vortical type (tied above or below the equatorial plane, q < 0). It is shown that for negative values of q, the reality conditions imposed on the latitudinal motion yield stronger constraints on the parameter X than that following from the reality condition of the radial motion, excluding the existence of vortical motion of constant radius. The properties of the spherical photon orbits of the orbital type are determined and used along with the properties of the effective potentials as criteria of classification of the KdS spacetimes according to the properties of the motion of the photon. (orig.)
Neutrino oscillations in the Kerr-Newman spacetime
International Nuclear Information System (INIS)
Ren Jun; Zhang Chengmin
2010-01-01
The mass neutrino oscillation in the Kerr-Newman (K-N) spacetime is studied in the plane θ = θ 0 , and general equations of the oscillation phases are given. The effect of the rotation and electric charge on the phase is presented. Then, we consider three special cases. (1) The neutrinos travel along the geodesics with angular momentum L = aE in the equatorial plane. (2) The neutrinos travel along the geodesics with L = 0 in the equatorial plane. (3) The neutrinos travel along the radial geodesics in the direction θ = 0. Finally, we calculate the proper oscillation length in the K-N spacetime. The effect of the gravitational field on the oscillation length is embodied in the gravitational red shift factor. When the neutrino travels out of the gravitational field, a blue shift of the oscillation length takes place. We discuss the variation of the oscillation length influenced by the gravitational field strength, the rotation a 2 and charge Q.
Congenital giant melanocytic nevi
Directory of Open Access Journals (Sweden)
Shahla Khan
2009-07-01
Full Text Available Nevi are common skin tumors caused by abnormal overgrowth of cells from the epidermal and dermal layers of the skin. Most nevi are benign, but some pre-cancerous nevi must be monitored or removed. The giant congenital nevus is greater than 10 cm in size, pigmented and often hairy. Between 4% and 6% of these lesions will develop into a malignant melanoma. Since approximately 50% of the melanoma develop by the age of two, and 80% by the age of seven, early removal is recommended. The objective of this paper is to present a unique case of giant nevi and their surgical management.
Ferreira, Hugo R. C.; Herdeiro, Carlos A. R.
2018-04-01
It has been recently observed that a scalar field with Robin boundary conditions (RBCs) can trigger both a superradiant and a bulk instability for a Bañados-Teitelboim-Zanelli (BTZ) black hole (BH) [1]. To understand the generality and scrutinize the origin of this behavior, we consider here the superradiant instability of a Kerr BH confined either in a mirrorlike cavity or in anti-de Sitter (AdS) space, triggered also by a scalar field with RBCs. These boundary conditions are the most general ones that ensure the cavity/AdS space is an isolated system and include, as a particular case, the commonly considered Dirichlet boundary conditions (DBCs). Whereas the superradiant modes for some RBCs differ only mildly from the ones with DBCs, in both cases, we find that as we vary the RBCs the imaginary part of the frequency may attain arbitrarily large positive values. We interpret this growth as being sourced by a bulk instability of both confined geometries when certain RBCs are imposed to either the mirrorlike cavity or the AdS boundary, rather than by energy extraction from the BH, in analogy with the BTZ behavior.
Taming the nonlinearity of the Einstein equation.
Harte, Abraham I
2014-12-31
Many of the technical complications associated with the general theory of relativity ultimately stem from the nonlinearity of Einstein's equation. It is shown here that an appropriate choice of dynamical variables may be used to eliminate all such nonlinearities beyond a particular order: Both Landau-Lifshitz and tetrad formulations of Einstein's equation are obtained that involve only finite products of the unknowns and their derivatives. Considerable additional simplifications arise in physically interesting cases where metrics become approximately Kerr or, e.g., plane waves, suggesting that the variables described here can be used to efficiently reformulate perturbation theory in a variety of contexts. In all cases, these variables are shown to have simple geometrical interpretations that directly relate the local causal structure associated with the metric of interest to the causal structure associated with a prescribed background. A new method to search for exact solutions is outlined as well.
Numerical investigation of the late-time Kerr tails
International Nuclear Information System (INIS)
Racz, Istvan; Toth, Gabor Zs
2011-01-01
The late-time behavior of a scalar field on fixed Kerr background is examined in a numerical framework incorporating the techniques of conformal compactification and hyperbolic initial value formulation. The applied code is 1+(1+2) as it is based on the use of the spectral method in the angular directions while in the time-radial section fourth order finite differencing, along with the method of lines, is applied. The evolution of various types of stationary and non-stationary pure multipole initial states are investigated. The asymptotic decay rates are determined not only in the domain of outer communication but along the event horizon and at future null infinity as well. The decay rates are found to be different for stationary and non-stationary initial data, and they also depend on the fall off properties of the initial data toward future null infinity. The energy and angular momentum transfers are found to show significantly different behavior in the initial phase of the time evolution. The quasinormal ringing phase and the tail phase are also investigated. In the tail phase, the decay exponents for the energy and angular momentum losses at I + are found to be smaller than at the horizon which is in accordance with the behavior of the field itself and it means that at late times the energy and angular momentum falling into the black hole become negligible in comparison with the energy and angular momentum radiated toward I + . The energy and angular momentum balances are used as additional verifications of the reliability of our numerical method.
Bloembergen, Nicolaas
1996-01-01
Nicolaas Bloembergen, recipient of the Nobel Prize for Physics (1981), wrote Nonlinear Optics in 1964, when the field of nonlinear optics was only three years old. The available literature has since grown by at least three orders of magnitude.The vitality of Nonlinear Optics is evident from the still-growing number of scientists and engineers engaged in the study of new nonlinear phenomena and in the development of new nonlinear devices in the field of opto-electronics. This monograph should be helpful in providing a historical introduction and a general background of basic ideas both for expe
Ollenburger, Mary H.; Descheemaeker, Katrien; Crane, Todd A.; Sanogo, Ousmane M.; Giller, Ken E.
2016-01-01
The World Bank argued that West Africa's Guinea Savannah zone forms part of “Africa's Sleeping Giant,” where increases in agricultural production could be an engine of economic growth, through expansion of cultivated land in sparsely populated areas. The district of Bougouni, in southern Mali,
Directory of Open Access Journals (Sweden)
Vipul Yagnik
2011-07-01
Full Text Available Fibroadenomas are benign solid tumor associated with aberration of normal lobular development. Juvenile giant fibroadenoma is usually single and >5 cm in size /or >500 gms in weight. Important differential diagnoses are: phyllodes tumor and juvenile gigantomastia. Simple excision is the treatment of choice.
African Journals Online (AJOL)
STORAGESEVER
2009-06-03
Jun 3, 2009 ... RPS28 is a component of the 40S small ribosomal subunit encoded by RPS28 gene, which is specific to eukaryotes. The cDNA and the genomic sequence of RPS28 were cloned successfully from the Giant. Panda using RT-PCR technology and Touchdown-PCR, respectively. Both sequences were ...
Isotopic effect giant resonances
International Nuclear Information System (INIS)
Buenerd, M.; Lebrun, D.; Martin, P.; Perrin, G.; Saintignon, P. de; Chauvin, J.; Duhamel, G.
1981-10-01
The systematics of the excitation energy of the giant dipole, monopole, and quadrupole resonances are shown to exhibit an isotopic effect. For a given element, the excitation energy of the transition decreases faster with the increasing neutron number than the empirical laws fitting the overall data. This effect is discussed in terms of the available models
Nanodielectrics with giant permittivity
Indian Academy of Sciences (India)
Wintec
But the main limitation of the composite materials is its use in nanodevices. Therefore, few efforts have been ... an enormously high permittivity value of a sufficiently minute metal particle having discrete energy levels ... the present article is to assemble works on nanodielectrics with giant permittivity value, which have been ...
African Journals Online (AJOL)
Giant vesical calculus. A case report. H. H. LAUBSCHER. Summary. An exceptional case of bladder stone is presented. The case is unusual as regards the size of the stone and the fact that the patient did··not seek medical assistance much earlier, as this was readily avail- able. Furthermore, recovery after removal of the.
Indian Academy of Sciences (India)
Graphenes - Aromatic Giants. Ivan Gutman Boris Furtula. Volume 16 Issue 12 December 2011 pp 1238-1245. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/016/12/1238-1245. Keywords. Graphenes; polycyclic aromatic hydrocarbons; polyphenyls; condensed benzenes.
African Journals Online (AJOL)
2015-03-27
Mar 27, 2015 ... Giant peritoneal loose bodies are rare lesions, originating from auto-amputated appendices epiploicae. They may cause urinary or gastrointestinal obstruction and, should the radiologist not be familiar with the entity, can potentially be confused with malignant or parasitic lesions. Familiarity with their ...
International Nuclear Information System (INIS)
Bohigas, O.
1980-01-01
The giant resonances: electric dipolar E1, T=1, isoscalar electric quadrupolar E2, T=0 and isoscalar electric monopolar E0, T=0 are presented. The experimental facts are reviewed and some examples are given of the kind of information supplied by experimental data [fr
Generation of Caustics and Rogue Waves from Nonlinear Instability.
Safari, Akbar; Fickler, Robert; Padgett, Miles J; Boyd, Robert W
2017-11-17
Caustics are phenomena in which nature concentrates the energy of waves and may exhibit rogue-type behavior. Although they are known mostly in optics, caustics are intrinsic to all wave phenomena. As we demonstrate in this Letter, the formation of caustics and consequently rogue events in linear systems requires strong phase fluctuations. We show that nonlinear phase shifts can generate sharp caustics from even small fluctuations. Moreover, in that the wave amplitude increases dramatically in caustics, nonlinearity is usually inevitable. We perform an experiment in an optical system with Kerr nonlinearity, simulate the results based on the nonlinear Schrödinger equation, and achieve perfect agreement. As the same theoretical framework is used to describe other wave systems such as large-scale water waves, our results may also aid the understanding of ocean phenomena.
Super-entropic black holes and the Kerr-CFT correspondence
Energy Technology Data Exchange (ETDEWEB)
Sinamuli, Musema [Department of Physics and Astronomy, University of Waterloo,200 University Ave., Waterloo, Ontario N2L 3G1 (Canada); Perimeter Institute for Theoretical Physics,31 Caroline St., Waterloo, Ontario, N2L 2Y5 (Canada); Mann, Robert B. [Department of Physics and Astronomy, University of Waterloo,200 University Ave., Waterloo, Ontario N2L 3G1 (Canada)
2016-08-24
We demonstrate that Kerr-CFT duality can be extended to super-entropic black holes, which have non-compact horizons with finite area. We demonstrate that this duality is robust insofar as the ultra-spinning limit of a Kerr-AdS black hole (which yields the super-entropic class) commutes with the near-horizon limit (which yields the Kerr-CFT duality). Consequently the Bekenstein-Hawking and the CFT entropies are equivalent. We show that the duality holds for both singly-spinning super-entropic black holes in 4 dimensions and for doubly-spinning super-entropic black holes of gauged supergravity in 5 dimensions. In both cases we obtain not only the expected left/right temperatures, but also temperatures associated with electric charge and with a new thermodynamic parameter specific to super-entropic black holes.
Researching on Hawking Effect in a Kerr Space Time via Open Quantum System Approach
International Nuclear Information System (INIS)
Liu, Wen-Biao; Liu, Xian-Ming
2014-01-01
It has been proposed that Hawking radiation from a Schwarzschild or a de Sitter spacetime can be understood as the manifestation of thermalization phenomena in the framework of an open quantum system. Through examining the time evolution of a detector interacting with vacuum massless scalar fields, it is found that the detector would spontaneously excite with a probability the same as the thermal radiation at Hawking temperature. Following the proposals, the Hawking effect in a Kerr space time is investigated in the framework of an open quantum systems. It is shown that Hawking effect of the Kerr space time can also be understood as the the manifestation of thermalization phenomena via open quantum system approach. Furthermore, it is found that near horizon local conformal symmetry plays the key role in the quantum effect of the Kerr space time
Super-entropic black holes and the Kerr-CFT correspondence
International Nuclear Information System (INIS)
Sinamuli, Musema; Mann, Robert B.
2016-01-01
We demonstrate that Kerr-CFT duality can be extended to super-entropic black holes, which have non-compact horizons with finite area. We demonstrate that this duality is robust insofar as the ultra-spinning limit of a Kerr-AdS black hole (which yields the super-entropic class) commutes with the near-horizon limit (which yields the Kerr-CFT duality). Consequently the Bekenstein-Hawking and the CFT entropies are equivalent. We show that the duality holds for both singly-spinning super-entropic black holes in 4 dimensions and for doubly-spinning super-entropic black holes of gauged supergravity in 5 dimensions. In both cases we obtain not only the expected left/right temperatures, but also temperatures associated with electric charge and with a new thermodynamic parameter specific to super-entropic black holes.
Deflection of light in equatorial plane due to Kerr-Taub-NUT body
Directory of Open Access Journals (Sweden)
Chakraborty Sarani
2017-01-01
Full Text Available According to General Relativity, there are factors like mass, rotation, charge and presence of Cosmological constant that can influence the path of light ray. Apart from these factors, many authors have also reported the influence of gravitomagnetism on the path of light ray. In this study we have discussed the effect of a rotating Kerr-Taub-NUT body where the strength of the gravitomagnetic monopole is represented by the NUT factor or magnetic mass. We use the null geodesic of photon method to obtain the deflection angle of light ray for a Kerr-Taub-NUT body in equatorial plane upto the fourth order term. Our study shows that the NUT factor has a noticeable effect on the path of the light ray. By considering the magnetism to be zero, the expression of bending angle gets reduced to the Kerr bending angle. However, we obtained a non-zero bending angle for a hypothetical massless, magnetic body.
Euler Characteristic and Topological Phase Transition of NUT-Kerr-Newman Black Hole
International Nuclear Information System (INIS)
Ye Jinghua; Yang Guohong; Tian Lijun; Zhu Shu
2008-01-01
From the Gauss-Bonnet-Chern theorem, the Euler characteristic of NUT-Kerr-Newman black hole is calculated to be some discrete numbers from 0 to 2. We find that the Bekenstein-Hawking entropy is the largest entropy in topology by taking into account of the relationship between the entropy and the Euler characteristic. The NUT-Kerr-Newman black hole evolves from the torus-like topological structure to the spherical structure with the changes of mass, angular momentum, electric and NUT charges. In this process, the Euler characteristic and the entropy are changed discontinuously, which give the topological aspect of the first-order phase transition of NUT-Kerr-Newman black hole. The corresponding latent heat of the topological phase transition is also obtained. The estimated latent heat of the black hole evolving from the star just lies in the range of the energy of gamma ray bursts
Electric-Magneto-Optical Kerr Effect in a Hybrid Organic-Inorganic Perovskite.
Fan, Feng-Ren; Wu, Hua; Nabok, Dmitrii; Hu, Shunbo; Ren, Wei; Draxl, Claudia; Stroppa, Alessandro
2017-09-20
Hybrid organic-inorganic compounds attract a lot of interest for their flexible structures and multifunctional properties. For example, they can have coexisting magnetism and ferroelectricity whose possible coupling gives rise to magnetoelectricity. Here using first-principles computations, we show that, in a perovskite metal-organic framework (MOF), the magnetic and electric orders are further coupled to optical excitations, leading to an Electric tuning of the Magneto-Optical Kerr effect (EMOKE). Moreover, the Kerr angle can be switched by reversal of both ferroelectric and magnetic polarization only. The interplay between the Kerr angle and the organic-inorganic components of MOFs offers surprising unprecedented tools for engineering MOKE in complex compounds. Note that this work may be relevant to acentric magnetic systems in general, e.g., multiferroics.
A general theory of two-wave mixing in nonlinear media
DEFF Research Database (Denmark)
Chi, Mingjun; Huignard, Jean-Pierre; Petersen, Paul Michael
2009-01-01
A general theory of two-wave mixing in nonlinear media is presented. Assuming a gain (or absorption) grating and a refractive index grating are generated because of the nonlinear process in a nonlinear medium, the coupled-wave equations of two-wave mixing are derived based on the Maxwell’s wave...... to the previous theory of two-wave mixing, the theory presented here is more general and the application of the theory to the photorefractive materials, Kerr media and semiconductor broad-area amplifiers are described....
Designing Kerr interactions using multiple superconducting qubit types in a single circuit
Elliott, Matthew; Joo, Jaewoo; Ginossar, Eran
2018-02-01
The engineering of Kerr interactions is of great interest for processing quantum information in multipartite quantum systems and for investigating many-body physics in a complex cavity-qubit network. We study how coupling multiple different types of superconducting qubits to the same cavity modes can be used to modify the self- and cross-Kerr effects acting on the cavities and demonstrate that this type of architecture could be of significant benefit for quantum technologies. Using both analytical perturbation theory results and numerical simulations, we first show that coupling two superconducting qubits with opposite anharmonicities to a single cavity enables the effective self-Kerr interaction to be diminished, while retaining the number splitting effect that enables control and measurement of the cavity field. We demonstrate that this reduction of the self-Kerr effect can maintain the fidelity of coherent states and generalised Schrödinger cat states for much longer than typical coherence times in realistic devices. Next, we find that the cross-Kerr interaction between two cavities can be modified by coupling them both to the same pair of qubit devices. When one of the qubits is tunable in frequency, the strength of entangling interactions between the cavities can be varied on demand, forming the basis for logic operations on the two modes. Finally, we discuss the feasibility of producing an array of cavities and qubits where intermediary and on-site qubits can tune the strength of self- and cross-Kerr interactions across the whole system. This architecture could provide a way to engineer interesting many-body Hamiltonians and be a useful platform for quantum simulation in circuit quantum electrodynamics.
Directory of Open Access Journals (Sweden)
Teresa Cristina S. Anacleto
2001-09-01
Full Text Available The diel of the giant armadillo - Priodontes maximus (Kerr,1792 - was studied in the field at Fazenda São Miguel, Unaí, Minas Gerais, Brazil, through 82 samples collected at foraging excavations and 25 fecal samples. In both types of sample the most common item was insects (Isoptera e Hymenoptera and, in less quantity, plant fragments and orhers invertebrates (Aranae, Blattaria, Coleoptera, Diplopoda, Scorpiones. These data suggest the giant armadillo is a specialist on insects with an opportunistic foraging strategy.
Massive vector particles tunneling from Kerr and Kerr–Newman black holes
Directory of Open Access Journals (Sweden)
Xiang-Qian Li
2015-12-01
Full Text Available In this paper, we investigate the Hawking radiation of massive spin-1 particles from 4-dimensional Kerr and Kerr–Newman black holes. By applying the Hamilton–Jacobi ansatz and the WKB approximation to the field equations of the massive bosons in Kerr and Kerr–Newman space-time, the quantum tunneling method is successfully implemented. As a result, we obtain the tunneling rate of the emitted vector particles and recover the standard Hawking temperature of both the two black holes.
Quasi-normal modes for Dirac fields in Kerr-Newman-de Sitter black holes
Iantchenko, Alexei
2015-01-01
We provide the full asymptotic description of the quasi-normal modes (resonances) in any strip of fixed width for Dirac fields in slowly rotating Kerr-Newman-de Sitter black holes. The resonances split in a way similar to the Zeeman effect. The method is based on the extension to Dirac operators of techniques applied by Dyatlov 2011, 2012 to the (uncharged) Kerr-de Sitter black holes. We show that the mass of the Dirac field does not have effect on the two leading terms in the expansions of r...
CFT description of three-dimensional Kerr-de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Fjelstad, Jens E-mail: jens.fjelstad@kau.se; Hwang, Stephen E-mail: stephen.hwang@kau.se; Maansson, Teresia E-mail: teresia@physto.se
2002-10-07
We describe three-dimensional Kerr-de Sitter space using similar methods as recently applied to the BTZ black hole. A rigorous form of the classical connection between gravity in three dimensions and two-dimensional conformal field theory is employed, where the fundamental degrees of freedom are described in terms of two dependent SL(2,C) currents. In contrast to the BTZ case, however, quantization does not give the Bekenstein-Hawking entropy connected to the cosmological horizon of Kerr-de Sitter space.
CFT description of three-dimensional Kerr-de Sitter spacetime
International Nuclear Information System (INIS)
Fjelstad, Jens; Hwang, Stephen; Maansson, Teresia
2002-01-01
We describe three-dimensional Kerr-de Sitter space using similar methods as recently applied to the BTZ black hole. A rigorous form of the classical connection between gravity in three dimensions and two-dimensional conformal field theory is employed, where the fundamental degrees of freedom are described in terms of two dependent SL(2,C) currents. In contrast to the BTZ case, however, quantization does not give the Bekenstein-Hawking entropy connected to the cosmological horizon of Kerr-de Sitter space
Energy extraction from a Konoplya–Zhidenko rotating non-Kerr black hole
Directory of Open Access Journals (Sweden)
Fen Long
2018-01-01
Full Text Available We have investigated the properties of the ergosphere and the energy extraction by Penrose process in a Konoplya–Zhidenko rotating non-Kerr black hole spacetime. We find that the ergosphere becomes thin and the maximum efficiency of energy extraction decreases as the deformation parameter increases. For the case with aM, we find that the maximum efficiency can reach so high that it is almost unlimited as the positive deformation parameter is close to zero, which is a new feature of energy extraction in such kind of rotating non-Kerr black hole spacetime.
Yoshida, Zensho
2010-01-01
This book gives a general, basic understanding of the mathematical structure "nonlinearity" that lies in the depths of complex systems. Analyzing the heterogeneity that the prefix "non" represents with respect to notions such as the linear space, integrability and scale hierarchy, "nonlinear science" is explained as a challenge of deconstruction of the modern sciences. This book is not a technical guide to teach mathematical tools of nonlinear analysis, nor a zoology of so-called nonlinear phenomena. By critically analyzing the structure of linear theories, and cl
Nayfeh, Ali Hasan
1995-01-01
Nonlinear Oscillations is a self-contained and thorough treatment of the vigorous research that has occurred in nonlinear mechanics since 1970. The book begins with fundamental concepts and techniques of analysis and progresses through recent developments and provides an overview that abstracts and introduces main nonlinear phenomena. It treats systems having a single degree of freedom, introducing basic concepts and analytical methods, and extends concepts and methods to systems having degrees of freedom. Most of this material cannot be found in any other text. Nonlinear Oscillations uses sim
Schenk C.; Staib E.
1992-01-01
We are in the second year of fieldwork surveying for Giant Otters in the southeastern rainforest of Peru, in three areas with differing levels of legal protection. While there is some illegal hunting still happening outside the protected areas, the main threat to the otters is badly-conducted tourism. Well-organised tourism can be a promising argument for establishing protected areas like national parks.
Intraoral giant condyloma acuminatum
Directory of Open Access Journals (Sweden)
Gupta R
2001-09-01
Full Text Available A case of intraoral giant condyloma acuminatum is reported in a 50- year- old Indian. He did not respond to topical application of podophyllin 20% but responded partially to electric cauterisation. Surgical excision was done to get rid of the warty growh completely. Since there were no skin or genital lesions and no history of marital or extramarital sexual contact the lesion was probably acquired from environmental sources. Nonsexual transmission should be considered especially when the lesions are extragenital.
DEFF Research Database (Denmark)
Delgrange, Etienne; Raverot, Gerald; Bex, Marie
2014-01-01
OBJECTIVE: To characterise distinctive clinical features of giant prolactinomas in women. DESIGN: A multicentre, retrospective case series and literature review. METHODS: We collected data from 15 female patients with a pituitary tumour larger than 4 cm and prolactin levels above 1000 μg/l and id......OBJECTIVE: To characterise distinctive clinical features of giant prolactinomas in women. DESIGN: A multicentre, retrospective case series and literature review. METHODS: We collected data from 15 female patients with a pituitary tumour larger than 4 cm and prolactin levels above 1000 μg....../l and identified 19 similar cases from the literature; a gender-based comparison of the frequency and age distribution was obtained from a literature review. RESULTS: The initial PubMed search using the term 'giant prolactinomas' identified 125 patients (13 women) responding to the inclusion criteria. The female......:male ratio was 1:9. Another six female patients were found by extending the literature search, while our own series added 15 patients. The median age at diagnosis was 44 years in women compared with 35 years in men (Pwomen (n=34), we...
International Nuclear Information System (INIS)
Carrillo-Delgado, C; Torres-Torres, C; García-Merino, J A; García-Gil, C I; Khomenko, A V; Trejo-Valdez, M; Martínez-Gutiérrez, H; Torres-Martínez, R
2016-01-01
Measurements of the third-order nonlinear optical properties exhibited by a ZnO thin solid film deposited on a SnO 2 substrate are presented. The samples were prepared by a spray pyrolysis processing route. Scanning electron microscopy analysis and UV–Vis spectroscopy studies were carried out. The picosecond response at 1064 nm was explored by the z-scan technique. A large optical Kerr effect with two-photon absorption was obtained. The inhibition of the nonlinear optical absorption together with a noticeable enhancement in the optical Kerr effect in the sample was achieved by the incorporation of Au nanoparticles into the ZnO film. Additionally, a two-wave mixing configuration at 532 nm was performed and an optical Kerr effect was identified as the main cause of the nanosecond third-order optical nonlinearity. The relaxation time of the photothermal response of the sample was estimated to be about 1 s when the sample was excited by nanosecond single-shots. The rotation of the sample during the nanosecond two-wave mixing experiments was analyzed. It was stated that a non-monotonic relation between rotating frequency and pulse repetition rate governs the thermal contribution to the nonlinear refractive index exhibited by a rotating film. Potential applications for switching photothermal interactions in rotating samples can be contemplated. A rotary logic system dependent on Kerr transmittance in a two-wave mixing experiment was proposed. (paper)
de Mello Koch, Robert; Nkumane, Lwazi
2018-02-01
We identify the operators in N = 4 super Yang-Mills theory that correspond to 1/8 -BPS giant gravitons in AdS5 × S 5. Our evidence for the identification comes from (1) counting these operators and showing agreement with independent counts of the number of giant graviton states, and (2) by demonstrating a correspondence between correlation functions of the super Yang-Mills operators and overlaps of the giant graviton wave functions.
Giant oilfields and civil conflict
Yu-Hsiang Lei; Guy Michaels
2012-01-01
We use new data to examine the effects of giant oilfield discoveries around the world since 1946. On average, these discoveries increase per capita oil production and oil exports by up to 50 percent. But these giant oilfield discoveries also have a dark side: they increase the incidence of internal armed conflict by about 5-8 percentage points. This increased incidence of conflict due to giant oilfield discoveries is especially high for countries that had already experienced armed conflicts o...
National Research Council Canada - National Science Library
Rassias, Themistocles M
1987-01-01
... known that nonlinear partial differential equations can not be treated in the same systematic way as linear ones and this volume provides, among other things, proofs of existence and uniqueness theorems for nonlinear differential equations of a global nature. However, the basic techniques which have proven to be efficient in dealing with li...
Palmero, Faustino; Lemos, M; Sánchez-Rey, Bernardo; Casado-Pascual, Jesús
2018-01-01
This book presents an overview of the most recent advances in nonlinear science. It provides a unified view of nonlinear properties in many different systems and highlights many new developments. While volume 1 concentrates on mathematical theory and computational techniques and challenges, which are essential for the study of nonlinear science, this second volume deals with nonlinear excitations in several fields. These excitations can be localized and transport energy and matter in the form of breathers, solitons, kinks or quodons with very different characteristics, which are discussed in the book. They can also transport electric charge, in which case they are known as polarobreathers or solectrons. Nonlinear excitations can influence function and structure in biology, as for example, protein folding. In crystals and other condensed matter, they can modify transport properties, reaction kinetics and interact with defects. There are also engineering applications in electric lattices, Josephson junction a...
Extended Kerr-Schild spacetimes: general properties and some explicit examples
Czech Academy of Sciences Publication Activity Database
Málek, Tomáš
2014-01-01
Roč. 31, č. 18 (2014), s. 185013 ISSN 0264-9381 R&D Projects: GA ČR GB14-37086G Institutional support: RVO:67985840 Keywords : Kerr-Schild spacetimes * algebraic classification * higher dimensions Subject RIV: BA - General Mathematics Impact factor: 3.168, year: 2014 http://iopscience.iop.org/0264-9381/31/18/185013/
On the instability regime of the rotating Kerr spacetime to massive scalar perturbations
International Nuclear Information System (INIS)
Hod, Shahar
2012-01-01
The instability of rotating Kerr black holes due to massive scalar perturbations is investigated. It is well known that a bosonic field impinging on a Kerr black hole can be amplified as it scatters off the hole. This superradiant scattering occurs for frequencies in the range ω< mΩ, where Ω is the angular frequency of the black hole and m is the azimuthal harmonic index of the mode. If the incident field has a non-zero rest mass, μ, then the mass term effectively works as a mirror, reflecting the scattered wave back towards the black hole. The wave may bounce back and forth between the black hole and some turning point amplifying itself each time. This may lead to a dynamical instability of the system, a phenomena known as a “black-hole bomb”. In this work we provide a bound on the instability regime of rotating Kerr spacetimes. In particular, we show that Kerr black holes are stable to massive perturbations in the regime μ⩾√(2)mΩ.
Separability and Killing tensors in Kerr-Taub-NUT-de Sitter metrics in higher dimensions
International Nuclear Information System (INIS)
Chong, Z.-W.; Gibbons, G.W.; Lue, H.; Pope, C.N.
2005-01-01
A generalisation of the four-dimensional Kerr-de Sitter metrics to include a NUT charge is well known, and is included within a class of metrics obtained by Plebanski. In this Letter, we study a related class of Kerr-Taub-NUT-de Sitter metrics in arbitrary dimensions D>=6, which contain three non-trivial continuous parameters, namely the mass, the NUT charge, and a (single) angular momentum. We demonstrate the separability of the Hamilton-Jacobi and wave equations, we construct a closely-related rank-2 Stackel-Killing tensor, and we show how the metrics can be written in a double Kerr-Schild form. Our results encompass the case of the Kerr-de Sitter metrics in arbitrary dimension, with all but one rotation parameter vanishing. Finally, we consider the real Euclidean-signature continuations of the metrics, and show how in a limit they give rise to certain recently-obtained complete non-singular compact Einstein manifolds
International Nuclear Information System (INIS)
Zheltikov, Aleksei M; Koroteev, Nikolai I; Naumov, A N; Fedotov, Andrei B; Magnitskiy, Sergey A; Sidorov-Biryukov, D A
1998-01-01
An investigation was made of the characteristics of the optical Kerr effect in a spiropyran solution. It was found that this effect makes it possible to distinguish the coloured and uncoloured forms of spiropyran and that it represents a promising method for nondestructive data reading in three-dimensional optical memory systems based on photochromic materials. (letters to the editor)
On the energy emission by a Kerr black hole in the superradiant range
International Nuclear Information System (INIS)
Curir, A.
1985-01-01
A new redefined ''Unruh vacuum'' has been used in order to obtain the thermal Hawkin emission in a Kerr geometry in the superradiant range. It is also shown that a new type of vacuum is needed to obtain the global emission from a rotating black hole in the superradiant range. The formula describing such global emission is given. (orig.)
Life as the Middle Child: A Conversation With Mary Margaret Kerr
Teagarden, James M.; Zabel, Robert H.; Kaff, Marilyn S.
2015-01-01
As part of an ongoing oral history project, a conversation was held with Dr. Mary Margaret Kerr on the past, present, and possible future of the field of providing services to children with emotional-behavioral disorders. Dr. Wood stresses the increasing importance of providing an interdisciplinary approach to meet the needs for children or, as…
Clark Kerr's Multiversity and Technology Transfer in the Modern American Research University
Sigurdson, Kristjan T.
2013-01-01
In the early 1960s, Clark Kerr, the famed American educationalist and architect of the California public higher education system, took up the task of describing the emergent model of the contemporary American university. Multiversities, as he called them, were the large powerful American universities that packaged the provision of undergraduate,…
Generic features of modulational instability in nonlocal Kerr media
DEFF Research Database (Denmark)
Wyller, John; Krolikowski, Wieslaw; Bang, Ole
2002-01-01
the nonlocality tends to suppress MI, but can never remove it completely, irrespectively of the shape of the response function. For a defocusing nonlinearity the stability properties depend sensitively on the profile of the response function. For response functions with a positive-definite spectrum......, such as Gaussians and exponentials, plane waves are always stable, whereas response functions with spectra that are not positive definite (such as the rectangular) will lead to MI if sigma exceeds a certain threshold. For the square response function, in both the focusing and defocusing case, we show analytically...
Boyd, Robert W
2013-01-01
Nonlinear Optics is an advanced textbook for courses dealing with nonlinear optics, quantum electronics, laser physics, contemporary and quantum optics, and electrooptics. Its pedagogical emphasis is on fundamentals rather than particular, transitory applications. As a result, this textbook will have lasting appeal to a wide audience of electrical engineering, physics, and optics students, as well as those in related fields such as materials science and chemistry.Key Features* The origin of optical nonlinearities, including dependence on the polarization of light* A detailed treatment of the q
Directory of Open Access Journals (Sweden)
Alka Gupta
2017-07-01
Full Text Available Paraganglioma is a rare neuroendocrine catecholamine producing tumour in childhood which arises outside the adrenal medulla. We present a 12 year old girl with giant paraganglioma with severe hypertension and end organ damage. Diagnosis was confirmed with 24 h urinary Vanillymandelic Acid (VMA and CT scan. Preoperative blood pressure was controlled with intravenous nitroprusside, and oral prazosin, amlodepine, labetalol and metoprolol. General anaesthesia with epidural analgesia was given. Intra operative blood pressure rise was managed with infusion of nitriglycerine (NTG, esmolol, nitroprusside and propofol.
GIANT INTRACANALICULAR FIBROADENOMA
Smith, Clyn; Parsons, Robert J.; Bogart, William M.
1951-01-01
Five cases of giant intracanalicular fibroadenoma (“cystosarcoma phylloides”) were observed at one hospital in a period of three years. In a search of the literature, additional reports of breast tumors of this kind, not included in previous reviews, were noted. As there is record of 229 cases, it would appear that this rapidly growing benign tumor should be kept in mind in the diagnosis of masses in the breast. If removal is incomplete, there may be recurrence. Simple mastectomy is the treatment of choice. Radical mastectomy should be avoided. ImagesFigure 1Figure 2.Figure 3Figure 4Figure 5 PMID:14848732
Giant Ulcerative Dermatofibroma
Directory of Open Access Journals (Sweden)
Turgut Karlidag
2013-01-01
Full Text Available Dermatofibroma is a slowly growing common benign cutaneous tumor characterized by hard papules and nodules. The rarely seen erosions and ulcerations may cause difficulties in the diagnosis. Dermatofibrosarcoma protuberans, which is clinically and histopathologically of malignant character, displays difficulties in the diagnosis since it has similarities with basal cell carcinoma, epidermoid carcinoma, and sarcomas. Head and neck involvement is very rare. In this study, a giant dermatofibroma case, which is histopathologically, ulcerative dermatofibroma, the biggest lesion of the head and neck region and seen rarely in the literature that has characteristics similar to dermatofibrosarcoma protuberans, has been presented.
GIANT PROSTHETIC VALVE THROMBUS
Directory of Open Access Journals (Sweden)
Prashanth Kumar
2015-04-01
Full Text Available Mechanical prosthetic valves are predisposed to bleeding, thrombosis & thromboembolic complications. Overall incidence of thromboembolic complications is 1% per year who are on oral anticoagulants, whereas bleeding complications incidence is 0.5% to 6.6% per year. 1, 2 Minimization of Scylla of thromboembolic & Charybdis of bleeding complication needs a balancing act of optimal antithrombotic therapy. We are reporting a case of middle aged male patient with prosthetic mitral valve presenting in heart failure. Patient had discontinued anticoagulants, as he had subdural hematoma in the past. He presented to our institute with a giant prosthetic valve thrombus.
Sigdel, G; Agarwal, A; Keshaw, B W
2014-01-01
Urethral calculi are rare forms of urolithiasis. Majority of the calculi are migratory from urinary bladder or upper urinary tract. Primary urethral calculi usually occur in presence of urethral stricture or diverticulum. In this article we report a case of a giant posterior urethral calculus measuring 7x3x2 cm in a 47 years old male. Patient presented with acute retention of urine which was preceded by burning micturition and dribbling of urine for one week. The calculus was pushed in to the bladder through the cystoscope and was removed by suprapubic cystolithotomy.
Giant Congenital Melanocytic Nevus
DEFF Research Database (Denmark)
Rasmussen, Bo Sonnich; Henriksen, Trine Foged; Kølle, Stig-Frederik Trojahn
2015-01-01
Giant congenital melanocytic nevi (GCMN) occur in 1:20,000 livebirths and are associated with increased risk of malignant transformation. The treatment of GCMN from 1981 to 2010 in a tertiary referral center was reviewed evaluating the modalities used, cosmetic results, associated complications......% versus 44% required unplanned additional surgery, respectively. Complications were noted in 25% and 67% of the patients, respectively. Cosmetic result was satisfying in 76% of patients without difference between the groups. No malignant transformation was found during a mean follow-up of 11 years....... Curettage is a gentle alternative to excision with a lower complication rate and good cosmetic outcome....
Zhu, Hong-Ming; Yu, Yu; Pen, Ue-Li; Chen, Xuelei; Yu, Hao-Ran
2017-12-01
We present a direct approach to nonparametrically reconstruct the linear density field from an observed nonlinear map. We solve for the unique displacement potential consistent with the nonlinear density and positive definite coordinate transformation using a multigrid algorithm. We show that we recover the linear initial conditions up to the nonlinear scale (rδrδL>0.5 for k ≲1 h /Mpc ) with minimal computational cost. This reconstruction approach generalizes the linear displacement theory to fully nonlinear fields, potentially substantially expanding the baryon acoustic oscillations and redshift space distortions information content of dense large scale structure surveys, including for example SDSS main sample and 21 cm intensity mapping initiatives.
Gasinski, Leszek
2005-01-01
Hausdorff Measures and Capacity. Lebesgue-Bochner and Sobolev Spaces. Nonlinear Operators and Young Measures. Smooth and Nonsmooth Analysis and Variational Principles. Critical Point Theory. Eigenvalue Problems and Maximum Principles. Fixed Point Theory.
2016-07-01
architectures , practical nonlinearities, nonlinear dynamics 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT: SAR 8. NUMBER OF PAGES...performers from Mesodynamic Architectures (MESO) and uPNT all to include devices in these runs. This cost-sharing was planned, and is necessary for...contributions to the performance of MEMS gyroscopes. In particular, we have demonstrated for the first time that Parametric Amplification can improve the
Xu, Tianhua; Karanov, Boris; Shevchenko, Nikita A; Lavery, Domaniç; Liga, Gabriele; Killey, Robert I; Bayvel, Polina
2017-10-11
Nyquist-spaced transmission and digital signal processing have proved effective in maximising the spectral efficiency and reach of optical communication systems. In these systems, Kerr nonlinearity determines the performance limits, and leads to spectral broadening of the signals propagating in the fibre. Although digital nonlinearity compensation was validated to be promising for mitigating Kerr nonlinearities, the impact of spectral broadening on nonlinearity compensation has never been quantified. In this paper, the performance of multi-channel digital back-propagation (MC-DBP) for compensating fibre nonlinearities in Nyquist-spaced optical communication systems is investigated, when the effect of signal spectral broadening is considered. It is found that accounting for the spectral broadening effect is crucial for achieving the best performance of DBP in both single-channel and multi-channel communication systems, independent of modulation formats used. For multi-channel systems, the degradation of DBP performance due to neglecting the spectral broadening effect in the compensation is more significant for outer channels. Our work also quantified the minimum bandwidths of optical receivers and signal processing devices to ensure the optimal compensation of deterministic nonlinear distortions.
International Nuclear Information System (INIS)
Bhadra, Jhumpa; Debnath, Ujjal
2012-01-01
In this work, we have studied accretion of the dark energies in new variable modified Chaplygin gas (NVMCG) and generalized cosmic Chaplygin gas (GCCG) models onto Schwarzschild and Kerr-Newman black holes. We find the expression of the critical four velocity component which gradually decreases for the fluid flow towards the Schwarzschild as well as the Kerr-Newman black hole. We also find the expression for the change of mass of the black hole in both cases. For the Kerr-Newman black hole, which is rotating and charged, we calculate the specific angular momentum and total angular momentum. We showed that in both cases, due to accretion of dark energy, the mass of the black hole increases and angular momentum increases in the case of a Kerr-Newman black hole. (orig.)
The spinning Kerr-black-hole-mirror bomb: A lower bound on the radius of the reflecting mirror
Hod, Shahar
2016-01-01
The intriguing superradiant amplification phenomenon allows an orbiting scalar field to extract rotational energy from a spinning Kerr black hole. Interestingly, the energy extraction rate can grow exponentially in time if the black-hole-field system is placed inside a reflecting mirror which prevents the field from radiating its energy to infinity. This composed Kerr-black-hole-scalar-field-mirror system, first designed by Press and Teukolsky, has attracted the attention of physicists over t...
Induced Kerr effects and self-guided beams in quasi-phase-matched quadratic media [CBC4
DEFF Research Database (Denmark)
Clausen, Carl A. Balslev; Bang, Ole; Kivshar, Yuri S.
1997-01-01
We show that quasi-phase-matching of quadratic media induces Kerr effects, such as self- and cross-phase modulation, and leads to the existence of a novel class of solitary waves, QPM-solitons......We show that quasi-phase-matching of quadratic media induces Kerr effects, such as self- and cross-phase modulation, and leads to the existence of a novel class of solitary waves, QPM-solitons...
International Nuclear Information System (INIS)
Tang, F.; Liu, D.-L.; Ye, D.-X.; Lu, T.-M.; Wang, G.-C.
2004-01-01
Magneto-optical Kerr effect (MOKE) in the longitudinal mode was used to measure the in-plane magnetic anisotropy of about 300nm thick Co nano-column films that were grown by e-beam evaporation at different oblique incident angles (0-85 o ) on native SiO 2 substrates at room temperature. The symmetry of MOKE loops measured at azimuthal angles that are 180 o apart is obviously broken for Co nano-column films grown at high deposition angles >70 o . The plot of coercivity H c of loops versus azimuthal angle shows that H c values for azimuthal angles between -90 o and 90 o are much larger than the values for azimuthal angles between 90 o and 270 o . The asymmetry of coercivity is due to MOKE measurement that combines both longitudinal and polar Kerr effects. This combination is caused by the oblique magnetic anisotropy associated with the tilted Co nano-columns. A method is introduced to separate the longitudinal and polar Kerr effects. The longitudinal Kerr effect is obtained by adding hysteresis loops measured at azimuthal angles 180 o apart while the polar Kerr effect is obtained by subtracting these two loops. By comparing these two orthogonal magnetization components represented by longitudinal and polar Kerr effects, we show that magnetization rotation exists in the magnetic reversal process even at azimuthal angle φ=0 o that is the closest in-plane direction to the easy axis. After separating these two Kerr effects, the two-fold symmetry of coervicity associated with tilted nano-columns measured by longitudinal Kerr effect is restored
International Nuclear Information System (INIS)
Chen Yuanfu; Mei Yongfeng; Malachias, Angelo; Ingolf Moench, Jens; Kaltofen, Rainer; Schmidt, Oliver G
2008-01-01
By introducing a photoresist buffer layer, the enhancement of giant magnetoresistance (GMR) values of Co/Cu multilayers deposited on oxidized Si substrates is up to around 365%. X-ray reflectivity measurements indicate that the interfacial roughness of Co/Cu bilayer stacks buffered with a photoresist layer is lower than that on bare oxidized Si substrates, although their surface roughnesses are similar. Magneto-optical Kerr effect hysteresis loops of (Co/Cu) N multilayers show that the antiferromagnetic coupling strength and fraction were significantly improved after photoresist buffering for all samples with N ranging from 8 to 50. The interface smoothening of photoresist-buffered multilayers may therefore contribute to such an enhancement, which in turn increases the corresponding GMR values. (fast track communication)
Recurrent giant juvenile fibroadenoma
Directory of Open Access Journals (Sweden)
Kathryn S. King
2017-11-01
Full Text Available Breast masses in children, though rare, present a difficult clinical challenge as they can represent a wide variety of entities from benign fibroadenomas to phyllodes tumors. Rapidly growing or recurrent masses can be particularly concerning to patients, families and physicians alike. Clinical examination and conventional imaging modalities are not efficacious in distinguishing between different tumor types and surgical excision is often recommended for both final diagnosis and for treatment of large or rapidly growing masses. While surgical excision can result in significant long-term deformity of the breast there are some surgical techniques that can be used to limit deformity and/or aid in future reconstruction. Here we present a case of recurrent giant juvenile fibroadenoma with a review of the clinical presentation, diagnostic tools and treatment options.
International Nuclear Information System (INIS)
Zangana, Abdulqadir M.; Razak, Awodan B.
2007-01-01
We report a giant testicular in a 36-year-old farmer man, of 18-month duration admitted to the Surgical Department Erbil Teaching Hospital, Iraq. The tumor was invading the penis and lower part of abdominal wall including bilateral groin lymph nodes. Histological examination revealed mature and immature teratoma. Further investigations showed no evidence of any metastatic lesions apart from a solitary pulmonary nodule on the right side of the chest which proved by ultra sonic guide fine needle aspiration biopsy. Radical excisions of the tumor including the shaft of the penis, combined with bilateral block dissection of the inguinal nodes and resection of the lower anterior abdominal wall was performed. Six weeks later after a course of chemotherapy and radiotherapy, the patient underwent resection of metastatic lung lesion. (author)
Self-induced light trapping in nonlinear Fabry–Perot resonators
Energy Technology Data Exchange (ETDEWEB)
Pichugin, K.N., E-mail: knp@tnp.krasn.ru; Sadreev, A.F., E-mail: almas@tnp.krasn.ru
2016-10-14
In the framework of the coupled mode theory we consider light trapping between two off-channel resonators which serve as self-adjusted Fano mirrors due to the Kerr effect. By inserting an auxiliary nonlinear resonator between the mirrors we achieve self-tuning of phase shift between the mirrors. That allows for the light trapping for arbitrary distance between the mirrors. - Highlights: • Fabry–Perot resonator traps light in a self-induced way if nonlinear cavity is inserted between mirrors.
Computation of Nonlinear Backscattering Using a High-Order Numerical Method
Fibich, G.; Ilan, B.; Tsynkov, S.
2001-01-01
The nonlinear Schrodinger equation (NLS) is the standard model for propagation of intense laser beams in Kerr media. The NLS is derived from the nonlinear Helmholtz equation (NLH) by employing the paraxial approximation and neglecting the backscattered waves. In this study we use a fourth-order finite-difference method supplemented by special two-way artificial boundary conditions (ABCs) to solve the NLH as a boundary value problem. Our numerical methodology allows for a direct comparison of the NLH and NLS models and for an accurate quantitative assessment of the backscattered signal.
Novitsky, Denis V.
2015-10-01
We use numerical simulations to study interaction of co- and counter-propagating pulses in disordered multilayers with noninstantaneous Kerr nonlinearity. We propose a statistical argument for existence of the disorder-induced trapping which implies the dramatic rise of the probability of realization with low output energy in the structure with a certain level of disorder. This effect is much more pronounced in the case of two interacting pulses than in the single-pulse regime and does not occur in the strictly ordered system at the same intensity of the pulses. Therefore it cannot be explained simply as a result of increase in strength of nonlinear light-matter interaction.
A mirror based polar magneto-optical Kerr effect spectroscopy arrangement.
Arora, Ashish; Ghosh, Sandip; Sugunakar, Vasam
2011-12-01
An arrangement is described for performing magneto-optical Kerr effect (MOKE) spectroscopy in polar geometry with a conventional C-frame or H-frame type electromagnet. It uses an additional mirror which eliminates the need for an electromagnet pole piece with an axial hole and allows for easy switching between polar MOKE geometry and longitudinal or transverse MOKE geometries. A theoretical analysis of the photo-elastic modulation based detection scheme shows that the mirror causes a strong mixing of signals corresponding to Kerr rotation and ellipticity. The influence of the mirror is experimentally demonstrated and a procedure is given to correct for it. MOKE spectrum of nickel films obtained using this arrangement is shown to match with reports in the literature.
Homoclinic orbits around spinning black holes. I. Exact solution for the Kerr separatrix
International Nuclear Information System (INIS)
Levin, Janna; Perez-Giz, Gabe
2009-01-01
For equatorial Kerr orbits, we show that each separatrix between bound and plunging geodesics is a homoclinic orbit--an orbit that asymptotes to an energetically-bound, unstable circular orbit. We derive exact expressions for these trajectories in terms of elementary functions. We also clarify the formal connection between the separatrix and zoom-whirl orbits and show that, contrary to popular belief, zoom-whirl behavior is not intrinsically a near-separatrix phenomenon. This paper focuses on homoclinic behavior in physical space, while in a companion paper we paint the complementary phase space portrait. Although they refer to geodesic motion, the exact solutions for the Kerr separatrix could be useful for analytic or numerical studies of eccentric transitions from orbital to plunging motion under the dissipative effects of gravitational radiation.
Global embedding of the Kerr black hole event horizon into hyperbolic 3-space
International Nuclear Information System (INIS)
Gibbons, G. W.; Herdeiro, C. A. R.; Rebelo, C.
2009-01-01
An explicit global and unique isometric embedding into hyperbolic 3-space, H 3 , of an axi-symmetric 2-surface with Gaussian curvature bounded below is given. In particular, this allows the embedding into H 3 of surfaces of revolution having negative, but finite, Gaussian curvature at smooth fixed points of the U(1) isometry. As an example, we exhibit the global embedding of the Kerr-Newman event horizon into H 3 , for arbitrary values of the angular momentum. For this example, considering a quotient of H 3 by the Picard group, we show that the hyperbolic embedding fits in a fundamental domain of the group up to a slightly larger value of the angular momentum than the limit for which a global embedding into Euclidean 3-space is possible. An embedding of the double-Kerr event horizon is also presented, as an example of an embedding that cannot be made global.
Kerr-Taub-NUT General Frame, Energy, and Momentum in Teleparallel Equivalent of General Relativity
Directory of Open Access Journals (Sweden)
Gamal G. L. Nashed
2012-01-01
Full Text Available A new exact solution describing a general stationary and axisymmetric object of the gravitational field in the framework of teleparallel equivalent of general relativity (TEGR is derived. The solution is characterized by three parameters “the gravitational mass M, the rotation a, and the NUT L.” The vierbein field is axially symmetric, and the associated metric gives the Kerr-Taub-NUT spacetime. Calculation of the total energy using two different methods, the gravitational energy momentum and the Riemannian connection 1-form Γα̃β, is carried out. It is shown that the two methods give the same results of energy and momentum. The value of energy is shown to depend on the mass M and the NUT parameter L. If L is vanishing, then the total energy reduced to the energy of Kerr black hole.
Dynamic Magneto-Optical Kerr Imaging of Perpendicular Anisotropy Artificial Spin Ice Geometries
Fraleigh, Robert; Lammert, Paul; Crespi, Vin; Samarth, Nitin; Gilbert, Ian; Schiffer, Peter
2014-03-01
We present a spatially resolved magneto-optical Kerr imaging study on the magnetization reversal, as a function of applied field, of patterned arrays of perpendicular anisotropy single domain islands. Patterns are made of large collections of CoPt multilayer islands with frustrated (Kagome, triangular) and unfrustrated (square, hexagonal) geometries. Field induced switching is imaged with a Kerr imaging apparatus equipped with an objective lens that allows for diffraction limited spatial resolution as low as 250nm and imaging acquisition as fast as 12 frames/second. The magnetization reversal process is probed by varying lattice spacing, geometry, and artificial defects in the patterned arrays. Supported by the US Department of Energy, Office of Basic Energy Sciences, Materials Sciences and Engineering Division under grant number DE--SC0005313.
Classification of Kerr-de Sitter-like spacetimes with conformally flat \\mathscr{I}
Mars, Marc; Paetz, Tim-Torben; Senovilla, José M. M.
2017-05-01
We provide a classification of Λ >0 -vacuum spacetimes which admit a Killing vector field with respect to which the associated ‘Mars-Simon tensor’ (MST) vanishes and have a conformally flat {{\\mathscr{I}}-} (or {{\\mathscr{I}}+} ). To that end, we also give a complete classification of conformal Killing vector fields on the 3-sphere {{{S}}3} up to Möbius transformations shedding light on the two fundamental constants that characterize the family of Kerr-de Sitter-like spacetimes, which turn out to be well-defined geometrical invariants. The topology of \\mathscr{I} is determined in every case, and a characterization result at \\mathscr{I} of the Kerr-de Sitter family presented. Preprint UWThPh-2016-20.
Reconfigurable microwave photonic transversal filter based on an integrated Kerr comb
Xu, Xingyuan; Wu, Jiayang; Nguyen, Thach G.; Shoeiby, Mehrdad; Chu, Sai T.; Little, Brent E.; Morandotti, Roberto; Mitchell, Arnan; Moss, David J.
2018-01-01
A reconfigurable microwave photonic filter (MPF) based on an integrated Kerr comb source was proposed and demonstrated. By employing an on-chip micro-ring resonator (MRR), a broadband Kerr comb with a large number of comb lines was generated and used as a high-quality multi-wavelength source for the MPF, which greatly reduced the size and cost. The enhanced performance of the MPF was theoretically analysed and systematically characterized. Due to the large channel number and high reconfigurability of the scheme, the MPF features an improved Q factor and wideband tunability. The experimental results matches well with theory, verifying the feasibility of our approach as a solution towards implementing highly reconfigurable MPFs with reduced system complexity.
Fujii, Shun; Kato, Takumi; Suzuki, Ryo; Hori, Atsuhiro; Tanabe, Takasumi
2018-01-01
We theoretically and experimentally investigated the transition between modulation instability and Raman gain in a small silica microcavity with a large free-spectral range (FSR), which reveals that we can selectively switch from a four-wave mixing dominant state to a stimulated Raman scattering dominant state. Both the theoretical analysis and the experiment show that a Raman-dominant region is present between transitions of Kerr combs with different free-spectral range spacings. We can obtain a stable Kerr comb and a stable Raman state selectively by changing the driving power, coupling between the cavity and the waveguide, and laser detuning. Such a controllable transition is achieved thanks to the presence of gain competition between modulation instability and Raman gain in silica whispering gallery mode microcavities.
An observational criterion to look for an inspiral in a non-Kerr spacetime
Energy Technology Data Exchange (ETDEWEB)
Apostolatos, Theocharis A; Lukes-Gerakopoulos, Georgios; Deligiannis, John [Section of Astrophysics, Astronomy, and Mechanics, Department of Physics, University of Athens, Panepistimiopolis Zografos GR-15783, Athens (Greece); Contopoulos, George, E-mail: tapostol@cc.uoa.g [Academy of Athens, Research Center for Astronomy, Soranou Efesiou 4, GR-11527, Athens (Greece)
2009-10-01
In this short article we present a useful observational tool for gravitational wave detectors. More specifically, if we are looking for extreme-mass-ratio inspiraling objects in a non-Kerr spacetime, we could exploit the consequences of the KAM and the Poincare-Birkhoff theorem which predicts plateaus in the ratio of frequencies f{sub {rho}/}f{sub z}, that are related to a generic geodesic orbit in such a spacetime, as a function of the initial conditions of the orbit itself. While both these frequencies are changing under radiation reaction, their ratio is expected to stay stationary if it passes through such a plateau. Therefore, if detectors are able to discern the fundamental frequencies due to {rho} and z oscillations of the orbit, they could in principle detect the non-Kerr-ness of the spacetime involved, just by monitoring the ratio of these two frequencies.
The abnormal temperature profile of accreting disk around the Kerr black hole
International Nuclear Information System (INIS)
Zhang, J.; Jiang, S.
1983-01-01
In this paper, we used the more rigorous general relativistic viscous hydrodynamical equation to discuss and calculate the temperature profile in the accreting disk around a Kerr black hole. It is found that for an accreting disk around a Kerr black hole, the occurrence of extremum values in the temperature profile is indeed possible. Furthermore, the temperature profile is always the same - no matter what kind of viscous mechanism is adopted - if the radiative mechanism of the materials in the disk is black-body radiation. For free-free radiation, we adopted the so-called α-viscosity law model to get a solution analogous to that obtained earlier (Fang et al., 1980). The calculations show that there exists a fast cooling ring region lying just inside the temperature maximum. In this ring region, there are probably some pecularities which do not exist in the usual temperature profile calculation (Fang, 1981). (orig.)
Gravitational waves from extreme mass ratio inspirals in nonpure Kerr spacetimes
International Nuclear Information System (INIS)
Barausse, Enrico; Rezzolla, Luciano; Petroff, David; Ansorg, Marcus
2007-01-01
To investigate the imprint on the gravitational-wave emission from extreme mass ratio inspirals (EMRIs) in nonpure Kerr spacetimes, we have studied the kludge waveforms generated in highly accurate, numerically generated spacetimes containing a black hole and a self-gravitating, homogeneous torus with comparable mass and spin. In order to maximize their impact on the produced waveforms, we have considered tori that are compact, massive, and close to the central black hole, investigating under what conditions the LISA experiment could detect their presence. Our results show that for a large portion of the space of parameters the waveforms produced by EMRIs in these black hole-torus systems are indistinguishable from pure Kerr waveforms. Hence, a 'confusion problem' will be present for observations carried out over a time scale below or comparable to the dephasing time
Transfer matrix approach for the Kerr and Faraday rotation in layered nanostructures.
Széchenyi, Gábor; Vigh, Máté; Kormányos, Andor; Cserti, József
2016-09-21
To study the optical rotation of the polarization of light incident on multilayer systems consisting of atomically thin conductors and dielectric multilayers we present a general method based on transfer matrices. The transfer matrix of the atomically thin conducting layer is obtained using the Maxwell equations. We derive expressions for the Kerr (Faraday) rotation angle and for the ellipticity of the reflected (transmitted) light as a function of the incident angle and polarization of the light. The method is demonstrated by calculating the Kerr (Faraday) angle for bilayer graphene in the quantum anomalous Hall state placed on the top of dielectric multilayers. The optical conductivity of the bilayer graphene is calculated in the framework of a four-band model.
Transfer matrix approach for the Kerr and Faraday rotation in layered nanostructures
International Nuclear Information System (INIS)
Széchenyi, Gábor; Vigh, Máté; Cserti, József; Kormányos, Andor
2016-01-01
To study the optical rotation of the polarization of light incident on multilayer systems consisting of atomically thin conductors and dielectric multilayers we present a general method based on transfer matrices. The transfer matrix of the atomically thin conducting layer is obtained using the Maxwell equations. We derive expressions for the Kerr (Faraday) rotation angle and for the ellipticity of the reflected (transmitted) light as a function of the incident angle and polarization of the light. The method is demonstrated by calculating the Kerr (Faraday) angle for bilayer graphene in the quantum anomalous Hall state placed on the top of dielectric multilayers. The optical conductivity of the bilayer graphene is calculated in the framework of a four-band model. (paper)
Shadow casted by a Konoplya-Zhidenko rotating non-Kerr black hole
Energy Technology Data Exchange (ETDEWEB)
Wang, Mingzhi; Chen, Songbai; Jing, Jiliang, E-mail: wmz9085@126.com, E-mail: csb3752@hunnu.edu.cn, E-mail: jljing@hunnu.edu.cn [Institute of Physics and Department of Physics, Hunan Normal University, Changsha, Hunan 410081 (China)
2017-10-01
We have investigated the shadow of a Konoplya-Zhidenko rotating non-Kerr black hole with an extra deformation parameter. The spacetime structure arising from the deformed parameter affects sharply the black hole shadow. With the increase of the deformation parameter, the size of the shadow of black hole increase and its shape becomes more rounded for arbitrary rotation parameter. The D-shape shadow of black hole emerges only in the case a <2√3/3\\, M with the proper deformation parameter. Especially, the black hole shadow possesses a cusp shape with small eye lashes in the cases with a >M, and the shadow becomes less cuspidal with the increase of the deformation parameter. Our result show that the presence of the deformation parameter yields a series of significant patterns for the shadow casted by a Konoplya-Zhidenko rotating non-Kerr black hole.
Ruszczynski, Andrzej
2011-01-01
Optimization is one of the most important areas of modern applied mathematics, with applications in fields from engineering and economics to finance, statistics, management science, and medicine. While many books have addressed its various aspects, Nonlinear Optimization is the first comprehensive treatment that will allow graduate students and researchers to understand its modern ideas, principles, and methods within a reasonable time, but without sacrificing mathematical precision. Andrzej Ruszczynski, a leading expert in the optimization of nonlinear stochastic systems, integrates the theory and the methods of nonlinear optimization in a unified, clear, and mathematically rigorous fashion, with detailed and easy-to-follow proofs illustrated by numerous examples and figures. The book covers convex analysis, the theory of optimality conditions, duality theory, and numerical methods for solving unconstrained and constrained optimization problems. It addresses not only classical material but also modern top...
A Monte Carlo Code for Relativistic Radiation Transport Around Kerr Black Holes
Schnittman, Jeremy David; Krolik, Julian H.
2013-01-01
We present a new code for radiation transport around Kerr black holes, including arbitrary emission and absorption mechanisms, as well as electron scattering and polarization. The code is particularly useful for analyzing accretion flows made up of optically thick disks and optically thin coronae. We give a detailed description of the methods employed in the code and also present results from a number of numerical tests to assess its accuracy and convergence.
Onset of superradiant instabilities in the composed Kerr-black-hole–mirror bomb
Shahar Hod
2014-01-01
It was first pointed out by Press and Teukolsky that a system composed of a spinning Kerr black hole surrounded by a reflecting mirror may develop instabilities. The physical mechanism responsible for the development of these exponentially growing instabilities is the superradiant amplification of bosonic fields confined between the black hole and the mirror. A remarkable feature of this composed black-hole-mirror-field system is the existence of a critical mirror radius, $r^{\\text{stat}}_{\\t...
Improvement in spatial frequency characteristics of magneto-optical Kerr microscopy
Ogasawara, Takeshi
2017-10-01
The spatial resolution of a conventional magneto-optical Kerr microscope, compared with those of conventional optical microscopes, inevitably deteriorates owing to oblique illumination. An approach to obtaining the maximum spatial resolution using multiple images with different illumination directions is demonstrated here. The method was implemented by rotating the illumination path around the optical axis using a motorized stage. The Fourier transform image of the observed magnetic domain indicates that the spatial frequency component that is lost in the conventional method is restored.
Tortoise coordinate and Hawking effect in a dynamical Kerr black hole
Yang, Jian; Zhao, Zheng; Liu, Wenbiao
2011-02-01
Hawking effect from a dynamical Kerr black hole is investigated using the improved Damour-Ruffini method with a new tortoise coordinate transformation. Hawking temperature of the black hole can be obtained point by point at the event horizon. It is found that Hawking temperatures of different points on the surface are different. Moreover, the temperature does not turn to zero while the dynamical black hole turns to an extreme one.
Effects of resonator input power on Kerr lens mode-locked lasers
Indian Academy of Sciences (India)
Additionally, in order to simplify the article, a Gaussian beam is considered. Figure 1. Resonator configuration for KLM laser: tilted mirrors M2 and M3 are focussing; output mirror M1 and back mirror M4 are flat; S1 and S2 are the slits;. L1 and L2 are the arms. The Kerr medium is placed between the mirrors M2 and M3.
On the construction of a geometric invariant measuring the deviation from Kerr data
Bäckdahl, Thomas; Kroon, Juan A. Valiente
2010-01-01
This article contains a detailed and rigorous proof of the construction of a geometric invariant for initial data sets for the Einstein vacuum field equations. This geometric invariant vanishes if and only if the initial data set corresponds to data for the Kerr spacetime, and thus, it characterises this type of data. The construction presented is valid for boosted and non-boosted initial data sets which are, in a sense, asymptotically Schwarzschildean. As a preliminary step to the constructi...
Higher Dimensional Kerr-Schild Spacetimes with (A)dS Background
Czech Academy of Sciences Publication Activity Database
Málek, T.; Pravda, Vojtěch
2011-01-01
Roč. 314, - (2011), 012111 ISSN 1742-6588. [Spanish Relativity Meeting (ERE 2010). Granada, 06.09.2010-10.09.2010] R&D Projects: GA ČR GAP203/10/0749 Institutional research plan: CEZ:AV0Z10190503 Keywords : Kerr-Schild metrics * Einstein equations Subject RIV: BA - General Mathematics http://iopscience.iop.org/1742-6596/314/1/012111
Holographic description of Kerr-Bolt-AdS-dS spacetimes
International Nuclear Information System (INIS)
Chen, B.; Ghezelbash, A.M.; Kamali, V.; Setare, M.R.
2011-01-01
We show that there exists a holographic 2D CFT description of a Kerr-Bolt-AdS-dS spacetime. We first consider the wave equation of a massless scalar field propagating in extremal Kerr-Bolt-AdS-dS spacetimes and find in the 'near region', the wave equation in extremal limit could be written in terms of the SL(2,R) quadratic Casimir. This suggests that there exist dual CFT descriptions of these black holes. In the probe limit, we compute the scattering amplitudes of the scalar off the extremal black holes and find perfect agreement with the CFT prediction. Furthermore we study the holographic description of the generic four-dimensional non-extremal Kerr-Bolt-AdS-dS black holes. We find that if focusing on the near-horizon region, for the massless scalar scattering in the low-frequency limit, the radial equation could still be rewritten as the SL(2,R) quadratic Casimir, suggesting the existence of dual 2D description. We read the temperatures of the dual CFT from the conformal coordinates and obtain the central charges by studying the near-horizon geometry of near-extremal black holes. We recover the macroscopic entropy from the microscopic counting. We also show that for the super-radiant scattering, the retarded Green's functions and the corresponding absorption cross sections are in perfect match with CFT prediction.
Holographic description of Kerr-Bolt-AdS-dS spacetimes
Energy Technology Data Exchange (ETDEWEB)
Chen, B., E-mail: bchen01@pku.edu.c [Department of Physics, and State Key Laboratory of Nuclear Physics and Technology, and Center for High Energy Physics, Peking University, Beijing 100871 (China); Ghezelbash, A.M., E-mail: masoud.ghezelbash@usask.c [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada); Kamali, V., E-mail: vkamali1362@gmail.co [Department of Campus of Bijar, Kurdistan University, Bijar (Iran, Islamic Republic of); Setare, M.R., E-mail: rezakord@ipm.i [Department of Campus of Bijar, Kurdistan University, Bijar (Iran, Islamic Republic of)
2011-07-01
We show that there exists a holographic 2D CFT description of a Kerr-Bolt-AdS-dS spacetime. We first consider the wave equation of a massless scalar field propagating in extremal Kerr-Bolt-AdS-dS spacetimes and find in the 'near region', the wave equation in extremal limit could be written in terms of the SL(2,R) quadratic Casimir. This suggests that there exist dual CFT descriptions of these black holes. In the probe limit, we compute the scattering amplitudes of the scalar off the extremal black holes and find perfect agreement with the CFT prediction. Furthermore we study the holographic description of the generic four-dimensional non-extremal Kerr-Bolt-AdS-dS black holes. We find that if focusing on the near-horizon region, for the massless scalar scattering in the low-frequency limit, the radial equation could still be rewritten as the SL(2,R) quadratic Casimir, suggesting the existence of dual 2D description. We read the temperatures of the dual CFT from the conformal coordinates and obtain the central charges by studying the near-horizon geometry of near-extremal black holes. We recover the macroscopic entropy from the microscopic counting. We also show that for the super-radiant scattering, the retarded Green's functions and the corresponding absorption cross sections are in perfect match with CFT prediction.
Ghasemi, M.; Tavassoly, M. K.; Nourmandipour, A.
2017-12-01
In this paper, we investigate the possibility of entanglement swapping between two independent nonperfect cavities consisting of an atom with finite lifetime of atomic levels (as two independent sources of dissipation), which interacts with a quantized electromagnetic field in the presence of detuning and Kerr medium. In fact, there is no direct interaction between the two atoms, therefore, no entanglement exists between them. We use the Bell state measurement performed on the photons leaving the cavities to swap the entanglement stored between the atom-fields in each cavity into atom-atom. Our motivation comes from the fact that two-qubit entangled states are of great interest for quantum information science and technologies. We discuss the effect of the initial state of the system, the detuning parameter, the Kerr medium and the two dissipation sources on the swapped entanglement to atom-atom. We interestingly find that when the atomic decay rates and photonic leakages from the cavities are equal, our system behaves as an ideal system with no dissipation. Our results show that it is possible to create a long-living atom-atom maximally entangled state in the presence of Kerr effect and dissipation; we determine these conditions in detail and also establish the final atom-atom Bell state.
Tori sequences as remnants of multiple accreting periods of Kerr SMBHs
Pugliese, D.; Stuchlík, Z.
2018-03-01
Super-massive black holes (SMBHs) hosted in active galactic nuclei (AGNs) can be characterized by multi-accreting periods as the attractors interact with the environment during their life-time. These multi-accretion episodes should leave traces in the matter orbiting the attractor. Counterrotating and even misaligned structures orbiting around the SMBHs would be consequences of these episodes. Our task in this work is to consider situations where such accretions occur and to trace their remnants represented by several toroidal accreting fluids, corotating or counterrotating relative to the central Kerr attractor, and created in various regimes during the evolution of matter configurations around SMBHs. We focus particularly on the emergence of matter instabilities, i.e., tori collisions, accretion onto the central Kerr black hole, or creation of jet-like structures (proto-jets). Each orbiting configuration is governed by the general relativistic hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluid. We prove that sequences of configurations and hot points, where an instability occurs, characterize the Kerr SMBHs, depending mainly on their spin-mass ratios. The occurrence of tori accretion or collision are strongly constrained by the fluid rotation with respect to the central black hole and the relative rotation with respect to each other. Our investigation provides characteristic of attractors where traces of multi-accreting episodes can be found and observed.
Testing the Kerr Black Hole Hypothesis Using X-Ray Reflection Spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Bambi, Cosimo; Nampalliwar, Sourabh [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Cárdenas-Avendaño, Alejandro [Programa de Matemática, Fundación Universitaria Konrad Lorenz, 110231 Bogotá (Colombia); Dauser, Thomas [Remeis Observatory and ECAP, Universität Erlangen-Nürnberg, D-96049 Bamberg (Germany); García, Javier A., E-mail: bambi@fudan.edu.cn [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
2017-06-20
We present the first X-ray reflection model for testing the assumption that the metric of astrophysical black holes is described by the Kerr solution. We employ the formalism of the transfer function proposed by Cunningham. The calculations of the reflection spectrum of a thin accretion disk are split into two parts: the calculation of the transfer function and the calculation of the local spectrum at any emission point in the disk. The transfer function only depends on the background metric and takes into account all the relativistic effects (gravitational redshift, Doppler boosting, and light bending). Our code computes the transfer function for a spacetime described by the Johannsen metric and can easily be extended to any stationary, axisymmetric, and asymptotically flat spacetime. Transfer functions and single line shapes in the Kerr metric are compared to those calculated from existing codes to check that we reach the necessary accuracy. We also simulate some observations with NuSTAR and LAD/eXTP and fit the data with our new model to show the potential capabilities of current and future observations to constrain possible deviations from the Kerr metric.
Two-dimensional matter-wave solitons and vortices in competing cubic-quintic nonlinear lattices
Gao, Xuzhen; Zeng, Jianhua
2018-02-01
The nonlinear lattice — a new and nonlinear class of periodic potentials — was recently introduced to generate various nonlinear localized modes. Several attempts failed to stabilize two-dimensional (2D) solitons against their intrinsic critical collapse in Kerr media. Here, we provide a possibility for supporting 2D matter-wave solitons and vortices in an extended setting — the cubic and quintic model — by introducing another nonlinear lattice whose period is controllable and can be different from its cubic counterpart, to its quintic nonlinearity, therefore making a fully "nonlinear quasi-crystal". A variational approximation based on Gaussian ansatz is developed for the fundamental solitons and in particular, their stability exactly follows the inverted Vakhitov-Kolokolov stability criterion, whereas the vortex solitons are only studied by means of numerical methods. Stability regions for two types of localized mode — the fundamental and vortex solitons — are provided. A noteworthy feature of the localized solutions is that the vortex solitons are stable only when the period of the quintic nonlinear lattice is the same as the cubic one or when the quintic nonlinearity is constant, while the stable fundamental solitons can be created under looser conditions. Our physical setting (cubic-quintic model) is in the framework of the Gross-Pitaevskii equation or nonlinear Schrödinger equation, the predicted localized modes thus may be implemented in Bose-Einstein condensates and nonlinear optical media with tunable cubic and quintic nonlinearities.
Devi, Anita; De, Arijit K.
2017-08-01
Experimental evidence indicates that high-repetition-rate ultrafast pulsed excitation is more efficient in optical trapping of dielectric nanoparticles as compared with continuous-wave excitation at the same average power. The physics behind the different nature of force under these two excitation conditions remained deceptive until quite recently when it was theoretically explained, in the dipole limit, as a combined effect of (1) repetitive instantaneous momentum transfer and (2) optical Kerr nonlinearity. The role of optical Kerr effect was theoretically studied for larger dielectric spherical particles, in the ray optics limit, also. However, a theoretical underpinning is yet to be established as to whether the effect of optical nonlinearity is omnipresent across different particle sizes, which we investigate here. Using localized approximation of generalized Lorenz-Mie theory, we theoretically analyze the nature of force (and potential) and provide a detailed comparative discussion between this generalized scattering formulation with dipole scattering formulation for dielectric nanoparticles.
Directory of Open Access Journals (Sweden)
Yonghua Hu
2018-03-01
Full Text Available Near medium intense (NMI fringe is a kind of intense fringe which can be formed near Kerr medium in high-power laser beam propagation. The formation properties of NMI fringe and the relations between NMI fringe and related important parameters are systematically investigated. It is found that it is the co-existence of two wirelike phase-typed scatterers in the incident beam spot which is mainly responsible for the high intensity of NMI fringe. From the viewpoint of coherent superposition, the formation process of NMI fringe is analyzed, and the mechanism that NMI fringe is formed by the coherent superposition of the localized bright fringes in the exit field of Kerr medium slab is demonstrated. The fluctuations of NMI fringe properties with beam wavelength, scatterer spacing and object distance are studied, the coherence of NMI fringe are revealed, and the approximate periodicity of the appearance of remarkable NMI fringe for these parameters are obtained. Especially, it is found that the intensity of NMI fringe is very sensitive to scatterer spacing. Besides, the laws about how NMI fringe properties will be changed by the modulation properties of scatterers and the medium thickness are demonstrated. Keywords: High-power laser beam, Nonlinear propagation, Kerr medium, Small-scale scatterer, Nonlinear imaging
A re-examination of the life and work of A.F.G. Kerr and of his colleagues and friends
DEFF Research Database (Denmark)
Parnell, J. A. N.; Pilla, F.; Simpson, D. A.
2015-01-01
Arthur Francis George Kerr's life is reviewed and related to a previously published account. Kerr's collecting activity is analysed using an expanded version of the Thai Biogeography Group's database of collections. 8,666 of the total 48,970 collections are Kerr's and 3,178 are those of his...... of Thailand and surrounding countries and would form an unique record of the social history of early 20thC Thailand....
Giant high occipital encephalocele
Directory of Open Access Journals (Sweden)
Agrawal Amit
2016-03-01
Full Text Available Encephaloceles are rare embryological mesenchymal developmental anomalies resulting from inappropriate ossification in skull through with herniation of intracranial contents of the sac. Encephaloceles are classified based on location of the osseous defect and contents of sac. Convexity encephalocele with osseous defect in occipital bone is called occipital encephalocele. Giant occipital encephaloceles can be sometimes larger than the size of baby skull itself and they pose a great surgical challenge. Occipital encephaloceles (OE are further classified as high OE when defect is only in occipital bone above the foramen magnum, low OE when involving occipital bone and foramen magnum and occipito-cervical when there involvement of occipital bone, foramen magnum and posterior upper neural arches. Chiari III malformation can be associated with high or low occipital encephaloceles. Pre-operatively, it is essential to know the size of the sac, contents of the sac, relation to the adjacent structures, presence or absence of venous sinuses/vascular structures and osseous defect size. Sometimes it becomes imperative to perform both CT and MRI for the necessary information. Volume rendered CT images can depict the relation of osseous defect to foramen magnum and provide information about upper neural arches which is necessary in classifying these lesions.
2001-01-01
Their work goes on unseen, because they a hundred metres beneath your feet. But while the race against the clock to build the LHC has begun on the surface, teams underground are feverishly engaged to dismantle LEP and its experiments. Four months after the start of dismantling, the technical coordinators of the different experiments discuss the progress of work. Little men attack the giant ALEPH. The barrel and its two endcaps have been removed to the end of the cavern and stripped of their cables. The breaking up of the detector can now begin. At ALEPH, counting rooms removed all in one go Jean-Paul Fabre, technical coordinator at ALEPH:'After making safe the structure, the first step was to remove the wiring and cables. Some 210 cubic metres were brought out. Then the counting rooms all round the detector were taken out. They were brought up from the cavern all in one go, up through the shaft, which is 10 metres wide and 150 metres deep. They made it with 15 centimetres to spare. They have been emptied of...
Giant necrotic pituitary apoplexy.
Fanous, Andrew A; Quigley, Edward P; Chin, Steven S; Couldwell, William T
2013-10-01
Apoplexy of the pituitary gland is a rare complication of pituitary adenomas, involving hemorrhage with or without necrosis within the tumor. This condition may be either asymptomatic or may present with severe headache, visual impairment, ophthalmoplegia, and pituitary failure. Transsphenoidal surgery is the treatment of choice, and early intervention is usually required to ensure reversal of visual impairment. Reports of pituitary apoplectic lesions exceeding 60.0mm in diameter are very rare. A 39-year-old man with long-standing history of nasal congestion, decreased libido and infertility presented with a sudden onset of severe headache and diplopia. MRI of the head demonstrated a massive skull base lesion of 70.0 × 60.0 × 25.0mm, compatible with a giant pituitary macroadenoma. The lesion failed to enhance after administration of a contrast agent, suggesting complete necrotic apoplexy. Urgent surgical decompression was performed, and the lesion was resected via a transnasal transsphenoidal approach. Pathological analysis revealed evidence of necrotic pituitary apoplexy. At the 2 month follow-up, the patient had near-complete to complete resolution of his visual impairment. To the authors' knowledge, this report is unique as the patient demonstrated complete necrotic apoplexy and it underlines the diagnostic dilemma in such a case. Copyright © 2012 Elsevier Ltd. All rights reserved.
Optical response of two coupled optomechanical systems in the presence of nonlinear mediums
Asghari Nejad, A.; Askari, H. R.; Baghshahi, H. R.
2018-01-01
In this paper, we investigate response of a hybrid optomechanical system in different situations. This system is composed of two coupled optomechanical cavities, which one of them is filled with an optical parametric amplifier (OPA) and the other one encompasses a nonlinear Kerr medium. The Hamiltonian of the system is written in a rotating frame. The dynamics of the system is obtained by the quantum Langevin equations of motion in a steady state regime. The results show that the presence of OPA and the Kerr medium in the system can considerably change the behavior of both cavities. For this reason, we show that by choosing different values for the optical parameters of the system, one can switches the behaviors of the cavities between mono-, bi- and tristability. Also, we show that by changing the detunings of the cavities, one can obtain uncommon responses from the system. Furthermore, we show that it is possible to create proper optical multistability regions for both cavities.
Formation of the giant planets
Lissauer, Jack J.
2006-01-01
The observed properties of giant planets, models of their evolution and observations of protoplanetary disks provide constraints on the formation of gas giant planets. The four largest planets in our Solar System contain considerable quantities of hydrogen and helium, which could not have condensed into solid planetesimals within the protoplanetary disk. All three (transiting) extrasolar giant planets with well determined masses and radii also must contain substantial amounts of these light gases. Jupiter and Saturn are mostly hydrogen and helium, but have larger abundances of heavier elements than does the Sun. Neptune and Uranus are primarily composed of heavier elements. HD 149026 b, which is slightly more massive than is Saturn, appears to have comparable quantities of light gases and heavy elements. HD 209458 b and TrES-1 are primarily hydrogen and helium, but may contain supersolar abundances of heavy elements. Spacecraft flybys and observations of satellite orbits provide estimates of the gravitational moments of the giant planets in our Solar System, which in turn provide information on the internal distribution of matter within Jupiter, Saturn, Uranus and Neptune. Atmospheric thermal structure and heat flow measurements constrain the interior temperatures of planets. Internal processes may cause giant planets to become more compositionally differentiated or alternatively more homogeneous; high-pressure laboratory .experiments provide data useful for modeling these processes. The preponderance of evidence supports the core nucleated gas accretion model. According to this model, giant planets begin their growth by the accumulation of small solid bodies, as do terrestrial planets. However, unlike terrestrial planets, the growing giant planet cores become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. The primary questions regarding the core nucleated growth model is under what conditions
Ulku, Huseyin Arda
2015-02-01
An explicit marching on-in-time (MOT) based time domain electric field volume integral equation (TDVIE) solver for characterizing electromagnetic wave interactions on scatterers with nonlinear material properties is proposed. Discretization of the unknown electric field intensity and flux density is carried out by half and full Schaubert-Wilton-Glisson basis functions, respectively. Coupled system of spatially discretized TDVIE and the nonlinear constitutive relation between the field intensity and the flux density is integrated in time to compute the samples of the unknowns. An explicit PE(CE)m scheme is used for this purpose. Explicitness allows for \\'easy\\' incorporation of the nonlinearity as a function only to be evaluated on the right hand side of the coupled system of equations. A numerical example that demonstrates the applicability of the proposed MOT scheme to analyzing electromagnetic interactions on Kerr-nonlinear scatterers is presented. © 2015 IEEE.
Dovgiy, A. A.
2014-12-01
The modulation instability is analytically investigated in a zigzag array of tunnel-coupled optical waveguides with alternating refractive indices and Kerr nonlinearity. Particular solutions to a system of coupled nonlinear equations are found. They describe the propagation of electromagnetic waves that are uniform along the waveguide and their instability is studied. It is shown that the coupling coefficient between the waveguides, which are non-nearest neighbours, has a significant effect on the instability of the waves in question. When the coupling coefficient exceeds a certain threshold, the modulation instability disappears regardless of the radiation power. The influence of the ratio of the wave amplitudes in adjacent waveguides to the instability of the particular solutions is studied. Different variants of the nonlinear response in waveguides are considered. The studies performed present a new unusual type of the modulation instability in nonlinear periodic systems.
Energy Technology Data Exchange (ETDEWEB)
Dovgiy, A A [National Research Nuclear University ' ' MEPhI' ' (Russian Federation)
2014-12-31
The modulation instability is analytically investigated in a zigzag array of tunnel-coupled optical waveguides with alternating refractive indices and Kerr nonlinearity. Particular solutions to a system of coupled nonlinear equations are found. They describe the propagation of electromagnetic waves that are uniform along the waveguide and their instability is studied. It is shown that the coupling coefficient between the waveguides, which are non-nearest neighbours, has a significant effect on the instability of the waves in question. When the coupling coefficient exceeds a certain threshold, the modulation instability disappears regardless of the radiation power. The influence of the ratio of the wave amplitudes in adjacent waveguides to the instability of the particular solutions is studied. Different variants of the nonlinear response in waveguides are considered. The studies performed present a new unusual type of the modulation instability in nonlinear periodic systems. (metamaterials)
Interaction of few-cycle laser pulses in an isotropic nonlinear medium
International Nuclear Information System (INIS)
Oganesyan, D L; Vardanyan, A O
2007-01-01
The interaction of few-cycle laser pulses propagating in an isotropic nonlinear medium is studied theoretically. A system of nonlinear Maxwell's equations is integrated numerically with respect to time by the finite difference method. The interaction of mutually orthogonal linearly polarised 0.81-μm, 10-fs pulses is considered. Both the instant Kerr polarisation response and Raman inertial response of the medium in the nonlinear part of the medium are taken into account. The spectral shift of the probe pulse caused by the cross-action of the reference pulse is studied. The spectra of the interacting pulses are studied for different time delays between them and the shifts of these spectra are obtained as a function of the time delay. (nonlinear optical phenomena)
Directory of Open Access Journals (Sweden)
C. Torres-Torres
2012-01-01
Full Text Available We report the transmittance modulation of optical signals in a nanocomposite integrated by two different silver doped zinc oxide thin solid films. An ultrasonic spray pyrolysis approach was employed for the preparation of the samples. Measurements of the third-order nonlinear optical response at a nonresonant 532 nm wavelength of excitation were performed using a vectorial two-wave mixing. It seems that the separated contribution of the optical nonlinearity associated with each film noticeable differs in the resulting nonlinear effects with respect to the additive response exhibited by the bilayer system. An enhancement of the optical Kerr nonlinearity is predicted for prime number arrays of the studied nanoclusters in a two-wave interaction. We consider that the nanostructured morphology of the thin solid films originates a strong modification of the third-order optical phenomena exhibited by multilayer films based on zinc oxide.
International Nuclear Information System (INIS)
Perri, F.
1975-01-01
When a planetary core composed of condensed matter is accumulated in the primitive solar nebula, the gas of the nebula becomes gravitationally concentrated as an envelope surrounding the planetary core. Models of such gaseous envelopes have been constructed subject to the assumption that the gas everywhere is on the same adiabat as that in the surrounding nebula. The gaseous envelope extends from the surface of the core to the distance at which the gravitational attraction of core plus envelope becomes equal to the gradient of the gravitational potential in the solar nebula; at this point the pressure and temperature of the gas in the envelope are required to attain the background values characteristic of the solar nebula. In general, as the mass of the condensed core increases, increasing amounts of gas became concentrated in the envelope, and these envelopes are stable against hydrodynamic instabilities. However, the core mass then goes through a maximum and starts to decrease. In most of the models tested the envelopes were hydrodynamically unstable beyond the peak in the core mass. An unstable situation was always created if it was insisted that the core mass contain a larger amount of matter than given by these solutions. For an initial adiabat characterized by a temperature of 450 0 K and a pressure of 5 x 10 -6 atmospheres, the maximum core mass at which instability occurs is approximately 115 earth masses. It is concluded that the giant planets obtained their large amounts of hydrogen and helium by a hydrodynamic collapse process in the solar nebula only after the nebula had been subjected to a considerable period of cooling
Directory of Open Access Journals (Sweden)
A. R. McGurn
2007-01-01
a number of analytical results are presented providing simple explanations of the quantitative behaviors of the systems. A relationship of these systems to forms of electromagnetic-induced transparency and modifications of waveguide dispersion relations is discussed.
Giant lobelias exemplify convergent evolution
Directory of Open Access Journals (Sweden)
Givnish Thomas J
2010-01-01
Full Text Available Abstract Giant lobeliads on tropical mountains in East Africa and Hawaii have highly unusual, giant-rosette growth forms that appear to be convergent on each other and on those of several independently evolved groups of Asteraceae and other families. A recent phylogenetic analysis by Antonelli, based on sequencing the widest selection of lobeliads to date, raises doubts about this paradigmatic example of convergent evolution. Here I address the kinds of evidence needed to test for convergent evolution and argue that the analysis by Antonelli fails on four points. Antonelli's analysis makes several important contributions to our understanding of lobeliad evolution and geographic spread, but his claim regarding convergence appears to be invalid. Giant lobeliads in Hawaii and Africa represent paradigmatic examples of convergent evolution.
Post-closure permit application for the Kerr Hollow Quarry at the Y-12 plant
International Nuclear Information System (INIS)
1995-06-01
The Kerr Hollow Quarry (KHQ) is located on U.S. Department of Energy (DOE) property at the Y-12 Plant, Oak Ridge, Tennessee. The Oak Ridge Y-12 Plant was built by the U.S. Army Corps of Engineers in 1943 as part of the Manhattan Project. Until 1992, the primary mission of the Y-12 Plant was the production and fabrication of nuclear weapons components. Activities associated with these functions included production of lithium compounds, recovery of enriched uranium from scrap material, and fabrication of uranium and other materials into finished parts for assemblies. The Kerr Hollow Quarry was used for waste disposal of a variety of materials including water-reactive and shock-sensitive chemicals and compressed gas cylinders. These materials were packaged in various containers and sank under the water in the quarry due to their great weight. Disposal activities were terminated in November, 1988 due to a determination by the Tennessee Department of Environment and Conservation that the quarry was subject to regulations under the Resource Conservation and Recovery Act of 1993. Methods of closure for the quarry were reviewed, and actions were initiated to close the quarry in accordance with closure requirements for interim status surface impoundments specified in Tennessee Rules 1200-1-11-.05(7) and 1200-1-11-.05(11). As part of these actions, efforts were made to characterize the physical and chemical nature of wastes that had been disposed of in the quarry, and to remove any containers or debris that were put into the quarry during waste disposal activities. Closure certification reports (Fraser et al. 1993 and Dames and Moore 1993) document closure activities in detail. This report contains the post-closure permit application for the Kerr Hollow Quarry site
Directory of Open Access Journals (Sweden)
Jung Hojoong
2016-06-01
Full Text Available A number of dielectric materials have been employed for on-chip frequency comb generation. Silicon based dielectrics such as silicon dioxide (SiO2 and silicon nitride (SiN are particularly attractive comb materials due to their low optical loss and maturity in nanofabrication. They offer third-order Kerr nonlinearity (χ(3, but little second-order Pockels (χ(2 effect. Materials possessing both strong χ(2 and χ(3 are desired to enable selfreferenced frequency combs and active control of comb generation. In this review, we introduce another CMOS-compatible comb material, aluminum nitride (AlN,which offers both second and third order nonlinearities. A review of the advantages of AlN as linear and nonlinear optical material will be provided, and fabrication techniques of low loss AlN waveguides from the visible to infrared (IR region will be discussed.We will then show the frequency comb generation including IR, red, and green combs in high-Q AlN micro-rings from single CW IR laser input via combination of Kerr and Pockels nonlinearity. Finally, the fast speed on-off switching of frequency comb using the Pockels effect of AlN will be shown,which further enriches the applications of the frequency comb.
Dispersion of nonresonant third-order nonlinearities in GeSiSn ternary alloys.
De Leonardis, Francesco; Troia, Benedetto; Soref, Richard A; Passaro, Vittorio M N
2016-09-13
Silicon (Si), tin (Sn), and germanium (Ge) alloys have attracted research attention as direct band gap semiconductors with applications in electronics and optoelectronics. In particular, GeSn field effect transistors can exhibit very high performance in terms of power reduction and operating speed because of the high electron drift mobility, while the SiGeSn system can be constructed using CMOS-compatible techniques to realize lasers, LED, and photodetectors. The wide Si, Ge and Sn transparencies allow the use of binary and ternary alloys extended to mid-IR wavelengths, where nonlinearities can also be employed. However, neither theoretical or experimental predictions of nonlinear features in SiGeSn alloys are reported in the literature. For the first time, a rigorous and detailed physical investigation is presented to estimate the two photon absorption (TPA) coefficient and the Kerr refractive index for the SiGeSn alloy up to 12 μm. The TPA spectrum, the effective TPA wavelength cut-off, and the Kerr nonlinear refractive index have been determined as a function of alloy compositions. The promising results achieved can pave the way to the demonstration of on-chip nonlinear-based applications, including mid-IR spectrometer-on-a-chip, all-optical wavelength down/up-conversion, frequency comb generation, quantum-correlated photon-pair source generation and supercontinuum source creation, as well as Raman lasing.
Control of polarization rotation in nonlinear propagation of fully structured light
Gibson, Christopher J.; Bevington, Patrick; Oppo, Gian-Luca; Yao, Alison M.
2018-03-01
Knowing and controlling the spatial polarization distribution of a beam is of importance in applications such as optical tweezing, imaging, material processing, and communications. Here we show how the polarization distribution is affected by both linear and nonlinear (self-focusing) propagation. We derive an analytical expression for the polarization rotation of fully structured light (FSL) beams during linear propagation and show that the observed rotation is due entirely to the difference in Gouy phase between the two eigenmodes comprising the FSL beams, in excellent agreement with numerical simulations. We also explore the effect of cross-phase modulation due to a self-focusing (Kerr) nonlinearity and show that polarization rotation can be controlled by changing the eigenmodes of the superposition, and physical parameters such as the beam size, the amount of Kerr nonlinearity, and the input power. Finally, we show that by biasing cylindrical vector beams to have elliptical polarization, we can vary the polarization state from radial through spiral to azimuthal using nonlinear propagation.
Hawking radiation screening and Penrose process shielding in the Kerr black hole
Energy Technology Data Exchange (ETDEWEB)
Mc Caughey, Eamon [Dublin Institute of Technology, School of Mathematical Sciences, Dublin 8 (Ireland)
2016-04-15
The radial motion of massive particles in the equatorial plane of a Kerr black hole is considered. Screening of the Hawking radiation and shielding of the Penrose process are examined (both inside and outside the ergosphere) and their effect on the evaporation of the black hole is studied. In particular, the locus and width of a classically forbidden region and their dependence on the particle's angular momentum and energy is analysed. Tunneling of particles between the boundaries of this region is considered and the transmission coefficient determined. (orig.)
High Performance Simulations of Accretion Disk Dynamics and Jet Formations Around Kerr Black Holes
Nishikawa, Ken-Ichi; Mizuno, Yosuke; Watson, Michael
2007-01-01
We investigate jet formation in black-hole systems using 3-D General Relativistic Particle-In-Cell (GRPIC) and 3-D GRMHD simulations. GRPIC simulations, which allow charge separations in a collisionless plasma, do not need to invoke the frozen condition as in GRMHD simulations. 3-D GRPIC simulations show that jets are launched from Kerr black holes as in 3-D GRMHD simulations, but jet formation in the two cases may not be identical. Comparative study of black hole systems with GRPIC and GRMHD simulations with the inclusion of radiate transfer will further clarify the mechanisms that drive the evolution of disk-jet systems.
Interferometric method to determine the Kerr constant of perspex and ZnSe
CSIR Research Space (South Africa)
Govender, P
2010-09-01
Full Text Available , (1999). [2] T. K. Ishii and A. Griffis, “Measurement of electro-optic effects in acrylic plastic”, Microwave and Optical Technology Letters, 4, 387-389(1991). [3] W. Kucharczyk, M. J. Gunning, R. E. Raab and C. Graham, “Interferometric investigation... to Determine the Kerr Constant of Perspex Patricia Govender1, 2, Dr. V.W. Couling1 1 UKZN Pietermaritzburg, King Edward Avenue, Scottsville, Pietermaritzburg 2 CSIR, DPSS, 3Meiring Naude Avenue Patricia Govender e-mail address: pgovender...
Energy Technology Data Exchange (ETDEWEB)
Lan, X.G. [Southwest Jiaotong University, Quantum Optoelectronics Laboratory, Chengdu (China); China West Normal University, Institute of Theoretical Physics, Nanchong (China); Jiang, Q.Q. [China West Normal University, Institute of Theoretical Physics, Nanchong (China); Wei, L.F. [Southwest Jiaotong University, Quantum Optoelectronics Laboratory, Chengdu (China); Sun Yat-Sen University, State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Guangzhou (China)
2012-04-15
We apply the Damour-Ruffini-Sannan method to study the Hawking radiations of scalar and Dirac particles in non-stationary Kerr black holes under different tortoise coordinate transformations. We found that all the relevant Hawking radiation spectra show still the blackbody ones, while the Hawking temperatures are strongly related to the used tortoise coordinate transformations. The properties of these dependences are discussed analytically and numerically. Our results imply that proper selections of tortoise coordinate transformations should be important in the studies of Hawking radiations and the correct selection would be given by the experimental observations in the future. (orig.)
Hawking radiation of Kerr-Newman black hole in different tortoise coordinate transformations
Ibungochouba Singh, T.
2013-10-01
Hawking radiation effect of Maxwell’s electromagnetic fields in the Kerr-Newman black hole space-time is investigated using two different tortoise coordinate transformations. It has been shown that the new tortoise coordinate transformation produces constant term ξ in the expression of surface gravity and Hawking temperature. If ξ is set to zero, the surface gravity and Hawking temperature will be equal to those obtained from the old tortoise coordinate transformation. This indicates that new transformation is more reliable and accurate. The black body radiant spectrum of photon displays a new spin-rotation coupling effect.
Lan, X. G.; Jiang, Q. Q.; Wei, L. F.
2012-04-01
We apply the Damour-Ruffini-Sannan method to study the Hawking radiations of scalar and Dirac particles in non-stationary Kerr black holes under different tortoise coordinate transformations. We found that all the relevant Hawking radiation spectra show still the blackbody ones, while the Hawking temperatures are strongly related to the used tortoise coordinate transformations. The properties of these dependences are discussed analytically and numerically. Our results imply that proper selections of tortoise coordinate transformations should be important in the studies of Hawking radiations and the correct selection would be given by the experimental observations in the future.
Hidden Symmetries of Euclideanised Kerr-NUT-(AdS Metrics in Certain Scaling Limits
Directory of Open Access Journals (Sweden)
Mihai Visinescu
2012-08-01
Full Text Available The hidden symmetries of higher dimensional Kerr-NUT-(AdS metrics are investigated. In certain scaling limits these metrics are related to the Einstein-Sasaki ones. The complete set of Killing-Yano tensors of the Einstein-Sasaki spaces are presented. For this purpose the Killing forms of the Calabi-Yau cone over the Einstein-Sasaki manifold are constructed. Two new Killing forms on Einstein-Sasaki manifolds are identified associated with the complex volume form of the cone manifolds. Finally the Killing forms on mixed 3-Sasaki manifolds are briefly described.
DEFF Research Database (Denmark)
Webb, Garry; Sørensen, Mads Peter; Brio, Moysey
2004-01-01
to circumvent this problem, non-canonical Poisson bracket formulations of the equations are obtained in which the electric field is one of the non-canonical variables. Noether's theorem, and the Lie point symmetries admitted by the equations are used to obtain four conservation laws, including......The vector Maxwell equations of nonlinear optics coupled to a single Lorentz oscillator and with instantaneous Kerr nonlinearity are investigated by using Lie symmetry group methods. Lagrangian and Hamiltonian formulations of the equations are obtained. The aim of the analysis is to explore...... the properties of Maxwell's equations in nonlinear optics, without resorting to the commonly used nonlinear Schr\\"odinger (NLS) equation approximation in which a high frequency carrier wave is modulated on long length and time scales due to nonlinear sideband wave interactions. This is important in femto...
Giant fields in southwest Mexico
Energy Technology Data Exchange (ETDEWEB)
1981-07-20
According to Petroleos Mexicanos southeastern Mexico's Isthmus Saline basin holds five new giant fields - Tonala-El Burro, El Plan, Cinco Presidentes, Oraggio, and Magallanes - producing oil and gas from Tertiary sandstones. Numerous normal faults resulting from salt intrusion have given rise to multiple blocks, each with its own reservoir conditions. Previously discovered basins in the area include the Macuspana, which holds three giant gas- and condensate-producing fields: Jose Colomo, Chilapilla, and Hormiquero. The 3100-mi/sup 2/ Campeche marine platform, extending offshore nearby, contains the Cantarell complex, Mexico's most productive hydrocarbon province.
Percolation with multiple giant clusters
International Nuclear Information System (INIS)
Ben-Naim, E; Krapivsky, P L
2005-01-01
We study mean-field percolation with freezing. Specifically, we consider cluster formation via two competing processes: irreversible aggregation and freezing. We find that when the freezing rate exceeds a certain threshold, the percolation transition is suppressed. Below this threshold, the system undergoes a series of percolation transitions with multiple giant clusters ('gels') formed. Giant clusters are not self-averaging as their total number and their sizes fluctuate from realization to realization. The size distribution F k , of frozen clusters of size k, has a universal tail, F k ∼ k -3 . We propose freezing as a practical mechanism for controlling the gel size. (letter to the editor)
Giant resonances: reaction theory approach
International Nuclear Information System (INIS)
Toledo Piza, A.F.R. de; Foglia, G.A.
1989-09-01
The study of giant resonances through the use of reaction theory approach is presented and discussed. Measurements of cross-sections to the many available decay channels following excitation of giant multipole resonances (GMR) led one to view these phenomena as complicated dynamical syndromes so that theoretical requirements for their study must be extended beyond the traditional bounds of nuclear structure models. The spectra of decay products following GMR excitation in heavy nuclei are well described by statistical model (Hauser-Feshback, HF) predictions indicated that spreading of the collective modes plays a major role in shaping exclusive cross-sections. (A.C.A.S.) [pt
Awakening a sleeping coal giant
Energy Technology Data Exchange (ETDEWEB)
Baxter, B.
2007-08-15
Botswana, a southern African country that in the 1980s could not economically land a tonne of coal at the closest export terminal and even today mines no more than 1 million tpa, is to increase production to beyond 30 million tpa. A first ever coal conference in Gaborone called it the awakening of a coal giant. The alarm call for the coal giant is the realisation that without more generating capacity than its power utility Eskom can itself build in time, South Africa will in four to five years face a severe shortage of power. 1 ref., 5 figs., 2 tabs.
2004-06-01
zero expansion asymptotically after an infinite time and has a flat geometry). All three observational tests by means of supernovae (green), the cosmic microwave background (blue) and galaxy clusters converge at a Universe around Ωm ~ 0.3 and ΩΛ ~ 0.7. The dark red region for the galaxy cluster determination corresponds to 95% certainty (2-sigma statistical deviation) when assuming good knowledge of all other cosmological parameters, and the light red region assumes a minimum knowledge. For the supernovae and WMAP results, the inner and outer regions corespond to 68% (1-sigma) and 95% certainty, respectively. References: Schuecker et al. 2003, A&A, 398, 867 (REFLEX); Tonry et al. 2003, ApJ, 594, 1 (supernovae); Riess et al. 2004, ApJ, 607, 665 (supernovae) Galaxy clusters are far from being evenly distributed in the Universe. Instead, they tend to conglomerate into even larger structures, "super-clusters". Thus, from stars which gather in galaxies, galaxies which congregate in clusters and clusters tying together in super-clusters, the Universe shows structuring on all scales, from the smallest to the largest ones. This is a relict of the very early (formation) epoch of the Universe, the so-called "inflationary" period. At that time, only a minuscule fraction of one second after the Big Bang, the tiny density fluctuations were amplified and over the eons, they gave birth to the much larger structures. Because of the link between the first fluctuations and the giant structures now observed, the unique REFLEX catalogue - the largest of its kind - allows astronomers to put considerable constraints on the content of the Universe, and in particular on the amount of dark matter that is believed to pervade it. Rather interestingly, these constraints are totally independent from all other methods so far used to assert the existence of dark matter, such as the study of very distant supernovae (see e.g. ESO PR 21/98) or the analysis of the Cosmic Microwave background (e
Giant gravitons-with strings attached (I)
International Nuclear Information System (INIS)
Mello Koch, Robert de; Smolic, Jelena; Smolic, Milena
2007-01-01
In this article, the free field theory limit of operators dual to giant gravitons with open strings attached, are studied. We introduce a graphical notation, which employs Young diagrams, for these operators. The computation of two point correlation functions is reduced to the application of three simple rules, written as graphical operations performed on the Young diagram labels of the operators. Using this technology, we have studied gravitational radiation by giant gravitons and bound states of giant gravitons, transitions between excited giant graviton states and joining of open strings attached to the giant
Pathogenesis of giant colonic diverticula
International Nuclear Information System (INIS)
Muhletaler, C.A.; Berger, J.L.; Robinette, C.L. Jr.
1981-01-01
The clinical, radiographic, and pathologic findings of 3 patients with giant colonic diverticula are presented. Although several theories have been proposed for the formation of these diverticula, they have not been fully documented. One of our cases illustrates the evolution of this disorder following typical colonic diverticulitis. The pathogenesis and differential diagnosis of this unusual entity are discussed. (orig.)
Giant resonances on excited states
International Nuclear Information System (INIS)
Besold, W.; Reinhard, P.G.; Toepffer, C.
1984-01-01
We derive modified RPA equations for small vibrations about excited states. The temperature dependence of collective excitations is examined. The formalism is applied to the ground state and the first excited state of 90 Zr in order to confirm a hypothesis which states that not only the ground state but every excited state of a nucleus has a giant resonance built upon it. (orig.)
Determination of giant resonance strengths
International Nuclear Information System (INIS)
Serr, F.E.
1983-01-01
Using theoretical strength functions to describe the different giant resonances expected at excitation energies of the order of (60-85)/Asup(1/3) MeV, we calculate the double differential cross sections d 2 sigma/dΩ dE associated with the reactions 208 Pb(α, α') and 90 Zr(α, α') (Esub(α) = 152 MeV). The angular distributions for the giant quadrupole and giant monopole resonances obtained from fits to these spectra, making simple, commonly used assumptions for the peak shapes and background, are compared to the original angular distributions. The differences between them are an indication of some of the uncertainties affecting the giant resonance strengths extracted from hadron inelastic scattering data. Fits to limited angular regions lead to errors of up to 50% in the value of the energy-weighted sum rule, depending on the angles examined. While it seems possible to extract the correct EWSR for the GMR by carrying out the analyses at 0 0 , no single privileged angle seems to exist in the case of the GQR. (orig.)
Brock, Raymond; Nichols, Sue
2007-01-01
"That giant is 750 miles of fiber optic cable that lassoes its three biggest research universities and Van Andel Institute to the future. Its mission: to uncover the nature of the Big Bang by connecton U.S. physicists to their huge experiment ATLAS in Geneva.." (4 pages)
DEFF Research Database (Denmark)
Schmid, Herman
2005-01-01
EU may appear to be a giant when it can act on behalf of a united Europe, but usually it is hampered by conflicting member state interests. The EU economic and administrative resources for foreign and trade policy are quite small (on level with one of its major member states) and the hopes in man...
Directory of Open Access Journals (Sweden)
Gokce Yildiran
2015-04-01
Conclusion: Giant lipomas of the hand are very rare and may cause compressions and other complications. Thus, they require a careful preoperative evaluation in order to make a proper differential diagnosis. [Hand Microsurg 2015; 4(1.000: 8-11
A note on physical mass and the thermodynamics of AdS-Kerr black holes
Energy Technology Data Exchange (ETDEWEB)
McInnes, Brett [Department of Mathematics, National University of Singapore, 10, Lower Kent Ridge Road, 119076 (Singapore); Ong, Yen Chin, E-mail: matmcinn@nus.edu.sg, E-mail: yenchin.ong@nordita.org [Nordic Institute for Theoretical Physics, KTH Royal Institute of Technology Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm (Sweden)
2015-11-01
As with any black hole, asymptotically anti-de Sitter Kerr black holes are described by a small number of parameters, including a ''mass parameter'' M that reduces to the AdS-Schwarzschild mass in the limit of vanishing angular momentum. In sharp contrast to the asymptotically flat case, the horizon area of such a black hole increases with the angular momentum parameter a if one fixes M; this appears to mean that the Penrose process in this case would violate the Second Law of black hole thermodynamics. We show that the correct procedure is to fix not M but rather the ''physical'' mass E=M/(1−a{sup 2}/L{sup 2}){sup 2}; this is motivated by the First Law. For then the horizon area decreases with a. We recommend that E always be used as the mass in physical processes: for example, in attempts to ''over-spin'' AdS-Kerr black holes.
Resonance spectrum of near-extremal Kerr black holes in the eikonal limit
International Nuclear Information System (INIS)
Hod, Shahar
2012-01-01
The fundamental resonances of rapidly rotating Kerr black holes in the eikonal limit are derived analytically. We show that there exists a critical value, μ c =√((15-√(193))/2 ), for the dimensionless ratio μ≡m/l between the azimuthal harmonic index m and the spheroidal harmonic index l of the perturbation mode, above which the perturbations become long lived. In particular, it is proved that above μ c the imaginary parts of the quasinormal frequencies scale like the black-hole temperature: ω I (n;μ>μ c )=2πT BH (n+1/2 ). This implies that for perturbations modes in the interval μ c I of the black hole becomes extremely long as the extremal limit T BH →0 is approached. A generalization of the results to the case of scalar quasinormal resonances of near-extremal Kerr-Newman black holes is also provided. In particular, we prove that only black holes that rotate fast enough (with MΩ≥2/5 , where M and Ω are the black-hole mass and angular velocity, respectively) possess this family of remarkably long-lived perturbation modes.
Polar Kerr effect studies of time reversal symmetry breaking states in heavy fermion superconductors
Energy Technology Data Exchange (ETDEWEB)
Schemm, E.R., E-mail: eschemm@alumni.stanford.edu [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Levenson-Falk, E.M. [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Department of Physics, Stanford University, Stanford, CA 94305 (United States); Kapitulnik, A. [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Department of Physics, Stanford University, Stanford, CA 94305 (United States); Department of Applied Physics, Stanford University, Stanford, CA 94305 (United States); Stanford Institute of Energy and Materials Science, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)
2017-04-15
Highlights: • Polar Kerr effect (PKE) probes broken time-reversal symmetry (TRS) in superconductors. • Absence of PKE below Tc in CeCoIn{sub 5} is consistent with dx2-y2 order parameter symmetry. • PKE in the B phase of the multiphase superconductor UPt3 agrees with an E2u model. • Data on URu2Si2 show broken TRS and additional structure in the superconducting state. - Abstract: The connection between chiral superconductivity and topological order has emerged as an active direction in research as more instances of both have been identified in condensed matter systems. With the notable exception of {sup 3}He-B, all of the known or suspected chiral – that is to say time-reversal symmetry-breaking (TRSB) – superfluids arise in heavy fermion superconductors, although the vast majority of heavy fermion superconductors preserve time-reversal symmetry. Here we review recent experimental efforts to identify TRSB states in heavy fermion systems via measurement of polar Kerr effect, which is a direct consequence of TRSB.
Gyromagnetic ratio of charged Kerr-anti-de Sitter black holes
International Nuclear Information System (INIS)
Aliev, Alikram N
2007-01-01
We examine the gyromagnetic ratios of rotating and charged AdS black holes in four and higher spacetime dimensions. We compute the gyromagnetic ratio for Kerr-AdS black holes with an arbitrary electric charge in four dimensions and show that it corresponds to g = 2 irrespective of the AdS nature of the spacetime. We also compute the gyromagnetic ratio for Kerr-AdS black holes with a single angular momentum and with a test electric charge in all higher dimensions. The gyromagnetic ratio crucially depends on the dimensionless ratio of the rotation parameter to the curvature radius of the AdS background. At the critical limit, when the boundary Einstein universe is rotating at the speed of light, it exhibits a striking feature leading to g 2 regardless of the spacetime dimension. Next, we extend our consideration to include the exact metric for five-dimensional rotating charged black holes in minimal gauged supergravity. We show that the value of the gyromagnetic ratio found in the 'test-charge' approach remains unchanged for these black holes
Onset of superradiant instabilities in the composed Kerr-black-hole–mirror bomb
Directory of Open Access Journals (Sweden)
Shahar Hod
2014-09-01
Full Text Available It was first pointed out by Press and Teukolsky that a system composed of a spinning Kerr black hole surrounded by a reflecting mirror may develop instabilities. The physical mechanism responsible for the development of these exponentially growing instabilities is the superradiant amplification of bosonic fields confined between the black hole and the mirror. A remarkable feature of this composed black-hole–mirror-field system is the existence of a critical mirror radius, rmstat, which supports stationary (marginally-stable field configurations. This critical (‘stationary’ mirror radius marks the boundary between stable and unstable black-hole–mirror-field configurations: composed systems whose confining mirror is situated in the region rmrmstat are unstable (that is, there are confined field modes which grow exponentially over time. In the present paper we explore this critical (marginally-stable boundary between stable and explosive black-hole–mirror-field configurations. It is shown that the innermost (smallest radius of the confining mirror which allows the extraction of rotational energy from a spinning Kerr black hole approaches the black-hole horizon radius in the extremal limit of rapidly-rotating black holes. We find, in particular, that this critical mirror radius (which marks the onset of superradiant instabilities in the composed system scales linearly with the black-hole temperature.
Spectroscopy of Kerr Black Holes with Earth- and Space-Based Interferometers.
Berti, Emanuele; Sesana, Alberto; Barausse, Enrico; Cardoso, Vitor; Belczynski, Krzysztof
2016-09-02
We estimate the potential of present and future interferometric gravitational-wave detectors to test the Kerr nature of black holes through "gravitational spectroscopy," i.e., the measurement of multiple quasinormal mode frequencies from the remnant of a black hole merger. Using population synthesis models of the formation and evolution of stellar-mass black hole binaries, we find that Voyager-class interferometers will be necessary to perform these tests. Gravitational spectroscopy in the local Universe may become routine with the Einstein Telescope, but a 40-km facility like Cosmic Explorer is necessary to go beyond z∼3. In contrast, detectors like eLISA (evolved Laser Interferometer Space Antenna) should carry out a few-or even hundreds-of these tests every year, depending on uncertainties in massive black hole formation models. Many space-based spectroscopical measurements will occur at high redshift, testing the strong gravity dynamics of Kerr black holes in domains where cosmological corrections to general relativity (if they occur in nature) must be significant.
The ergoregion in the Kerr spacetime: properties of the equatorial circular motion
Energy Technology Data Exchange (ETDEWEB)
Pugliese, D. [Silesian University in Opava, Faculty of Philosophy and Science, Institute of Physics, Opava (Czech Republic); Queen Mary University of London, School of Mathematical Sciences, London (United Kingdom); Quevedo, H. [Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, AP 70543, Mexico, DF (Mexico); Universita di Roma ' ' La Sapienza' ' , Dipartimento di Fisica, Roma (Italy)
2015-05-15
We investigate in detail the circular motion of test particles in the equatorial plane of the ergoregion in the Kerr spacetime. We consider all the regions where circular motion is allowed, and we analyze the stability properties and the energy and angular momentum of the test particles. We show that the structure of the stability regions has definite features that make it possible to distinguish between black holes and naked singularities. The naked singularity case presents a very structured non-connected set of regions of orbital stability, where the presence of counterrotating particles and zero angular momentum particles for a specific class of naked singularities is interpreted as due to the presence of a repulsive field generated by the central source of gravity. In particular, we analyze the effects of the dynamical structure of the ergoregion (the union of the orbital regions for different attractor spins) on the behavior of accretion disks around the central source. The properties of the circular motion turn out to be so distinctive that they allow for the introduction of a complete classification of Kerr spacetimes, each class of which is characterized by different physical effects that could be of especial relevance in observational astrophysics. We also identify some special black-hole spacetimes where these effects could be relevant. (orig.)
The ergoregion in the Kerr spacetime: properties of the equatorial circular motion
Pugliese, D.; Quevedo, H.
2015-05-01
We investigate in detail the circular motion of test particles in the equatorial plane of the ergoregion in the Kerr spacetime. We consider all the regions where circular motion is allowed, and we analyze the stability properties and the energy and angular momentum of the test particles. We show that the structure of the stability regions has definite features that make it possible to distinguish between black holes and naked singularities. The naked singularity case presents a very structured non-connected set of regions of orbital stability, where the presence of counterrotating particles and zero angular momentum particles for a specific class of naked singularities is interpreted as due to the presence of a repulsive field generated by the central source of gravity. In particular, we analyze the effects of the dynamical structure of the ergoregion (the union of the orbital regions for different attractor spins) on the behavior of accretion disks around the central source. The properties of the circular motion turn out to be so distinctive that they allow for the introduction of a complete classification of Kerr spacetimes, each class of which is characterized by different physical effects that could be of especial relevance in observational astrophysics. We also identify some special black-hole spacetimes where these effects could be relevant.
International Nuclear Information System (INIS)
Cardoso, Vitor; Lemos, Jose P.S.
2003-01-01
In this paper, we consider the gravitational radiation generated by the collision of highly relativistic particles with rotating Kerr black holes. We use the Sasaki-Nakamura formalism to compute the waveform, energy spectra, and total energy radiated during this process. We show that the gravitational spectrum for high-energy collisions has definite characteristic universal features, which are independent of the spin of the colliding objects. We also discuss the possible connections between these results and black-hole-black-hole collisions at the speed of light. Our results show that during the high-speed collision of a nonrotating hole with a rotating one, at most 35% of the total energy can get converted into gravitational waves. This 35% efficiency occurs only in the most optimistic situation, that of a zero impact parameter collision, along the equatorial plane, with an almost extreme Kerr black hole. In the general situation, the total gravitational energy radiated is expected to be much less, especially if the impact parameter increases. Thus, if one is able to produce black holes at the CERN Large Hadron Collider, at most 35% of the partons' energy should be emitted during the so-called balding phase. This energy will be missing, since we do not have gravitational wave detectors able to measure such amplitudes. The collision at the speed of light between one rotating black hole and a nonrotating one or two rotating black holes turns out to be the most efficient gravitational wave generator in the Universe
Decontamination and decommissioning of the Kerr-McGee Cimarron Plutonium Fuel Plant
Energy Technology Data Exchange (ETDEWEB)
1994-05-01
This final report is a summary of the events that completes the decontamination and decommissioning of the Cimarron Corporation`s Mixed Oxides Fuel Plant (formally Sequoyah Fuels Corporation and formerly Kerr-McGee Nuclear Corporation - all three wholly owned subsidiaries of the Kerr-McGee Corporation). Included are details dealing with tooling and procedures for performing the unique tasks of disassembly decontamination and/or disposal. That material which could not be economically decontaminated was volume reduced by disassembly and/or compacted for disposal. The contaminated waste cleaning solutions were processed through filtration and ion exchange for release or solidified with cement for L.S.A. waste disposal. The L.S.A. waste was compacted, and stabilized as required in drums for burial in an approved burial facility. T.R.U. waste packaging and shipping was completed by the end of July 1987. This material was shipped to the Hanford, Washington site for disposal. The personnel protection and monitoring measures and procedures are discussed along with the results of exposure data of operating personnel. The shipping containers for both T.R.U. and L.S.A. waste are described. The results of the decommissioning operations are reported in six reports. The personnel protection and monitoring measures and procedures are contained and discussed along with the results of exposure data of operating personnel in this final report.
Sagnac delay in the Kerr-dS spacetime: Implications for Mach's principle
Karimov, R. Kh.; Izmailov, R. N.; Garipova, G. M.; Nandi, K. K.
2018-02-01
Relativistic twin paradox can have important implications for Mach's principle. It has been recently argued that the behavior of the time asynchrony (different aging of twins) between two flying clocks along closed loops can be attributed to the existence of an absolute spacetime, which makes Mach's principle unfeasible. In this paper, we shall revisit, and support, this argument from a different viewpoint using the Sagnac delay. This is possible since the above time asynchrony is known to be exactly the same as the Sagnac delay between two circumnavigating light rays re-uniting at the orbiting source/receiver. We shall calculate the effect of mass M and cosmological constant Λ on the delay in the general case of Kerr-de Sitter spacetime. It follows that, in the independent limits M→ 0, spin a→ 0 and Λ → 0, while the Kerr-dS metric reduces to Minkowski metric, the clocks need not tick in consonance since there will still appear a non-zero observable Sagnac delay. While we do not measure spacetime itself, we do measure the Sagnac effect, which signifies an absolute substantive Minkowski spacetime instead of a void. We shall demonstrate a completely different limiting behavior of Sagnac delay, heretofore unknown, between the case of non-geodesic and geodesic source/observer motion.
On the Construction of a Geometric Invariant Measuring the Deviation from Kerr Data
Bäckdahl, Thomas; Valiente Kroon, Juan A.
2010-11-01
This article contains a detailed and rigorous proof of the construction of a geometric invariant for initial data sets for the Einstein vacuum field equations. This geometric invariant vanishes if and only if the initial data set corresponds to data for the Kerr spacetime, and thus, it characterises this type of data. The construction presented is valid for boosted and non-boosted initial data sets which are, in a sense, asymptotically Schwarzschildean. As a preliminary step to the construction of the geometric invariant, an analysis of a characterisation of the Kerr spacetime in terms of Killing spinors is carried out. A space spinor split of the (spacetime) Killing spinor equation is performed, to obtain a set of three conditions ensuring the existence of a Killing spinor of the development of the initial data set. In order to construct the geometric invariant, we introduce the notion of approximate Killing spinors. These spinors are symmetric valence 2 spinors intrinsic to the initial hypersurface and satisfy a certain second order elliptic equation ---the approximate Killing spinor equation. This equation arises as the Euler-Lagrange equation of a non-negative integral functional. This functional constitutes part of our geometric invariant ---however, the whole functional does not come from a variational principle. The asymptotic behaviour of solutions to the approximate Killing spinor equation is studied and an existence theorem is presented.
Higo, Tomoya; Man, Huiyuan; Gopman, Daniel B.; Wu, Liang; Koretsune, Takashi; van't Erve, Olaf M. J.; Kabanov, Yury P.; Rees, Dylan; Li, Yufan; Suzuki, Michi-To; Patankar, Shreyas; Ikhlas, Muhammad; Chien, C. L.; Arita, Ryotaro; Shull, Robert D.; Orenstein, Joseph; Nakatsuji, Satoru
2018-02-01
The magneto-optical Kerr effect (MOKE) has been intensively studied in a variety of ferro- and ferrimagnetic materials as a powerful probe for electronic and magnetic properties1-3 and for magneto-optical technologies4. The MOKE can be additionally useful for the investigation of the antiferromagnetic (AF) state, although thus far limited to insulators5-9. Here, we report the first observation of the MOKE in an AF metal. In particular, we find that the non-collinear AF metal Mn3Sn (ref. 10) exhibits a large zero-field Kerr rotation angle of 20 mdeg at room temperature, comparable to ferromagnetic metals. Our first-principles calculations clarify that ferroic ordering of magnetic octupoles11 produces a large MOKE even in its fully compensated AF state. This large MOKE further allows imaging of the magnetic octupole domains and their reversal. The observation of a large MOKE in an AF metal will open new avenues for the study of domain dynamics as well as spintronics using antiferromagnets12-16.
Rajasekar, Shanmuganathan
2016-01-01
This introductory text presents the basic aspects and most important features of various types of resonances and anti-resonances in dynamical systems. In particular, for each resonance, it covers the theoretical concepts, illustrates them with case studies, and reviews the available information on mechanisms, characterization, numerical simulations, experimental realizations, possible quantum analogues, applications and significant advances made over the years. Resonances are one of the most fundamental phenomena exhibited by nonlinear systems and refer to specific realizations of maximum response of a system due to the ability of that system to store and transfer energy received from an external forcing source. Resonances are of particular importance in physical, engineering and biological systems - they can prove to be advantageous in many applications, while leading to instability and even disasters in others. The book is self-contained, providing the details of mathematical derivations and techniques invo...
Numerical Simulations of Self-Focused Pulses Using the Nonlinear Maxwell Equations
Goorjian, Peter M.; Silberberg, Yaron; Kwak, Dochan (Technical Monitor)
1994-01-01
This paper will present results in computational nonlinear optics. An algorithm will be described that solves the full vector nonlinear Maxwell's equations exactly without the approximations that are currently made. Present methods solve a reduced scalar wave equation, namely the nonlinear Schrodinger equation, and neglect the optical carrier. Also, results will be shown of calculations of 2-D electromagnetic nonlinear waves computed by directly integrating in time the nonlinear vector Maxwell's equations. The results will include simulations of 'light bullet' like pulses. Here diffraction and dispersion will be counteracted by nonlinear effects. The time integration efficiently implements linear and nonlinear convolutions for the electric polarization, and can take into account such quantum effects as Kerr and Raman interactions. The present approach is robust and should permit modeling 2-D and 3-D optical soliton propagation, scattering, and switching directly from the full-vector Maxwell's equations. Abstract of a proposed paper for presentation at the meeting NONLINEAR OPTICS: Materials, Fundamentals, and Applications, Hyatt Regency Waikaloa, Waikaloa, Hawaii, July 24-29, 1994, Cosponsored by IEEE/Lasers and Electro-Optics Society and Optical Society of America
Effect of Kerr-like medium on a two-level atom in interaction with bimodal oscillator
Czech Academy of Sciences Publication Activity Database
Abdalla, M. S.; Křepelka, Jaromír; Peřina, Jan
2006-01-01
Roč. 39, - (2006), s. 1563-1577 ISSN 0953-4075 R&D Projects: GA MŠk(CZ) OC P11.003 Institutional research plan: CEZ:AV0Z10100522 Keywords : kerr-like medium * two-level atom * bimodal oscillator Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.024, year: 2006
The spinning Kerr-black-hole-mirror bomb: A lower bound on the radius of the reflecting mirror
Hod, Shahar
2016-10-01
The intriguing superradiant amplification phenomenon allows an orbiting scalar field to extract rotational energy from a spinning Kerr black hole. Interestingly, the energy extraction rate can grow exponentially in time if the black-hole-field system is placed inside a reflecting mirror which prevents the field from radiating its energy to infinity. This composed Kerr-black-hole-scalar-field-mirror system, first designed by Press and Teukolsky, has attracted the attention of physicists over the last four decades. Previous numerical studies of this spinning black-hole bomb have revealed the interesting fact that the superradiant instability shuts down if the reflecting mirror is placed too close to the black-hole horizon. In the present study we use analytical techniques to explore the superradiant instability regime of this composed Kerr-black-hole-linearized-scalar-field-mirror system. In particular, it is proved that the lower bound rm/r+ >1/2 (√{ 1 +8M/r- } - 1) provides a necessary condition for the development of the exponentially growing superradiant instabilities in this composed physical system, where rm is the radius of the confining mirror and r± are the horizon radii of the spinning Kerr black hole. We further show that, in the linearized regime, this analytically derived lower bound on the radius of the confining mirror agrees with direct numerical computations of the superradiant instability spectrum which characterizes the spinning black-hole-mirror bomb.
2010-04-01
... produce dental materials such as dental prosthetics, dental composites, dental impressions, dental... materials such as dental prosthetics, dental composites, dental impressions, dental adhesives, and other... Technologies, a Wholly-Owned Subsidiary of Kerr Dental/Sybron Dental Specialities, Formally Known as Customedix...
Czech Academy of Sciences Publication Activity Database
Životský, O.; Hendrych, A.; Klimša, L.; Jirásková, Yvonna; Buršík, Jiří; Gomez, J.A.M.; Janičkovič, D.
2012-01-01
Roč. 324, č. 4 (2012), s. 569-577 ISSN 0304-8853 Institutional research plan: CEZ:AV0Z20410507 Keywords : Surface magnetism * Magnetooptic Kerr effect * Magneto-optical microscopy * ILEEMS * CEMS * Nanoscale phase separation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.826, year: 2012
The spinning Kerr-black-hole-mirror bomb: A lower bound on the radius of the reflecting mirror
Directory of Open Access Journals (Sweden)
Shahar Hod
2016-10-01
Full Text Available The intriguing superradiant amplification phenomenon allows an orbiting scalar field to extract rotational energy from a spinning Kerr black hole. Interestingly, the energy extraction rate can grow exponentially in time if the black-hole-field system is placed inside a reflecting mirror which prevents the field from radiating its energy to infinity. This composed Kerr-black-hole-scalar-field-mirror system, first designed by Press and Teukolsky, has attracted the attention of physicists over the last four decades. Previous numerical studies of this spinning black-hole bomb have revealed the interesting fact that the superradiant instability shuts down if the reflecting mirror is placed too close to the black-hole horizon. In the present study we use analytical techniques to explore the superradiant instability regime of this composed Kerr-black-hole-linearized-scalar-field-mirror system. In particular, it is proved that the lower bound rmr+>12(1+8Mr−−1 provides a necessary condition for the development of the exponentially growing superradiant instabilities in this composed physical system, where rm is the radius of the confining mirror and r± are the horizon radii of the spinning Kerr black hole. We further show that, in the linearized regime, this analytically derived lower bound on the radius of the confining mirror agrees with direct numerical computations of the superradiant instability spectrum which characterizes the spinning black-hole-mirror bomb.
Energy Technology Data Exchange (ETDEWEB)
Nashed, Gamal G.L. [King Faisal University, Mathematics Department, Faculty of Science, Al-Ahsaa (Saudi Arabia); Ain Shams University, Mathematics Department, Faculty of Science, Cairo (Egypt); British University of Egypt, Center for Theoretical Physics, Sherouk City (Egypt)
2012-05-15
Total conserved charges of several axially symmetric tetrad spacetimes generating Kerr-NUT metric are calculated by using the approach of invariant conserved currents. Certain tetrads give the known values, while others give unusual charges and divergent quantities. Therefore, regularized expressions are employed to get the known form of conserved charges. (orig.)
Analytical Solitons for Langmuir Waves in Plasma Physics with Cubic Nonlinearity and Perturbations
Zhou, Qin; Mirzazadeh, M.
2016-09-01
We presented an analytical study on dynamics of solitons for Langmuir waves in plasma physics. The mathematical model is given by the perturbed nonlinear Schrödinger equation with full nonlinearity and Kerr law nonlinearity. There are three techniques of integrability were employed to extract exact solutions along with the integrability conditions. The topological 1-soliton solutions, singular 1-soliton solutions, and plane wave solution were reported by Ricatti equation expansion approach and then the bright 1-soliton solution, singular 1-soliton solution, periodic singular solutions, and plane wave solution were derived with the help of trial solution method. Finally, based on the G'/G-expansion scheme, we obtained the hyperbolic function travelling wave solution, trigonometric function travelling wave solution, and plane wave solution.
A nonlinear plasmonic resonator for three-state all-optical switching
Amin, Muhammad
2014-01-01
A nonlinear plasmonic resonator design is proposed for three-state all-optical switching at frequencies including near infrared and lower red parts of the spectrum. The tri-stable response required for three-state operation is obtained by enhancing nonlinearities of a Kerr medium through multiple (higher order) plasmons excited on resonator\\'s metallic surfaces. Indeed, simulations demonstrate that exploitation of multiple plasmons equips the proposed resonator with a multi-band tri-stable response, which cannot be obtained using existing nonlinear plasmonic devices that make use of single mode Lorentzian resonances. Multi-band three-state optical switching that can be realized using the proposed resonator has potential applications in optical communications and computing. © 2014 Optical Society of America.
Zhang, Junfeng; Chen, Wei; Gao, Mingyi; Shen, Gangxiang
2017-10-30
In this work, we proposed two k-means-clustering-based algorithms to mitigate the fiber nonlinearity for 64-quadrature amplitude modulation (64-QAM) signal, the training-sequence assisted k-means algorithm and the blind k-means algorithm. We experimentally demonstrated the proposed k-means-clustering-based fiber nonlinearity mitigation techniques in 75-Gb/s 64-QAM coherent optical communication system. The proposed algorithms have reduced clustering complexity and low data redundancy and they are able to quickly find appropriate initial centroids and select correctly the centroids of the clusters to obtain the global optimal solutions for large k value. We measured the bit-error-ratio (BER) performance of 64-QAM signal with different launched powers into the 50-km single mode fiber and the proposed techniques can greatly mitigate the signal impairments caused by the amplified spontaneous emission noise and the fiber Kerr nonlinearity and improve the BER performance.
An explicit MOT scheme for solving the TD-EFVIE on nonlinear and dispersive scatterers
Sayed, Sadeed Bin
2017-10-25
An explicit marching-on-in-time (MOT) scheme for solving the time domain electric field volume integral equation (TD-EFVIE) on nonlinear and dispersive scatterers is described. The unknown electric field intensity, electric flux density, and polarization densities representing Kerr nonlinearity along with Lorentz dispersion relation, all of which are induced inside the scatterer upon excitation, are expanded using half and full Schaubert-Wilton-Glisson functions in space. The TD-EFVIE and the constitutive relations between polarization, field, and flux terms are cast in the form of a first-order ordinary differential equation. The resulting matrix system is integrated in time using a predictor-corrector scheme to obtain the time dependent unknown expansion coefficients. The resulting MOT scheme is explicit and accounts for nonlinearity by simple function evaluations.
Multi-atom Jaynes-Cummings model with nonlinear effects
International Nuclear Information System (INIS)
Aleixo, Armando Nazareno Faria; Balantekin, Akif Baha; Ribeiro, Marco Antonio Candido
2001-01-01
The standard Jaynes-Cummings (JC) model and its extensions, normally used in quantum optics, idealizes the interaction of matter with electromagnetic radiation by a simple Hamiltonian of a two-level atom coupled to a single bosonic mode. This Hamiltonian has a fundamental importance to the field of quantum optics and it is a central ingredient in the quantized description of any optical system involving the interaction between light and atoms. The JC Hamiltonian defines a molecule, a composite system formed from the coupling of a two-state system and a quantized harmonic oscillator. For this Hamiltonian, mostly the single-particle situation has been studied. This model can also be extended for the situation where one has N two-level systems, which interact only with the electromagnetic radiation. In this case the effects of the spatial distribution of the particles it is not taken into account and the spin angular momentum S-circumflex i of each particle contributes to form a total angular momentum J-circumflex of the system. When one considers the effects due to the spatial variation in the field intensity in a nonlinear medium it is necessary to further add a Kerr term to the standard JC Hamiltonian. This kind of nonlinear JC Hamiltonian is used in the study of micro masers. Another nonlinear variant of the JC model takes the coupling between matter and the radiation to depend on the intensity of the electromagnetic field. This model is interesting since this kind of interaction means that effectively the coupling is proportional to the amplitude of the field representing a very simple case of a nonlinear interaction corresponding to a more realistic physical situation. In this work we solve exactly the problem of the interaction of a N two-level atoms with an electromagnetic radiation when nonlinear effects due to the spatial variation in the field intensity in a nonlinear Kerr medium and the dependence on the intensity of the electromagnetic field on the matter
[Nonlinear magnetohydrodynamics
International Nuclear Information System (INIS)
1994-01-01
Resistive MHD equilibrium, even for small resistivity, differs greatly from ideal equilibrium, as do the dynamical consequences of its instabilities. The requirement, imposed by Faraday's law, that time independent magnetic fields imply curl-free electric fields, greatly restricts the electric fields allowed inside a finite-resistivity plasma. If there is no flow and the implications of the Ohm's law are taken into account (and they need not be, for ideal equilibria), the electric field must equal the resistivity times the current density. The vanishing of the divergence of the current density then provides a partial differential equation which, together with boundary conditions, uniquely determines the scalar potential, the electric field, and the current density, for any given resistivity profile. The situation parallels closely that of driven shear flows in hydrodynamics, in that while dissipative steady states are somewhat more complex than ideal ones, there are vastly fewer of them to consider. Seen in this light, the vast majority of ideal MHD equilibria are just irrelevant, incapable of being set up in the first place. The steady state whose stability thresholds and nonlinear behavior needs to be investigated ceases to be an arbitrary ad hoc exercise dependent upon the whim of the investigator, but is determined by boundary conditions and choice of resistivity profile
Giant first-forbidden resonances
International Nuclear Information System (INIS)
Krmpotic, F.; Nakayama, K.; Sao Paulo Univ.; Pio Galeao, A.; Sao Paulo Univ.
1983-01-01
Recent experimental data on first-forbidden charge-exchange resonances are discussed in the framework of a schematic model. We also evaluate the screening of the weak coupling constants induced by both the giant resonances and the δ-isobar. It is shown that the last effect does not depend on the multipolarity of the one-particle moment. Due to the same reason, the fraction of the reaction strength pushed up into the δ-resonance region is always the same regardless of the quantum numbers carried by the excitation. Simple expressions are derived for the dependence of the excitation energies of the first-forbidden giant resonances on the mass number and isospin of the target. The model reproduces consistently both the Gamow-Teller and the first-forbidden resonances. (orig.)
Spinal cord giant arteriovenous fistulae
International Nuclear Information System (INIS)
Aymard, A.; Reizine, D.; Marciano, S.; Cervigon, E.G.; Gelbert, F.; Merland, J.J.
1988-01-01
Giant extramedullary arteriovenous fistulas fed by spinal arteries are a rare type of spinal cord arteriovenous malformation. Among 11 patient (mean age, 20 years) with spinal hemorrhage in childhood, progressive paraplegia, and myelographic and angiographic diagnosis, magnetic resonance imaging demonstrated the precised extramedulary location and complications (thrombosis 1). Angiography showed dilated spinal arteries feeding giant, high flow fistulas with much venous drainage. Endovascular treatment was performed in 11 cases, with balloons in seven, particulate embolization in three, and polymerizing agents in one. Complete closures of the shunt with clinical improvement was achieved in seven cases and partial closure with partial clinical recovery in two; there was one case each of paraplegia due to involuntary venous blockage by the balloon, and fatal bulbomedullary stroke in particulate embolization of cervical location. Careful endovascular techniques represent a valuable treatment in this severe pathology
Giant condyloma acuminatum of vulva
Directory of Open Access Journals (Sweden)
S. M. Ramiz Ahmed
2017-09-01
Full Text Available In this paper, A 23 year old married woman who was diagnosed as a case of giant condyloma acuminatum of vulva measuring about 15 x 8 x 3 cm, irregular surface with multiple projections, oval in shape, firm to hard in consistency, mildly tender, exophytic, cauliflower like growth involving the whole vulva (lower part of mons pubis, labia, vestibule, clitoris, around vaginal opening. Another multiple small lesions were present at perineal region but there was no inguinal lymphadenopathy. She underwent a combined electro cauterization and cryotherapy for small to moderate size multiple primary and recurrent warty lesions and wide surgical excision with fasciocutaneous advancement flaps procedure for a giant lesions in the vulva. Excisional biopsies were performed to detect potential malignancy but malignancy was not found histologically. The patient was advised to first follow-up 1 month after operation when multiple small warty lesions were developed and treated and the subsequent follow-ups for 3 months.
Sorce, Jonathan; Wald, Robert M.
2017-11-01
We consider gedanken experiments to destroy an extremal or nearly extremal Kerr-Newman black hole by causing it to absorb matter with sufficient charge and/or angular momentum as compared with energy that it cannot remain a black hole. It was previously shown by one of us that such gedanken experiments cannot succeed for test particle matter entering an extremal Kerr-Newman black hole. We generalize this result here to arbitrary matter entering an extremal Kerr-Newman black hole, provided only that the nonelectromagnetic contribution to the stress-energy tensor of the matter satisfies the null energy condition. We then analyze the gedanken experiments proposed by Hubeny and others to overcharge and/or overspin an initially slightly nonextremal Kerr-Newman black hole. Analysis of such gedanken experiments requires that we calculate all effects on the final mass of the black hole that are second-order in the charge and angular momentum carried into the black hole, including all self-force effects. We obtain a general formula for the full second order correction to mass, δ2M , which allows us to prove that no gedanken experiments of the generalized Hubeny type can ever succeed in overcharging and/or overspinning a Kerr-Newman black hole, provided only that the nonelectromagnetic stress-energy tensor satisfies the null energy condition. Our analysis is based upon Lagrangian methods, and our formula for the second-order correction to mass is obtained by generalizing the canonical energy analysis of Hollands and Wald to the Einstein-Maxwell case. Remarkably, we obtain our formula for δ2M without having to explicitly compute self-force or finite size effects. Indeed, in an appendix, we show explicitly that our formula incorporates both the self-force and finite size effects for the special case of a charged body slowly lowered into an uncharged black hole.
Giant Magnetoresistance in Nanogranular Magnets
Glatz, A.; Beloborodov, I. S.; Vinokur, V. M.
2007-01-01
We study the giant magnetoresistance of nanogranular magnets in the presence of an external magnetic field and finite temperature. We show that the magnetization of arrays of nanogranular magnets has hysteretic behaviour at low temperatures leading to a double peak in the magnetoresistance which coalesces at high temperatures into a single peak. We numerically calculate the magnetization of magnetic domains and the motion of domain walls in this system using a combined mean-field approach and...
Giant thermoelectric effect in graphene
Dragoman, D.; Dragoman, M.
2007-11-01
The paper predicts a giant thermoelectric coefficient in a nanostructure consisting of metallic electrodes periodically patterned over graphene, which is deposited on a silicon dioxide substrate. The Seebeck coefficient in this device attains 30mV/K, this value being among the largest reported ever. The calculations are based on a transfer matrix approach that takes a particular form for graphene-based devices. The results are important for future nanogenerators with applications in the area of sensors, energy harvesting, and scavenging.
Giant pediatric cervicofacial lymphatic malformations.
Benazzou, Salma; Boulaadas, Malik; Essakalli, Leila
2013-07-01
Lymphatic malformations (LMs) are benign lesions. Most of them are found in head and neck regions as asymptomatic mass, but giant lymphangiomas may affect breathing or swallowing and constitute a major therapeutic challenge. A retrospective analysis of giant head and neck LMs with impairment of respiration or swallow for the past 11 years was performed in the Department of Maxillofacial Surgery and ENT of the Avicenne Medical University Center. Seven patients with large and extensive LMs of the head and neck were identified. There were 3 males and 4 females with a mean age of 6 years. The predominant reason for referral was airway compromise necessitating tracheostomy (57%) and dysphagia (43%). Three patients had macrocystic lesions; others were considered mixed or microcystic. All the patients underwent surgical excision as a primary treatment modality. Complete surgical resection was realized in 4 patients, and subtotal resection in 3 patients. Of 7 patients, 4 patients had complications including nerve damage and recurrence of the disease. The majority of the patients underwent only a single surgical procedure. Cervicofacial LMs in children should be managed in multidisciplinary setting. Surgery remains the first treatment for managing giant, life-threatening lesions.
1998-08-01
New ESO Survey Provides Targets for the VLT Giant astronomical telescopes like the ESO Very Large Telescope (VLT) must be used efficiently. Observing time is expensive and there are long waiting lines of excellent research programmes. Thus the work at the telescope must be very well prepared and optimized as much as possible - mistakes should be avoided and no time lost! Astronomers working with the new 8-m class optical/infrared telescopes must base their observations on detailed lists of suitable target objects if they want to perform cutting-edge science. This is particularly true for research programmes that depend on observations of large samples of comparatively rare, distant objects. This type of work requires that extensive catalogues of such objects must be prepared in advance. One such major catalogue - that will serve as a very useful basis for future VLT observations - has just become available from the new ESO Imaging Survey (EIS). The Need for Sky Surveys Astronomers have since long recognized the need to carry out preparatory observations with other telescopes in order to "guide" large telescopes. To this end, surveys of smaller or larger parts of the sky have been performed by wide-field telescopes, paving the way for subsequent work at the limits of the largest available ground-based telescopes. For instance, a complete photographic survey of the sourthern sky (declination project is known as the ESO Imaging Survey (EIS). It is supervised by a Working Group with members from the European astronomical community ( [1]) that has been responsible for defining the survey strategy and for monitoring the progress. It has been a major challenge to carry out such a public survey in the very short time available. The work by the EIS Team has involved the survey observations at the NTT, development of a pipeline to process the raw data, advanced data reduction, identification of large samples of astronomically "interesting" targets and, not least, the
Dinamica do modelo de Jaynes-Cummings com meio Kerr e diferentes dessintonias
Pablo Parmezani Munhoz
2002-01-01
Resumo: Neste trabalho, apresentamos um estudo teórico da interação da radiação com a matéria. Investigamos a dinâmica do modelo de Jaynes-Cummings com um meio não-linear tipo Kerr, com-parando a situação de grande dessintonia átomo-campo com a evolução correspondente obtida de um Hamiltoniano efetivo (aproximação dispersiva). Para isto, obtemos o operador evolução para o sistema átomo-campo, que facilita considerar diferentes situações iniciais para o ´ atomo e o campo. Iniciamos nossa anál...
Time-resolved scanning Kerr microscopy of flux beam formation in hard disk write heads
International Nuclear Information System (INIS)
Valkass, Robert A. J.; Spicer, Timothy M.; Burgos Parra, Erick; Hicken, Robert J.; Bashir, Muhammad A.; Gubbins, Mark A.; Czoschke, Peter J.; Lopusnik, Radek
2016-01-01
To meet growing data storage needs, the density of data stored on hard disk drives must increase. In pursuit of this aim, the magnetodynamics of the hard disk write head must be characterized and understood, particularly the process of “flux beaming.” In this study, seven different configurations of perpendicular magnetic recording (PMR) write heads were imaged using time-resolved scanning Kerr microscopy, revealing their detailed dynamic magnetic state during the write process. It was found that the precise position and number of driving coils can significantly alter the formation of flux beams during the write process. These results are applicable to the design and understanding of current PMR and next-generation heat-assisted magnetic recording devices, as well as being relevant to other magnetic devices.
Simple quadratic magneto-optic Kerr effect measurement system using permanent magnets.
Pradeep, A V; Ghosh, Sayak; Anil Kumar, P S
2017-01-01
In recent times, quadratic magneto-optic Kerr effect (QMOKE) is emerging as an important experimental tool to investigate higher-order spin-orbit interactions in magnetic thin films and heterostructures. We have designed and constructed a simple, cost-effective QMOKE measurement system using permanent magnets. The permanent magnets are mounted on the inner surface of a cylindrical ferromagnetic yoke which can be rotated about its axis. Our system is sensitive to both the quadratic and linear MOKE signals. We use rotating field method to extract the QMOKE components in saturation. This system is capable of extracting the QMOKE signal from single crystals and thin film samples. Here we present the construction and working of the QMOKE measurement system using permanent magnets and report, for the first time, the QMOKE signal from Fe 3 O 4 single crystal.
Thermal Casimir effect in Kerr spacetime with quintessence and massive gravitons
Energy Technology Data Exchange (ETDEWEB)
Bezerra, V.B. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, PB (Brazil); Christiansen, H.R. [Ciencia e Tecnologia do Ceara (IFCE), Departamento de Fisica, Instituto Federal de Educacao, Sobral, CE (Brazil); Cunha, M.S. [Universidade Estadual do Ceara, Grupo de Fisica Teorica (GFT), Fortaleza, CE (Brazil); Muniz, C.R.; Tahim, M.O. [Universidade Estadual do Ceara, Faculdade de Educacao, Ciencias e Letras do Sertao Central, Quixada, CE (Brazil)
2017-11-15
Starting from an analytical expression for the Helmholtz free energy we calculate the thermal corrections to the Casimir energy density and entropy within nearby ideal parallel plates in the vacuum of a massless scalar field. Our framework is the Kerr spacetime in the presence of quintessence and massive gravitons. The high and low temperature regimes are especially analyzed in order to distinguish the main contributions. For instance, in the high temperature regime, we show that the force between the plates is repulsive and grows with both the quintessence and the massive gravitons. Regarding the Casimir entropy, our results are in agreement with the Nernst heat theorem and therefore confirm the third law of thermodynamics in the present scenario. (orig.)
Berry phase in a two-atom Jaynes-Cummings model with Kerr medium
International Nuclear Information System (INIS)
Bu Shenping; Zhang Guofeng; Liu Jia; Chen Ziyu
2008-01-01
The Jaynes-Cummings model (JCM) is an very important model for describing interaction between quantized electromagnetic fields and atoms in cavity quantum electrodynamics (QED). This model is generalized in many different directions since it predicts many novel quantum effects that can be verified by modern physics experimental technologies. In this paper, the Berry phase and entropy of the ground state for arbitrary photon number n of a two-atom Jaynes-Cummings model with Kerr-like medium are investigated. It is found that there is some correspondence between their images, especially the existence of a curve in the Δ-ε plane along which the energy, Berry phase and entropy all reach their special values. So it is available for detecting entanglement by applying Berry phase.
Berry phase in a two-atom Jaynes-Cummings model with Kerr medium
Energy Technology Data Exchange (ETDEWEB)
Bu Shenping; Zhang Guofeng; Liu Jia; Chen Ziyu [Department of Physics, School of Science, BeiHang University, Xueyuan Road, Beijing 100083 (China)], E-mail: chenzy@buaa.edu.cn
2008-12-15
The Jaynes-Cummings model (JCM) is an very important model for describing interaction between quantized electromagnetic fields and atoms in cavity quantum electrodynamics (QED). This model is generalized in many different directions since it predicts many novel quantum effects that can be verified by modern physics experimental technologies. In this paper, the Berry phase and entropy of the ground state for arbitrary photon number n of a two-atom Jaynes-Cummings model with Kerr-like medium are investigated. It is found that there is some correspondence between their images, especially the existence of a curve in the {delta}-{epsilon} plane along which the energy, Berry phase and entropy all reach their special values. So it is available for detecting entanglement by applying Berry phase.
Quantized Faraday and Kerr rotation and axion electrodynamics of a 3D topological insulator
Wu, Liang; Salehi, M.; Koirala, N.; Moon, J.; Oh, S.; Armitage, N. P.
2016-12-01
Topological insulators have been proposed to be best characterized as bulk magnetoelectric materials that show response functions quantized in terms of fundamental physical constants. Here, we lower the chemical potential of three-dimensional (3D) Bi2Se3 films to ~30 meV above the Dirac point and probe their low-energy electrodynamic response in the presence of magnetic fields with high-precision time-domain terahertz polarimetry. For fields higher than 5 tesla, we observed quantized Faraday and Kerr rotations, whereas the dc transport is still semiclassical. A nontrivial Berry’s phase offset to these values gives evidence for axion electrodynamics and the topological magnetoelectric effect. The time structure used in these measurements allows a direct measure of the fine-structure constant based on a topological invariant of a solid-state system.
Spin Interaction under the Collision of Two Kerr-(Anti-de Sitter Black Holes
Directory of Open Access Journals (Sweden)
Bogeun Gwak
2017-12-01
Full Text Available We investigate herein the spin interaction during collisions between Kerr-(anti-de Sitter black holes. The spin interaction potential depends on the relative rotation directions of the black holes, and this potential can be released as gravitational radiation upon collision. The energy of the radiation depends on the cosmological constant and corresponds to the spin interaction potential in the limit that one of the black holes has negligibly small mass and angular momentum. We then determine the approximate overall behaviors of the upper bounds on the radiation using thermodynamics. The results indicate that the spin interaction can consistently contribute to the radiation. In addition, the radiation depends on the stability of the black hole produced by the collision.
Radiative evolution of the Carter constant for generic orbits around a Kerr black hole
Ori, Amos
1997-03-01
Recently, we proposed a new approach for the radiative evolution of generic orbits around a Kerr black hole. This involves the calculation of the evolution rate of all three constants of motion: The energy E, the azimuthal angular momentum Lz, and the Carter constant Q. In a previous paper we presented the general approach, and outlined its application to a scalar-field radiation reaction. In the present paper, we give the full details of the scalar-field calculations: We first derive the explicit expressions for Edo;, Ldotz, and Qdot. Then, we compare our results for Edot and Ldotz to those obtained from the standard method, and show that they are in full agreement. In addition, we outline the application of our method to the electromagnetic and gravitational radiation-reaction problem.
Equatorial circular orbits of neutral test particles in the Kerr-Newman spacetime
Pugliese, Daniela; Quevedo, Hernando; Ruffini, Remo
2013-07-01
We present a detailed analysis of the orbital circular motion of electrically neutral test particles on the equatorial plane of the Kerr-Newman spacetime. Many details of the motion in the cases of black hole and naked singularity sources are pointed out. We identify four different types of orbital regions, which depend on the properties of the orbital angular momentum, and define four different kinds of naked singularities, according to the values of the charge-to-mass ratio of the source. It is shown that the presence of a particular type of counterrotating test particle is sufficient to uniquely identify naked singularities. It is pointed out that the structure of the stability regions can be used to differentiate between black holes and naked singularities.
The analytic theory of fluid disks orbiting the Kerr black hole
International Nuclear Information System (INIS)
Kozlowski, M.; Jaroszynski, M.; Abramowicz, M.A.
1978-01-01
Abramowicz et al. (1977) have recently shown that a sharp cusp exists on the inner edge of the accretion fisk (with constant angular momentum), orbiting the Kerr black hole. The cusp resembles very much a similar cusp located on the Roche lobe in the close binary case (Lagrange L 1 point) and therefore its existence is very important from the physical point of view. In this paper we will show that the existence of the cusp is a typical phenomenon for any angular momentum distribution. We will also discuss the physical importance of the cusps. It is proved that the inner edge of any stable disk cannot be closer to the black hole than the marginally bound circular orbit, r = rsub(mb). (orig.) [de
Quantum radiation of Maxwell’s electromagnetic field in nonstationary Kerr-de Sitter black hole
Ibungochouba Singh, T.; Ablu Meitei, I.; Yugindro Singh, K.
2016-03-01
Quantum radiation properties of nonstationary Kerr-de Sitter (KdS) black hole is investigated using the method of generalized tortoise coordinate transformation. The locations of horizons and the temperature of the thermal radiation as well as the maximum energy of the nonthermal radiation are derived. It is found that the surface gravity and the Hawking temperature depend on both time and different angles. An extra coupling effect is obtained in the thermal radiation spectrum of Maxwell’s electromagnetic field equations which is absent in the thermal radiation spectrum of scalar particles. Further, the chemical potential derived from the thermal radiation spectrum of scalar particle has been found to be equal to the highest energy of the negative energy state of the scalar particle in the nonthermal radiation for KdS black hole. It is also shown that the generalized tortoise coordinate transformation produces a constant term in the expression of the surface gravity and Hawking temperature.
Ivanov, Yurii P.
2014-02-14
The magneto-optic Kerr effect has been employed to determine the magnetization process and estimate the domain structure of microwires with circular magnetic anisotropy. The diameter of microwires was 8 μm, and pieces 2 cm long were selected for measurements. The analysis of the local surface longitudinal and transverse hysteresis loops has allowed us to deduce a vortex magnetic structure with axial core and circular external shell. Moreover, a bamboo-like surface domain structure is confirmed with wave length of around 10 to 15 μm and alternating chirality in adjacent circular domains. The width of the domain wall is estimated to be less than 3 μm. Finally, closure domain structures with significant helical magnetization component are observed extending up to around 1000 μm from the end of the microwire.
Directory of Open Access Journals (Sweden)
Alejandro Cárdenas-Avendaño
2016-09-01
Full Text Available The recent announcement of the detection of gravitational waves by the LIGO/Virgo Collaboration has opened a new window to test the nature of astrophysical black holes. Konoplya & Zhidenko have shown how the LIGO data of GW 150914 can constrain possible deviations from the Kerr metric. In this letter, we compare their constraints with those that can be obtained from accreting black holes by fitting their X-ray reflection spectrum, the so-called iron line method. We simulate observations with eXTP, a next generation X-ray mission, finding constraints much stronger than those obtained by Konoplya & Zhidenko. Our results can at least show that, contrary to what is quite commonly believed, it is not obvious that gravitational waves are the most powerful approach to test strong gravity. In the presence of high quality data and with the systematics under control, the iron line method may provide competitive constraints.
Quantized Faraday and Kerr rotation and axion electrodynamics of a 3D topological insulator.
Wu, Liang; Salehi, M; Koirala, N; Moon, J; Oh, S; Armitage, N P
2016-12-02
Topological insulators have been proposed to be best characterized as bulk magnetoelectric materials that show response functions quantized in terms of fundamental physical constants. Here, we lower the chemical potential of three-dimensional (3D) Bi 2 Se 3 films to ~30 meV above the Dirac point and probe their low-energy electrodynamic response in the presence of magnetic fields with high-precision time-domain terahertz polarimetry. For fields higher than 5 tesla, we observed quantized Faraday and Kerr rotations, whereas the dc transport is still semiclassical. A nontrivial Berry's phase offset to these values gives evidence for axion electrodynamics and the topological magnetoelectric effect. The time structure used in these measurements allows a direct measure of the fine-structure constant based on a topological invariant of a solid-state system. Copyright © 2016, American Association for the Advancement of Science.
Energy Technology Data Exchange (ETDEWEB)
Cárdenas-Avendaño, Alejandro [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Programa de Matemática, Fundación Universitaria Konrad Lorenz, 110231 Bogotá (Colombia); Jiang, Jiachen [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Bambi, Cosimo, E-mail: bambi@fudan.edu.cn [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Theoretical Astrophysics, Eberhard-Karls Universität Tübingen, 72076 Tübingen (Germany)
2016-09-10
The recent announcement of the detection of gravitational waves by the LIGO/Virgo Collaboration has opened a new window to test the nature of astrophysical black holes. Konoplya & Zhidenko have shown how the LIGO data of GW 150914 can constrain possible deviations from the Kerr metric. In this letter, we compare their constraints with those that can be obtained from accreting black holes by fitting their X-ray reflection spectrum, the so-called iron line method. We simulate observations with eXTP, a next generation X-ray mission, finding constraints much stronger than those obtained by Konoplya & Zhidenko. Our results can at least show that, contrary to what is quite commonly believed, it is not obvious that gravitational waves are the most powerful approach to test strong gravity. In the presence of high quality data and with the systematics under control, the iron line method may provide competitive constraints.
Giant Planets: Good Neighbors for Habitable Worlds?
Georgakarakos, Nikolaos; Eggl, Siegfried; Dobbs-Dixon, Ian
2018-04-01
The presence of giant planets influences potentially habitable worlds in numerous ways. Massive celestial neighbors can facilitate the formation of planetary cores and modify the influx of asteroids and comets toward Earth analogs later on. Furthermore, giant planets can indirectly change the climate of terrestrial worlds by gravitationally altering their orbits. Investigating 147 well-characterized exoplanetary systems known to date that host a main-sequence star and a giant planet, we show that the presence of “giant neighbors” can reduce a terrestrial planet’s chances to remain habitable, even if both planets have stable orbits. In a small fraction of systems, however, giant planets slightly increase the extent of habitable zones provided that the terrestrial world has a high climate inertia. In providing constraints on where giant planets cease to affect the habitable zone size in a detrimental fashion, we identify prime targets in the search for habitable worlds.
Numerical study of the quasinormal mode excitation of Kerr black holes
International Nuclear Information System (INIS)
Dorband, Ernst Nils; Diener, Peter; Tiglio, Manuel; Berti, Emanuele; Schnetter, Erik
2006-01-01
We present numerical results from three-dimensional evolutions of scalar perturbations of Kerr black holes. Our simulations make use of a high-order accurate multiblock code which naturally allows for adapted grids and smooth inner (excision) and outer boundaries. We focus on the quasinormal ringing phase, presenting a systematic method for extraction of the quasinormal mode frequencies and amplitudes and comparing our results against perturbation theory. The detection of a single mode in a ringdown waveform allows for a measurement of the mass and spin of a black hole; a multimode detection would allow a test of the Kerr nature of the source. Since the possibility of a multimode detection depends on the relative mode amplitude, we study this topic in some detail. The amplitude of each mode depends exponentially on the starting time of the quasinormal regime, which is not defined unambiguously. We show that this time-shift problem can be circumvented by looking at appropriately chosen relative mode amplitudes. From our simulations we extract the quasinormal frequencies and the relative and absolute amplitudes of corotating and counterrotating modes (including overtones in the corotating case). We study the dependence of these amplitudes on the shape of the initial perturbation, the angular dependence of the mode, and the black hole spin, comparing against results from perturbation theory in the so-called asymptotic approximation. We also compare the quasinormal frequencies from our numerical simulations with predictions from perturbation theory, finding excellent agreement. For rapidly rotating black holes (of spin j=0.98) we can extract the quasinormal frequencies of not only the fundamental mode, but also of the first two overtones. Finally we study under what conditions the relative amplitude between given pairs of modes gets maximally excited and present a quantitative analysis of rotational mode-mode coupling. The main conclusions and techniques of our
Solitary ulcerated congenital giant juvenile xanthogranuloma
Directory of Open Access Journals (Sweden)
Su Yuen Ng
2015-01-01
Full Text Available A 3-month-old female patient with a giant ulcerated nodule over the back since birth was diagnosed as congenital giant juvenile xanthogranuloma (JXG based on clinical and histopathological examination. Congenital giant JXG with ulceration at birth is a rare presentation of JXG and commonly misdiagnosed. This case emphasizes the importance of being aware of the myriad presentations of JXG in order to make a correct diagnosis and avoid unnecessary investigations or treatment.
Induced modulation instability and recurrence in nonlocal nonlinear media
Energy Technology Data Exchange (ETDEWEB)
Beeckman, J; Neyts, K [Liquid Crystals and Photonics Group, Department of Electronics and Information Systems, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Gent (Belgium); Haelterman, M [Service d' optique et acoustique, Universite libre de Bruxelles CP 194/5, 50 avenue F D Roosevelt, 1050 Bruxelles (Belgium)], E-mail: jeroen.beeckman@elis.ugent.be
2008-03-28
The long-term behaviour of spatial modulation instability in nonlocal nonlinear Kerr media is studied theoretically and numerically. Seeding the modulation instability with a periodic modulation leads to an energy transfer to higher-order modes and the long-term behaviour of the system shows the Fermi-Pasta-Ulam recurrence. For large spatial frequencies, close to the cut-off frequency, the stable solution can be found analytically. The propagation with an initial state different from the stable solution results in a propagation circling around the stable point. For general frequencies, the calculation of the stable point is performed numerically. Comparison of the calculations with earlier reported experimental results in nematic liquid crystals shows a satisfactory agreement.
Westra, H.J.R.
2012-01-01
In this Thesis, nonlinear dynamics and nonlinear interactions are studied from a micromechanical point of view. Single and doubly clamped beams are used as model systems where nonlinearity plays an important role. The nonlinearity also gives rise to rich dynamic behavior with phenomena like
Giant dipole resonance in hot nuclei
International Nuclear Information System (INIS)
Mau, N.V.
1993-01-01
Giant resonances built on an excited state of the nucleus at a finite temperature T are studied. The following questions are investigated: how long such collective effects occur in a nucleus when T increases. How the properties of the giant resonances vary when the temperature increases. How the study of giant resonances in hot nuclei can give information on the structure of the nucleus in a highly excited state. The special case of the giant dipole resonance is studied. Some of the experimental results are reviewed and in their theoretical interpretation is discussed. (K.A.). 56 refs., 20 figs., 4 tabs
Dikandé, Alain M.; Voma Titafan, J.; Essimbi, B. Z.
2017-10-01
The transition dynamics from continuous-wave to pulse regimes of operation for a generic model of passively mode-locked lasers with saturable absorbers, characterized by an active medium with non-Kerr nonlinearity, are investigated analytically and numerically. The system is described by a complex Ginzburg-Landau equation with a general m:n saturable nonlinearity (i.e {I}m/{(1+{{Γ }}I)}n, where I is the field intensity and m and n are two positive numbers), coupled to a two-level gain equation. An analysis of stability of continuous waves, following the modulational instability approach, provides a global picture of the self-starting dynamics in the system. The analysis reveals two distinct routes depending on values of the couple (m, n), and on the dispersion regime: in the normal dispersion regime, when m = 2 and n is arbitrary, the self-starting requires positive values of the fast saturable absorber and nonlinearity coefficients, but negative values of these two parameters for the family with m = 0. However, when the spectral filter is negative, the laser can self-start for certain values of the input field and the nonlinearity saturation coefficient Γ. The present work provides a general map for the self-starting mechanisms of rare-earth doped figure-eight fiber lasers, as well as Kerr-lens mode-locked solid-state lasers.
Arshad, Muhammad; Seadawy, Aly R.; Lu, Dianchen
2017-12-01
In optical fibers, the higher order non-linear Schrödinger equation (NLSE) with cubic quintic nonlinearity describes the propagation of extremely short pulses. We constructed bright and dark solitons, solitary wave and periodic solitary wave solutions of generalized higher order NLSE in cubic quintic non Kerr medium by applying proposed modified extended mapping method. These obtained solutions have key applications in physics and mathematics. Moreover, we have also presented the formation conditions on solitary wave parameters in which dark and bright solitons can exist for this media. We also gave graphically the movement of constructed solitary wave and soliton solutions, that helps to realize the physical phenomena's of this model. The stability of the model in normal dispersion and anomalous regime is discussed by using the modulation instability analysis, which confirms that all constructed solutions are exact and stable. Many other such types of models arising in applied sciences can also be solved by this reliable, powerful and effective method.
Directory of Open Access Journals (Sweden)
V. S. Serov
2010-01-01
Full Text Available A method based on the Banach fixed-point theorem is proposed for obtaining certain solutions (TE-polarized electromagnetic waves of the Helmholtz equation describing the reflection and transmission of a plane monochromatic wave at a nonlinear lossy dielectric film situated between two lossless linear semiinfinite media. All three media are assumed to be nonmagnetic and isotropic. The permittivity of the film is modelled by a continuously differentiable function of the transverse coordinate with a saturating Kerr nonlinearity. It is shown that the solution of the Helmholtz equation exists in form of a uniformly convergent sequence of iterations of the equivalent Volterra integral equation. Numerical results are presented.
Giant magneto-resistance devices
Hirota, Eiichi; Inomata, Koichiro
2002-01-01
This book deals with the application of giant magneto-resistance (GMR) effects to electronic devices. It will appeal to engineers and graduate students in the fields of electronic devices and materials. The main subjects are magnetic sensors with high resolution and magnetic read heads with high sensitivity, required for hard-disk drives with recording densities of several gigabytes. Another important subject is novel magnetic random-access memories (MRAM) with non-volatile non-destructive and radiation-resistant characteristics. Other topics include future GMR devices based on bipolar spin transistors, spin field-effect transistors (FETs) and double-tunnel junctions.
Analysis of giant electrorheological fluids.
Seo, Youngwook P; Seo, Yongsok
2013-07-15
The yield stress dependence on electric field strength for giant electrorheological (GER) fluids over the full range of electric fields was examined using Seo's scaling function which incorporated both the polarization and the conductivity models. If a proper scaling was applied to the yield stress data to collapse them onto a single curve, the Seo's scaling function could correctly fit the yield stress behavior of GER suspensions, even at very high electric field strengths. The model predictions were also compared with recently proposed Choi et al.'s model to allow a consideration of the universal framework of ER fluids. Copyright © 2013 Elsevier Inc. All rights reserved.
Totally thrombosed giant anterior communicating artery aneurysm
Directory of Open Access Journals (Sweden)
V R Roopesh Kumar
2015-01-01
Full Text Available Giant anterior communicating artery aneurysmsarerare. Apatient presented with visual dysfunction, gait ataxia and urinary incontinence. MRI showed a giant suprasellar mass.At surgery, the lesion was identified as being an aneurysm arising from the anterior communicating artery.The difficulty in preoperative diagnosis and relevant literature are reviewed.
Giant Cell Tumor of the Infratemporal Fossa
Gibbons, Kevin; Singh, Anand; Kuriakose, M. Abraham; Loree, Thom R.; Harris, Kenneth; Rubenfeld, Ari; Goodloe, Samuel; Hicks, Wesley L.
2000-01-01
Giant cell tumors are an uncommon neoplasm; most are found in the long bones, formed by endochondral ossification. This article presents a case of giant cell tumor of the infratemporal fossa, which by radiographic and clinical examination appears to have originated in the squamous portion of the temporal bone.
Giant Cell Tumor of the Infratemporal Fossa
Gibbons, Kevin; Singh, Anand; Kuriakose, M. Abraham; Loree, Thom R.; Harris, Kenneth; Rubenfeld, Ari; Goodloe, Samuel; Hicks, Wesley L.
2000-01-01
Giant cell tumors are an uncommon neoplasm; most are found in the long bones, formed by endochondral ossification. This article presents a case of giant cell tumor of the infratemporal fossa, which by radiographic and clinical examination appears to have originated in the squamous portion of the temporal bone. ImagesFigure 1Figure 2Figure 3 PMID:17171141
Evolution and history of Giant Sequoia
H. Thomas Harvey
1986-01-01
Ancient ancestors of the giant sequoia (Sequoiadendron giganteum [Lindl.] Buchholz) were widespread throughout much of the Northern Hemisphere during the late Mesozoic Period. Climatic conditions changed, forcing the more recent ancestors of present giant sequoia into the southwestern United States. The native range is now restricted to the west slope of the Sierra...
Giant bladder diverticulum in a boy
Directory of Open Access Journals (Sweden)
Esra Ozcakir
2014-01-01
Full Text Available Although the bladder diverticula in children are seen commonly which is association with infravesical obstruction or neurogenic bladder function, the case of giant congenital bladder diverticula are rare. In this paper, an 11 years old boy with giant bladder diverticula presenting urinary infections is evaluated in terms of diagnosis and management by current literature.
Nutritional evaluation of the giant grassropper (Zonocerus ...
African Journals Online (AJOL)
The biological value of giant grasshopper protein (Zonocerus variegatus) was evaluated by comparing the weight gained, food efficiency ratio (FER), protein efficiency ratio (PER) of rats fed standard laboratory chow with that of rats fed giant grasshopper, Soyabean(Glycine max) and crayfish. The effect of high fibre content ...
Giant lower oesophageal ulcer Bushman baby
African Journals Online (AJOL)
1983-02-26
Feb 26, 1983 ... Giant lower oesophageal ulcer. Bushman baby. A case report. J. J. HEYDENRYCH, A. D. KEET. •. ID a. Summary. The case of a giant, penetrating lower oesophageal ulcer in a 14-month-old Bushman baby is reported. ... crying precluded a thorough systematic examination. Food was immediately rejected.
Dispersive shock mediated resonant radiations in defocused nonlinear medium
Bose, Surajit; Chattopadhyay, Rik; Bhadra, Shyamal Kumar
2018-04-01
We report the evolution of resonant radiation (RR) in a self-defocused nonlinear medium with two zero dispersion wavelengths. RR is generated from dispersive shock wave (DSW) front when the pump pulse is in non-solitonic regime close to first zero dispersion wavelength (ZDW). DSW is responsible for pulse splitting resulting in the generation of blue solitons when leading edge of the pump pulse hits the first ZDW. DSW also generates a red shifted dispersive wave (DW) in the presence of higher order dispersion coefficients. Further, DSW through cross-phase modulation with red shifted dispersive wave (DW) excites a localized radiation. The presence of zero nonlinearity point in the system restricts red-shift of RR and enhances the red shifting of DW. It also helps in the formation of DSW at shorter distance and squeezes the solitonic region beyond second zero dispersion point. Predicted results indicate that the spectral evolution depends on the product of Kerr nonlinearity and group velocity dispersion.
Delayed Higher-Order Optical Nonlinearities in Noble Gases
Tarazkar, Maryam; Romanov, Dmitri; Levis, Robert
2014-05-01
The role of higher-order Kerr effect (HOKE) in femtosecond laser filamentation is currently at the center of a controversy, as alleged crossover from positive to negative nonlinear refractive index at higher intensities was proposed to cause filament stabilization. Experimental evidence of HOKE crossover or lack thereof is being hotly debated. Motivated by this debate, we report the frequency-dependent nonlinear refractive index coefficients n2 and n4 for a series of atmospheric-pressure noble gases: helium, neon, argon, krypton, and xenon. The corresponding atomic hyperpolarizability coefficients are obtained via auxiliary static electric field approach developed on the basis of ab initio calculations implemented in Dalton program and performed at the CCSD level of theory with t-Aug-cc-PV5Z basis set. The n4 index is obtained using the relations between the degenerate six-wave mixing coefficient and some other frequency-dependent second hyperpolarizability coefficients, which can be calculated on the basis of n2via the auxiliary field approach. For all the investigated gases, the n4 indices are found to be positive over the wavelength range 300 nm-1500 nm. This result runs counter to the HOKE crossover hypothesis. The calculated n4 indices demonstrate considerable temporal dispersion, which progressively increases from helium to xenon. This feature implies delayed nonlinearity and calls for modifications in current theoretical models of filamentation process. We gratefully acknowledge financial support through AFOSR MURI Grant No. FA9550-10-1-0561.
Optical tristability and ultrafast Fano switching in nonlinear magnetoplasmonic nanoparticles
Yu, Wenjing; Ma, Pujuan; Sun, Hua; Gao, Lei; Noskov, Roman E.
2018-02-01
We consider light scattering by a coated magnetoplasmonic nanoparticle with a Kerr-type nonlinear plasmonic shell and a magneto-optic core. Such a structure features two plasmon dipole modes, associated with electronic oscillations on the inner and outer surfaces of the shell. Driven in a nonlinear regime, each mode exhibits a bistable response. Bistability of an inner plasmon leads to switching between this state and a Fano resonance (Fano switching). Once the external light intensity exceeds a critical value, the bistability zones of both eigenmodes overlap, yielding optical tristability characterized by three stable steady states for a given wavelength and light intensity. We develop a dynamic theory of transitions between nonlinear steady states and estimate the characteristic switching time to be as short as 0.5 ps. We also show that the magneto-optical effect allows red and blue spectral shifts of the Fano profile for right and left circular polarizations of the external light, rendering Fano switching sensitive to light polarization. Specifically, one can reach Fano switching for the right circular polarization while cancelling it for the left circular polarization. The results point to a class of ultrafast Fano switchers tunable by a magnetic field for applications in nanophotonics.
Modeling of Nonlinear Optical Response in Gaseous Media and Its Comparison with Experiment
Xia, Yi
This thesis demonstrates the model and application of nonlinear optical response with Metastable Electronic State Approach (MESA) in ultrashort laser propagation and verifies accuracy of MESA through extensive comparison with experimental data. The MESA is developed from quantum mechanics to describe the nonlinear off-resonant optical response together with strong-field ionization in gaseous medium. The conventional light-matter interaction models are based on a piece-wise approach where Kerr effect and multi-photon ionization are treated as independent nonlinear responses. In contrast, MESA is self-consistent as the response from freed electrons and bound electrons are microscopically linked. It also can be easily coupled to the Unidirectional Pulse Propagation Equations (UPPE) for large scale simulation of experiments. This work tests the implementation of MESA model in simulation of nonlinear phase transients of ultrashort pulse propagation in a gaseous medium. The phase transient has been measured through Single-Shot Supercontinuum Spectral Interferometry. This technique can achieve high temporal resolution (10 fs) and spatial resolution (5 mum). Our comparison between simulation and experiment gives a quantitive test of MESA model including post-adiabatic corrections. This is the first time such a comparison was achieved for a theory suitable for large scale numerical simulation of modern nonlinear-optics experiments. In more than one respect, ours is a first-of-a-kind achievement. In particular, • Large amount of data are compared. We compare the data of nonlinear response induced by different pump intensity in Ar and Nitrogen. The data sets are three dimensions including two transverse spacial dimensions and one axial temporal dimension which reflect the whole structure of nonlinear response including the interplay between Kerr and plasma-induced effects. The resolutions of spatial and temporal dimension are about a few micrometer and several femtosecond
Kordts, A; Pfeiffer, M H P; Guo, H; Brasch, V; Kippenberg, T J
2016-02-01
High-Q silicon nitride (SiN) microresonators enable optical Kerr frequency comb generation on a photonic chip and have recently been shown to support fully coherent combs based on temporal dissipative Kerr soliton formation. For bright soliton formation, it is necessary to operate SiN waveguides in the multimode regime in order to produce waveguide induced anomalous group velocity dispersion. However, this regime can lead to local disturbances of the dispersion due to avoided crossings caused by coupling between different mode families and, therefore, prevent the soliton formation. Here, we demonstrate that a single-mode "filtering" section inside high-Q resonators enables efficiently suppression of avoided crossings, while preserving high quality factors (Q∼10(6)). We verify the approach by demonstrating single soliton formation in SiN resonators with a filtering section.
From red giants to planetary nebulae
International Nuclear Information System (INIS)
Kwok, S.
1982-01-01
The transition from red giants to planetary nebulae is studied by comparing the spectral characteristics of red giant envelopes and planetary nebulae. Observational and theoretical evidence both suggest that remnants of red giant envelopes may still be present in planetary nebula systems and should have significant effects on their formation. The dynamical effects of the interaction of stellar winds from central stars of planetary nebulae with the remnant red giant envelopes are evaluated and the mechanism found to be capable of producing the observed masses and momenta of planetary nebulae. The observed mass-radii relation of planetary nebulae may also be best explained by the interacting winds model. The possibility that red giant mass loss, and therefore the production of planetary nebulae, is different between Population I and II systems is also discussed
Direct observation of magnetic domains by Kerr microscopy in a Ni-Mn-Ga magnetic shape-memory alloy
Czech Academy of Sciences Publication Activity Database
Perevertov, Oleksiy; Heczko, Oleg; Schaefer, R.
2017-01-01
Roč. 95, č. 14 (2017), s. 1-5, č. článku 144431. ISSN 2469-9950 R&D Projects: GA ČR GA15-00262S Institutional support: RVO:68378271 Keywords : shape memory * magnetic domains * Kerr microscopy * N-Mn-Ga alloy Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.836, year: 2016
Bao, Chengying; Zhang, Lin; Kimerling, Lionel C; Michel, Jurgen; Yang, Changxi
2015-07-13
We investigate the impact of stimulated Raman scattering (SRS) and self-steepening (SS) on breather soliton dynamics in octave-spanning Kerr frequency comb generation. SRS and SS can transform chaotic fluctuations in cavity solitons into periodic breathing. Furthermore, with SRS and SS considered, bandwidth of the soliton breathes more than two times stronger. The simultaneous presence of SRS and SS also make the soliton breathe slower and degrades the coherence of the soliton.
Lan, Xiao-Gang
2012-04-01
The Hawking effect of Dirac particles in a non-stationary Kerr-Newman black hole is investigated using an improved Damour-Ruffini method with a new tortoise coordinate transformation. In contrast with the old tortoise coordinate, the new one satisfies the dimensional requirement. It is interesting to note that the Hawking emission spectrum remains a blackbody one with a correction term ξ existing in the Hawking temperature. Compared with the old tortoise coordinate transformation, our results appears more accurate and reliable.
Zhu, X D
2017-08-01
I present a detailed account of a zero loop-area Sagnac interferometer operated at oblique incidence for detecting magneto-optic Kerr effects arising from a magnetized sample. In particular, I describe the symmetry consideration and various optical arrangements available to such an interferometer that enables measurements of magneto-optic effects due to both in-plane and out-of-plane magnetization of the sample with optimizable signal-to-noise ratios.
Electromagnetic decay of giant resonances
International Nuclear Information System (INIS)
Beene, J.R.; Bertrand, F.E.; Halbert, M.L.; Auble, R.L.; Hensley, D.C.; Horen, D.J.; Robinson, R.L.; Sayer, R.O.; Sjoreen, T.P.
1985-01-01
Coincidence experiments were done to investigate the photon and neutron emission from the giant resonance regions of 208 Pb and 90 Zr using the ORNL Spin Spectrometer, a 72-segment NaI detector system. We have determined the total gamma-decay probability, the ground-state gamma branching ratio, and the branching ratios to a number of low-lying states as a function of excitation energy in 208 Pb to approx.15 MeV. Similar data were also obtained on 90 Zr. The total yield of ground-state E2 gamma radiation in 208 Pb and the comparative absence of such radiation in 90 Zr can only be understood if decay of compound (damped) states is considered. Other observations in 208 Pb include the absence of a significant branch from the giant quadrupole resonance (GQR) to the 3 - state at 2.6 MeV, a strong branch to a 3 - state at 4.97 MeV from the same region, and transitions to various 1 - states between 5 to 7 MeV from the E* approx. 14 MeV region (EO resonance)
Nonlinear elliptic differential equations with multivalued nonlinearities
Indian Academy of Sciences (India)
Springer Verlag Heidelberg #4 2048 1996 Dec 15 10:16:45
Nonlinear elliptic differential equations with multivalued ... has a solution. Finally in the last part we consider an eigenvalue problem with a nonmonotone multivalued nonlinearity. Using the critical point theory for nonsmooth .... A is upper semicontinuous (as a set-valued map) from every finite dimensional subspace of X into ...
Polewko-Klim, A; Uba, S; Uba, L
2014-07-01
A solution to the problem of disturbing effect of the background Faraday rotation in the cryostat windows on longitudinal magneto-optical Kerr effect (LMOKE) measured under vacuum conditions and/or at low temperatures is proposed. The method for eliminating the influence of Faraday rotation in cryostat windows is based on special arrangement of additional mirrors placed on sample holder. In this arrangement, the orientation of the cryostat window is perpendicular to the light beam direction and parallel to an external magnetic field generated by the H-frame electromagnet. The operation of the LMOKE magnetometer with the special sample holder based on polarization modulation technique with a photo-elastic modulator is theoretically analyzed with the use of Jones matrices, and formulas for evaluating of the actual Kerr rotation and ellipticity of the sample are derived. The feasibility of the method and good performance of the magnetometer is experimentally demonstrated for the LMOKE effect measured in Fe/Au multilayer structures. The influence of imperfect alignment of the magnetometer setup on the Kerr angles, as derived theoretically through the analytic model and verified experimentally, is examined and discussed.
Magneto-optical Kerr spectra and magnetic properties of Co-substituted M-type strontium ferrites
Energy Technology Data Exchange (ETDEWEB)
Liu Xiansong, E-mail: xiansongliu@ahu.edu.cn [Engineering Technology Research Center of Magnetic Materials, Anhui Province, School of Physics and Materials Science, Anhui University, Hefei 230039 (China); Fernandez-Garcia, Lucia [Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo UO - Principado de Asturias, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain); Hu Feng; Zhu Deru [Engineering Technology Research Center of Magnetic Materials, Anhui Province, School of Physics and Materials Science, Anhui University, Hefei 230039 (China); Suarez, Marta; Menendez, Jose Luis [Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo UO - Principado de Asturias, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain)
2012-04-16
Highlights: Black-Right-Pointing-Pointer Prepare single phase ferrites by substituted with Co{sup 2+}. Black-Right-Pointing-Pointer The magnetic properties were remarkably modified. Black-Right-Pointing-Pointer A very noticeable Kerr activity was obtained for the Co-substituted ferrites. - Abstract: M-type strontium ferrites SrFe{sub 12-x}Co{sub x}O{sub 19} (x = 0, 0.05, 0.10, 0.15, 0.20) were prepared by the conventional ceramic technology. The structure, magnetic properties and magneto-optical Kerr activity of the samples were investigated by X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and magneto-optical ellipsometry, respectively. X-ray diffraction showed that all the samples were single phase ferrites. The magnetic properties, especially the coercive field, were remarkably modified due to the substitution of cobalt. Most importantly, a noticeable Kerr activity was demonstrated in the Co-substituted M-type strontium ferrites with x = 0.20.
AFM study of combinatorial Ga sup + implanted Co sub 7 Ag sub 9 sub 3 film and its Kerr effect
Cai Ying Wen; Wei Lun; Li Jian Guo; Li Ai Guo; Ni Xin Bo; Zhang Gui Lin; Wang Song You; Shen Zuo Cheng; Li Jin; Chen Liang Yao
2002-01-01
A magneto-optic chip was prepared on Si wafer by combinatorial Ga sup + implantation into ion sputtered Co sub 7 Ag sub 9 sub 3 film. The surface morphology of each unit of the chip was detected by AFM, while their Kerr effect was measured by MOKE equipment. It is observed that the maximum Kerr rotation (MKR) occurs when the incident photon energy is around 3.8-3.9 eV. Summarisation of MKR versus implanted Ga sup + dose shows that the MKR enhancement by Ga sup + implantation can be characterized as incubation, enhancement and saturation regions. Considering the mutual solubility and surface morphology transition after annealing, it is suggested that Ga sup + tends to form CoGa and/or CoGa sub 3 intermetallic compounds. Before the formation of CoGa sub 3 compounds, no apparent MKR enhancement could be observed. While when the surface is half occupied by forest-like CoGa sub 3 compounds, MKR enhancement will be saturated. By comparison of the maximum Kerr rotation with the cone areal density, it can be induced ...
Pani, Paolo; Berti, Emanuele; Gualtieri, Leonardo
2013-06-14
The most general stationary black-hole solution of Einstein-Maxwell theory in vacuum is the Kerr-Newman metric, specified by three parameters: mass M, spin J, and charge Q. Within classical general relativity, one of the most important and challenging open problems in black-hole perturbation theory is the study of gravitational and electromagnetic fields in the Kerr-Newman geometry, because of the indissoluble coupling of the perturbation functions. Here we circumvent this long-standing problem by working in the slow-rotation limit. We compute the quasinormal modes up to linear order in J for any value of Q and provide the first, fully consistent stability analysis of the Kerr-Newman metric. For scalar perturbations the quasinormal modes can be computed exactly, and we demonstrate that the method is accurate within 3% for spins J/J(max) ≲ 0.5, where J(max) is the maximum allowed spin for any value of Q. Quite remarkably, we find numerical evidence that the axial and polar sectors of the gravitoelectromagnetic perturbations are isospectral to linear order in the spin. The extension of our results to nonasymptotically flat space-times could be useful in the context of gauge-gravity dualities and string theory.
Rotation angle of magneto-optical Kerr effect with different capping layer on CoFe film
International Nuclear Information System (INIS)
Wu, K.-M.; Wang, J.-F.; Chen, K.-C.; Wu, J.-C.; Horng, Lance
2007-01-01
To understand the influence of rotation angle in magneto-optical effect between conductor and insulator capping layer, we fabricate Co 50 Fe 50 /Ta, Co 50 Fe 50 /MgO, and Co 50 Fe 50 /SiN x bilayers with fixed CoFe thickness and modulated capping layer to systematically study the dependence on the thickness and material of capping layer. We also changed the CoFe thickness with fixed Ta. The switching characteristics were studied using longitudinal magneto-optic Kerr effect (LMOKE) techniques. The hysteresis loops (MH loops) and the coercivity measured by AGM are independent of the capping layer. Our data show the Kerr rotation angle as a function of capping layer thickness. Based on our calculations, the effective rotation angle changes with different capping material. The phenomenon of the increasing Kerr rotation angle is known to be dependent on the dielectric constant and refractive index of the capping layer. A comparison between the rotation angle in LMOKE and the material property has led to a better understanding of the relationship of light refracted in Ta, MgO and SiN x
Single-photon blockade in a hybrid cavity-optomechanical system via third-order nonlinearity
Sarma, Bijita; Sarma, Amarendra K.
2018-04-01
Photon statistics in a weakly driven optomechanical cavity, with Kerr-type nonlinearity, are analyzed both analytically and numerically. The single-photon blockade effect is demonstrated via calculations of the zero-time-delay second-order correlation function g (2)(0). The analytical results obtained by solving the Schrödinger equation are in complete conformity with the results obtained through numerical solution of the quantum master equation. A systematic study on the parameter regime for observing photon blockade in the weak coupling regime is reported. The parameter regime where the photon blockade is not realizable due to the combined effect of nonlinearities owing to the optomechanical coupling and the Kerr-effect is demonstrated. The experimental feasibility with state-of-the-art device parameters is discussed and it is observed that photon blockade could be generated at the telecommunication wavelength. An elaborate analysis of the thermal effects on photon antibunching is presented. The system is found to be robust against pure dephasing-induced decoherences and thermal phonon number fluctuations.
Study of Nonlinear Propagation of Ultrashort Laser Pulses and Its Application to Harmonic Generation
Weerawarne, Darshana L.
Laser filamentation, which is one of the exotic nonlinear optical phenomena, is self-guidance of high-power laser beams due to the dynamic balance between the optical Kerr effect (self-focusing) and other nonlinear effects such as plasma defocusing. It has many applications including supercontinuum generation (SCG), high-order harmonic generation (HHG), lightning guiding, stand-off sensing, and rain making. The main focus of this work is on studying odd-order harmonic generation (HG) (i.e., 3o, 5o, 7o, etc., where o is the angular frequency) in centrosymmetric media while a high-power, ultrashort harmonic-driving pulse undergoes nonlinear propagation such as laser filamentation. The investigation of highly-controversial nonlinear indices of refraction by measuring low-order HG in air is carried out. Furthermore, time-resolved (i.e., pump-probe) experiments and significant harmonic enhancements are presented and a novel HG mechanism based on higher-order nonlinearities is proposed to explain the experimental results. C/C++ numerical simulations are used to solve the nonlinear Schrodinger equation (NLSE) which supports the experimental findings. Another project which I have performed is selective sintering using lasers. Short-pulse lasers provide a fascinating tool for material processing, especially when the conventional oven-based techniques fail to process flexible materials for smart energy/electronics applications. I present experimental and theoretical studies on laser processing of nanoparticle-coated flexible materials, aiming to fabricate flexible electronic devices.
Krückel, Clemens J; Fülöp, Attila; Klintberg, Thomas; Bengtsson, Jörgen; Andrekson, Peter A; Torres-Company, Víctor
2015-10-05
In this paper we introduce a low-stress silicon enriched nitride platform that has potential for nonlinear and highly integrated optics. The manufacturing process of this platform is CMOS compatible and the increased silicon content allows tensile stress reduction and crack free layer growth of 700 nm. Additional benefits of the silicon enriched nitride is a measured nonlinear Kerr coefficient n(2) of 1.4·10(-18) m(2)/W (5 times higher than stoichiometric silicon nitride) and a refractive index of 2.1 at 1550 nm that enables high optical field confinement allowing high intensity nonlinear optics and light guidance even with small bending radii. We analyze the waveguide loss (∼1 dB/cm) in a spectrally resolved fashion and include scattering loss simulations based on waveguide surface roughness measurements. Detailed simulations show the possibility for fine dispersion and nonlinear engineering. In nonlinear experiments we present continuous-wave wavelength conversion and demonstrate that the material does not show nonlinear absorption effects. Finally, we demonstrate microfabrication of resonators with high Q-factors (∼10(5)).
On Poisson Nonlinear Transformations
Directory of Open Access Journals (Sweden)
Nasir Ganikhodjaev
2014-01-01
Full Text Available We construct the family of Poisson nonlinear transformations defined on the countable sample space of nonnegative integers and investigate their trajectory behavior. We have proved that these nonlinear transformations are regular.
Terahertz semiconductor nonlinear optics
DEFF Research Database (Denmark)
Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias
2013-01-01
In this proceedings we describe our recent results on semiconductor nonlinear optics, investigated using single-cycle THz pulses. We demonstrate the nonlinear absorption and self-phase modulation of strong-field THz pulses in doped semiconductors, using n-GaAs as a model system. The THz nonlinear...
Nonlinear Microwave Optomechanics
Shevchuk, O.
2017-01-01
The nonlinearity is essential for creation of non-classical states of the cavity or mechanical resonator such as squeezed or cat states. A microwave cavity can be made nonlinear by, for instance, adding Josephson junctions. The mechanical resonator is inherently nonlinear. The radiation pressure
Chen, Xianfeng; Zeng, Heping; Guo, Qi; She, Weilong
2015-01-01
This book presents an overview of the state of the art of nonlinear optics from weak light nonlinear optics, ultrafast nonlinear optics to electro-optical theory and applications. Topics range from the fundamental studies of the interaction between matter and radiation to the development of devices, components, and systems of tremendous commercial interest for widespread applications in optical telecommunications, medicine, and biotechnology.
STRONG FIELD EFFECTS ON EMISSION LINE PROFILES: KERR BLACK HOLES AND WARPED ACCRETION DISKS
International Nuclear Information System (INIS)
Wang Yan; Li Xiangdong
2012-01-01
If an accretion disk around a black hole is illuminated by hard X-rays from non-thermal coronae, fluorescent iron lines will be emitted from the inner region of the accretion disk. The emission line profiles will show a variety of strong field effects, which may be used as a probe of the spin parameter of the black hole and the structure of the accretion disk. In this paper, we generalize the previous relativistic line profile models by including both the black hole spinning effects and the non-axisymmetries of warped accretion disks. Our results show different features from the conventional calculations for either a flat disk around a Kerr black hole or a warped disk around a Schwarzschild black hole by presenting, at the same time, multiple peaks, rather long red tails, and time variations of line profiles with the precession of the disk. We show disk images as seen by a distant observer, which are distorted by the strong gravity. Although we are primarily concerned with the iron K-shell lines in this paper, the calculation is general and is valid for any emission lines produced from a warped accretion disk around a black hole.
Extremal vanishing horizon Kerr-AdS black holes at ultraspinning limit
Noorbakhsh, S. M.; Vahidinia, M. H.
2018-01-01
By utilizing the ultraspinning limit we generate a new class of extremal vanishing horizon (EVH) black holes in odd dimensions ( d ≥ 5). Starting from the general multi-spinning Kerr-AdS metrics, we show the EVH limit commutes with the ultraspinning limit,in which the resulting solutions possess a non-compact but finite area manifold for all ( t, r ≠ r +) = const . slices. We also demonstrate the near horizon geometries of obtained ultraspinning EVH solutions contain an AdS3 throats, where it would be a BTZ black hole in the near EVH cases. The commutativity of the ultraspinning and near horizon limits for EVH solutions is confirmed as well. Furthermore, we discuss only five-dimensional case near the EVH point can be viewed as a super-entropic black hole. We also show that the thermodynamics of the obtained solutions agree with the BTZ black hole. Moreover we investigate the EVH/CFT proposal, demonstrating the entropy of 2d dual CFT and Bekenstein-Hawking entropy are equivalent.
Thermodynamics, stability and Hawking-Page transition of Kerr black holes from Rényi statistics
Czinner, Viktor G.; Iguchi, Hideo
2017-12-01
Thermodynamics of rotating black holes described by the Rényi formula as equilibrium and zeroth law compatible entropy function is investigated. We show that similarly to the standard Boltzmann approach, isolated Kerr black holes are stable with respect to axisymmetric perturbations in the Rényi model. On the other hand, when the black holes are surrounded by a bath of thermal radiation, slowly rotating black holes can also be in stable equilibrium with the heat bath at a fixed temperature, in contrast to the Boltzmann description. For the question of possible phase transitions in the system, we show that a Hawking-Page transition and a first order small black hole/large black hole transition occur, analogous to the picture of rotating black holes in AdS space. These results confirm the similarity between the Rényi-asymptotically flat and Boltzmann-AdS approaches to black hole thermodynamics in the rotating case as well. We derive the relations between the thermodynamic parameters based on this correspondence.
Wang and Yau’s quasi-local energy for an extreme Kerr spacetime
Miller, Warner A.; Ray, Shannon; Wang, Mu-Tao; Yau, Shing-Tung
2018-03-01
There exist constant radial surfaces, S , that may not be globally embeddable in {R}3 for Kerr spacetimes with a>\\sqrt{3}M/2 . To compute the Brown and York (B–Y) quasi-local energy (QLE), one must isometrically embed S into {R}3 . On the other hand, the Wang and Yau (W–Y) QLE embeds S into Minkowski space. In this paper, we examine the W–Y QLE for surfaces that may or may not be globally embeddable in {R}3 . We show that their energy functional, E[τ] , has a critical point at τ=0 for all constant radial surfaces in t=constant hypersurfaces using Boyer–Lindquist coordinates. For τ=0 , the W–Y QLE reduces to the B–Y QLE. To examine the W–Y QLE in these cases, we write the functional explicitly in terms of τ under the assumption that τ is only a function of θ. We then use a Fourier expansion of τ(θ) to explore the values of E[τ(θ)] in the space of coefficients. From our analysis, we discovered an open region of complex values for E[τ(θ)] . We also study the physical properties of the smallest real value of E[τ(θ)] , which lies on the boundary separating real and complex energies.
Magneto-optical Kerr effect studies of copper oxide and cobalt thin films
Energy Technology Data Exchange (ETDEWEB)
Fronk, Michael; Zahn, Dietrich R.T.; Salvan, Georgeta [Chemnitz University of Technology, Chemnitz (Germany); Mueller, Steve; Waechtler, Thomas; Schulz, Stefan E. [Fraunhofer Research Institution for Electronic Nano Systems ENAS, Chemnitz (Germany)
2011-07-01
Copper oxide is supposed to be a model material for tunnel-magneto-resistance (TMR) structures together with cobalt as ferromagnetic electrode. Therefore the magnetic properties of copper oxide itself are of interest and under investigation by various techniques. This contribution presents spectroscopic magneto-optical Kerr effect (MOKE) studies of thin films of this material. The films are produced by atomic layer deposition based on a Cu(I) {beta}-diketonate precursor at a process temperature of 120 C. The copper oxide films turned out to be magneto-optically active both in the spectral range around 2 eV and above 4 eV. Besides the experimental MOKE data the material-intrinsic magneto-optical Voigt constant extracted from optical model calculations are presented. Cobalt, the ferromagnetic counterpart in the TMR structures, was prepared by magnetron sputtering as thin films with different thicknesses. The Voigt constant of Co can be deduced from measurements on thick films (120 nm). It is investigated whether these data can be used to predict the magneto-optical response of thinner Co layers (10 nm).
Enhancement of the transverse Kerr magneto-optic effect by surface magnetoplasma waves
International Nuclear Information System (INIS)
Ferguson, P.E.; Stafsudd, O.M.; Wallis, R.F.
1977-01-01
The results of a theoretical and experimental investigation of the enhancement of the transverse Kerr magneto-optic effect (TKMOE) in a magnetic thin film due to the onset of surface plasma waves (SMPW) are presented. The magnetic thin film was vacuum deposited onto the base of a half-cylinder glass prism. SPW and SMPW induced at the film-air surface can resonant couple to the optical wave propagating parallel to the glass-film surface. In the presence of resonant coupling, the ordinary metallic reflectivity decreases and the normalized reflectivity difference (measure of the TKMOE) increases. Calculations have been made of the reflectivity and the normalized reflectivity difference as a function of angle of incidence for two iron thin films. In addition calculations have been made of the reflectivity and the normalized reflectivity difference as a function of photon energy and angle of incidence for two nickel films of 160A and 200A thickness. The normalized reflectivity difference and reflectivity have been measured for a thick nickel film and a thin nickel film (160A). An enhancement of the normalized reflectivity difference of 3x has been found. (Auth.)
Thermodynamics, stability and Hawking-Page transition of Kerr black holes from Renyi statistics
Energy Technology Data Exchange (ETDEWEB)
Czinner, Viktor G. [University of Lisbon, Multidisciplinary Center for Astrophysics and Department of Physics, Instituto Superior Tecnico, Lisboa (Portugal); HAS Wigner Research Centre for Physics, Budapest (Hungary); Iguchi, Hideo [Nihon University, Laboratory of Physics, College of Science and Technology, Funabashi, Chiba (Japan)
2017-12-15
Thermodynamics of rotating black holes described by the Renyi formula as equilibrium and zeroth law compatible entropy function is investigated. We show that similarly to the standard Boltzmann approach, isolated Kerr black holes are stable with respect to axisymmetric perturbations in the Renyi model. On the other hand, when the black holes are surrounded by a bath of thermal radiation, slowly rotating black holes can also be in stable equilibrium with the heat bath at a fixed temperature, in contrast to the Boltzmann description. For the question of possible phase transitions in the system, we show that a Hawking-Page transition and a first order small black hole/large black hole transition occur, analogous to the picture of rotating black holes in AdS space. These results confirm the similarity between the Renyi-asymptotically flat and Boltzmann-AdS approaches to black hole thermodynamics in the rotating case as well. We derive the relations between the thermodynamic parameters based on this correspondence. (orig.)
Exploring DC-Kerr effect of impurity doped quantum dots under the aegis of noise
Arif, Sk. Md.; Bera, Aindrila; Ghosh, Anuja; Ghosh, Manas
2018-02-01
Present study performs an extensive exploration of the profiles of DC-Kerr effect (DCKE) of doped GaAs quantum dot (QD) under the control of Gaussian white noise. A large number of important physical parameters have been varied over a range and the resultant changes in the DCKE profiles have been thoroughly analyzed. The said physical parameters comprise of electric field, magnetic field, confinement potential, dopant location, dopant potential, noise strength, aluminium concentration (only for Alx Ga1 - x As alloy QD), carrier density, relaxation time, position-dependent effective mass (PDEM), position-dependent dielectric screening function (PDDSF), anisotropy, hydrostatic pressure (HP) and temperature. The particular physical quantity being varied, presence of noise and its pathway of application, in combination, lead to emergence of diverse features in the DCKE profiles. As a technologically significant aspect we often find maximization of DCKE for some typical combinations as mentioned above. Presence of multiplicative noise, in general, causes greater shift and greater augmentation of DCKE profiles from a noise-free condition than its additive counterpart. The outcomes of the study indicate ample scope of tailoring DCKE of doped QD systems in presence of noise by minute adjustment of several control parameters.
Soft-x-ray magneto-optical Kerr effect and element-specific hysteresis measurement
Energy Technology Data Exchange (ETDEWEB)
Kortright, J.B.; Rice, M. [Lawrence Berkeley National Lab., CA (United States)
1997-04-01
Interest in the utilization of x-ray magneto-optical properties to provide element-specific magnetic information, combined with recent development of tunable linear polarizers for spectroscopic polarization measurement, have led the authors to the study of magneto-optical rotation (MOR) near core levels of magnetic atoms in magnetic multilayer and alloy films. Their initial observation of Faraday rotation (in transmission) demonstrated that for Fe MOR is easily measured and is larger at its L{sub 3} resonance than in the near-visible spectral regions. This work also demonstrated that the spectroscopic behavior of the MOR signal in transmission, resulting from the differential reaction of left- and right-circular components of a linearly polarized beam, is related to the magnetic circular dichroism (MCD), or differential absorption, as expected by a Kramers-Kronig transformation. Thus MCD measurements using circular polarization and MOR measurements using linear polarization can provide complementary, and in some cases equivalent, information. On beamline 6.3.2 the authors have begun to investigate soft x-ray MOR in the reflection geometry, the x-ray magneto-optic Kerr effect (XMOKE). Early measurements have demonstrated the ability to measure element-specific hysteresis loops and large rotations compared to analogous near-visible measurements. The authors are investigating the spectral dependence of the XMOKE signal, and have initiated systematic materials studies of sputter-deposited films of Fe, Fe{sub x}Cr{sub 1{minus}x} alloys, and Fe/Cr multilayers.
Linear mode stability of the Kerr-Newman black hole and its quasinormal modes.
Dias, Óscar J C; Godazgar, Mahdi; Santos, Jorge E
2015-04-17
We provide strong evidence that, up to 99.999% of extremality, Kerr-Newman black holes (KNBHs) are linear mode stable within Einstein-Maxwell theory. We derive and solve, numerically, a coupled system of two partial differential equations for two gauge invariant fields that describe the most general linear perturbations of a KNBH. We determine the quasinormal mode (QNM) spectrum of the KNBH as a function of its three parameters and find no unstable modes. In addition, we find that the lowest radial overtone QNMs that are connected continuously to the gravitational ℓ=m=2 Schwarzschild QNM dominate the spectrum for all values of the parameter space (m is the azimuthal number of the wave function and ℓ measures the number of nodes along the polar direction). Furthermore, the (lowest radial overtone) QNMs with ℓ=m approach Reω=mΩH(ext) and Imω=0 at extremality; this is a universal property for any field of arbitrary spin |s|≤2 propagating on a KNBH background (ω is the wave frequency and ΩH(ext) the black hole angular velocity at extremality). We compare our results with available perturbative results in the small charge or small rotation regimes and find good agreement.
International Nuclear Information System (INIS)
Pinotti, E.; Brenna, M.; Puppin, E.
2008-01-01
In magneto-optical Kerr measurements of the Barkhausen noise, a magnetization jump ΔM due to a domain reversal produces a variation ΔI of the intensity of a laser beam reflected by the sample, which is the physical quantity actually measured. Due to the non-uniform beam intensity profile, the magnitude of ΔI depends both on ΔM and on its position on the laser spot. This could distort the statistical distribution p(ΔI) of the measured ΔI with respect to the true distribution p(ΔM) of the magnetization jumps ΔM. In this work the exact relationship between the two distributions is derived in a general form, which will be applied to some possible beam profiles. It will be shown that in most cases the usual Gaussian beam produces a negligible statistical distortion. Moreover, for small ΔI the noise of the experimental setup can also distort the statistical distribution p(ΔI), by erroneously rejecting small ΔI as noise. This effect has been calculated for white noise, and it will be shown that it is relatively small but not totally negligible as the measured ΔI approaches the detection limit
Asymptotic symmetries on the Kerr-Newman horizon without the anomaly of diffeomorphism invariance
International Nuclear Information System (INIS)
Koga, Jun-ichirou
2008-01-01
We analyze asymptotic symmetries on the Killing horizon of the four-dimensional Kerr-Newman black hole. We first derive the asymptotic Killing vectors on the Killing horizon, which describe the asymptotic symmetries, and find that the general form of these asymptotic Killing vectors is the universal one possessed by arbitrary Killing horizons. We then construct the phase space associated with the asymptotic symmetries. It is shown that the phase space of an extreme black hole either has the size comparable with a non-extreme black hole, or is small enough to exclude degeneracy, depending on whether or not the global structure of a Killing horizon particular to an extreme black hole is respected. We also show that the classical central charge in the Poisson brackets algebra of these asymptotic symmetries vanishes, which implies that there is not an anomaly of diffeomorphism invariance. By taking into account other results in the literature, we argue that the vanishing central charge on a black hole horizon, in an effective theory, looks consistent with the thermal feature of a black hole. We furthermore argue that the vanishing central charge implies that there are sufficiently many classical configurations that constitute a single macroscopic state, while these configurations are distinguished physically
Multichannel nonlinear distortion compensation using optical phase conjugation in a silicon nanowire
DEFF Research Database (Denmark)
Vukovic, Dragana; Schoerder, Jochen; Da Ros, Francesco
2015-01-01
We experimentally demonstrate compensation of nonlinear distortion caused by the Kerr effect in a 3 x 32-Gbaud quadrature phase-shift keying (QPSK) wavelength-division multiplexing (WDM) transmission system. We use optical phase conjugation (OPC) produced by four-wave mixing (FWM) in a 7-mm long...... silicon nanowire. A clear improvement in Q-factor is shown after 800-km transmission with high span input power when comparing the system with and without the optical phase conjugation module. The influence of OSNR degradation introduced by the silicon nanowire is analysed by comparing transmission...... systems of three different lengths. This is the first demonstration of nonlinear compensation using a silicon nanowire. (C)2015 Optical Society of America...
Giant magnetorefractive effect in La{sub 0.7}Ca{sub 0.3}MnO{sub 3} films
Energy Technology Data Exchange (ETDEWEB)
Granovskii, A. B., E-mail: granov@magn.ru [Moscow State University (Russian Federation); Sukhorukov, Yu. P., E-mail: suhorukov@imp.uran.ru; Telegin, A. V.; Bessonov, V. D. [Russian Academy of Sciences, Institute of Metal Physics, Ural Branch (Russian Federation); Gan' shina, E. A.; Kaul' , A. R.; Korsakov, I. E.; Gorbenko, O. Yu. [Moscow State University (Russian Federation); Gonzalez, J. [Universidad del Pais Vasco, Departamento Fisica de Materiales, Facultad de Quimica (Spain)
2011-01-15
Complex experimental investigations of the structural, optical, and magneto-optical properties (magnetotransmission, magnetoreflection, and transversal Kerr effect, as well as the magnetoresistance, of La{sub 0.7}Ca{sub 0.3}MnO{sub 3} epitaxial films indicate that magnetoreflection and magnetotransmission in manganite films can reach giant values and depend strongly on the magnetic and charge homogeneity of the films, their thickness, and spectral range under investigation. It has been shown that the optical enhancement of the magnetorefractive effect occurs in thin films as compared to manganite crystals. In the region of the minimum of the reflectance near the first phonon band, the resonance-like magnetorefractive effect has been observed, which is accompanied by change of the sign of the magnetoreflection. A model based on the theory of the magnetorefractive effect has been proposed to qualitatively explain this behavior.
Chatterjee, Roshmi; Basu, Mousumi
2018-02-01
The well known time transformation method is used here to derive the temporal and spectral electric field distribution at the output end of a multilayer waveguide which consists of different layers of Kerr nonlinear media. A highly nonlinear CS 3-68 glass is considered as one of the materials of the waveguide which mainly comprises of different chalcogenide glass layers. The results indicate that there is sufficient time delay as well as frequency shift between the input and output pulses which is associated with the phenomenon of adiabatic wavelength conversion (AWC). Depending on different arrangements of materials, the time delay and frequency shift can be changed. As a result an input pulse in visible green region can be blue-shifted or red-shifted according to the choices of refractive index of the non-dispersive Kerr nonlinear media. The results show that under certain conditions the input pulse is broadened or compressed for different combinations of materials. This process of AWC also includes the variation of temporal and spectral phase, time delay, temporal peak power etc. For different input pulse shapes the change in time delay is also presented. The study may be useful to find applications of AWC in optical resonators or optical signal processing to be applicable to different photonic devices.
Giant Leiomyoma of the Oesophagus
Kandasamy, Dhamodaran; Kannan, Sujatha; Samuel, Vasundaran
2017-01-01
Leiomyomas are rare benign tumours of the oesophagus that remain silent in more than 50% of the cases. Giant leiomyomas measuring more than 5 cm are very rare. A 47-year-old female presented with chest pain, cough and dysphagia for two months. Imaging studies were indicative of a 12.1x11.9 cm mass lesion in the distal oesophagus, CT guided biopsy confirmed leiomyoma. The patient being taken up for surgery was found to have a 20x19x17 cm irregular lobulated and encapsulated mass lesion arising from distal oesophagus encapsulating submucosally. En bloc resection of the tumour along with distal oesophagus with a clearance of 4 cm above and below the oesophagogastric junction was done followed by gastro-oesophageal anastomosis. Histopathologically, leiomyoma was confirmed. The patient had a smooth postoperative recovery. PMID:28571208
Giant trichobezoar mimicking gastric tumour
International Nuclear Information System (INIS)
Ali, S.A.; Soomro, A.G.; Jarwar, M.; Memon, A.S.; Siddiqui, A.J.
2012-01-01
We present a case of giant gastric trichobezoar retrieved through a long gastrotomy in a 40 years old married women from rural Sindh with unreported psychological disturbance. Trichobezoar almost exclusively occur in females with an underlying psychiatric disorder. It has an insidious development of symptoms which accounts for its delayed presentation and large size at the time of diagnosis. They are associated with trichophagia (habit of compulsive hair eating) and are usually diagnosed on CT Scans or upper GI Endoscopy. They can give rise to complications like gastro-duodenal ulceration, haemorrhage, perforation, peritonitis or obstruction with a high rate of mortality. The treatment is endoscopic, laparoscopic or surgical removal and usually followed by psychiatric opinion. (author)
Multipole giant resonances in highly excited nuclei
International Nuclear Information System (INIS)
Xia Keding; Cai Yanhuang
1989-01-01
The isoscalar giant surface resonance and giant dipole resonance in highly excited nuclei are discussed. Excitation energies of the giant modes in 208 Pb are calculated in a simplified model, using the concept of energy wieghted sum rule (EWSR), and the extended Thomas-Fermi approximation at the finite temperature is employed to describe the finite temperature is employed to describe the finite temperature equilibrium state. It is shown that EWSR and the energy of the resonance depend only weakly on temperature in the system. This weak dependence is analysed
Revised Stroemgren metallicity calibration for red giants
Hilker, Michael
1999-01-01
A new calibration of the Stroemgren (b-y),m_1 diagram in terms of iron abundance of red giants is presented. This calibration is based on a homogeneous sample of giants in the globular clusters omega Centauri, M22, and M55 as well as field giants from the list of Anthony-Twarog & Twarog (1998). Towards high metallicities, the new calibration is connected to a previous calibration by Grebel & Richtler (1992), which was unsatisfactory for iron abudances lower than -1.0 dex. The revised calibrat...
Giant flexoelectricity in polyvinylidene fluoride films
Energy Technology Data Exchange (ETDEWEB)
Baskaran, Sivapalan; Ramachandran, Narayanan; He Xiangtong; Thiruvannamalai, Sankar; Lee, Ho Joon; Heo, Hyun [Department of Mechanical and Aerospace Engineering, State University of New York, Buffalo, NY 14260 (United States); Chen Qin [GE Global Research Center, 1 Research Circle, Niskayuna, NY 12309 (United States); Fu, John Y., E-mail: youweifu@buffalo.ed [Department of Mechanical and Aerospace Engineering, State University of New York, Buffalo, NY 14260 (United States)
2011-05-16
Recent studies have shown that giant flexoelectricity may exist in certain elastomers with bent-core molecular structures, which contradicts the previous theoretical estimation that the flexoelectric coupling is small in those materials. In this Letter, we report an analogous phenomenon, i.e., the giant direct flexoelectric effect, observed in a polyvinylidene fluoride (PVDF) film. Our experimental studies indicate that such an enhanced flexoelectric effect might be induced by the interaction between the energy couplings of the apolar and the polar molecular structures of the polymer film under elastic deformation. - Highlights: Polyvinylidene fluoride (PVDF) film with not fully crystallized {alpha}- and {beta}-phases. Flexoelectric measurement. Giant direct flexoelectric effect in PVDF.
Wave propagation in ordered, disordered, and nonlinear photonic band gap materials
Energy Technology Data Exchange (ETDEWEB)
Lidorikis, Elefterios [Iowa State Univ., Ames, IA (United States)
1999-12-10
Photonic band gap materials are artificial dielectric structures that give the promise of molding and controlling the flow of optical light the same way semiconductors mold and control the electric current flow. In this dissertation the author studied two areas of photonic band gap materials. The first area is focused on the properties of one-dimensional PBG materials doped with Kerr-type nonlinear material, while, the second area is focused on the mechanisms responsible for the gap formation as well as other properties of two-dimensional PBG materials. He first studied, in Chapter 2, the general adequacy of an approximate structure model in which the nonlinearity is assumed to be concentrated in equally-spaced very thin layers, or 6-functions, while the rest of the space is linear. This model had been used before, but its range of validity and the physical reasons for its limitations were not quite clear yet. He performed an extensive examination of many aspects of the model's nonlinear response and comparison against more realistic models with finite-width nonlinear layers, and found that the d-function model is quite adequate, capturing the essential features in the transmission characteristics. The author found one exception, coming from the deficiency of processing a rigid bottom band edge, i.e. the upper edge of the gaps is always independent of the refraction index contrast. This causes the model to miss-predict that there are no soliton solutions for a positive Kerr-coefficient, something known to be untrue.
Fatal canine distemper virus infection of giant pandas in China
Feng, Na; Yu, Yicong; Wang, Tiecheng; Wilker, Peter; Wang, Jianzhong; Li, Yuanguo; Sun, Zhe; Gao, Yuwei; Xia, Xianzhu
2016-01-01
We report an outbreak of canine distemper virus (CDV) infection among endangered giant pandas (Ailuropoda melanoleuca). Five of six CDV infected giant pandas died. The surviving giant panda was previously vaccinated against CDV. Genomic sequencing of CDV isolated from one of the infected pandas (giant panda/SX/2014) suggests it belongs to the Asia-1 cluster. The hemagglutinin protein of the isolated virus and virus sequenced from lung samples originating from deceased giant pandas all possess...
Linderman, Marc Alan
We examined an approach to classifying understory bamboo, the staple food of the giant panda (Ailuropoda melanoleuca), from remote sensing imagery in the Wolong Nature Reserve, China. We also used these data to estimate the landscape-scale distribution of giant panda habitat, and model the human effects on forest cover and the spatio-temporal dynamics of bamboo and the resulting implications for giant panda habitat. The spatial distribution of understory bamboo was mapped using an artificial neural network and leaf-on remote sensing data. Training on a limited set of ground truth data and using widely available Landsat TM data as input, a non-linear artificial neural network achieved a classification accuracy of 80% despite the presence of co-occurring mid-story and understory vegetation. Using information on the spatial distribution of bamboo in Wolong, we compared the results of giant panda habitat analyses with and without bamboo information. Total amount of habitat decreased by 29--56% and overall habitat patch size decreased by 16--48% after bamboo information was incorporated into the analyses. The decreases in the quantity of panda habitat and increases in habitat fragmentation resulted in decreases of 41--60% in carrying capacity. Using a spatio-temporal model of bamboo dynamics and human activities, we found that local fuelwood collection and household creation will likely reduce secondary habitat relied upon by pandas. Human impacts would likely contribute up to an additional 16% loss of habitat. Furthermore, these impacts primarily occur in the habitat relied upon by giant pandas during past bamboo die-offs. Decreased total area of habitat and increased fragmentation from human activities will likely make giant pandas increasingly sensitive to natural disturbances such as cyclical bamboo die-offs. Our studies suggest that it is necessary to further examine approaches to monitor understory vegetation and incorporate understory information into wildlife
Giant Plagioclase Basalts, eruption rate versus time
Indian Academy of Sciences (India)
Home; Journals; Journal of Earth System Science; Volume 111; Issue 4. Giant Plagioclase Basalts, eruption rate versus time: Response to Sheth's comments and some additional thoughts. Gautam Sen. Volume 111 Issue 4 December 2002 pp 487-488 ...
Recurrent giant juvenile fibroadenomas with hemihypertrophy.
Tantrige, Priyan Maleuwe; Hassanally, Delilah
2011-01-01
Giant juvenile fibroadenomas in patients with hemihypertrophy are exceptionally rare. We present a very interesting case of a 13 year old girl with hemihypertrophy of the left side presenting with recurrent giant juvenile fibroadenomas of the left breast. The giant fibroadenomas occurred twice in the left breast over two years. The first had a diameter of 12 cm and was excised through an inframammary incision. The second occurred a year later, had a diameter of 11 cm, and was associated with three smaller fibroadenomas. These lesions were removed through a single periareolar incision. The procedures were complicated by keloid scarring but the results were improved with steroid impregnated tape dressing and local methylprednisolone injection. This report adds to our experience in managing patients with recurrent giant juvenile fibroadenomas complicated by hemihypertrophy and raises awareness to anticipate keloid scarring.
Giant Omental Lipoma in a Child
International Nuclear Information System (INIS)
Chaudhary, Vikas; Narula, Mahender Kaur; Anand, Rama; Gupta, Isha; Kaur, Gurmeen; Kalra, Kanika
2011-01-01
Omental lipomas are extremely rare tumors of childhood. We report a case of solitary giant lipoma of the omentum in a child, successfully managed by complete excision, without any recurrence on follow-up study
AFSC/ABL: Female Giant Grenadier maturity
National Oceanic and Atmospheric Administration, Department of Commerce — Giant grenadiers Albatrossia pectoralis are caught as bycatch in deep-sea commercial fisheries in relatively large numbers. The population appears to be stable,...
Enhanced recovery after giant ventral hernia repair
DEFF Research Database (Denmark)
Jensen, K K; Brøndum, T L; Harling, H.
2016-01-01
PURPOSE: Giant ventral hernia repair is associated with a high risk of postoperative morbidity and prolonged length of stay (LOS). Enhanced recovery (ERAS) measures have proved to lead to decreased morbidity and LOS after various surgical procedures, but never after giant hernia repair. The current...... study prospectively examined the results of implementation of an ERAS pathway including high-dose preoperative glucocorticoid, and compared the outcome with patients previously treated according to standard care (SC). METHODS: Consecutive patients who underwent giant ventral hernia repair were included......-dose glucocorticoid may lead to low scores of pain, fatigue and nausea after giant ventral hernia repair with reduced LOS compared with patients treated according to SC....
Red giants as precursors of planetary nebulae
International Nuclear Information System (INIS)
Renzini, A.
1981-01-01
It is generally accepted that Planetary Nebulae are produced by asymptotic giant-branch stars. Therefore, several properties of planetary nebulae are discussed in the framework of the current theory of stellar evolution. (Auth.)
Blood Lead Levels in Captive Giant Pandas.
Wintle, Nathan J P; Martin-Wintle, Meghan S; Zhou, Xiaoping; Zhang, Hemin
2018-01-01
Fifteen giant pandas (Ailuropoda melanoleuca) from the Chinese Conservation and Research Center for the Giant Panda (CCRCGP) in Bifengxia, Sichuan, China were analyzed for blood lead concentrations (Pb-B) during the 2017 breeding season. Thirteen of the 15 bears showed Pb-B below the method detection limit (MDL) of 3.3 µg/dL. The two remaining bears, although above the MDL, contained very low concentrations of lead of 3.9 and 4.5 µg/dL. All 15 giant pandas in this analysis had Pb-B concentrations that were within normal background concentrations for mammals in uncontaminated environments. For a threatened species, whose native country is plagued by reports of extremely high air pollution, our findings suggest that giant pandas at the CCRCGP are not absorbing lead at concentrations that would adversely affect their health.
Innate predator recognition in giant pandas.
Du, Yiping; Huang, Yan; Zhang, Hemin; Li, Desheng; Yang, Bo; Wei, Ming; Zhou, Yingmin; Liu, Yang
2012-02-01
Innate predator recognition confers a survival advantage to prey animals. We investigate whether giant pandas exhibit innate predator recognition. We analyzed behavioral responses of 56 naive adult captive giant pandas (Ailuropoda melanoleuca), to urine from predators and non-predators and water control. Giant pandas performed more chemosensory investigation and displayed flehmen behaviors more frequently in response to predator urine compared to both non-predator urine and water control. Subjects also displayed certain defensive behaviors, as indicated by vigilance, and in certain cases, fleeing behaviors. Our results suggest that there is an innate component to predator recognition in captive giant pandas, although such recognition was only slight to moderate. These results have implications that may be applicable to the conservation and reintroduction of this endangered species.
Ulku, Huseyin Arda
2014-07-06
Effects of material nonlinearities on electromagnetic field interactions become dominant as field amplitudes increase. A typical example is observed in plasmonics, where highly localized fields “activate” Kerr nonlinearities. Naturally, time domain solvers are the method of choice when it comes simulating these nonlinear effects. Oftentimes, finite difference time domain (FDTD) method is used for this purpose. This is simply due to the fact that explicitness of the FDTD renders the implementation easier and the material nonlinearity can be easily accounted for using an auxiliary differential equation (J.H. Green and A. Taflove, Opt. Express, 14(18), 8305-8310, 2006). On the other hand, explicit marching on-in-time (MOT)-based time domain integral equation (TDIE) solvers have never been used for the same purpose even though they offer several advantages over FDTD (E. Michielssen, et al., ECCOMAS CFD, The Netherlands, Sep. 5-8, 2006). This is because explicit MOT solvers have never been stabilized until not so long ago. Recently an explicit but stable MOT scheme has been proposed for solving the time domain surface magnetic field integral equation (H.A. Ulku, et al., IEEE Trans. Antennas Propag., 61(8), 4120-4131, 2013) and later it has been extended for the time domain volume electric field integral equation (TDVEFIE) (S. B. Sayed, et al., Pr. Electromagn. Res. S., 378, Stockholm, 2013). This explicit MOT scheme uses predictor-corrector updates together with successive over relaxation during time marching to stabilize the solution even when time step is as large as in the implicit counterpart. In this work, an explicit MOT-TDVEFIE solver is proposed for analyzing electromagnetic wave interactions on scatterers exhibiting Kerr nonlinearity. Nonlinearity is accounted for using the constitutive relation between the electric field intensity and flux density. Then, this relation and the TDVEFIE are discretized together by expanding the intensity and flux - sing half
The cytology of giant solitary trichoepithelioma
Directory of Open Access Journals (Sweden)
Krishnamurthy Jayashree
2010-01-01
Full Text Available Giant solitary trichoepithelioma (GST is a rare trichogenic tumor, which may present as a pigmented lesion. An 80-year-old man was diagnosed to have giant solitary trichoepithelioma on fine-needle aspiration cytology. The cytological findings represented the histological features. The recognition of GST is important because of its close resemblance to basal cell carcinoma and other skin adnexal tumors - clinically, cytologically and histologically.
Giant Planet Interior Structure and Thermal Evolution
Fortney, Jonathan J.; Baraffe, Isabelle; Militzer, Burkhard
2009-01-01
We discuss the interior structure and composition of giant planets, and how this structure changes as these planets cool and contract over time. Here we define giant planets as those that have an observable hydrogen-helium envelope, which includes Jupiter-like planets, which are predominantly H/He gas, and Neptune-like planets which are predominantly composed of elements heavier than H/He. We describe the equations of state of planetary materials and the construction of static structural mode...
Giant rhinophyma: Excision with coblation assisted surgery
Directory of Open Access Journals (Sweden)
Caner Sahin
2014-01-01
Full Text Available An 83-year-old man presented with an unusually severe case of rhinophyma. Giant rhinopyhma is very rare in literature. The giant lesion was widely excised using sharp surgical incision and coblation assisted surgery. Using direct coblation to the nasal dorsum may cause edema in the surrounding tissue. There was minimal edema in surrounding tissue using this technique. A full thickness-skin graft was applied after excision. Cosmetic and functional postoperative results were satisfactory.
Swiss roll operation for giant fibroadenoma.
Soomro, Saleem A; Memon, Sohail A; Mohammad, Noor; Maher, Mumtaz
2009-01-01
Fibroadenoma 5 cm or more is called giant fibroadenoma. Giant fibroadenoma can distort the shape of breast and causes asymmetry, so it should be excised. There are several techniques for excision of giant fibroadenoma. In our technique we remove them through cosmetically acceptable circumareolar incision to maintain the shape and symmetry of breast. The objectives were to assess the cosmetic results of Swiss roll operation for giant fibroadenoma. The study was conducted for six years from January, 2002 to December, 2007. Seventy patients of giant fibroadenoma were included in this study. They were diagnosed on history and clinical examination supported by ultrasound and postoperative histopathological examination. Data were collected from outpatient department and operation theatre. Swiss roll operation was performed under general anaesthesia. Mean tumor size was 6.38 cm. Three cm and 4 cm incisions were used for tumour 6 cm in size respectively. Skin closed with Vicryl 3/0 subcuticular stitches. Sixteen out of 70 patients had no scar while others hadminimal scar. All patients had normal shape and symmetry of breast. On histopathology fibroadenoma was confirmed. Giant fibroadenoma should be removed through cosmetically acceptable cicumareolar incision especially in unmarried young females who have small breast. Swiss-roll operation is superior in maintaining the shape and symmetry of breast. No major complication was found in our series except seroma formation in 10 patients.
Macroscopic description of isoscalar giant multipole resonances
International Nuclear Information System (INIS)
Nix, J.R.; Sierk, A.J.
1980-01-01
On the basis of a simple macroscopic model, we calculate the isoscalar giant-resonance energy as a function of mass number and multipole degree. The restoring force is determined from the distortion of the Fermi surface, and the inertia is determined for the incompressible, irrotational flow of nucleons with unit effective mass. With no adjustable parameters, the resulting closed expression reproduces correctly the available experimental data, namely the magnitude and dependence upon mass number of the giant quadrupole energy and the magnitude of the giant octupole energy for 208 Pb. We also calculate the isoscalar giant-resonance width as a function of mass number and multipole degree for various macroscopic damping mechanisms, including two-body viscosity, one-body dissipation, and modified one-body dissipation. None of these damping mechanisms reproduces correctly all features of the available experimental data, namely the magnitude and dependence upon mass number of the giant quadrupole width and the magnitude of the giant octupole width for 208 Pb
Algorithms and Programs for Strong Gravitational Lensing In Kerr Space-time Including Polarization
Chen, Bin; Kantowski, Ronald; Dai, Xinyu; Baron, Eddie; Maddumage, Prasad
2015-05-01
Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of the central supermassive black hole. For distances within a few gravitational radii, light paths are strongly bent by the strong gravity field of the central black hole. If the central black hole has nonzero angular momentum (spin), then a photon’s polarization plane will be rotated by the gravitational Faraday effect. The observed X-ray flux and polarization will then be influenced significantly by the strong gravity field near the source. Consequently, linear gravitational lensing theory is inadequate for such extreme circumstances. We present simple algorithms computing the strong lensing effects of Kerr black holes, including the effects on polarization. Our algorithms are realized in a program “KERTAP” in two versions: MATLAB and Python. The key ingredients of KERTAP are a graphic user interface, a backward ray-tracing algorithm, a polarization propagator dealing with gravitational Faraday rotation, and algorithms computing observables such as flux magnification and polarization angles. Our algorithms can be easily realized in other programming languages such as FORTRAN, C, and C++. The MATLAB version of KERTAP is parallelized using the MATLAB Parallel Computing Toolbox and the Distributed Computing Server. The Python code was sped up using Cython and supports full implementation of MPI using the “mpi4py” package. As an example, we investigate the inclination angle dependence of the observed polarization and the strong lensing magnification of AGN X-ray emission. We conclude that it is possible to perform complex numerical-relativity related computations using interpreted languages such as MATLAB and Python.
ALGORITHMS AND PROGRAMS FOR STRONG GRAVITATIONAL LENSING IN KERR SPACE-TIME INCLUDING POLARIZATION
International Nuclear Information System (INIS)
Chen, Bin; Maddumage, Prasad; Kantowski, Ronald; Dai, Xinyu; Baron, Eddie
2015-01-01
Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of the central supermassive black hole. For distances within a few gravitational radii, light paths are strongly bent by the strong gravity field of the central black hole. If the central black hole has nonzero angular momentum (spin), then a photon’s polarization plane will be rotated by the gravitational Faraday effect. The observed X-ray flux and polarization will then be influenced significantly by the strong gravity field near the source. Consequently, linear gravitational lensing theory is inadequate for such extreme circumstances. We present simple algorithms computing the strong lensing effects of Kerr black holes, including the effects on polarization. Our algorithms are realized in a program “KERTAP” in two versions: MATLAB and Python. The key ingredients of KERTAP are a graphic user interface, a backward ray-tracing algorithm, a polarization propagator dealing with gravitational Faraday rotation, and algorithms computing observables such as flux magnification and polarization angles. Our algorithms can be easily realized in other programming languages such as FORTRAN, C, and C++. The MATLAB version of KERTAP is parallelized using the MATLAB Parallel Computing Toolbox and the Distributed Computing Server. The Python code was sped up using Cython and supports full implementation of MPI using the “mpi4py” package. As an example, we investigate the inclination angle dependence of the observed polarization and the strong lensing magnification of AGN X-ray emission. We conclude that it is possible to perform complex numerical-relativity related computations using interpreted languages such as MATLAB and Python
Circular and noncircular nearly horizon-skimming orbits in Kerr spacetimes
Barausse, Enrico; Hughes, Scott A.; Rezzolla, Luciano
2007-08-01
We have performed a detailed analysis of orbital motion in the vicinity of a nearly extremal Kerr black hole. For very rapidly rotating black holes—spin parameter a≡J/M>0.9524M—we have found a class of very strong-field eccentric orbits whose orbital angular momentum Lz increases with the orbit’s inclination with respect to the equatorial plane, while keeping latus rectum and eccentricity fixed. This behavior is in contrast with Newtonian intuition, and is in fact opposite to the normal behavior of black hole orbits. Such behavior was noted previously for circular orbits; since it only applies to orbits very close to the black hole, they were named “nearly horizon-skimming orbits.” Our current analysis generalizes this result, mapping out the full generic (inclined and eccentric) family of nearly horizon-skimming orbits. The earlier work on circular orbits reported that, under gravitational radiation emission, nearly horizon-skimming orbits exhibit unusual inspiral, tending to evolve to smaller orbit inclination, toward prograde equatorial configuration. Normal orbits, by contrast, always demonstrate slowly growing orbit inclination—orbits evolve toward the retrograde equatorial configuration. Using up-to-date Teukolsky-based fluxes, we have concluded that the earlier result was incorrect—all circular orbits, including nearly horizon-skimming ones, exhibit growing orbit inclination under radiative backreaction. Using kludge fluxes based on a Post-Newtonian expansion corrected with fits to circular and to equatorial Teukolsky-based fluxes, we argue that the inclination grows also for eccentric nearly horizon-skimming orbits. We also find that the inclination change is, in any case, very small. As such, we conclude that these orbits are not likely to have a clear and peculiar imprint on the gravitational waveforms expected to be measured by the space-based detector LISA.
Ooi, Kelvin J. A.; Tan, Dawn T. H.
2017-10-01
The rapid development of graphene has opened up exciting new fields in graphene plasmonics and nonlinear optics. Graphene's unique two-dimensional band structure provides extraordinary linear and nonlinear optical properties, which have led to extreme optical confinement in graphene plasmonics and ultrahigh nonlinear optical coefficients, respectively. The synergy between graphene's linear and nonlinear optical properties gave rise to nonlinear graphene plasmonics, which greatly augments graphene-based nonlinear device performance beyond a billion-fold. This nascent field of research will eventually find far-reaching revolutionary technological applications that require device miniaturization, low power consumption and a broad range of operating wavelengths approaching the far-infrared, such as optical computing, medical instrumentation and security applications.
Directory of Open Access Journals (Sweden)
Wei Khim Ng
2009-02-01
Full Text Available We construct nonlinear extensions of Dirac's relativistic electron equation that preserve its other desirable properties such as locality, separability, conservation of probability and Poincaré invariance. We determine the constraints that the nonlinear term must obey and classify the resultant non-polynomial nonlinearities in a double expansion in the degree of nonlinearity and number of derivatives. We give explicit examples of such nonlinear equations, studying their discrete symmetries and other properties. Motivated by some previously suggested applications we then consider nonlinear terms that simultaneously violate Lorentz covariance and again study various explicit examples. We contrast our equations and construction procedure with others in the literature and also show that our equations are not gauge equivalent to the linear Dirac equation. Finally we outline various physical applications for these equations.
Optical Beams in Nonlocal Nonlinear Media
DEFF Research Database (Denmark)
Królikowski, W.; Bang, Ole; Wyller, J.
2003-01-01
We discuss propagation of optical beams in nonlocal Kerr-like media with the nonlocality of general form. We study the effect of nonlocality on modulational instability of the plane wave fronts, collapse of finite beams and formation of spatial solitons.......We discuss propagation of optical beams in nonlocal Kerr-like media with the nonlocality of general form. We study the effect of nonlocality on modulational instability of the plane wave fronts, collapse of finite beams and formation of spatial solitons....
A magnetic betelgeuse? Numerical simulations of non-linear dynamo action
DEFF Research Database (Denmark)
Dorch, S. B. F.
2004-01-01
Betelgeuse is an example of a cool super-giant displaying brightness fluctuations and irregular surface structures. Simulations by Freytag et al. (2002) of the convective envelope of the star have shown that the fluctuations in the star's luminosity may be caused by giant cell convection. A related...... question regarding the nature of Betelgeuse and supergiants in general is whether these stars may be magnetically active. If so, that may in turn also contribute to their variability. By performing detailed numerical simulations, I find that both linear kinematic and non-linear dynamo action are possible...
Uraltseva, N N
1995-01-01
This collection focuses on nonlinear problems in partial differential equations. Most of the papers are based on lectures presented at the seminar on partial differential equations and mathematical physics at St. Petersburg University. Among the topics explored are the existence and properties of solutions of various classes of nonlinear evolution equations, nonlinear imbedding theorems, bifurcations of solutions, and equations of mathematical physics (Navier-Stokes type equations and the nonlinear Schrödinger equation). The book will be useful to researchers and graduate students working in p
Kono, Mitsuo
2010-01-01
A nonlinearity is one of the most important notions in modern physics. A plasma is rich in nonlinearities and provides a variety of behaviors inherent to instabilities, coherent wave structures and turbulence. The book covers the basic concepts and mathematical methods, necessary to comprehend nonlinear problems widely encountered in contemporary plasmas, but also in other fields of physics and current research on self-organized structures and magnetized plasma turbulence. The analyses make use of strongly nonlinear models solved by analytical techniques backed by extensive simulations and available experiments. The text is written for senior undergraduates, graduate students, lecturers and researchers in laboratory, space and fusion plasmas.
Nonlinear optics at interfaces
International Nuclear Information System (INIS)
Chen, C.K.
1980-12-01
Two aspects of surface nonlinear optics are explored in this thesis. The first part is a theoretical and experimental study of nonlinear intraction of surface plasmons and bulk photons at metal-dielectric interfaces. The second part is a demonstration and study of surface enhanced second harmonic generation at rough metal surfaces. A general formulation for nonlinear interaction of surface plasmons at metal-dielectric interfaces is presented and applied to both second and third order nonlinear processes. Experimental results for coherent second and third harmonic generation by surface plasmons and surface coherent antiStokes Raman spectroscopy (CARS) are shown to be in good agreement with the theory