Search for the two-phonon octupole vibrational state in {sup 208}Pb
Energy Technology Data Exchange (ETDEWEB)
Blumenthal, D.J.; Henning, W.; Janssens, R.V.F. [and others
1995-08-01
We performed an experiment to search for the two-phonon octupole vibrational state in {sup 208}Pb. Thick targets of {sup 208}Pb, {sup 209}Bi, {sup 58,64}Ni, and {sup 160}Gd were bombarded with 1305 MeV beams of were bombard {sup 208}Pb supplied by ATLAS. Gamma rays were detected using the Argonne-Notre Dame BGO gamma-ray facility, consisting of 12 Compton-suppressed germanium detectors surrounding an array of 50 BGO scintillators. We identified some 30 known gamma rays from {sup 208}Pb in the spectra gated by the 5{sup -} {yields} 3{sup -} and 3{sup -} {yields} 0{sup +} transitions in {sup 208}Pb. In addition, after unfolding these spectra for Compton response, we observed broad coincident structures in the energy region expected for the 2-phonon states. Furthermore, we confirmed the placement of a 2485 keV line observed previously in {sup 207}Pb and find no evidence consistent with the placement of this line in {sup 208}Pb. We are currently in the process of investigating the origin of the broadened lines observed in the spectra, extracting the excitation probability of states in {sup 208}Pb, and determining the relative probability of mutual excitation and neutron transfer in this reaction. An additional experiment is also being performed to collect much higher statistics germanium-germanium coincidence data for the thick {sup 208}Pb target.
Octupole correlations in excited 0{sup +} states of the actinides
Energy Technology Data Exchange (ETDEWEB)
Spieker, Mark; Endres, Janis; Zilges, Andreas [Institute for Nuclear Physics, University of Cologne (Germany); Bucurescu, Dorel; Pascu, Sorin; Zamfir, Nicolae-Victor [Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest (Romania); Faestermann, Thomas [Physik Department, Technische Universitaet Muenchen, Munich (Germany); Hertenberger, Ralf; Wirth, Hans-Friedrich [Fakultaet fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, Munich (Germany)
2014-07-01
New experimental data has once again shown the importance of the octupole degree of freedom in the actinides. To further study possible admixtures of double-octupole structures to the wave function of positive-parity states, a high-resolution (p,t) experiment on {sup 242}Pu has been recently performed at the Q3D magnetic spectrograph in Munich. Excited 0{sup +} states were populated in {sup 240}Pu up to an excitation energy of 3 MeV. The new data allowed for a stringent test of the predictions of the spdf interacting boson model. In order to find possible double-octupole 0{sup +} candidates in the actinides, the signature of close-lying first and second excited 0{sup +} states has been proposed. It is found that the observation of this signature coincides with an E1 γ-decay of the first excited 0{sup +} state, while this state is strongly populated in the (p,t) reaction.
Mixed-symmetry octupole and hexadecapole excitations in the N=52 isotones
Hennig, A; Werner, V; Ahn, T; Anagnostatou, V; Cooper, N; Derya, V; Elvers, M; Endres, J; Goddard, P; Heinz, A; Huges, R O; Ilie, G; Mineva, M N; Petkov, P; Pickstone, S G; Pietralla, N; Radeck, D; Ross, T J; Savran, D; Zilges, A
2015-01-01
Background: Excitations with mixed proton-neutron symmetry have been previously observed in the $N=52$ isotones. Besides the well established quadrupole mixed-symmetry states (MSS), octupole and hexadecapole MSS have been recently proposed for the nuclei $^{92}$Zr and $^{94}$Mo. Purpose: The heaviest stable $N=52$ isotone $^{96}$Ru was investigated to study the evolution of octupole and hexadecapole MSS with increasing proton number. Methods: Two inelastic proton-scattering experiments on $^{96}$Ru were performed to extract branching ratios, multipole mixing ratios, and level lifetimes. From the combined data, absolute transition strengths were calculated. Results: Strong $M1$ transitions between the lowest-lying $3^-$ and $4^+$ states were observed, providing evidence for a one-phonon mixed-symmetry character of the $3^{(-)}_2$ and $4^+_2$ states. Conclusions: $sdg$-IBM-2 calculations were performed for $^{96}$Ru. The results are in excellent agreement with the experimental data, pointing out a one-phonon he...
Shell evolution of stable N = 50-56 Zr and Mo nuclei with respect to low-lying octupole excitations
Energy Technology Data Exchange (ETDEWEB)
Gregor, E.T.; Scheck, M.; Chapman, R.; Gaffney, L.P.; Keatings, J.; Mashtakov, K.R.; O' Donnell, D.; Smith, J.F.; Spagnoletti, P.; Wiseman, C. [University of the West of Scotland, School of Engineering and Computing, Paisley (United Kingdom); SUPA, Scottish Universities Physics Alliance, Glasgow (United Kingdom); Thuerauf, M.; Werner, V. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany)
2017-03-15
For the N = 50-56 zirconium (Z = 40) and molybdenum (Z = 42) isotopes, the evolution of subshells is evaluated by extracting the effective single-particle energies from available particle-transfer data. The extracted systematic evolution of neutron subshells and the systematics of the excitation energy of the octupole phonons provide evidence for type-II shape coexistence in the Zr isotopes. Employing a simplistic approach, the relative effective single-particle energies are used to estimate whether the formation of low-lying octupole-isovector excitations is possible at the proposed energies. The results raise doubts about this assignment. (orig.)
Yao, J M
2016-01-01
We discuss anharmonicity of the multi-octupole-phonon states in $^{208}$Pb based on a covariant density functional theory, by fully taking into account the interplay between the quadrupole and the octupole degrees of freedom. Our results indicate the existence of a large anharmonicity in the transition strengths, even though the excitation energies are similar to those in the harmonic limit. We also show that the quadrupole-shape fluctuation significantly enhances the fragmentation of the two-octupole-phonon states in $^{208}$Pb. Using those transition strengths as inputs to coupled channels calculations, we then discuss the fusion reaction of $^{16}$O+$^{208}$Pb at energies around the Coulomb barrier. We show that the anharmonicity of the octupole vibrational excitation considerably improves previous coupled-channels calculations in the harmonic oscillator limit, significantly reducing the height of the main peak in the fusion barrier distribution.
Energy displacement function as a signature for octupole deformation in excited states
Raduta, A A; Ursu, I I
2003-01-01
Energies for three positive and three negative parity bands predicted by the extended coherent states model (ECSM) in sup 2 sup 2 sup 6 Ra are calculated and used to point out new signatures for octupole deformation in ground as well as in beta and gamma bands. A beat pattern is found by using a new displacement energy function which is more appropriate for a spectrum which exhibits large deviation from a linear J(J+1) dependence. The stability against octupole deformation is revisited from a new point of view. (authors)
Measurements of octupole collectivity in $^{220,222}$Rn and $^{222,224}$Ra using Coulomb excitation
Kruecken, R; Larsen, A; Hurst, A M; Voulot, D; Grahn, T; Clement, E; Wadsworth, R; Gernhaeuser, R A; Siem, S; Huyse, M L; Iwanicki, J S
2008-01-01
We propose to exploit the unique capability of ISOLDE to provide post-accelerated $^{220,222}$Rn and $^{222,224}$Ra ion beams from the REX facility to enable the Coulomb excitation of the first 3$^{-}$ states in these nuclei. By measuring the $\\gamma$-ray yields of the E1 decays from the 3$^{-}$ state using the MINIBALL array we can obtain the transition matrix elements. This will give quantitative information about octupole correlations in these nuclei. We require 22 shifts to fulfil the aims of the experiment.
Measurements of octupole collectivity in Rn and Ra nuclei using Coulomb excitation
We propose to exploit the unique capability of HIE-ISOLDE to provide post-accelerated $^{221,222}$Rn and $^{222,226,228}$Ra ion beams for the study of octupole collectivity in these nuclei. We will measure E3 transition moments in $^{222}$Rn and $^{222,226,228}$Ra in order to fully map out the variation in E3 strength in the octupole mass region with Z$\\thicksim$88 and N$\\thicksim$134. This will validate model calculations that predict different behaviour as a function of N. We will also locate the position of the parity doublet partner of the ground state in $^{221}$Rn, in order to test the suitability of odd-A radon isotopes for EDM searches.
Identification of excited states and evidence for octupole deformation in sup 2 sup 2 sup 6 U
Greenlees, P T
1999-01-01
Excited yrast states in the neutron-deficient nucleus sup 2 sup 2 sup 6 U have been identified in two experiments performed at the Accelerator Laboratory of the University of Jyvaeskylae, Finland. In the first, the technique of recoil-decay tagging was employed using the JUROSPHERE plus RITU device, where the reaction channel of interest is selected through correlation with a characteristic decay. In the second, the RITU device was employed to study the alpha decay of sup 2 sup 3 sup 0 Pu. Through these experiments the level scheme of sup 2 sup 2 sup 6 U was deduced for the first time. Interleaved bands of positive- and negative- parity states suggest the octupole nature of this nucleus, and the behaviour of the difference in aligned angular momentum between the negative- and positive- parity states with rotational frequency is consistent with that expected of a rotating reflection-asymmetric shape. This represents an extension of the known octupole-deformed nuclei to Z = 92. The interleaved bands of alternat...
We propose to exploit the unique capability of ISOLDE to provide intense post-accelerated $^{142}$Ba and $^{144}$Ba ion beams from the HIE-ISOLDE facility to enable the Coulomb excitation of the first 3$^-$ state in these nuclei. By measuring the $\\gamma$-ray yields of the E1 decays from the 3$^-$ state using the MINIBALL array, we can obtain the interesting transition matrix element. The results will give quantitative information about octupole correlations in these nuclei.
We propose to exploit the unique capability of ISOLDE to provide intense post-accelerated $^{144}$Ba ion beams from the REX facility to enable the Coulomb excitation of the first 3$^{-}$ state in this nucleus. By measuring the $\\gamma$-ray yields of the E1 decay connecting the 3$^{-}$ and 2$^{+}$ states using the MINIBALL array, we can obtain the interesting transition matrix element. The result will give quantitative information about octupole correlations in this nucleus. We require 27 shifts to fulfill the aims of the experiment.
Smirnova, N A; Mizusaki, T; Van Isacker, P
2000-01-01
The interrelation between the octupole phonon and the low-lying proton-neutron mixed-symmetry quadrupole phonon in near-spherical nuclei is investigated. The one-phonon states decay by collective E3 and E2 transitions to the ground state and by relatively strong E1 and M1 transitions to the isoscalar 2 sup + sub 1 state. We apply the proton-neutron version of the interacting boson model including quadrupole and octupole bosons ( sdf -IBM-2). Two F -spin symmetric dynamical symmetry limits of the model, namely the vibrational and the gamma -unstable ones, are considered. We derive analytical formulae for excitation energies as well as B(E1) , B(M1) , B(E2) and B(E3) values for a number of transitions between low-lying states.
Studies of Stable Octupole Deformations in the Radium Region
2002-01-01
The purpose of the present project is to locate and identify states in the atomic nuclei possessing stable pearshaped octupole deformation. Such states, formally related to the structures known in molecular physics, manifest themselves as families of parity doublets in odd nuclei.\\\\ \\\\ The best possibilities for observing stable octupole deformations are offered in the Ra-region. Both theoretical calculations and experimental indications support such expectations. Such indications are the non-observation of two-phonon octupole vibrational states in the ISOLDE studies of the even-even radium nuclei, and the reversed sign of the decoupling factor of the ground state band in |2|2|5Ra observed in the single-neutron transfer reactions. In order to establish the predicted strong E1 and E3-transitions between the parity doublets in odd nuclei with stable octupole deformations it is proposed to study conversion electrons in odd-mass francium radium and radon isotopes following the @b-decay of francium and astatine. \\...
The decay of quadrupole-octupole $1^-$ states in $^{40}$Ca and $^{140}$Ce
Derya, V; Aumann, T; Bhike, M; Endres, J; Gooden, M; Hennig, A; Isaak, J; Lenske, H; Löher, B; Pietralla, N; Savran, D; Tornow, W; Werner, V; Zilges, A
2016-01-01
Background: Two-phonon excitations originating from the coupling of two collective one-phonon states are of great interest in nuclear structure physics. One possibility to generate low-lying $E1$ excitations is the coupling of quadrupole and octupole phonons. Purpose: In this work, the $\\gamma$-decay behavior of candidates for the $(2_1^+\\otimes 3_1^-)_{1^-}$ state in the doubly-magic nucleus $^{40}$Ca and in the heavier and semi-magic nucleus $^{140}$Ce is investigated. Methods: $(\\vec{\\gamma},\\gamma')$ experiments have been carried out at the High Intensity $\\gamma$-ray Source (HI${\\gamma}$S) facility in combination with the high-efficiency $\\gamma$-ray spectroscopy setup $\\gamma^3$ consisting of HPGe and LaBr$_3$ detectors. The setup enables the acquisition of $\\gamma$-$\\gamma$ coincidence data and, hence, the detection of direct decay paths. Results: In addition to the known ground-state decays, for $^{40}$Ca the decay into the $3^-_1$ state was observed, while for $^{140}$Ce the direct decays into the $2...
Microscopic analysis of quadrupole-octupole shape evolution
Directory of Open Access Journals (Sweden)
Nomura Kosuke
2015-01-01
Full Text Available We analyze the quadrupole-octupole collective states based on the microscopic energy density functional framework. By mapping the deformation constrained self-consistent axially symmetric mean-field energy surfaces onto the equivalent Hamiltonian of the sdf interacting boson model (IBM, that is, onto the energy expectation value in the boson coherent state, the Hamiltonian parameters are determined. The resulting IBM Hamiltonian is used to calculate excitation spectra and transition rates for the positive- and negative-parity collective states in large sets of nuclei characteristic for octupole deformation and collectivity. Consistently with the empirical trend, the microscopic calculation based on the systematics of β2 – β3 energy maps, the resulting low-lying negative-parity bands and transition rates show evidence of a shape transition between stable octupole deformation and octupole vibrations characteristic for β3-soft potentials.
Octupole shapes in heavy nuclei
Energy Technology Data Exchange (ETDEWEB)
Ahmad, I.
1994-08-01
Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets.
Octupole Deformed Nuclei in the Actinide Region
Thorsteinsen, T; Rubio barroso, B; Simpson, J; Gulda, K; Sanchez-vega, M; Cocks, J; Nybo, K; Garcia borge, M; Aas, A; Fogelberg, B; Honsi, J; Smith, G; Naumann, R; Grant, I
2002-01-01
The aim of the present study is to investigate the limits of the "island" of octupole deformation in the mass region A=225. It is of particular importance to demonstrate experimentally the sudden disappearance of the stable octupole deformation in the presence of a well developed quadrupole field. \\\\ \\\\In order to establish the upper border line the $\\beta$ -decay chains of $^{227}$Rn $\\rightarrow ^{227}$Fr $\\rightarrow ^{227}$Ra and $^{231}$Fr $\\rightarrow ^{231}$Ra $\\rightarrow ^{231}$Ac were studied at PSB-ISOLDE using advanced fast timing and $\\gamma$-ray spectroscopy techniques. The lifetimes of the excited states have been measured in the picosecond range using the time-delayed $\\beta\\gamma\\gamma$(t) method.
Octupole response and stability of spherical shape in heavy nuclei
Energy Technology Data Exchange (ETDEWEB)
Abrosimov, V.I.; Davidovskaya, O.I.; Dellafiore, A. E-mail: della@fi.infn.it; Matera, F
2003-11-17
The isoscalar octupole response of a heavy spherical nucleus is analyzed in a semiclassical model based on the linearized Vlasov equation. The octupole strength function is evaluated with different degrees of approximation. The zero-order fixed-surface response displays a remarkable concentration of strength in the 1{Dirac_h}{omega} and 3{Dirac_h}{omega} regions, in excellent agreement with the quantum single-particle response. The collective fixed-surface response reproduces both the high- and low-energy octupole resonances, but not the low-lying 3{sup -} collective states, while the moving-surface response function gives a good qualitative description of all the main features of the octupole response in heavy nuclei. The role of triangular nucleon orbits, that have been related to a possible instability of the spherical shape with respect to octupole-type deformations, is discussed within this model. It is found that, rather than creating instability, the triangular trajectories are the only classical orbits contributing to the damping of low-energy octupole excitations.
On Landau damping of dipole modes by non-linear space charge and octupoles
Möhl, D
1995-01-01
The joint effect of space-charge non-linearities and octupole lenses is important for Landau damping of coherent instabilities. The octupole strength required for stabilisation can depend strongly on the sign of the excitation current of the lenses. This note tries to extend results, previously obtained for coasting beams and rigid bunches, to more general head--tail modes.
Octupole correlations in N =88 154Dy : Octupole vibration versus stable deformation
Zimba, G. L.; Sharpey-Schafer, J. F.; Jones, P.; Bvumbi, S. P.; Masiteng, L. P.; Majola, S. N. T.; Dinoko, T. S.; Lawrie, E. A.; Lawrie, J. J.; Negi, D.; Papka, P.; Roux, D.; Shirinda, O.; Easton, J. E.; Khumalo, N. A.
2016-11-01
We report on low-spin states of 154Dy populated via the reaction 155Gd (3He,4 n ) with a beam energy of 37.5 MeV from the Separated Sector Cyclotron at iThemba Laboratory. The AFRODITE γ-ray spectrometer was used to establish new E 1 transitions between bands of opposite parity. The measurements broaden the N =88 systematics on the relationship between the first excited positive-parity pairing isomer band and the lowest-lying negative-parity band as the nuclear quadrupole deformation decreases with increasing proton number. In a region of strong octupole correlations the data suggest that the spectroscopy of N =88 nuclei is driven by stable octupole deformations and not by vibrations.
Fragmentation of two-phonon {gamma}-vibrational strength in deformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Wu, C.Y.; Cline, D. [Univ. of Rochester, NY (United States)
1996-12-31
Rotational and vibrational modes of collective motion. are very useful in classifying the low-lying excited states in deformed nuclei. The rotational mode of collective motion is characterized by rotational bands having correlated level energies and strongly-enhanced E2 matrix elements. The lowest intrinsic excitation with I,K{sup {pi}} = 2,2{sup +} in even-even deformed nuclei, typically occurring at {approx}1 MeV, is classified as a one-phonon {gamma}-vibration state. In a pure harmonic vibration limit, the expected two-phonon {gamma}-vibration states with I,K{sup {pi}} = 0,0{sup +} and 4,4{sup +} should have excitation energies at twice that of the I,K{sup {pi}} = 2,2{sup +} excitation, i.e. {approx}2 MeV, which usually is above the pairing gap leading to possible mixing with two-quasiparticle configurations. Therefore, the question of the localization of two-phonon {gamma}-vibration strength has been raised because mixing may lead to fragmentation of the two-phonon strength over a range of excitation energy. For several well-deformed nuclei, an assignment of I,K{sup {pi}}=4,4{sup +} states as being two-phonon vibrational excitations has been suggested based on the excitation energies and the predominant {gamma}-ray decay to the I,K{sup {pi}}=2,2{sup +} state. However, absolute B(E2) values connecting the presumed two- and one-phonon states are the only unambiguous measure of double phonon excitation. Such B(E2) data are available for {sup 156}Gd, {sup 160}Dy, {sup 168}Er, {sup 232}Th, and {sup 186,188,190,192}Os. Except for {sup 160}Dy, the measured B(E2) values range from 2-3 Weisskopf units in {sup 156}Gd to 10-20 Weisskopf units in osmium nuclei; enhancement that is consistent with collective modes of motion.
Manipulation of Squeezed Two-Phonon Bound States using Femtosecond Laser Pulses
Directory of Open Access Journals (Sweden)
Nakamura Kazutaka G.
2013-03-01
Full Text Available Two-phonon bound states have been excited exclusively in ZnTe(110 via impulsive stimulated second-order Raman scattering, essentially being squeezed states due to phase coherent excitation of two identical components anticorrelated in the wave vector. By using coherent control technique with a pair of femtosecond laser pulses, the manipulation of squeezed states has been demonstrated in which both the amplitude and lifetime of coherent oscillations of squeezed states are modulated, indicating the feasibility to control the quantum noise and the quantum nature of phonon squeezed states, respectively.
Octupole strength in the neutron-rich calcium isotopes
Riley, L A; Agiorgousis, M L; Baugher, T R; Bazin, D; Bowry, M; Cottle, P D; DeVone, F G; Gade, A; Glowacki, M T; Gregory, S D; Haldeman, E B; Kemper, K W; Lunderberg, E; Noji, S; Recchia, F; Sadler, B V; Scott, M; Weisshaar, D; Zegers, R G T
2016-01-01
Low-lying excited states of the neutron-rich calcium isotopes $^{48-52}$Ca have been studied via $\\gamma$-ray spectroscopy following inverse-kinematics proton scattering on a liquid hydrogen target using the GRETINA $\\gamma$-ray tracking array. The energies and strengths of the octupole states in these isotopes are remarkably constant, indicating that these states are dominated by proton excitations.
The octupoles take pole position
2002-01-01
The first preseries octupole magnet was delivered to CERN in December 2001. Hooked up to a main quadrupole magnet, its function will be to correct imperfections in the beams. The LHC will be fitted with about 5000 corrector magnets, whose task it will be to provide maximum precision in beam collisions.
Agyare, Benjamin; Riseborough, Peter
2017-01-01
Intrinsically Localized Modes (ILMs) have purportedly been observed in NaI but only for wave-vectors, q at the corner of the 3-D Brillouin Zone. It has been suggested that, for high-symmetry q vectors, several van Hove singularities may converge at one frequency producing a large peak in the two-phonon density of state and giving rise to ILMs with these q values. We fit the experimentally determined acoustic and the optic phonon modes using a nearest neighbor and a next-nearest neighbor force constant. We find that the two-phonon density of states, for fixed q exhibits non-divergent van Hove singularities. The frequencies of these features are found to vary as q is varied. We intend to search for q values at which the two-phonon density of states is enhanced and then examine whether the anharmonic interactions can bind the two-phonon excitations to produce a quantized ILM.
Two-phonon 1- state in 112Sn observed in resonant photon scattering
Pysmenetska, I; Karg, O; Kneissl, U; Kohstall, C; Pitz, H H; Ponomarev, V Yu; Scheck, M; Stedile, F; Volz, S; Von Neumann-Cosel, P; Walter, S; Von Garrel, H
2006-01-01
Results of a photon scattering experiment on 112Sn using bremsstrahlung with an endpoint energy of E_0 = 3.8 MeV are reported. A J = 1 state at E_x = 3434(1) keV has been excited. Its decay width into the ground state amounts to Gamma_0 = 151(17) meV, making it a candidate for a [2+ x 3-]1- two-phonon state. The results for 112Sn are compared with quasiparticle-phonon model calculations as well as the systematics of the lowest-lying 1- states established in other even-mass tin isotopes. Contrary to findings in the heavier stable even-mass Sn isotopes, no 2+ states between 2 and 3.5 MeV excitation energy have been detected in the present experiment.
Octupole Vibrations Built on Superdeformed Rotational Bands
Mizutori, S.; Shimizu, Y. R.; Matsuyanagi, K.
1990-04-01
Strength functions for giant octupole resonances built on the superdeformed rotational bands are calculated by means of the RPA based on the cranking model. It is suggested that strongly collective octupole vibrational states appear within a few MeV from the superdeformed yrast line.
Octupole collectivity in the Sm isotopes
Energy Technology Data Exchange (ETDEWEB)
Babilon, M. [Yale Univ., New Haven, CT (United States). Wright Nuclear Structure Lab.]|[Technische Univ. Darmstadt (Germany). Inst. fuer Kernphysik; Zamfir, N.V. [Yale Univ., New Haven, CT (United States). Wright Nuclear Structure Lab.]|[National Inst. for Physics and Nuclear Engineering, Bucharest (Romania); Kusnezov, D. [Yale Univ., New Haven, CT (United States). Sloane Physics Lab.; McCutchan, E.A. [Yale Univ., New Haven, CT (United States). Wright Nuclear Structure Lab.; Zilges, A. [Technische Univ. Darmstadt (Germany). Inst. fuer Kernphysik
2005-08-27
Microscopic models suggest the occurrence of strong octupole correlations in nuclei with N{approx}88. To examine the signatures of octupole correlations in this region, the spdf Interacting Boson Approximation (IBA) Model is applied to the Sm isotopes with N = 86 - 92. The effects of including multiple negative parity bosons in the basis are compared to more standard one negative parity boson calculations and are analyzed in terms of signatures for strong octupole correlations. It is found that multiple negative parity bosons are needed to describe properties at medium spin. Bands with strong octupole correlations (multiple negative parity bosons) become yrast at medium spin in {sup 148,150}Sm. This region shares some similarities with the light actinides, where strong octupole correlations were also found at medium spin. (orig.)
Possible Octupole Correlation in 90Mo
Institute of Scientific and Technical Information of China (English)
LIGuang-sheng; WUXiao-guang; PENGZhao-hua; WENShu-xian; HANGuang-bing; LICheng-bo; LUShao-jun; WUShao-yong; YUANGuang-jun; YANGChun-xiang; ZHULi-hua
2003-01-01
The nuclei with octupole deformation have a feature of reflection asymmetry and so there exists a wealth of information about nuclear property. Therefore, study on behavior of high spin states for these nuclei is helpful to know nuclear structure further. Theories predict that octupole deformation with β3≠0 will occurs when the proton number Z and neutron number N are 56, 88, and 132.
Hong-Ou-Mandel interference of two phonons in trapped ions
Toyoda, Kenji; Hiji, Ryoto; Noguchi, Atsushi; Urabe, Shinji
2015-11-01
The quantum statistics of bosons and fermions manifest themselves in the manner in which two indistinguishable particles interfere quantum mechanically. When two photons, which are bosonic particles, enter a beam-splitter with one photon in each input port, they bunch together at either of the two output ports. The corresponding disappearance of the coincidence count is the Hong-Ou-Mandel effect. Here we show the phonon counterpart of this effect in a system of trapped-ion phonons, which are collective excitations derived by quantizing vibrational motions that obey Bose-Einstein statistics. We realize a beam-splitter transformation of the phonons by employing the mutual Coulomb repulsion between ions, and perform a two-phonon quantum interference experiment using that transformation. We observe an almost perfect disappearance of the phonon coincidence between two ion sites, confirming that phonons can be considered indistinguishable bosonic particles. The two-particle interference demonstrated here is purely a quantum effect, without a classical counterpart, hence it should be possible to demonstrate the existence of entanglement on this basis. We attempt to generate an entangled state of phonons at the centre of the Hong-Ou-Mandel dip in the coincidence temporal profile, under the assumption that the entangled phonon state is successfully generated if the fidelity of the analysis pulses is taken into account adequately. Two-phonon interference, as demonstrated here, proves the bosonic nature of phonons in a trapped-ion system. It opens the way to establishing phonon modes as carriers of quantum information in their own right, and could have implications for the quantum simulation of bosonic particles and analogue quantum computation via boson sampling.
Hong-Ou-Mandel interference of two phonons in trapped ions.
Toyoda, Kenji; Hiji, Ryoto; Noguchi, Atsushi; Urabe, Shinji
2015-11-05
The quantum statistics of bosons and fermions manifest themselves in the manner in which two indistinguishable particles interfere quantum mechanically. When two photons, which are bosonic particles, enter a beam-splitter with one photon in each input port, they bunch together at either of the two output ports. The corresponding disappearance of the coincidence count is the Hong-Ou-Mandel effect. Here we show the phonon counterpart of this effect in a system of trapped-ion phonons, which are collective excitations derived by quantizing vibrational motions that obey Bose-Einstein statistics. We realize a beam-splitter transformation of the phonons by employing the mutual Coulomb repulsion between ions, and perform a two-phonon quantum interference experiment using that transformation. We observe an almost perfect disappearance of the phonon coincidence between two ion sites, confirming that phonons can be considered indistinguishable bosonic particles. The two-particle interference demonstrated here is purely a quantum effect, without a classical counterpart, hence it should be possible to demonstrate the existence of entanglement on this basis. We attempt to generate an entangled state of phonons at the centre of the Hong-Ou-Mandel dip in the coincidence temporal profile, under the assumption that the entangled phonon state is successfully generated if the fidelity of the analysis pulses is taken into account adequately. Two-phonon interference, as demonstrated here, proves the bosonic nature of phonons in a trapped-ion system. It opens the way to establishing phonon modes as carriers of quantum information in their own right, and could have implications for the quantum simulation of bosonic particles and analogue quantum computation via boson sampling.
Electric Octupole Order in Bilayer Rashba System
Hitomi, Takanori; Yanase, Youichi
2016-12-01
The odd-parity multipole is an emergent degree of freedom, leading to spontaneous inversion symmetry breaking. The odd-parity multipole order may occur by forming staggered even-parity multipoles in a unit cell. We focus on a locally noncentrosymmetric bilayer Rashba system, and study an odd-parity electric octupole order caused by the antiferro stacking of local electric quadrupoles. Analyzing the forward scattering model, we show that the electric octupole order is stabilized by a layer-dependent Rashba spin-orbit coupling. The roles of the spin-orbit coupling are clarified on the basis of the analytic formula of multipole susceptibility. The spin texture allowed in the D2d point group symmetry and its magnetic response are revealed. Furthermore, we show that the parity-breaking quantum critical point appears in the magnetic field. The possible realization of the electric octupole order in bilayer high-Tc cuprate superconductors is discussed.
Direct Evidence of Octupole Deformation in Neutron-Rich $^{144}$Ba
Bucher, B; Wu, C Y; Janssens, R V F; Cline, D; Hayes, A B; Albers, M; Ayangeakaa, A D; Butler, P A; Campbell, C M; Carpenter, M P; Chiara, C J; Clark, J A; Crawford, H L; Cromaz, M; David, H M; Dickerson, C; Gregor, E T; Harker, J; Hoffman, C R; Kay, B P; Kondev, F G; Korichi, A; Lauritsen, T; Macchiavelli, A O; Pardo, R C; Richard, A; Riley, M A; Savard, G; Scheck, M; Seweryniak, D; Smith, M K; Vondrasek, R; Wiens, A
2016-01-01
The neutron-rich nucleus $^{144}$Ba ($t_{1/2}$=11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers $A$ less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced $E1$ transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multi-step Coulomb excitation of a post-accelerated 650-MeV $^{144}$Ba beam on a 1.0-mg/cm$^2$ $^{208}$Pb target. The measured value of the matrix element, $\\langle 3_1^- \\| \\mathcal{M}(E3) \\| 0_1^+ \\rangle=0.65(^{+17}_{-23})$ $e$b$^{3/2}$, corresponds to a reduced $B(E3)$ transition probability of 48($^{+25}_{-34}$) W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.
Spectroscopy of quadrupole and octupole states in rare-earth nuclei from a Gogny force
Nomura, K; Robledo, L M
2015-01-01
Collective quadrupole and octupole states are described in a series of Sm and Gd isotopes within the framework of the interacting boson model (IBM), whose Hamiltonian parameters are deduced from mean field calculations with the Gogny energy density functional. The link between both frameworks is the ($\\beta_2\\beta_3$) potential energy surface computed within the Hartree-Fock-Bogoliubov framework in the case of the Gogny force. The diagonalization of the IBM Hamiltonian provides excitation energies and transition strengths of an assorted set of states including both positive and negative parity states. The resultant spectroscopic properties are compared with the available experimental data and also with the results of the configuration mixing calculations with the Gogny force within the generator coordinate method (GCM). The structure of excited $0^{+}$ states and its connection with double octupole phonons is also addressed. The model is shown to describe the empirical trend of the low-energy quadrupole and o...
Evidence for octupole vibration in the superdeformed well of {sup 109}Hg
Energy Technology Data Exchange (ETDEWEB)
Crowell, B.; Janssens, R.V.F.; Carpenter, M.P.; Ahmad, I.; Harfenist, S.; Henry, R.G.; Khoo, T.L.; Lauritsen, T.; Nisius, D. [Argonne National Lab., IL (United States); Wilson, A.N. [Univ. of Liverpool (United Kingdom)] [and others
1994-07-01
An excited superdeformed (SD) band has been observed in {sup 19O}Hg which decays to the lowest-energy (yrast) SD band rather than to the less deformed states as observed in most known SD bands in the A{approximately}150 and A{approximately}190 regions. The band exhibits properties which are in good agreement with predictions of collective octupole vibrations in the SD well of {sup 19O}Hg.
Isovector multiphonon excitations in near spherical nuclei
Smirnova, N A; Pietralla, N; Van Isacker, P; Isacker, Piet Van; Mizusaki, Takahiro; Pietralla, Norbert; Smirnova, Nadya A.
2000-01-01
The lowest isoscalar and isovector quadrupole and octupole excitations in near spherical nuclei are studied within the the proton-neutron version of the interacting boson model including quadrupole and octupole bosons (sdf-IBM-2). The main decay modes of these states in near spherical nuclei are discussed.
Nadirbekov, M S; Strecker, M; Scheid, W
2016-01-01
In this work we examine the possibility to describe yrast positive- and negative-parity excitations of deformed even-even nuclei through a collective rotation model in which the nuclear surface is characterized by triaxial quadrupole and octupole deformations. The nuclear moments of inertia are expressed as sums of quadrupole and octupole parts. By assuming an adiabatic separation of rotation and vibration degrees of freedom we suppose that the structure of the positive- and negative- parity bands may be determined by the triaxial-rigid-rotor motion of the nucleus. By diagonalizing the Hamiltonian in a symmetrized rotor basis with embedded parity we obtain a model description for the yrast positive- and negative-parity bands in several actinide nuclei. We show that the energy displacement between the opposite-parity sequences can be explained as the result of the quadrupole-octupole triaxiality.
Octupole collectivity in $^{220}$Rn and $^{224}$Ra
Gaffney, Liam Paul
Collective properties of the radioactive nuclei $^{220}$Rn and $^{224}$Ra have been studied via Coulomb excitation of a 2.8$\\,$A.MeV radioactive ion beam (RIB) incident upon $^{60}$Ni, $^{112,114}$Cd and $^{120}$Sn targets. The experiments took place at the REX-ISOLDE RIB facility, CERN. De-excitation $\\gamma$-ray yields following multiple-step Coulomb excitation were detected in coincidence with recoiling target nuclei in the Miniball spectrometer. For the first time, B(E3;3$^+ \\rightarrow 0^+$) values have been directly measured with a radioactive ion beam. In the process, $^{224}$Ra becomes the heaviest post-accelerated RIB to date at ISOLDE (with the possible exception of the quasi-stable $^{238}$U). The measurements presented in this thesis represent a tripling of the number of nuclei around Z$\\simeq88$ and N$\\simeq134$, for which direct measurements of the octupole collectivity have been performed. The only previous measurements being for the relatively long-lived $^{226}$Ra. The $\\gamma$-ray yields, in...
Microscopic description of octupole shape-phase transitions in light actinides and rare-earth nuclei
Nomura, K; Niksic, T; Lu, Bing-Nan
2014-01-01
A systematic analysis of low-lying quadrupole and octupole collective states is presented, based on the microscopic energy density functional framework. By mapping the deformation constrained self-consistent axially symmetric mean-field energy surfaces onto the equivalent Hamiltonian of the $sdf$ interacting boson model (IBM), that is, onto the energy expectation value in the boson condensate state, the Hamiltonian parameters are determined. The study is based on the global relativistic energy density functional DD-PC1. The resulting IBM Hamiltonian is used to calculate excitation spectra and transition rates for the positive- and negative-parity collective states in four isotopic chains characteristic for two regions of octupole deformation and collectivity: Th, Ra, Sm and Ba. Consistent with the empirical trend, the microscopic calculation based on the systematics of $\\beta_{2}$-$\\beta_{3}$ energy maps, the resulting low-lying negative-parity bands and transition rates show evidence of a shape transition be...
Investigation of octupole vibrational states in 150Nd via inelastic proton scattering (p,p'g)
Elvers, M; Ahmed, T; Ahn, T; Anagnostatou, V; Cooper, N; Deng, C; Endres, J; Goddard, P; Heinz, A; Ilie, G; Jiang, E; Kueppersbusch, C; Radeck, D; Savran, D; Shenkov, N; Werner, V; Zilges, A
2011-01-01
Octupole vibrational states were studied in the nucleus $^{150}\\mathrm{Nd}$ via inelastic proton scattering with $\\unit[10.9]{MeV}$ protons which are an excellent probe to excite natural parity states. For the first time in $^{150}\\mathrm{Nd}$, both the scattered protons and the $\\gamma$ rays were detected in coincidence giving the possibility to measure branching ratios in detail. Using the coincidence technique, the $B(E1)$ ratios of the decaying transitions for 10 octupole vibrational states and other negative-parity states to the yrast band were determined and compared to the Alaga rule. The positive and negative-parity states revealed by this experiment are compared with Interacting Boson Approximation (IBA) calculations performed in the (spdf) boson space. The calculations are found to be in good agreement with the experimental data, both for positive and negative-parity states.
Two-phonon capture processes into quantum dots: The role of intermediate states
DEFF Research Database (Denmark)
Magnúsdóttir, Ingibjörg; Uskov, A. V.; Bischoff, Svend;
2003-01-01
We present a study of carrier capture into quantum dots via emission of longitudinal optical phonons. Two-phonon capture times are found to be of the order of some picoseconds at carrier densities 10^1^7cm^-^3 in situations where single-phonon capture processes are energetically prohibited. The i...
Octupole Vibrations Built on Superdeformed Rotational Bands : Progress Letters
Shoujirou, MIZUTORI; Yoshifumi R., SHIMIZU; Kenichi, Matsuyanagi; Department of Physics, Kyushu University; Department of Physics, Kyoto University
1990-01-01
Strength functions for giant octupole resonances built on the superdeformed rotational bands are calculated by means of the RPA based on the cranking model. It is suggested that strongly collective octupole vibrational states appear within a few MeV from the superdeformed yrast line.
Enders, J; Eberth, J; Fitzler, A; Fransen, C; Herzberg, R D; Kaiser, H; Käubler, L; Neuman-Cosel, P V; Pietralla, N; Ponomarev, V Yu; Richter, A; Schnare, H; Schwengner, R; Skoda, S; Thomas, H G; Tiesler, H; Weisshaar, D; Wiedenhöver, I
2000-01-01
Results of a sup 2 sup 0 sup 8 Pb (gamma,gamma') experiment are presented aiming at an identification of the 2 sup + member of the long-sought two-octupole phonon multiplet. Four E2 excitations have been observed below 6.5 MeV excitation energy, two of them for the first time. However, in contrast to new results of calculations within the quasiparticle-phonon nuclear model (QPM), no obvious candidate for the two-octupole phonon vibration could be found in the present study. We discuss the J suppi=2 sup + states detected in this as well as previous experiments with respect to their possible two-octupole phonon structure.
Two-phonon scattering in graphene in the quantum Hall regime
Alexeev, A. M.; Hartmann, R. R.; Portnoi, M. E.
2015-01-01
One of the most distinctive features of graphene is its huge inter-Landau-level splitting in experimentally attainable magnetic fields which results in the room-temperature quantum Hall effect. In this paper we calculate the longitudinal conductivity induced by two-phonon scattering in graphene in a quantizing magnetic field at elevated temperatures. It is concluded that the purely phonon-induced scattering, negligible for conventional semiconductor heterostructures under quantum Hall conditi...
Electron scattering from the octupole band in /sup 238/U
Energy Technology Data Exchange (ETDEWEB)
Hirsch, A.; Creswell, C.; Bertozzi, W.; Heisenberg, J.; Hynes, M.V.; Kowalski, S.; Miska, H.; Norum, B.; Rad, F.N.; Sargent, C.P.; Sasanuma, T.; Turchinetz, W.
1978-03-06
A simple model for nuclear surface vibrations in permanently deformed nuclei does well in reproducing electron scattering cross sections of rotational levels built on a K/sup ..pi../= 0/sup -/ intrinsic octupole vibration in /sup 238/U.
Design of Octupole Channel for Integrable Optics Test Accelerator
Energy Technology Data Exchange (ETDEWEB)
Antipov, Sergey [Chicago U.; Carlson, Kermit [Fermilab; Castellotti, Riccardo [Unlisted, IT; Valishev, Alexander [Fermilab; Wesseln, Steven [Fermilab
2016-06-01
We present the design of octupole channel for Integrable Optics Test Accelerator (IOTA). IOTA is a test accelerator at Fermilab, aimed to conduct research towards high-intensity machines. One of the goals of the project is to demonstrate high nonlinear betatron tune shifts while retaining large dynamic aperture in a realistic accelerator design. At the first stage the tune shift will be attained with a special channel of octupoles, which creates a variable octupole potential over a 1.8 m length. The channel consists of 18 identical air-cooled octupole magnets. The magnets feature a simple low-cost design, while meeting the requirements on maximum gradient - up to 1.4 kG/cm³, and field quality - strength of harmonics below 1%. Numerical simulations show that the channel is capable of producing a nonlinear tune shift of 0.08 without restriction of dynamic aperture of the ring.
Improvements on the present theoretical understanding of octupole correlations
Directory of Open Access Journals (Sweden)
Robledo L.M.
2014-03-01
Full Text Available Some intriguing results, obtained in a recent survey of octupole properties for all even-even nuclei, are reanalyzed in order to understand the origin of the strong disagreement with experimental data and/or the strange behaviours observed. The limitations of the rotational formula to describe E1 and E3 transition strengths are discussed as well as the role played by octupole-quadrupole coupling in some specific nuclei.
Consistent quadrupole-octupole collective model
Dobrowolski, A.; Mazurek, K.; Góźdź, A.
2016-11-01
Within this work we present a consistent approach to quadrupole-octupole collective vibrations coupled with the rotational motion. A realistic collective Hamiltonian with variable mass-parameter tensor and potential obtained through the macroscopic-microscopic Strutinsky-like method with particle-number-projected BCS (Bardeen-Cooper-Schrieffer) approach in full vibrational and rotational, nine-dimensional collective space is diagonalized in the basis of projected harmonic oscillator eigensolutions. This orthogonal basis of zero-, one-, two-, and three-phonon oscillator-like functions in vibrational part, coupled with the corresponding Wigner function is, in addition, symmetrized with respect to the so-called symmetrization group, appropriate to the collective space of the model. In the present model it is D4 group acting in the body-fixed frame. This symmetrization procedure is applied in order to provide the uniqueness of the Hamiltonian eigensolutions with respect to the laboratory coordinate system. The symmetrization is obtained using the projection onto the irreducible representation technique. The model generates the quadrupole ground-state spectrum as well as the lowest negative-parity spectrum in 156Gd nucleus. The interband and intraband B (E 1 ) and B (E 2 ) reduced transition probabilities are also calculated within those bands and compared with the recent experimental results for this nucleus. Such a collective approach is helpful in searching for the fingerprints of the possible high-rank symmetries (e.g., octahedral and tetrahedral) in nuclear collective bands.
Landau damping dynamic aperture and octupole in LHC
Gareyte, Jacques; Ruggiero, F
1997-01-01
Maximization of the dynamic aperture and Landau damping of the collective instabilities are partly conflicting requirements. On the one hand, the non-linearities of the lattice must be minimized at large oscillation amplitude to guarantee the stability of the single particle motion. On the other hand, a spread of the betatron frequencies is necessary to guarantee the stability of the collective motion of bunches of particles; this requires the introduction of non-linearities effective at small amplitudes. We show in this note that the `natural' spread of betatron tunes due to the field imperfections is inadequate or Landau damping. An octupole scheme is required to provide collective stability at high energy. At low energy it may be used to find the optimum between the correction of the octupolar field imperfections and Landau damping. The solution of the stability problem taking into account the two degrees of freedom of the transverse motion allows a significant saving in octupole strength: 144 octupoles wi...
Persistence of octupole correlations in sup 2 sup 3 sup 1 Ra
Fraile-Prieto, L M; Mach, H; Boutami, R; Aas, A J; Fogelberg, B; García-Raffi, L M; Grant, I S; Gulda, K; Hageboe, E; Kurcewicz, W; Kvasil, J; López, M J; Løvhøiden, G; Martínez, T; Rubio, B; Taín, J L; Tengblad, O
2001-01-01
The structure of sup 2 sup 3 sup 1 Ra, the heaviest odd Ra nucleus currently accessible for detailed spectroscopic investigation, has been studied in the beta sup - decay of sup 2 sup 3 sup 1 Fr. The main purpose has been to verify whether fast B(E1) rates and significant octupole correlations recently established in sup 2 sup 2 sup 9 Ra persist in sup 2 sup 3 sup 1 Ra. The excited states in sup 2 sup 3 sup 1 Ra have been determined for the first time. Spins and parities have been deduced from conversion electron measurements, while level half-lives in the ps and ns ranges have been measured with the Advanced Time Delayed beta gamma gamma(t) method. The moderately fast B(E1) rates found for transitions connecting the lowest-lying K suppi=5/2 sup+- and K suppi=1/2 sup+- bands, reveal the persistence of octupole collective effects in sup 2 sup 3 sup 1 Ra, although the B(E1) rates are lower than in sup 2 sup 2 sup 9 Ra. These findings reinforce the differences in the B(E1) systematics between isotonic Ra and Th ...
Study of octupole correlations in rare earth nuclei
Energy Technology Data Exchange (ETDEWEB)
Babilon, M.
2005-07-01
Possible signatures of octupole correlations are discussed in this thesis for the rare earth nuclei {sup 148-154}Sm and {sup 152}Gd. Microscopic models suggest the occurence of strong octupole correlations in nuclei with N {approx} 88. The available data on {sup 148-154}Sm isotopes allowed for the examination of signatures of octupole correlations through the study of systematics in this region within the framework of the spdf Interacting Boson Approximation (IBA) model. It was found that properties of low-lying states can be readily understood with a simple hamiltonian consisting of a known positive parity hamiltonian coupled to a negative parity boson, and that multiple negative parity bosons were needed to describe properties at higher spin. Experiments on {sup 152}Gd have been performed at wright nuclear structure laboratory of yale university to extend the investigations on octupole correlations to other N=88 nuclei. An experiment at the moving tape collector allowed for the determination of decay properties of low-spin levels in {sup 152}Gd. To obtain information on medium-spin states, including their branchings, a fusion evaporation experiment was performed at the SASSYER setup. Existing data were verified and knowledge of state properties was extended towards higher spins. (orig.)
Amusia, M Ya; Felfli, Z; Msezane, A Z
2007-01-01
The generalized oscillator strengths (GOS) of discrete excitations np-nd, both dipole (L=1) and octupole (L=3) are studied, the latter for the first time. We demonstrate that although the relevant transitions in the same atom are closely located in energy, the dependence of their GOS on the momentum transfer q squared, is remarkably different, so that the GOS corresponding to L=3 have at least one extra maximum as a function of q squared and dominate over those of the L=1, starting from about q=1.25$ atomic unit (a.u.). The calculations were performed in the one particle Hartree-Fock approximation and with account of many-electron correlations via the Random Phase Approximation with Exchange. The GOS are studied for values of q squared up to 30 a.u.
Octupole correlations in the odd-[ital Z] nuclei [sup 148-151]Eu
Energy Technology Data Exchange (ETDEWEB)
Jongman, J.R.; Bacelar, J.C.S.; Urban, W.; Noorman, R.F.; van Pol, J.; Steenbergen, T.; de Voigt, M.J.A. (Kernfysisch Versneller Instituut, 9747 AA Groningen (Netherlands)); Nyberg, J.; Sletten, G. (Neils Bohr Institute, Riso, 4000 Roskilde (Denmark)); Dionisio, J.; Vieu, C. (Centre de Spectrometrie Nucleaire et Spectrometrie de Masse, 91405 Orsay (France))
1994-12-01
The effects of octupole correlations in the [ital Z]=63 nuclei [sup 148[minus]151]Eu are studied. The persistency of octupole instability through the transitional region of near-spherical ([ital N][le]85) towards prolate nuclei ([ital N][ge]88) is established and discussed. Intrinsic dipole moments, which are experimentally inferred from the measured electric dipole transition rates observed between parity doublets, are used to characterize the strength of the octupole correlations.
Reflection Asymmetric Shell Model for the Description of Octupole Rotational Bands
Institute of Scientific and Technical Information of China (English)
GAO Zao-Chun; CHEN Yong-Shou
2001-01-01
The reflection asymmetric shell model has been formulated to describe the high spin states of octupole-deformed nuclei. The long-range separable forces of quadrupole, octupole and hexadecapole, as well as monopole and quadrupole pairing, are included in the Hamiltonian. The bases, on which the Hamiltonian is diagonalized, are the eigenstates of angular momentum and parity obtained by projecting the octupole-deformed multi-quasiparticle states onto good angular momentum and good parity. The general features of rotational octupole bands in eveneven nuclei can be reproduced by the model and the calculated result is in good agreement with experiment.
We propose to study excited states in isotopes north-east of the doubly-magic $^{132}$Sn by $\\gamma$-ray spectroscopy following "safe" Coulomb excitation. The experiment aims to the determine B(E2) and B(E3) values to follow the evolution of quadrupole and octupole collectivity when going away from the shell closures at Z = 50 and N = 82. The B(E2; 0$^+_{gs}$ $\\rightarrow$ 2$^+_{1}$) values in the even isotopes $^{138-144}$Xe have been measured at REX-ISOLDE and the systematic trend towards neutron-rich nuclei is well described even by an empirical Grodzins-type formula. An increasing dipole moment observed for $^{140,142}$Xe is interpreted as indirect signature of increasing octupole correlations peaking at N = 88. So far, no B(E3) values are known. In contrast to the Xe isotopes, the Te ones, in particular $^{136}$Te, are known for their notoriously irregular behaviour. In order to understand the nuclear structure also on a microscopic basis, the isotope $^{136}$Te with just one pair of protons and neutrons...
Energy Technology Data Exchange (ETDEWEB)
Smirnova, N.A.; Van Isacker, P. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France); Smirnova, N.A [Paris-11 Univ., 91 - Orsay (France). Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse]|[Institute for Nuclear Physics, Moscow State University (Russian Federation); Pietralla, N. [Institut fur Kernphysik, Universitat zu Koln (Germany)]|[Yale Univ., New Haven, CT (United States). Wright Nuclear Structure Lab; Mizusaki, T. [Tokyo Univ. (Japan). Dept. of Physics
2000-07-01
The interrelation between the octupole phonon and the low-lying proton-neutron mixed-symmetry quadrupole in near-spherical nuclei is investigated. The one-phonon states decay by collective E3 and E2 transitions to the ground state and by relatively strong E1 and M1 transitions to the isoscalar 2{sup +}{sub 1} state. We apply the proton-neutron version of the Interacting Boson Model including quadrupole and octupole bosons (sdf-IBM-2). Two F-spin symmetric dynamical symmetry limits of the model, namely the vibrational and the {gamma}-unstable ones, are considered. We derived analytical formulae for excitation energies as well as B(E1), B(M1), B(E2), and B(E3) values for a number of transitions between low-lying states. The model well reproduces many known transition strengths in the near spherical nuclei {sup 142}Ce and {sup 94}Mo. (authors)
Evidence for octupole vibration in the superdeformed well of {sup 190}Hg from eurogam
Energy Technology Data Exchange (ETDEWEB)
Crowell, B.; Carpenter, M.P.; Janssens, R.V.F. [and others
1995-08-01
Gammasphere experiments in 1993-94 brought to light the existence of an excited superdeformed (SD) band in {sup 190}Hg with the unusual property of decaying entirely to the lowest (yrast) SD band over 3-4 transitions, rather than to the normally deformed states as is usually the case in the A {approximately} 150 and A {approximately} 190 regions of superdeformation. Although M1 transitions between signature-partner SD bands were previously observed in {sup 193}Hg, no such mechanism was available to explain the situation in the even-even nucleus {sup 190}Hg, whose yrast SD band has no signature partner. The best explanation appears to lie in long-standing theoretical predictions that the SD minimum in the potential energy surface would be quite soft with respect to octupole vibrations. This would lead to enhanced E1 transitions connecting the one-phonon and zero-phonon states. The data and this interpretation were published. A shortcoming of the Gammasphere experiments was that they did not allow the definitive measurement of the energies of the gamma-ray transitions connecting the two bands, due to the very weak population of the excited band ({approximately}0.05% of the {sup 190}Hg channel) and also partly, we believed, to the angular distributions of the transitions, which were peaked near 90 degrees, where Gammasphere had few detectors.
Rotational character change of the one-phonon and two-phonon $\\gamma$ vibration in odd-$A$ nuclei
Matsuzaki, Masayuki
2014-01-01
\\item[Background] The $\\gamma$ vibration is the most typical low-lying collective motion prevailing the nuclear chart. But only few one-phonon rotational bands in odd-$A$ nuclei have been known. Furthermore, two-phonon states, even the band head, have been observed in a very limited number of nuclides not only of odd-$A$ but even-even. \\item[Purpose] Among them, that in $^{105}$Mo is unique in that Coriolis effects are expected to be stronger than in $^{103}$Nb and $^{105}$Nb on which theoretical studies were reported. Then the purpose of the present work is to study $^{105}$Mo paying attention to rotational character change of the one-phonon and two-phonon bands in comparison with the present author's previous studies on $^{103}$Nb and $^{105}$Nb. \\item[Method] The particle-vibration coupling model based on the cranking model and the random-phase approximation is used to calculate the vibrational states in rotating odd-$A$ nuclei. \\item[Results] The present model reproduces the observed yrast zero-phonon and...
Plasma resistivity measurements in the Wisconsin levitated octupole
Energy Technology Data Exchange (ETDEWEB)
Brouchous, D. A.
1980-11-01
Resistivity measurements parallel to the magnetic field were made on gun injected plasmas ranging in density from 10/sup 9/cm/sup -3/ to 10/sup 1/parallelcm/sup -3/ in the Wisconsin levitated octupole with toroidal and poloidal magnetic fields. The 10/sup 9/cm/sup -3/ plasma was collisionless with lambda/sub mfp/ > 100 mirror lengths, had T/sub e/ = 10 eV, T/sub i/ = 30 eV and was found to have anomalous resistivity scaling like eta = ..sqrt..T/sub e//n/sub e/ when E/sub parallel/ > E/su c/ is the Dreicer critical field. The 10/sup 12/cm/sup -3/ plasma was collisional with lambda/sub mfp/ < mirror length, had T/sub e/ = T/sub i/ approx. = .2 eV and was found to have Spitzer resistivity when E/sub parallel/ < E/sub c/.
Octupole-deformed molecular bands in {sup 21}Ne
Energy Technology Data Exchange (ETDEWEB)
Wheldon, C.; Thummerer, S.; Bohlen, H.G.; Gebauer, B.; Tumino, A. [Hahn-Meitner-Institut, SF7, Berlin (Germany); Kokalova, Tz.; Oertzen, W. von [Hahn Meitner Inst., Berlin (Germany). SF7; Freie Univ. Berlin (Germany). Fachbereich Physik; Massey, T.N. [Ohio University, Department of Physics and Astronomy, Athens, OH (United States); Angelis, G. de; Axiotis, M.; Gadea, A.; Kroell, Th.; Marginean, N.; Napoli, D.R.; De Poli, M.; Ur, C. [INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova) (Italy); Bazzacco, D.; Lenzi, S.M.; Rossi Alvarez, C.; Lunardi, S.; Menegazzo, R. [Dipartimento di Fisica dell' Universita and INFN, Sezione di Padova, Padova (Italy); Bizzeti, P.G.; Bizzeti-Sona, A.M. [Dipartimento di Fisica dell' Universita and INFN, Sesto Fiorentino (Firenze) (Italy)
2005-12-01
Cluster states up to 12 MeV in the stable light nucleus {sup 21}Ne, based on the {sup 16}O+n+{alpha} molecular configurations, have been populated in the incomplete-fusion reaction {sup 16}{sub 8}O({sup 7}{sub 3}Li,np){sup 21}{sub 10}Ne at 29.4 MeV. The observation of both intra- and inter-band transitions leads to a re-interpretation of some levels in the K{sup {pi}}=(3)/(2){sup -} and K{sup {pi}}=(1)/(2){sup -} bands. The implications of this re-ordering on the octupole doublet bands are examined. The data allow a more accurate determination of some previously uncertain level energies. The ''missing'' I{sup {pi}}=(5)/(2){sup -} level is also discussed. (orig.)
Suppression of quadrupole and octupole modes in red giants observed by Kepler
Stello, D; Fuller, J; Garcia, R A; Huber, D
2016-01-01
The asteroseismology of red giant stars has continued to yield surprises since the onset of high-precision photometry from space-based observations. An exciting new theoretical result shows that the previously observed suppression of dipole oscillation modes in red giants can be used to detect strong magnetic fields in the stellar cores. A fundamental facet of the theory is that nearly all the mode energy leaking into the core is trapped by the magnetic greenhouse effect. This results in clear predictions for how the mode visibility changes as a star evolves up the red giant branch, and how that depends on stellar mass, spherical degree, and mode lifetime. Here, we investigate the validity of these predictions with a focus on the visibility of different spherical degrees. We find that mode suppression weakens for higher degree modes with an average reduction in the quadrupole mode visibility of up to 49% for the least evolved stars in our sample, and no detectable suppression of octupole modes, in agreement w...
Frequency standard based on the octupole transition in {sup 171}Yb{sup +}
Energy Technology Data Exchange (ETDEWEB)
Huntemann, Nils; Okhapkin, Maxim; Lipphard, Burghard; Weyers, Stefan; Tamm, Christian; Peik, Ekkehard [Fachbereich Zeit und Frequenz, Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany)
2011-07-01
W present our results on the development of a new optical frequency standard based on the electric octupole (E3) transition {sup 2}S{sub 1/2}(F=0) {yields} {sup 2}F{sub 7/2}(F=3) of a single trapped laser-cooled {sup 171}Yb{sup +} ion at 467 nm. In comparison with a previously realized optical frequency standard in {sup 171}Yb{sup +} this E3 transition benefits from smaller systematic level shifts due to external fields and its negligible natural linewidth. Another important aspect of the new standard is its strong dependence on variations of the fine structure constant {alpha}. A recently built probe laser system and the use of a new efficient repump scheme allows to observe Fourier transform-limited linewidths below 7 Hz and a resonant excitation probability of more than 90 %. We lock the probe laser frequency to the resonance signal of the E3 transition and use a real-time extrapolation scheme to eliminate the huge light shift induced by the probe field. The unperturbed transition frequency was measured by a comparison to a caesium fountain clock using a frequency comb generator. The resulting uncertainty was mainly limited by the systematic uncertainty of the fountain clock.
Simulations of octupole compensation of head-tail instability at the Tevatron
Energy Technology Data Exchange (ETDEWEB)
Meiqin Xiao; Tanaji Sen; Frank Schmidts
2003-05-28
The proton lifetime in the Tevatron depends sensitively on chromaticities. Too low chromaticities can make the beam unstable due to the weak head-tail instability. One way to compensate this effect is to introduce octupoles to create a larger amplitude dependent betatron tune spread. However, the use of octupoles will also introduce additional side effects such as second order chromaticity, differential tune shifts and chromaticities on both proton and anti-proton helices. The non-linear effects may also reduce the dynamic aperture. There are 67 octupoles in 4 different circuits in the Tevatron which may be used for this purpose. We report on a simulation study to find the best combinations of polarities and strengths of the octupoles.
Properties of octupole-vibrational bands in the 160Dy nucleus
Usmanov, P. N.; Solnyshkin, A. A.; Vdovin, A. I.; Salikhbaev, U. S.
2014-11-01
The mixing of octupole-vibrational bands in the 160Dy nucleus is analyzed within a phenomenological model that involves Coriolis coupling. The energies of levels in the bands, the reduced probabilities for E1 transitions from the octupole-vibrational bands to the ground-state and γ bands, and the ratios of the reduced probabilities for these transitions to the neighboring levels of the ground-state band are calculated. Satisfactory agreement with available experimental data is reached.
Maclean, E H; Persson, T; Tomas, R; Wenninger, J
2013-01-01
During the 2012 LHC run several observations were made of shifts to tune, coupling and chromaticity which were correlated with changes in the powering of Landau octupoles. Understanding the chromaticity dependence is of particular importance given its influence on instabilities. This note briefly summarizes the observations and describes our understanding to-date of the relationship between Q, Q′, |C−| and the Landau octupole powering.
Influence of the octupole mode on nuclear high-K isomeric properties
Minkov, Nikolay; Walker, Phil
2014-05-01
The influence of quadrupole-octupole deformations on the energy and magnetic properties of high-K isomeric states in even-even actinide (U, Pu, Cm, Fm, No), rare-earth (Nd, Sm and Gd), and superheavy (^{270}\\text{Ds}) nuclei is examined within a deformed shell model with pairing interaction. The neutron two-quasiparticle (2qp) isomeric energies and magnetic dipole moments are calculated over a wide range in the plane of quadrupole and octupole deformations. In most cases the magnetic moments exhibit a pronounced sensitivity to the octupole deformation. At the same time, the calculations outline three different groups of nuclei: with pronounced, shallow, and missing minima in the 2qp energy surfaces with respect to the octupole deformation. The result indicates regions of nuclei with octupole softness as well as with possible octupole deformation in the high-K isomeric states. These findings show the need for further theoretical analysis as well as of detailed experimental measurements of magnetic moments in heavy deformed nuclei.
Long-term Phanerozoic octupole fields and consequences for paleogeographic reconstructions
van der Voo, R.; Torsvik, T.
2003-04-01
The assumption that the ancient geomagnetic field was purely dipolar is fundamental to paleomagnetism. However, one sign that something may be amiss is that observed inclinations at mid-latitudes are often lower than expected. A zonal octupole field in the late Paleozoic, Mesozoic and Early Tertiary was revealed by comparing the observed paleomagnetic paleolatitude distributions for Laurussia (North America, Greenland, and Europe) with those predicted from the mean paleopoles. When only volcanics are analyzed, the pattern remains unchanged, indicating that inclination error in sediments is not the culprit. Estimates of the magnitude of the octupole/dipole field ratio center around 0.1, which could cause errors in conventional paleopoles of about 7.5 degrees; because of the antisymmetry of octupole fields a comparison of paleomagnetic poles from mid-northern and mid-southern hemisphere locations could thus be off by as much as 15 degrees. The well-known misfit between the paleomagnetic results from the Laurentia-European and Gondwana continents in a classical Pangea A configuration could be explained by such errors due to octupole fields. This explanation would negate the need to seek tectonic (Pangea B type) solutions for the misfit. Another misfit based on too-low inclinations is seen in a comparison of Central Asian poles with those for the Eurasian reference path, and here as well do octupole fields provide a possible solution, although sedimentary inclination shallowing is another possibility. When including Pre-Permian poles for Gondwana in a similar test for non-dipole fields, an increase in the percentage octupole contribution is suggested for older times. Undoubtedly, the octupole field contributions have varied in magnitude over shorter time scales as well.
Octupole Focusing Relativistic Self-Magnetometer Electric Storage Ring "Bottle"
Talman, Richard
2015-01-01
A method proposed for measuring the electric dipole moment (EDM) of a charged fundamental particle such as the proton, is to measure the spin precession caused by a radial electric bend field $E_r$, acting on the EDMs of frozen spin polarized protons circulating in an all-electric storage ring. The dominant systematic error limiting such a measurement comes from spurious spin precession caused by unintentional and unknown average radial magnetic field $B_r$ acting on the (vastly larger) magnetic dipole moments (MDM) of the protons. Along with taking extreme magnetic shielding measures, the best protection against this systematic error is to use the storage ring itself, as a "self-magnetometer"; the exact magnetic field average $\\langle B_r\\rangle$ that produces systematic EDM error, is nulled to exquisite precision by orbit position control. By using octupole rather than quadrupole focusing the restoring force can be vanishingly small for small amplitude vertical betatron-like motion yet strong enough at larg...
Shcherbakov, A S; Arellanes, A O; Chavushyan, V
2016-12-01
We develop an advanced approach to the optical spectrometer with acousto-optical dynamic grating for the Guillermo Haro astrophysical observatory (Mexico). The progress consists of two principle novelties. First is the use of the acousto-optical nonlinearity of two-phonon light scattering in crystals with linear acoustic losses. This advanced regime of light scattering exhibits a recently revealed additional degree of freedom, which allows tuning of the frequency of elastic waves and admits the nonlinear apodization improving the dynamic range. The second novelty is the combination of the cross-disperser with acousto-optical processing. A similar pioneering step provides an opportunity to operate over all the visible range in a parallel regime with maximal achievable resolution. The observation window of the optical spectrometer in that observatory is ∼9 cm, so that the theoretical estimations of maximal performances for a low-loss LiNbO3 crystal for this optical aperture at λ=405 nm give spectral resolution of 0.0523 Å, resolving power of 77,400, and 57,500 spots. The illustrative proof-of-principle experiments with a 6 cm LiNbO3 crystal have been performed.
Stable and Vibrational Octupole Modes in Mo, Xe, Ba, La, Ce and Nd
Energy Technology Data Exchange (ETDEWEB)
Gore, P.M.; Hamilton, J.H.; Hwang, J.K.; Jones, E.F.; Peker, L.K.; Ramayya, A.V.; Zhang, X.Q.; Zhu, S.J.
1998-05-18
Evidence is presented for stable octupole deformation in neutron-rich nuclei, bounded by Z = 54-58 and N = 85-92. To either side of this region negative parity bands built on more vibrational type octupole modes are observed in {sup 140}Ba and {sup 152,154}Nd. The largest stable octupole deformation ({beta}{sub s} {approximately} 0.1) is found in {sup 144}Ba{sub as}. The theoretically predicted quenching ({beta}{sub s} {approximately} 0) of stable octupole deformation at higher spins is found in {sup 140}Ba. There is good agreement between theory and experiment for the strongly varying electric dipole moments as a function of mass for {sup 142-141}Ba. In odd-A {sup 142}Ba and odd-Z {sup 140}La, we observe parity doublets, two pairs of positive and negative parity bands with opposite spins. In {sup 145}La a strong coupled ground band with symmetric shape coexists with the asymmetric octupole shape which stabilizes above about spin 19/2. In {sup 145,147}La a strong reduction in E2 strength around 25/2 from band crossing is observed. The isotope {sup 109}Mo was identified and a new region of stable uctpole deformation is identified in {sup 107,108}Mo centered around N = 64-66 as earlier predicted. This is the first case of stable uctpole deformation involving only one pair of orbitals.
Specifications of the octupole magnets required for the ATF2 ultra-low ß* lattice
Energy Technology Data Exchange (ETDEWEB)
Marin, E.; /SLAC; Modena, M.; /CERN; Tauchi, T.; Terunuma, N.; /KEK, Tsukuba; Tomas, R.; /CERN; White, G.R.; /SLAC
2014-05-28
The Accelerator Test Facility 2 (ATF2) aims to test the novel chromaticity correction for higher chromaticity lattices as the one of CLIC. To this end the ATF2 ultra-low ß* lattice is designed to vertically focus the beam at the focal point or usually referred to as interaction point (IP), down to 23 nm. However when the measured multipole components of the ATF2 magnets are considered in the simulations, the evaluated spot sizes at the IP are well above the design value. The designed spot size is effectively recovered by inserting a pair of octupole magnets. In this note we address the technical specifications required for these octupole magnets.
Energy Technology Data Exchange (ETDEWEB)
Trabert, E; Beiersdorfer, P; Brown, G V; Boyce, K; Kelley, R L; Kilbourne, C A; Porter, F S; Szymkowiak, A
2005-11-11
A microcalorimeter with event mode capability for time-resolved soft-x-ray spectroscopy, and a high-resolution flat-field EUV spectrometer have been employed at the Livermore EBIT-I electron beam ion trap for observations and wavelength measurements of M1, E2, and M3 decays of long-lived levels in the Ni-like ions Xe{sup 26+}, Cs{sup 27+}, and Ba{sup 28+}. Of particular interest is the lowest excited level, 3d{sup 9}4s {sup 3}D{sub 3}, which can only decay via a magnetic octupole (M3) transition. For this level in Xe an excitation energy of (590.40 {+-} 0.03eV) and a level lifetime of (11.5 {+-} 0.5 ms) have been determined.
Influence of angular momentum in axially symmetric potentials with octupole deformation
Institute of Scientific and Technical Information of China (English)
JIN Hua; SUN Zhen-Wu; ZHENG Ren-Rong
2009-01-01
The chaotic classical single-particle motion in an oblate octupole deformed potential with a non-zero z-component of angular momentum Lz is investigated. The stability analysis of the trajectories shows that with increasing rotation of the system, the unstable negative curvature regions of the effective potential surface decrease, which converts the chaotic motion of the system into a regular one.
Convective cells and their relationship to vortex diffusion in the Wisconsin Levitated Octupole
Energy Technology Data Exchange (ETDEWEB)
Ehrhardt, A.B.
1978-01-01
The purpose of this thesis is two-fold: first, to present floating potential structure for different plasmas and operating parameters in the Wisconsin Levitated Octupole. Second, to show how the observed potential structure can be used, within the framework of vortex diffusion, to account for enhanced diffusion in the appropriate parameter regimes.
Energy Technology Data Exchange (ETDEWEB)
Mizutori, Shoujirou; Matsuyanagi, Kenichi (Kyoto Univ. (Japan). Dept. of Physics); Shimizu, Y.R.
1991-07-01
Properties of low-lying octupole vibrations (with K=0, 1, 2 and 3) built on superdeformed rotational bands are investigated by means of the RPA in a uniformly rotating frame. Large configuration space composed of 9 major shells is used. Numerical examples are presented for the superdeformed band in {sup 192}Hg as a typical case where appreciable amount of static pairing correlations remains at finite values of the rotational frequency. We obtain strongly collective low-frequency octupole vibrations with K=0, 1 and 2. It is shown that the properties of the K=1 octupole vibrations are especially sensitive to the static pairing correlations. The Coriolis-mixings among these soft octupole vibrations are shown to become important when the rotational frequency {omega}{sub rot} > or approx. 0.2 MeV/{Dirac h}. (author).
Mizutori, S.; Shimizu, Y. R.; Matsuyanagi, K.
1991-07-01
Properties of low-lying octupole vibrations (with K = 0, 1, 2 and 3) built on superdeformed rotational bands are investigated by means of the RPA in a uniformly rotating frame. Large configuration space composed of 9 major shells is used. Numerical examples are presented for the superdeformed band in (192) Hg as a typical case where appreciable amount of static pairing correlations remains at finite values of the rotational frequency. We obtain strongly collective low-frequency octupole vibrations with K = 0, 1 and 2. It is shown that the properties of the K = 1 octupole vibrations are especially sensitive to the static pairing correlations. The Coriolis-mixings among these soft octupole vibrations are shown to become important when the rotational frequency omega_{mathrm{rot}} gtrsim 0.2 MeV/hbar.
Dzuba, V A
2016-01-01
Hyperfine-induced electric dipole contributions may significantly increase probabilities of otherwise very weak electric octupole and magnetic quadrupole atomic clock transitions (e.g. transitions between $s$ and $f$ electron orbitals). These transitions can be used for exceptionally accurate atomic clocks, quantum information processing and search for dark matter. They are very sensitive to new physics beyond the Standard Model, such as temporal variation of the fine structure constant, the Lorentz invariance and Einstein equivalence principle violation. We formulate conditions under which the hyperfine-induced electric dipole contribution dominates. Due to the hyperfine quenching the electric octupole clock transition in $^{173}$Yb$^+$ is two orders of magnitude stronger than that in currently used $^{171}$Yb$^+$. Some enhancement is found in $^{143}$Nd$^{13+}$, $^{149}$Pm$^{14+}$, $^{147}$Sm$^{14+}$, and $^{147}$Sm$^{15+}$ ions.
Lower hybrid heating associated with mode conversion on the Wisconsin octupole
Energy Technology Data Exchange (ETDEWEB)
Owens, T.L.
1979-08-01
This thesis addresses the following key issues in the lower hybrid frequency range: 1. What are the importent physics aspects of wave propagation and heating in an experimental situation. 2. How effective is plasma heating in the complex magnetic field configuration of the octupole. Experimental work is accomplished by launching 1-10ms pulses of up to 40kW of radio frequency power at 140MHz corresponding to the hot plasma lower hybrid resonance in the octupole. A diploe antenna which is moveable radially and is also rotatable couples wave power to the plasma. Coupling efficiencies greater than 95% are achieved by proper antenna placement near the edge of the plasma radial density profile.
Symmetry enriched U(1) topological orders for dipole-octupole doublets on a pyrochlore lattice
Li, Yao-Dong; Chen, Gang
2017-01-01
Symmetry plays a fundamental role in our understanding of both conventional symmetry breaking phases and the more exotic quantum and topological phases of matter. We explore the experimental signatures of symmetry enriched U(1) quantum spin liquids (QSLs) on the pyrochlore lattice. We point out that the Ce local moment of the newly discovered pyrochlore QSL candidate Ce2Sn2O7 , is a dipole-octupole doublet. The generic model for these unusual doublets supports two distinct symmetry enriched U(1) QSL ground states in the corresponding quantum spin ice regimes. These two U(1) QSLs are dubbed dipolar U(1) QSL and octupolar U(1) QSL. While the dipolar U(1) QSL has been discussed in many contexts, the octupolar U(1) QSL is rather unique. Based on the symmetry properties of the dipole-octupole doublets, we predict the peculiar physical properties of the octupolar U(1) QSL, elucidating the unique spectroscopic properties in the external magnetic fields. We further predict the Anderson-Higgs transition from the octupolar U(1) QSL driven by the external magnetic fields. We identify the experimental relevance with the candidate material Ce2Sn2O7 and other dipole-octupole doublet systems.
Yao, J M
2016-01-01
We present a generator-coordinate calculation, based on a relativistic energy-density functional, of the low-lying spectra in the isotopes $^{150}$Nd and $^{150}$Sm and of the nuclear matrix element that governs the neutrinoless double-beta decay of the first isotope to the second. We carefully examine the impact of octupole correlations on both nuclear structure and the double-beta decay matrix element. Octupole correlations turn out to reduce quadrupole collectivity in both nuclei. Shape fluctuations, however, dilute the effects of octupole deformation on the double-beta decay matrix element, so that the overall octupole-induced quenching is only about 7\\%.
Institute of Scientific and Technical Information of China (English)
Luo Zhi-Hua; Cao Xi-Jin; Yu Chao-Fan
2011-01-01
Based on the Holstein model Hamiltonian of one-dimensional molecular crystals, by making use of the expansion approach of the correlated squeezed-coherent states of phonon instead of the two-phonon coherent state expansion scheme, the properties of the ground state and the anomalous quantum fluctuations are investigated in a strongly coupled electron-phonon system with special consideration of the electron-two-phonon interaction. The effective renormalization ((～α)i) of the displacement of the squeezed phonons with the effect of the squeezed-coherent states of phonon and both the electron-displaced phonon and the polaron-squeezed phonon correlations have been combined to obtain the anomalous quantum fluctuations for the corrections of the coherent state. Due to these non-adiabatic correlations, the effective displacement parameter (～α)i is larger than the ordinary parameter αi(0). In comparison with the electron-one-phonon interaction (g) corrected as (～α)ig, we have found the electron-two-phonon interaction (g1) corrected as (～α)2ig1 is enhanced significantly. For this reason, the ground state energy (EO(2)) contributed by the electron-two-phonon interaction is more negative than the single-phonon case (EO(1)) and the soliton solution is more stable. At the same time, the effects of the electron-two-phonon interaction greatly increase the polaron energy and the quantum fluctuations. Furthermore,in a deeper level, we have considered the effect of the polaron-squeezed phonon correlation (f-correlation). Since this correlation parameter f ＞ 1, this effect will strengthen the electron-one and two-phonon interactions by f(～α)ig and f2( ～α)2i1, respectively. The final results show that the ground state energy and the polaron energy will appear more negative further and the quantum fluctuations will gain further improvement.
A novel antiproton radial diagnostic based on octupole induced ballistic loss
Andresen, G. B.; Bertsche, W.; Bowe, P. D.; Bray, C. C.; Butler, E.; Cesar, C. L.; Chapman, S.; Charlton, M.; Fajans, J.; Fujiwara, M. C.; Funakoshi, R.; Gill, D. R.; Hangst, J. S.; Hardy, W. N.; Hayano, R. S.; Hayden, M. E.; Humphries, A. J.; Hydomako, R.; Jenkins, M. J.; Jørgensen, L. V.; Kurchaninov, L.; Lambo, R.; Madsen, N.; Nolan, P.; Olchanski, K.; Olin, A.; Page, R. D.; Povilus, A.; Pusa, P.; Robicheaux, F.; Sarid, E.; El Nasr, S. Seif; Silveira, D. M.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Wurtele, J. S.; Yamazaki, Y.
2008-03-01
We report results from a novel diagnostic that probes the outer radial profile of trapped antiproton clouds. The diagnostic allows us to determine the profile by monitoring the time history of antiproton losses that occur as an octupole field in the antiproton confinement region is increased. We show several examples of how this diagnostic helps us to understand the radial dynamics of antiprotons in normal and nested Penning-Malmberg traps. Better understanding of these dynamics may aid current attempts to trap antihydrogen atoms.
Betatron Tune Spread Generation and Differential Chromaticity Control by Octupole at Tevatron
Ivanov, Petr M; Annala, Jerry; Lebedev, Valeri
2005-01-01
Application of octupoles for Landau damping of the unstable head-tail modes requires careful consideration at their combination into separate families to insure maximum effectiveness and avoid degradation of the dynamic aperture due to the non-linear magnetic fields. Existing octupolar magnets around the machine have been arranged into four functional families with individual power supplies. Two of these families generate betatron tune spreads in the vertical and horizontal planes whereas the other two control the differential chromaticity between the proton and antiproton helices. The calculated effect on tunes and chromaticity is compared with direct measurements. Analytical formulas for betatron tune spectral density functions are presented.
A novel antiproton radial diagnostic based on octupole induced ballistic loss
Andresen, G B; Bowe, P D; Bray, C C; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A J; Hydomako, R; Jenkins, M J; Jørgensen, L V; Kurchaninov, L; Lambo, R; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Page, R D; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Seif El Nasr, S; Silveira, D M; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y
2008-01-01
We report results from a novel diagnostic that probes the outer radial profile of trapped antiproton clouds. The diagnostic allows us to determine the profile by monitoring the time-history of antiproton losses that occur as an octupole field in the antiproton confinement region is increased. We show several examples of how this diagnostic helps us to understand the radial dynamics of antiprotons in normal and nested Penning-Malmberg traps. Better understanding of these dynamics may aid current attempts to trap antihydrogen atoms.
Calvo, Florent; Yurtsever, Ersin
2009-01-01
The stable structures and melting properties of ion clouds in isotropic octupole traps are investigated using a combination of semi-analytical and numerical models, with a particular emphasis at finite size scaling effects. Small-size clouds are found to be hollow and arranged in shells corresponding approximately to the solutions of the Thomson problem. The shell structure is lost in clusters containing more than a few thousands of ions, the inner parts of the cloud becoming soft and amorphous. While melting is triggered in the core shells, the melting temperature unexpectedly follows the rule expected for three-dimensional dense particles, with a depression scaling linearly with the inverse radius.
Structure of Hamiltonian Matrix and the Shape of Eigenfunctions: Nuclear Octupole Deformation Model
Institute of Scientific and Technical Information of China (English)
XING Yong-Zhong; LI Jun-Qing; LIU Fang; ZUO Wei
2002-01-01
The structure of a Hamiltonian matrix for a quantum chaotic system, the nuclear octupole deformationmodel, has been discussed in detail. The distribution of the eigenfunctions of this system expanded by the eigenstates ofa quantum integrable system is studied with the help ofgeneralized Brillouin-Wigner pcrturbation theory. The resultsshow that a significant randomness in this distribution can be observed when its classical counterpart is under the strongchaotic condition. The averaged shape of the eigenfunctions fits with the Gaussian distribution only when the effects ofthe symmetry have been removed.
Exotic octupole deformation in proton-rich Z=N nuclei
Energy Technology Data Exchange (ETDEWEB)
Takami, Satoshi; Yabana, K. [Niigata Univ. (Japan); Matsuo, M.
1998-03-01
We study static non-axial octupole deformations in proton-rich Z=N nuclei, {sup 64}Ge, {sup 68}Se, {sup 72}Kr, {sup 76}Sr, {sup 80}Zr and {sup 84}Mo, by using the Skyrme Hartree-Fock plus BCS method with no restrictions on the nuclear shape. The calculation predicts that the oblate ground state in {sup 68}Se is extremely soft for the Y{sub 33} triangular deformation, and that in {sup 80}Zr the low-lying local minimum state coexisting with the prolate ground state has the Y{sub 32} tetrahedral deformation. (author)
High-accuracy optical clock based on the octupole transition in 171Yb+
Huntemann, N; Lipphardt, B; Weyers, S; Tamm, Chr; Peik, E
2011-01-01
We experimentally investigate an optical frequency standard based on the 467 nm (642 THz) electric-octupole reference transition 2S1/2(F=0) -> F7/2(F=3) in a single trapped 171Yb+ ion. The extraordinary features of this transition result from the long natural lifetime and from the 4f136s2 configuration of the upper state. The electric quadrupole moment of the 2F7/2 state is measured as -0.041(5) e(a0)^2, where e is the elementary charge and a0 the Bohr radius. We also obtain information on the differential scalar and tensorial components of the static polarizability and of the probe light induced ac Stark shift of the octupole transition. With a real-time extrapolation scheme that eliminates this shift, the unperturbed transition frequency is realized with a fractional uncertainty of 7.1x10^(-17). The frequency is measured as 642 121 496 772 645.15(52) Hz with the uncertainty essentially determined by the employed caesium fountain reference.
High-accuracy optical clock based on the octupole transition in 171Yb+.
Huntemann, N; Okhapkin, M; Lipphardt, B; Weyers, S; Tamm, Chr; Peik, E
2012-03-02
We experimentally investigate an optical frequency standard based on the 467 nm (642 THz) electric-octupole reference transition (2)S(1/2)(F=0)→(2)F(7/2)(F=3) in a single trapped (171)Yb(+) ion. The extraordinary features of this transition result from the long natural lifetime and from the 4f(13)6s(2) configuration of the upper state. The electric-quadrupole moment of the (2)F(7/2) state is measured as -0.041(5)ea(0)(2), where e is the elementary charge and a(0) the Bohr radius. We also obtain information on the differential scalar and tensorial components of the static polarizability and of the probe-light-induced ac Stark shift of the octupole transition. With a real-time extrapolation scheme that eliminates this shift, the unperturbed transition frequency is realized with a fractional uncertainty of 7.1×10(-17). The frequency is measured as 642 121 496 772 645.15(52) Hz.
Studies of electric dipole moments in the octupole collective regions of heavy Radiums and Bariums
Hoff, P; Kaczarowski, R
2002-01-01
%IS386 %title\\ \\It is proposed to study the electric dipole moments in the regions of octupole collective Ra-Th and Ba-Ce nuclei by means of Advanced Time-Delayed (ATD) $\\beta\\gamma\\gamma(t)$ method with a primary goal to provide new and critical data on the properties of E1 moments. The proposal focuses on the nuclei of $^{225,226,229}$Ra, $^{229,233}$Th and $^{149,150}$Ba.\\ \\The ATD $\\beta\\gamma\\gamma$(t) method was first tested at ISOLDE as part of the IS322 study of Fr-Ra nuclei at the limits of octupole deformation region. The results have greatly increased the knowledge of electric dipole moments in the region and demonstrated that new and unique research capabilities in this field are now available at ISOLDE. Based on the experience and new systematics, we propose a specialized study with the aim to determine the missing key aspects of the E1 moment systematics. We propose : \\begin{enumerate}[a)] \\item to measure the lifetimes of the 1$_{1}^{-}$ and 3$_{1}^{-}$ states in $^{226}$Ra with $\\sim$15\\% prec...
Low-spin excitations in {sup 146}Sm
Energy Technology Data Exchange (ETDEWEB)
Kueppersbusch, C.; Brentano, P. von; Endres, J.; Elvers, M.; Friessner, C.; Zell, K.O.; Zilges, A. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany); Pascu, S. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany); National Institute for Physics and Nuclear Engineering, Bucharest-Magurele (Romania); Bucurescu, D.; Deleanu, D.; Filipescu, D.; Ghita, D.G.; Glodariu, T.; Mihai, C.; Marginean, N.M.; Marginean, R.; Negret, A.; Sava, T.; Stroe, L.; Zamfir, N.V. [National Institute for Physics and Nuclear Engineering, Bucharest-Magurele (Romania); Cata-Danil, G. [National Institute for Physics and Nuclear Engineering, Bucharest-Magurele (Romania); University POLITEHNICA of Bucharest, Physics Department, Bucharest (Romania); Werner, V. [Yale University, Wright Nuclear Structure Laboratory, New Haven, Connecticut (United States)
2012-01-15
The low-spin excitations of the nucleus {sup 146}Sm which is just two neutrons and two protons away from the N = 82 shell and Z = 64 subshell closures have been investigated by means of the {sup 143}Nd({alpha},n) and {sup 144}Nd({alpha},2n) fusion-evaporation reactions. We established 47 hitherto unknown energy levels up to 4.7MeV and 75 new transitions. In addition, 7 spin assignments were possible from the {gamma}-{gamma} angular correlation analysis. The structure of the possible candidates for a 2{sup +} x 3{sup -} quadrupole-octupole multiplet are first discussed in terms of the harmonic vibrational model. A comparison of these states with the corresponding ones in the neighboring N=84 isotones is also presented. Finally, the structure of the {sup 146}Sm nucleus is interpreted in terms of the IBA-spdf model. It is shown that the model is able to reproduce the experimental relative transition strengths of the 2{sup +} x 3{sup -} quadrupole-octupole multiplet and also a series of collective properties such as the proposed double-octupole excitations. (orig.)
Coulomb excitation of the two proton-hole nucleus $^{206}$Hg
We propose to use Coulomb excitation of the single magic two-proton-hole nucleus $^{206}$Hg. In a single-step excitation both the first 2$^{+}$ and the highly collective octupole 3$^{-}$ states will be populated. Thus, information on both quadrupole and octupole collectivity will be gained in this neutron-rich nucleus. Due to the high beam intensity, we will be able to observe multi-step Coulomb excitation as well, providing further test on theoretical calculations. The results will be used to improve the predictive power of the shell model for more exotic nuclei as we move to lighter N=126 nuclei. The experiment will use the new HIE-ISOLDE facility and the MINIBALL array, and will take advantage of the recently developed $^{206}$Hg beam from the molten lead target.
Agbemava, S E; Ring, P
2016-01-01
A systematic investigation of octupole deformed nuclei is presented for even-even systems with $Z\\leq 106$ located between the two-proton and two-neutron drip lines. For this study we use five most up-to-date covariant energy density functionals of different types, with a non-linear meson coupling, with density dependent meson couplings, and with density-dependent zero-range interactions. Pairing correlations are treated within relativistic Hartree-Bogoliubov (RHB) theory based on an effective separable particle-particle interaction of finite range. This allows us to assess theoretical uncertainties within the present covariant models for the prediction of physical observables relevant for octupole deformed nuclei. In addition, a detailed comparison with the predictions of non-relativistic models is performed. A new region of octupole deformation, centered around $Z\\sim 98, N\\sim 196$ is predicted for the first time. In terms of its size in the $(Z,N)$ plane and the impact of octupole deformation on binding e...
Do nuclei go pear-shaped? Coulomb excitation of 220Rn and 224Ra at REX-ISOLDE (CERN
Directory of Open Access Journals (Sweden)
Scheck M.
2015-01-01
Full Text Available The IS475 collaboration conducted Coulomb-excitation experiments with post-accelerated radioactive 220Rn and 224Ra beams at the REX-ISOLDE facility. The beam particles (Ebeam: 2.83 MeV/u were Coulomb excited using 60Ni, 114Cd, and 120Sn scattering targets. De-excitation γ-rays were detected employing the Miniball array and scattered particles were detected in a silicon detector. Exploiting the Coulomb-excitation code GOSIA for each nucleus several matrix elements could be obtained from the measured γ-ray yields. The extracted ‹3−||E3||0+› matrix element allows for the conclusion that, while 220Rn represents an octupole vibrational system, 224Ra has already substantial octupole correlations in its ground state. This finding has implications for the search of CP-violating Schiff moments in the atomic systems of the adjacent odd-mass nuclei.
Energy Technology Data Exchange (ETDEWEB)
Antipov, S. A.; Nagaitsev, S.; Valishev, A.
2017-04-01
Fermilab is constructing the Integrable Optics Test Accelerator (IOTA) as the centerpiece of the Accelerator R&D Program towards high-intensity circular machines. One of the factors limiting the beam intensity in present circular accelerators is collective instabilities, which can be suppressed by a spread of betatron frequencies (tunes) through the Landau damping mechanism or by an external damper, if the instability is slow enough. The spread is usually created by octupole magnets, which introduce the tune dependence on the amplitude and, in some cases, by a chromatic spread (tune dependence on particle's momentum). The introduction of octupoles usually lead to a resonant behavior and a reduction of the dynamic aperture. One of the goals of the IOTA research program is to achieve a high betatron tune spread, while retaining a large dynamic aperture using conventional octupole magnets in a special but realistic accelerator configuration. In this report, we present results of computer simulations of an electron beam in the IOTA by particle tracking and the Frequency Map Analysis. The results show that the ring's octupole magnets can be configured to provide a betatron tune shift of 0.08 (for particles at large amplitudes) with the dynamical aperture of over 20 beam sigma for a 150-MeV electron beam. The influence of the synchrotron motion, lattice errors, and magnet imperfections is insignificant for the parameters and levels of tolerances set by the design of the ring. The described octupole insert could be beneficial for suppression of space-charge induced instabilities in high intensity machines.
Study of octupole deformation in n-rich Ba isotopes populated via $\\beta$-decay
We propose to exploit the unique capability of the ISOLDE facility to produce $^{150, 151, 152}$Cs beams to investigate their radioactive $\\beta$-decay to $^{150, 151, 152}$Ba. The interest to study this mass region is twofold: these nuclei are expected to show octupole deformations already in their low-lying state, secondly information on the $\\beta$-decay is needed for the nuclear astrophysical model. The experiment will be performed with the ISOLDE Decay Station (IDS) setup using the fast tape station of K.U.-Leuven, equipped with four Clover Germanium detectors, four LaBr$_{3}$(Ce) detectors and one LEP HPGe detector. Information on the $\\beta$-decay, such as lifetimes and delayed neutron-emission probabilities, will be extracted, together with the detailed spectroscopy of the daughter nuclei, via $\\gamma$-$\\gamma$-coincidences and lifetime measurement of specific states.
Energy Technology Data Exchange (ETDEWEB)
Bouneau, S.; Azaiez, F.; Duprat, J. [IPN, Orsay (France)] [and others
1996-12-31
The study of the superdeformed (SD) {sup 196}Pb nucleus has been revisited using the EUROGAM phase 2 spectrometer. In addition to the known yrast and two lowest excited SD bands, a third excited SD band has been seen. All of the three excited bands were found to decay to the yrast SD band through, presumably, E1 transitions, allowing relative spin and excitation energy assignments. Comparisons with calculations using the random-phase approximation suggest that all three excited bands can be interpreted as octupole vibrational structures.
Smirnova, N A; Mizusaki, T; Van Isacker, P; Smirnova, Nadya A.; Pietralla, Norbert; Mizusaki, Takahiro; Isacker, Piet Van
2000-01-01
The interrelation between the octupole phonon and the low-lyingproton-neutron mixed-symmetry quadrupole phonon in near-spherical nuclei isinvestigated. The one-phonon states decay by collective E3 and E2 transitionsto the ground state and by relatively strong E1 and M1 transitions to theisoscalar 2^+ state. We apply the proton-neutron version of the InteractingBoson Model including quadrupole and octupole bosons (sdf-IBM-2). Two F-spinsymmetric dynamical symmetry limits of the model, namely the vibrational andthe $\\gamma$-unstable ones, are considered. We derive analytical formulae forexcitation energies as well as B(E1), B(M1), B(E2) and B(E3) values for anumber of transitions between low-lying states. The model well reproduces manyknown transition strengths in the near spherical nuclei ^{142}Ce and ^{94}Mo.
Indication for a K/sup. pi. / = 0/sup -/ octupole band in /sup 150/Nd from electron scattering
Energy Technology Data Exchange (ETDEWEB)
Creswell, C.; Hirsch, A.; Bertozzi, W.; Heisenberg, J.; Kowalski, S.; Sargent, C.P.; Turchinetz, W.; Dieperink, A.
1978-11-01
Recent electron scattering results on the 0.850 MeV level of /sup 150/Nd, when analyzed in terms of the interacting boson model, are inconsistent with the interpretation of this level as a pure J/sup ..pi../(K) = 2/sup +/(0) state. Very recent (n,n'..gamma..) work has shown this level to be a 1/sup -/, 2/sup +/ doublet. Assuming this level to be the band head of a ''K/sup ..pi../ = 0/sup -/'' octupole band, a simple model is used to predict electron scattering form factors for the 0.850 MeV state and a 3/sup -/ octupole level observed at 0.931 MeV. Comparison is made between these predicted form factors and recent electron scattering data.
Excited States in Solution through Polarizable Embedding
DEFF Research Database (Denmark)
Olsen, Jógvan Magnus; Aidas, Kestutis; Kongsted, Jacob
2010-01-01
functional theory which we denote the PE-DFT method. It has been implemented in combination with time-dependent quantum mechanical linear and nonlinear response techniques, thus allowing for assessment of electronic excitation processes and dynamic ground- and excited-state molecular properties using......We present theory and implementation of an advanced quantum mechanics/molecular mechanics (QM/MM) approach using a fully self-consistent polarizable embedding (PE) scheme. It is a polarizable layered model designed for effective yet accurate inclusion of an anisotropic medium in a quantum...... mechanical calculation. The polarizable embedding potential is described by an atomistic representation including terms up to localized octupoles and anisotropic polarizabilities. It is generally applicable to any quantum chemical description but is here implemented for the case of Kohn−Sham density...
Core excitations across the neutron shell gap in 207Tl
Directory of Open Access Journals (Sweden)
E. Wilson
2015-07-01
Full Text Available The single closed-neutron-shell, one proton–hole nucleus 207Tl was populated in deep-inelastic collisions of a 208Pb beam with a 208Pb target. The yrast and near-yrast level scheme has been established up to high excitation energy, comprising an octupole phonon state and a large number of core excited states. Based on shell-model calculations, all observed single core excitations were established to arise from the breaking of the N=126 neutron core. While the shell-model calculations correctly predict the ordering of these states, their energies are compressed at high spins. It is concluded that this compression is an intrinsic feature of shell-model calculations using two-body matrix elements developed for the description of two-body states, and that multiple core excitations need to be considered in order to accurately calculate the energy spacings of the predominantly three-quasiparticle states.
A generalized Ramsey excitation scheme with suppressed light shift
Huntemann, N; Okhapkin, M; Tamm, Chr; Peik, E; Taichenachev, A V; Yudin, V I
2012-01-01
We experimentally investigate a recently proposed optical excitation scheme [V.I. Yudin et al., Phys. Rev. A 82, 011804(R)(2010)] that is a generalization of Ramsey's method of separated oscillatory fields and consists of a sequence of three excitation pulses. The pulse sequence is tailored to produce a resonance signal which is immune to the light shift and other shifts of the transition frequency that are correlated with the interaction with the probe field. We investigate the scheme using a single trapped 171Yb+ ion and excite the highly forbidden 2S1/2-2F7/2 electric-octupole transition under conditions where the light shift is much larger than the excitation linewidth, which is in the Hertz range. The experiments demonstrate a suppression of the light shift by four orders of magnitude and an immunity against its fluctuations.
Generalized Ramsey excitation scheme with suppressed light shift.
Huntemann, N; Lipphardt, B; Okhapkin, M; Tamm, Chr; Peik, E; Taichenachev, A V; Yudin, V I
2012-11-21
We experimentally investigate a recently proposed optical excitation scheme V. I. Yudin et al. [Phys. Rev. A 82, 011804(R) (2010)] that is a generalization of Ramsey's method of separated oscillatory fields and consists of a sequence of three excitation pulses. The pulse sequence is tailored to produce a resonance signal that is immune to the light shift and other shifts of the transition frequency that are correlated with the interaction with the probe field. We investigate the scheme using a single trapped ^{171}Yb^{+} ion and excite the highly forbidden (2)S(1/2) - (2)F(7/2) electric-octupole transition under conditions where the light shift is much larger than the excitation linewidth, which is in the hertz range. The experiments demonstrate a suppression of the light shift by four orders of magnitude and an immunity against its fluctuations.
Space charge and octupole driven resonance trapping observed at the CERN proton synchrotron
Franchetti, Giuliano; Giovannozzi, Massimo; Martini, Michel; Métral, Elias
2003-01-01
The combined effect of space charge and nonlinear resonance on beam loss and emittance was measured in a benchmarking experiment over a 1.2 s long flat bottom at 1.4 GeV kinetic energy in the presence of a single controllable octupole. By lowering the working point towards the resonance, a gradual transition from a loss-free core emittance blowup to a regime dominated by continuous loss was found. We compare the observation with 3D simulations based on a new analytical space charge model and obtain good agreement in the emittance blowup regime. Our explanation is in terms of the synchrotron oscillation, which causes a periodic tune modulation due to space charge, and leads to trapping and detrapping on the resonance islands. For working points very close to the resonance this induces a beam halo with large radius. The underlying dynamics is studied in detail, and it is claimed that the predicted halo in conjunction with a reduced dynamic aperture for the real machine lattice is the source of the loss observed...
Core breaking and octupole low-spin states in $^{207}$ Tl
We propose to study the low-spin level structure of the $^{207}$Tl nucleus populated by the $\\beta$- decay of $^{207}$Hg. While $^{207}$Tl is a single-proton hole nucleus, the majority of the observed states will have a three-particle structure thus requiring the breaking of the neutron or proton core, or a collective octupole phonon coupled to the single proton hole. Thus information will be obtained on the single particle orbitals in the vicinity of the N=126 and Z=82 magic numbers, and on the size of the shell gap. The results will be used to improve the predictive power of the shell model for more exotic nuclei as we move to lighter N=126 nuclei.The experiment will use the ISOLDE Decay station, and will take advantage of the $^{207}$Hg beam from the molten lead target. A test on the feasibility to produce an $^{208}$Hg beam from the same target, with the aim to study the $\\beta$-decay into $^{208}$Tl, could be performed at the same time.
Energy Technology Data Exchange (ETDEWEB)
Chamon, L.C., E-mail: luiz.chamon@dfn.if.usp.b [Departamento de Fisica Nuclear, Instituto de Fisica da Universidade de Sao Paulo, Caixa Postal 66318, 05315-970, Sao Paulo, SP (Brazil); Carlson, B.V. [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Centro Tecnico Aeroespacial, Sao Jose dos Campos, SP (Brazil)
2010-11-30
We present a large-scale systematics of charge densities, excitation energies and deformation parameters for hundreds of heavy nuclei. The systematics is based on a generalized rotation-vibration model for the quadrupole and octupole modes and takes into account second-order contributions of the deformations as well as the effects of finite diffuseness values for the nuclear densities. We compare our results with the predictions of classical surface vibrations in the hydrodynamical approximation.
A comparison of two magnetic ultra-cold neutron trapping concepts using a Halbach-octupole array
Leung, K; Martin, F; Rosenau, F; Simson, M; Zimmer, O
2015-01-01
This paper describes a new magnetic trap for ultra-cold neutrons (UCNs) made from a 1.2 m long Halbach-octupole array of permanent magnets with an inner bore radius of 47 mm combined with an assembly of superconducting end coils and bias field solenoid. The use of the trap in a vertical, magneto-gravitational and a horizontal setup are compared in terms of the effective volume and ability to control key systematic effects that need to be addressed in high precision neutron lifetime measurements.
Magnetic octupole order in Ce0.7La0.3B6: A polarized neutron diffraction study
Kuwahara, K.; Iwasa, K.; Kohgi, M.; Aso, N.; Sera, M.; Iga, F.; Matsuura, M.; Hirota, K.
2009-09-01
Recently, in phase IV of CexLa1-xB6, weak but distinct superlattice reflections from the order parameter of phase IV have been detected by our unpolarized neutron scattering experiment [K. Kuwahara, K. Iwasa, M. Kohgi, N. Aso, M. Sera, F. Iga, J. Phys. Soc. Japan 76 (2007) 093702]. The scattering vector dependence of the intensity of superlattice reflections is quite unusual; the intensity is stronger for high scattering vectors. This result strongly indicates that the order parameter of phase IV is the magnetic octupole. However, the possibility that the observed superlattice reflections are due to lattice distortions could not be completely ruled out only on the basis of the unpolarized neutron scattering experiment. To confirm that the superlattice reflections are magnetic, therefore, we have performed a single crystal polarized neutron diffraction experiment on Ce0.7La0.3B6. The obtained result has clearly shown that the time reversal symmetry is broken by the order parameter of phase IV. This is further evidence for the magnetic octupole order in CexLa1-xB6.
Smith, J. F.; Simon, M. W.; Ibbotson, R. W.; Butler, P. A.; Aprahamian, A.; Bruce, A. M.; Cline, D.; Devlin, M.; Jones, G. D.; Jones, P. M.; Wu, C. Y.
1998-12-01
The lifetimes of 12 states in the opposite-parity bands of 153Eu have been measured using a recoil-distance technique following Coulomb excitation with a 220-MeV 58Ni beam. Electric-quadrupole (Q0) and -dipole (D0) moments, and intrinsic g factors (gK) have been extracted from the lifetimes. The Q0 and D0 values show very little dependence on spin and parity, and have the values of approximately 6.6 e b and 0.077 e fm, respectively. The gK values are found to differ for the positive- and negative-parity states. Although the large D0 values suggest a reflection-asymmetric octupole-deformed nuclear shape, the different gK values contradict this interpretation. A discussion of the nuclear structure of 153Eu in terms of potential parity-doublet bands and octupole deformation is given.
Bray, James William [Niskayuna, NY; Garces, Luis Jose [Niskayuna, NY
2012-03-13
The disclosed technology is a cryogenic static exciter. The cryogenic static exciter is connected to a synchronous electric machine that has a field winding. The synchronous electric machine is cooled via a refrigerator or cryogen like liquid nitrogen. The static exciter is in communication with the field winding and is operating at ambient temperature. The static exciter receives cooling from a refrigerator or cryogen source, which may also service the synchronous machine, to selected areas of the static exciter and the cooling selectively reduces the operating temperature of the selected areas of the static exciter.
Directory of Open Access Journals (Sweden)
M.V. Tkach
2015-09-01
Full Text Available The partial summing of infinite range of diagrams for the two-phonon mass operator of polaron described by Frohlich Hamiltonian is performed using the Feynman-Pines diagram technique. The renormalized spectral parameters of ground and first excited (phonon repeat polaron state are accurately calculated for the weak electron-phonon coupling at T=0 K. It is shown that the stronger electron-phonon interaction shifts the energy of both states into low-energy region of the spectra. The ground state stays stationary and the excited one - decays at bigger coupling constant.
Coexisting wobbling and quasiparticle excitations in the triaxial potential well of {sup 163}Lu
Energy Technology Data Exchange (ETDEWEB)
Jensen, D.R.; Hagemann, G.B.; Herskind, B.; Sletten, G.; Wilson, J.N. [Niels Bohr Institute, Blegdamsvej 17, DK-2100, Copenhagen (Denmark); Hamamoto, I. [Niels Bohr Institute, Blegdamsvej 17, DK-2100, Copenhagen (Denmark); Department of Mathematical Physics, LTH, University of Lund, Lund (Sweden); Oedegaard, S.W. [Department of Physics, University of Oslo, PB 1048 Blindern, N-0316, Oslo (Norway); Spohr, K. [Department of Electronic Engineering and Physics, University of Paisley (United Kingdom); Huebel, H.; Bringel, P.; Neusser, A.; Schoenwasser, G.; Singh, A.K. [Helmholtz-Institut fuer Strahlen- und Kernphysik, University of Bonn, Nussallee 14-16, D-53115, Bonn (Germany); Ma, W.C.; Amro, H. [Mississippi State University, MS 39762, Mississippi State (United States); Bracco, A.; Leoni, S.; Benzoni, G. [Dipartimento di Fisica and INFN, Sezione di Milano, Milano (Italy); Maj, A. [Niewodniczanski Insitute of Nuclear Physics, Krakow (Poland); Petrache, C.M. [Dipartimento di Fisica and INFN, Sezione di Padova, Padova (Italy); Dipartimento di Matematica e Fisica, Universita di Camerino, Camerino (Italy); Lo Bianco, G.; Bednarczyk, P.; Curien, D.
2004-02-01
High-spin states of the nucleus {sup 163}Lu have been populated through the fusion-evaporation reaction {sup 139}La({sup 29}Si,5n) with a beam energy of 157 MeV. In addition to the two lowest excited triaxial strongly deformed (TSD) bands, recently interpreted as one- and two-phonon wobbling excitations, a third excited TSD band has been firmly established decaying to the yrast TSD band. The assignment of this band as a three-quasiparticle band shows together with the normal deformed (ND) level scheme the presence not only of shape coexistence between ND and TSD structures, but also an interplay of wobbling and quasiparticle excitations in the triaxial strongly deformed potential well of {sup 163}Lu. (orig.)
Mcpeak, W. L.
1975-01-01
A new exciter switch assembly has been installed at the three DSN 64-m deep space stations. This assembly provides for switching Block III and Block IV exciters to either the high-power or 20-kW transmitters in either dual-carrier or single-carrier mode. In the dual-carrier mode, it provides for balancing the two drive signals from a single control panel located in the transmitter local control and remote control consoles. In addition to the improved switching capabilities, extensive monitoring of both the exciter switch assembly and Transmitter Subsystem is provided by the exciter switch monitor and display assemblies.
Feldman, Hume A; Hudson, Michael J
2009-01-01
The low order moments of the large scale peculiar velocity field are sensitive probes of the matter density fluctuations on very large scales. However, peculiar velocity surveys have varying spatial distributions of tracers, and so the moments estimated are hard to model and thus are not directly comparable between surveys. In addition, the sparseness of typical proper distance surveys can lead to aliasing of small scale power into what is meant to be a probe of the largest scales. Here we extend our previous optimization analysis of the bulk flow to include the shear and octupole moments where velocities are weighted to give an optimal estimate of the moments of an idealized survey, with the variance of the difference between the estimate and the actual flow being minimized. These "minimum variance" (MV) estimates can be designed to calculate the moments on a particular scale with minimal sensitivity to small scale power, and thus different surveys can be directly compared. The MV moments were also designed ...
Leung, K K H; Ivanov, S; Rosenau, F; Zimmer, O
2016-01-01
Ultracold neutron (UCN) storage measurements were made in a trap constructed from a 1.3 T Halbach Octupole PErmanent (HOPE) magnet array aligned vertically, using the TES-port of the PF2 source at the Institut Laue-Langevin. A mechanical UCN valve at the bottom of the trap was used for filling and emptying. This valve was covered with Fomblin grease to induce non-specular reflections and was used in combination with a movable polyethylene UCN remover inserted from the top for cleaning of above-threshold UCNs. Loss due to UCN depolarization was suppressed with a minimum 2 mT bias field. Without using the UCN remover, a total storage time constant of $(712 \\pm 19)$ s was observed; with the remover inserted for 80 s and used at either 80 cm or 65 cm from the bottom of the trap, time constants of $(824 \\pm 32)$ s and $(835 \\pm 36)$ s were observed. Combining the latter two values, a neutron lifetime of $\\tau_{\\rm n} = (887 \\pm 39)$ s is extracted after primarily correcting for losses at the UCN valve. The time co...
Lim, Edward C
1974-01-01
Excited States, Volume I reviews radiationless transitions, phosphorescence microwave double resonance through optical spectra in molecular solids, dipole moments in excited states, luminescence of polar molecules, and the problem of interstate interaction in aromatic carbonyl compounds. The book discusses the molecular electronic radiationless transitions; the double resonance techniques and the relaxation mechanisms involving the lowest triplet state of aromatic compounds; as well as the optical spectra and relaxation in molecular solids. The text also describes dipole moments and polarizab
Pressure dependence of donor excitation spectra in AlSb
Energy Technology Data Exchange (ETDEWEB)
Hsu, L.; McCluskey, M.D.; Haller, E.E.
2002-01-16
We have investigated the behavior of ground to bound excited-state electronic transitions of Se and Te donors in AlSb as a function of hydrostatic pressure. Using broadband far-infrared Fourier transform spectroscopy, we observe qualitatively different behaviors of the electronic transition energies of the two donors. While the pressure derivative of the Te transition energy is small and constant, as might be expected for a shallow donor, the pressure derivatives of the Se transition energies are quadratic and large at low pressures, indicating that Se is actually a deep donor. In addition, at pressures between 30 and 50 kbar, we observe evidence of an anti-crossing between one of the selenium electronic transitions and a two-phonon mode.
Energy Technology Data Exchange (ETDEWEB)
Trabert, E; Beiersdorfer, P; Brown, G V
2006-12-21
We present measurements of high statistical significance of the rate of the magnetic octupole (M3) decay in nickel-like ions of isotopically pure {sup 129}Xe and {sup 132}Xe. On {sup 132}Xe, an isotope with zero nuclear spin and therefore without hyperfine structure, the lifetime of the metastable level was established as (15.06 {+-} 0.24) ms. On {sup 129}Xe, an additional fast (2.7 {+-} 0.1 ms) decay component was established that represents hyperfine mixing with a level that decays by electric quadrupole (E2) radiation.
Faye, Guillaume; Iyer, Bala R
2014-01-01
This paper is motivated by the need to improve the post-Newtonian (PN) amplitude accuracy of waveforms for gravitational waves generated by inspiralling compact binaries, both for use in data analysis and in the comparison between post-Newtonian approximations and numerical relativity computations. It presents: (i) the non-linear couplings between multipole moments of general post-Newtonian matter sources up to order 3.5PN, including all contributions from tails, tails-of-tails and the non-linear memory effect; and (ii) the source mass-type octupole moment of (non-spinning) compact binaries up to order 3PN, which permits to complete the expressions of the octupole modes (3,3) and (3,1) of the gravitational waveform to order 3.5PN. At this occasion we reconfirm by means of independent calculations our earlier results concerning the source mass-type quadrupole moment to order 3PN. Related discussions on factorized resummed waveforms and the occurence of logarithmic contributions to high order are also included.
Faye, Guillaume; Blanchet, Luc; Iyer, Bala R.
2015-02-01
This paper is motivated by the need to improve the post-Newtonian (PN) amplitude accuracy of waveforms for gravitational waves generated by inspiralling compact binaries, both for use in data analysis and in the comparison between post-Newtonian approximations and numerical relativity computations. It presents (i) the non-linear couplings between multipole moments of general post-Newtonian matter sources up to order 3.5PN, including all contributions from tails, tails-of-tails and the non-linear memory effect; and (ii) the source mass-type octupole moment of (non-spinning) compact binaries up to order 3PN, which permits completion of the expressions of the octupole modes (3,3) and (3,1) of the gravitational waveform to order 3.5PN. On this occasion we reconfirm by means of independent calculations our earlier results concerning the source mass-type quadrupole moment to order 3PN. Related discussions on factorized resummed waveforms and the occurence of logarithmic contributions to high order are also included.
Energy Technology Data Exchange (ETDEWEB)
Mukhopadhyay, N.C.
1986-01-01
The status of the theory of the low-energy approach to hadron structure is reviewed briefly by surveying a few relevant models. A few examples of tests needed to sort out the predictions of different models pertaining to the quark-gluon structure of hadrons are discussed, and given the resulting physics objectives, a few experimental options for excited baryon research at CFBAF are suggested. (LEW)
Excitations of one-valence-proton, one-valence-neutron nucleus {sup 210}Bi from cold-neutron capture
Energy Technology Data Exchange (ETDEWEB)
Cieplicka-Oryńczak, N. [INFN sezione di Milano, Via Celoria 16, 20133 Milano (Italy); Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Kraków (Poland); Fornal, B.; Szpak, B. [Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Kraków (Poland); Leoni, S.; Bottoni, S. [INFN sezione di Milano, Via Celoria 16, 20133 Milano (Italy); Università degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy); Bazzacco, D. [Dipartimento di Fisica e Astronomia dell’Università, I-35131 Padova (Italy); INFN Sezione di Padova, I-35131 Padova (Italy); Blanc, A.; Jentschel, M.; Köster, U.; Mutti, P.; Soldner, T. [Institute Laue-Langevin, 6, rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Bocchi, G. [Università degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy); France, G. de [GANIL, Bd. Becquerel, BP 55027, 14076 CAEN Cedex 05 (France); Simpson, G. [LPSC, Université Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut National Polytechnique de Grenoble, F-38026 Grenoble Cedex (France); Ur, C. [INFN Sezione di Padova, Via F. Marzolo 8, I-35131 Padova (Italy); Urban, W. [Faculty of Physics, University of Warsaw, ul. Hoża 69, 02-681, Warszawa (Poland)
2015-10-15
The low-spin structure of one-proton, one-neutron {sup 210}Bi nucleus was investigated in cold-neutron capture reaction on {sup 209}Bi. The γ-coincidence measurements were performed with use of EXILL array consisted of 16 HPGe detectors. The experimental results were compared to shell-model calculations involving valence particles excitations. The {sup 210}Bi nucleus offers the potential to test the effective proton-neutron interactions because most of the states should arise from the proton-neutron excitations. Additionally, it was discovered that a few states should come from the couplings of valence particles to the 3{sup −} octupole vibration in {sup 208}Pb which provides also the possibility of testing the calculations involving the core excitations.
Low-spin excitations in {sup 98}Ru
Energy Technology Data Exchange (ETDEWEB)
Radeck, Desiree; Albers, Michael; Bernards, Christian; Fransen, Christoph; Jolie, Jan; Muecher, Dennis [Institut fuer Kernphysik, Universitaet Koeln (Germany)
2009-07-01
In the context of collectivity in the A=100 mass region N=52 isotones were investigated in detail and phonon excitations - especially the mixed-symmetry (MS) states - were identified. In order to investigate how states with this MS character evolve with increasing valence neutron number N=54 isotones were studied. While in {sup 96}Mo the one-phonon MS state 2{sup +}{sub 1,ms} was identified, {sup 98}Ru shows a breakdown of vibrational structure above the two-phonon triplet and no candidate for the 2{sup +}{sub 1,ms} state was assigned. The recently investigated N=54 isotone {sup 100}Pd was explained well with an U{sub {pi}}{sub {nu}}(5) fit within the IBM-2. Furthermore, a candidate for the one-phonon MS2{sup +}{sub 1,ms} state was determined. To do further investigations on the N=54 isotone {sup 98}Ru - in particular regarding the breakdown of vibrational symmetry and the one-phonon MS excitation - an experiment was performed at the Cologne Tandem Accelerator using the HORUS spectrometer. The nuclei were populated by the reaction {sup 97}Mo({sup 3}He,2n){sup 98}Ru. By analysing the coincidence and {gamma}{gamma} angular correlation data the level scheme was extended and clarified by determining spins, multipole mixing ratios and branching ratios. The low-energy excitations of positive parity are discussed and compared to theoretical expectations. The results are compared with those for other N=54 isotones.
Stoller, R J
1976-08-01
Sexual excitement depends on a scenario the person to be aroused has been writing since childhood. The story is an adventure, an autobiography disguised as fiction, in which the hero/heroine hides crucial intrapsychic conflicts, mysteries, screen memories of actual traumatic events and the resolution of these elements into a happy ending, best celebrated by orgasm. The function of the fantasy is to take these painful experiences and convert them to pleasure-triumph. In order to sharpen excitement-the vibration between the fear of original traumas repeating and the hope of a pleasurable conclusion this time-one introduces into the story elements of risk (approximations of the trauma) meant to prevent boredom and safety factors (sub-limnal signals to the storyteller that the risk are not truly dangerous). Sexual fantasy can be studied by means of a person's daydreams (including those chosen in magazines, books, plays, television, movies, and outright pornography), masturbatory behavior, object choice, foreplay, techniques of intercourse, or postcoital behavior.
Gamma-decay study of {sup 21}Na and {sup 21}Ne, octupole bands in {sup 21}Ne
Energy Technology Data Exchange (ETDEWEB)
Thummerer, S [Hahn-Meitner-Institut, Berlin (Germany); Oertzen, W von [Hahn-Meitner-Institut, Berlin (Germany); Kokalova, Tz [Hahn-Meitner-Institut, Berlin (Germany); Bohlen, H G [Hahn-Meitner-Institut, Berlin (Germany); Gebauer, B [Hahn-Meitner-Institut, Berlin (Germany); Tumino, A [Hahn-Meitner-Institut, Berlin (Germany); Massey, T N [Department of Physics and Astronomy, Ohio University, Athens, OH (United States); Angelis, G de [Hahn-Meitner-Institut, Berlin (Germany); Axiotis, M [INFN, Laboratori Nazionali di Legnaro, Legnaro (PD) (Italy); Gadea, A [INFN, Laboratori Nazionali di Legnaro, Legnaro (PD) (Italy); Kroell, Th [INFN, Laboratori Nazionali di Legnaro, Legnaro (PD) (Italy); Marginean, N [INFN, Laboratori Nazionali di Legnaro, Legnaro (PD) (Italy); Napoli, D R [INFN, Laboratori Nazionali di Legnaro, Legnaro (PD) (Italy); Poli, M De [INFN, Laboratori Nazionali di Legnaro, Legnaro (PD) (Italy); Ur, C [INFN, Laboratori Nazionali di Legnaro, Legnaro (PD) (Italy); Bazzacco, D [Dipartimento di Fisica and INFN, Padova (Italy); Lenzi, S M [Dipartimento di Fisica and INFN, Padova (Italy); Alvarez, C Rossi [Dipartimento di Fisica and INFN, Padova (Italy); Lunardi, S [Dipartimento di Fisica and INFN, Padova (Italy); Menegazzo, R [Dipartimento di Fisica and INFN, Padova (Italy); Bizzeti, P G [Dipartimento di Fisica and INFN, Florence (Italy); Bizzeti-Sona, A M [Dipartimento di Fisica and INFN, Florence (Italy)
2003-03-01
The reactions {sup 16}O({sup 7}Li, 2n) and {sup 16}O({sup 7}Li, np) populating {sup 21}Na and {sup 21}Ne have been studied at E{sub L} = 27 MeV using the GASP {gamma}-detector array. The level scheme for {sup 21}Na and {sup 21}Ne has been extended to higher excitation energy. Spins and parities of the observed levels are assigned tentatively supporting the identification of opposite parity structures connected by strong dipole transitions. The structure of these bands is interpreted as based on a reflection asymmetric cluster structure.
RESONANT CAVITY EXCITATION SYSTEM
Baker, W.R.; Kerns, Q.A.; Riedel, J.
1959-01-13
An apparatus is presented for exciting a cavity resonator with a minimum of difficulty and, more specifically describes a sub-exciter and an amplifier type pre-exciter for the high-frequency cxcitation of large cavities. Instead of applying full voltage to the main oscillator, a sub-excitation voltage is initially used to establish a base level of oscillation in the cavity. A portion of the cavity encrgy is coupled to the input of the pre-exciter where it is amplified and fed back into the cavity when the pre-exciter is energized. After the voltage in the cavity resonator has reached maximum value under excitation by the pre-exciter, full voltage is applied to the oscillator and the pre-exciter is tunned off. The cavity is then excited to the maximum high voltage value of radio frequency by the oscillator.
El-Kader, M. S. A.; Kalugina, Y. N.
2015-10-01
The dipole-quadrupole and dipole-octupole polarizabilities of CCl4 have been determined from collision-induced light scattering (CILS) spectrum. (Hyper)polarizabilities were calculated at the CCSD(T) level of theory with aug-cc-pVXZ (X = D, T, Q) basis sets. The CILS spectra were analyzed using our new intermolecular potential and those available in literature. The quality of the present potential was checked by comparison between calculated and experimental thermophysical and transport properties over a wide temperature range. Our final estimates from experiment for these properties are |A|=62.7 a.u. and |E|=423.8 a.u. and the theoretical values of (hyper)polarizabilities calculated at the CCSD(T)/aug-cc-pVQZ level of theory are α = 69.27 a.u., A = 67.15 a.u., E = -203.97 a.u., C = 821.75 a.u., β = 11.88 a.u., and γ = 10 768.6 a.u.
Lu, Bing-Nan; Zhao, En-Guang; Zhou, Shan-Gui
2013-01-01
We have developed multi-dimensional constrained covariant density functional theories (MDC-CDFT) for finite nuclei in which the shape degrees of freedom \\beta_{\\lambda\\mu} with even \\mu, e.g., \\beta_{20}, \\beta_{22}, \\beta_{30}, \\beta_{32}, \\beta_{40}, etc., can be described simultaneously. The functional can be one of the following four forms: the meson exchange or point-coupling nucleon interactions combined with the non-linear or density-dependent couplings. For the pp channel, either the BCS approach or the Bogoliubov transformation is implemented. The MDC-CDFTs with the BCS approach for the pairing (in the following labelled as MDC-RMF models with RMF standing for "relativistic mean field") have been applied to investigate multi-dimensional potential energy surfaces and the non-axial octupole $Y_{32}$-correlations in N=150 isotones. In this contribution we present briefly the formalism of MDC-RMF models and some results from these models. The potential energy surfaces with and without triaxial deformatio...
Study of octupole-deformed K=1/2 bands in sup 2 sup 2 sup 7 Th High spin states
Hammond, N
2002-01-01
High spin states in sup 2 sup 2 sup 7 Th have been populated using the reaction sup 2 sup 2 sup 6 Ra(alpha,3n) sup 2 sup 2 sup 7 Th at a bombarding energy of 33 MeV. The high-spin rotational structures of this nucleus have been refined and extended. In addition, the linking of these structures with the low-spin states known from sup 2 sup 3 sup 1 U alpha decay has allowed a comprehensive decay scheme of this nucleus to be assembled for the first time. Four previously known rotational bands are interpreted as Coriolis-coupled K suppi = 1/2 sup + and K suppi = 1/2 sup - bands, in agreement with predictions using a reflection-asymmetric mean-field approach. The determination of decoupling parameters for these bands is consistent with the a(K suppi = 1/2 sup +) = -a(K suppi = 1/2 sup -) rigid-octupole-rotor expectation. A further rotational band is interpreted as having K suppi = 3/ sup - . Measured D sub 0 /Q sub 0 ratios are consistent with an interpolation, of the values given for neighbouring even-even nuclei...
a simple a simple excitation control excitation control excitation ...
African Journals Online (AJOL)
eobe
brushes for low power generators or brushless for high-power ... produce the primary dc fluxes are usually placed on the ... motor and the study was extended to over-excitation schemes ... automatic voltage controller (AVR) around this range.
Scheck, M; Brentano, P V
2002-01-01
In this contribution the focus is on the systematic study of [2 sup + x3 sup -] sub 1 -two-phonon excitations around the Z = 50 and N = 82 shell closures. The results for the Sn and Ba isotope chains will be shown in a general framework of all available data obtained by nuclear resonance fluorescence experiments. The photon scattering experiments referred to in this work were performed at the Bremsstrahlung facility of the 4.3 MV Stuttgart Dynamitron accelerator. NRF experiments are suitable for the determination of excitation energies, spins, lifetimes and transition strengths of low-spin states. The even-even isotopes show strong 1 sup - excitations close to the sum energy of the 2 sup + and 3 sup - phonons, interpreted as [2 sup + x3 sup -] sub 1 -two phonon excitations. The behaviour of these [2 sup + x 3 sup -] sub 1 -states in even-even nuclei can be explained by the so-called DCP effect. Furthermore, the coupling of a single nucleon to this collective excitation in the neighbouring odd-mass nuclei is i...
All-dielectric nanoantennas for unidirectional excitation of electromagnetic guided modes
Lee, Sergey; Krasnok, Alexander; Belov, Pavel
2015-01-01
Engineering of intensity and direction of radiation from a single quantum emitter by means of structuring of their environment at the nanoscale is at the cornerstone of modern nanophotonics. Recently discovered systems exhibiting spin--orbit coupling of light are of particular interest in this context. In this Letter, we have demonstrated that asymmetrical excitation of a high-index subwavelength dielectric nanoparticle by a point dipole source located in a notch at its surface results in formation of a chiral near field, which is similar to that of a circularly polarized dipole or quadrupole. Using numerical simulations, we have shown that this effect is the result of a higher multipole (quadrupole and octupole) modes excitation within the nanoparticle. We have applied this effect for unidirectional excitation of dielectric waveguide and surface plasmon-polariton modes. We have achieved the value of front--to--back ratio up to 5.5 for dielectric waveguide and to 7.5 for the plasmonic one. Our results are imp...
Beecher, L. C.; Williams, F. T.
1970-01-01
Gas-driven vibration exciter produces a sinusoidal excitation function controllable in frequency and in amplitude. It allows direct vibration testing of components under normal loads, removing the possibility of component damage due to high static pressure.
Younis, Mohammad I.
2016-03-10
Embodiments of multi-frequency excitation are described. In various embodiments, a natural frequency of a device may be determined. In turn, a first voltage amplitude and first fixed frequency of a first source of excitation can be selected for the device based on the natural frequency. Additionally, a second voltage amplitude of a second source of excitation can be selected for the device, and the first and second sources of excitation can be applied to the device. After applying the first and second sources of excitation, a frequency of the second source of excitation can be swept. Using the methods of multi- frequency excitation described herein, new operating frequencies, operating frequency ranges, resonance frequencies, resonance frequency ranges, and/or resonance responses can be achieved for devices and systems.
Palazzi, E.; Mandolesi, N.; Crane, Philippe
1992-10-01
We report the results of a search for new lines of sight in which to study the CN excitation and a statistical analysis of all the excitation temperatures measured using interstellar CN. This data set strongly confirms that the cosmic background radiation (CBR) is the dominant contributor to the excitation of CN, and demonstrates the homogeneity of the CBR. Thirty-five observations is a sufficiently large sample to look for the presence of systematic effects in the CN excitation. The weighted average of the CN excitation temperatures exceeds the T(CBR) obtained by COBE and the Canadian rocket by 82 +/- 30 mK. With the aim of looking at the origin of this difference, we have considered in detail the known mechanisms that could contribute to exciting the CN molecule. None of the data necessary to quantify these mechanisms are of sufficient quality to provide a clean explanation of the observed difference.
Kubo, Tetsuro; Kotegawa, Hisashi; Tou, Hideki; Higashinaka, Ryuji; Nakama, Akihiro; Aoki, Yuji; Sato, Hideyuki
2015-07-01
We report measurements of bulk magnetic susceptibility and 93Nb nuclear quadrupole resonance (NQR) in the Pr-based caged compound PrNb2Al20. By analyzing the magnetic susceptibility and magnetization, the crystal electric field (CEF) level scheme of PrNb2Al20 is determined to be Γ3(0 K)-Γ4(21.32 K)-Γ5(43.98 K)-Γ1(51.16 K) within the framework of the localized 4f electron picture. The 93Nb-NQR spectra exhibit neither spectral broadening nor spectral shift upon cooling down to 75 mK. The 93Nb-NQR spin-lattice relaxation rate 1/T1 at 5 K depends on the frequency and remains almost constant below 5 K. The frequency dependence of 1/T1 is attributed to the magnetic fluctuation due to the hyperfine-enhanced 141Pr nuclear moment inherent in the nonmagnetic Γ3 CEF ground state. The present NQR results provide evidence that no symmetry-breaking magnetic dipole order occurs down to 75 mK. Also, considering an invariant form of the quadrupole and octupole couplings between a 93Nb nucleus and Pr 4f electrons, Pr 4f quadrupoles and an octupole can couple with a 93Nb nuclear quadrupole moment and nuclear spin, respectively. Together with the results of bulk measurements, the present NQR results suggest that the possibility of a static quadrupole or octupole ordering can be excluded down to 100 mK. At low temperatures below 500 mK, however, the nuclear spin-echo decay rate gradually increases and the decay curve changes from Gaussian decay to Lorentzian decay, suggesting the evolution of a low-energy excitation.
Lim, Edward C
2013-01-01
Excited States, Volume 2 is a collection of papers that deals with molecules in the excited states. The book describes the geometries of molecules in the excited electronic states. One paper describes the geometries of a diatomic molecule and of polyatomic molecules; it also discusses the determination of the many excited state geometries of molecules with two, three, or four atoms by techniques similar to diatomic spectroscopy. Another paper introduces an ordered theory related to excitons in pure and mixed molecular crystals. This paper also presents some experimental data such as those invo
Lim, Edward C
1982-01-01
Excited States, Volume 6 is a collection of papers that discusses the excited states of molecules. The first paper discusses the linear polyene electronic structure and potential surfaces, considering both the theoretical and experimental approaches in such electronic states. This paper also reviews the theory of electronic structure and cites some experimental techniques on polyene excitations, polyene spectroscopic phenomenology, and those involving higher states of polyenes and their triplet states. Examples of these experimental studies of excited states involve the high-resolution one-pho
Influence of multiphonon excitations and transfer on the fusion of Ca+Zr
Esbensen, H
2014-01-01
Fusion data for $^{48}$Ca+$^{90,96}$Zr are analyzed by coupled-channels calculations that are based on the M3Y+repulsion, double-folding potential. By applying a previously determined nuclear density of $^{48}$Ca, the neutron densities of the zirconium isotopes are adjusted to optimize the fit to the fusion data, whereas the proton densities are determined by electron scattering experiments. It is shown that the fusion data can be explained fairly well by including couplings to one- and two-phonon excitations of the reacting nuclei and to one- and two-nucleon transfer reactions but there is also some sensitivity to multiphonon excitations. The neutron skin thicknesses extracted for the two zirconium isotopes are consistent with anti-proton measurements. The densities of the zirconium isotopes are used together with the previously determined nuclear density of $^{40}$Ca to calculate the M3Y+repulsion potentials and predict the fusion cross sections of $^{40}$Ca+$^{90,96}$Zr. The predicted cross sections for $^...
Single- and multi-phonon excitations of $\\gamma$ vibration in rotating odd-$A$ nuclei
Matsuzaki, Masayuki
2014-01-01
Collective motions in quantum many-body systems are described as bosonic excitations. Multi-phonon excitations in atomic nuclei, however, were observed very rarely. In particular, the first two-phonon \\gamma vibration (2\\gamma) in odd-A nuclei was reported in 2006 and only a few have been known. Two theoretical calculations for the data on Nb103 were done, one of which was done by the present author within a limited model space. Quite recently, conspicuously enhanced B(E2) feeding the 2\\gamma were observed in Nb105 and conjectured that their mother states are candidates of 3\\gamma. In the present work, the model space is enlarged up to 4\\gamma states. The purposes are two-folds: One is to see how the description in the previous work is improved, and the other is to look into the existence of 3\\gamma states, and when they exist, study their collectivity through calculating interband B(E2). The particle-vibration coupling model based on the cranking model and the random-phase approximation is used to calculate ...
Lim, Edward C
2013-01-01
Excited States, Volume 4 is a collection of papers that deals with the excited states of molecular activity. One paper investigates the resonance Raman spectroscopy as the key to vibrational-electronic coupling. This paper reviews the basic theory of Raman scattering; it also explains the derivation of the Raman spectra, excitation profiles, and depolarization ratios for simple resonance systems. Another paper reviews the magnetic properties of triplet states, including the zero-field resonance techniques, the high-field experiments, and the spin Hamiltonian. This paper focuses on the magnetic
Copelli, Mauro
2007-01-01
When a simple excitable system is continuously stimulated by a Poissonian external source, the response function (mean activity versus stimulus rate) generally shows a linear saturating shape. This is experimentally verified in some classes of sensory neurons, which accordingly present a small dynamic range (defined as the interval of stimulus intensity which can be appropriately coded by the mean activity of the excitable element), usually about one or two decades only. The brain, on the other hand, can handle a significantly broader range of stimulus intensity, and a collective phenomenon involving the interaction among excitable neurons has been suggested to account for the enhancement of the dynamic range. Since the role of the pattern of such interactions is still unclear, here we investigate the performance of a scale-free (SF) network topology in this dynamic range problem. Specifically, we study the transfer function of disordered SF networks of excitable Greenberg-Hastings cellular automata. We obser...
Tetrahedral symmetry in Zr nuclei: Calculations of low-energy excitations with Gogny interaction
Tagami, Shingo; Dudek, Jerzy
2014-01-01
We report on the results of the calculations of the low energy excitation patterns for three Zirconium isotopes, viz. $^{80}$Zr$_{40}$, $^{96}$Zr$_{56}$ and $^{110}$Zr$_{70}$, reported by other authors to be doubly-magic tetrahedral nuclei (with tetrahedral magic numbers $Z$=40 and $N$=40, 56 and 70). We employ the realistic Gogny effective interactions using three variants of their parametrisation and the particle-number, parity and the angular-momentum projection techniques. We confirm quantitatively that the resulting spectra directly follow the pattern expected from the group theory considerations for the tetrahedral symmetric quantum objects. We also find out that, for all the nuclei studied, the correlation energy obtained after the angular momentum projection is very large for the tetrahedral deformation as well as other octupole deformations. The lowering of the energies of the resulting configurations is considerable, i.e. by about 10 MeV or even more, once again confirming the significance of the an...
Stojanović, Ljiljana; Alyoubi, Abdulrahman O.; Aziz, Saadullah G.; Hilal, Rifaat H.; Barbatti, Mario
2016-11-01
In the present study, we examined the UV excitations of a newly introduced molecular set, Halons-9, composed of nine gaseous halon molecules. The performance of the density functional-based multi-reference configuration interaction method (DFT/MRCI) and time-dependent density functional theory with CAM-B3LYP functional (TD-CAM-B3LYP) in the computation of singlet and triplet excited states of this set was evaluated against coupled-cluster with singles and doubles (CCSD). Excited states up to the corresponding ionization limits, including both localized and delocalized excitations, have been benchmarked. TD-CAM-B3LYP significantly underestimates excitation energies of the higher mixed valence-Rydberg and Rydberg states, with computed mean absolute deviations from the equation of motion (EOM)-CCSD results 1.06 and 0.76 eV, respectively. DFT/MRCI gives a significantly better description of higher excited states, albeit still poor, compared to the TD-CAM-B3LYP. The mean absolute deviations of mixed valence-Rydberg and Rydberg states from the reference EOM-CCSD values are 0.66 and 0.47 eV, respectively. The performance of DFT/MRCI for description of strongly correlated states with valence-Rydberg mixing is still not satisfactory enough. On the other hand, oscillator strengths of most of singlet states obtained with both methods are close to the EOM-CCSD values. The largest deviations, occurring in the case of several high-lying multiconfigurational states, are of an order of magnitude.
Hardness and excitation energy
Indian Academy of Sciences (India)
Á Nagy
2005-09-01
The concept of the ensemble Kohn-Sham hardness is introduced. It is shown that the first excitation energy can be given by the Kohn-Sham hardness (i.e. the energy difference of the ground-state lowest unoccupied and highest occupied levels) plus an extra term coming from the partial derivative of the ensemble exchange-correlation energy with respect to the weighting factor in the limit → 0. It is proposed that the first excitation energy can be used as a reactivity index instead of the hardness.
Agranovich, Vladimir M
2009-01-01
During the last decade our expertise in nanotechnology has advanced considerably. The possibility of incorporating in the same nanostructure different organic and inorganic materials has opened up a promising field of research, and has greatly increased the interest in the study of properties of excitations in organic materials. In this book not only the fundamentals of Frenkel exciton and polariton theory are described, but also the electronic excitations and electronic energytransfers in quantum wells, quantum wires and quantum dots, at surfaces, at interfaces, in thin films, in multilayers,
Excitation Methods for Bridge Structures
Energy Technology Data Exchange (ETDEWEB)
Farrar, C.R.; Duffy, T.A.; Cornwell, P.J.; Doebling, S.W.
1999-02-08
This paper summarizes the various methods that have been used to excited bridge structures during dynamic testing. The excitation methods fall into the general categories of ambient excitation methods and measured-input excitation methods. During ambient excitation the input to the bridge is not directly measured. In contrast, as the category label implies, measured-input excitations are usually applied at a single location where the force input to the structure can be monitored. Issues associated with using these various types of measurements are discussed along with a general description of the various excitation methods.
Fuzzballs with internal excitations
Energy Technology Data Exchange (ETDEWEB)
Kanitscheider, Ingmar; Skenderis, Kostas; Taylor, Marika [Institute for Theoretical Physics, University of Amsterdam, Valckenierstraat 65, 1018XE Amsterdam (Netherlands)
2007-06-15
We construct general 2-charge D1-D5 horizon-free non-singular solutions of IIB supergravity on T{sup 4} and K3 describing fuzzballs with excitations in the internal manifold; these excitations are characterized by arbitrary curves. The solutions are obtained via dualities from F1-P solutions of heterotic and type IIB on T{sup 4} for the K3 and T{sup 4} cases, respectively. We compute the holographic data encoded in these solutions, and show that the internal excitations are captured by vevs of chiral primaries associated with the middle cohomology of T{sup 4} or K3. We argue that each geometry is dual to a specific superposition of R ground states determined in terms of the Fourier coefficients of the curves defining the supergravity solution. We compute vevs of chiral primaries associated with the middle cohomology and show that they indeed acquire vevs in the superpositions corresponding to fuzzballs with internal excitations, in accordance with the holographic results. We also address the question of whether the fuzzball program can be implemented consistently within supergravity.
Excitation of Stellar Pulsations
DEFF Research Database (Denmark)
Houdek, G.
2012-01-01
In this review I present an overview of our current understanding of the physical mechanisms that are responsible for the excitation of pulsations in stars with surface convection zones. These are typically cooler stars such as the δ Scuti stars, and stars supporting solar-like oscillations....
Decoherence at constant excitation
Torres, J. M.; Sadurní, E.; Seligman, T. H.
2012-02-01
We present a simple exactly solvable extension of the Jaynes-Cummings model by adding dissipation. This is done such that the total number of excitations is conserved. The Liouville operator in the resulting master equation can be reduced to blocks of 4×4 matrices.
Decoherence at constant excitation
Torres, Juan Mauricio; Seligman, Thomas H
2011-01-01
We present a simple exactly solvable extension of of the Jaynes-Cummings model by adding dissipation. This is done such that the total number of excitations is conserved. The Liouville operator in the resulting master equation can be reduced to blocks of $4\\times 4$ matrices.
Parcell, L. A.; Mceachran, R. P.; Stauffer, A. D.
1990-01-01
The differential and total cross section for the excitation of the 3s1P10 and 3p1P1 states of neon by positron impact were calculated using a distorted-wave approximation. The results agree well with experimental conclusions.
Furrer, Albert; Waldmann, Oliver
2013-01-01
Magnetic clusters, i.e., assemblies of a finite number (between two or three and several hundred) of interacting spin centers which are magnetically decoupled from their environment, can be found in many materials ranging from inorganic compounds and magnetic molecules to artificial metal structures formed on surfaces and metalloproteins. Their magnetic excitation spectra are determined by the nature of the spin centers and of the magnetic interactions, and the particular arrangement of the mutual interaction paths between the spin centers. Small clusters of up to four magnetic ions are ideal model systems in which to examine the fundamental magnetic interactions, which are usually dominated by Heisenberg exchange, but often complemented by anisotropic and/or higher-order interactions. In large magnetic clusters, which may potentially deal with a dozen or more spin centers, there is the possibility of novel many-body quantum states and quantum phenomena. In this review the necessary theoretical concepts and experimental techniques to study the magnetic cluster excitations and the resulting characteristic magnetic properties are introduced, followed by examples of small clusters, demonstrating the enormous amount of detailed physical information that can be retrieved. The current understanding of the excitations and their physical interpretation in the molecular nanomagnets which represent large magnetic clusters is then presented, with a section devoted to the subclass of single-molecule magnets, distinguished by displaying quantum tunneling of the magnetization. Finally, there is a summary of some quantum many-body states which evolve in magnetic insulators characterized by built-in or field-induced magnetic clusters. The review concludes by addressing future perspectives in the field of magnetic cluster excitations.
Apparatus for photon excited catalysis
Saffren, M. M. (Inventor)
1977-01-01
An apparatus is described for increasing the yield of photonically excited gas phase reactions by extracting excess energy from unstable, excited species by contacting the species with the surface of a finely divided solid.
Gamma-decay study of sup 2 sup 1 Na and sup 2 sup 1 Ne, octupole bands in sup 2 sup 1 Ne
Thummerer, S; Kokalova, T; Bohlen, H G; Gebauer, B; Tumino, A; Massey, T N; Angelis, G D; Axiotis, M; Gadea, A; Kröll, T; Marginean, N; Napoli, D R; Poli, M; Ur, C; Bazzacco, D; Lenzi, S M; Alvarez, C R; Lunardi, S; Menegazzo, R; Bizzeti, P G; Bizzeti-Sona, A M
2003-01-01
The reactions sup 1 sup 6 O( sup 7 Li, 2n) and sup 1 sup 6 O( sup 7 Li, np) populating sup 2 sup 1 Na and sup 2 sup 1 Ne have been studied at E sub L = 27 MeV using the GASP gamma-detector array. The level scheme for sup 2 sup 1 Na and sup 2 sup 1 Ne has been extended to higher excitation energy. Spins and parities of the observed levels are assigned tentatively supporting the identification of opposite parity structures connected by strong dipole transitions. The structure of these bands is interpreted as based on a reflection asymmetric cluster structure.
Get excited: reappraising pre-performance anxiety as excitement.
Brooks, Alison Wood
2014-06-01
Individuals often feel anxious in anticipation of tasks such as speaking in public or meeting with a boss. I find that an overwhelming majority of people believe trying to calm down is the best way to cope with pre-performance anxiety. However, across several studies involving karaoke singing, public speaking, and math performance, I investigate an alternative strategy: reappraising anxiety as excitement. Compared with those who attempt to calm down, individuals who reappraise their anxious arousal as excitement feel more excited and perform better. Individuals can reappraise anxiety as excitement using minimal strategies such as self-talk (e.g., saying "I am excited" out loud) or simple messages (e.g., "get excited"), which lead them to feel more excited, adopt an opportunity mind-set (as opposed to a threat mind-set), and improve their subsequent performance. These findings suggest the importance of arousal congruency during the emotional reappraisal process.
Barranco Garcia, Javier; CERN. Geneva. ATS Department
2017-01-01
The Large Hadron Collider has shown with various experimental verifications that one of the main limitations to the collider performance and to a possible upgrade can come from the long-range beam-beam effects which will define the operational parameters (intensities and emittances) and machine set-up (crossing angles and the minimum beta function at the interaction points). The High Luminosity project aims at very high intensities and will therefore need much larger separations to keep the long range effects weak. In the past several studies of possible active compensators have been carried out and experimental studies are planned to explore such schemes in the LHC. In this note we show the feasibility of using octupole magnets to compensate the effects of long range beam-beam interactions by use of dynamical aperture simulations. A prove of principle of such a compensation scheme is shown for the HL-LHC optics. Preliminary studies for the LHC optics ATS and standard are also presented pointing to the import...
CINE: Comet INfrared Excitation
de Val-Borro, Miguel; Cordiner, Martin A.; Milam, Stefanie N.; Charnley, Steven B.
2017-08-01
CINE calculates infrared pumping efficiencies that can be applied to the most common molecules found in cometary comae such as water, hydrogen cyanide or methanol. One of the main mechanisms for molecular excitation in comets is the fluorescence by the solar radiation followed by radiative decay to the ground vibrational state. This command-line tool calculates the effective pumping rates for rotational levels in the ground vibrational state scaled by the heliocentric distance of the comet. Fluorescence coefficients are useful for modeling rotational emission lines observed in cometary spectra at sub-millimeter wavelengths. Combined with computational methods to solve the radiative transfer equations based, e.g., on the Monte Carlo algorithm, this model can retrieve production rates and rotational temperatures from the observed emission spectrum.
Neural Excitability and Singular Bifurcations.
De Maesschalck, Peter; Wechselberger, Martin
2015-12-01
We discuss the notion of excitability in 2D slow/fast neural models from a geometric singular perturbation theory point of view. We focus on the inherent singular nature of slow/fast neural models and define excitability via singular bifurcations. In particular, we show that type I excitability is associated with a novel singular Bogdanov-Takens/SNIC bifurcation while type II excitability is associated with a singular Andronov-Hopf bifurcation. In both cases, canards play an important role in the understanding of the unfolding of these singular bifurcation structures. We also explain the transition between the two excitability types and highlight all bifurcations involved, thus providing a complete analysis of excitability based on geometric singular perturbation theory.
Subsurface excitations in a metal
DEFF Research Database (Denmark)
Ray, M. P.; Lake, R. E.; Sosolik, C. E.;
2009-01-01
We investigate internal hot carrier excitations in a Au thin film bombarded by hyperthermal and low energy alkali and noble gas ions. Excitations within the thin film of a metal-oxide-semiconductor device are measured revealing that ions whose velocities fall below the classical threshold given...... by the free-electron model of a metal still excite hot carriers. Excellent agreement between these results and a nonadiabatic model that accounts for the time-varying ion-surface interaction indicates that the measured excitations are due to semilocalized electrons near the metal surface....
Energy Technology Data Exchange (ETDEWEB)
Lopez-Arrietea, M. G.; Solis, M. A.; De Llano, M. [Universidad Nacional Autonoma de Mexico, Mexico, D.F (Mexico)
2001-02-01
Excited cooper pairs formed in a many-fermion system are those with nonzero total center-of mass momentum (CMM). They are normally neglected in the standard Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity for being too few compared with zero CMM pairs. However, a Bose-Einstein condensation picture requires both zero and nonzero CMM pairs. Assuming a BCS model interaction between fermions we determine the populations for all CMM values of Cooper pairs by actually calculating the number of nonzero-CMM pairs relative to that of zero-CMM ones in both 2D and 3D. Although this ratio decreases rapidly with CMM, the number of Cooper pairs for any specific CMM less than the maximum (or breakup of the pair) momentum turns out to be typically larger than about 95% of those with zero-CMM at zero temperature T. Even at T {approx}100 K this fraction en 2D is still as large as about 70% for typical quasi-2D cuprate superconductor parameters. [Spanish] Los pares de cooper excitados formados en un sistema de muchos electrones, son aquellos con momentos de centro de masa (CMM) diferente de cero. Normalmente estos no son tomados en cuenta en la teoria estandar de la superconductividad de Bardeen-Cooper-Schrieffer (BCS) al suponer que su numero es muy pequeno comparados con los pares de centro de masa igual a cero. Sin embargo, un esquema de condensacion Bose-Einstein requiere de ambos pares, con CMM cero y diferente de cero. Asumiendo una interaccion modelo BCS entre los fermiones, determinamos la poblacion de pares cooper con cada uno de todos los posibles valores del CMM calculando el numero de pares con momentos de centro de masa diferente de cero relativo a los pares de CMM igual a cero, en 2D y 3D. Aunque esta razon decrece rapidamente con el CMM, el numero de pares de cooper para cualquier CMM especifico menor que el momento maximo (o rompimiento de par) es tipicamente mas grande que el 95% de aquellos con CMM cero. Aun a T {approx}100 K esta fraccion en 2D es
Uniform excitations in magnetic nanoparticles
DEFF Research Database (Denmark)
Mørup, Steen; Frandsen, Cathrine; Hansen, Mikkel Fougt
2010-01-01
We present a short review of the magnetic excitations in nanoparticles below the superparamagnetic blocking temperature. In this temperature regime, the magnetic dynamics in nanoparticles is dominated by uniform excitations, and this leads to a linear temperature dependence of the magnetization...... and the magnetic hyperfine field, in contrast to the Bloch T3/2 law in bulk materials. The temperature dependence of the average magnetization is conveniently studied by Mössbauer spectroscopy. The energy of the uniform excitations of magnetic nanoparticles can be studied by inelastic neutron scattering....
Uniform excitations in magnetic nanoparticles
DEFF Research Database (Denmark)
Mørup, Steen; Frandsen, Cathrine; Hansen, Mikkel Fougt
2010-01-01
We present a short review of the magnetic excitations in nanoparticles below the superparamagnetic blocking temperature. In this temperature regime, the magnetic dynamics in nanoparticles is dominated by uniform excitations, and this leads to a linear temperature dependence of the magnetization...... and the magnetic hyperfine field, in contrast to the Bloch T3/2 law in bulk materials. The temperature dependence of the average magnetization is conveniently studied by Mössbauer spectroscopy. The energy of the uniform excitations of magnetic nanoparticles can be studied by inelastic neutron scattering....
Effects of dark atom excitations
Cudell, Jean-René; Wallemacq, Quentin
2014-01-01
New stable quarks and charged leptons may exist and be hidden from detection, as they are bound by Coulomb interaction in neutral dark atoms of composite dark matter. This possibility leads to fundamentally new types of indirect effects related to the excitation of such dark atoms followed by their electromagnetic de-excitation. Stable -2 charged particles, bound to primordial helium in O-helium (OHe) atoms, represent the simplest model of dark atoms. Here we consider the structure of OHe atomic levels which is a necessary input for the indirect tests of such composite dark matter scenarios, and we give the spectrum of electromagnetic transitions from the levels excited in OHe collisions.
Coulomb excitations of monolayer germanene
Shih, Po-Hsin; Chiu, Yu-Huang; Wu, Jhao-Ying; Shyu, Feng-Lin; Lin, Ming-Fa
2017-01-01
The feature-rich electronic excitations of monolayer germanene lie in the significant spin-orbit coupling and the buckled structure. The collective and single-particle excitations are diversified by the magnitude and direction of transferred momentum, the Fermi energy and the gate voltage. There are four kinds of plasmon modes, according to the unique frequency- and momentum-dependent phase diagrams. They behave as two-dimensional acoustic modes at long wavelength. However, for the larger momenta, they might change into another kind of undamped plasmons, become the seriously suppressed modes in the heavy intraband e–h excitations, keep the same undamped plasmons, or decline and then vanish in the strong interband e–h excitations. Germanene, silicene and graphene are quite different from one another in the main features of the diverse plasmon modes. PMID:28091555
Resonance Radiation and Excited Atoms
Mitchell, Allan C. G.; Zemansky, Mark W.
2009-06-01
1. Introduction; 2. Physical and chemical effects connected with resonance radiation; 3. Absorption lines and measurements of the lifetime of the resonance state; 4. Collision processes involving excited atoms; 5. The polarization of resonance radiation; Appendix; Index.
Autowaves in moving excitable media
Directory of Open Access Journals (Sweden)
V.A.Davydov
2004-01-01
Full Text Available Within the framework of kinematic theory of autowaves we suggest a method for analytic description of stationary autowave structures appearing at the boundary between the moving and fixed excitable media. The front breakdown phenomenon is predicted for such structures. Autowave refraction and, particulary, one-side "total reflection" at the boundary is considered. The obtained analytical results are confirmed by computer simulations. Prospects of the proposed method for further studies of autowave dynamics in the moving excitable media are discussed.
Excitations of strange bottom baryons
Woloshyn, R M
2016-01-01
The ground state and first excited state masses of Omega(b) and Omega(bb) baryons are calculated in lattice QCD using dynamical 2+1 flavour gauge fields. A set of baryon operators employing different combinations of smeared quark fields was used in the framework of the variational method. Results for radial excitation energies were confirmed by carrying out a supplementary multiexponential fitting analysis. Comparison is made with quark model calculations.
Excitations of strange bottom baryons
Energy Technology Data Exchange (ETDEWEB)
Woloshyn, R.M. [TRIUMF, Vancouver, British Columbia (Canada)
2016-09-15
The ground-state and first-excited-state masses of Ω{sub b} and Ω{sub bb} baryons are calculated in lattice QCD using dynamical 2 + 1 flavour gauge fields. A set of baryon operators employing different combinations of smeared quark fields was used in the framework of the variational method. Results for radial excitation energies were confirmed by carrying out a supplementary multiexponential fitting analysis. Comparison is made with quark model calculations. (orig.)
2010-10-01
... 46 CFR 110.10-1). In particular, no static exciter may be used for excitation of an emergency generator unless it is provided with a permanent magnet or a residual-magnetism-type exciter that has...
Excitation with quantum light. I. Exciting a harmonic oscillator
Carreño, J. C. López; Laussy, F. P.
2016-12-01
We present a two-part study of the excitation of an optical target by quantum light. In this first part, we introduce the problematic and address the first case of interest, that of exciting the quantum harmonic oscillator, corresponding to, e.g., a single-mode passive cavity or a noninteracting bosonic field. We introduce a mapping of the Hilbert space that allows to chart usefully the accessible regions. We then consider the quantum excitation from single-photon sources in the form of a two-level system under various regimes of (classical) pumping: incoherent, coherent, and in the Mollow triplet regime. We close this first part with an overview of the material to be covered in the subsequent work.
Excited states rotational effects on the behavior of excited molecules
Lim, Edward C
2013-01-01
Excited States, Volume 7 is a collection of papers that discusses the excited states of molecules. The first paper reviews the rotational involvement in intra-molecular in vibrational redistribution. This paper analyzes the vibrational Hamiltonian as to its efficacy in detecting the manifestations of intra-molecular state-mixing in time-resolved and time-averaged spectroscopic measurements. The next paper examines the temporal behavior of intra-molecular vibration-rotation energy transfer (IVRET) and the effects of IVRET on collision, reaction, and the decomposition processes. This paper also
Sadomasochism, sexual excitement, and perversion.
Kernberg, O F
1991-01-01
Sadomasochism, an ingredient of infantile sexuality, is an essential part of normal sexual functioning and love relations, and of the very nature of sexual excitement. Sadomasochistic elements are also present in all sexual perversions. Sadomasochism starts out as the potential for erotic masochism in both sexes, and represents a very early capacity to link aggression with the libidinal elements of sexual excitement. Sexual excitement may be considered a basic affect that overcomes primitive splitting of love and hatred. Erotic desire is a more mature form of sexual excitement. Psychoanalytic exploration makes it possible to uncover the unconscious components of sexual excitement: wishes for symbiotic fusion and for aggressive penetration and intermingling; bisexual identifications; the desire to transgress oedipal prohibitions and the secretiveness of the primal scene, and to violate the boundaries of a teasing and withholding object. The relation between these wishes and the development of erotic idealization processes in both sexes is explored in the context of a critical review of the pertinent psychoanalytic literature.
Phase control of excitable systems
Energy Technology Data Exchange (ETDEWEB)
Zambrano, S; Seoane, J M; Marino, I P; Sanjuan, M A F [Nonlinear Dynamics and Chaos Group, Departamento de Fisica, Universidad Rey Juan Carlos, Tulipan s/n, 28933 Mostoles, Madrid (Spain); Euzzor, S; Meucci, R; Arecchi, F T [CNR-Istituto Nazionale di Ottica Applicata, Largo E. Fermi, 6 50125 Firenze (Italy)], E-mail: samuel.zambrano@urjc.es, E-mail: jesus.seoane@urjc.es, E-mail: ines.perez@urjc.es
2008-07-15
Here we study how to control the dynamics of excitable systems by using the phase control technique. Excitable systems are relevant in neuronal dynamics and therefore this method might have important applications. We use the periodically driven FitzHugh-Nagumo (FHN) model, which displays both spiking and non-spiking behaviours in chaotic or periodic regimes. The phase control technique consists of applying a harmonic perturbation with a suitable phase {phi} that we adjust in search of different behaviours of the FHN dynamics. We compare our numerical results with experimental measurements performed on an electronic circuit and find good agreement between them. This method might be useful for a better understanding of excitable systems and different phenomena in neuronal dynamics.
Dynamics of Elastic Excitable Media
Cartwright, J H E; Hernández-García, E; Piro, O; Cartwright, Julyan H. E.; Eguiluz, Victor M.; Hernandez-Garcia, Emilio; Piro, Oreste
1999-01-01
The Burridge-Knopoff model of earthquake faults with viscous friction is equivalent to a van der Pol-FitzHugh-Nagumo model for excitable media with elastic coupling. The lubricated creep-slip friction law we use in the Burridge-Knopoff model describes the frictional sliding dynamics of a range of real materials. Low-dimensional structures including synchronized oscillations and propagating fronts are dominant, in agreement with the results of laboratory friction experiments. Here we explore the dynamics of fronts in elastic excitable media.
Autoresonant Excitation of Antiproton Plasmas
Andresen, G. B.; Ashkezari, M. D.; Baquero-Ruiz, M.; Bertsche, W.; Bowe, P. D.; Butler, E.; Carpenter, P. T.; Cesar, C. L.; Chapman, S.; Charlton, M.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.; Hangst, J. S.; Hardy, W. N.; Hayden, M. E.; Humphries, A. J.; Hurt, J. L.; Hydomako, R.; Jonsell, S.; Madsen, N.; Menary, S.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Robicheaux, F.; Sarid, E.; Silveira, D. M.; So, C.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Wurtele, J. S.; Yamazaki, Y.
2011-01-01
We demonstrate controllable excitation of the center-of-mass longitudinal motion of a thermal antiproton plasma using a swept-frequency autoresonant drive. When the plasma is cold, dense, and highly collective in nature, we observe that the entire system behaves as a single-particle nonlinear oscillator, as predicted by a recent theory. In contrast, only a fraction of the antiprotons in a warm plasma can be similarly excited. Antihydrogen was produced and trapped by using this technique to drive antiprotons into a positron plasma, thereby initiating atomic recombination.
Chemical Physics Electrons and Excitations
Larsson, Sven
2012-01-01
A full understanding of modern chemistry is impossible without quantum theory. Since the advent of quantum mechanics in 1925, a number of chemical phenomena have been explained, such as electron transfer, excitation energy transfer, and other phenomena in photochemistry and photo-physics. Chemical bonds can now be accurately calculated with the help of a personal computer. Addressing students of theoretical and quantum chemistry and their counterparts in physics, Chemical Physics: Electrons and Excitations introduces chemical physics as a gateway to fields such as photo physics, solid-state ph
Autoresonant Excitation of Antiproton Plasmas
Andresen, Gorm B; Baquero-Ruiz, Marcelo; Bertsche, William; Bowe, Paul D; Butler, Eoin; Carpenter, P T; Cesar, Claudio L; Chapman, Steven; Charlton, Michael; Fajans, Joel; Friesen, Tim; Fujiwara, Makoto C; Gill, David R; Hangst, Jeffrey S; Hardy, Walter N; Hayden, Michael E; Humphries, Andrew J; Hurt, J L; Hydomako, Richard; Jonsell, Svante; Madsen, Niels; Menary, Scott; Nolan, Paul; Olchanski, Konstantin; Olin, Art; Povilus, Alexander; Pusa, Petteri; Robicheaux, Francis; Sarid, Eli; Silveira, Daniel M; So, Chukman; Storey, James W; Thompson, Robert I; van der Werf, Dirk P; Wurtele, Jonathan S; Yamazaki, Yasunori
2011-01-01
We demonstrate controllable excitation of the center-of-mass longitudinal motion of a thermal antiproton plasma using a swept-frequency autoresonant drive. When the plasma is cold, dense, and highly collective in nature, we observe that the entire system behaves as a single-particle nonlinear oscillator, as predicted by a recent theory. In contrast, only a fraction of the antiprotons in a warm plasma can be similarly excited. Antihydrogen was produced and trapped by using this technique to drive antiprotons into a positron plasma, thereby initiating atomic recombination.
Probabilistic excitation of plasma transitions
Energy Technology Data Exchange (ETDEWEB)
Itoh, Sanae; Toda, Shinichiro; Yagi, Masatoshi [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics; Itoh, Kimitaka; Fukuyama, Atsushi
1998-12-01
Statistical property of an excitation of plasma transition is analyzed, which takes place in a strongly turbulent state. Transition characteristics which have been studied in a deterministic picture are re-examined. Model equations of transition, with a hysteresis nature in flux-gradient relation in the presence of strong self-noise, are solved and the dynamics of plasma gradient and turbulent-driven flux is studied. The excitation probability is shown to be fairly large well below the conventional critical condition. Probability distribution function, as a function of the gradient, for an onset of the transition is obtained both for power law noise. (author)
Calibrated Noncontact Exciters for Optical Modal Analysis
Directory of Open Access Journals (Sweden)
Henrik O. Saldner
1996-01-01
Full Text Available Two types of exciters were investigated experimentally One of the exciters uses a small permanent magnet fastened on the object. The force is introduced by the change in the electromagnetic field from a coil via an air gap. The second exciter is an eddy-current electromagnet one. The amplitude of the forces from these exciters are calibrated by using dynamic reciprocity in conjunction with electronic holography. These forces strongly depend upon the distance between the exciter and the object.
Skyrmion Excitations in Planar Ferromagnets
Institute of Scientific and Technical Information of China (English)
WANG Ji-Biao; REN Ji-Rong; LI Ran
2009-01-01
By making use of the (φ)-mapping topological current theory and the decomposition of gauge potential theory, we investigate the (2+1)-dimensional skyrmion excitations in ferromagnets. We also discuss the branch processes of these skyrmions and the generation and annihilation of skyrmion-antiskyrmion pairs.
Predictions for Excited Strange Baryons
Energy Technology Data Exchange (ETDEWEB)
Fernando, Ishara P.; Goity, Jose L. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2016-04-01
An assessment is made of predictions for excited hyperon masses which follow from flavor symmetry and consistency with a 1/N c expansion of QCD. Such predictions are based on presently established baryonic resonances. Low lying hyperon resonances which do not seem to fit into the proposed scheme are discussed.
Band excitation Kelvin probe force microscopy utilizing photothermal excitation
Energy Technology Data Exchange (ETDEWEB)
Collins, Liam, E-mail: Liam.Collins@ucdconnect.ie, E-mail: liq1@ORNL.gov; Rodriguez, Brian J. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4 (Ireland); Jesse, Stephen; Balke, Nina; Kalinin, Sergei; Li, Qian, E-mail: Liam.Collins@ucdconnect.ie, E-mail: liq1@ORNL.gov [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
2015-03-09
A multifrequency open loop Kelvin probe force microscopy (KPFM) approach utilizing photothermal as opposed to electrical excitation is developed. Photothermal band excitation (PthBE)-KPFM is implemented here in a grid mode on a model test sample comprising a metal-insulator junction with local charge-patterned regions. Unlike the previously described open loop BE-KPFM, which relies on capacitive actuation of the cantilever, photothermal actuation is shown to be highly sensitive to the electrostatic force gradient even at biases close to the contact potential difference (CPD). PthBE-KPFM is further shown to provide a more localized measurement of true CPD in comparison to the gold standard ambient KPFM approach, amplitude modulated KPFM. Finally, PthBE-KPFM data contain information relating to local dielectric properties and electronic dissipation between tip and sample unattainable using conventional single frequency KPFM approaches.
Energy Technology Data Exchange (ETDEWEB)
Dorner, B. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)
1996-12-31
A short introduction to instrumental resolution is followed by a discussion of visibilities of phonon modes due to their eigenvectors. High precision phonon dispersion curves in GaAs are presented together with `ab initio` calculations. Al{sub 2}O{sub 3} is taken as an example of selected visibility due to group theory. By careful determination of phonon intensities eigenvectors can be determined, such as in Silicon and Diamond. The investigation of magnon modes is shown for the garnet Fe{sub 2}Ca{sub 3}(GeO{sub 4}){sub 3}, where also a quantum gap due to zero point spin fluctuations was observed. The study of the splitting of excitons in CsFeCl{sub 3} in an applied magnetic field demonstrates the possibilities of neutron polarisation analysis, which made it possible to observe a mode crossing. An outlook to inelastic X-ray scattering with very high energy resolution of synchrotron radiation is given with the examples of phonons in Beryllium and in water. (author) 19 figs., 36 refs.
Backreaction of excitations on a vortex
Arodz, H; Arodz, Henryk; Hadasz, Leszek
1997-01-01
Excitations of a vortex are usually considered in a linear approximation neglecting their backreaction on the vortex. In the present paper we investigate backreaction of Proca type excitations on a straightlinear vortex in the Abelian Higgs model. We propose exact Ansatz for fields of the excited vortex. From initial set of six nonlinear field equations we obtain (in a limit of weak excitations) two linear wave equations for the backreaction corrections. Their approximate solutions are found in the cases of plane wave and wave packet type excitations. We find that the excited vortex radiates vector field and that the Higgs field has a very broad oscillating component.
Mean excitation energies for molecular ions
DEFF Research Database (Denmark)
Jensen, Phillip W. K.; Sauer, Stephan P. A.; Oddershede, Jens;
2017-01-01
The essential material constant that determines the bulk of the stopping power of high energy projectiles, the mean excitation energy, is calculated for a range of smaller molecular ions using the RPA method. It is demonstrated that the mean excitation energy of both molecules and atoms increase...... with ionic charge. However, while the mean excitation energies of atoms also increase with atomic number, the opposite is the case for mean excitation energies for molecules and molecular ions. The origin of these effects is explained by considering the spectral representation of the excited state...... contributing to the mean excitation energy....
Mean excitation energies for molecular ions
Jensen, Phillip W. K.; Sauer, Stephan P. A.; Oddershede, Jens; Sabin, John R.
2017-03-01
The essential material constant that determines the bulk of the stopping power of high energy projectiles, the mean excitation energy, is calculated for a range of smaller molecular ions using the RPA method. It is demonstrated that the mean excitation energy of both molecules and atoms increase with ionic charge. However, while the mean excitation energies of atoms also increase with atomic number, the opposite is the case for mean excitation energies for molecules and molecular ions. The origin of these effects is explained by considering the spectral representation of the excited state contributing to the mean excitation energy.
Mean excitation energies for molecular ions
Energy Technology Data Exchange (ETDEWEB)
Jensen, Phillip W.K.; Sauer, Stephan P.A. [Department of Chemistry, University of Copenhagen, Copenhagen (Denmark); Oddershede, Jens [Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense (Denmark); Quantum Theory Project, Departments of Physics and Chemistry, University of Florida, Gainesville, FL (United States); Sabin, John R., E-mail: sabin@qtp.ufl.edu [Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense (Denmark); Quantum Theory Project, Departments of Physics and Chemistry, University of Florida, Gainesville, FL (United States)
2017-03-01
The essential material constant that determines the bulk of the stopping power of high energy projectiles, the mean excitation energy, is calculated for a range of smaller molecular ions using the RPA method. It is demonstrated that the mean excitation energy of both molecules and atoms increase with ionic charge. However, while the mean excitation energies of atoms also increase with atomic number, the opposite is the case for mean excitation energies for molecules and molecular ions. The origin of these effects is explained by considering the spectral representation of the excited state contributing to the mean excitation energy.
Receiver-exciter controller design
Jansma, P. A.
1982-01-01
A description of the general design of both the block 3 and block 4 receiver-exciter controllers for the Deep Space Network (DSN) Mark IV-A System is presented along with the design approach. The controllers are designed to enable the receiver-exciter subsystem (RCV) to be configured, calibrated, initialized and operated from a central location via high level instructions. The RECs are designed to be operated under the control of the DMC subsystem. The instructions are in the form of standard subsystem blocks (SSBs) received via the local area network (LAN). The centralized control provided by RECs and other DSCC controllers in Mark IV-A is intended to reduce DSN operations costs from the Mark III era.
Light baryons and their excitations
Eichmann, Gernot; Fischer, Christian S.; Sanchis-Alepuz, Hèlios
2016-11-01
We study ground states and excitations of light octet and decuplet baryons within the framework of Dyson-Schwinger and Faddeev equations. We improve upon similar approaches by explicitly taking into account the momentum-dependent dynamics of the quark-gluon interaction that leads to dynamical chiral symmetry breaking. We perform calculations in both the three-body Faddeev framework and the quark-diquark approximation in order to assess the impact of the latter on the spectrum. Our results indicate that both approaches agree well with each other. The resulting spectra furthermore agree one-to-one with experiment, provided well-known deficiencies of the rainbow-ladder approximation are compensated for. We also discuss the mass evolution of the Roper and the excited Δ with varying pion mass and analyze the internal structure in terms of their partial wave decompositions.
Synaptic control of motoneuronal excitability
DEFF Research Database (Denmark)
Rekling, J C; Funk, G D; Bayliss, D A
2000-01-01
Movement, the fundamental component of behavior and the principal extrinsic action of the brain, is produced when skeletal muscles contract and relax in response to patterns of action potentials generated by motoneurons. The processes that determine the firing behavior of motoneurons are therefore......, and membrane properties, both passive and active. We then describe the general anatomical organization of synaptic input to motoneurons, followed by a description of the major transmitter systems that affect motoneuronal excitability, including ligands, receptor distribution, pre- and postsynaptic actions...... and norepinephrine, and neuropeptides, as well as the glutamate and GABA acting at metabotropic receptors, modulate motoneuronal excitability through pre- and postsynaptic actions. Acting principally via second messenger systems, their actions converge on common effectors, e.g., leak K(+) current, cationic inward...
Uniform magnetic excitations in nanoparticles
DEFF Research Database (Denmark)
Mørup, Steen; Hansen, Britt Rosendahl
2005-01-01
We have used a spin-wave model to calculate the temperature dependence of the (sublattice) magnetization of magnetic nanoparticles. The uniform precession mode, corresponding to a spin wave with wave vector q=0, is predominant in nanoparticles and gives rise to an approximately linear temperature...... dependence of the (sublattice) magnetization well below the superparamagnetic blocking temperature for both ferro-, ferri-, and antiferromagnetic particles. This is in accordance with the results of a classical model for collective magnetic excitations in nanoparticles. In nanoparticles of antiferromagnetic...... materials, quantum effects give rise to a small deviation from the linear temperature dependence of the (sublattice) magnetization at very low temperatures. The complex nature of the excited precession states of nanoparticles of antiferromagnetic materials, with deviations from antiparallel orientation...
International Meeting: Excited QCD 2014
Giacosa, Francesco; Malek, Magdalena; Marinkovic, Marina; Parganlija, Denis
2014-01-01
Excited QCD 2014 will take place on the beautiful Bjelasnica mountain located in the vicinity of the Bosnian capital Sarajevo. Bjelasnica was a venue of the XIV Winter Olympic Games and it is situated only 30 kilometers from Sarajevo International Airport. The workshop program will start on February 2 and finish on February 8, 2014, with scientific lectures taking place from February 3 to 7. Workshop participants will be accomodated in Hotel Marsal, only couple of minutes by foot from the Olympic ski slopes. ABOUT THE WORKSHOP This edition is the sixth in a series of workshops that were previously organised in Poland, Slovakia, France and Portugal. Following the succesful meeting in 2013, the Workshop is returning to Sarajevo Olympic mountains in 2014, exactly thirty years after the Games. The workshop covers diverse aspects of QCD: (i) QCD at low energies: excited hadrons, glueballs, multiquarks. (ii) QCD at high temperatures and large densities: heavy-ion collisions, jets, diffraction, hadronisation, quark-...
Excitation energies from ensemble DFT
Borgoo, Alex; Teale, Andy M.; Helgaker, Trygve
2015-12-01
We study the evaluation of the Gross-Oliveira-Kohn expression for excitation energies E1-E0=ɛ1-ɛ0+∂E/xc,w[ρ] ∂w | ρ =ρ0. This expression gives the difference between an excitation energy E1 - E0 and the corresponding Kohn-Sham orbital energy difference ɛ1 - ɛ0 as a partial derivative of the exchange-correlation energy of an ensemble of states Exc,w[ρ]. Through Lieb maximisation, on input full-CI density functions, the exchange-correlation energy is evaluated accurately and the partial derivative is evaluated numerically using finite difference. The equality is studied numerically for different geometries of the H2 molecule and different ensemble weights. We explore the adiabatic connection for the ensemble exchange-correlation energy. The latter may prove useful when modelling the unknown weight dependence of the exchange-correlation energy.
Excitation rates of heavy quarks
Energy Technology Data Exchange (ETDEWEB)
Canal, C.A.G.; Santangelo, E.M.; Ducati, M.B.G.
1985-06-01
We obtain the production rates for c, b, and t quarks in deep-inelastic neutrino- (antineutrino-) nucleon interactions, in the standard six-quark model with left-handed couplings. The results are obtained with the most recent mixing parameters and we include a comparison between quark parametrizations. The excitations are calculated separately for each flavor, allowing the understanding of the role of threshold effects when considered through different rescaling variables.
Diriken, J.; Stefanescu, I.; Balabanski, D.; Blasi, N.; Blazhev, A.; Bree, N.; Cederkaell, J.; Cocolios, T. E.; Davinson, T.; Eberth, J.; Ekstrom, A.; Fedorov, D. V.; Fedosseev, V. N.; Fraile, L. M.; Franchoo, S.; Georgiev, G.; Gladnishki, K.; Huyse, M.; Ivanov, O. V.; Ivanov, V. S.; Iwanicki, J.; Jolie, J.; Konstantinopoulos, T.; Kroell, Th.; Kruecken, R.; Koester, U.; Lagoyannis, A.; Lo Bianco, G.; Maierbeck, P.; Marsh, B. A.; Napiorkowski, P.; Patronis, N.; Pauwels, D.; Reiter, P.; Seliverstov, M.; Sletten, G.; Van de Walle, J.; Van Duppen, P.; Voulot, D.; Walters, W. B.; Warr, N.; Wenander, F.; Wrzosek, K.
2010-01-01
The B(E2; I-i -> I-f) values for transitions in Ga-71(31)40 and Ga-73(31)42 were deduced from a Coulomb excitation experiment at the safe energy of 2.95 MeV/nucleon using post-accelerated beams of Ga-71,Ga-73 at the REX-ISOLDE on-line isotope mass separator facility. The emitted gamma rays were dete
A semiconductor laser excitation circuit
Energy Technology Data Exchange (ETDEWEB)
Kaadzunari, O.; Masaty, K.
1984-03-27
A semiconductor laser excitation circuit is patented that is designed for operation in a pulsed mode with a high pulse repetition frequency. This circuit includes, in addition to a semiconductor laser, a high speed photodetector, a reference voltage source, a comparator, and a pulse oscillator and modulator. If the circuit is built using standard silicon integrated circuits, its speed amounts to several hundred megahertz, if it is constructed using gallium arsenide integrated circuits, its speed is several gigahertz.
Reflex excitability regulates prepulse inhibition.
Schicatano, E J; Peshori, K R; Gopalaswamy, R; Sahay, E; Evinger, C
2000-06-01
Presentation of a weak stimulus, a prepulse, before a reflex-evoking stimulus decreases the amplitude of the reflex response relative to reflex amplitude evoked without a preceding prepulse. For example, presenting a brief tone before a trigeminal blink-eliciting stimulus significantly reduces reflex blink amplitude. A common explanation of such data are that sensory processing of the prepulse modifies reflex circuit behavior. The current study investigates the converse hypothesis that the intrinsic characteristics of the reflex circuit rather than prepulse processing determine prepulse modification of trigeminal and acoustic reflex blinks. Unilateral lesions of substantia nigra pars compacta neurons created rats with hyperexcitable trigeminal reflex blinks but normally excitable acoustic reflex blinks. In control rats, presentation of a prepulse reduced the amplitude of both trigeminal and acoustic reflex blinks. In 6-OHDA-lesioned rats, however, the same acoustic prepulse facilitated trigeminal reflex blinks but inhibited acoustic reflex blinks. The magnitude of prepulse modification correlated with reflex excitability. Humans exhibited the same pattern of prepulse modification. An acoustic prepulse facilitated the trigeminal reflex blinks of subjects with hyperexcitable trigeminal reflex blinks caused by Parkinson's disease. The same prepulse inhibited trigeminal reflex blinks of age-matched control subjects. Prepulse modification also correlated with trigeminal reflex blink excitability. These data show that reflex modification by a prepulse reflects the intrinsic characteristics of the reflex circuit rather than an external adjustment of the reflex circuit by the prepulse.
Entanglement entropy of electronic excitations.
Plasser, Felix
2016-05-21
A new perspective into correlation effects in electronically excited states is provided through quantum information theory. The entanglement between the electron and hole quasiparticles is examined, and it is shown that the related entanglement entropy can be computed from the eigenvalue spectrum of the well-known natural transition orbital (NTO) decomposition. Non-vanishing entanglement is obtained whenever more than one NTO pair is involved, i.e., in the case of a multiconfigurational or collective excitation. An important implication is that in the case of entanglement it is not possible to gain a complete description of the state character from the orbitals alone, but more specific analysis methods are required to decode the mutual information between the electron and hole. Moreover, the newly introduced number of entangled states is an important property by itself giving information about excitonic structure. The utility of the formalism is illustrated in the cases of the excited states of two interacting ethylene molecules, the conjugated polymer para-phenylene vinylene, and the naphthalene molecule.
Channelopathies of skeletal muscle excitability
Cannon, Stephen C.
2016-01-01
Familial disorders of skeletal muscle excitability were initially described early in the last century and are now known to be caused by mutations of voltage-gated ion channels. The clinical manifestations are often striking, with an inability to relax after voluntary contraction (myotonia) or transient attacks of severe weakness (periodic paralysis). An essential feature of these disorders is fluctuation of symptoms that are strongly impacted by environmental triggers such as exercise, temperature, or serum K+ levels. These phenomena have intrigued physiologists for decades, and in the past 25 years the molecular lesions underlying these disorders have been identified and mechanistic studies are providing insights for therapeutic strategies of disease modification. These familial disorders of muscle fiber excitability are “channelopathies” caused by mutations of a chloride channel (ClC-1), sodium channel (NaV1.4), calcium channel (CaV1.1) and several potassium channels (Kir2.1, Kir2.6, Kir3.4). This review provides a synthesis of the mechanistic connections between functional defects of mutant ion channels, their impact on muscle excitability, how these changes cause clinical phenotypes, and approaches toward therapeutics. PMID:25880512
Channelopathies of skeletal muscle excitability.
Cannon, Stephen C
2015-04-01
Familial disorders of skeletal muscle excitability were initially described early in the last century and are now known to be caused by mutations of voltage-gated ion channels. The clinical manifestations are often striking, with an inability to relax after voluntary contraction (myotonia) or transient attacks of severe weakness (periodic paralysis). An essential feature of these disorders is fluctuation of symptoms that are strongly impacted by environmental triggers such as exercise, temperature, or serum K(+) levels. These phenomena have intrigued physiologists for decades, and in the past 25 years the molecular lesions underlying these disorders have been identified and mechanistic studies are providing insights for therapeutic strategies of disease modification. These familial disorders of muscle fiber excitability are "channelopathies" caused by mutations of a chloride channel (ClC-1), sodium channel (NaV1.4), calcium channel (CaV1.1), and several potassium channels (Kir2.1, Kir2.6, and Kir3.4). This review provides a synthesis of the mechanistic connections between functional defects of mutant ion channels, their impact on muscle excitability, how these changes cause clinical phenotypes, and approaches toward therapeutics. © 2015 American Physiological Society.
Excitation system testing in HPP 'Uvac'
Directory of Open Access Journals (Sweden)
Milojčić Nemanja
2011-01-01
Full Text Available The excitation system of hydro unit in HPP 'Uvac' and results of testings of excitation system performed for achieving of unit's mathematical model are presented in this paper. Description of excitation system equipment, parameters of regulators and results obtained after testings are presented. The presented results showed that the regulators are properly adjusted and that the excitation system is completely functional and reliable.
Control of excitation in the fluorescence microscope.
Lea, D J; Ward, D J
1979-01-01
In fluorescence microscopy image brightness and contrast and the rate of fading depend upon the intensity of illumination of the specimen. An iris diaphragm or neutral density filters may be used to reduce fluorescence excitation. Also the excitation bandwidth may be varied by using a broad band exciter filter with a set of interchangeable yellow glass filters at the lamphouse.
Giant Magnetostrictive Material Exciter for Panel Loudspeaker
Institute of Scientific and Technical Information of China (English)
WANG Rui; ZHANG Yong-fa
2008-01-01
The exciter component in a panel loudspeaker has a profound effect on the overall performance of the system.The equivalent circuit analysis of the combination of giant magnetostrictive material exciter and distributed mode panel is introduced and how exciter parameters influence panel lffudspeaker's performance is discussed.NumericaI predictions are given in order to show how these influences are manifested.
New Modes of Nuclear Excitations
Tsoneva, Nadia
2014-01-01
We present a theoretical approach based on density functional theory supplemented by a microscopic multi-phonon model which is applied for investigations of pygmy resonances and other excitations of different multipolarities in stable and exotic nuclei. The possible relation of low-energy modes to the properties of neutron or proton skins is systematically studied in isotonic and isotopic chains. The fine structure of nuclear electric and magnetic response functions is analyzed and compared to experimental data. Their relevance to nuclear astrophysics is discussed.
Electromagnetic Excitation of Nucleon Resonances
Tiator, L; Kamalov, S S; Vanderhaeghen, M
2011-01-01
Recent progress on the extraction of electromagnetic properties of nucleon resonance excitation through pion photo- and electroproduction is reviewed. Cross section data measured at MAMI, ELSA, and CEBAF are analyzed and compared to the analysis of other groups. On this basis, we derive longitudinal and transverse transition form factors for most of the four-star nucleon resonances. Furthermore, we discuss how the transition form factors can be used to obtain empirical transverse charge densities. Contour plots of the thus derived densities are shown for the Delta, Roper, S11, and D13 nucleon resonances.
Quasiparticle excitations in frustrated antiferromagnets
Energy Technology Data Exchange (ETDEWEB)
Trumper, Adolfo E. [Instituto de Fisica Rosario (CONICET) Universidad Nacional de Rosario, Boulevard 27 de Febrero 210 bis, 2000 Rosario (Argentina)]. E-mail: trumper@ifir.edu.ar; Gazza, Claudio J. [Instituto de Fisica Rosario (CONICET) Universidad Nacional de Rosario, Boulevard 27 de Febrero 210 bis, 2000 Rosario (Argentina); Manuel, Luis O. [Instituto de Fisica Rosario (CONICET) Universidad Nacional de Rosario, Boulevard 27 de Febrero 210 bis, 2000 Rosario (Argentina)]. E-mail: manuel@ifir.edu.ar
2004-12-31
We have computed the quasiparticle wave function corresponding to a hole injected in a triangular antiferromagnet. We have taken into account multi-magnon contributions within the self-consistent Born approximation. We have found qualitative differences, under sign reversal of the integral transfer t, regarding the multi-magnon components and the own existence of the quasiparticle excitations. Such differences are due to the subtle interplay between magnon-assisted and free hopping mechanisms. We conclude that the conventional quasiparticle picture can be broken by geometrical frustration without invoking spin liquid phases.
Quantum kink and its excitations
Rajantie, Arttu
2009-01-01
We show how detailed properties of a kink in quantum field theory can be extracted from field correlation functions. This makes it possible to study quantum kinks in a fully non-perturbative way using Monte Carlo simulations. We demonstrate this by calculating the kink mass as well as the spectrum and approximate wave functions of its excitations. This way of measuring the kink mass has clear advantages over the existing approaches based on creation and annihilation operators or the kink free energy. Our methods are straightforward to generalise to more realistic theories and other defect types.
High Frequency Chandler Wobble Excitation
Seitz, F.; Stuck, J.; Thomas, M.
2003-04-01
Variations of Earth rotation on sub-daily to secular timescales are caused by mass redistributions in the Earth system as a consequence of geophysical processes and gravitational influences. Forced oscillations of polar motion are superposed by free oscillations of the Earth, i.e. the Chandler wobble and the free core nutation. In order to study the interactions between externally induced polar motion and the Earth's free oscillations, a non-linear gyroscopic model has been developed. In most of the former investigations on polar motion, the Chandler wobble is introduced as a damped oscillation with predetermined frequency and amplitude. However, as the effect of rotational deformation is a backcoupling mechanism of polar motion on the Earth's rotational dynamics, both period and amplitude of the Chandler wobble are time-dependent when regarding additional excitations from, e.g., atmospheric or oceanic mass redistributions. The gyroscopic model is free of any explicit information concerning amplitude, phase, and period of free oscillations. The characteristics of the Earth's free oscillation is reproduced by the model from rheological and geometrical parameters and rotational deformation is taken into account. This enables to study the time variable Chandler oscillation when the gyro is forced with atmospheric and oceanic angular momentum from the global atmospheric ECHAM3-T21 general circulation model together with the ocean model for circulation and tides OMCT driven by ECHAM including surface pressure. Besides, mass redistributions in the Earth's body due to gravitational and loading deformations are regarded and external torques exerted by Moon and Sun are considered. The numerical results of the gyro are significantly related with the geodetically observed time series of polar motion published by the IERS. It is shown that the consistent excitation is capable to counteract the damping and thus to maintain the Chandler amplitude. Spectral analyses of the ECHAM
Excited state Intramolecular Proton Transfer in Anthralin
DEFF Research Database (Denmark)
Møller, Søren; Andersen, Kristine B.; Spanget-Larsen, Jens
1998-01-01
Quantum chemical calculations performed on anthralin (1,8-dihydroxy-9(10H)-anthracenone) predict the possibility of an excited-state intramolecular proton transfer process. Fluorescence excitation and emission spectra of the compound dissolved in n-hexane at ambient temperature results in an unus......Quantum chemical calculations performed on anthralin (1,8-dihydroxy-9(10H)-anthracenone) predict the possibility of an excited-state intramolecular proton transfer process. Fluorescence excitation and emission spectra of the compound dissolved in n-hexane at ambient temperature results......, associated with an excited-state intramolecular proton transfer process....
Electron impact excitations of S2 molecules
Tashiro, Motomichi
2007-01-01
Low-energy electron impact excitations of S_2 molecules are studied using the fixed-bond R-matrix method based on state-averaged complete active space SCF orbitals. Integral cross sections are calculated for elastic electron collision as well as impact excitation of the 7 lowest excited electronic states. Also, differential cross sections are obtained for elastic collision and excitation of the a^1 Delta_g, b^1 Sigma_g^+ and B^3 Sigma_u^- states. The integrated cross section of optically allowed excitation of the B^3 Sigma_u^- state agrees reasonably well with the available theoretical result.
Inwardly rotating spirals in nonuniform excitable media.
Gao, Xiang; Feng, Xia; Cai, Mei-chun; Li, Bing-wei; Ying, He-ping; Zhang, Hong
2012-01-01
Inwardly rotating spirals (IRSs) have attracted great attention since their observation in an oscillatory reaction-diffusion system. However, IRSs have not yet been reported in planar excitable media. In the present work we investigate rotating waves in a nonuniform excitable medium, consisting of an inner disk part surrounded by an outer ring part with different excitabilities, by numerical simulations of a simple FitzHugh-Nagumo model. Depending on the excitability of the medium as well as the inhomogeneity, we find the occurrence of IRSs, of which the excitation propagates inwardly to the geometrical spiral tip.
Energy Technology Data Exchange (ETDEWEB)
Sheikh Obeid, Abdulrahman
2014-11-01
In the framework of this thesis electron scattering experiments on low-energy excitations of {sup 92}Zr and {sup 94}Zr were performed at the S-DALINAC in a momentum transfer range q=0.3-0.6 fm{sup -1}. The nature of one-phonon symmetric and mixed-symmetric 2{sup +} and 3{sup -} states of {sup 92}Zr was investigated by comparison with predictions of the quasi-particle phonon model (QPM). Theoretical (e,e') cross sections have been calculated within the distorted wave Born approximation (DWBA) to account for Coulomb distortion effects. The reduced strengths of the one-quadrupole phonon states and the one-octupole phonon state have been extracted. The similarity of the momentum-transfer dependence of the form factors between the 2{sup +} states supports the one-phonon nature of the 2{sup +}{sub 2} state of {sup 92}Zr. A new method based on the Plane Wave Born Approximation (PWBA) for a model-independent determination of the ratio of the E2 transition strengths of fully symmetric (FSS) and mixed-symmetry (MSS) one-phonon excitations of heavy vibrational nuclei is introduced. Due to the sensitivity of electron scattering to charge distributions, the charge transition-radii difference can be determined. The basic assumptions (independence from the ratio of Coulomb corrections and from absolute values of transition radii) are tested within the Tassie model, which makes no specific assumptions about the structure of the states other than collectivity. It is shown that a PWBA analysis of the form factors, which usually fails for heavy nuclei, can nevertheless be applied in a relative analysis. This is a new promising approach to determine the ground state transition strength of the 2{sup +} MSS of vibrational nuclei with a precision limited only by the experimental information about the B(E2;2{sup +}{sub 1}→0{sup +}{sub 1}) strength. The PWBA approach furthermore provides information about differences of the proton transition radii of the respective states
Analysis on the Pressure Fluctuation Law of a Hydraulic Exciting System with a Wave-exciter
Institute of Scientific and Technical Information of China (English)
WEI Xiu-ye; KOU Zi-ming; LU Zi-rong
2011-01-01
A hydraulic exciting system with a wave exciter has been constructed in order to study the hydraulic vibra- tion law. The system consists of an oil source, wave-exciter and oil cylinder, and is controlled by a wave-exciter. The working principle of the hydraulic exciting system and wave exciter has been analyzed, and its excitation process has been illustrated. The law of every pipe＇s pressure fluctuation of the system is obtained by experiment. The theo- retical analysis and experimental data prove that the pipeline pressure periodically changes and the pipeline pressure fluctuation frequency is independently controlled by the excitation frequency of the wave-exciter. Every pipelinc＇s pressure wave is produced by system flow fluctuation and water hammer coupling. The pressure fluctuation rules of the system provide a theoretical basis for the study of the associated liberation system.
Excited Baryons in Holographic QCD
Energy Technology Data Exchange (ETDEWEB)
de Teramond, Guy F.; /Costa Rica U.; Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins
2011-11-08
The light-front holographic QCD approach is used to describe baryon spectroscopy and the systematics of nucleon transition form factors. Baryon spectroscopy and the excitation dynamics of nucleon resonances encoded in the nucleon transition form factors can provide fundamental insight into the strong-coupling dynamics of QCD. The transition from the hard-scattering perturbative domain to the non-perturbative region is sensitive to the detailed dynamics of confined quarks and gluons. Computations of such phenomena from first principles in QCD are clearly very challenging. The most successful theoretical approach thus far has been to quantize QCD on discrete lattices in Euclidean space-time; however, dynamical observables in Minkowski space-time, such as the time-like hadronic form factors are not amenable to Euclidean numerical lattice computations.
Some Excitation Functions of Bismuth
Energy Technology Data Exchange (ETDEWEB)
Kelly, E.L.; Segre, E.
1948-10-10
Excitation functions have been measured, using a 38-Mev alpha-beam and a 19-Mev deuteron beam for the following reactions: Bi({alpha},2n)At{sup 211}, Bi({alpha},3n)At{sup 210}, Bi(d,p)Ra E, Bi(d,n)Po{sup 210}, and Bi(d,3n)Po{sup 209}. The results are summarized in Figs. 4 and 5 and Tables I and II. A new isotope of astatine, At{sup 210}, has been identified; this isotope has a half life of 8.3 hr., decaying by K-capture to Po{sup 210} with the emission of a 1.0-Mev gamma-ray and a few conversion electrons.
Accelerating structure with linear excitation
Energy Technology Data Exchange (ETDEWEB)
Fischer, J.; Srinivasan-Rao, T.
1988-03-01
The switched power linac (SPL) structures require a ring-shaped laser beam pulse of uniform intensity to avoid transverse field components of the accelerating field at the center. In order to also utilize the reflection of the outgoing EM wave, the switching element has to be very close to the outer edge of the structure to ensure nearly synchronous superposition at the beam hole with the original inward going wave. It is sometimes easier to produce linear (flat) laser beams, e.g., from powerful excimer lasers which have beams of rectangular cross section. Such flat beams could be used to excite linear photocathode switches or be used to produce flat electron beam pulses in electron sources. In this paper, an accelerator structure is proposed which may be considered a variant of the SPL disk structure, but could be used with linear beams. The structure utilizes a double parabolic horn. 8 refs., 9 figs.
Relaxation of the electron spin in quantum dots via one- and two-phonon processes
Energy Technology Data Exchange (ETDEWEB)
Calero, C. [Department of Physics and Astronomy, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY 10468-1589 (United States)]. E-mail: carlos.calero-borrallo@lehman.cuny.edu; Chudnovsky, E.M. [Department of Physics and Astronomy, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY 10468-1589 (United States); Garanin, D.A. [Department of Physics and Astronomy, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY 10468-1589 (United States)
2007-09-15
We have studied direct and Raman processes of the decay of electron spin states in a quantum dot via radiation of phonons corresponding to elastic twists. Universal dependence of the spin relaxation rate on the strength and direction of the magnetic field has been obtained in terms of the electron gyromagnetic tensor and macroscopic elastic constants of the solid.
Statistical dynamo theory: Mode excitation.
Hoyng, P
2009-04-01
We compute statistical properties of the lowest-order multipole coefficients of the magnetic field generated by a dynamo of arbitrary shape. To this end we expand the field in a complete biorthogonal set of base functions, viz. B= summation operator_{k}a;{k}(t)b;{k}(r) . The properties of these biorthogonal function sets are treated in detail. We consider a linear problem and the statistical properties of the fluid flow are supposed to be given. The turbulent convection may have an arbitrary distribution of spatial scales. The time evolution of the expansion coefficients a;{k} is governed by a stochastic differential equation from which we infer their averages a;{k} , autocorrelation functions a;{k}(t)a;{k *}(t+tau) , and an equation for the cross correlations a;{k}a;{l *} . The eigenfunctions of the dynamo equation (with eigenvalues lambda_{k} ) turn out to be a preferred set in terms of which our results assume their simplest form. The magnetic field of the dynamo is shown to consist of transiently excited eigenmodes whose frequency and coherence time is given by Ilambda_{k} and -1/Rlambda_{k} , respectively. The relative rms excitation level of the eigenmodes, and hence the distribution of magnetic energy over spatial scales, is determined by linear theory. An expression is derived for |a;{k}|;{2}/|a;{0}|;{2} in case the fundamental mode b;{0} has a dominant amplitude, and we outline how this expression may be evaluated. It is estimated that |a;{k}|;{2}/|a;{0}|;{2} approximately 1/N , where N is the number of convective cells in the dynamo. We show that the old problem of a short correlation time (or first-order smoothing approximation) has been partially eliminated. Finally we prove that for a simple statistically steady dynamo with finite resistivity all eigenvalues obey Rlambda_{k}<0 .
Excited nuclei in neutron star crusts
Takibayev, Nurgali; Nasirova, Diana
2012-01-01
The paper considers the chains of successive electron capture reactions by nuclei of the iron group which take place in the crystal structures of neutron star envelopes. It is shown that as a result of such reactions the daughter nuclei in excited states accumulate within certain layers of neutron star crusts. The phonon model of interactions is proposed between the excited nuclei in the crystalline structure, as well as formation of highly excited nuclear states which emit neutrons and higher energy photons.
Dynamic Testing: Toward a Multiple Exciter Test
2015-04-01
55 Defense AT&L: March–April 2015 Dynamic Testing Toward a Multiple Exciter Test Michael T. Hale n William A. Barber Hale is an electronics...has taken decades of advancements in vibration control and exciter technology. Below are a short historical path of the evolution of the discipline...toward multiple exciter /multiple degree-of-freedom (MDOF) testing, an example of an MDOF vibration system and a discussion of benefits of the
Dynamical Structure of Nuclear Excitation in Continuum
Institute of Scientific and Technical Information of China (English)
ZHANG Chun-Lei; ZHANG Huan-Qiao; ZHANG Xi-Zhen
2005-01-01
@@ Dynamical structures of collective excitation in continuum are studied by calculating the isoscalar and isovector strength as well as transition density of nuclei near the drip-line such as 28O and 34Ca. It is found that for some excited states in continuum the proton and neutron transition density calculated from isoscalar and isovector excitation at some given energies may be different, which will affect the calculation of the polarization for nuclei with N ≠ Z.
Femtosecond laser excitation of dielectric materials
DEFF Research Database (Denmark)
Wædegaard, Kristian Juncher; Balling, Peter; Frislev, Martin Thomas
2012-01-01
We report an approach to modeling the interaction between ultrashort laser pulses and dielectric materials. The model includes the excitation of carriers by the laser through strongfield excitation, collisional excitation, and absorption in the plasma consisting of conduction-band electrons formed...... during the pulse itself. It will be described how the model allows for a self-consistent description of material excitation and light propagation. The model is used to predict ablation depths and the optical properties of the sample. A comparison between the calculation and experimentally determined...
Spin Excitations in Dissipative Ferromagnetic Nanoshells
Directory of Open Access Journals (Sweden)
V.V. Kulish
2016-10-01
Full Text Available In the paper, dipole-exchange radial-angular spin excitations in a spherical ferromagnetic nanoshell are investigated. For such excitations, a differential equation for the magnetic potential is found, with account for the magnetic dipole-dipole interaction, the exchange interaction, the anisotropy effects and the dissipation. The equation is solved for the three cases – the case of a thin shell, the case of short waves and the case of radial excitations. For each of these cases, the dispersion relation and the spectrum of possible excitation frequencies are found.
The mechanisms of Excited states in enzymes
DEFF Research Database (Denmark)
Petersen, Frederic Nicolas Rønne; Bohr, Henrik
2010-01-01
Enzyme catalysis is studied on the basis of excited state processes, which are of electronic, vibrational and thermal nature. The ways of achieving the excited state, such as photo-absorption and ligand binding, are discussed and exemplified by various cases of enzymes.......Enzyme catalysis is studied on the basis of excited state processes, which are of electronic, vibrational and thermal nature. The ways of achieving the excited state, such as photo-absorption and ligand binding, are discussed and exemplified by various cases of enzymes....
Floating Rydberg crystals formed by resonant excitation
Gärttner, M; Gasenzer, T; Evers, J
2013-01-01
The dynamics of a cloud of ultra-cold Rydberg atoms is studied at off-resonant laser driving. We find that excitation crystals are formed dynamically as a consequence of interaction-induced resonant excitations. These crystals have lattice constants independent of the trap length, are spatially not localized with respect to the trap, and sensitively depend on the shape of the interaction potential. Compared to previously proposed crystals, this leads to qualitatively different results for the spatial excitation density, the Mandel $Q$ parameter, and the total number of excitations.
The mechanisms of Excited states in enzymes
DEFF Research Database (Denmark)
Petersen, Frederic Nicolas Rønne; Bohr, Henrik
2010-01-01
Enzyme catalysis is studied on the basis of excited state processes, which are of electronic, vibrational and thermal nature. The ways of achieving the excited state, such as photo-absorption and ligand binding, are discussed and exemplified by various cases of enzymes.......Enzyme catalysis is studied on the basis of excited state processes, which are of electronic, vibrational and thermal nature. The ways of achieving the excited state, such as photo-absorption and ligand binding, are discussed and exemplified by various cases of enzymes....
Local pair natural orbitals for excited states.
Helmich, Benjamin; Hättig, Christof
2011-12-07
We explore how in response calculations for excitation energies with wavefunction based (e.g., coupled cluster) methods the number of double excitation amplitudes can be reduced by means of truncated pair natural orbital (PNO) expansions and localized occupied orbitals. Using the CIS(D) approximation as a test model, we find that the number of double excitation amplitudes can be reduced dramatically with minor impact on the accuracy if the excited state wavefunction is expanded in state-specific PNOs generated from an approximate first-order guess wavefunction. As for ground states, the PNO truncation error can also for excitation energies be controlled by a single threshold related to generalized natural occupation numbers. The best performance is found with occupied orbitals which are localized by the Pipek-Mezey localization. For a large test set of excited states we find with this localization that already a PNO threshold of 10(-8)-10(-7), corresponding to an average of only 40-80 PNOs per pair, is sufficient to keep the PNO truncation error for vertical excitation energies below 0.01 eV. This is a significantly more rapid convergence with the number doubles amplitudes than in domain-based local response approaches. We demonstrate that the number of significant excited state PNOs scales asymptotically linearly with the system size in the worst case of completely delocalized excitations and sub-linearly whenever the chromophore does not increase with the system size. Moreover, we observe that the flexibility of state-specific PNOs to adapt to the character of an excitation allows for an almost unbiased treatment of local, delocalized and charge transfer excited states.
Local pair natural orbitals for excited states
Helmich, Benjamin; Hättig, Christof
2011-12-01
We explore how in response calculations for excitation energies with wavefunction based (e.g., coupled cluster) methods the number of double excitation amplitudes can be reduced by means of truncated pair natural orbital (PNO) expansions and localized occupied orbitals. Using the CIS(D) approximation as a test model, we find that the number of double excitation amplitudes can be reduced dramatically with minor impact on the accuracy if the excited state wavefunction is expanded in state-specific PNOs generated from an approximate first-order guess wavefunction. As for ground states, the PNO truncation error can also for excitation energies be controlled by a single threshold related to generalized natural occupation numbers. The best performance is found with occupied orbitals which are localized by the Pipek-Mezey localization. For a large test set of excited states we find with this localization that already a PNO threshold of 10-8-10-7, corresponding to an average of only 40-80 PNOs per pair, is sufficient to keep the PNO truncation error for vertical excitation energies below 0.01 eV. This is a significantly more rapid convergence with the number doubles amplitudes than in domain-based local response approaches. We demonstrate that the number of significant excited state PNOs scales asymptotically linearly with the system size in the worst case of completely delocalized excitations and sub-linearly whenever the chromophore does not increase with the system size. Moreover, we observe that the flexibility of state-specific PNOs to adapt to the character of an excitation allows for an almost unbiased treatment of local, delocalized and charge transfer excited states.
PROPENSITY RULES IN Ar—IMPACT EXCITATION OF H— IN DOUBLY EXCITED STATES
Institute of Scientific and Technical Information of China (English)
NaotoKoyama; MotoiMaeda; 等
1990-01-01
We have theoretically investigated excitation processes of H- ions in the doubly excited states by Ar-impact,using the impulse approximation and employing the hyperspherical wavefunctions.We have found that the H- ion in the double excited states tends to conserve its initial states as a “floppy linear triatomic molecule” during excitation processes except for the restriction arising from the Pauli exclusion principle for two atomic electrons.
Caroline Duc
2013-01-01
As the first and last proton-lead run of 2013 draws to a close, the extensive upgrade and maintenance programme of the LHC's first long shutdown (LS1) is about to get under way. The LHC has provided physicists with a huge quantity of data to analyse since the first physics run in 2009. Now it's time for the machine, along with CERN's other accelerators, to get a facelift. LS1 will start on 13 February 2013, but this doesn’t mean that life at the Laboratory will be any less rich and exciting. Although there will be no collisions for a period of almost two years, the whole CERN site will be a hive of activity, with large-scale work under way to modernise the infrastructure and prepare the LHC for operation at higher energy. "A whole series of renovation work will be carried out around the LHC during LS1,” explains Simon Baird, deputy head of the EN Department. "The key driver is of course the consolidation of the 10,170 high-curren...
A large electrically excited synchronous generator
DEFF Research Database (Denmark)
2014-01-01
adjacent neighbouring poles. In this way, a large electrically excited synchronous generator (EESG) is provided that readily enables a relatively large number of poles, compared to a traditional EESG, since the excitation coil in this design provides MMF for all the poles, whereas in a traditional EESG...
Study of excited nucleons and their structure
Energy Technology Data Exchange (ETDEWEB)
Burkert, Volker D. [JLAB, Newport News, VA (United States)
2014-01-01
Recent advances in the study of excited nucleons are discussed. Much of the progress has been achieved due to the availability of high precision meson production data in the photoproduction and electroproduction sectors, the development of multi-channel partial wave analysis techniques, and advances in Lattice QCD with predictions of the full excitation spectrum.
What Gets a Cell Excited? Kinky Curves
Kay, Alan R.
2014-01-01
Hodgkin and Huxley's (5) revealing the origins of cellular excitability is one of the great triumphs of physiology. In an extraordinarily deft series of papers, they were able to measure the essential electrical characteristics of neurons and synthesize them into a quantitative model that accounts for the excitability of neurons and other…
Mutual Excitation in Eurozone Sovereign CDS
Aït-Sahalia, Y.; Laeven, R.J.A.; Pelizzon, L.
2013-01-01
We study self- and cross-excitation of shocks in the sovereign CDS market, on the basis of a large database of Eurozone sovereign CDS spreads. We adopt a multivariate setting with credit default intensities driven by mutually exciting jump processes, to capture the salient features observed in the d
Multimode optical fibers: steady state mode exciter.
Ikeda, M; Sugimura, A; Ikegami, T
1976-09-01
The steady state mode power distribution of the multimode graded index fiber was measured. A simple and effective steady state mode exciter was fabricated by an etching technique. Its insertion loss was 0.5 dB for an injection laser. Deviation in transmission characteristics of multimode graded index fibers can be avoided by using the steady state mode exciter.
Excitations of Neodymium Ions in Praseodymium
DEFF Research Database (Denmark)
Wulff, M.; Jensen, J.; Mackintosh, A.R.;
1983-01-01
The excitations of Nd ions dissolved in Pr have been studied by inelastic neutron scattering. A crystal-field level at about 1.2 meV interferes strongly with the host excitations. In the antiferromagnetic phase, another level is observed about 0.5 meV above the ground-state, which is split...
S-parameters for weakly excited slots
DEFF Research Database (Denmark)
Albertsen, Niels Christian
1999-01-01
A simple approach to account for parasitic effects in weakly excited slots cut in the broad wall of a rectangular waveguide is proposed......A simple approach to account for parasitic effects in weakly excited slots cut in the broad wall of a rectangular waveguide is proposed...
Coulomb excitation of radioactive {sup 79}Pb
Energy Technology Data Exchange (ETDEWEB)
Lister, C.J.; Blumenthal, D.; Davids, C.N. [and others
1995-08-01
The technical challenges expected in experiments with radioactive beams can already be explored by using ions produced in primary reactions. In addition, the re-excitation of these ions by Coulomb excitation allows a sensitive search for collective states that are well above the yrast line. We are building an experiment to study Coulomb excitation of radioactive ions which are separated from beam particles by the Fragment Mass Analyzer. An array of gamma detectors will be mounted at the focal plane to measure the gamma radiation following re-excitation. Five Compton-suppressed Ge detectors and five planar LEPS detectors will be used. The optimum experiment of this type appears to be the study of {sup 79}Rb following the {sup 24}Mg ({sup 58}Ni,3p) reaction. We calculate that about 5 x 10{sup 5} {sup 79}Rb nuclei/second will reach the excitation foil. This rubidium isotope was selected for study as it is strongly produced and is highly deformed, so easily re-excited. The use of a {sup 58}Ni re-excitation foil offers the best yields. After re-excitation the ions will be subsequently transported into a shielded beamdump to prevent the accumulation of activity.
Simultaneous multislice excitation by parallel transmission
Poser, Benedikt A; Anderson, Robert James; Guérin, Bastien; Setsompop, Kawin; Deng, Weiran; Mareyam, Azma; Serano, Peter; Wald, Lawrence L; Stenger, V Andrew
2014-01-01
PURPOSE: A technique is described for simultaneous multislice (SMS) excitation using radiofrequency (RF) parallel transmission (pTX). METHODS: Spatially distinct slices are simultaneously excited by applying different RF frequencies on groups of elements of a multichannel transmit array. The localiz
Mutual excitation in Eurozone sovereign CDS
Aït-Sahalia, Y.; Laeven, R.J.A.; Pelizzon, L.
2014-01-01
We study self- and cross-excitation of shocks in the Eurozone sovereign CDS market. We adopt a multivariate setting with credit default intensities driven by mutually exciting jump processes, to capture the salient features observed in the data, in particular, the clustering of high default probabil
Evolution of Excited Convective Cells in Plasmas
DEFF Research Database (Denmark)
Pécseli, Hans; Juul Rasmussen, Jens; Sugai, H.
1984-01-01
Convective cells are excited externally in a fully ionized magnetized plasma and their space-time evolution is investigated by two-dimensional potential measurements. A positive cell is excited externally by control of the end losses in the 'scrape off' layer of a plasma column produced by surface...
Excitations in Topological Superfluids and Superconductors
Wu, Hao
In this thesis I present the theoretical work on Fermionic surface states, and %the bulk Bosonic collective excitations in topological superfluids and superconductors. Broken symmetries %Bulk-edge correspondence in topological condensed matter systems have implications for the spectrum of Fermionic excitations confined on surfaces or topological defects. (Abstract shortened by ProQuest.).
Nonlinear Excitations in Inflationary Power Spectra
Miranda, Vinicius; He, Chen; Motohashi, Hayato
2016-01-01
We develop methods to calculate the curvature power spectrum in models where features in the inflaton potential nonlinearly excite modes and generate high frequency features in the spectrum. The first nontrivial effect of excitations generating further excitations arises at third order in deviations from slow roll. If these further excitations are contemporaneous, the series can be resummed, showing the exponential sensitivity of the curvature spectrum to potential features. More generally, this exponential approximation provides a power spectrum template which nonlinearly obeys relations between excitation coefficients and whose parameters may be appropriately adjusted. For a large sharp step in the potential, it greatly improves the analytic power spectrum template and its dependence on potential parameters. For axionic oscillations in the potential, it corrects the mapping between the potential and the amplitude, phase and zero point of the curvature oscillations, which might otherwise cause erroneous infe...
EFFECTS OF CONSTANT EXCITATION ON LOCAL BIFURCATION
Institute of Scientific and Technical Information of China (English)
WU Zhi-qiang; CHEN Yu-shu
2006-01-01
The effects of the constant excitation on the local bifurcation of the periodic solutions in the 1:2 internal resonant systems were analyzed based on the singularity theory. It is shown that the constant excitation make influence only when there exist some nonlinear terms, in the oscillator with lower frequency. Besides acting as main bifurcation parameter, the constant excitation, together with coefficients of some nonlinear terms,may change the values of unfolding parameters and the type of the bifurcation. Under the non-degenerate cases, the effect of the third order terms can be neglected.
Symmetry characterization of electrons and lattice excitations
Directory of Open Access Journals (Sweden)
Schober H.
2012-03-01
Full Text Available Symmetry concerns all aspects of a physical system from the electronic orbitals to structural and magnetic excitations. In this article we will try to elaborate the fundamental connection between symmetry and excitations. As excitations are manyfold in physical systems it is impossible to treat them exhaustively. We thus concentrate on the two topics of Bloch electrons and phonons. These two examples are complementary in the sense that Bloch electrons describe single particles in an external periodic potential while phonons exemplify a decoupled system of interacting particles. The way we develop the argument gives as by-product a short account of molecular orbitals and molecular vibrations.
Ekectron-Impact Excitation of C+
Pearce, A. J.; Ballance, C. P.; Loch, S. D.; Pindzola, M. S.
2015-05-01
Electron-impact excitation cross sections are calculated for ground and excited states of C+ using the R-matrix with pseudo-states method. We used the configurations 1s2 2s2 nl (3 s pnl (2 p 4 P,2 D,2 S transitions are in good agreement with experiment. Combined with previous calculations for C and Cq+ (q = 2- 5), sufficient excitation, ionization, and recombination atomic data is now available to generate high quality collisional-radiative coefficients for the entire C isonuclear sequence. Work supported in part by grants from NASA, NSF, and DOE.
New Vistas of the Structure of Neutron-Rich Nuclei - Single Particle States and g-FACTORS
Ramayya, A. V.; Hamilton, J. H.; Luo, Y. X.; Zhu, S. J.; Hwang, J. K.; Rasmussen, J. O.; Ter-Akopian, G. M.; Daniel, A. V.; Brewer, N.; Oganessian, Y.
2012-01-01
Prompt γ-γ-γ coincidence studies of neutron-rich nuclei populated in the spontaneous fission of 252Cf led to the discoveries of many important processes like neutron-less binary and ternary fragmentation in spontaneous fission, binary and ternary hot fission modes, hyper-deformation, cluster radioactivity and quasi-molecular states in ternary fission. The high statistics data, 5.7 × 1011 triples and higher folds, opened up discoveries of new band structures and significant extensions of previously known bands. These data were used to measure the angular correlations of cascades of γ-rays from the excited states of neutron-rich fission fragments stopped in an unmagnetized iron foil. By using this γ-γ angular correlation technique, the single particle configurations of the known rotational bands were assigned and confirmed in the present work. In other words, the multipole mixing ratios of ΔI=1 transitions in the rotational bands were measured. These experimental mixing ratios are compred with the theoretical ones of particle and axial-rotor model. The configuration of the ground states in 109,111Ru were, for the first time, assigned. And magnetic g-factors of excited states in even-even neutron-rich nuclei were meaured, too. Two sets of ΔI=1 alternating parity doublets with opposite parities were observed in Ba and Ce isotopes. The B(E1)/B(E2) branching ratios and D0 values may indicate that the octupole correlations are strong in Ba and Ce isotopes because of the Z=56 and N=88 octupole shell gaps. High-spin, even-parity bands in neutron-rich 108,110,112Ru nuclei indicate two-phonon quasi-gamma bands in 110,112Ru.
Hydrogen Bonds in Excited State Proton Transfer
Horke, D. A.; Watts, H. M.; Smith, A. D.; Jager, E.; Springate, E.; Alexander, O.; Cacho, C.; Chapman, R. T.; Minns, R. S.
2016-10-01
Hydrogen bonding interactions between biological chromophores and their surrounding protein and solvent environment significantly affect the photochemical pathways of the chromophore and its biological function. A common first step in the dynamics of these systems is excited state proton transfer between the noncovalently bound molecules, which stabilizes the system against dissociation and principally alters relaxation pathways. Despite such fundamental importance, studying excited state proton transfer across a hydrogen bond has proven difficult, leaving uncertainties about the mechanism. Through time-resolved photoelectron imaging measurements, we demonstrate how the addition of a single hydrogen bond and the opening of an excited state proton transfer channel dramatically changes the outcome of a photochemical reaction, from rapid dissociation in the isolated chromophore to efficient stabilization and ground state recovery in the hydrogen bonded case, and uncover the mechanism of excited state proton transfer at a hydrogen bond, which follows sequential hydrogen and charge transfer processes.
Simulation Model of Brushless Excitation System
Directory of Open Access Journals (Sweden)
Ahmed N.A. Alla
2007-01-01
Full Text Available Excitation system is key element in the dynamic performance of electric power systems, accurate excitation models are of great importance in simulating and investigating the power system transient phenomena. Parameter identification of the Brushless excitation system was presented. First a block diagram for the EXS parameter was proposed based on the documents and maps in the power station. To identify the parameters of this model, a test procedure to obtain step response, was presented. Using the Genetic Algorithm with the Matlab-software it was possible to identify all the necessary parameters of the model. Using the same measured input signals the response from the standard model showed nearly the same behavior as the excitation system.
Rowan, D. R.
1989-01-01
The development and implementation of a C-band exciter for use with the Block IV Receiver-Exciter Subsystem at Deep Space Station 14 (DSS-14) has been completed. The exciter supplements the standard capabilities of the Block IV system by providing a drive signal for the C-band transmitter while generating coherent translation frequencies for C-band (5-GHz) to S-band (2.2- to 2.3-GHz) Doppler extraction, C-band to L-band (1.6-GHz) zero delay measurements, and a level calibrated L-band test signal. Exciter functions are described, and a general explanation and description of the C-band uplink controller is presented.
Language identification using excitation source features
Rao, K Sreenivasa
2015-01-01
This book discusses the contribution of excitation source information in discriminating language. The authors focus on the excitation source component of speech for enhancement of language identification (LID) performance. Language specific features are extracted using two different modes: (i) Implicit processing of linear prediction (LP) residual and (ii) Explicit parameterization of linear prediction residual. The book discusses how in implicit processing approach, excitation source features are derived from LP residual, Hilbert envelope (magnitude) of LP residual and Phase of LP residual; and in explicit parameterization approach, LP residual signal is processed in spectral domain to extract the relevant language specific features. The authors further extract source features from these modes, which are combined for enhancing the performance of LID systems. The proposed excitation source features are also investigated for LID in background noisy environments. Each chapter of this book provides the motivatio...
Wideband MEMS Resonator Using Multifrequency Excitation
Jaber, Nizar
2016-03-09
We demonstrate the excitation of combination resonances of additive and subtractive types and their exploitations to realize a large bandwidth micro-machined resonator of large amplitude even at higher harmonic modes of vibrations. The investigation is conducted on a Microelectromechanical systems (MEMS) clamped-clamped microbeam fabricated using polyimide as a structural layer coated with nickel from top and chromium and gold layers from bottom. The microbeam is excited by a two-source harmonic excitation, where the first frequency source is swept around the targeted resonance (first or third mode of vibration) while the second source frequency is kept fixed. We report for the first time a large bandwidth and large amplitude response near the higher order modes of vibration. Also, we show that by properly tuning the frequency and amplitude of the excitation force, the frequency bandwidth of the resonator is controlled.
Faraday waves under time-reversed excitation.
Pietschmann, Dirk; Stannarius, Ralf; Wagner, Christian; John, Thomas
2013-03-01
Do parametrically driven systems distinguish periodic excitations that are time mirrors of each other? Faraday waves in a Newtonian fluid are studied under excitation with superimposed harmonic wave forms. We demonstrate that the threshold parameters for the stability of the ground state are insensitive to a time inversion of the driving function. This is a peculiarity of some dynamic systems. The Faraday system shares this property with standard electroconvection in nematic liquid crystals [J. Heuer et al., Phys. Rev. E 78, 036218 (2008)]. In general, time inversion of the excitation affects the asymptotic stability of a parametrically driven system, even when it is described by linear ordinary differential equations. Obviously, the observed symmetry has to be attributed to the particular structure of the underlying differential equation system. The pattern selection of the Faraday waves above threshold, on the other hand, discriminates between time-mirrored excitation functions.
Evaluation of Excitation Function for 64Zn
Institute of Scientific and Technical Information of China (English)
2008-01-01
<正>Present work concerns the evaluated neutron induced excitation function data for 64Zn, and mainly on (n, γ) reaction channel. The related experimental data were collected, analyzed and corrected for 64Zn
Evaluation of Excitation Function for 182Ta
Institute of Scientific and Technical Information of China (English)
2008-01-01
<正>Present work concerns the evaluated neutron induced excitation function data for 182Ta, and mainly on (n, γ) reaction channel. The related experimental data were collected, analyzed and corrected for 182Ta
Students Excited by Stellar Discovery
2011-02-01
In the constellation of Ophiuchus, above the disk of our Milky Way Galaxy, there lurks a stellar corpse spinning 30 times per second -- an exotic star known as a radio pulsar. This object was unknown until it was discovered last week by three high school students. These students are part of the Pulsar Search Collaboratory (PSC) project, run by the National Radio Astronomy Observatory (NRAO) in Green Bank, WV, and West Virginia University (WVU). The pulsar, which may be a rare kind of neutron star called a recycled pulsar, was discovered independently by Virginia students Alexander Snider and Casey Thompson, on January 20, and a day later by Kentucky student Hannah Mabry. "Every day, I told myself, 'I have to find a pulsar. I better find a pulsar before this class ends,'" said Mabry. When she actually made the discovery, she could barely contain her excitement. "I started screaming and jumping up and down." Thompson was similarly expressive. "After three years of searching, I hadn't found a single thing," he said, "but when I did, I threw my hands up in the air and said, 'Yes!'." Snider said, "It actually feels really neat to be the first person to ever see something like that. It's an uplifting feeling." As part of the PSC, the students analyze real data from NRAO's Robert C. Byrd Green Bank Telescope (GBT) to find pulsars. The students' teachers -- Debra Edwards of Sherando High School, Leah Lorton of James River High School, and Jennifer Carter of Rowan County Senior High School -- all introduced the PSC in their classes, and interested students formed teams to continue the work. Even before the discovery, Mabry simply enjoyed the search. "It just feels like you're actually doing something," she said. "It's a good feeling." Once the pulsar candidate was reported to NRAO, Project Director Rachel Rosen took a look and agreed with the young scientists. A followup observing session was scheduled on the GBT. Snider and Mabry traveled to West Virginia to assist in the
Recursive design of nonlinear H∞ excitation controller
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
This work is concerned with the problem of L2 gain disturbance attenuation for nonlinear systems and nonlinear robust control for power systems. In terms of the recurrence design approach proposed, the nonnegative solution of dissipative inequality and the storage function of nonlinear H∞ control for a generator excitation system are acquired. From this storage function, the excitation controller is constructed. Moreover, simulation results manifest the effectiveness of this design method.
Care of the patient in excited delirium.
Gordon, Cheryl; Schmelzer, Marilee
2013-03-01
Patients with excited delirium present a challenge to both law enforcement and health care personnel because handcuffs, the traditional method used to keep persons from harming themselves and others, may be fatal. The patient's survival depends upon rapid recognition and treatment, including chemical sedation, decreased environmental stimulation, intravenous fluids, and other supportive interventions. Excited delirium protocols should be established to ensure rapid and appropriate treatment to ensure patient survival and the safety of those caring for them.
Rearrangements in ground and excited states
de Mayo, Paul
1980-01-01
Rearrangements in Ground and Excited States, Volume 3 presents essays on the chemical generation of excited states; the cis-trans isomerization of olefins; and the photochemical rearrangements in trienes. The book also includes essays on the zimmerman rearrangements; the photochemical rearrangements of enones; the photochemical rearrangements of conjugated cyclic dienones; and the rearrangements of the benzene ring. Essays on the photo rearrangements via biradicals of simple carbonyl compounds; the photochemical rearrangements involving three-membered rings or five-membered ring heterocycles;
Propagation and excitation of graphene plasmon polaritons
DEFF Research Database (Denmark)
Zhu, Xiaolong; Yan, Wei; Jeppesen, Claus
2013-01-01
We theoretically investigate the propagation of graphene plasmon polaritons in graphene nanoribbon waveguides and experimentally observe the excitation of the graphene plasmon polaritons in a continuous graphene monolayer. We show that graphene nanoribbon bends do not induce any additional loss...... and nanofocusing occurs in a tapered graphene nanoriboon, and we experimentally demonstrate the excitation of graphene plasmon polaritonss in a continuous graphene monolayer assisted by a two-dimensional subwavelength silicon grating....
Electron impact vibrational excitation of methyl chloride
Sakaamini, Ahmad; Hargreaves, Leigh; Khakoo, Murtadha
2016-05-01
Low energy differential cross sections and excitation functions for vibrational excitation of CH3 Cl are presented for five vibrational features in the electron energy loss spectrum of this molecule. Electron energies range from 1 eV to 15 eV and scattering angles from 10o to 125o. Results will be compared to existing data for CH3 Cl in the literature. Funded by a NSF-AMOP-RUI Grant.
Magnesium induces neuronal apoptosis by suppressing excitability
Dribben, W H; Eisenman, L N; Mennerick, S
2010-01-01
In clinical obstetrics, magnesium sulfate (MgSO4) use is widespread, but effects on brain development are unknown. Many agents that depress neuronal excitability increase developmental neuroapoptosis. In this study, we used dissociated cultures of rodent hippocampus to examine the effects of Mg++ on excitability and survival. Mg++-induced caspase-3-associated cell loss at clinically relevant concentrations. Whole-cell patch-clamp techniques measured Mg++ effects on action potential threshold,...
Fast pulsed excitation wiggler or undulator
van Steenbergen, Arie
1990-01-01
A fast pulsed excitation, electromagnetic undulator or wiggler, employing geometrically alternating substacks of thin laminations of ferromagnetic material, together with a single turn current loop excitation of the composite assembly, of such shape and configuration that intense, spatially alternating, magnetic fields are generated; for use as a pulsed mode undulator or wiggler radiator, for use in a Free Electron Laser (FEL) type radiation source or, for use in an Inverse Free Electron Laser (IFEL) charged particle accelerator.
Search for Excited Leptons at LEP
Achard, P; Aguilar-Benítez, M; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alviggi, M G; Anderhub, H; Andreev, V P; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Bajo, A; Baksay, G; Baksay, L; Baldew, S V; Banerjee, S; Banerjee, Sw; Barczyk, A; Barillère, R; Bartalini, P; Basile, M; Batalova, N; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Bellucci, L; Berbeco, R; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Biasini, M; Biglietti, M; Biland, A; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böhm, A; Boldizsar, L; Borgia, B; Bottai, S; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brochu, F; Burger, J D; Burger, W J; Cai, X D; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada, M; Chamizo-Llatas, M; Chang, Y H; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chiefari, G; Cifarelli, Luisa; Cindolo, F; Clare, I; Clare, R; Coignet, G; Colino, N; Costantini, S; de la Cruz, B; Cucciarelli, S; van Dalen, J A; De Asmundis, R; Déglon, P L; Debreczeni, J; Degré, A; Dehmelt, K; Deiters, K; Della Volpe, D; Delmeire, E; Denes, P; De Notaristefani, F; De Salvo, A; Diemoz, M; Dierckxsens, M; Dionisi, C; Dittmar, M; Doria, A; Dova, M T; Duchesneau, D; Duda, M; Echenard, B; Eline, A; El-Hage, A; El-Mamouni, H; Engler, A; Eppling, F J; Extermann, P; Falagán, M A; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, M; Ferguson, T; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisher, W; Fisk, I; Forconi, G; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gataullin, M; Gentile, S; Giagu, S; Gong, Z F; Grenier, G; Grimm, O; Grünewald, M W; Guida, M; van Gulik, R; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hakobyan, R S; Hansen, J M; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hirschfelder, J; Hofer, H; Hohlmann, M; Holzner, G; Hou, S R; Hu, Y; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Käfer, D; Kaur, M; Kienzle-Focacci, M N; Kim, J K; Kirkby, Jasper; Kittel, E W; Klimentov, A; König, A C; Kopal, M; Koutsenko, V F; Kräber, M H; Krämer, R W; Krüger, A; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Le Goff, J M; Leiste, R; Levtchenko, M; Levchenko, P M; Li, C; Likhoded, S; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lü, Y S; Luci, C; Luminari, L; Lustermann, W; Ma Wen Gan; Malgeri, L; Malinin, A; Maña, C; Mans, J; Martin, J P; Marzano, F; Mazumdar, K; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Mihul, A; Milcent, H; Mirabelli, G; Mnich, J; Mohanty, G B; Muanza, G S; Muijs, A J M; Musicar, B; Musy, M; Nagy, S; Natale, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Nisati, A; Nowak, H; Ofierzynski, R A; Organtini, G; Pal, I; Palomares, C; Paolucci, P; Paramatti, R; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Pedace, M; Pensotti, S; Perret-Gallix, D; Petersen, B; Piccolo, D; Pierella, F; Pioppi, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Pothier, J; Prokofev, D; Prokofiev, D O; Quartieri, J; Rahal-Callot, G; Rahaman, M A; Raics, P; Raja, N; Ramelli, R; Rancoita, P G; Ranieri, R; Raspereza, A V; Razis, P A; Ren, D; Rescigno, M; Reucroft, S; Riemann, S; Riles, K; Roe, B P; Romero, L; Rosca, A; Rosier-Lees, S; Roth, S; Rosenbleck, C; Rubio, J A; Ruggiero, G; Rykaczewski, H; Sakharov, A; Saremi, S; Sarkar, S; Salicio, J; Sánchez, E; Schäfer, C; Shchegelskii, V; Schopper, Herwig Franz; Schotanus, D J; Sciacca, C; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shumilov, E; Shvorob, A V; Son, D; Souga, C; Spillantini, P; Steuer, M; Stickland, D P; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Sushkov, S; Suter, H; Swain, J D; Szillási, Z; Tang, X W; Tarjan, P; Tauscher, Ludwig; Taylor, L; Tellili, B; Teyssier, D; Timmermans, C; Ting, Samuel C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tung, K L; Ulbricht, J; Valente, E; Van de Walle, R T; Vásquez, R; Veszpremi, V; Vesztergombi, G; Vetlitskii, I; Vicinanza, D; Viertel, Gert M; Villa, S; Vivargent, M; Vlachos, S; Vodopyanov, I; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Wadhwa, M; Wang, Q; Wang, X L; Wang, Z M; Weber, M; Wienemann, P; Wilkens, H; Wynhoff, S; Xia, L; Xu, Z Z; Yamamoto, J; Yang, B Z; Yang, C G; Yang, H J; Yang, M; Yeh, S C; Zalite, A; Zalite, Yu; Zhang, Z P; Zhao, J; Zhu, G Y; Zhu, R Y; Zhuang, H L; Zichichi, A; Zimmermann, B; Zöller, M
2003-01-01
A search for charged and neutral excited leptons is performed in 217 pb-1 of data collected with the L3 detector at LEP at centre-of-mass energies up to 209 GeV. The pair- and single-production mechanisms are investigated and no signals are detected. Combining with L3 results from searches at lower centre-of-mass energies, gives improved limits on the masses and couplings of excited leptons.
Excited States in Staggered Meson Propagators
Bernard, C; De Tar, C; Gottlieb, Steven; Gregory, E B; Heller, U M; Osborn, J; Sugar, R; Toussaint, D; Louis, St; Gottlieb, Steven
2003-01-01
We report on preliminary results from multi-particle fits to meson propagators with three flavors of light dynamical quarks. We are able to measure excited states in propagators with pion quantum numbers, which we interpret as the pion 2S state, and is evidence of locality of the action. In the a_0 (0^{++}) propagators we find evidence for excited states which are probably the expected decay channels, pi+eta and K+Kbar.
Connectivity, excitability and activity patterns in neuronal networks
le Feber, Jakob; Stoyanova, Irina; Chiappalone, Michela
2014-01-01
Extremely synchronized firing patterns such as those observed in brain diseases like epilepsy may result from excessive network excitability. Although network excitability is closely related to (excitatory) connectivity, a direct measure for network excitability remains unavailable. Several methods
Stimulated excitation electron microscopy and spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Howie, A.
2015-04-15
Recent advances in instrumentation for electron optics and spectroscopy have prompted exploration of ultra-low excitations such as phonons, bond vibrations and Johnson noise. These can be excited not just with fast electrons but also thermally or by other external sources of radiation. The near-field theory of electron energy loss and gain provides a convenient platform for analysing these processes. Possibilities for selected phonon mapping and imaging are discussed. Effects should certainly be observable in atomic resolution structure imaging but diffraction contrast imaging could perhaps be more informative. Additional exciting prospects to be explored include the transition from phonon excitation to single atom recoil and the boosting of energy loss and gain signals with tuned laser illumination. - Highlights: • Electron energy gains and losses measure thermal or laser boosting of excitations. • Electron energy gains and losses are conveniently analysed by near field theory. • Diffraction contrast theory is relevant for phonon imaging by electrons. • The transition from phonon excitation to single atom recoil deserves study.
Excitation of annual polar motion by atmosphere and ocean
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
The quantitative result of annual polar motion excitation by the ocean is presented for the first time. The atmosphericexcitation amounts to more than double of the oceanic excitation. The sum of atmospheric and oceanic excitations approximates more to the observed annual polar motion excitation, compared with atmospheric excitation only. This suggests that the atmosphere and ocean are the main excitation sources of annual polar motion.
How much double excitation character do the lowest excited states of linear polyenes have?
Starcke, Jan Hendrik; Wormit, Michael; Schirmer, Jochen; Dreuw, Andreas
2006-10-01
Doubly excited states play important roles in the low-energy region of the optical spectra of polyenes and their investigation has been subject of theoretical and experimental studies for more than 30 years now and still is in the focus of ongoing research. In this work, we address the question why doubly excited states play a role in the low-energy region of the optical spectrum of molecular systems at all, since from a naive point of view one would expect their excitation energy approximately twice as large as the one of the corresponding single excitation. Furthermore, we show that extended-ADC(2) is well suited for the balanced calculation of the low-lying excited 21Ag-, 11Bu- and 11Bu+ states of long all- trans polyenes, which are known to possess substantial double excitation character. A careful re-investigation of the performance of TDDFT calculations for these states reveals that the previously reported good performance for the 21Ag- state relies heavily on fortuitous cancellation of errors. Finally, the title question is answered such that for short polyenes the lowest excited 21Ag- and 11Bu- states can clearly be classified as doubly excited, whereas the 11Ag- ground state is essentially represented by the (ground-state) HF determinant. For longer polyenes, in addition to increasing double excitation contributions in the 21Ag- and 11Bu- states, the ground state itself aquires substantial double excitation character (45% in C 22H 24), so that the transition from the ground state to these excited states should not be addressed as the excitation of two electrons relative to the 11Ag- ground state.
Multi-quasiparticle Excitations in 145Tb
Institute of Scientific and Technical Information of China (English)
ZhengYong; ZhouXiaohong; ZhangYuhu; T.Hayakawa; M.Oshima; T.Toh; T.Shizuma; J.Katakura; Y.Hatsukawa; M.Matsuda; H.Kusakari; M.Sugawara; K.Furuno; T.Komatsubara
2003-01-01
Study of in-beam γ-ray spectroscopy of 145Tb has been carried out by using 118Sn (32 S, 1p4n) 145Tb reaction. Excitation functions, X-γ-t and γ-γ-t coincidences and γ-ray anisotropies were measured. Here, t refers to the relative time difference between any two coincident γ-rays detected within ±200 ns. A level scheme of 14tTb, including 81 γ-transitions as shown in Fig.l, has been established up to 7.4 MeV in excitation energy and spinparity assignments for most of the observed levels have been done. The level structure shows characteristics of spherical nucleus. The observed states with excitation energies less than 2 MeV are interpreted by coupling an h11/2 proton to the 2+, 4+ and 3- core excitations in 144Gd. The excitation energies of these states fit wellin to the systematics of the neighboring odd-A N=80 isotones, and are well reproduced by the quasiparticle-cluster interaction calculations[1]. Semi-empirical shell model calculations[2] have been done for the higher-lying levels. The results clearly reveal the characteristic features of multiparticle configurations in a spherical nucleus. Specific configurations are proposed for the yrast and some non-yrast levels.
Topological Excitations in Quantum Spin Systems
Directory of Open Access Journals (Sweden)
Ranjan Chaudhury
2013-01-01
Full Text Available The origin and significance of topological excitations in quantum spin models in low dimensions are presented in detail. Besides a general review, our own work in this area is described in great depth. Apart from theoretical analysis of the existence and properties of spin vortices and antivortices, the possible experimental consequences and signatures are also highlighted. In particular, the distinguishing features between the even and odd charged topological excitations are brought out through a detailed analysis of the topological term in the quantum action. Moreover, an interesting symmetry property is predicted between the excitations from a ferromagnetic model and an antiferromagnetic model. Through a novel approach of ours, a bridge is established between field theoretical formalism and the well-known statistical mechanical treatment of Berezinskii-Kosterlitz-Thouless (BKT transition involving these topological excitations. Furthermore, a detailed phenomenological analysis of the experimentally observed static and dynamic magnetic properties of the layered magnetic materials, possessing XY anisotropy in the in-plane spin-spin couplings, is undertaken to test the theoretical predictions regarding the behaviour of these excitations. The importance and the crucial role of quantum spin fluctuations in these studies are also brought out very clearly by our analysis.
Theory of elementary excitations in quasiperiodic structures
Albuquerque, E. L.; Cottam, M. G.
2003-03-01
The aim of this work is to present a comprehensive and up-to-date review of the main physical properties (such as energy profiles, localization, scale laws, multifractal analysis, transmission spectra, transmission fingerprints, electronic structures, magnetization curves and thermodynamic properties) of the elementary excitations that can propagate in multilayered structures with constituents arranged in a quasiperiodic fashion. These excitations include plasmon-polaritons, spin waves, light waves and electrons, among others. A complex fractal or multifractal profile of the energy spectra is the common feature among these excitations. The quasiperiodic property is formed by the incommensurate arrangement of periodic unit cells and can be of the type referred to as deterministic (or controlled) disorder. The resulting excitations are characterized by the nature of their Fourier spectrum, which can be dense pure point (as for the Fibonacci sequence) or singular continuous (as for the Thue-Morse and double-period sequences). These sequences are described in terms of a series of generations that obey particular recursion relations, and they can be considered as intermediate systems between a periodic crystal and the random amorphous solids, thus defining a novel description of disorder. A discussion is also included of some spectroscopic techniques used to probe the excitations, emphasizing Raman and Brillouin light scattering.
Inelastic scattering of {sup 9}Li and excitation mechanism of its first excited state
Energy Technology Data Exchange (ETDEWEB)
Al Falou, H. [Astronomy and Physics Department, Saint Mary' s University, Halifax, Nova Scotia B3H 3C3 (Canada); TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Kanungo, R., E-mail: ritu@triumf.ca [Astronomy and Physics Department, Saint Mary' s University, Halifax, Nova Scotia B3H 3C3 (Canada); Andreoiu, C.; Cross, D.S. [Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); Davids, B.; Djongolov, M. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Gallant, A.T. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Department of Physics, University of British Columbia, British Columbia V6T 1Z4 (Canada); Galinski, N.; Howell, D. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); Kshetri, R.; Niamir, D. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Orce, J.N. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Department of Physics, University of the Western Cape, P/B X17, Bellville, ZA-7535 (South Africa); Shotter, A.C. [Department of Physics and Astronomy, University of Edinburgh, Edinburgh (United Kingdom); Sjue, S. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Tanihata, I. [Research Center for Nuclear Physics, Osaka University, Mihogaoka, Ibaraki, Osaka 567 0047 (Japan); Thompson, I.J. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Triambak, S. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Uchida, M. [Astronomy and Physics Department, Saint Mary' s University, Halifax, Nova Scotia B3H 3C3 (Canada); Walden, P. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Wiringa, R.B. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States)
2013-04-25
The first measurement of inelastic scattering of {sup 9}Li from deuterons at the ISAC facility is reported. The measured angular distribution for the first excited state confirms the nature of excitation to be an E2 transition. The quadrupole deformation parameter is extracted from an analysis of the angular distribution.
Wu, Xiang; Lee, Hyungseok; Bilsel, Osman; Zhang, Yuanwei; Li, Zhanjun; Chen, Teresa; Liu, Yi; Duan, Chunying; Shen, Jie; Punjabi, Amol; Han, Gang
2015-11-01
One of the key roadblocks in UCNP development is its extremely limited choices of excitation wavelengths. We report a generic design to program UCNPs to possess highly tunable dye characteristic excitation bands. Using such distinctive properties, we were able to develop a new excitation wavelength selective security imaging. This work unleashed the greater freedom of the excitation wavelengths of the upconversion nanoparticles and we believe it is a game-changer in the field and this method will enable numerous applications that are currently limited by existing UCNPs.One of the key roadblocks in UCNP development is its extremely limited choices of excitation wavelengths. We report a generic design to program UCNPs to possess highly tunable dye characteristic excitation bands. Using such distinctive properties, we were able to develop a new excitation wavelength selective security imaging. This work unleashed the greater freedom of the excitation wavelengths of the upconversion nanoparticles and we believe it is a game-changer in the field and this method will enable numerous applications that are currently limited by existing UCNPs. Electronic supplementary information (ESI) available: Experimental details for the synthesis, TEM, FTIR spectra, absorption and PL spectra. See DOI: 10.1039/c5nr05437k
Primary optical excitations and excited-state interaction energies in sexithiophene
Loi, MA; Martin, C; Chandrasekhar, HR; Chandrasekhar, M; Graupner, W; Garnier, F; Mura, A; Bongiovanni, G
2002-01-01
Based on a unique combination of angle-resolved transmission spectroscopy and transmission data at high pressure, we identify the primary photoexcitations and the relevant excited-state interaction energies in a sexithiophene crystal. Optical excitations include charge-transfer excitons and Davydov
Encryption in Chaotic Systems with Sinusoidal Excitations
Directory of Open Access Journals (Sweden)
G. Obregón-Pulido
2014-01-01
Full Text Available In this contribution an encryption method using a chaotic oscillator, excited by “n” sinusoidal signals, is presented. The chaotic oscillator is excited by a sum of “n” sinusoidal signals and a message. The objective is to encrypt such a message using the chaotic behavior and transmit it, and, as the chaotic system is perturbed by the sinusoidal signal, the transmission security could be increased due to the effect of such a perturbation. The procedure is based on the regulation theory and consider that the receiver knows the frequencies of the perturbing signal, with this considerations the algorithm estimates the excitation in such a way that the receiver can cancel out the perturbation and all the undesirable dynamics in order to produce only the message. In this way we consider that the security level is increased.
Charge-displacement analysis for excited states
Energy Technology Data Exchange (ETDEWEB)
Ronca, Enrico, E-mail: enrico@thch.unipg.it; Tarantelli, Francesco, E-mail: francesco.tarantelli@unipg.it [Istituto CNR di Scienze e Tecnologie Molecolari, via Elce di Sotto 8, I-06123 Perugia (Italy); Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, via Elce di Sotto 8, I-06123 Perugia (Italy); Pastore, Mariachiara, E-mail: chiara@thch.unipg.it; Belpassi, Leonardo; De Angelis, Filippo [Istituto CNR di Scienze e Tecnologie Molecolari, via Elce di Sotto 8, I-06123 Perugia (Italy); Angeli, Celestino; Cimiraglia, Renzo [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Ferrara, via Borsari 46, I-44100 Ferrara (Italy)
2014-02-07
We extend the Charge-Displacement (CD) analysis, already successfully employed to describe the nature of intermolecular interactions [L. Belpassi et al., J. Am. Chem. Soc. 132, 13046 (2010)] and various types of controversial chemical bonds [L. Belpassi et al., J. Am. Chem. Soc. 130, 1048 (2008); N. Salvi et al., Chem. Eur. J. 16, 7231 (2010)], to study the charge fluxes accompanying electron excitations, and in particular the all-important charge-transfer (CT) phenomena. We demonstrate the usefulness of the new approach through applications to exemplary excitations in a series of molecules, encompassing various typical situations from valence, to Rydberg, to CT excitations. The CD functions defined along various spatial directions provide a detailed and insightful quantitative picture of the electron displacements taking place.
Resonance Raman excitation profiles of lycopene
Hoskins, L. C.
1981-01-01
The resonance Raman spectrum of lycopene has been examined in acetone solvent and excitation profiles of the three fundamentals ν1, ν2, and ν3 have been determined. The excitation data and the visible spectrum have been analyzed using two-mode and three-mode vibrational models, with the two-mode model involving virtual states of ν1 and ν2 giving the best fit to the data. This mode mixing or Duskinsky effect was not observed for β-carotene. The single-mode and three-mode theories which have been used to explain the corresponding data for β-carotene are shown to be inconsistent with the experimental data of lycopene. Equations for calculating excitation profiles and visible spectra are given.
Diversity improves performance in excitable networks
Gollo, Leonardo L; Roberts, James A
2016-01-01
As few real systems comprise indistinguishable units, diversity is a hallmark of nature. Diversity among interacting units shapes properties of collective behavior such as synchronization and information transmission. However, the benefits of diversity on information processing at the edge of a phase transition, ordinarily assumed to emerge from identical elements, remain largely unexplored. Analyzing a general model of excitable systems with heterogeneous excitability, we find that diversity can greatly enhance optimal performance (by two orders of magnitude) when distinguishing incoming inputs. Heterogeneous systems possess a subset of specialized elements whose capability greatly exceeds that of the nonspecialized elements. Nonetheless, the behavior of the whole network can outperform all subgroups. We also find that diversity can yield multiple percolation, with performance optimized at tricriticality. Our results are robust in specific and more realistic neuronal systems comprising a combination of excit...
Adaptive transition rates in excitable membranes
Directory of Open Access Journals (Sweden)
Shimon Marom
2009-02-01
Full Text Available Adaptation of activity in excitable membranes occurs over a wide range of timescales. Standard computational approaches handle this wide temporal range in terms of multiple states and related reaction rates emanating from the complexity of ionic channels. The study described here takes a different (perhaps complementary approach, by interpreting ion channel kinetics in terms of population dynamics. I show that adaptation in excitable membranes is reducible to a simple Logistic-like equation in which the essential non-linearity is replaced by a feedback loop between the history of activation and an adaptive transition rate that is sensitive to a single dimension of the space of inactive states. This physiologically measurable dimension contributes to the stability of the system and serves as a powerful modulator of input-output relations that depends on the patterns of prior activity; an intrinsic scale free mechanism for cellular adaptation that emerges from the microscopic biophysical properties of ion channels of excitable membranes.
Nerve excitability in the rat forelimb
DEFF Research Database (Denmark)
Arnold, Ria; Moldovan, Mihai; Rosberg, Mette Romer;
2017-01-01
Background Nerve excitability testing by threshold-tracking is the only available method to study axonal ion channel function and membrane potential in the clinical setting. The measures are, however, indirect and the interpretation of neuropathic changes remains challenging. The same multiple...... measures of axonal excitability were adapted to further explore the pathophysiological changes in rodent disease models under pharmacologic and genetic manipulations. These studies are typically limited to the investigation of the “long nerves” such as the tail or the tibial nerves. New method We introduce...... a novel setup to explore the ulnar nerve excitability in rodents. We provide normative ulnar data in 11 adult female Long Evans rats under anaesthesia by comparison with tibial and caudal nerves. Additionally, these measures were repeated weekly on 3 occasions to determine the repeatability of these tests...
Double-excited resonant structure of photoionization
Institute of Scientific and Technical Information of China (English)
刘锦超; 杨向东; 王宗笠; 程延松
1997-01-01
The dominant diagrams were found in double-excited resonant structure of photoionization by using many-body perturbation theory.Based on the characteristics of these diagrams,the couple-equation method was improved,and the summation of specific classes of these diagrams is to an infinite order,and the resonant peaks with the widths are obtained first.The doubled-excited resonant structures (2p,3s)→(3p,np),(3p,nf),(3d,nd),(3d,ns) and (4s,ns) of the photoionization processes 2p→ks,kd are obtained.The photoionization with excitation process (2p,3s)→(3p,kp) was included in the calculations.The results of calculations are compared with the experimental data from 38.5 to 46.8 eV photon energies,which are in good agreement with the experiment.
Artificial Excitation of Schumann Resonance with HAARP
Streltsov, A. V.; Chang, C. L.
2014-12-01
We report results from the experiment aimed at the artificial excitation of extremely-low-frequency (ELF) electromagnetic waves with frequencies corresponding to the frequency of Schumann resonance (typically, 7.5 - 8.0 Hz frequency range). Electromagnetic waves with these frequencies can form a standing pattern inside the spherical cavity formed by the surface of the earth and the ionosphere. In the experiment the ELF waves were excited by heating the ionosphere with X-mode HF electromagnetic waves generated by the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. The experiment demonstrates that heating of the ionosphere can excite relatively large-amplitude electromagnetic waves with frequencies in the range of the Schumann resonance, when the ionosphere has a strong F-layer and an electric field greater than 5 mV/m is present in the E-region.
Pilot testing of a hydraulic bridge exciter
Directory of Open Access Journals (Sweden)
Andersson Andreas
2015-01-01
Full Text Available This paper describes the development of a hydraulic bridge exciter and its first pilot testing on a full scale railway bridge in service. The exciter is based on a hydraulic load cylinder with a capacity of 50 kN and is intended for controlled dynamic loading up to at least 50 Hz. The load is applied from underneath the bridge, enabling testing while the railway line is in service. The system is shown to produce constant load amplitude even at resonance. The exciter is used to experimentally determine frequency response functions at all sensor locations, which serve as valuable input for model updating and verification. An FE-model of the case study bridge has been developed that is in good agreement with the experimental results.
Exciting dynamic anapoles with electromagnetic doughnut pulses
Raybould, Tim; Fedotov, Vassili A.; Papasimakis, Nikitas; Youngs, Ian; Zheludev, Nikolay I.
2017-08-01
As was predicted in 1995 by Afanasiev and Stepanovsky, a superposition of electric and toroidal dipoles can lead to a non-trivial non-radiating charge current-configuration, the dynamic anapole. The dynamic anapoles were recently observed first in microwave metamaterials and then in dielectric nanodisks. However, spectroscopic studies of toroidal dipole and anapole excitations are challenging owing to their diminishing coupling to transverse electromagnetic waves. Here, we show that anapoles can be excited by electromagnetic Flying Doughnut (FD) pulses. First described by Helwarth and Nouchi in 1996, FD pulses (also known as "Flying Toroids") are space-time inseparable exact solutions to Maxwell's equations that have toroidal topology and propagate in free-space at the speed of light. We argue that FD pulses can be used as a diagnostic and spectroscopic tool for the dynamic anapole excitations in matter.
Collisional quenching of highly rotationally excited HF
Yang, Benhui; Forrey, R C; Stancil, P C; Balakrishnan, N
2015-01-01
Collisional excitation rate coefficients play an important role in the dynamics of energy transfer in the interstellar medium. In particular, accurate rotational excitation rates are needed to interpret microwave and infrared observations of the interstellar gas for nonlocal thermodynamic equilibrium line formation. Theoretical cross sections and rate coefficients for collisional deexcitation of rotationally excited HF in the vibrational ground state are reported. The quantum-mechanical close-coupling approach implemented in the nonreactive scattering code MOLSCAT was applied in the cross section and rate coefficient calculations on an accurate 2D HF-He potential energy surface. Estimates of rate coefficients for H and H$_2$ colliders were obtained from the HF-He collisional data with a reduced-potential scaling approach. The calculation of state-to-state rotational quenching cross sections for HF due to He with initial rotational levels up to $j=20$ were performed for kinetic energies from 10$^{-5}$ to 15000...
On the nature of an excited state
Blossier, Benoit
2016-01-01
In many lattice simulations with dynamical quarks, radial or orbital excitations of hadrons lie near multihadron thresholds: it makes the extraction of excited states properties more challenging and can introduce some systematics difficult to estimate without an explicit computation of correlators using interpolating fields strongly coupled to multihadronic states. In a recent study of the strong decay of the first radial excitation of the $B^*$ meson, this issue has been investigated and we have clues that a diquark interpolating field $\\bar{b} \\gamma^i q$ is very weakly coupled to a $B \\pi$ $P$-wave state while the situation is quite different if we consider an interpolating field of the kind $\\bar{b} \
Asymptotic Behavior of Excitable Cellular Automata
Durrett, R; Durrett, Richard; Griffeath, David
1993-01-01
Abstract: We study two families of excitable cellular automata known as the Greenberg-Hastings Model (GHM) and the Cyclic Cellular Automaton (CCA). Each family consists of local deterministic oscillating lattice dynamics, with parallel discrete-time updating, parametrized by the range of interaction, the "shape" of its neighbor set, threshold value for contact updating, and number of possible states per site. GHM and CCA are mathematically tractable prototypes for the spatially distributed periodic wave activity of so-called excitable media observed in diverse disciplines of experimental science. Earlier work by Fisch, Gravner, and Griffeath studied the ergodic behavior of these excitable cellular automata on Z^2, and identified two distinct (but closely-related) elaborate phase portraits as the parameters vary. In particular, they noted the emergence of asymptotic phase diagrams (and Euclidean dynamics) in a well-defined threshold-range scaling limit. In this study we present several rigorous results and som...
Population of highly excited intermediate resonance states by electron transfer and excitation
Energy Technology Data Exchange (ETDEWEB)
Schuch, R. (Manne Siegbahn Institute of Physics, S-104 05 Stockholm, Sweden (SE)); Justiniano, E. (Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353 (USA)); Schulz, M.; Datz, S.; Dittner, P.F.; Giese, J.P.; Krause, H.F.; Schoene, H.; Vane, R. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6377 (USA)); Shafroth, S. (Department of Physics, North Carolina University, Chapel Hill, North Carolina 27599-3255 (USA))
1991-05-01
Coincidences between two sulfur {ital K} x rays were detected from collisions of hydrogenlike S ions with H{sub 2} gas in the projectile energy range between 150 and 225 MeV. These {ital K} x rays are emitted in the decay of doubly excited states formed in the collisions via transfer and excitation. The excitation function for two coincident {ital K}{beta} transitions peaks at about 175 MeV, slightly above the expected {ital KMM} resonance energy for resonant transfer and excitation (RTE). This demonstrates the occurrence of {Delta}{ital N}{ge}2 transitions (i.e., {ital KMM} and higher resonances) in the RTE process. The cross sections for the population of the very highly excited states are higher than those predicted by theoretical calculations that use dielectronic recombination rates folded with the Compton profile for the bound electrons.
Electronic excitations in long polyenes revisited
Schmidt, Maximilian; Tavan, Paul
2012-03-01
We apply the valence shell model OM2 [W. Weber and W. Thiel, Theor. Chem. Acc. 103, 495, (2000), 10.1007/s002149900083] combined with multireference configuration interaction (MRCI) to compute the vertical excitation energies and transition dipole moments of the low-energy singlet excitations in the polyenes with 4 ⩽ N ⩽ 22π-electrons. We find that the OM2/MRCI descriptions closely resemble those of Pariser-Parr-Pople (PPP) π-electron models [P. Tavan and K. Schulten, Phys. Rev. B 36, 4337, (1987)], if equivalent MRCI procedures and regularly alternating model geometries are used. OM2/MRCI optimized geometries are shown to entail improved descriptions particularly for smaller polyenes (N ⩽ 12), for which sizeable deviations from the regular model geometries are found. With configuration interaction active spaces covering also the σ- in addition to the π-electrons, OM2/MRCI excitation energies turn out to become smaller by at most 0.35 eV for the ionic and 0.15 eV for the covalent excitations. The particle-hole (ph) symmetry, which in Pariser-Parr-Pople models arises from the zero-differential overlap approximation, is demonstrated to be only weakly broken in OM2 such that the oscillator strengths of the covalent 1B_u^- states, which artificially vanish in ph-symmetric models, are predicted to be very small. According to OM2/MRCI and experimental data the 1B_u^- state is the third excited singlet state for N 12, are caused by its restriction to at most doubly excited references.
Band excitation method applicable to scanning probe microscopy
Energy Technology Data Exchange (ETDEWEB)
Jesse, Stephen; Kalinin, Sergei V.
2017-01-03
Scanning probe microscopy may include a method for generating a band excitation (BE) signal and simultaneously exciting a probe at a plurality of frequencies within a predetermined frequency band based on the excitation signal. A response of the probe is measured across a subset of frequencies of the predetermined frequency band and the excitation signal is adjusted based on the measured response.
Computing Correct Truncated Excited State Wavefunctions
Bacalis, N C; Zang, J; Karaoulanis, D
2016-01-01
We demonstrate that, if a truncated expansion of a wave function is small, then the standard excited states computational method, of optimizing one root of a secular equation, may lead to an incorrect wave function - despite the correct energy according to the theorem of Hylleraas, Undheim and McDonald - whereas our proposed method [J. Comput. Meth. Sci. Eng. 8, 277 (2008)] (independent of orthogonality to lower lying approximants) leads to correct reliable small truncated wave functions. The demonstration is done in He excited states, using truncated series expansions in Hylleraas coordinates, as well as standard configuration-interaction truncated expansions.
Decay modes of the excited pseudoscalar glueball
Eshraim, Walaa I
2016-01-01
We study three different chiral Lagrangians that describe the two- and three-body decays of an excited pseudoscalar glueball, $J^{PC}=0^{*-+}$, into light mesons and charmonium states as well as into a scalar and pseudoscalar glueball. We compute the decay channels for an excited pseudoscalar glueball with a mass of $3.7$ GeV and consider a ground state pseudoscalar glueball of mass $2.6$ GeV, following predictions from lattice QCD simulations. These states and channels are in reach of the PANDA experiments at the upcoming FAIR facility experiment. We present the resulting decay branching ratios with a parameter-free prediction.
Excited random walks: results, methods, open problems
Kosygina, Elena
2012-01-01
We consider a class of self-interacting random walks in deterministic or random environments, known as excited random walks or cookie walks, on the d-dimensional integer lattice. The main purpose of this paper is two-fold: to give a survey of known results and some of the methods and to present several new results. The latter include functional limit theorems for transient one-dimensional excited random walks in bounded i.i.d. cookie environments as well as some zero-one laws. Several open problems are stated.
A Search for Excited Fermions at HERA
Adloff, C.; Andrieu, B.; Arkadov, V.; Astvatsatourov, A.; Ayyaz, I.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bassler, U.; Bate, P.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Benisch, T.; Berger, Christoph; Bernardi, G.; Berndt, T.; Bizot, J.C.; Borras, K.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruckner, W.; Bruel, P.; Bruncko, D.; Burger, J.; Busser, F.W.; Bunyatyan, A.; Burkhardt, H.; Burrage, A.; Buschhorn, G.; Campbell, A.J.; Cao, Jun; Carli, T.; Caron, S.; Chabert, E.; Clarke, D.; Clerbaux, B.; Collard, C.; Contreras, J.G.; Coughlan, J.A.; Cousinou, M.C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Davidsson, M.; Delcourt, B.; Delerue, N.; Demirchyan, R.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dixon, P.; Dodonov, V.; Dowell, J.D.; Droutskoi, A.; Duprel, C.; Eckerlin, Guenter; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Ferron, S.; Fleischer, M.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Foster, J.M.; Franke, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goodwin, C.; Grab, C.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Hadig, T.; Haidt, D.; Hajduk, L.; Haynes, W.J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Heremans, R.; Herrera, G.; Herynek, I.; Hilgers, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Hoprich, W.; Horisberger, R.; Hurling, S.; Ibbotson, M.; Issever, C .; Jacquet, M.; Jaffre, M.; Janauschek, L.; Jansen, D.M.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jones, M.A.S.; Jung, H.; Kastli, H.K.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnick, O.; Kaufmann, O.; Kausch, M.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kermiche, S.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Knies, G.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Kotelnikov, S.K.; Krasny, M.W.; Krehbiel, H.; Kroseberg, J.; Kruger, K.; Kupper, A.; Kuhr, T.; Kurca, T.; Kutuev, R.; Lachnit, W.; Lahmann, R.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Lebailly, E.; Lebedev, A.; Leissner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstroem, M.; Lobodzinska, E.; Lobodzinski, B.; Loktionova, N.; Lubimov, V.; Luders, S.; Luke, D.; Lytkin, L.; Magnussen, N.; Mahlke-Kruger, H.; Malden, N.; Malinovski, E.; Malinovski, I.; Maracek, R.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.U.; Martyniak, J.; Maxfield, S.J.; Mehta, A.; Meier, K.; Merkel, P.; Metlica, F.; Meyer, H.; Meyer, J.; Meyer, P.O.; Mikocki, S.; Milstead, D.; Mkrtchyan, T.; Mohr, R.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, Th.; Negri, I.; Nellen, G.; Newman, Paul R.; Nicholls, T.C.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Nunnemann, T.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Perez, E.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Potachnikova, I.; Povh, B.; Rabbertz, K.; Radel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Riess, S.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Royon, C.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, D.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Sedlak, K.; Sefkow, F.; Chekelian, V.; Sheviakov, I.; Shtarkov, L.N.; Siegmon, G.; Sievers, P.; Sirois, Y.; Sloan, T.; Smirnov, P.; Solochenko, V.; Solovev, Y.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Steinhart, J.; Stella, B.; Stellberger, A.; Stiewe, J.; Straumann, U.; Struczinski, W.; Swart, M.; Tasevsky, M.; Tchernyshov, V.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tobien, N.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; von Dombrowski, S.; Wacker, K.; Wallny, R.; Walter, T.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; Wegner, A.; Wengler, T.; Werner, M.; White, G.; Wiesand, S.; Wilksen, T.; Winde, M.; Winter, G.G.; Wissing, C.; Wobisch, M.; Wollatz, H.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; Zsembery, J.; zur Nedden, M.
2000-01-01
A search for excited fermions f^* of the first generation in e^+p scattering at the collider HERA is presented using H1 data with an integrated luminosity of 37 pb^(-1). All electroweak decays of excited fermions, f^* -> f gamma, f W, f Z are considered and all possible final states resulting from the Z or W hadronic decays or decays into leptons of the first two generations are taken into account. No evidence for f^* production is found. Mass dependent exclusion limits on cross-sections and on the ratio of coupling constants to the compositeness scale are derived.
Computing correct truncated excited state wavefunctions
Bacalis, N. C.; Xiong, Z.; Zang, J.; Karaoulanis, D.
2016-12-01
We demonstrate that, if a wave function's truncated expansion is small, then the standard excited states computational method, of optimizing one "root" of a secular equation, may lead to an incorrect wave function - despite the correct energy according to the theorem of Hylleraas, Undheim and McDonald - whereas our proposed method [J. Comput. Meth. Sci. Eng. 8, 277 (2008)] (independent of orthogonality to lower lying approximants) leads to correct reliable small truncated wave functions. The demonstration is done in He excited states, using truncated series expansions in Hylleraas coordinates, as well as standard configuration-interaction truncated expansions.
Electronic Excited States of Tungsten(0) Arylisocyanides
2015-01-01
W(CNAryl)_6 complexes containing 2,6-diisopropylphenyl isocyanide (CNdipp) are powerful photoreductants with strongly emissive long-lived excited states. These properties are enhanced upon appending another aryl ring, e.g., W(CNdippPh^(OMe)_2)_6; CNdippPh^(OMe)_2 = 4-(3,5-dimethoxyphenyl)-2,6-diisopropylphenylisocyanide (Sattler et al. J. Am. Chem. Soc. 2015, 137, 1198−1205). Electronic transitions and low-lying excited states of these complexes were investigated by time-dependent density fun...
Exciting Baryons: now and in the future
Pennington, M R
2011-01-01
This is the final talk of NSTAR2011 conference. It is not a summary talk, but rather a looking forward to what still needs to be done in excited baryon physics. In particular, we need to hone our tools connecting experimental inputs with QCD. At present we rely on models that often have doubtful connections with the underlying theory, and this needs to be dramatically improved, if we are to reach definitive conclusions about the relevant degrees of freedom of excited baryons. Conclusions that we want to have by NSTAR2021.
Laser Excited Fluorescence For Forensic Diagnostics
McKinney, Robert E.
1986-07-01
The application of laser excited fluorescence to the detection and identification of latent fingerprints was first accomplished ten years ago. The development of the technology has progressed rapidly with the introduction of commercial equipment by several manufacturers. Systems based on Argon-ion, Copper-vapor, and frequency-doubled Nd:YAG lasers are compared. The theoretical basis of detection by fluorescence is discussed along with the more useful techniques of dye staining. Other applications of the laser excited fluorescence in forensic investigation include gunshot residue analysis, serology, collection of trace evidence, and document examination.
Bogoliubov Excited States and the Lyth Bound
Aravind, Aditya; Paban, Sonia
2014-01-01
We show that Bogoliubov excited scalar and tensor modes do not alleviate Planckian evolution during inflation if one assumes that $r$ and the Bogoliubov coefficients are approximately scale invariant. We constrain the excitation parameter for the scalar fluctuations, $\\beta$, and tensor perturbations, $\\tilde{\\beta}$, by requiring that there be at least three decades of scale invariance in the scalar and tensor power spectrum. For the scalar fluctuations this is motivated by the observed nearly scale invariant scalar power spectrum. For the tensor fluctuations this assumption may be shown to be valid or invalid by future experiments.
Optimal Parametric Feedback Excitation of Nonlinear Oscillators
Braun, David J.
2016-01-01
An optimal parametric feedback excitation principle is sought, found, and investigated. The principle is shown to provide an adaptive resonance condition that enables unprecedentedly robust movement generation in a large class of oscillatory dynamical systems. Experimental demonstration of the theory is provided by a nonlinear electronic circuit that realizes self-adaptive parametric excitation without model information, signal processing, and control computation. The observed behavior dramatically differs from the one achievable using classical parametric modulation, which is fundamentally limited by uncertainties in model information and nonlinear effects inevitably present in real world applications.
Excited singlet states of "hairpin" polyenes
Froelich, Wolfgang; Dewey, Harry J.; Deger, Hans; Dick, Bernhard; Klingensmith, Kenneth A.; Puettmann, Wilhelm; Vogel, Emanuel; Hohlneicher, Georg; Michl, Josef
1983-01-01
The synthesis and UV-visible, polarized-fluorescence and MCD spectra of 6 U-shaped hairpin polyenes (e.g., I) are reported. Qual. arguments and results of p-electron calcns. permit the identification of 4 excited singlet states and their assignment to mixts. of singly and doubly excited configurations. The hairpin polyenes represent a link between the all-trans-polyenes on the 1 hand and the annulenes and acenes on the other; they have the topol. of the former and a geometry near that of the ...
Excited response of granular ores in vibrating field
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The dynamical theory was utilized to probe into the law of the excited response of granular ores generated by the exciting action of exciter and the influence of wave propagation in vibrating field. The exciter with double axes was presented as an example, and the principle of exciter and its mathematical expression of the excitation force were given. The granular ores have viscidity and damping speciality, on the basis of which the motion equation of excited response of ores was established and the approximate expression of mode-displacement by harmonic excitation and the steady effect solution of coordinate response were deduced. Utilizing the step-by-step integration method, the recursion relation matrix of displacement, velocity and acceleration of the excited response of ores were obtained, and the computational flow chart and a computational example were given. The results show that the excited response can change the dynamical character and the flowing characteristic of granular ores.
Relaxation channels of multi-photon excited xenon clusters
Energy Technology Data Exchange (ETDEWEB)
Serdobintsev, P. Yu.; Melnikov, A. S. [Institute of Nanobiotechnologies, Peter the Great St.Petersburg Polytechnic University, Saint Petersburg 195251 (Russian Federation); Department of Physics, St. Petersburg State University, Saint Petersburg 198904 (Russian Federation); Rakcheeva, L. P., E-mail: lida@nanobio.spbstu.ru; Murashov, S. V.; Khodorkovskii, M. A. [Institute of Nanobiotechnologies, Peter the Great St.Petersburg Polytechnic University, Saint Petersburg 195251 (Russian Federation); Lyubchik, S. [REQUIMTE, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica 2829-516 (Portugal); Timofeev, N. A.; Pastor, A. A. [Department of Physics, St. Petersburg State University, Saint Petersburg 198904 (Russian Federation)
2015-09-21
The relaxation processes of the xenon clusters subjected to multi-photon excitation by laser radiation with quantum energies significantly lower than the thresholds of excitation of atoms and ionization of clusters were studied. Results obtained by means of the photoelectron spectroscopy method showed that desorption processes of excited atoms play a significant role in the decay of two-photon excited xenon clusters. A number of excited states of xenon atoms formed during this process were discovered and identified.
PARAMETRIC EXCITATION IN A SELF-EXCITED THREE-DEGREES OF FREEDOM PROBLEM
Directory of Open Access Journals (Sweden)
SITI FATIMAH
2012-05-01
Full Text Available The efect of parametric excitation in self-excited has been investigated in two-degrees of freedom problems. The possibility of suppressing self-excited vibrationsby using parametric excitation and the dynamic behavior of those kind systems were discussed. In the this paper, we consider a system in three-degrees of freedom problem which by using a linear transformation the system becomes an Autoparametric. The system consists of a central mass and two external masses where those masses are conectedby springs with the same constant stiffness. The flow-generated self-excited force is actingon the external masses, it is represented by Rayleigh force. The variable stiffness isperiodically varying in time, represents a parametric excitation. It turns out that forcertain parameter ranges full vibration cancellation is possible. The analysis of linearcase of system shows that there are two conditions in order to obtain an interval ofthe parametric excitation. Using the averaging method the fully non-linear system is investigated producing as non-trivial solutions unstable periodic solutions. The behaviorof this unstable solution is studied in the full system.
Two-color temporal focusing multiphoton excitation imaging with tunable-wavelength excitation
Lien, Chi-Hsiang; Abrigo, Gerald; Chen, Pei-Hsuan; Chien, Fan-Ching
2017-02-01
Wavelength tunable temporal focusing multiphoton excitation microscopy (TFMPEM) is conducted to visualize optical sectioning images of multiple fluorophore-labeled specimens through the optimal two-photon excitation (TPE) of each type of fluorophore. The tunable range of excitation wavelength was determined by the groove density of the grating, the diffraction angle, the focal length of lenses, and the shifting distance of the first lens in the beam expander. Based on a consideration of the trade-off between the tunable-wavelength range and axial resolution of temporal focusing multiphoton excitation imaging, the presented system demonstrated a tunable-wavelength range from 770 to 920 nm using a diffraction grating with groove density of 830 lines/mm. TPE fluorescence imaging examination of a fluorescent thin film indicated that the width of the axial confined excitation was 3.0±0.7 μm and the shifting distance of the temporal focal plane was less than 0.95 μm within the presented wavelength tunable range. Fast different wavelength excitation and three-dimensionally rendered imaging of Hela cell mitochondria and cytoskeletons and mouse muscle fibers were demonstrated. Significantly, the proposed system can improve the quality of two-color TFMPEM images through different excitation wavelengths to obtain higher-quality fluorescent signals in multiple-fluorophore measurements.
Bifurcations in dynamical systems with parametric excitation
Fatimah, Siti
2002-01-01
This thesis is a collection of studies on coupled nonconservative oscillator systems which contain an oscillator with parametric excitation. The emphasis this study will, on the one hand, be on the bifurcations of the simple solutions such as fixed points and periodic orbits, and on the other hand o
Collective excitations of sup 3 He clusters
Energy Technology Data Exchange (ETDEWEB)
Serra, Ll.; Garcias, F. (Universidad de las Islas Baleares, Palma de Mallorca (Spain). Dept. de Fisica); Barranco, M. (Barcelona Univ. (Spain). Dept. de Estructura y Constituyentes de la Materia); Navarro, J. (Valencia Univ. (Spain). Dept. de Fisica Atomica, Molecular y Nuclear Consejo Superior de Investigaciones Cientificas, Valencia (Spain). Inst. de Fisica Corpuscular); Giai, V. (Paris-11 Univ., 91 - Orsay (France). Div. de Physique Theorique)
1991-01-01
Collective excitations of {sup 3}He clusters are studied by treating the cluster as a quantum liquid drop. We have used the Random-Phase Approximation sum rules technique within a Density Functional Formalism. Results for L=2 to 10 surface modes and the L=0 volume mode are presented. (orig.).
Lithium. Effects on excitable cell membranes
Ploeger, Egbert Johan
1974-01-01
LITHIUM: Effects on excitable cell membranes. Lithium salts have been used in the treatment of manic-depressive psychosis for many years but their mechanism of action is not well understood. Many workers assume that the action of lithium on catecholamine metabolism and/or on electrolyte distribution
Laser excitation of Antihydrogen in ALPHA
2016-01-01
Animation of how a trapped antihydrogen atom is excited by two photons from the 1S to the 2S state in antihydrogen, and further photo-ionised by a third foton. The first part of the movie shows how antihydrogen is made and captured in a magnetic minimum trap.
Clinical Comparison of Pulse and Chirp Excitation
DEFF Research Database (Denmark)
Pedersen, Morten Høgholm; Misaridis, T.; Jensen, Jørgen Arendt
2002-01-01
and short pulse excitation to simultaneously produce identical image sequences using both techniques. Nine healthy male volunteers were scanned in abdominal locations. All sequences were evaluated by 3 skilled medical doctors, blinded to each other and to the technique used. They assessed the depth (1...
New Logic Circuit with DC Parametric Excitation
Sugahara, Masanori; Kaneda, Hisayoshi
1982-12-01
It is shown that dc parametric excitation is possible in a circuit named JUDO, which is composed of two resistively-connected Josephson junctions. Simulation study proves that the circuit has large gain and properties suitable for the construction of small, high-speed logic circuits.
Excitation modes in non-axial nuclei
Energy Technology Data Exchange (ETDEWEB)
Leviatan, A.; Ginnochio, J.N.
1990-01-01
Excitation modes of non-axial quadrupole shapes are investigated in the framework of interacting boson models. Both {gamma}-unstable and {gamma}-rigid nuclear shapes are considered for systems with one type of boson as well as with proton-neutron bosons. 6 refs.
Motor axon excitability during Wallerian degeneration
DEFF Research Database (Denmark)
Moldovan, Mihai; Alvarez, Susana; Krarup, Christian
2008-01-01
, action potential propagation and structural integrity of the distal segment are maintained. The aim of this study was to investigate in vivo the changes in membrane function of motor axons during the 'latent' phase of Wallerian degeneration. Multiple indices of axonal excitability of the tibial nerve...
Inner-shell excitation spectroscopy of peroxides
Harding, K. L.; Kalirai, S.; Hayes, R.; Ju, V.; Cooper, G.; Hitchcock, A. P.; Thompson, M. R.
2015-01-01
O 1s inner-shell excitation spectra of a number of vapor phase molecules containing peroxide bonds - hydrogen peroxide (H2O2), di-t-butylperoxide ((BuOBu)-Bu-t-Bu-t), benzoyl peroxide, ((C6H5(CO)O)(2)), luperox-F [1,3(4)-bis(tertbutylperoxyisopropyl)benzene], and analogous, non-peroxide compounds -
Collective excitations of harmonically trapped ideal gases
Van Schaeybroeck, B.; Lazarides, A.
2009-01-01
We theoretically study the collective excitations of an ideal gas confined in an isotropic harmonic trap. We give an exact solution to the Boltzmann-Vlasov equation; as expected for a single-component system, the associated mode frequencies are integer multiples of the trapping frequency. We show
Stabilization of nonlinear excitations by disorder
DEFF Research Database (Denmark)
Christiansen, Peter Leth; Gaididei, Yuri Borisovich; Johansson, M.
1998-01-01
Using analytical and numerical techniques we analyze the static and dynamical properties of solitonlike excitations in the presence of parametric disorder in the one-dimensional nonlinear Schrodinger equation with a homogeneous power nonlinearity. Both the continuum and the discrete problem are i...
Localization of nonlinear excitations in curved waveguides
DEFF Research Database (Denmark)
Gaididei, Yu. B.; Christiansen, Peter Leth; Kevrekidis, P. G.;
2005-01-01
numerical simulations of the nonlinear problem and in this case localized excitations are found to persist. We found also interesting relaxational dynamics. Analogies of the present problem in context related to atomic physics and particularly to Bose–Einstein condensation are discussed....
Triple mode filters with coaxial excitation
Gerini, G.; Bustamante, F.D.; Guglielmi, M.
2004-01-01
In this paper we describe triple mode filters in a square waveguide with integrated coaxial input/output excitation. An important feature of the structure proposed is that it is easily amenable to an accurate full wave analysis. In addition to theory, a practical six pole filter with two transmissio
Magnetic Excitations from Stripes in Cuprate Superconductors
Tranquada, J. M.; Woo, H.; Perring, T. G.; Goka, H.; Gu, G. D.; Xu, G.; Fujita, M.; Yamada, K.
2004-03-01
While it is generally believed that antiferromagnetic spin excitations play a significant role in the pairing mechanism of copper-oxide superconductors [1], the nature of the magnetic excitations themselves remains a matter of controversy. Recent measurements of the dispersion of spin excitations in superconducting YBa_2Cu_3O_6+x (YBCO) have attracted much attention. Here we present the results of comprehensive inelastic neutron scattering measurements of the momentum- and energy-dependent spectra of the magnetic fluctuations in La_0.875Ba_0.125CuO_4, which exhibits inhomogeneous, charge-stripe order. We will also point out universalities and differences in the magnetic excitation spectra compared to related charge-stripe ordered compounds and high-temperature superconductors, including La_2-xSr_xNiO4 and YBCO. JMT, HW, GDG and GX are supported by U.S. Department of Energy contract # DE-AC02-98CH1088 [1] J. Orenstein and A. J. Millis, Science 288, 468 (2000).
Contour Line Portraits: Excited about Artistic Abilities
Neal, Kari Gertz
2012-01-01
In this article, the author describes a self-portrait project that encouraged students, boosted their self-confidence, and got them excited about their artistic abilities--while producing amazing results. This lesson effectively develops artistic ability by compelling students to see that drawing is quite simply breaking down objects into the…
The mean excitation energy of atomic ions
DEFF Research Database (Denmark)
Sauer, Stephan P. A.; Oddershede, Jens
2015-01-01
A method for calculation of the mean excitation energies of atomic ions is presented, making the calculation of the energy deposition of fast ions to plasmas, warm, dense matter, and complex biological systems possible. Results are reported to all ions of helium, lithium, carbon, neon, aluminum...
Nodal Variational Principle for Excited States
Zahariev, Federico; Levy, Mel
2016-01-01
It is proven that the exact excited-state wavefunction and energy may be obtained by minimizing the energy expectation value of a trial wave function that is constrained only to have the correct nodes of the state of interest. This excited-state nodal minimum principle has the advantage that it requires neither minimization with the con- straint of wavefunction orthogonality to all lower eigenstates nor the antisymmetry of the trial wavefunctions. It is also found that the minimization over the entire space can be partitioned into several in- terconnected minimizations within the individual nodal regions, and the exact excited-state energy may be obtained by a minimization in just one or several of these nodal regions. For the proofs of the the- orem, it is observed that the many-electron eigenfunction, restricted to a nodal region, is equivalent to a ground state wavefunction of one electron in a higher dimensional space; and an explicit excited-state energy variational expression is obtained by generalizing...
Spectroscopy of Optical Excitations in Carbon Nanotubes
Ma, Yingzhong
2006-03-01
Understanding the optical spectra and electronic excited state dynamics of carbon naotubes is important both for fundamental research and a wide variety of potential applications. In this presentation, we will report the results of a systematic study on semiconducting single-walled carbon nanotubes (SWNTs) obtained by utilizing complementary femtosecond spectroscopic techniques, including fluorescence up-conversion, frequency-resolved transient absorption, and three-pulse photon echo peakshift (3PEPS) spectroscopy. Our efforts have focused on optically selective detection of the spectra and dynamics associated with structurally distinct semiconducting SWNT species. Using individual nanotube enriched micelle-dispersed SWNT preparations, in combination with resonant excitation and detection, has enabled us to independently access selected species, such as the (8,3), (6,5), (7,5), (11,0), (7,6) and (9,5) nanotubes. We will discuss the following topics: (1) the excitonic nature of the elementary excitation and its unambiguous identification from direct determination of the exciton binding energy for a selected semiconducting nanotube, the (8,3) tube; (2) the spectroscopic and dynamical signatures of exciton-exciton annihilation and its predominant role in governing ultrafast excited state relaxation; (3) the annihilation-concomitant exciton dissociation and the spectroscopic and dynamic features of the resulting electron-hole continuum; (4) timescales characterizing the ultrafast thermalization processes. In addition, we will demonstrate the power of 3PEPS spectroscopy to elucidate the spectral properties and dynamics of SWNTs. This work was supported by the NSF.
Extracting excited mesons from the finite volume
Energy Technology Data Exchange (ETDEWEB)
Doring, Michael [George Washington Univ., Washington, DC (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2014-12-01
As quark masses come closer to their physical values in lattice simulations, finite volume effects dominate the level spectrum. Methods to extract excited mesons from the finite volume are discussed, like moving frames in the presence of coupled channels. Effective field theory can be used to stabilize the determination of the resonance spectrum.
Engage and Excite Students with Educational Games
Petsche, Jennifer
2011-01-01
Using educational games to learn or reinforce lessons engages students and turns a potentially boring subject into something exciting and desirable to know! Games offer teachers and parents a new way to grab students' attention so that they will retain information. Games have become a teaching tool, an invaluable resource for reaching students in…
Coherent acoustic excitation of cavity polaritons
DEFF Research Database (Denmark)
Poel, Mike van der; de Lima, M. M.; Hey, R.
and highly nonlinear optical response.Our sample consists of epitaxially grown GaAs/AlGaAs QWs located at the anti-node ofa high Q lambda cavity, which is resonant with the QW excitonic transition3. The SAWfield, which is excited by an interdigital transducer on the piezoelectric GaAs samplesurface...
Excitation of XUV radiation in solar flares
Emslie, A. Gordon
1992-01-01
The goal of the proposed research was to understand the means by which XUV radiation in solar flares is excited, and to use this radiation as diagnostics of the energy release and transport processes occurring in the flare. Significant progress in both of these areas, as described, was made.
Average excitation potentials of air and aluminium
Bogaardt, M.; Koudijs, B.
1951-01-01
By means of a graphical method the average excitation potential I may be derived from experimental data. Average values for Iair and IAl have been obtained. It is shown that in representing range/energy relations by means of Bethe's well known formula, I has to be taken as a continuously changing fu
Multipurpose exciter with low phase noise
Conroy, B.; Le, D.
1989-01-01
Results of an effort to develop a lower-cost exciter with high stability, low phase noise, and controllable phase and frequency for use in Deep Space Network and Goldstone Solar System Radar applications are discussed. Included is a discussion of the basic concept, test results, plans, and concerns.
Does intrinsic motivation enhance motor cortex excitability?
Radel, Rémi; Pjevac, Dusan; Davranche, Karen; d'Arripe-Longueville, Fabienne; Colson, Serge S; Lapole, Thomas; Gruet, Mathieu
2016-11-01
Intrinsic motivation (IM) is often viewed as a spontaneous tendency for action. Recent behavioral and neuroimaging evidence indicate that IM, in comparison to extrinsic motivation (EM), solicits the motor system. Accordingly, we tested whether IM leads to greater excitability of the motor cortex than EM. To test this hypothesis, we used two different tasks to induce the motivational orientation using either words representing each motivational orientation or pictures previously linked to each motivational orientation through associative learning. Single-pulse transcranial magnetic stimulation over the motor cortex was applied when viewing the stimuli. Electromyographic activity was recorded on the contracted first dorsal interosseous muscle. Two indexes of corticospinal excitability (the amplitude of motor-evoked potential and the length of cortical silent period) were obtained through unbiased automatic detection and analyzed using a mixed model that provided both statistical power and a high level of control over all important individual, task, and stimuli characteristics. Across the two tasks and the two indices of corticospinal excitability, the exposure to IM-related stimuli did not lead to a greater corticospinal excitability than EM-related stimuli or than stimuli with no motivational valence (ps > .20). While these results tend to dismiss the advantage of IM at activating the motor cortex, we suggest alternative hypotheses to explain this lack of effect, which deserves further research. © 2016 Society for Psychophysiological Research.
On the excitation of Goodwin's oscillations
Antonova, A. O.; Reznik, S. N.; Todorov, M. D.
2014-11-01
We consider the necessary condition for excitation of long-periodic Goodwin's oscillations and short-periodic sawtooth oscillations in the Goodwin model with fixed delay in the induced investment. Also, using the method of equivalent linearization we evaluate the amplitude of steady-state oscillation.
Saturated excitation of fluorescence to quantify excitation enhancement in aperture antennas.
Aouani, Heykel; Hostein, Richard; Mahboub, Oussama; Devaux, Eloïse; Rigneault, Hervé; Ebbesen, Thomas W; Wenger, Jérôme
2012-07-30
Fluorescence spectroscopy is widely used to probe the electromagnetic intensity amplification on optical antennas, yet measuring the excitation intensity amplification is a challenge, as the detected fluorescence signal is an intricate combination of excitation and emission. Here, we describe a novel approach to quantify the electromagnetic amplification in aperture antennas by taking advantage of the intrinsic non linear properties of the fluorescence process. Experimental measurements of the fundamental f and second harmonic 2f amplitudes of the fluorescence signal upon excitation modulation are used to quantify the electromagnetic intensity amplification with plasmonic aperture antennas.
Saturated excitation of Fluorescence to quantify excitation enhancement in aperture antennas
Aouani, Heykel
2012-07-23
Fluorescence spectroscopy is widely used to probe the electromagnetic intensity amplification on optical antennas, yet measuring the excitation intensity amplification is a challenge, as the detected fluorescence signal is an intricate combination of excitation and emission. Here, we describe a novel approach to quantify the electromagnetic amplification in aperture antennas by taking advantage of the intrinsic non linear properties of the fluorescence process. Experimental measurements of the fundamental f and second harmonic 2f amplitudes of the fluorescence signal upon excitation modulation are used to quantify the electromagnetic intensity amplification with plasmonic aperture antennas. © 2012 Optical Society of America.
Continuous Microwave Excitation of Excimer Lamps.
Hassal, Scott Bradley
1991-01-01
For decades, microwaves have been used to create gas discharges for many applications. This thesis deals with the use of microwaves to excite gas discharges for incoherent optical sources, with particular emphasis on excimer systems. In addition, microwave excitation of a gas laser is considered. A novel apparatus was designed and built to couple 2.45-GHz microwave radiation into a gas discharge. The microwave resonator is the essential part of this equipment, and a detailed discussion of its design and performance is given. The resonator is characterized both theoretically and experimentally in order to determine the coupling efficiency and peak electric-field strength. Specialized theory is developed in order to evaluate many parameters of a microwave-excited discharge. The phenomenon of skin effect is investigated quantitatively and expressions for the plasma frequency and electron density are developed in terms of collision frequency and observable parameters (e.g., skin depth). Expressions for peak electric-field strength, ionization coefficient and collisionless electron energy are also developed. The results of an extensive investigation of continuous-wave microwave-excited excimer fluorescence are reported. Rare-gas halide, homonuclear halogen and heteronuclear halogen systems are examined and the corresponding ultraviolet spectra are presented. Truly continuous excimer emission has been achieved (for the first time) on several transitions. For systems of particular interest (e.g. XeCl and KrCl), the effects of total pressures and gas composition on fluorescence output are investigated, and the appropriate spectra are presented. Finally, the potential operation of microwave-excited carbon dioxide and argon-ion gas lasers is investigated, and upper limits are deduced for the small-signal gain under various conditions.
Coulomb excitation of {sup 8}Li
Energy Technology Data Exchange (ETDEWEB)
Assuncao, Marlete; Britos, Tatiane Nassar [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Dept. de Ciencias Exatas e da Terra; Descouvemont, Pierre [Universite Libre de Bruxelles (ULB), Brussels (Belgium). Physique Nucleaire Theorique et Physique Mathematique; Lepine-Szily, Alinka; Lichtenthaler Filho, Rubens; Barioni, Adriana; Silva, Diego Medeiros da; Pereira, Dirceu; Mendes Junior, Djalma Rosa; Pires, Kelly Cristina Cezaretto; Gasques, Leandro Romero; Morais, Maria Carmen; Added, Nemitala; Neto Faria, Pedro; Rec, Rafael [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica. Dept. de Fisica Nuclear
2012-07-01
Full text: This work shows the Coulomb Excitation of {sup 8}Li on targets that have effectively behavior of Rutherford in angles and energies of interest for determining the value of the B(E2) electromagnetic transition. Theoretical aspects involved in this type of measure, known as COULEX [1], and some results in the literature [2-3] will be presented. Some problems with the targets and measurement system while performing an experiment on Coulomb Excitation of {sup 8}Li will be discussed: the energy resolution, background, possible contributions of the primary beam and also the excited states of the target near the region of elastic and inelastic peaks. They will be illustrated by measurements of the Coulomb Excitation of {sup 8}Li on targets of {sup 197}Au and {sup 208}Pb using the system RIBRAS(Brazilian Radioactive Ion Beam). In this case, the {sup 8}Li beam(T{sub 1/2} = 838 ms)is produced by {sup 9}Be({sup 7}Li;{sup 8} Li){sup 8}Be reaction from RIBRAS system which is installed at Instituto de Fisica of the Universidade de Sao Paulo. The primary {sup 7L}i beam is provided by Pelletron Accelerator. [1] K. Alder and A. Winther, Electromagnetic Excitation, North-Holland, New York, 1975; [2] P. Descouvemont and D. Baye, Phys. Letts. B 292, 235-238, 1992; [3] J. A. Brown, F. D. Becchetti, J. W. Jaenecke, K, Ashktorab, and D. A. Roberts, J. J. Kolata, R. J. Smith, and K. Lamkin, R. E. Warner, Phys. Rev. Letts., 66, 19, 1991; [4] R. J. Smith, J. J Kolata, K. Lamkin and A. Morsard, F. D. Becchetti, J. A. Brown, W. Z. Liu, J. W. Jaenecke, and D. A. Roberts, R. E. Warner, Phys. Rev. C, 43, 5, 1991. (author)
Cascadable excitability in optically injected microdisks
Van Vaerenbergh, Thomas; Alexander, Koen; Fiers, Martin; Mechet, Pauline; Dambre, Joni; Bienstman, Peter
2014-05-01
All-optical spiking neural networks would allow high speed parallelized processing of time-encoded information, using the same energy efficient computational principles as our brain. As the neurons in these networks need to be able to process pulse trains, they should be excitable. Using simulations, we demonstrate Class 1 excitability in optically injected microdisk lasers, and propose a cascadable optical spiking neuron design. The neuron has a clear threshold and an integrating behavior. In addition, we show that the optical phase of the input pulses can be used to create inhibitory, as well as excitatory perturbations. Furthermore, we incorporate our optical neuron design in a topology that allows a disk to react on excitations from other disks. Phase tuning of the intermediate connections allows to control the disk response. Additionally, we investigate the sensitivity of the disk circuit to deviations in driving current and locking signal wavelength detuning. Using state-of-the-art fabrication techniques for microdisk laser, the standard deviation of the lasing wavelength is still about one order of magnitude too large. Finally, as the dynamical behavior of the microdisks is identical to the behavior in Semiconductor Ring Lasers (SRL), we compare the excitability mechanism due to optically injection with the previously proposed excitability due to asymmetry in the intermodal coupling in SRLs, as the latter mechanism can also be induced in disks due to, e.g., asymmetry in the external reaction. In both cases, the symmetry between the two counter-propagating modes of the cavity needs to be broken to prevent switching to the other mode, and allow the system to relax to its initial state after a perturbation. However, the asymmetry due to optical injection results in an integrating spiking neuron, whereas the asymmetry in the intermodal coupling is known to result in a resonating spiking neuron.
Selective serotonergic excitation of callosal projection neurons
Directory of Open Access Journals (Sweden)
Daniel eAvesar
2012-03-01
Full Text Available Serotonin (5-HT acting as a neurotransmitter in the cerebral cortex is critical for cognitive function, yet how 5-HT regulates information processing in cortical circuits is not well understood. We tested the serotonergic responsiveness of layer 5 pyramidal neurons (L5PNs of the mouse medial prefrontal cortex (mPFC, and found 3 distinct response types: long-lasting 5-HT1A (1A receptor-dependent inhibitory responses (84% of L5PNs, 5-HT2A (2A receptor-dependent excitatory responses (9%, and biphasic responses in which 2A-dependent excitation followed brief inhibition (5%. Relative to 5-HT-inhibited neurons, those excited by 5-HT had physiological properties characteristic of callosal/commissural (COM neurons that project to the contralateral cortex. We tested whether serotonergic responses in cortical pyramidal neurons are correlated with their axonal projection pattern using retrograde fluorescent labeling of COM and corticopontine-projecting (CPn neurons. 5-HT generated excitatory or biphasic responses in all 5-HT-responsive layer 5 COM neurons. Conversely, CPn neurons were universally inhibited by 5-HT. Serotonergic excitation of COM neurons was blocked by the 2A antagonist MDL 11939, while serotonergic inhibition of CPn neurons was blocked by the 1A antagonist WAY 100635, confirming a role for these two receptor subtypes in regulating pyramidal neuron activity. Selective serotonergic excitation of COM neurons was not layer-specific, as COM neurons in layer 2/3 were also selectively excited by 5-HT relative to their non-labeled pyramidal neuron neighbors. Because neocortical 2A receptors are implicated in the etiology and pathophysiology of schizophrenia, we propose that COM neurons may represent a novel cellular target for intervention in psychiatric disease.
Energy Technology Data Exchange (ETDEWEB)
Copan, Andreas V.; Wiens, Avery E.; Nowara, Ewa M.; Schaefer, Henry F.; Agarwal, Jay, E-mail: jagarwal@uga.edu [Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602 (United States)
2015-02-07
Peroxyacetyl radical [CH{sub 3}C(O)O{sub 2}] is among the most abundant peroxy radicals in the atmosphere and is involved in OH-radical recycling along with peroxyacetyl nitrate formation. Herein, the ground (X{sup ~}) and first (A{sup ~}) excited state surfaces of cis and trans peroxyacetyl radical are characterized using high-level ab initio methods. Geometries, anharmonic vibrational frequencies, and adiabatic excitation energies extrapolated to the complete basis-set limit are reported from computations with coupled-cluster theory. Excitation of the trans conformer is found to induce a symmetry-breaking conformational change due to second-order Jahn-Teller interactions with higher-lying excited states. Additional benchmark computations are provided to aid future theoretical work on peroxy radicals.
Burdzinski, Gotard T; Middleton, Chris T; Gustafson, Terry L; Platz, Matthew S
2006-11-22
Photolysis of phenyl and o-biphenylyl azide (at 270 nm) releases vibrationally excited singlet nitrene which isomerizes to the corresponding hot 1,2-didehydroazepine at a rate competitive with thermal relaxation. Using ultrafast vibrational spectroscopy we observe the formation of vibrationally excited 1,2-4,6-azacycloheptatetraene (1,2-didehydroazepine) in picoseconds following photolysis of phenyl azide in chloroform and o-biphenylyl azide in acetonitrile at ambient temperature.
Directory of Open Access Journals (Sweden)
Liu Tao
2017-01-01
Full Text Available This work is focused on the topology optimization of structures that are subjected to harmonic force excitation with prescribed frequency and amplitude. As an important objective of such a design problem, the natural resonance frequency of the structure is driven far away from the prescribed excitation frequency for the purpose of avoiding resonance and reducing the vibration level. Therefore when the excitation frequency is higher than the natural resonance frequency of the structure, the natural resonance frequency will decrease, then the optimum topology configuration will be distorted with large amount of gray elements. A MAC (Modal Assurance Criteria based excitation frequency increasing method is proposed to obtain a desired configuration. MAC is adopted here to track the natural resonance frequency which can provide the baseline reference for the current excitation frequency during the optimum iterative procedure. Then the excitation frequency increases progressively up to its originally prescribed value. By means of numerical examples, the proposed formulation can generate effective topology configurations which can avoid resonance.
Dynamics of excited m-dichlorobenzene
Institute of Scientific and Technical Information of China (English)
YUAN Liwei; WANG Yanqiu; WANG Li; BAI Jiling; HE Guozhong
2004-01-01
Dynamics of excited m-dichlorobenzene is investigated in real time by femtosecond pump-probe method, combined with time-of-flight mass spectrometric detection in a supersonic molecular beam. The yields of the parent ion and daughter ion C6H4Cl+ are examined as a function of the delay between the 270 and 810 nm femtosecond laser pulses, respectively. The lifetime of the first singlet excited state S1 of m-dichlorobenzene is measured. The origin of this daughter ion C6H4Cl+ is discussed. The ladder mechanism is proposed to form the fragment ion.In addition, our experimental results exhibit a rapid damped sinusoidal oscillation over intermediate time delays, which is due to quantum beat effects.
Quasiparticle excitations in relativistic quantum field theory
Arteaga, Daniel
2008-01-01
We analyze the particle-like excitations arising in relativistic field theories in states different than the vacuum. The basic properties characterizing the quasiparticle propagation are studied using two different complementary methods. First we introduce a frequency-based approach, wherein the quasiparticle properties are deduced from the spectral analysis of the two-point propagators. Second, we put forward a real-time approach, wherein the quantum state corresponding to the quasiparticle excitation is explicitly constructed, and the time-evolution is followed. Both methods lead to the same result: the energy and decay rate of the quasiparticles are determined by the real and imaginary parts of the retarded self-energy respectively. Both approaches are compared, on the one hand, with the standard field-theoretic analysis of particles in the vacuum and, on the other hand, with the mean-field-based techniques in general backgrounds.
The Tongue as an Excitable Medium
Seiden, Gabriel
2014-01-01
Geographic tongue (GT) is a benign condition affecting approximately 2% of the population, whereby the papillae covering the upper part of the tongue are lost due to a slowly expanding inflammation. The resultant dynamical appearance of the tongue has striking similarities with well known phenomena observed in excitable media, such as forest fires, cardiac dynamics and chemically-driven reaction-diffusion systems. Here we explore the dynamics associated with GT from a dynamical systems perspective, utilizing cellular automata simulations. We emphasize similarities with other excitable systems as well as unique features observed in GT. Our results shed light on the evolution of the inflammation and contribute to the classification of the severity of the condition, based on the characteristic patterns observed in GT patients.
Condensate of excitations in moving superfluids
Kolomeitsev, E E
2016-01-01
A possibility of the condensation of excitations with a non-zero momentum in rectilinearly moving and rotating superfluid bosonic and fermionic (with Cooper pairing) media is considered in terms of a phenomenological order-parameter functional at zero and non-zero temperature. The results might be applicable to the description of bosonic systems like superfluid $^4$He, ultracold atomic Bose gases, charged pion and kaon condensates in rotating neutron stars, and various superconducting fermionic systems with pairing, like proton and color-superconducting components in compact stars, metallic superconductors, and neutral fermionic systems with pairing, like the neutron component in compact stars and ultracold atomic Fermi gases. Order parameters of the "mother" condensate in the superfluid and the new condensate of excitations, corresponding energy gains, critical temperatures and critical velocities are found.
Inelastic collisions of excited lithium molecules
Rosenberry, Mark; Marhatta, Ramesh; Stewart, Brian
2010-03-01
Energy transfer and reactions during molecular collisions are fundamental processes in astronomy and chemistry. The H2 + H system has been well studied, and theoretical calculations are now becoming feasible for an excited lithium dimer colliding with a ground state lithium atom, increasing interest in corresponding experimental measurements. Our laboratory observes laser-induced fluorescence spectra from lithium vapor in a heat pipe oven. Our recent switch from a modest diode laser to a pulsed dye laser gives us new access to a variety of highly excited molecular states. Here we report our progress in measuring absolute level-to-level rate constants and collision-induced dissociation for molecular states of this system.
Excitation and Characterization of Chladni Plate Patterns
Bourke, Shannon; Behringer, Ernest
2011-04-01
When a thin metal plate with a small amount of sand on it is made to vibrate, aesthetically pleasing sand patterns can form along the nodal lines of the plate. These symmetric patterns are called Chladni Patterns. Students taking PHY 101 Physical Science in the Arts at Eastern Michigan University create these patterns by pulling a violin bow across the edge of a plate, or by using a mechanical oscillator to drive the center of a plate. These two methods only allow a small subset of all possible points on the plate to be excited. We designed and built an electronic device that allows its user to excite the plate at any point. We present patterns created with this electronic device and other methods, and describe ways to model the observed patterns.
White noise excitation of road vehicle structures
Indian Academy of Sciences (India)
Werner Schiehlen
2006-08-01
Heave and pitch motions of road vehicle structures affect the comfort and the safety of passengers. Excitation of these vertical vibrations is due to road surface roughness. Road vehicle structures are modelled as mechanical systems characterized by their inertia, damping and stiffness, and represented as state equations. This paper deals with the inﬂuence of random road proﬁles on the vertical dynamics of road vehicles characterized by stochastic processes. Switching from road proﬁle displacement to road proﬁle velocity results in white noise excitation facilitating mathematical analysis. Some fundamentals of power spectral density analysis and covariance analysis are reviewed. A quarter car model is used to show the advantages of the covariance analysis resulting immediately in standard variations characterizing the vehicle’s performance.
On light baryons and their excitations
Eichmann, Gernot; Sanchis-Alepuz, Helios
2016-01-01
We study ground states and excitations of light octet and decuplet baryons within the framework of Dyson-Schwinger and Faddeev equations. We improve upon similar approaches by explicitly taking into account the momentum-dependent dynamics of the quark-gluon interaction that leads to dynamical chiral symmetry breaking. We perform calculations in both the three-body Faddeev framework and the quark-diquark approximation in order to assess the impact of the latter on the spectrum. Our results indicate that both approaches agree well with each other. The resulting spectra furthermore agree one-to-one with experiment, provided well-known deficiencies of the rainbow-ladder approximation are compensated for. We also discuss the mass evolution of the Roper and the excited Delta with varying pion mass and analyse the internal structure in terms of their partial wave decompositions.
Multiflavour excited mesons from the fifth dimension
Paredes, A; Paredes, Angel; Talavera, Pere
2004-01-01
We study the Regge trajectories and the quark-antiquark energy in excited hadrons composed by different dynamical mass constituents via the gauge/string correspondence. First we exemplify the procedure in a supersymmetric system, D3-D7, in the extremal case. Afterwards we discuss the model dual to large-Nc QCD, D4-D6 system. In the latter case we find the field theory expected gross features of vector like theories: the spectrum resembles that of heavy quarkonia and the Chew-Frautschi plot of the singlet and first excited states is in qualitative agreement with those of lattice QCD. We stress the salient points of including different constituents masses.
Decay modes of the excited pseudoscalar glueball
Eshraim, Walaa I.; Schramm, Stefan
2017-01-01
We study three different chiral Lagrangians that describe the two- and three-body decays of an excited pseudoscalar glueball, JP C=0*-+ , into light mesons and charmonium states as well as into a scalar and pseudoscalar glueball. We compute the decay channels for an excited pseudoscalar glueball with a mass of 3.7 GeV and consider a ground-state pseudoscalar glueball of mass 2.6 GeV, following predictions from lattice QCD simulations. These states and channels are in reach of the ongoing BESIII experiment and the PANDA experiments at the upcoming FAIR facility experiment. We present the resulting decay branching ratios with a parameter-free prediction.
Springing response due to bidirectional wave excitation
DEFF Research Database (Denmark)
Vidic-Perunovic, Jelena
2005-01-01
theories deal with the unidirectional wave excitation. This is quite standard. The problem is how to include more than one directional wave systems described by a wave spectrum with arbitrary heading. The main objective of the present work has been to account for the additional second-order springing...... a discrepancy with full-scale measurements exists, but worse is that no tendency in the measurement trend is captured. An important source of high frequency springing excitation is undoubtedly missing. The full-scale measurements that are presented in the thesis and have been used for the validation are unique...... because, to the author's knowledge, this is the first time that the wave data were collected simultaneously with stress records on the deck of the ship. This is highly appreciated because one can use the precise input and not only the most probable sea state statistics. The actual picture of the sea waves...
Nuclear Excitations by Antiprotons and Antiprotonic Atoms
2002-01-01
The proposal aims at the investigation of nuclear excitations following the absorption and annihilation of stopped antiprotons in heavier nuclei and at the same time at the study of the properties of antiprotonic atoms. The experimental arrangement will consist of a scintillation counter telescope for the low momentum antiproton beam from LEAR, a beam degrader, a pion multiplicity counter, a monoisotopic target and Ge detectors for radiation and charged particles. The data are stored by an on-line computer.\\\\ \\\\ The Ge detectors register antiprotonic x-rays and nuclear @g-rays which are used to identify the residual nucleus and its excitation and spin state. Coincidences between the two detectors will indicate from which quantum state the antiprotons are absorbed and to which nuclear states the various reactions are leading. The measured pion multiplicity characterizes the annihilation process. Ge&hyphn. and Si-telescopes identify charged particles and determine their energies.\\\\ \\\\ The experiment will gi...
Edge excitations in fractional Chern insulators
Luo, Wei-Wei; Chen, Wen-Chao; Wang, Yi-Fei; Gong, Chang-De
2013-10-01
Recent theoretical papers have demonstrated the realization of fractional quantum anomalous Hall states (also called fractional Chern insulators) in topological flat band lattice models without an external magnetic field. Such newly proposed lattice systems play a vital role in obtaining a large class of fractional topological phases. Here we report the exact numerical studies of edge excitations for such systems in a disk geometry loaded with hard-core bosons, which will serve as a more viable experimental probe for such topologically ordered states. We find convincing numerical evidence of a series of edge excitations characterized by the chiral Luttinger liquid theory for the bosonic fractional Chern insulators in both the honeycomb disk Haldane model and the kagome-lattice disk model. We further verify these current-carrying chiral edge states by inserting a central flux to test their compressibility.
Effects of aging on motor cortex excitability.
Oliviero, A; Profice, P; Tonali, P A; Pilato, F; Saturno, E; Dileone, M; Ranieri, F; Di Lazzaro, V
2006-05-01
To determine whether aging is associated with changes in excitability of the cerebral cortex, we evaluated the excitability of the motor cortex with transcranial magnetic stimulation (TMS). We compared TMS related measures obtained in a group of young people with those of a group of old people. Motor evoked potential (MEP) amplitude was significantly smaller in older than in younger controls (1.3+/-0.8 mV versus 2.7+/-1.1 mV; p<0.0071). Mean cortical silent period (CSP) duration was shorter in older than in younger controls (87+/-29 ms versus 147+/-39 ms; p<0.0071). SP duration/MEP amplitude ratios were similar in both groups. Our results are consistent with an impaired efficiency of some intracortical circuits in old age.
Excited-state relaxation of some aminoquinolines
Directory of Open Access Journals (Sweden)
2006-01-01
Full Text Available The absorption and fluorescence spectra, fluorescence quantum yields and lifetimes, and fluorescence rate constants ( k f of 2-amino-3-( 2 ′ -benzoxazolylquinoline (I, 2-amino-3-( 2 ′ -benzothiazolylquinoline (II, 2-amino-3-( 2 ′ -methoxybenzothiazolyl-quinoline (III, 2-amino-3-( 2 ′ -benzothiazolylbenzoquinoline (IV at different temperatures have been measured. The shortwavelength shift of fluorescence spectra of compounds studied (23–49 nm in ethanol as the temperature decreases (the solvent viscosity increases points out that the excited-state relaxation process takes place. The rate of this process depends essentially on the solvent viscosity, but not the solvent polarity. The essential increasing of fluorescence rate constant k f (up to about 7 times as the solvent viscosity increases proves the existence of excited-state structural relaxation consisting in the mutual internal rotation of molecular fragments of aminoquinolines studied, followed by the solvent orientational relaxation.
Edge Magnon Excitation in Spin Dimer Systems
Sakaguchi, Ryo; Matsumoto, Masashige
2016-10-01
Magnetic excitation in a spin dimer system on a bilayer honeycomb lattice is investigated in the presence of a zigzag edge, where disordered and ordered phases can be controlled by a quantum phase transition. In analogy with the case of graphene with a zigzag edge, a flat edge magnon mode appears in the disordered phase. In an ordered phase, a finite magnetic moment generates a mean-field potential to the magnon. Since the potential is nonuniform on the edge and bulk sites, it affects the excitation, and the dispersion of the edge mode deviates from the flat shape. We investigate how the edge magnon mode evolves when the phase changes through the quantum phase transition and discuss the similarities to ordered spin systems on a monolayer honeycomb lattice.
Crystal growth as an excitable medium.
Cartwright, Julyan H E; Checa, Antonio G; Escribano, Bruno; Sainz-Díaz, C Ignacio
2012-06-28
Crystal growth has been widely studied for many years, and, since the pioneering work of Burton, Cabrera and Frank, spirals and target patterns on the crystal surface have been understood as forms of tangential crystal growth mediated by defects and by two-dimensional nucleation. Similar spirals and target patterns are ubiquitous in physical systems describable as excitable media. Here, we demonstrate that this is not merely a superficial resemblance, that the physics of crystal growth can be set within the framework of an excitable medium, and that appreciating this correspondence may prove useful to both fields. Apart from solid crystals, we discuss how our model applies to the biomaterial nacre, formed by layer growth of a biological liquid crystal.
FEEDBACK CONTROL OPTIMIZATION FOR SEISMICALLY EXCITED BUILDINGS
Institute of Scientific and Technical Information of China (English)
Xueping Li; Zuguang Ying
2007-01-01
A feedback control optimization method of partially observable linear structures via stationary response is proposed and analyzed with linear building structures equipped with control devices and sensors. First, the partially observable control problem of the structure under horizontal ground acceleration excitation is converted into a completely observable control problem. Then the It(o) stochastic differential equations of the system are derived based on the stochastic averaging method for quasi-integrable Hamiltonian systems and the stationary solution to the Fokker-Plank-Kolmogorov (FPK) equation associated with the It(o) equations is obtained.The performance index in terms of the mean system energy and mean square control force is established and the optimal control force is obtained by minimizing the performance index. Finally, the numerical results for a three-story building structure model under El Centro, Hachinohe,Northridge and Kobe earthquake excitations are given to illustrate the application and the effectiveness of the proposed method.
Nanowire Plasmon Excitation by Adiabatic Mode Transformation
Verhagen, Ewold; Spasenović, Marko; Polman, Albert; Kuipers, L. (Kobus)
2009-05-01
We show with both experiment and calculation that highly confined surface plasmon polaritons can be efficiently excited on metallic nanowires through the process of mode transformation. One specific mode in a metallic waveguide is identified that adiabatically transforms to the confined nanowire mode as the waveguide width is reduced. Phase- and polarization-sensitive near-field investigation reveals the characteristic antisymmetric polarization nature of the mode and explains the coupling mechanism.
Dynamical analysis of highly excited molecular spectra
Energy Technology Data Exchange (ETDEWEB)
Kellman, M.E. [Univ. of Oregon, Eugene (United States)
1993-12-01
The goal of this program is new methods for analysis of spectra and dynamics of highly excited vibrational states of molecules. In these systems, strong mode coupling and anharmonicity give rise to complicated classical dynamics, and make the simple normal modes analysis unsatisfactory. New methods of spectral analysis, pattern recognition, and assignment are sought using techniques of nonlinear dynamics including bifurcation theory, phase space classification, and quantization of phase space structures. The emphasis is chaotic systems and systems with many degrees of freedom.
Phase dependent interference effects on atomic excitation
Jha, Pankaj K; Sautenkov, Vladimir A; Rostovtsev, Yuri V; Scully, Marlan O
2011-01-01
We present an experimental and theoretical study of phase-dependent interference effects in multi-photon excitation under bichromatic radio-frequency (rf) field. Using an intense rf pulse, we study the interference between the three-photon and one-photon transition between the Zeeman sub-levels of the ground state of $^{87}$Rb that allows us to determine the carrier-envelope phase of the fields even for long pulses.
Rearrangements in ground and excited states
de Mayo, Paul
1980-01-01
Rearrangements in Ground and Excited States, Volume 2 covers essays on the theoretical approach of rearrangements; the rearrangements involving boron; and the molecular rearrangements of organosilicon compounds. The book also includes essays on the polytopal rearrangement at phosphorus; the rearrangement in coordination complexes; and the reversible thermal intramolecular rearrangements of metal carbonyls. Chemists and people involved in the study of rearrangements will find the book invaluable.
Self-excitation of space charge waves
DEFF Research Database (Denmark)
Lyuksyutov, Sergei; Buchhave, Preben; Vasnetsov, Mikhail
1997-01-01
We report a direct observation of space charge waves in photorefractive crystals with point group 23 (sillenites) based on their penetration into an area with uniform light illumination. It is shown experimentally that the quality factor of the waves increases substantially with respect to what...... current theory predicts [B. Sturman el al., Appl. Phys. A 55, 235 (1992)]. This results in the appearance of strong spontaneous beams caused by space charge wave self-excitation....
Magnetic Excitations and Magnetic Ordering in Praseodymium
DEFF Research Database (Denmark)
Houmann, Jens Christian Gylden; Chapellier, M.; Mackintosh, A. R.;
1975-01-01
The dispersion relations for magnetic excitons propagating on the hexagonal sites of double-hcp Pr provide clear evidence for a pronounced anisotropy in the exchange. The energy of the excitations decreases rapidly as the temperature is lowered, but becomes almost constant below about 7 K......, in agreement with a random-phase-approximation calculation. No evidence of magnetic ordering has been observed above 0.4 K, although the exchange is close to the critical value necessary for an antiferromagnetic state....
STIRAP on helium: Excitation to Rydberg states
Yuan, Deqian
Research in optically induced transitions between dierent atomic levels has a long history. For transitions between states driven by a coherent optical eld, the theoretical eciency could be ideally high as 100% but there could be many factors preventing this. In the three state helium atom excitation process, i.e. 23S→33P→nL , the stimulated emission from intermediate state makes it hard to achieve ecient population transfer to the nal state through an intuitive excitation order. One technique to achieve a higher eciency is Stimulated Raman Adiabatic Passage (STIRAP) which is being studied and under research in our lab. Unlike traditional three level excitation processes, STIRAP actually uses a counter intuitive pulsed laser beams timing arrangement. The excitation objects are metastable helium atoms traveling in a vacuum system with a longitudinal velocity of ~ 1070 m/s. We are using a 389 nm UV laser to connect the 23S and the 33P state and a frequency tunable ~790 nm IR laser to connect the 33P state and the dierent Rydberg states. A third 1083 nm wavelength laser beam drives the 23S → 23P transition to transversely separate the residual metastable atoms and the Rydberg atoms for eciency measurements. The data is taken by a stainless steel detector in the vacuum system. As the Rydberg atoms will get ionized by blackbody radiation under room temperature, we can utilize this for their detection. An ion detector sitting on the eld plate is capable to collect the ion signals of the Rydberg atoms for detection. So far the whole system has not been ready for data collection and measurement, so here we are using data and results from previous theses for discussions. The highest transition frequency that has ever been achieved in our lab is around 70% after corrections.
Contemporary continuum QCD approaches to excited hadrons
Directory of Open Access Journals (Sweden)
El-Bennich Bruno
2016-01-01
Full Text Available Amongst the bound states produced by the strong interaction, radially excited meson and nucleon states offer an important phenomenological window into the long-range behavior of the coupling constant in Quantum Chromodynamics. We here report on some technical details related to the computation of the bound state’s eigenvalue spectrum in the framework of Bethe-Salpeter and Faddeev equations.
Photocycloaddition of anthracene to excited C-60
Energy Technology Data Exchange (ETDEWEB)
Gol`dshleger, N.F.; Denisov, N.N.; Lobach, A.S. [and others
1995-02-01
The ability to participate in photochemical cycloaddition reactions is characteristic feature of chromophores with a carbon double bond. In this work, the authors demonstrate the formation of an adduct by cycloaddition of anthracene to the triplet-excited C-60 fullerene under anaerobic conditions, which provides a straight forward way to synthesize new derivatives of C-60 fullerenes. Reaction methods, conditions, and mechanisms are included along with the characterization of the fullerene derivative with IR, MS, and NMR methods.
TXRF spectrometry at ion beam excitation
Egorov, V.; Egorov, E.; Afanas’ef, M.
2017-02-01
The work presents short discussion of TXRF and PIXE methods peculiarities. Taking into account of these peculiarities we elaborate the experimental scheme for TXRF measurements at ion beam excitation of characteristical fluorescence. The scheme is built on base of the planar X-ray waveguide-resonator with specific design. Features of the new experimental method and possibilities of Sokol-3 ion beam analytical complex were used for the method application in real measurements.
Synchronized Firing in Coupled Inhomogeneous Excitable Neurons
Institute of Scientific and Technical Information of China (English)
ZHENG Zhi-Gang; WANG Fu-Zhong
2002-01-01
We study the firing synchronization behavior of the inhomogeneous excitable media. Phase synchronizationof neuron firings is observed with increasing the coupling, while the phases of neurons are different (out-of-phase synchronization). We found the synchronization of bursts can be greatly enhanced by applying an external forcing (in-phasesynchronization). The external forcing can be either a periodic or just homogeneous thermal noise. The mechanismresponsible for this enhancement is discussed.PACS numbers: 05.45.-a, 87.10.+e
K*-couplings for the antidecuplet excitation
Azimov, Ya I; Polyakov, M V; Strakovsky, I I; Azimov, Ya.
2007-01-01
We estimate the coupling of K* vector meson to the N-->Theta+ transition employing the unitary simmetry, vector meson dominance, and results of the GRAAL Collaboration on the eta photoproduction off the neutron. Our small numerical value confirms that the CLAS Collaboration null results do not contradict to theoretical expectations for the Theta-production. We also estimate the K*-coupling for the N-->Sigma* excitation, with Sigma* being the Sigma-like antidecuplet partner of the Theta+ baryon.
Dynamics of excitable nodes on random graphs
Indian Academy of Sciences (India)
K Manchanda; T Umeshkanta Singh; R Ramaswamy
2011-11-01
We study the interplay of topology and dynamics of excitable nodes on random networks. Comparison is made between systems grown by purely random (Erd˝os–Rényi) rules and those grown by the Achlioptas process. For a given size, the growth mechanism affects both the thresholds for the emergence of different structural features as well as the level of dynamical activity supported on the network.
Fishbone Instability Excited by Barely Trapped Electrons
Institute of Scientific and Technical Information of China (English)
WANG Zhong-Tian; LONG Yong-Xing; DONG Jia-Qi; WANG Long; Fulvio Zonca
2006-01-01
Fishbone instability excited by barely trapped suprathermal electrons (BTSEs) in tokamaks is investigated theoretically. The frequency of the mode is found to close to procession frequency of BTSEs. The growth rate of the mode is much smaller than that of the ideal magnetohytrodynamic (MHD) internal kink mode that is in contrast to the case of trapped ion driven fishbone instability. The analyses also show that spatial density gradient reversal is necessary for the instability. The correlation of the results with experiments is discussed.
Nuclear fusion in excited hydrogen molecules
Energy Technology Data Exchange (ETDEWEB)
Bellini, M.; Casetti, L.; Rosa-Clot, M. (Florence Univ. (Italy). Dipt. di Fisica Istituto Nazionale di Fisica Nucleare, Florence (Italy))
1990-10-01
We evaluate the nuclear fusion rates in the excited vibrational states of molecules of hydrogen isotopes. The ground state fusion rate is increased by about eight order of magnitude but even in the most favorable situation it is out of any possible experimental test. We discuss the effects due to the nuclear potential in different hyperfine states, and the improvements attainable using coherent states and a solid phase. (orig.).
Love waves excited by a moving source
Zaslavskii, Yu. M.
2016-01-01
The study analyzes the characteristics of surface Love waves excited by the moment of an oscillating torsional force with a point of action that moves uniformly and rectilinearly along the free flat boundary of a medium having the structure of a "layer on a half-space." The azimuthal-angular distribution of the amplitude and Doppler shift in frequency of the wave modes is studied as a function of the motion velocity of a vibrating source and the parameters of the medium.
Controlling nonlinear waves in excitable media
Energy Technology Data Exchange (ETDEWEB)
Puebla, Hector [Departamento de Energia, Universidad Autonoma Metropolitana, Av. San Pablo No. 180, Reynosa-Tamaulipas, Azcapotzalco 02200, DF, Mexico (Mexico)], E-mail: hpuebla@correo.azc.uam.mx; Martin, Roland [Laboratoire de Modelisation et d' Imagerie en Geosciences, CNRS UMR and INRIA Futurs Magique-3D, Universite de Pau (France); Alvarez-Ramirez, Jose [Division de Ciencias Basicas e Ingenieria, Universidad Autonoma Metropolitana-Iztapalapa (Mexico); Aguilar-Lopez, Ricardo [Departamento de Biotecnologia y Bioingenieria, CINVESTAV-IPN (Mexico)
2009-01-30
A new feedback control method is proposed to control the spatio-temporal dynamics in excitable media. Applying suitable external forcing to the system's slow variable, successful suppression and control of propagating pulses as well as spiral waves can be obtained. The proposed controller is composed by an observer to infer uncertain terms such as diffusive transport and kinetic rates, and an inverse-dynamics feedback function. Numerical simulations shown the effectiveness of the proposed feedback control approach.
Computer simulation of electronic excitations in beryllium
Popov, A V
2016-01-01
An effective method for the quantitative description of the electronic excited states of polyatomic systems is developed by using computer technology. The proposed method allows calculating various properties of matter at the atomic level within the uniform scheme. A special attention is paid to the description of beryllium atoms interactions with the external fields, comparable by power to the fields in atoms, molecules and clusters.
Statistical property of the Chandler wobble excitation function
Institute of Scientific and Technical Information of China (English)
LIAO Dechun; LIAO Xinhao; ZHOU Yonghong
2004-01-01
The Chandler wobble excitation function (hereinafter, geodetic excitation) is obtained by removing the seasonal components and low frequency components with periods from several years to decades from the polar motion excitation function derived from SPACE2002 series. The geophysical excitation functions of the individual AAM, OAM, HAM, and two combined excitations of the AAM + OAM and AAM + OAM + HAM at 1d, 5d, 1m and 3m intervals are statistically tested for the hypothesis of the normality, and then tested for the hypotheses of identical distribution between the geodetic and the geophysical excitations. The results show that, among the total 16 components of the two combined excitation functions at 1d, 5d, 1m and 3m intervals,most follow random normal processes, the hypotheses of identical distribution between the geodetic excitation and the two combined excitation are acceptable, while most of the hypotheses of identical distribution between the geodetic excitation and the individual excitations of the AAM, OAM, and HAM are rejectable.These results elucidate from a new point of view, that the excitations from AAM, OAM, and HAM are the main sources of the Chandler wobble, and the Chandler wobble excitation function is of a random normal property.
Studies of pear-shaped nuclei using accelerated radioactive beams
Gaffney, L P; Scheck, M; Hayes, A B; Wenander, F; Albers, M; Bastin, B; Bauer, C; Blazhev, A; Bonig, S; Bree, N; Cederkall, J; Chupp, T; Cline, D; Cocolios, T E; Davinson, T; DeWitte, H; Diriken, J; Grahn, T; Herzan, A; Huyse, M; Jenkins, D G; Joss, D T; Kesteloot, N; Konki, J; Kowalczyk, M; Kroll, Th; Kwan, E; Lutter, R; Moschner, K; Napiorkowski, P; Pakarinen, J; Pfeiffer, M; Radeck, D; Reiter, P; Reynders, K; Rigby, S V; Robledo, L M; Rudigier, M; Sambi, S; Seidlitz, M; Siebeck, B; Stora, T; Thoele, P; Van Duppen, P; Vermeulen, M J; von Schmid, M; Voulot, D; Warr, N; Wimmer, K; Wrzosek-Lipska, K; Wu, C Y; Zielinska, M
2013-01-01
There is strong circumstantial evidence that certain heavy, unstable atomic nuclei are ‘octupole deformed’, that is, distorted into a pear shape. This contrasts with the more prevalent rugby-ball shape of nuclei with reflection-symmetric, quadrupole deformations. The elusive octupole deformed nuclei are of importance for nuclear structure theory, and also in searches for physics beyond the standard model; any measurable electric-dipole moment (a signature of the latter) is expected to be amplified in such nuclei. Here we determine electric octupole transition strengths (a direct measure of octupole correlations) for short-lived isotopes of radon and radium. Coulomb excitation experiments were performed using accelerated beams of heavy, radioactive ions. Our data on and $^{224}$Ra show clear evidence for stronger octupole deformation in the latter. The results enable discrimination between differing theoretical approaches to octupole correlations, and help to constrain suitable candidates for experimental...
Thermal Excitation System for Shearography (TESS)
Lansing, Matthew D.; Bullock, Michael W.
1996-01-01
One of the most convenient and effective methods of stressing a part or structure for shearographic evaluation is thermal excitation. This technique involves heating the part, often convectively with a heat gun, and then monitoring with a shearography device the deformation during cooling. For a composite specimen, unbonds, delaminations, inclusions, or matrix cracking will deform during cooling differently than other more structurally sound regions and thus will appear as anomalies in the deformation field. However, one of the difficulties that cause this inspection to be dependent on the operator experience is the conventional heating process. Fanning the part with a heat gun by hand introduces a wide range of variability from person to person and from one inspection to the next. The goal of this research effort was to conduct research in the methods of thermal excitation for shearography inspection. A computerized heating system was developed for inspection of 0.61 m (24 in.) square panels. The Thermal Excitation System for Shearography (TESS) provides radiant heating with continuous digital measurement of the surface temperature profile to ensure repeatability. The TESS device functions as an accessory to any electronic shearography device.
Electromagnetic Instabilities Excited by Electron Temperature Anisotropy
Institute of Scientific and Technical Information of China (English)
陆全明; 王连启; 周艳; 王水
2004-01-01
One-dimensional particle-in-cell simulations are performed to investigate the nonlinear evolution of electromagnetic instabilities excited by the electron temperature anisotropy in homogeneous plasmas with different parameters. The results show that the electron temperature anisotropy can excite the two right-hand electromagnetic instabilities, one has the frequency higher than Ωe, the other is the whistler instability with larger amplitude,and its frequency is below Ωe. Their dispersion relations are consistent with the prediction from the cold plasma theory. In the initial growth stage (prediction from linear theory), the frequency of the dominant mode (the mode whose amplitude is large enough) of the whistler wave almost does not change, but in the saturation stage the situation is different. In the case that the ratio of electron plasma frequency to cyclotron frequency is larger than 1, the frequency of the dominant mode of the whistler wave drifts from high to low continuously. However, for the case of the ratio smaller than 1, besides the original dominant mode of the whistler wave whose frequency is about 2.6ωe, another dominant mode whose frequency is about 1.55ωe also begins to be excited at definite time,and its amplitude increases with time until it exceeds the original dominant mode.
Spin-polarized spin excitation spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Loth, Sebastian; Lutz, Christopher P; Heinrich, Andreas J, E-mail: lothseb@us.ibm.com, E-mail: heinrich@almaden.ibm.com [IBM Research Division, Almaden Research Center, San Jose, CA 95120 (United States)
2010-12-15
We report on the spin dependence of elastic and inelastic electron tunneling through transition metal atoms. Mn, Fe and Cu atoms were deposited onto a monolayer of Cu{sub 2}N on Cu(100) and individually addressed with the probe tip of a scanning tunneling microscope. Electrons tunneling between the tip and the substrate exchange energy and spin angular momentum with the surface-bound magnetic atoms. The conservation of energy during the tunneling process results in a distinct onset threshold voltage above which the tunneling electrons create spin excitations in the Mn and Fe atoms. Here we show that the additional conservation of spin angular momentum leads to different cross-sections for spin excitations depending on the relative alignment of the surface spin and the spin of the tunneling electron. For this purpose, we developed a technique for measuring the same local spin with a spin-polarized and a non-spin-polarized tip by exchanging the last apex atom of the probe tip between different transition metal atoms. We derive a quantitative model describing the observed excitation cross-sections on the basis of an exchange scattering process.
Study of Linear and Nonlinear Wave Excitation
Chu, Feng; Berumen, Jorge; Hood, Ryan; Mattingly, Sean; Skiff, Frederick
2013-10-01
We report an experimental study of externally excited low-frequency waves in a cylindrical, magnetized, singly-ionized Argon inductively-coupled gas discharge plasma that is weakly collisional. Wave excitation in the drift wave frequency range is accomplished by low-percentage amplitude modulation of the RF plasma source. Laser-induced fluorescence is adopted to study ion-density fluctuations in phase space. The laser is chopped to separate LIF from collisional fluorescence. A single negatively-biased Langmuir probe is used to detect ion-density fluctuations in the plasma. A ring array of Langmuir probes is also used to analyze the spatial and spectral structure of the excited waves. We apply coherent detection with respect to the wave frequency to obtain the ion distribution function associated with externally generated waves. Higher-order spectra are computed to evaluate the nonlinear coupling between fluctuations at various frequencies produced by the externally generated waves. Parametric decay of the waves is observed. This work is supported by U.S. DOE Grant No. DE-FG02-99ER54543.
Electron-impact excitation of Ne4+
Griffin, D. C.; Badnell, N. R.
2000-10-01
We present the results of extensive close-coupling calculations of electron-impact excitation of the C-like ion, Ne4+. We first compare effective collision strengths determined from a 20-level Breit-Pauli R-matrix calculation with those obtained from a 20-level intermediate-coupling frame transformation (ICFT) R-matrix calculation. The ICFT method was also employed to perform two much larger calculations; we compare the effective collision strengths determined from these calculations with each other and with those obtained from the 20-level calculations in order to assess the effects of increasing both the size of the configuration-interaction expansion of the target and the size of the close-coupling expansion. Our final calculation, with 130 terms and 261 levels in the configuration-interaction expansion of the target and 66 terms and 138 levels in the close-coupling expansion, provides improved data for excitation between the levels of the 2s22p2, 2s2p3 and 2p4 configurations and the first close-coupling results for excitation to the levels of the 2s22p3ℓ configurations in Ne4+.
Spin-flavor composition of excited baryons
Fernando, Ishara; Goity, Jose
2015-10-01
The excited baryon masses are analyzed in the framework of the 1 /Nc expansion using the available physical masses and also the masses obtained in lattice QCD for different quark masses. The baryon states are organized into irreducible representations of SU (6) × O (3) , where the [ 56 ,lP =0+ ] ground state and excited baryons, and the [ 56 ,2+ ] and [ 70 ,1- ] excited states are analyzed. The analyses are carried out to O 1 /Nc and first order in the quark masses. The issue of state identifications is discussed. Numerous parameter independent mass relations result at those orders, among them the well known Gell-Mann-Okubo and Equal Spacing relations, as well as additional relations involving baryons with different spins. It is observed that such relations are satisfied at the expected level of precision. Predictions for physically unknown states for each multiplet are obtained. From the quark-mass dependence of the coefficients in the baryon mass formulas an increasingly simpler picture of the spin-flavor composition of the baryons is observed with increasing pion mass (equivalently, increasing mu , d masses), as measured by the number of significant mass operators. This work was supported in part by DOE Contract No. DE-AC05-06OR23177 under which JSA operates the Thomas Jefferson National Accelerator Facility (J. L. G.), and by the NSF (USA) through Grant PHY-0855789 and PHY-1307413 (I. P. F and J. L. G).
Excitation energy transfer in the photosystem I
Energy Technology Data Exchange (ETDEWEB)
Webber, Andrew N
2012-09-25
Photosystem I is a multimeric pigment protein complex in plants, green alage and cyanobacteria that functions in series with Photosystem II to use light energy to oxidize water and reduce carbon dioxide. The Photosystem I core complex contains 96 chlorophyll a molecules and 22 carotenoids that are involved in light harvesting and electron transfer. In eucaryotes, PSI also has a peripheral light harvesting complex I (LHCI). The role of specific chlorophylls in excitation and electron transfer are still unresolved. In particular, the role of so-called bridging chlorophylls, located between the bulk antenna and the core electron transfer chain, in the transfer of excitation energy to the reaction center are unknown. During the past funding period, site directed mutagenesis has been used to create mutants that effect the physical properties of these key chlorophylls, and to explore how this alters the function of the photosystem. Studying these mutants using ultrafast absorption spectroscopy has led to a better understanding of the process by which excitation energy is transferred from the antenna chlorophylls to the electron transfer chain chlorophylls, and what the role of connecting chlorophylls and A_0 chlorophylls is in this process. We have also used these mutants to investigate whch of the central group of six chlorophylls are involved in the primary steps of charge separation and electron transfer.
Excitable Pattern Formation in Inhomogeneous Systems
Prabhakara, Kaumudi; Gholami, Azam; Zykov, Vladimir; Bodenschatz, Eberhard
2015-03-01
On starvation, the amoebae Dictyostelium discoideum signal via the chemo-attractant cyclic adenosine monophosphate (cAMP). The amoebae sense cAMP through membrane receptors and produce their own cAMP. Simultaneously they produce a basal level of Phosphodiesterase, an enzyme that degrades cAMP. Soon a pattern of rotating spiral waves or circular waves is formed at the multi-cellular level. The causal reasons for the selection of one or the other pattern are still unclear. Here we report experimental and theoretical investigations of the pattern-formation of mixtures of cells starved for different times. The excitability of the amoebae depends on the starvation time due to time dependent gene expressions. Cells starved for longer times are known to exhibit increased excitability. We report phase maps of the patterns for mixtures of different combinations of excitability. Numerical simulations of a modified Kessler-Levine model allow us to explain the experimental results and provide new insights into the dynamical behavior of the system. This work is supported by the Max Planck Society.
Non-radiative excitation fluorescence microscopy
Riachy, Lina; Vézy, Cyrille; Jaffiol, Rodolphe
2016-03-01
Non-radiative Excitation Fluorescence Microscopy (NEFM) constitutes a new way to observe biological samples beyond the diffraction limit. Non-radiative excitation of the samples is achieved by coating the substrate with donor species, such as quantum dots (QDs). Thus the dyes are not excited directly by the laser source, as in common fluorescence microscopy, but through a non-radiative energy transfer. To prevent dewetting of the donor film, we have recently implemented a silanization process to covalently bond the QDs on the substrate. An homogeneous monolayer of QDs was then deposited on only one side of the coverslips. Atomic force microscopy was then used to characterize the QD layer. We highlight the potential of our method through the study of Giant Unilamellar Vesicles (GUVs) labeled with DiD as acceptor, in interaction with surface functionalized with poly-L-lysine. In the presence of GUVs, we observed a quenching of QDs emission, together with an emission of DiD located in the membrane, which clearly indicated that non-radiative energy transfer from QDs to DiD occurs.
The excitation of tsunamis by deep earthquakes
Okal, Emile A.
2017-04-01
Motivated by the detection of a millimetric tsunami following the deep earthquake of 2013 May 24 in the Sea of Okhotsk (depth 603 km; record moment M0 = 3.95 × 1028 dyn cm), we present a number of theoretical studies of the influence of source depth, zs, on the excitation of tsunamis by dislocation sources. In the framework of the static deformation of an elastic half-space, we show that the energy available for tsunami excitation by a seismic source whose depth is significantly greater than source dimensions is expected to vary as M_0^2/z_{{s}}^2, in contrast to the classical scaling as M_0^{4/3} for shallow sources. This is verified by numerical simulations based on the MOST algorithm, which also confirm the interpretation of the millimetric signals observed on DART sensors during the 2013 event. The normal-mode formalism, which considers tsunamis as a special branch of the spheroidal oscillations of the Earth in the presence of a water layer at its surface, also predicts an M_0^2/z_{{s}}^2 scaling for point source double-couples, and confirms millimetric amplitudes in the geometry of the DART buoys having recorded the 2013 Okhotsk tsunami. A general investigation of potential tsunami excitation as a function of depth for realistic intermediate and deep sources suggests the admittedly remote possibility of damaging events if deep earthquakes even greater than the 2013 event could occur at the bottom of Wadati-Benioff zones.
Cyanogen excitation in diffuse interstellar clouds
Roth, Katherine C.; Meyer, David M.
1995-03-01
We present high signal-to-noise ratio observations of optical CN absorption from the B (2)sigma(+) -X (2)sigma(+) (0, 0) and (1, 0) vibrational bands in the five diffuse lines of sight toward zeta Ophiuchi, zeta Persei, HD 27778, HD 21483, and HD 154368. The observed level of CN excitation is consistent with direct satellite and rocket measurements of the cosmic microwave background radiation (CMBR), implying that local collision effects are small. The weak 2.64 mm CN line emission observed toward HD 21483 and HD 154368 is used to correct the observed CN excitation temperatures and derive a weighted mean CMBR temperature at 2.64 mm of 2.729(+0.023, -0.031) K which agrees remarkably well with the Cosmic Background Explorer Satellite (COBE) measurement obtained with the Far Infrared Absolute Spectrometer (FIRAS) instrument of 2.726 +/- 0.010 K. These absorption data were obtained during 10 separate observing runs, and we find excellent agreement between independent equivalent width measurements resulting from widely varying instrument combinations. Finally we discuss the limitations and future applications of CN excitation absorption-line measurements.
Siu-Siu, Guo; Qingxuan, Shi
2017-03-01
In this paper, single-degree-of-freedom (SDOF) systems combined to Gaussian white noise and Gaussian/non-Gaussian colored noise excitations are investigated. By expressing colored noise excitation as a second-order filtered white noise process and introducing colored noise as an additional state variable, the equation of motion for SDOF system under colored noise is then transferred artificially to multi-degree-of-freedom (MDOF) system under white noise excitations with four-coupled first-order differential equations. As a consequence, corresponding Fokker-Planck-Kolmogorov (FPK) equation governing the joint probabilistic density function (PDF) of state variables increases to 4-dimension (4-D). Solution procedure and computer programme become much more sophisticated. The exponential-polynomial closure (EPC) method, widely applied for cases of SDOF systems under white noise excitations, is developed and improved for cases of systems under colored noise excitations and for solving the complex 4-D FPK equation. On the other hand, Monte Carlo simulation (MCS) method is performed to test the approximate EPC solutions. Two examples associated with Gaussian and non-Gaussian colored noise excitations are considered. Corresponding band-limited power spectral densities (PSDs) for colored noise excitations are separately given. Numerical studies show that the developed EPC method provides relatively accurate estimates of the stationary probabilistic solutions, especially the ones in the tail regions of the PDFs. Moreover, statistical parameter of mean-up crossing rate (MCR) is taken into account, which is important for reliability and failure analysis. Hopefully, our present work could provide insights into the investigation of structures under random loadings.
Impact self-excited vibrations of linear motor
Zhuravlev, V. Ph.
2010-08-01
Impact self-exciting vibration modes in a linear motor of a monorail car are studied. Existence and stability conditions of self-exciting vibrations are found. Ways of avoiding the vibrations are discussed.
Using LabVIEW: Simulation Exciter of Devices Jamming
Elan Djaelani; Nina Siti Aminah; Ridodi Anantaprama
2012-01-01
It has been made exciter of devices jamming, by using component voltage controled oscilator (vco). It has been done measurements: signal noise,signal sawtooth and level DC voltage at those signals. Being wanted those devices jamming could be raised it’s performance. With helping software LabVIEW being made exciter. Result Simulation are graphic and table relation between input exciter and it’s output. Input exciter are: signal sawtooth, signal noise and level DC voltage that could be changing...
Few Issues Related to an Electrodynamic Exciter Control
Čala, M.
2015-01-01
There are multiple problems to solve when controlling an electromagnetic exciter for vibrations generation. Main challenge is to straighten a frequency response of an exciter which is normally not uniform due to resonances resulting from the mechanical construction of an exciter, specimen to test, or mounting fixture. This paper describes number of aspects to consider, which arose during implementation of the control system for small electrodynamic exciter on the Department of Control and Ins...
Quantum Yield Characterization and Excitation Scheme Optimization of Upconverting Nanoparticles
DEFF Research Database (Denmark)
Liu, Haichun; Xu, Can T.; Jensen, Ole Bjarlin
2014-01-01
Upconverting nanoparticles suffer from low quantum yield in diffuse optical imaging, especially at low excitation intensities. Here, the power density dependent quantum yield is characterized, and the excitation scheme is optimized based on such characterization......Upconverting nanoparticles suffer from low quantum yield in diffuse optical imaging, especially at low excitation intensities. Here, the power density dependent quantum yield is characterized, and the excitation scheme is optimized based on such characterization...
Quantum Yield Characterization and Excitation Scheme Optimization of Upconverting Nanoparticles
DEFF Research Database (Denmark)
Liu, Haichun; Xu, Can T.; Jensen, Ole Bjarlin;
2014-01-01
Upconverting nanoparticles suffer from low quantum yield in diffuse optical imaging, especially at low excitation intensities. Here, the power density dependent quantum yield is characterized, and the excitation scheme is optimized based on such characterization......Upconverting nanoparticles suffer from low quantum yield in diffuse optical imaging, especially at low excitation intensities. Here, the power density dependent quantum yield is characterized, and the excitation scheme is optimized based on such characterization...
Anomalous drift of spiral waves in heterogeneous excitable media
Sridhar, S; Panfilov, Alexander V
2009-01-01
We study the drift of spiral waves in a simple model of heterogeneous excitable medium, having gradients in local excitability or cellular coupling. For the first time, we report the anomalous drift of spiral waves towards regions having higher excitability, in contrast to all earlier observations in reaction-diffusion models of excitable media. Such anomalous drift can promote the onset of complex spatio-temporal patterns, e.g., those responsible for life-threatening arrhythmias in the heart.
Self-excitation of a diagonal MHD channel
Energy Technology Data Exchange (ETDEWEB)
Doperchuk, I.I.; Koneyev, S.M.A.
1982-01-01
Questions are examined of self-excitation of a diagonal MHD channel. Conditions are obtained for self-excitation using 0-dimensional approximation. An algorithm is presented for calculating the optimal self-exciting diagonal channel with regard for development and separation of the boundary layers, presence of near-electrode drops in voltage. Graphs are presented for the transitional regimes of channel operation with intermediate point of connection of the excitation winding.
Simultaneous two-photon excitation of photodynamic therapy agents
Energy Technology Data Exchange (ETDEWEB)
Wachter, E.A.; Fisher, W.G. [Oak Ridge National Lab., TN (United States)]|[Photogen, Inc., Knoxville, TN (United States); Partridge, W.P. [Oak Ridge National Lab., TN (United States); Dees, H.C. [Photogen, Inc., Knoxville, TN (United States); Petersen, M.G. [Univ. of Tennessee, Knoxville, TN (United States). College of Veterinary Medicine
1998-01-01
The spectroscopic and photochemical properties of several photosensitive compounds are compared using conventional single-photon excitation (SPE) and simultaneous two-photon excitation (TPE). TPE is achieved using a mode-locked titanium:sapphire laser, the near infrared output of which allows direct promotion of non-resonant TPE. Excitation spectra and excited state properties of both type 1 and type 2 photodynamic therapy (PDT) agents are examined.
Excitation Spectrum of Three Dressed Bose-Einstein Condensates
Institute of Scientific and Technical Information of China (English)
OU-YANG Zhong-Wen; KUANG Le-Man
2000-01-01
We study quantum dynamics of three dressed Bose-Einstein condensates in a high-Q cavity. The quasiparticle excitation spectrum of this system is found numerically. The stability of the quasiparticle excitation is analyzed. It is shown that there exist instabilities in the excitation spectrum.
Radial Excitations in the Global Colour Soliton Model
Institute of Scientific and Technical Information of China (English)
WANG Bin; LIU Yu-Xin
2007-01-01
@@ With the Munczek-Nemirovsky model of the effective gluon propagator in the global colour model, we study the radially excited solitons in which one quark is excited and the other two are at the ground state. The obtained masses of the two radial excitations are comparable with the experimental data.
Wei, Sha; Han, Qinkai; Peng, Zhike; Chu, Fulei
2016-05-01
Some system parameters in mechanical systems are always uncertain due to uncertainties in geometric and material properties, lubrication condition and wear. For a more reasonable estimation of dynamic analysis of the parametrically excited system, the effect of uncertain parameters should be taken into account. This paper presents a new non-probabilistic analysis method for solving the dynamic responses of parametrically excited systems under uncertainties and multi-frequency excitations. By using the multi-dimensional harmonic balance method (MHBM) and the Chebyshev inclusion function (CIF), an interval multi-dimensional harmonic balance method (IMHBM) is obtained. To illustrate the accuracy of the proposed method, a time-varying geared system of wind turbine with different kinds of uncertainties is demonstrated. By comparing with the results of the scanning method, it is shown that the presented method is valid and effective for the parametrically excited system with uncertainties and multi-frequency excitations. The effects of some uncertain system parameters including uncertain mesh stiffnesses and uncertain bearing stiffnesses on the frequency responses of the system are also discussed in detail. It is shown that the dynamic responses of the system are insensitive to the uncertain mesh stiffness and bearing stiffnesses of the planetary gear stage. The uncertain bearing stiffnesses of the intermediate and high-speed stages will lead to relatively large uncertainties in the dynamic responses around resonant regions. It will provide valuable guidance for the optimal design and condition monitoring of wind turbine gearboxes.
Energy Technology Data Exchange (ETDEWEB)
Guevara, Z. E., E-mail: zjguevaram@unal.edu.co; Torres, D. A., E-mail: datorresg@unal.edu.co [Physics Department, Universidad Nacional de Colombia, Bogotá D.C. (Colombia)
2016-07-07
In this contribution the challenges in the use of a setup to simultaneously measure lifetimes and g-factor values will be presented. The simultaneous use of the transient field technique and the Doppler Shift Attenuation Method, to measure magnetic moments and lifetimes respectively, allows to obtain a complete characterization of the currents of nucleons and the deformation in excited states close to the ground state. The technique is at the moment limited to Coulomb excitation and alpha-transfer reactions, what opens an interesting perspective to consider this type of experiments with radioactive beams. The use of deep-inelastic and fusion-evaporation reactions will be discussed. An example of a setup that makes use of a beam of {sup 106}Cd to study excited states of {sup 110}Sn and the beam nuclei itself will be presented.
Culturing conditions determine neuronal and glial excitability.
Stoppelkamp, Sandra; Riedel, Gernot; Platt, Bettina
2010-12-15
The cultivation of pure neuronal cultures is considered advantageous for the investigation of cell-type specific responses (such as transmitter release and also pharmacological agents), however, divergent results are a likely consequence of media modifications and culture composition. Using Fura-2 based imaging techniques, we here set out to compare calcium responses of rat hippocampal neurones and glia to excitatory stimulation with l-glutamate in different culture types and media. Neurones in neurone-enriched cultures had increased responses to 10 μM and 100 μM l-glutamate (+43 and 45%, respectively; p's< 0.001) and a slower recovery compared to mixed cultures, indicating heightened excitability. In matured (15-20 days in vitro) mixed cultures, neuronal responder rates were suppressed in a neurone-supportive medium (Neurobasal-A, NB: 65%) compared to a general-purpose medium (supplemented minimal essential medium, MEM: 96%). Glial response size in contrast did not differ greatly in isolated or mixed cultures maintained in MEM, but responder rates were suppressed in both culture types in NB (e.g. 10 μM l-glutamate responders in mixed cultures: 29% in NB, 71% in MEM). This indicates that medium composition is more important for glial excitability than the presence of neurones, whereas the presence of glia has an important impact on neuronal excitability. Therefore, careful consideration of culturing conditions is crucial for interpretation and comparison of experimental results. Especially for investigations of toxicity and neuroprotection mixed cultures may be more physiologically relevant over isolated cultures as they comprise aspects of mutual influences between glia and neurones.
The 2+ excitation of the Hoyle state
Directory of Open Access Journals (Sweden)
Khoa Dao T.
2016-01-01
Full Text Available To understand why the 2+ excitation of the Hoyle state was so difficult to observe in the direct reaction experiments with the 12C target, a detailed folding model + coupled-channel analysis of the inelastic α+12C scattering at Elab = 240 and 386 MeV has been done using the complex optical potential and inelastic scattering form factor obtained from the double-folding model using the nuclear transition densities predicted by the antisymmetrized molecular dynamics. With the complex strength of the density dependent nucleon-nucleon interaction fixed by the optical model description of the elastic α+12C scattering, the inelastic scattering form factor was fine tuned to the best coupled-channel description of the (α, α′ cross section measured for each excited state of 12C, and the corresponding isoscalar Eλ transition strength has been accurately determined. The present analysis of the (α, α′ data measured in the energy bins around Ex ≈ 10 MeV has unambiguously revealed the E2 transition strength that should be assigned to the 22+ state of 12C. A very weak transition strength B(E2; 01+ → 22+ ≈ 3 e2fm4 has been established, which is smaller than the E2 strength predicted for the transition from the Hoyle state to the 22+ state by at least two orders of magnitude. This is one of the main reasons why the direct excitation of the 22+ state of 12C has been difficult to observe in the experiments.
Superparamagnetic segmentation by excitable neural systems.
Neirotti, Juan P; Kurcbart, Samuel M; Caticha, Nestor
2003-09-01
Magnetic modeling for clustering or segmentation purposes can either associate the image data to external quenched fields or to the interactions among a set of auxiliary variables. The latter gives rise to superparamagnetic segmentation and is usually done with Potts systems. We have used the superparamagnetic clustering technique to segment images, with the aid of different associated systems. Results using Potts model are comparable to those obtained using excitable FitzHugh-Nagumo and Morris-Lecar model neurons. Interactions between the associated system components are a function of the difference of luminosity on a gray scale of neighbor pixels and the difference of membrane potential.
Nonlinear Excitation in a Ferrimagnetic Zigzag Chain
Institute of Scientific and Technical Information of China (English)
王为忠
2003-01-01
We study the nonlinear excitation(solitons)in a ferrimagnetic polymer chain by using a total Hamiltonian consisting of Su-Schrieffer-Heeger Hamiltonian and a Hubbard term.At half-filling,the distortion of lattices forms domain wall solitons,while the spin configuration forms envelope solitons.The soliton pair is obtained in a range of the electron-electron(e-e)interaction U,which depends on the electron-phonon(e-ph)interaction.The spin solitons corresponding to the left domain wall and the right domain wall of the displacement are quite different.
Excited states of muonium in atomic hydrogen
Indian Academy of Sciences (India)
V S Kulhar
2006-06-01
Muonium formation in excited states in muon-hydrogen charge-exchange collision is investigated using a method developed in a previous paper. Differential cross-section results are found to resemble positronium formation cross-section results of positron-hydrogen charge-exchange problem. Forward differential and integrated cross-sections are computed for muon energy of 2 keV and higher. Total muonium formation cross-sections are computed using Jackson and Schiff scaling rules. Muonium formation cross-section results obtained from proton-hydrogen charge-exchange cross-section results, using velocity scaling are compared with the results of the present calculation.
Single-particle excitations in 89Y
Wise, J. E.; Hersman, F. W.; Heisenberg, J. H.; Milliman, T. E.; Connelly, J. P.; Calarco, J. R.; Papanicolas, C. N.
1990-09-01
Inelastic-electron-scattering cross sections have been measured for the first three excitations in 89Y at forward angles for momentum transfers of 1.25
Radial excitations of current-carrying vortices
Hartmann, Betti; Michel, Florent; Peter, Patrick
2017-04-01
We report on the existence of a new type of cosmic string solutions in the Witten model with U (1) × U (1) symmetry. These solutions are superconducting with radially excited condensates that exist for both gauged and ungauged currents. Our results suggest that these new configurations can be macroscopically stable, but microscopically unstable to radial perturbations. Nevertheless, they might have important consequences for the network evolution and particle emission. We discuss these effects and their possible signatures. We also comment on analogies with non-relativistic condensed matter systems where these solutions may be observable.
Paramagnetic excited vortex states in superconductors
Gomes, Rodolpho Ribeiro; Doria, Mauro M.; Romaguera, Antonio R. de C.
2016-06-01
We consider excited vortex states, which are vortex states left inside a superconductor once the external applied magnetic field is switched off and whose energy is lower than of the normal state. We show that this state is paramagnetic and develop here a general method to obtain its Gibbs free energy through conformal mapping. The solution for any number of vortices in any cross-section geometry can be read off from the Schwarz-Christoffel mapping. The method is based on the first-order equations used by Abrikosov to discover vortices.
On vortices heating biological excitable media
Energy Technology Data Exchange (ETDEWEB)
Bini, D. [Istituto per le Applicazioni del Calcolo ' M. Picone' , CNR, I-00161 Rome (Italy); International Center for Relativistic Astrophysics - I.C.R.A., University of Rome ' La Sapienza' , I-00185 Rome (Italy); Cherubini, C. [Nonlinear Physics and Mathematical Modeling Lab, Engineering Faculty, University Campus Bio-Medico, I-00128 Rome (Italy); International Center for Relativistic Astrophysics - I.C.R.A., University of Rome ' La Sapienza' , I-00185 Rome (Italy)], E-mail: C.Cherubini@unicampus.it; Filippi, S. [Nonlinear Physics and Mathematical Modeling Lab, Engineering Faculty, University Campus Bio-Medico, I-00128 Rome (Italy); International Center for Relativistic Astrophysics - I.C.R.A., University of Rome ' La Sapienza' , I-00185 Rome (Italy)
2009-11-30
An extension of the Hodgkin-Huxley mathematical model for the propagation of nerve signal which takes into account dynamical heat transfer in biological tissue is derived and fine tuned with existing experimental data. The medium is heated by Joule's effect associated with action potential propagation, leading to characteristic thermal patterns in association with spiral and scroll waves. The introduction of heat transfer-necessary on physical grounds-provides a novel way to directly observe the movement, regular or chaotic, of the tip of spiral waves in numerical simulations and possibly in experiments regarding different biological excitable media.
Excited triplet state spectroscopy in the infrared
Baiardo, Joseph; Mukherjee, Ranajit; Vala, Martin
1982-03-01
A new method for the investigation of the infrared spectra of metastable excitedelectronic states is presented. With a Fourier Transform infrared spectrometer as the probe and a CW Xe lamp source as the pump, the infrared spectrum of the lowest triplet state of triphenylene isolated in a N 2 matrix at 15K has been examined. CH out-of-plane wagging modes are prominent and shifted from their ground state frequencies. It is expected that when fully developed this method will provide important information on excited state force constants and potential energy surfaces.
Evolution of Spiral Waves in Excitable Systems
Institute of Scientific and Technical Information of China (English)
KEN Ji-Rong; ZHU Tao; MO Shu-Fan
2009-01-01
Spiral waves, whose rotation center can be regarded as a point defect, widely exist in various two-dimensional excitable systems. In this paper, by making use of Duan's topological current theory, we obtain the charge density of spiral waves and the topological inner structure of its topological charge. The evolution of spiral wave is also studied from the topological properties of a two-dimensional vector field. The spiral waves are found generating or annihilating at the limit points and encountering, splitting, or merging at the bifurcation points of the two-dimensional vector field. Some applications of our theory are also discussed.
Ultra-short strong excitation of two-level systems
Jha, Pankaj K.; Eleuch, Hichem; Grazioso, Fabio
2014-11-01
We present a model describing the use of ultra-short strong pulses to control the population of the excited level of a two-level quantum system. In particular, we study an off-resonance excitation with a few cycles pulse which presents a smooth phase jump i.e. a change of the pulse's phase which is not step-like, but happens over a finite time interval. A numerical solution is given for the time-dependent probability amplitude of the excited level. The control of the excited level's population is obtained acting on the shape of the phase transient, and other parameters of the excitation pulse.
The photodissociation and reaction dynamics of vibrationally excited molecules
Energy Technology Data Exchange (ETDEWEB)
Crim, F.F. [Univ. of Wisconsin, Madison (United States)
1993-12-01
This research determines the nature of highly vibrationally excited molecules, their unimolecular reactions, and their photodissociation dynamics. The goal is to characterize vibrationally excited molecules and to exploit that understanding to discover and control their chemical pathways. Most recently the author has used a combination of vibrational overtone excitation and laser induced fluorescence both to characterize vibrationally excited molecules and to study their photodissociation dynamics. The author has also begun laser induced grating spectroscopy experiments designed to obtain the electronic absorption spectra of highly vibrationally excited molecules.
Excitability in optical systems close to Z2-symmetry
Beri, Stefano; Gelens, Lendert; Van der Sande, Guy; Mezosi, Gabor; Sorel, Marc; Danckaert, Jan; Verschaffelt, Guy; 10.1016/j.physleta.2009.11.070
2011-01-01
We report theoretically and experimentally on excitability in semiconductor ring lasers in order to reveal a mechanism of excitability, general for systems close to Z2-symmetry. The global shapes of the invariant manifolds of a saddle in the vicinity of a homoclinic loop determine the origin of excitability and the fea- tures of the excitable pulses. We show how to experimentally make a semiconductor ring laser excitable by breaking the Z2-symmetry in a controlled way. The experiments confirm the theoretical predictions.
Collisional Excitation of Automotive Fuel Components (ethanol and Isooctane)
Cobb, Rachelle H.; White, Allen R.; Devasher, Rebecca B.
2009-06-01
It is possible to excite fuel components indirectly via a 10.6 um CO2 laser. A 9% solution of isopropanol in ethanol was used, as it has a strong absorption cross section at 10.6 um. CO2 laser excitation of pure ethanol caused little or no change in absorption in the C-H stretch region. However, the ethanol/isopropanol mixture did show a response proportional to laser excitation. Further studies indicate that excitation of isooctane/isopropanol mixture is also possible via collisional energy transfer between the laser excited isopropanol and isooctane.
Investigation of Nanoscale Interactions by Means of Subharmonic Excitation.
Chiesa, Matteo; Gadelrab, Karim; Stefancich, Marco; Armstrong, Peter; Li, Guang; Souier, Tewfik; Thomson, Neil H; Barcons, Victor; Font, Josep; Verdaguer, Albert; Phillips, Michael A; Santos, Sergio
2012-08-16
Multifrequency atomic force microscopy holds promise as a method to provide qualitative and quantitative information about samples with high spatial resolution. Here, we provide experimental evidence of the excitation of subharmonics in ambient conditions in the regions where capillary interactions are predicted to be the mechanism of excitation. We also experimentally decouple a second mechanism for subharmonic excitation that is highly independent of environmental conditions such as relative humidity. This implies that material properties could be mapped. Subharmonic excitation could lead to experimental determination of surface water affinity in the nanoscale whenever water interactions are the mechanism of excitation.
Seeded excitation avalanches in off-resonantly driven Rydberg gases
Simonelli, Cristiano; Masella, Guido; Asteria, Luca; Arimondo, Ennio; Ciampini, Donatella; Morsch, Oliver
2016-01-01
We report an experimental investigation of the facilitated excitation dynamics in off-resonantly driven Rydberg gases by separating the initial off-resonant excitation phase from the facilitation phase, in which successive facilitation events lead to excitation avalanches. We achieve this by creating a controlled number of initial seed excitations. Greater insight into the avalanche mechanism is obtained from an analysis of the full counting distributions. We also present simple mathematical models and numerical simulations of the excitation avalanches that agree well with our experimental results.
Modeling short-pulse laser excitation of dielectric materials
DEFF Research Database (Denmark)
Wædegaard, Kristian Juncher; Sandkamm, Ditte Både; Haahr-Lillevang, Lasse
2014-01-01
A theoretical description of ultrashort-pulse laser excitation of dielectric materials based on strong-field excitation in the Keldysh picture combined with a multiple-rateequation model for the electronic excitation including collisional processes is presented. The model includes light attenuation...... in a self-consistent manner and changing optical properties described in a Drude picture. The model can be used to calculate the electronic excitation as a function of time and depth, and from these quantities the time-dependent optical parameters as well as the ablation depth can be derived....... The simulations provide insight into the excitation and propagation dynamics of short-pulse excitation and show that at increasing fluence the excitation becomes localized near the material surface and gives rise to strongmodifications of the optical properties of the material....
Excitation of spin echo by pulses with linear frequency modulation
Baruzdin, S. A.
2015-03-01
The excitation of a spin echo by two pulses with linear frequency modulation, upon which the pulse parameters ensure maximal compression of the response in time, is considered. The frequency of the excitation pulses was changed by a step law, approximating its linear rise. The transfer matrix of the state of the spin system for pulses with linear frequency modulation is found by solving the Bloch equations. The shape of the envelope of the spin echo in thin magnetic cobalt films, as well as the dependence of the echo amplitude on the parameters of the excitation pulses, is determined. The amplitudes of the excitation pulses, which ensure the excitation of the echo maximal amplitude for various values of the frequency deviation, are found. It is shown that the use of pulses with linear frequency modulation makes it possible to obtain the same echo amplitude as with the use of simple excitation pulses for a substantially smaller amplitude and power of excitation pulses.
Fusion excitation functions involving transitional nuclei
Energy Technology Data Exchange (ETDEWEB)
Rehm, K.E.; Jiang, C.L.; Esbensen, H. [and others
1995-08-01
Measurements of fusion excitation functions involving transitional nuclei {sup 78}Kr and {sup 100}Mo showed a different behavior at low energies, if compared to measurements with {sup 86}Kr and {sup 92}Mo. This points to a possible influence of nuclear structure on the fusion process. One way to characterize the structure of vibrational nuclei is via their restoring force parameters C{sub 2} which can be calculated from the energy of the lowest 2{sup +} state and the corresponding B(E2) value. A survey of the even-even nuclei between A = 28-150 shows strong variations in C{sub 2} values spanning two orders of magnitude. The lowest values for C{sub 2} are observed for {sup 78}Kr, {sup 104}Ru and {sup 124}Xe followed by {sup 74,76}Ge, {sup 74,76}Se, {sup 100}Mo and {sup 110}Pd. In order to learn more about the influence of {open_quotes}softness{close_quotes} on the sub-barrier fusion enhancement, we measured cross sections for evaporation residue production for the systems {sup 78}Kr + {sup 104}Ru and {sup 78}Kr + {sup 76}Ge with the gas-filled magnet technique. For both systems, fusion excitation functions involving the closed neutron shell nucleus {sup 86}Kr were measured previously. The data are presently being analyzed.
MEMS Logic Using Mixed-Frequency Excitation
Ilyas, Saad
2017-06-22
We present multi-function microelectromechanical systems (MEMS) logic device that can perform the fundamental logic gate AND, OR, universal logic gates NAND, NOR, and a tristate logic gate using mixed-frequency excitation. The concept is based on exciting combination resonances due to the mixing of two or more input signals. The device vibrates at two steady states: a high state when the combination resonance is activated and a low state when no resonance is activated. These vibration states are assigned to logical value 1 or 0 to realize the logic gates. Using ac signals to drive the resonator and to execute the logic inputs unifies the input and output wave forms of the logic device, thereby opening the possibility for cascading among logic devices. We found that the energy consumption per cycle of the proposed logic resonator is higher than those of existing technologies. Hence, integration of such logic devices to build complex computational system needs to take into consideration lowering the total energy consumption. [2017-0041
One-phonon excitations in hot nuclei
Energy Technology Data Exchange (ETDEWEB)
Vdovin, A.I.; Kosov, D.S. [Joint Institute for Nuclear Research, Moscow (Russian Federation)
1995-05-01
Equations of the random-phase approximation for hot nuclei are derived in the formalism of thermo-field dynamics. The model Hamiltonian used in the derivation involves separable effective interactions in the particle-particle and particl-hole channels. This initial Hamiltonian that forms the basis of the quasiparticle-phonon model at T = O is expressed in terms of thermal quasiparticles by means of two successive canonical transformations, i.e., by the conventional and thermal Bogolyubov transformations. The coefficients in the transformations are determined by minimizing the free-energy potential of a hot nucleus in the thermal vacuum state. The part that describes excitations of the hot nucleus in the random-phase approximation is then singled out in the resulting Hamiltonian at T {ne} O. The variational principle is used to derive equations for one-phonon excitations. If the Hamiltonian involves only residual particle-hole interaction, these equations coincide with those obtained earlier by means of Green`s functions and linearization of the equations of motion. The approach developed here can be used to extend the treatment beyond the random-phase approximation. 15 refs.
Electromagnetic excitation of the Delta(1232) resonance
Energy Technology Data Exchange (ETDEWEB)
V. Pascalutsa; M. Vanderhaeghen; Shin Nan Yang
2006-09-05
We review the description of the lowest-energy nucleon excitation--the Delta(1232)-resonance. Much of the recent effort has been focused on the precision measurements of the nucleon to Delta transition by means of electromagnetic probes. We review the results of those measurements and confront them with the state-of-the-art calculations based on chiral effective-field theories (EFT), lattice QCD, and QCD-inspired models. Some of the theoretical approaches are reviewed in detail. In particular, we describe the chiral EFT of QCD in the energy domain of the Delta-resonance, and its applications to the electromagnetic nucleon-to-Delta transition (gamma N Delta). We also describe the recent dynamical and unitary-isobar models of pion electroproduction which are extensively used in the extraction of the gamma* N Delta form factors from experiment. Furthermore, we discuss the link of the gamma* N Delta form factors to generalized parton distributions (GPDs), as well as the predictions of perturbative QCD for these transition form factors. The present status of understanding the Delta-resonance properties and the nature of its excitation is summarized.
Analysis of orbitally excited B-mesons
Albrecht, Zoltan; Quast, Gunter
2003-01-01
This thesis reports on the study of orbitally excited B** mesons in DELPHI b-events taken in the years 1994 to 2000 with the DELPHI detector at the LEP collider. The analyses presented represent the result of applying much improved and extended techniques of spectroscopy since the first DELPHI publication in 1995. A major improvement has occurred in the area of particle identification, where a neural network approach has been implemented in the DELPHI software package. Developments in the area of neural networks have led to much improved enrichment of the excited B states. The Bˆ{**} neural networks identify, on a track-by-track basis, the decay pion/kaon originating from the Bˆ{**} decay, suppressing background and keeping signal events in an efficient way. To improve detector resolution, a further application of neural networks has been applied to reconstruct the underlying Q-value. The corresponding network gives a correction on existing measurements of the Q-value in the form of a probability density fu...
Vertical Distribution of Vibrationally Excited Hydroxyl
Grygalashvyly, Mykhaylo; Becker, Erich; Sonnemann, Gerd
2016-04-01
Knowledge about the vertical distribution of the vibrationally excited states of hydroxyl (OH*) is important for the interpretation of airglow measurements with respect to dynamical processes in the mesopause region. We derive an approximate analytical expression for the distribution of OH* that highlights the dependence on atomic oxygen and temperature. In addition, we use an advanced numerical model for the formation and relaxation of OH* and investigate the distributions of the different vibrationally exited states of OH*. For the production of OH*, the model includes the reaction of atomic hydrogen with ozone, as well as the reaction of atomic oxygen with hydroperoxy radicals. As loss processes we include 1) deactivation by atomic oxygen, molecular oxygen, and molecular nitrogen, 2) spontaneous emission, and 3) loss due to chemical reaction with atomic oxygen. All these processes take the dependence on the vibrational number into account. The quenching by molecular and atomic oxygen is parameterized by a multi-quantum relaxation scheme. This diagnostic model for OH* has been implemented as part of a chemistry-transport model that is driven by the dynamics simulated with the KMCM (Kühlungsborn Mechanistic general Circulation Model). Numerical results confirm that emission from excited states with higher vibrational number is weaker and emanates from higher altitudes. In addition we find that the OH*-peak altitudes depend significantly on season and latitude. This behavior is mainly controlled by the corresponding variations of atomic oxygen and temperature, as is also confirmed by the aforementioned approximate theory.
Topological excitations in a kagome magnet.
Pereiro, Manuel; Yudin, Dmitry; Chico, Jonathan; Etz, Corina; Eriksson, Olle; Bergman, Anders
2014-09-08
Chirality--that is, left or right handedness--is present in many scientific areas, and particularly in condensed matter physics. Inversion symmetry breaking relates chirality with skyrmions, which are protected field configurations with particle-like and topological properties. Here we show that a kagome magnet, with Heisenberg and Dzyaloshinskii-Moriya interactions, causes non-trivial topological and chiral magnetic properties. We also find that under special circumstances, skyrmions emerge as excitations, having stability even at room temperature. Chiral magnonic edge states of a kagome magnet offer, in addition, a promising way to create, control and manipulate skyrmions. This has potential for applications in spintronics, that is, for information storage or as logic devices. Collisions between these particle-like excitations are found to be elastic at very low temperature in the skyrmion-skyrmion channel, albeit without mass-conservation. Skyrmion-antiskyrmion collisions are found to be more complex, where annihilation and creation of these objects have a distinct non-local nature.
A novel phase portrait for neuronal excitability.
Directory of Open Access Journals (Sweden)
Guillaume Drion
Full Text Available Fifty years ago, FitzHugh introduced a phase portrait that became famous for a twofold reason: it captured in a physiological way the qualitative behavior of Hodgkin-Huxley model and it revealed the power of simple dynamical models to unfold complex firing patterns. To date, in spite of the enormous progresses in qualitative and quantitative neural modeling, this phase portrait has remained a core picture of neuronal excitability. Yet, a major difference between the neurophysiology of 1961 and of 2011 is the recognition of the prominent role of calcium channels in firing mechanisms. We show that including this extra current in Hodgkin-Huxley dynamics leads to a revision of FitzHugh-Nagumo phase portrait that affects in a fundamental way the reduced modeling of neural excitability. The revisited model considerably enlarges the modeling power of the original one. In particular, it captures essential electrophysiological signatures that otherwise require non-physiological alteration or considerable complexification of the classical model. As a basic illustration, the new model is shown to highlight a core dynamical mechanism by which calcium channels control the two distinct firing modes of thalamocortical neurons.
Tunneling ionization of vibrationally excited nitrogen molecules
Kornev, Aleksei S.; Zon, Boris A.
2015-09-01
Ionization of molecular nitrogen plays an important role in the process of light-filament formation in air. In the present paper we theoretically investigated tunneling ionization of the valence 3 σg and 1 πu shells in a N2 molecule using a strong near-infrared laser field. This research is based on our previously proposed theory of anti-Stokes-enhanced tunneling ionization with quantum accounting for the vibrationally excited states of the molecules [A. S. Kornev and B. A. Zon, Phys. Rev. A 86, 043401 (2012), 10.1103/PhysRevA.86.043401]. We demonstrated that if the N2 molecule is ionized from the ground vibrational state, then the contribution of the 1 πu orbital is 0.5%. In contrast, for vibrationally excited states with a certain angle between the light polarization vector and the molecule axis, both shells can compete and even reverse their contributions due to the anti-Stokes mechanism. The structure constants of molecular orbitals are extracted from numerical solutions to the Hartree-Fock equations. This approach correctly takes into account the exchange interaction. Quantum consideration of vibrational motion results in the occurrence of the critical vibrational state, the tunneling ionization from which has the maximum rate. The numbers of the critical vibrational states are different for different valence shells. In addition, quantum description of vibrations changes the rate of ionization from the ground vibrational state by 20%-40% in comparison with the quasiclassical results.
Relativistic Coulomb excitation of {sup 88}Kr
Energy Technology Data Exchange (ETDEWEB)
Moschner, Kevin; Blazhev, Andrey; Jolie, Jan; Warr, Nigel; Wendt, Andreas [IKP, Universitaet zu Koeln, 50937 Koeln (Germany); Collaboration: PreSPEC-Collaboration
2015-07-01
Within the scope of the PreSPEC campaign we performed a Coulomb-excitation experiment to determine absolute E2 transition strengths to 2{sup +} states in the radioactive nucleus {sup 88}Kr. The aim of our studies was to identify the one quadruple-phonon mixed-symmetry 2{sub MS}{sup +} state in order to extend our knowledge on these states to lighter N = 52 isotones and to track their evolution over different proton shells. The investigated ions were provided through projectile fission of a 650 MeV {sup 238}U beam on a primary target consisting of 0.6 g/cm{sup 2} {sup 9}Be and subsequent separation and identification of the reaction products via the FRS at GSI. The secondary target consisted of 0.4 g/cm{sup 2} {sup 197}Au. De-exciting γ radiation was detected by the PreSPEC array, consisting of 15 EUROBALL Cluster detectors. The Lund-York-Cologne-CAlorimeter LYCCA was used for particle identification after the secondary target. Absolute transition strengths of the transitions depopulating the 2{sup +}{sub 3} state in {sup 88}Kr which suggest the mixed symmetric character of this state are presented and discussed within the systematics of the N = 52 isotones.
Imaging Cracks by Laser Excited Thermography
Schlichting, J.; Kervalishvili, G. N.; Maierhofer, Ch.; Kreutzbruck, M.
2010-02-01
During the last years active thermography is increasingly used in a number of NDT problems in production and maintenance. In this work we focus on the detection of vertical cracks starting at the surface, which is an important indication of structural failure. By using local thermal excitation it is possible to image anisotropies in the lateral diffusivity by recording the temporal temperature data with an infrared camera. The regional transient behaviour of temperature distribution then can provide quantitative information of the crack parameter. In doing so, we present an advanced technique for the determination of the crack depth. The experimental set-up is based on an Nd:YAG laser. The beam is focused on the test sample by using an optical scanner to create the required lateral heat flow. The time resolved temperature distribution is recorded with an infrared camera (InSb FPA, 3 to 5 μm) providing a frame rate of up to 500 Hz. In addition we report on numerical simulation to investigate the concept of local heat excitation for a quantitative estimation of crack parameters. The modeling also includes the influence of surface to surface radiation inside the crack. We obtained a good consistency between experimental and theoretical data.
Force Sensor Characterization Under Sinusoidal Excitations
Directory of Open Access Journals (Sweden)
Nieves Medina
2014-10-01
Full Text Available The aim in the current work is the development of a method to characterize force sensors under sinusoidal excitations using a primary standard as the source of traceability. During this work the influence factors have been studied and a method to minimise their contributions, as well as the corrections to be performed under dynamic conditions have been established. These results will allow the realization of an adequate characterization of force sensors under sinusoidal excitations, which will be essential for its further proper use under dynamic conditions. The traceability of the sensor characterization is based in the direct definition of force as mass multiplied by acceleration. To do so, the sensor is loaded with different calibrated loads and is maintained under different sinusoidal accelerations by means of a vibration shaker system that is able to generate accelerations up to 100 m/s2 with frequencies from 5 Hz up to 2400 Hz. The acceleration is measured by means of a laser vibrometer with traceability to the units of time and length. A multiple channel data acquisition system is also required to simultaneously acquire the electrical output signals of the involved instrument in real time.
Collisional deactivation of highly vibrationally excited pyrazine
Miller, Laurie A.; Barker, John R.
1996-07-01
The collisional deactivation of vibrationally excited pyrazine (C4N2H4) in the electronic ground state by 19 collider gases was studied using the time-resolved infrared fluorescence (IRF) technique. The pyrazine was photoexcited with a 308 nm laser and its vibrational deactivation was monitored following rapid radiationless transitions to produce vibrationally excited molecules in the electronic ground state. The IRF data were analyzed by a simple approximate inversion method, as well as with full collisional master equation simulations. The average energies transferred in deactivating collisions (d) exhibit a near-linear dependence on vibrational energy at lower energies and less dependence at higher energies. The deactivation of ground state pyrazine was found to be similar to that of ground state benzene [J. R. Barker and B. M. Toselli, Int. Rev. Phys. Chem. 12, 305 (1990)], but it is strikingly different from the deactivation of triplet state pyrazine [T. J. Bevilacqua and R. B. Weisman, J. Chem. Phys. 98, 6316 (1993)].
Velocity Dispersion of Excited H2
Lacour, S; Hébrard, G; Oliveira, C; André, M K; Ferlet, R; Vidal-Madjar, A
2005-01-01
We present a study of the high rotational bands (J > 2) of H2 toward 4 early type galactic stars: HD 73882, HD 192639, HD 206267, and HD 207538. In each case, the velocity dispersion - characterized by the spectrum fitting parameter b - increases with the level of excitation, a phenomenon that has previously been detected by the Copernicus and IMAPS observatories. In particular, we show with 4 sigma confidence that for HD 192639 it is not possible to fit all J levels with a single b value, and that higher b values are needed for the higher levels. The amplitude of the line broadening, which can be as high as 10 km s^-1, makes explanations such as inhomogeneous spatial distribution unlikely. We investigate a mechanism in which the broadening is due to the molecules that are rotationally excited through the excess energy acquired after their formation on a grain (H2-formation pumping). We show that different dispersions would be a natural consequence of this mechanism. We note however that such process would re...
Electron Excitation of Tin and Tin ion
Sharma, Lalita; Srivastava, Rajesh
2014-05-01
There is a great requirement of accurate atomic data of tin and its ions to understand the properties of laser produced tin plasma, one of the sources of extreme ultraviolet (EUV) radiation. The constant efforts are being made under various international programs viz., International SEMATECH's EUV Source Program, Intel Lithography Roadmap etc., to improve the efficiency of the EUV sources which can meet the requirements of high volume manufacturing of commercial chips. For optimizing the efficiency of EUV device the plasma modeling should be accurate which in turn, would rely on the accuracy of atomic data used. In this connection we have undertaken the study of electron impact excitation of Sn and Sn+. Since the atomic number of Sn is 50, it is sufficiently heavy atom to manifest relativistic spin - orbit and exchange effects. Therefore, we have used a fully relativistic distorted wave (RDW) theory to calculate results for cross sections corresponding to various transitions as well as polarization of photons due to decay of excited states of Sn and Sn+ In our RDW theory wavefunctions for both, the target electrons and projectile electrons are obtained by solving Dirac equations. Thus the relativistic effects are incorporated in consistent manner to ensure the reliability of the cross section and polarization results which will be presented in detail at the conference. Department of Atomic Energy, Govt. of India (DAE-BRNS).
Morales, A. I.; Benzoni, G.; Watanabe, H.; Nishimura, S.; Browne, F.; Daido, R.; Doornenbal, P.; Fang, Y.; Lorusso, G.; Patel, Z.; Rice, S.; Sinclair, L.; Söderström, P.-A.; Sumikama, T.; Wu, J.; Xu, Z. Y.; Yagi, A.; Yokoyama, R.; Baba, H.; Avigo, R.; Bello Garrote, F. L.; Blasi, N.; Bracco, A.; Camera, F.; Ceruti, S.; Crespi, F. C. L.; de Angelis, G.; Delattre, M.-C.; Dombradi, Zs.; Gottardo, A.; Isobe, T.; Kojouharov, I.; Kurz, N.; Kuti, I.; Matsui, K.; Melon, B.; Mengoni, D.; Miyazaki, T.; Modamio-Hoyborg, V.; Momiyama, S.; Napoli, D. R.; Niikura, M.; Orlandi, R.; Sakurai, H.; Sahin, E.; Sohler, D.; Shaffner, H.; Taniuchi, R.; Taprogge, J.; Vajta, Zs.; Valiente-Dobón, J. J.; Wieland, O.; Yalcinkaya, M.
2016-03-01
Low-lying excited states in 72Ni have been investigated in an in-flight fission experiment at the RIBF facility of the RIKEN Nishina Center. The combination of the state-of-the-art BigRIPS and EURICA setups has allowed for a very accurate study of the β decay from 72Co to 72Ni, and has provided first experimental information on the decay sequence 72Fe→72Co→72Ni and on the delayed neutron-emission branch 73Co→72Ni . Accordingly, we report nearly 60 previously unobserved γ transitions which deexcite 21 new levels in 72Ni. Evidence for the location of the so-sought-after (42+) ,(62+) , and (81+) seniority states is provided. As well, the existence of a low-spin β -decaying isomer in odd-odd neutron-rich Co isotopes is confirmed for mass A =72 . The new experimental information is compared to simple shell-model calculations including only neutron excitations across the f p g shells. It is shown that, in general, the calculations reproduce well the observed states.
Study of beam-beam long range compensation with octupoles
Barranco Garcia, Javier; Buffat, Xavier; Tambasco, Claudia
2017-01-01
Long range beam-beam effects are responsible for particle losses and define fundamental operational parameters of colliders (i.e. crossing angles, intensities, emittances, ${\\beta}$${^∗}$). In this study we propose octuple magnets as a possible scheme to efficiently compensate long-range beam-beam interactions with a global correction scheme. The impact and improvements on the dynamic aperture of colliding beams together with estimates of the luminosity potentials are dis- cussed for the HL-LHC upgrade and extrapolations made for the FCC project.
Enhancement of octupole strength in near spherical nuclei
Energy Technology Data Exchange (ETDEWEB)
Robledo, L.M. [Universidad Autonoma de Madrid, Dep. Fisica Teorica, Facultad de Ciencias, Madrid (Spain)
2016-09-15
The validity of the rotational formula used to compute E1 and E3 transition strengths in even-even nuclei is analyzed within the Generator Coordinate Method framework based on mean field wave functions. It turns out that those nuclei with spherical or near spherical shapes the E1 and E3 strengths computed with this formula are strongly underestimated and a sound evaluation of them requires angular-momentum projected wave functions. Results for several isotopic chains with proton number equal to or near magic numbers are analyzed and compared with experimental data. The use of angular-momentum projected wave functions greatly improves the agreement with the scarce experimental data. (orig.)
DAFNE Lifetime Optimization with Octupoles and Compensating Wires
Milardi, C; Preger, M A; Raimondi, P; Zobov, M; Shatilov, D
2008-01-01
Long-range beam-beam interactions (parasitic crossings) were one of the main luminosity performance limitations for the lepton F-factory DAFNE in its original configuration. In particular, the parasitic crossings led to a substantial lifetime reduction of both beams in collision. This puts a limit on the maximum storable current and, as a consequence, on the achievable peak and integrated luminosity. In order to mitigate the problem, numerical and experimental studies of the parasitic crossings compensation by current-carrying wires have been done. During the operation for the KLOE experiment two such wires have been installed at both ends of the interaction region. They produced a relevant improvement in the lifetime of the weak beam (positrons) at the maximum current of the strong one (electrons) without luminosity loss, in agreement with the numerical predictions. The same compensating mechanism has been adopted during the run for the FINUDA experiment as well, with less evident benefits than in the previo...
Nonlinear Resonance of Mechanically Excited Sessile Drops
Chang, Chun-Ti; Daniel, Susan; Steen, Paul
2013-11-01
The spectrum of frequencies and mode shapes for an inviscid drop on a planar substrate have recently been documented. For vertical excitation, zonal modes respond to the driving frequency harmonically and non-zonal modes subharmonically, consistent with the prior literature. In this study, we report observations from the regime of nonlinear response. Here, zonals can respond non-harmonically, both sub- and super-harmonic responses are reported. The principal challenge to generating and observing superharmonic resonances of higher zonal modes is a mode-mixing behavior. However, using a simple visual simulation based on the ray-tracing technique, the individual contributions to the mixed resonance behavior can be extracted. In summary, results from experiment and theory show that the zonal modes, which respond harmonically and can mix with non-zonal modes without interfering with one another in the linear regime, tend to respond sub- or superharmonically and compete with non-zonal modes in the nonlinear regime.
Optimal excitation of two dimensional Holmboe instabilities
Constantinou, Navid C
2010-01-01
Highly stratified shear layers are rendered unstable even at high stratifications by Holmboe instabilities when the density stratification is concentrated in a small region of the shear layer. These instabilities may cause mixing in highly stratified environments. However these instabilities occur in tongues for a limited range of parameters. We perform Generalized Stability analysis of the two dimensional perturbation dynamics of an inviscid Boussinesq stratified shear layer and show that Holmboe instabilities at high Richardson numbers can be excited by their adjoints at amplitudes that are orders of magnitude larger than by introducing initially the unstable mode itself. We also determine the optimal growth that obtains for parameters for which there is no instability. We find that there is potential for large transient growth regardless of whether the background flow is exponentially stable or not and that the characteristic structure of the Holmboe instability asymptotically emerges for parameter values ...
Motor Skill Learning and Corticospinal Excitability
DEFF Research Database (Denmark)
Christiansen, Lasse
Background Motor skill learning (MSL) is the persistent increase in performance of a skill obtained through practice. This process is associated with changes throughout the central nervous system. One of these is a change in corticospinal excitability (CSE) assessable with Transcranial Magnetic...... Stimulation. Prior work has demonstrated such a change to very different extents with and without causally linking it to the improvements in motor performance. Objectives The aim of this PhD project has been to explore the relation between changes in CSE and motor performance over the time course of learning...... a novel visuomotor skill. I hypothesized that changes in CSE accompanying long-term motor practice relate to the process of learning rather than repetitive practice on an acquired skill and investigated this by incrementally increasing task difficulty and thus postponing saturation of learning...
Photonic simulation of topological excitations in metamaterials.
Tan, Wei; Sun, Yong; Chen, Hong; Shen, Shun-Qing
2014-01-23
Condensed matter systems with topological order and metamaterials with left-handed chirality have attracted recently extensive interests in the fields of physics and optics. So far the topological order and chirality of electromagnetic wave are two independent concepts, and there is no work to address their connection. Here we propose to establish the relation between the topological order in condensed matter systems and the chirality in metamaterials, by mapping explicitly Maxwell's equations to the Dirac equation in one dimension. We report an experimental implement of the band inversion in the Dirac equation, which accompanies change of chirality of electromagnetic wave in metamaterials, and the first microwave measurement of topological excitations and topological phases in one dimension. Our finding provides a proof-of-principle example that electromagnetic wave in the metamaterials can be used to simulate the topological order in condensed matter systems and quantum phenomena in relativistic quantum mechanics in a controlled laboratory environment.
Observation of excited $\\Lambda^0_b$ baryons
Aaij, R; Adametz, A; Adeva, B; Adinolfi, M; Adrover, C; Affolder, A; Ajaltouni, Z; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves Jr, A A; Amato, S; Amhis, Y; Anderson, J; Appleby, R B; Aquines Gutierrez, O; Archilli, F; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Bachmann, S; Back, J J; Balagura, V; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Bates, A; Bauer, C; Bauer, Th; Bay, A; Beddow, J; Bediaga, I; Belogurov, S; Belous, K; Belyaev, I; Ben-Haim, E; Benayoun, M; Bencivenni, G; Benson, S; Benton, J; Bernet, R; Bettler, M -O; van Beuzekom, M; Bien, A; Bifani, S; Bird, T; Bizzeti, A; Bjørnstad, P M; Blake, T; Blanc, F; Blanks, C; Blouw, J; Blusk, S; Bobrov, A; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borgia, A; Bowcock, T J V; Bozzi, C; Brambach, T; van den Brand, J; Bressieux, J; Brett, D; Britsch, M; Britton, T; Brook, N H; Brown, H; Büchler-Germann, A; Burducea, I; Bursche, A; Buytaert, J; Cadeddu, S; Callot, O; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carson, L; Carvalho Akiba, K; Casse, G; Cattaneo, M; Cauet, Ch; Charles, M; Charpentier, Ph; Chen, P; Chiapolini, N; Chrzaszcz, M; Ciba, K; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coca, C; Coco, V; Cogan, J; Cogneras, E; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombes, M; Corti, G; Couturier, B; Cowan, G A; Craik, D; Currie, R; D'Ambrosio, C; David, P; David, P N Y; De Bonis, I; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Simone, P; Decamp, D; Deckenhoff, M; Degaudenzi, H; Del Buono, L; Deplano, C; Derkach, D; Deschamps, O; Dettori, F; Dickens, J; Dijkstra, H; Diniz Batista, P; Domingo Bonal, F; Donleavy, S; Dordei, F; Dosil Suárez, A; Dossett, D; Dovbnya, A; Dupertuis, F; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Easo, S; Egede, U; Egorychev, V; Eidelman, S; van Eijk, D; Eisele, F; Eisenhardt, S; Ekelhof, R; Eklund, L; El Rifai, I; Elsasser, Ch; Elsby, D; Esperante Pereira, D; Falabella, A; Färber, C; Fardell, G; Farinelli, C; Farry, S; Fave, V; Fernandez Albor, V; Ferro-Luzzi, M; Filippov, S; Fitzpatrick, C; Fontana, M; Fontanelli, F; Forty, R; Francisco, O; Frank, M; Frei, C; Frosini, M; Furcas, S; Gallas Torreira, A; Galli, D; Gandelman, M; Gandini, P; Gao, Y; Garnier, J-C; Garofoli, J; Garra Tico, J; Garrido, L; Gascon, D; Gaspar, C; Gauld, R; Gauvin, N; Gersabeck, M; Gershon, T; Ghez, Ph; Gibson, V; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gordon, H; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graziani, G; Grecu, A; Greening, E; Gregson, S; Grünberg, O; Gui, B; Gushchin, E; Guz, Yu; Gys, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hampson, T; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; Harrison, P F; Hartmann, T; He, J; Heijne, V; Hennessy, K; Henrard, P; Hernando Morata, J A; van Herwijnen, E; Hicks, E; Hoballah, M; Hopchev, P; Hulsbergen, W; Hunt, P; Huse, T; Huston, R S; Hutchcroft, D; Hynds, D; Iakovenko, V; Ilten, P; Imong, J; Jacobsson, R; Jaeger, A; Jahjah Hussein, M; Jans, E; Jansen, F; Jaton, P; Jean-Marie, B; Jing, F; John, M; Johnson, D; Jones, C R; Jost, B; Kaballo, M; Kandybei, S; Karacson, M; Karbach, T M; Keaveney, J; Kenyon, I R; Kerzel, U; Ketel, T; Keune, A; Khanji, B; Kim, Y M; Knecht, M; Kochebina, O; Komarov, I; Koopman, R F; Koppenburg, P; Korolev, M; Kozlinskiy, A; Kravchuk, L; Kreplin, K; Kreps, M; Krocker, G; Krokovny, P; Kruse, F; Kruzelecki, K; Kucharczyk, M; Kudryavtsev, V; Kvaratskheliya, T; La Thi, V N; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lambert, R W; Lanciotti, E; Lanfranchi, G; Langenbruch, C; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J -P; Lefèvre, R; Leflat, A; Lefrançois, J; Leroy, O; Lesiak, T; Li, L; Li, Y; Li Gioi, L; Lieng, M; Liles, M; Lindner, R; Linn, C; Liu, B; Liu, G; von Loeben, J; Lopes, J H; Lopez Asamar, E; Lopez-March, N; Lu, H; Luisier, J; Mac Raighne, A; Machefert, F; Machikhiliyan, I V; Maciuc, F; Maev, O; Magnin, J; Malde, S; Mamunur, R M D; Manca, G; Mancinelli, G; Mangiafave, N; Marconi, U; Märki, R; Marks, J; Martellotti, G; Martens, A; Martin, L; Martín Sánchez, A; Martinelli, M; Martinez Santos, D; Massafferri, A; Mathe, Z; Matteuzzi, C; Matveev, M; Maurice, E; Maynard, B; Mazurov, A; McCarthy, J; McGregor, G; McNulty, R; Meissner, M; Merk, M; Merkel, J; Milanes, D A; Minard, M -N; Molina Rodriguez, J; Monteil, S; Moran, D; Morawski, P; Mountain, R; Mous, I; Muheim, F; Müller, K; Muresan, R; Muryn, B; Muster, B; Mylroie-Smith, J; Naik, P; Nakada, T; Nandakumar, R; Nasteva, I; Needham, M; Neufeld, N; Nguyen, A D; Nguyen-Mau, C; Nicol, M; Niess, V; Nikitin, N; Nikodem, T; Nomerotski, A; Novoselov, A; Oblakowska-Mucha, A; Obraztsov, V; Oggero, S; Ogilvy, S; Okhrimenko, O; Oldeman, R; Orlandea, M; Otalora Goicochea, J M; Owen, P; Pal, B K; Palacios, J; Palano, A; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Parkes, C; Parkinson, C J; Passaleva, G; Patel, G D; Patel, M; Patrick, G N; Patrignani, C; Pavel-Nicorescu, C; Pazos Alvarez, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perego, D L; Perez Trigo, E; Pérez-Calero Yzquierdo, A; Perret, P; Perrin-Terrin, M; Pessina, G; Petrolini, A; Phan, A; Picatoste Olloqui, E; Pie Valls, B; Pietrzyk, B; Pilař, T; Pinci, D; Plackett, R; Playfer, S; Plo Casasus, M; Polci, F; Polok, G; Poluektov, A; Polycarpo, E; Popov, D; Popovici, B; Potterat, C; Powell, A; Prisciandaro, J; Pugatch, V; Puig Navarro, A; Qian, W; Rademacker, J H; Rakotomiaramanana, B; Rangel, M S; Raniuk, I; Raven, G; Redford, S; Reid, M M; dos Reis, A C; Ricciardi, S; Richards, A; Rinnert, K; Roa Romero, D A; Robbe, P; Rodrigues, E; Rodrigues, F; Rodriguez Perez, P; Rogers, G J; Roiser, S; Romanovsky, V; Rosello, M; Rouvinet, J; Ruf, T; Ruiz, H; Sabatino, G; Saborido Silva, J J; Sagidova, N; Sail, P; Saitta, B; Salzmann, C; Sanmartin Sedes, B; Sannino, M; Santacesaria, R; Santamarina Rios, C; Santinelli, R; Santovetti, E; Sapunov, M; Sarti, A; Satriano, C; Satta, A; Savrie, M; Savrina, D; Schaack, P; Schiller, M; Schindler, H; Schleich, S; Schlupp, M; Schmelling, M; Schmidt, B; Schneider, O; Schopper, A; Schune, M -H; Schwemmer, R; Sciascia, B; Sciubba, A; Seco, M; Semennikov, A; Senderowska, K; Sepp, I; Serra, N; Serrano, J; Seyfert, P; Shapkin, M; Shapoval, I; Shatalov, P; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, O; Shevchenko, V; Shires, A; Silva Coutinho, R; Skwarnicki, T; Smith, N A; Smith, E; Smith, M; Sobczak, K; Soler, F J P; Solomin, A; Soomro, F; Souza, D; Souza De Paula, B; Spaan, B; Sparkes, A; Spradlin, P; Stagni, F; Stahl, S; Steinkamp, O; Stoica, S; Stone, S; Storaci, B; Straticiuc, M; Straumann, U; Subbiah, V K; Swientek, S; Szczekowski, M; Szczypka, P; Szumlak, T; T'Jampens, S; Teklishyn, M; Teodorescu, E; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Tolk, S; Topp-Joergensen, S; Torr, N; Tournefier, E; Tourneur, S; Tran, M T; Tsaregorodtsev, A; Tuning, N; Ubeda Garcia, M; Ukleja, A; Uwer, U; Vagnoni, V; Valenti, G; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; Velthuis, J J; Veltri, M; Vesterinen, M; Viaud, B; Videau, I; Vieira, D; Vilasis-Cardona, X; Visniakov, J; Vollhardt, A; Volyanskyy, D; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; Voss, H; Waldi, R; Wallace, R; Wandernoth, S; Wang, J; Ward, D R; Watson, N K; Webber, A D; Websdale, D; Whitehead, M; Wicht, J; Wiedner, D; Wiggers, L; Wilkinson, G; Williams, M P; Williams, M; Wilson, F F; Wishahi, J; Witek, M; Witzeling, W; Wotton, S A; Wright, S; Wu, S; Wyllie, K; Xie, Y; Xing, F; Xing, Z; Yang, Z; Young, R; Yuan, X; Yushchenko, O; Zangoli, M; Zavertyaev, M; Zhang, F; Zhang, L; Zhang, W C; Zhang, Y; Zhelezov, A; Zhong, L; Zvyagin, A
2012-01-01
Using $pp$ collision data corresponding to 1.0~fb^{-1} integrated luminosity collected by the LHCb detector, two narrow states are observed in the $\\Lambda_b^0\\pi^+\\pi^-$ spectrum with masses $5911.95\\pm 0.12(\\mbox{stat})\\pm 0.03(\\mbox{syst})\\pm 0.66(\\Lambda_b^0\\mbox{ mass})$ MeV/$c^2$ and $5919.76\\pm 0.07(\\mbox{stat})\\pm 0.02(\\mbox{syst})\\pm 0.66(\\Lambda_b^0\\mbox{ mass})$ MeV/$c^2$. The significances of the observations are 4.9 and 10.1 standard deviations, respectively. These states are interpreted as the orbitally-excited $\\Lambda_b^0$ baryons, $\\Lambda_b^{*0}(5912)$ and $\\Lambda_b^{*0}(5920)$.
Coded excitation for ultrasound tissue harmonic imaging.
Song, Jaehee; Kim, Sangwon; Sohn, Hak-Yeol; Song, Tai-Kyong; Yoo, Yang Mo
2010-05-01
Coded excitation can improve the signal-to-noise ratio (SNR) in ultrasound tissue harmonic imaging (THI). However, it could suffer from the increased sidelobe artifact caused by incomplete pulse compression due to the spectral overlap between the fundamental and harmonic components of ultrasound signal after nonlinear propagation in tissues. In this paper, three coded tissue harmonic imaging (CTHI) techniques based on bandpass filtering, power modulation and pulse inversion (i.e., CTHI-BF, CTHI-PM, and CTHI-PI) were evaluated by measuring the peak range sidelobe level (PRSL) with varying frequency bandwidths. From simulation and in vitro studies, the CTHI-PI outperforms the CTHI-BF and CTHI-PM methods in terms of the PRSL, e.g., -43.5dB vs. -24.8dB and -23.0dB, respectively. Copyright 2010 Elsevier B.V. All rights reserved.
Interchange mode excited by trapped energetic ions
Energy Technology Data Exchange (ETDEWEB)
Nishimura, Seiya, E-mail: n-seiya@kobe-kosen.ac.jp [Kobe City College of Technology, Kobe, Hyogo 651-2194 (Japan)
2015-07-15
The kinetic energy principle describing the interaction between ideal magnetohydrodynamic (MHD) modes with trapped energetic ions is revised. A model is proposed on the basis of the reduced ideal MHD equations for background plasmas and the bounce-averaged drift-kinetic equation for trapped energetic ions. The model is applicable to large-aspect-ratio toroidal devices. Specifically, the effect of trapped energetic ions on the interchange mode in helical systems is analyzed. Results show that the interchange mode is excited by trapped energetic ions, even if the equilibrium states are stable to the ideal interchange mode. The energetic-ion-induced branch of the interchange mode might be associated with the fishbone mode in helical systems.
Kisspeptin Excitation of GnRH Neurons
Rønnekleiv, Oline K.; Kelly, Martin J.
2014-01-01
Kisspeptin binding to its cognate G protein-coupled receptor (GPR54, aka Kiss1R) in gonadotropin-releasing hormone (GnRH) neurons stimulates peptide release and activation of the reproductive axis in mammals. Kisspeptin has pronounced pre- and postsynaptic effects, with the latter dominating the excitability of GnRH neurons. Presynaptically, kisspeptin increases the excitatory drive (both GABA-A and glutamate) to GnRH neurons and postsynaptically, kisspeptin inhibits an A-type and inwardly rectifying K + (Kir 6.2 and GIRK) currents and activates nonselective cation (TRPC) currents to cause long-lasting depolarization and increased action potential firing. The signaling cascades and the multiple intracellular targets of kisspeptin actions in native GnRH neurons are continuing to be elucidated. This review summarizes our current state of knowledge about kisspeptin signaling in GnRH neurons. PMID:23550004
Identification of excited states in conjugated polymers
Hartwell, L J
2003-01-01
This thesis reports quasi steady state photoinduced absorption measurements from three conjugated polymers: polypyridine (PPy), polyfluorene (PFO) and the emeraldine base (EB) form of polyaniline. The aim of these experiments was to determine the nature of the photoexcited states existing in these materials in the millisecond time domain, as this has important consequences for the operation of real devices manufactured using these materials. The results from the photoinduced absorption experiments are closely compared with published results from pulse radiolysis experiments. In all cases there is very good correspondence between the two data sets, which has enabled the photoexcited states to be assigned with a high degree of confidence. Quasi steady-state photoinduced absorption involves the measurement of the change in absorption of a material in response to optical excitation with a laser beam. The changes in absorption are small, so a instrument was developed and optimised for each different sample. Lock-i...
Theoretical description of nuclear collective excitations
Repko, Anton
2016-01-01
Density functional theory is a preferred microscopic method for calculation of nuclear properties over the whole nuclear chart. Besides ground-state properties, which are calculated by Hartree-Fock theory, nuclear excitations can be described by means of Random Phase Approximation (RPA). The main objective of the present work is to give Skyrme RPA formalism for spherically symmetric nuclei, using the techniques of angular-momentum coupling. Various auxiliary topics, such as Hartree-Fock theory, Coulomb integral, center-of-mass corrections and pairing, are treated as well. RPA method is derived also for axially deformed nuclei. The derived formulae are then implemented in the computer code and utilized for calculation of some physical results. After thorough investigation of the precision aspects of the calculation, the following topics are treated as examples: toroidal nature of the low-energy (pygmy) part of the E1 resonance, giant resonances of various multipolarities in deformed nucleus Sm-154, and magneti...
Radiative and Excited State Charmonium Physics
Energy Technology Data Exchange (ETDEWEB)
Jozef Dudek
2007-07-30
Renewed interest in the spectroscopy of charmonium has arisen from recent unexpected observations at $e^+e^-$ colliders. Here we report on a series of works from the previous two years examining the radiative physics of charmonium states as well as the mass spectrum of states of higher spin and internal excitation. Using new techniques applied to Domain-Wall and Clover quark actions on quenched isotropic and anisotropic lattices, radiative transitions and two-photon decays are considered for the first time. Comparisons are made with experimental results and with model approaches. Forthcoming application to the light-quark sector of relevance to experiments like Jefferson Lab's GlueX is discussed.
Enlarged Molecules from Excited Atoms in Nanochannels
Boström, Mathias; Sernelius, Bo E; Dou, Maofeng; Persson, Clas; Ninham, Barry W
2012-01-01
The resonance interaction that takes place in planar nanochannels between pairs of excited state atoms is explored. We consider interactions in channels of silica, zinc oxide and gold. The nanosized channels induce a dramatically different interaction from that in free space. Illustrative calculations for two lithium and cesium atoms, demonstrate that there is a short range repulsion followed by long range attraction. The binding energy is strongest near the surfaces. The size of the enlarged molecule is biggest at the center of the cavity and increases with channel width. Since the interaction is generic, we predict that enlarged molecules are formed in porous structures, and that the molecule size depends on the size of the nanochannels
Fission dynamics at low excitation energy. 2
Aritomo, Y; Ivanyuk, F A
2014-01-01
The mass asymmetry in the fission of U-236 at low excitation energy is clarified by the analysis of the trajectories obtained by solving the Langevin equations for the shape degrees of freedom. It is demonstrated that the position of the peaks in the mass distribution of fission fragments is determined mainly by the saddle point configuration originating from the shell correction energy. The width of the peaks, on the other hand, results from the shape fluctuations close to the scission point caused by the random force in the Langevin equation. We have found out that the fluctuations between elongated and compact shapes are essential for the fission process. According to our results the fission does not occur with continuous stretching in the prolate direction, similarly to that observed in starch syrup, but is accompanied by the fluctuations between elongated and compact shapes. This picture presents a new viewpoint of fission dynamics and the splitting mechanism.
Fission dynamics at low excitation energy
Aritomo, Y
2013-01-01
The origin of mass asymmetry in the fission of uranium at a low excitation energy is clarified by a trajectory analysis of the Langevin equation. The positions of the peaks in the mass distribution of fission fragments are mainly determined by fission saddle points originating from the shell correction energy. The widths of the peaks, on the other hand, result from a shape fluctuation around the scission point caused by the random force in the Langevin equation. We found that a random vibration in the oblate direction of fissioning fragments is essential for the fission process. According to this picture, fission does not occur with continuous stretching in the prolate direction, similarly to that observed in starch syrup. This is expected to lead to a new viewpoint of fission dynamics and the splitting mechanism.
Small massless excitations against a nontrivial background
Khariton, N. G.; Svetovoy, V. B.
1994-03-01
We propose a systematic approach for finding bosonic zero modes of nontrivial classical solutions in a gauge theory. The method allows us to find all the modes connected with the broken space-time and gauge symmetries. The ground state is supposed to be dependent on some space coordinates yα and independent of the rest of the coordinates xi. The main problem which is solved is how to construct the zero modes corresponding to the broken xiyα rotations in vacuum and which boundary conditions specify them. It is found that the rotational modes are typically singular at the origin or at infinity, but their energy remains finite. They behave as massless vector fields in x space. We analyze local and global symmetries affecting the zero modes. An algorithm for constructing the zero mode excitations is formulated. The main results are illustrated in the Abelian Higgs model with the string background.
The decay of highly excited open strings
Mitchell, D.; Turok, N.; Wilkinson, R.; Jetzer, P.
1988-01-01
The decay rates of leading edge Regge trajectory states are calculated for very high level number in open bosonic string theories, ignoring tachyon final states. The optical theorem simplifies the analysis while enabling identification of the different mass level decay channels. The main result is that (in four dimensions) the greatest single channel is the emission of a single photon and a state of the next mass level down. A simple asymptotic formula for arbitrarily high level number is given for this process. Also calculated is the total decay rate exactly up to N=100. It shows little variation over this range but appears to decrease for larger N. The formalism is checked in examples and the decay rate of the first excited level calculated for open superstring theories. The calculation may also have implications for high spin meson resonances.
Collisional excitation of water by hydrogen atoms
Daniel, F; Dagdigian, P J; Dubernet, M -L; lique, F; forêts, G Pineau des
2014-01-01
We present quantum dynamical calculations that describe the rotational excitation of H$_2$O due to collisions with H atoms. We used a recent, high accuracy potential energy surface, and solved the collisional dynamics with the close-coupling formalism, for total energies up to 12 000 cm$^{-1}$. From these calculations, we obtained collisional rate coefficients for the first 45 energy levels of both ortho- and para-H$_2$O and for temperatures in the range T = 5-1500 K. These rate coefficients are subsequently compared to the values previously published for the H$_2$O / He and H$_2$O / H$_2$ collisional systems. It is shown that no simple relation exists between the three systems and that specific calculations are thus mandatory.
Observation of Orbitally Excited Bs Mesons
Aaltonen, T.; Abulencia, A.; Adelman, J.; Akimoto, T.; Albrow, M. G.; Álvarez González, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Apresyan, A.; Arisawa, T.; Artikov, A.; Ashmanskas, W.; Attal, A.; Aurisano, A.; Azfar, F.; Azzi-Bacchetta, P.; Azzurri, P.; Bacchetta, N.; Badgett, W.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Baroiant, S.; Bartsch, V.; Bauer, G.; Beauchemin, P.-H.; Bedeschi, F.; Bednar, P.; Behari, S.; Bellettini, G.; Bellinger, J.; Belloni, A.; Benjamin, D.; Beretvas, A.; Beringer, J.; Berry, T.; Bhatti, A.; Binkley, M.; Bisello, D.; Bizjak, I.; Blair, R. E.; Blocker, C.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Boisvert, V.; Bolla, G.; Bolshov, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brau, B.; Brigliadori, L.; Bromberg, C.; Brubaker, E.; Budagov, J.; Budd, H. S.; Budd, S.; Burkett, K.; Busetto, G.; Bussey, P.; Buzatu, A.; Byrum, K. L.; Cabrera, S.; Campanelli, M.; Campbell, M.; Canelli, F.; Canepa, A.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Carron, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chang, S. H.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Chlebana, F.; Cho, K.; Chokheli, D.; Chou, J. P.; Choudalakis, G.; Chuang, S. H.; Chung, K.; Chung, W. H.; Chung, Y. S.; Ciobanu, C. I.; Ciocci, M. A.; Clark, A.; Clark, D.; Compostella, G.; Convery, M. E.; Conway, J.; Cooper, B.; Copic, K.; Cordelli, M.; Cortiana, G.; Crescioli, F.; Cuenca Almenar, C.; Cuevas, J.; Culbertson, R.; Cully, J. C.; Dagenhart, D.; Datta, M.; Davies, T.; de Barbaro, P.; de Cecco, S.; Deisher, A.; de Lentdecker, G.; de Lorenzo, G.; Dell'Orso, M.; Demortier, L.; Deng, J.; Deninno, M.; de Pedis, D.; Derwent, P. F.; di Giovanni, G. P.; Dionisi, C.; di Ruzza, B.; Dittmann, J. R.; D'Onofrio, M.; Donati, S.; Dong, P.; Donini, J.; Dorigo, T.; Dube, S.; Efron, J.; Erbacher, R.; Errede, D.; Errede, S.; Eusebi, R.; Fang, H. C.; Farrington, S.; Fedorko, W. T.; Feild, R. G.; Feindt, M.; Fernandez, J. P.; Ferrazza, C.; Field, R.; Flanagan, G.; Forrest, R.; Forrester, S.; Franklin, M.; Freeman, J. C.; Furic, I.; Gallinaro, M.; Galyardt, J.; Garberson, F.; Garcia, J. E.; Garfinkel, A. F.; Gerberich, H.; Gerdes, D.; Giagu, S.; Giannetti, P.; Gibson, K.; Gimmell, J. L.; Ginsburg, C. M.; Giokaris, N.; Giordani, M.; Giromini, P.; Giunta, M.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldschmidt, N.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gresele, A.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Grundler, U.; Guimaraes da Costa, J.; Gunay-Unalan, Z.; Haber, C.; Hahn, K.; Hahn, S. R.; Halkiadakis, E.; Hamilton, A.; Han, B.-Y.; Han, J. Y.; Handler, R.; Happacher, F.; Hara, K.; Hare, D.; Hare, M.; Harper, S.; Harr, R. F.; Harris, R. M.; Hartz, M.; Hatakeyama, K.; Hauser, J.; Hays, C.; Heck, M.; Heijboer, A.; Heinemann, B.; Heinrich, J.; Henderson, C.; Herndon, M.; Heuser, J.; Hewamanage, S.; Hidas, D.; Hill, C. S.; Hirschbuehl, D.; Hocker, A.; Hou, S.; Houlden, M.; Hsu, S.-C.; Huffman, B. T.; Hughes, R. E.; Husemann, U.; Huston, J.; Incandela, J.; Introzzi, G.; Iori, M.; Ivanov, A.; Iyutin, B.; James, E.; Jayatilaka, B.; Jeans, D.; Jeon, E. J.; Jindariani, S.; Johnson, W.; Jones, M.; Joo, K. K.; Jun, S. Y.; Jung, J. E.; Junk, T. R.; Kamon, T.; Kar, D.; Karchin, P. E.; Kato, Y.; Kephart, R.; Kerzel, U.; Khotilovich, V.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, J. E.; Kim, M. J.; Kim, S. B.; Kim, S. H.; Kim, Y. K.; Kimura, N.; Kirsch, L.; Klimenko, S.; Klute, M.; Knuteson, B.; Ko, B. R.; Koay, S. A.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Korytov, A.; Kotwal, A. V.; Kraus, J.; Kreps, M.; Kroll, J.; Krumnack, N.; Kruse, M.; Krutelyov, V.; Kubo, T.; Kuhlmann, S. E.; Kuhr, T.; Kulkarni, N. P.; Kusakabe, Y.; Kwang, S.; Laasanen, A. T.; Lai, S.; Lami, S.; Lammel, S.; Lancaster, M.; Lander, R. L.; Lannon, K.; Lath, A.; Latino, G.; Lazzizzera, I.; Lecompte, T.; Lee, J.; Lee, J.; Lee, Y. J.; Lee, S. W.; Lefèvre, R.; Leonardo, N.; Leone, S.; Levy, S.; Lewis, J. D.; Lin, C.; Lin, C. S.; Lindgren, M.; Lipeles, E.; Lister, A.; Litvintsev, D. O.; Liu, T.; Lockyer, N. S.; Loginov, A.; Loreti, M.; Lovas, L.; Lu, R.-S.; Lucchesi, D.; Lueck, J.; Luci, C.; Lujan, P.; Lukens, P.; Lungu, G.; Lyons, L.; Lys, J.; Lysak, R.; Lytken, E.; Mack, P.; MacQueen, D.; Madrak, R.; Maeshima, K.; Makhoul, K.; Maki, T.; Maksimovic, P.; Malde, S.; Malik, S.; Manca, G.; Manousakis, A.; Margaroli, F.; Marino, C.; Marino, C. P.; Martin, A.; Martin, M.; Martin, V.; Martínez, M.; Martínez-Ballarín, R.; Maruyama, T.; Mastrandrea, P.; Masubuchi, T.; Mattson, M. E.; Mazzanti, P.; McFarland, K. S.; McIntyre, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Menzemer, S.; Menzione, A.; Merkel, P.; Mesropian, C.; Messina, A.; Miao, T.; Miladinovic, N.; Miles, J.; Miller, R.; Mills, C.; Milnik, M.; Mitra, A.; Mitselmakher, G.; Miyake, H.; Moed, S.; Moggi, N.; Moon, C. S.; Moore, R.; Morello, M.; Movilla Fernandez, P.; Mülmenstädt, J.; Mukherjee, A.; Muller, Th.; Mumford, R.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Nagano, A.; Naganoma, J.; Nakamura, K.; Nakano, I.; Napier, A.; Necula, V.; Neu, C.; Neubauer, M. S.; Nielsen, J.; Nodulman, L.; Norman, M.; Norniella, O.; Nurse, E.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Oldeman, R.; Orava, R.; Osterberg, K.; Pagan Griso, S.; Pagliarone, C.; Palencia, E.; Papadimitriou, V.; Papaikonomou, A.; Paramonov, A. A.; Parks, B.; Pashapour, S.; Patrick, J.; Pauletta, G.; Paulini, M.; Paus, C.; Pellett, D. E.; Penzo, A.; Phillips, T. J.; Piacentino, G.; Piedra, J.; Pinera, L.; Pitts, K.; Plager, C.; Pondrom, L.; Portell, X.; Poukhov, O.; Pounder, N.; Prakoshyn, F.; Pronko, A.; Proudfoot, J.; Ptohos, F.; Punzi, G.; Pursley, J.; Rademacker, J.; Rahaman, A.; Ramakrishnan, V.; Ranjan, N.; Redondo, I.; Reisert, B.; Rekovic, V.; Renton, P.; Rescigno, M.; Richter, S.; Rimondi, F.; Ristori, L.; Robson, A.; Rodrigo, T.; Rogers, E.; Rolli, S.; Roser, R.; Rossi, M.; Rossin, R.; Roy, P.; Ruiz, A.; Russ, J.; Rusu, V.; Saarikko, H.; Safonov, A.; Sakumoto, W. K.; Salamanna, G.; Saltó, O.; Santi, L.; Sarkar, S.; Sartori, L.; Sato, K.; Savard, P.; Savoy-Navarro, A.; Scheidle, T.; Schlabach, P.; Schmidt, E. E.; Schmidt, M. A.; Schmidt, M. P.; Schmitt, M.; Schwarz, T.; Scodellaro, L.; Scott, A. L.; Scribano, A.; Scuri, F.; Sedov, A.; Seidel, S.; Seiya, Y.; Semenov, A.; Sexton-Kennedy, L.; Sfyrla, A.; Shalhout, S. Z.; Shapiro, M. D.; Shears, T.; Shepard, P. F.; Sherman, D.; Shimojima, M.; Shochet, M.; Shon, Y.; Shreyber, I.; Sidoti, A.; Sinervo, P.; Sisakyan, A.; Slaughter, A. J.; Slaunwhite, J.; Sliwa, K.; Smith, J. R.; Snider, F. D.; Snihur, R.; Soderberg, M.; Soha, A.; Somalwar, S.; Sorin, V.; Spalding, J.; Spinella, F.; Spreitzer, T.; Squillacioti, P.; Stanitzki, M.; St. Denis, R.; Stelzer, B.; Stelzer-Chilton, O.; Stentz, D.; Strologas, J.; Stuart, D.; Suh, J. S.; Sukhanov, A.; Sun, H.; Suslov, I.; Suzuki, T.; Taffard, A.; Takashima, R.; Takeuchi, Y.; Tanaka, R.; Tecchio, M.; Teng, P. K.; Terashi, K.; Thom, J.; Thompson, A. S.; Thompson, G. A.; Thomson, E.; Tipton, P.; Tiwari, V.; Tkaczyk, S.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Tourneur, S.; Trischuk, W.; Tu, Y.; Turini, N.; Ukegawa, F.; Uozumi, S.; Vallecorsa, S.; van Remortel, N.; Varganov, A.; Vataga, E.; Vázquez, F.; Velev, G.; Vellidis, C.; Veszpremi, V.; Vidal, M.; Vidal, R.; Vila, I.; Vilar, R.; Vine, T.; Vogel, M.; Volobouev, I.; Volpi, G.; Würthwein, F.; Wagner, P.; Wagner, R. G.; Wagner, R. L.; Wagner, J.; Wagner, W.; Wakisaka, T.; Wallny, R.; Wang, S. M.; Warburton, A.; Waters, D.; Weinberger, M.; Wester, W. C., III; Whitehouse, B.; Whiteson, D.; Wicklund, A. B.; Wicklund, E.; Williams, G.; Williams, H. H.; Wilson, P.; Winer, B. L.; Wittich, P.; Wolbers, S.; Wolfe, C.; Wright, T.; Wu, X.; Wynne, S. M.; Yagil, A.; Yamamoto, K.; Yamaoka, J.; Yamashita, T.; Yang, C.; Yang, U. K.; Yang, Y. C.; Yao, W. M.; Yeh, G. P.; Yoh, J.; Yorita, K.; Yoshida, T.; Yu, G. B.; Yu, I.; Yu, S. S.; Yun, J. C.; Zanello, L.; Zanetti, A.; Zaw, I.; Zhang, X.; Zheng, Y.; Zucchelli, S.
2008-02-01
We report the observation of two narrow resonances consistent with states of orbitally excited (L=1) Bs mesons using 1fb-1 of pp¯ collisions at s=1.96TeV collected with the Collider Detector at Fermilab II detector at the Fermilab Tevatron. We use two-body decays into K- and B+ mesons reconstructed as B+→J/ψK+, J/ψ→μ+μ- or B+→D¯0π+, D¯0→K+π-. We deduce the masses of the two states to be m(Bs1)=5829.4±0.7MeV/c2 and m(Bs2*)=5839.6±0.7MeV/c2.
Relaxed excited states of color centers
Energy Technology Data Exchange (ETDEWEB)
Baldacchini, G.
1992-12-31
Color centers in alkali halides display an optical cycle which has been, and it is still today, a model case for similar processes in other materials. Moreover, the luminescence of some color centers is so efficient that it has been used in laser applications. However, the quantum state from which the emission of light is originated, the so called relaxed excited state (RES), is not very well known. Indeed, in spite of the wealth of experimental results collected and of the theoretical approaches attempted, an exact description of the RES is still missing. This paper, confined mainly to F centers which are the simplest point defects in crystals, contains a review of the main experimental evidences which has some light on the nature of the RES, with special emphasis on the latest magneto-optical experiments. Also, a description of the theoretical models is attempted whenever required by a particular argument.
Motor Skill Learning and Corticospinal Excitability
DEFF Research Database (Denmark)
Christiansen, Lasse
Background Motor skill learning (MSL) is the persistent increase in performance of a skill obtained through practice. This process is associated with changes throughout the central nervous system. One of these is a change in corticospinal excitability (CSE) assessable with Transcranial Magnetic...... Stimulation. Prior work has demonstrated such a change to very different extents with and without causally linking it to the improvements in motor performance. Objectives The aim of this PhD project has been to explore the relation between changes in CSE and motor performance over the time course of learning...... a novel visuomotor skill. I hypothesized that changes in CSE accompanying long-term motor practice relate to the process of learning rather than repetitive practice on an acquired skill and investigated this by incrementally increasing task difficulty and thus postponing saturation of learning...
Dynamic range of hypercubic stochastic excitable media
de Assis, Vladimir R V
2007-01-01
We study the response properties of d-dimensional hypercubic excitable networks to a stochastic stimulus. Each site, modelled either by a three-state stochastic susceptible-infected-recovered-susceptible (SIRS) system or by the probabilistic Greenberg-Hastings cellular automaton (GHCA), is continuously and independently stimulated by an external Poisson rate h. The response function (mean density of active sites rho versus h) is obtained via simulations (for d=1, 2, 3, 4) and mean field approximations at the single-site and pair levels (for all d). In any dimension, the dynamic range of the response function is maximized precisely at the nonequilibrium phase transition to self-sustained activity, in agreement with a reasoning recently proposed. Moreover, the maximum dynamic range attained at a given dimension d is a decreasing function of d.
Holographic Construction of Excited CFT States
Christodoulou, Ariana
2016-01-01
We present a systematic construction of bulk solutions that are dual to CFT excited states. The bulk solution is constructed perturbatively in bulk fields. The linearised solution is universal and depends only on the conformal dimension of the primary operator that is associated with the state via the operator-state correspondence, while higher order terms depend on detailed properties of the operator, such as its OPE with itself and generally involve many bulk fields. We illustrate the discussion with the holographic construction of the universal part of the solution for states of two dimensional CFTs, either on $R \\times S^1$ or on $R^{1,1}$. We compute the 1-point function both in the CFT and in the bulk, finding exact agreement. We comment on the relation with other reconstruction approaches.
Chemotaxis to Excitable Waves in Dictyostelium Discoideum
Bhowmik, Arpan; Rappel, Wouter-Jan; Levine, Herbert
In recent years, there have been significant advances in our understanding of the mechanisms underlying chemically directed motility by eukaryotic cells such as Dictyostelium. In particular, the LEGI model has proven capable of providing a framework for quantitatively explaining many experiments that present Dictyostelium cells with tailored chemical stimuli and monitor their subsequent polarization. Here, we couple the LEGI approach to an excitable medium model of the cAMP wave-field that is self-generated by the cells and investigate the extent to which this class of models enables accurate chemotaxis to the cAMP waveforms expected in vivo. Our results indicate that the ultra-sensitive version of the model does an excellent job in providing natural wave rectification, thereby providing a compelling solution to the ``back-of-the-wave paradox'' during cellular aggregation. This work was supported by National Institutes of Health Grant P01 GM078586.
Laser-Induced Incandescence: Excitation Intensity
Vander Wal, Randall L.; Jensen, Kirk A.
1998-03-01
Assumptions of theoretical laser-induced incandescence (LII) models along with possible effects of high-intensity laser light on soot aggregates and the constituent primary particles are discussed in relation to selection of excitation laser fluence. Ex situ visualization of laser-heated soot by use of transmission electron microscopy reveals significant morphological changes (graphitization) induced by pulsed laser heating. Pulsed laser transmission measurements within a premixed laminar sooting flame suggest that soot vaporization occurs for laser fluences greater than 0.5 J cm 2 at 1064 nm. Radial LII intensity profiles at different axial heights in a laminar ethylene gas jet diffusion flame reveal a wide range of signal levels depending on the laser fluence that is varied over an eight fold range. Results of double-pulse excitation experiments in which a second laser pulse heats in situ the same soot that was heated by a prior laser pulse are detailed. These two-pulse measurements suggest varying degrees of soot structural change for fluences below and above a vaporization threshold of 0.5 J cm 2 at 1064 nm. Normalization of the radial-resolved LII signals based on integrated intensities, however, yields self-similar profiles. The self-similarity suggests robustness of LII for accurate relative measurement of soot volume fraction despite the morphological changes induced in the soot, variations in soot aggregate and primary particle size, and local gas temperature. Comparison of LII intensity profiles with soot volume fractions ( f v ) derived by light extinction validates LII for quantitative determination of f v upon calibration for laser fluences ranging from 0.09 to 0.73 J cm 2 .
Excited State Dynamics in Carbon Nanotubes
Miyamoto, Yoshiyuki
2004-03-01
Carbon nanotube, one of the most promising materials for nano-technology, still suffers from its imperfection in crystalline structure that will make performance of nanotube behind theoretical limit. From the first-principles simulations, I propose efficient methods to overcome the imperfection. I show that photo-induced ion dynamics can (1) identify defects in nanotubes, (2) stabilize defected nanotubes, and (3) purify contaminated nanotubes. All of these methods can be alternative to conventional heat treatments and will be important techniques for realizing nanotube-devices. Ion dynamics under electronic excitation has been simulated with use of the computer code FPSEID (First-Principles Simulation tool for Electron Ion Dynamics) [1], which combines the time-dependent density functional method [2] to classical molecular dynamics. This very challenging approach is time-consuming but can automatically treat the level alternation of differently occupied states, and can observe initiation of non-adiabatic decay of excitation. The time-dependent Kohn-Sham equation has been solved by using the Suzuki-Trotter split operator method [3], which is a numerically stable method being suitable for plane wave basis, non-local pseudopotentials, and parallel computing. This work has been done in collaboration with Prof. Angel Rubio, Prof. David Tomanek, Dr. Savas Berber and Mina Yoon. Most of present calculations have been done by using the SX5 Vector-Parallel system in the NEC Fuchu-plant, and the Earth Simulator in Yokohama Japan. [1] O. Sugino and Y. Miyamoto, Phys. Rev. B59, 2579 (1999); ibid, B66 089901(E) (2001) [2] E. Runge and E. K. U. Gross, Phys. Rev. Lett. 52, 997 (1984). [3] M. Suzuki, J. Phys. Soc. Jpn. 61, L3015 (1992).
A treatment of excited states in nucleosynthesis
Gupta, Sanjib Shankar
2002-10-01
Many isotopes of importance to nucleosynthesis have metastable states whose decay to the ground state is strongly inhibited by a high angular momentum difference. Traditionally, excited states of a nucleus have been treated by assuming attainment of thermal equilibrium; a Hauser-Feshbach calculation is then performed on the whole nucleus to determine nuclear reaction rates. A description of the nucleus when it is not in equilibrium, and a method for computing reaction rates that does not presume thermalization are presented in this work. In nucleosynthesis calculations, we may characterize the internal electromagnetic transitions of a nucleus as a Markov process. This allows us to decompose the interaction of radiation with nucleons into effective interactions between ensembles. Rather than consider a single isotope, we construct the canonical ensembles which are the true nuclear species of interest. We are then in a position to specify nonequilibrium occupations of the ensembles by discretizing the Nuclear Level Density function. The generality of the stochastic process identified at the outset now permits the description of nucleosynthesis as Markov flows in networks of suitably populated ensembles. This allows us to use as many excited states as we wish in nucleosyn thesis while tracking their nonequilibrium evolution as substochastic processes. A website utilizing these principles is discussed in some detail. It accesses the theoretical NLD database from the Brussels Intitute of Astrophysics to supplement adopted experimental data from the ENSDF database (maintained by Brookhaven National Laboratories). The composite is processed by a CGI (Common Gateway Interface) application to dynamically obtain plots and tables of rates on a specified temperature grid. Beta-decay rates are discussed for an isotope important to nuclear astrophysics ( 180TA) as a test-bed for the techniques implemented.
Excitation Spectrum in the Friedberg-Lee Model
Kowata, H.; Arima, M.
2001-03-01
The excitation spectrum of a nucleon with spin 1/2 is examined using the Friedberg-Lee model containing constituent quarks and a scalar meson. An appropriate method of quantization for the non-linear meson field is employed by taking account of the non-topological soliton existing at the classical level. Our model space for the nucleon resonances includes the three quark plus one meson state, in addition to the pure three quark state. The excitation spectrum in this model space reveals that the positive parity state appears as the first excited state associated with the 0s-excitation of the scalar meson. The meson excitation also generates an additional negative parity state apart from the well-known 0p-excitation of the quark.
Excitation Spectrum in the Friedberg-Lee Model
Kowata, H
2001-01-01
The excitation spectrum of the nucleon with the spin 1/2 is examined by using the Friedberg-Lee model containing the constituent quark and the scalar meson. An appropriate way of quantization for the non-linear meson field is employed by taking account of the non-topological soliton existed in the classical level. Our model space for the nucleon resonances includes the three-quark plus one-meson state in addition to the pure three-quark state. The excitation spectrum in this model space shows that the positive parity state appears as the first excited state associated with the 0s-excitation of the scalar meson. The meson excitation also generates the additional negative parity state apart from the well-known 0p-excitation of the quark.
Excitation spectrum in the Friedberg-Lee model
Energy Technology Data Exchange (ETDEWEB)
Kowata, Hiroto; Arima, Masaki [Department of Physics, Osaka City University, Osaka (Japan)
2001-03-01
The excitation spectrum of a nucleon with spin 1/2 is examined using the Friedberg-Lee model containing constituent quarks and a scalar meson. An appropriate method of quantization for the non-linear meson field is employed by taking account of the non-topological soliton existing at the classical level. Our model space for the nucleon resonances includes the three quark plus one meson state, in addition to the pure three quark state. The excitation spectrum in this model space reveals that the positive parity state appears as the first excited state associated with the 0s-excitation of the scalar meson. The meson excitation also generates an additional negative parity state apart from the well-known 0p-excitation of the quark. (author)
Systematics of α -decay transitions to excited states
Delion, D. S.; Dumitrescu, A.
2015-08-01
We systematize the available experimental material concerning α -decay transitions to low-lying excited states in even-even and odd-mass emitters. We generalize our previous theoretical prediction concerning the linear dependence between hindrance factors and the excitation energy for transitions in even-even α emitters. Thus, we show that α intensities for transitions to excited states depend linearly upon the excitation energy for all known even-even and odd-mass α emitters. It turns out that the well-known Viola-Seaborg law for α -decay transitions between ground states can be generalized for transitions to excited states. This rule can be used to predict any α -decay half-life to a low-lying excited state.
Excitation Dynamics and Relaxation in a Molecular Heterodimer
Balevicius, V; Abramavicius, D; Mancal, T; Valkunas, L
2011-01-01
The exciton dynamics in a molecular heterodimer is studied as a function of differences in excitation and reorganization energies, asymmetry in transition dipole moments and excited state lifetimes. The heterodimer is composed of two molecules modeled as two-level systems coupled by the resonance interaction. The system-bath coupling is taken into account as a modulating factor of the energy gap of the molecular excitation, while the relaxation to the ground state is treated phenomenologically. Comparison of the description of the excitation dynamics modeled using either the Redfield equations (secular and full forms) or the Hierarchical quantum master equation (HQME) is demonstrated and discussed. Possible role of the dimer as an excitation quenching center in photosynthesis self-regulation is discussed. It is concluded that the system-bath interaction rather than the excitonic effect determines the excitation quenching ability of such a dimer.
Searches for excited fermions in ep collisions at HERA
Abe, T; Adamczyk, L; Adamus, M; Aghuzumtsyan, G; Ahn, S H; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Bashkirov, V; Basile, M; Bauerdick, L A T; Bednarek, B; Behrens, U; Bell, M; Bellagamba, L; Benen, A; Bertolin, A; Bhadra, S; Bodmann, B; Bokel, C; Boogert, S; Boos, E G; Borras, K; Boscherini, D; Breitweg, J; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Cartiglia, N; Catterall, C D; Chapin, D; Chekanov, S; Chiochia, V; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cirio, R; Cloth, P; Coldewey, C; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cormack, C; Corradi, M; Corriveau, F; Costa, M; Crittenden, J; Cross, R; D'Agostini, Giulio; Dagan, S; Dal Corso, F; Danilov, P; Dannheim, D; De Pasquale, S; Dementiev, R K; Derrick, M; Deshpande, Abhay A; Desler, K; Devenish, R C E; Dhawan, S; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Engelen, J; Ermolov, P F; Eskreys, Andrzej; Ferrando, J; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fox-Murphy, A; Fricke, U; Fusayasu, T; Gabareen, A; Galea, R; Gallo, E; García, G; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Gilmore, J; Ginsburg, C M; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Göbel, F; Goers, S; Golubkov, Yu A; Goncalo, R; González, O; Göttlicher, P; Grabowska-Bold, I; Graciani, R; Grijpink, S; Grzelak, G; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hanlon, S; Hart, J C; Hartmann, H; Hartner, G F; Hayes, M E; Heaphy, E A; Heath, G P; Heath, H F; Helbich, M; Heusch, C A; Hilger, E; Hillert, S; Hirose, T; Hochman, D; Holm, U; Hughes, V W; Iacobucci, G; Iga, Y; Inuzuka, M; Irrgang, P; Jakob, H P; Jelen, K; Jeoung, H Y; Jones, T W; Kananov, S; Kappes, A; Karshon, U; Katkov, I I; Katz, U F; Kcira, D; Kerger, R; Khein, L A; Kim, C L; Kim, J Y; Kind, O; Kisielewska, D; Kitamura, S; Klimek, K; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korotkova, N A; Korzhavina, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowal, M; Kowalski, H; Kowalski, T; Krakauer, D; Kreisel, A; Kuze, M; Kuzmin, V A; Labarga, L; Labes, H; Lammers, S; Lane, J B; Lee, J H; Lee, S B; Lee, S W; Lelas, D; Levchenko, B B; Levi, G; Levman, G M; Levy, A; Lightwood, M S; Lim, H; Lim, I T; Limentani, S; Ling, T Y; Liu, X; Löhr, B; Lohrmann, E; Long, K R; Longhin, A; Lopez-Duran Viani, A; Lukina, O Yu; Lupi, A; Ma, K J; Maddox, E; Magill, S; Mankel, R; Margotti, A; Marini, G; Markun, P; Martens, J; Martin, J F; Martínez, M; Maselli, S; Massam, Thomas; Mastroberardino, A; Matsushita, T; Matsuzawa, K; Mattingly, M C K; McCubbin, N A; Mellado, B; Menary, S R; Metlica, F; Meyer, A; Milite, M; Miller, D B; Mindur, B; Mirea, A; Monaco, V; Moritz, M; Musgrave, B; Nagano, K; Nania, R; Nigro, A; Nishimura, T; Notz, D; Nowak, R J; Ochs, A; Oh, B Y; Olkiewicz, K; Pac, M Y; Padhi, S; Paganis, S; Palmonari, F; Parenti, A; Park, I H; Park, S K; Paul, E; Pavel, N; Pawlak, J M; Pelfer, P G; Pellegrino, A; Peroni, C; Pesci, A; Petrucci, M C; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Posocco, M; Proskuryakov, A S; Przybycien, M B; Raach, H; Rautenberg, J; Redondo, I; Reeder, D D; Renner, R; Repond, J; Rigby, M; Robins, S; Rodrigues, E; Rulikowska-Zarebska, E; Ruske, O; Ruspa, M; Sabetfakhri, A; Sacchi, R; Salehi, H; Sar, G; Saull, P R B; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schmidke, W B; Schneekloth, U; Schnurbusch, H; Sciulli, F; Scott, J; Selonke, F; Shche-, L M; Skillicorn, I O; Slominski, W; Smalska, B; Smith, W H; Soares, M; Solano, A; Solomin, A N; Son, D; Sosnovtsev, V V; Saint-Laurent, M G; Staiano, A; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Straub, P B; Suchkov, S; Surrow, B; Susinno, G; Suszycki, L; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tandler, J; Tapper, A D; Tapper, R J; Tassi, E; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Tuning, N; Turcato, M; Tymieniecka, T; Ukleja, A; Ukleja, J; Umemori, K; Vázquez, M; Velthuis, J J; Vlasov, N N; Voss, K C; Walczak, R; Walker, R; Weber, A; Wessoleck, H; West, B J; Whitmore, J J; Wichmann, R; Wick, K; Wiggers, L; Wills, H H; Wing, M; Wolf, G; Wölfle, S; Yamada, S; Yamashita, T; Yamazaki, Y; Yoshida, R; Youngman, C; Za, L; Zakrzewski, J A; Zeuner, W; Zhautykov, B O; Zichichi, A; Ziegler, A; Zotkin, S A; De Wolf, E; Del Peso, J
2002-01-01
Searches in ep collisions for heavy excited fermions have been performed with the ZEUS detector at HERA. Excited states of electrons and quarks have been searched for in e^+p collisions at a centre-of-mass energy of 300 GeV using an integrated luminosity of 47.7 pb^-1. Excited electrons have been sought via the decays e*->egamma, e*->eZ and e*->nuW. Excited quarks have been sought via the decays q*->qgamma and q*->qW. A search for excited neutrinos decaying via nu*->nugamma, nu*->nuZ and nu*->eW is presented using e^-p collisions at 318 GeV centre-of-mass energy, corresponding to an integrated luminosity of 16.7 pb^-1. No evidence for any excited fermion is found, and limits on the characteristic couplings are derived for masses below 250 GeV.
Excited electronic states and spectroscopy of unsymmetrically substituted polyenes
Itoh, Takao
2013-09-01
α-Methyl-ω-phenylpolyenes, Me-(CH=CH)N-Ph, (MPPNs) with N = 2, 3, and 4 were synthesized. Fluorescence, absorption, and excitation spectra of MPPNs have been measured under different conditions along with those of β-methylstyrene. It is shown that there is a forbidden singlet (π, π*) excited state located at energies below the absorbing state for MPPNs with N = 3 and 4. Excitation energies of these polyenes are determined as a function of N. Quantitative analysis of the temperature dependence of the relative intensity of the fluorescence spectrum and its solvent shift behavior extract estimates of the various physical parameters that characterize excitation energies and excited-state dynamical behavior of MPPN with N = 3. The singlet excited states of the MPPNs were compared with those of the α,ω-diphenylpolyenes and α,ω-dimethylpolyenes.
Modal Parameter Identification of Offshore Platforms under Ambient Excitation
Institute of Scientific and Technical Information of China (English)
Yang Hezhen(杨和振); Li Huajun
2004-01-01
This paper intends to identify the modal parameters of an offshore platform under ambient excitation, and to compare the identified results with theoretical solutions. Using ambient sources of excitation to determine the modal characteristics of large civil engineering structures is desirable for several reasons. The forced vibration testing of such structures generally requires a large amount of specialized equipment and makes the tests quite expensive. Also, an automated health monitoring system for a large civil structure will most likely use ambient excitation. The Eigensystem Realization Algorithm (ERA) is applied in conjunctied acceleration information. Finally, offshore platform numerical model gets output response data under ambient excitation. Simulated data from numerical model of an offshore platform under ambient excitation is used for the identification of the system. According to the comparison results, the proposed method is shown to be effective for modal parameter identification under ambient excitation.
Radiation damage in nonmetallic solids under dense electronic excitation
Energy Technology Data Exchange (ETDEWEB)
Itoh, Noriaki; Tanimura, Katsumi; Nakai, Yasuo (Dept. of Physics, Nagoya Univ. (Japan))
1992-03-01
Basic processes of radiation damage of insulators by dense electronic excitation are reviewed. First it is pointed out that electronic excitation of nonmetallic solids produces the self-trapped excitons and defect-related metastable states having relatively long lifetimes, and that the excitation of these metastable states, produces stable defects. The effects of irradiation with heavy ions, including track registration, are surveyed on the basis of the microscopic studies. It is pointed out also that the excitation of the metastable states plays a role in laser-induced damage at relatively low fluences, while the laser damage has been reported to be governed by heating of free electrons produced by multiphoton excitation. Difference in the contributions of the excitation of metastable defects to laser-induced damage of surfaces, or laser ablation, and laser-induced bulk damage is stressed. (orig.).
Search for excited charged leptons in electron positron collisions
Vachon, Brigitte Marie Christine; Sobie, Randall
2002-01-01
A search for evidence that fundamental particles are made of smaller subconstituents is performed. The existence of excited states of fundamental particles would be an unambiguous indication of their composite nature. Experimental signatures compatible with the production of excited states of charged leptons in electron-positron collisions are studied. The data analysed were collected by the OPAL detector at the LEP collider. No evidence for the existence of excited states of charged leptons was found. Upper limits on the product of the cross-section and the electromagnetic branching fraction are inferred. Using results from the search for singly produced excited leptons, upper limits on the ratio of the excited lepton coupling constant to the compositeness scale are calculated. From pair production searches, 95% confidence level lower limits on the masses of excited electrons, muons and taus are determined to be 103.2 GeV.
Representative Pathways of Excitation Migration in Photosystem I
Park, S; Lu, D; Schulten, K; Park, Sanghyun; Sener, Melih K.; Lu, Deyu; Schulten, Klaus
2002-01-01
Photosystem I is a protein-pigment complex that performs photosynthesis in plants, green algae, and cyanobacteria. It contains an aggregate of chlorophylls that absorbs light and delivers the resulting electronic excitation to the special pair of chlorophylls where the excitation energy is used for producing charge separation across the cell membrane. The seemingly random arrangement of chlorophylls in photosystem I poses the question which pathways excitation migration follows towards the special pair after absorption of light at any of its chlorophylls. We employ a master equation to describe the process of excitation migration in photosystem I, and find representative paths of excitation migration based on the mean first-passage time from each chlorophyll to the special pair. The resulting paths, beginning at each of the chlorophylls and ending at the special pair, provide a complete yet distilled picture of the excitation migration towards the special pair.
Effects of abnormal excitation on the dynamics of spiral waves
Min-Yi, Deng; Xue-Liang, Zhang; Jing-Yu, Dai
2016-01-01
The effect of physiological and pathological abnormal excitation of a myocyte on the spiral waves is investigated based on the cellular automaton model. When the excitability of the medium is high enough, the physiological abnormal excitation causes the spiral wave to meander irregularly and slowly. When the excitability of the medium is low enough, the physiological abnormal excitation leads to a new stable spiral wave. On the other hand, the pathological abnormal excitation destroys the spiral wave and results in the spatiotemporal chaos, which agrees with the clinical conclusion that the early after depolarization is the pro-arrhythmic mechanism of some anti-arrhythmic drugs. The mechanisms underlying these phenomena are analyzed. Project supported by the National Natural Science Foundation of China (Grant Nos. 11365003 and 11165004).
Synchronization of chaos in non-identical parametrically excited systems
Energy Technology Data Exchange (ETDEWEB)
Idowu, B.A. [Department of Physics, Lagos State University, Ojo (Nigeria)], E-mail: babaidowu@yahoo.com; Vincent, U.E. [Department of Physics, Olabisi Onabanjo University, P.M.B 2002, Ago-Iwoye (Nigeria)], E-mail: ue_vincent@yahoo.com; Njah, A.N. [Department of Physics, University of Agriculture, Abeokuta (Nigeria)
2009-03-15
In this paper, we investigate the synchronization of chaotic systems consisting of non-identical parametrically excited oscillators. The active control technique is employed to design control functions based on Lyapunov stability theory and Routh-Hurwitz criteria so as to achieve global chaos synchronization between a parametrically excited gyroscope and each of the parametrically excited pendulum and Duffing oscillator. Numerical simulations are implemented to verify the results.
Global synchronization of two parametrically excited systems using active control
Energy Technology Data Exchange (ETDEWEB)
Lei Youming [Department of Applied Mathematics, Northwestern Polytechnical University, Xi' an 710072 (China)] e-mail: leiyouming@nwpu.edu.cn; Xu Wei [Department of Applied Mathematics, Northwestern Polytechnical University, Xi' an 710072 (China)] e-mail: weixu@nwpu.edu.cn; Shen Jianwei [Department of Applied Mathematics, Northwestern Polytechnical University, Xi' an 710072 (China); Fang Tong [Department of Engineering Mechanics, Northwestern Polytechnical University, Xi' an 710072 (China)
2006-04-01
In this paper, we apply an active control technique to synchronize a kind of two parametrically excited chaotic systems. Based on Lyapunov stability theory and Routh-Hurwitz criteria, some generic sufficient conditions for global asymptotic synchronization are obtained. Illustrative examples on synchronization of two Duffing systems subject to a harmonic parametric excitation and that of two parametrically excited chaotic pendulums are considered here. Numerical simulations show the validity and feasibility of the proposed method.
Unidirectional mechanism for reentrant activity generation in excitable media.
Sendiña-Nadal, Irene; de Castro, Maite; Sagués, Francesc; Gómez-Gesteira, Moncho
2002-07-01
A closed excitable pathway with one point-to-point connection is used to generate a rotating wave both in experiments using the photosensitive Belousov-Zhabotinsky system and numerically with an Oregonator reaction-diffusion model. By varying the excitability and geometrical properties of the medium, propagation can be made unidirectional or bidirectional, giving rise, respectively, to the existence or not of sustained reentrant activity in a closed excitable track.
Recent questions about the excitation mechanism at intermediate velocity
Energy Technology Data Exchange (ETDEWEB)
Adoui, L.; Chabot, M.; Chetioui, A.; Despiney, I.; Guiraud, L.; L' Hoir, A.; Politis, M.F.; Rozet, J.P.; Schmaus, D.; Stephan, C.; Touati, A.; Vernhet, D.; Wohrer, K.; Cassimi, A.; Grandin, J.P.; Ramillon, J.M.; Macias, A.; Martin, F.; Riera, A.; Sanz, J.L.; Gayet, R. (G.P.S., Univ. Paris 7 et Paris 6, 75 Paris (France) CIRIL, 14 Caen (France) Dept. de Quimica, Faculdad de Ciencias, Univ. Autonoma de Madrid (Spain) Lab. des Collisions Atomiques, Univ. de Bordeaux 1, 33 Talence (France))
1994-04-01
For both fundamental reasons and potential applications, the process of K-excitation by heavy ions at intermediate velocity has been re-investigated experimentally and theoretically and the main results are described here. The nature and the origin of the so-called saturation effect'' at high exciting charge is not yet elucidated. The importance of K-excitation is outlined in connection with problems of radiation damage. (orig.)
How many atoms get excited when they decay?
Blocher, Philip Daniel; Mølmer, Klaus
2017-09-01
We analyse the time evolution of a two-level system prepared in a superposition of its ground state and radiatively unstable excited state. We show that by choosing appropriate means of detection of the radiated field, we can steer the evolution of the emitter and herald its preparation in the fully excited state. We determine the probability for the occurrence of this ‘excitation during the decay’ of a remote emitter.
Excited-State Effective Masses in Lattice QCD
Energy Technology Data Exchange (ETDEWEB)
George Fleming, Saul Cohen, Huey-Wen Lin
2009-10-01
We apply black-box methods, i.e. where the performance of the method does not depend upon initial guesses, to extract excited-state energies from Euclidean-time hadron correlation functions. In particular, we extend the widely used effective-mass method to incorporate multiple correlation functions and produce effective mass estimates for multiple excited states. In general, these excited-state effective masses will be determined by finding the roots of some polynomial. We demonstrate the method using sample lattice data to determine excited-state energies of the nucleon and compare the results to other energy-level finding techniques.
Ultra-short strong excitation of two-level systems
2013-01-01
We present a model describing the use of ultra-short strong pulses to control the population of the excited level of a two-level quantum system. In particular, we study an off-resonance excitation with a few cycles pulse which presents a smooth phase jump i.e. a change of the pulse's phase which is not step-like, but happens over a finite time interval. A numerical solution is given for the time-dependent probability amplitude of the excited level. The control of the excited level's populatio...
Search for Excited Quarks in ep Collisions at HERA
Aaron, F D; Alimujiang, K; Andreev, V; Antunovic, B; Asmone, A; Backovic, S; Baghdasaryan, A; Barrelet, E; Bartel, W; Begzsuren, K; Belousov, A; Bizot, J C; Boudry, V; Bozovic-Jelisavcic, I; Bracinik, J; Brandt, G; Brinkmann, M; Brisson, V; Bruncko, D; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Cassol-Brunner, F; Cerny, K; Cerny, V; Chekelian, V; Cholewa, A; Contreras, J G; Coughlan, J A; Cozzika, G; Cvach, J; Dainton, J B; Daum, K; Deak, M; de Boer, Y; Delcourt, B; Del Degan, M; Delvax, J; De Roeck, A; De Wolf, E A; Diaconu, C; Dodonov, V; Dossanov, A; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eliseev, A; Elsen, E; Falkiewicz, A; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Fischer, D J; Fleischer, M; Fomenko, A; Gabathuler, E; Gayler, J; Ghazaryan, S; Glazov, A; Glushkov, I; Goerlich, L; Gogitidze, N; Gouzevitch, M; Grab, C; Greenshaw, T; Grell, B R; Grindhammer, G; Habib, S; Haidt, D; Helebrant, C; Henderson, R C W; Hennekemper, E; Henschel, H; Herbst, M; Herrera, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R; Hreus, T; Jacquet, M; Janssen, M E; Janssen, X; Jemanov, V; Jonsson, L; Jung, Andreas Werner; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Kluge, T; Knutsson, A; Kogler, R; Korbel, V; Kostka, P; Kraemer, M; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Kruger, K; Kutak, K; Landon, M P J; Lange, W; Lastovicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Li, G; Lipka, K; Liptaj, A; List, B; List, J; Loktionova, N; Lopez-Fernandez, R; Lubimov, V; Lytkin, L; Makankine, A; Malinovski, E; Marage, P; Marti, Ll; Martyn, H U; Maxfield, S J; Mehta, A; Meyer, A B; Meyer, H; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Moreau, F; Morozov, A; Morris, J V; Mozer, Matthias Ulrich; Mudrinic, M; Muller, K; Murin, P; Naroska, B; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nowak, G; Nowak, K; Nozicka, M; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Pandurovic, M; Papadopoulou, Th; Pascaud, C; Patel, G D; Pejchal, O; Perez, E; Petrukhin, A; Picuric, I; Piec, S; Pitzl, D; Placakyte, R; Pokorny, B; Polifka, R; Povh, B; Preda, T; Radescu, V; Rahmat, A J; Raicevic, N; Raspiareza, A; Ravdandorj, T; Reimer, P; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rotaru, M; Ruiz Tabasco, J E; Rurikova, Z; Rusakov, S; Salek, D; Sankey, D P C; Sauter, M; Sauvan, E; Schmitt, S; Schmitz, C; Schoeffel, L; Schoning, A; Schultz-Coulon, H C; Sefkow, F; Shaw-West, R N; Sheviakov, I; Shtarkov, L N; Shushkevich, S; Sloan, T; Smiljanic, Ivan; Soloviev, Y; Sopicki, P; South, D; Spaskov, V; Specka, Arnd E; Staykova, Z; Steder, M; Stella, B; Stoicea, G; Straumann, U; Sunar, D; Sykora, T; Tchoulakov, V; Thompson, G; Thompson, P D; Toll, T; Tomasz, F; Tran, T H; Traynor, D; Trinh, T N; Truol, P; Tsakov, I; Tseepeldorj, B; Turnau, J; Urban, K; Valkarova, A; Vallee, C; Van Mechelen, P; Vargas Trevino, A; Vazdik, Y; Vinokurova, S; Volchinski, V; von den Driesch, M; Wegener, D; Wissing, Ch; Wunsch, E; Zacek, J; Zalesak, J; Zhang, Z; Zhokin, A; Zimmermann, T; Zohrabyan, H; Zomer, F; Zus, R
2009-01-01
A search for excited quarks is performed using the full ep data sample collected by the H1 experiment at HERA, corresponding to a total integrated luminosity of 475 pb^-1. The electroweak decays of excited quarks q* -> q gamma, q* -> q Z and q* -> q W with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for first generation excited quark production is found. Mass dependent exclusion limits on q* production cross sections and on the ratio f/Lambda of the coupling to the compositeness scale are derived within gauge mediated models. These limits extend the excluded region compared to previous excited quark searches.
Block 3 X-band receiver-exciter
Johns, C. E.
1987-01-01
The development of an X-band exciter, for use in the X-Band Uplink Subsystem, was completed. The exciter generates the drive signal for the X-band transmitter and also generates coherent test signals for the S- and X-band Block 3 translator and a Doppler reference signal for the Doppler extractor system. In addition to the above, the exciter generates other reference signals that are described. Also presented is an overview of the exciter design and some test data taken on the prototype. A brief discussion of the Block 3 Doppler extractor is presented.
Excited State Spectra and Dynamics of Phenyl-Substituted Butadienes
DEFF Research Database (Denmark)
Wallace-Williams, Stacie E.; Schwartz, Benjamin J.; Møller, Søren
1994-01-01
A combination of steady-state and dynamic spectral measurements are used to provide new insights into the nature of the excited-state processes of all-trans-1,4-diphenyl-1,3-butadiene and several analogs: 1,4-diphenyl- 1,3-cyclopentadiene, 1,1,4,4-tetraphenylbutadiene, 1,2,3,4-tetraphenyl-1,3-cyc...... indicate that phenyl torsional motion is not important to the excited-state dynamics and reveal alternative excited-state reaction pathways. The results demonstrate how molecular systems that are structually similar can exhibit different electronic properties and excited-state dynamics....
Percolation of optical excitation mediated by near-field interactions
Naruse, Makoto; Takahashi, Taiki; Aono, Masashi; Akahane, Kouichi; D'Acunto, Mario; Hori, Hirokazu; Thylen, Lars; Katori, Makoto; Ohtsu, Motoichi
2016-01-01
Optical excitation transfer in nanostructured matter has been intensively studied in various material systems for versatile applications. Herein, we discuss the percolation of optical excitations in randomly organized nanostructures caused by optical near-field interactions governed by Yukawa potential in a two-dimensional stochastic model. The model results demonstrate the appearance of two phases of percolation of optical excitation as a function of the localization degree of near-field interaction. Moreover, it indicates sublinear scaling with percolation distance when the light localization is strong. The results provide fundamental insights into optical excitation transfer and will facilitate the design and analysis of nanoscale signal-transfer characteristics.
Slow effects of fast harmonic excitation for elastic structures
DEFF Research Database (Denmark)
Tcherniak, Dmitri; Thomsen, Jon Juel
1998-01-01
High-frequency excitation may affect the 'slow' behavior of a dynamical system. For example, equilibria may move, disappear, or gain or loose stability. We consider such slow effects of fast excitation for a simple mechanical system that incorporates features of many engineering structures. The s....... The study is intended to contribute to the general understanding of periodically excited linear and nonlinear systems, as well as to the current attempts to utilize high-frequency excitation for altering the low-frequency properties of structures....
Analysis and Design of Hybrid Excitation Permanent Magnet Synchronous Generators
Institute of Scientific and Technical Information of China (English)
JIN Wan-bing; ZHANG Dong; AN Zhong-liang; TAN Ren-yuan
2006-01-01
On the basis of a conventional permanent magnet (PM) synchronous generator's construction,a novel kind of Hybrid Excitation Permanent Magnet Synchronous Generator (HEPMSG) is introduced by inserting exciting winding in the stator or rotor.Firstly,the construction of HEPMSG is improved with the addition of PM excitation on the ferromagnetic pole,and its working principle and design method are studied in detail.Then,an appropriate exciting current control system is presented considering the characteristics of HEPMSG.Finally,a prototype is made,and test results confirm the analysis and design.
Excitation dynamics and relaxation in a molecular heterodimer
Energy Technology Data Exchange (ETDEWEB)
Balevicius, V.; Gelzinis, A. [Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio Avenue 9, build. 3, LT-10222 Vilnius (Lithuania); Center for Physical Sciences and Technology, Institute of Physics, Savanoriu Avenue 231, LT-02300 Vilnius (Lithuania); Abramavicius, D. [Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio Avenue 9, build. 3, LT-10222 Vilnius (Lithuania); State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Mancal, T. [Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, CZ-121 16 Prague 2 (Czech Republic); Valkunas, L., E-mail: leonas.valkunas@ff.vu.lt [Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio Avenue 9, build. 3, LT-10222 Vilnius (Lithuania); Center for Physical Sciences and Technology, Institute of Physics, Savanoriu Avenue 231, LT-02300 Vilnius (Lithuania)
2012-08-24
Highlights: Black-Right-Pointing-Pointer Dynamics of excitation within a heterogenous molecular dimer. Black-Right-Pointing-Pointer Excited states can be swapped due to different reorganization energies of monomers. Black-Right-Pointing-Pointer Conventional excitonic basis becomes renormalized due to interaction with the bath. Black-Right-Pointing-Pointer Relaxation is independent of mutual positioning of monomeric excited states. -- Abstract: The exciton dynamics in a molecular heterodimer is studied as a function of differences in excitation and reorganization energies, asymmetry in transition dipole moments and excited state lifetimes. The heterodimer is composed of two molecules modeled as two-level systems coupled by the resonance interaction. The system-bath coupling is taken into account as a modulating factor of the molecular excitation energy gap, while the relaxation to the ground state is treated phenomenologically. Comparison of the description of the excitation dynamics modeled using either the Redfield equations (secular and full forms) or the Hierarchical quantum master equation (HQME) is demonstrated and discussed. Possible role of the dimer as an excitation quenching center in photosynthesis self-regulation is discussed. It is concluded that the system-bath interaction rather than the excitonic effect determines the excitation quenching ability of such a dimer.
Surface plasmon interference excited by tightly focused laser beams.
Energy Technology Data Exchange (ETDEWEB)
Bouhelier, A.; Ignatovich, F.; Bruyant, A.; Huang, C.; Colas des Francs, G.; Weeber, J.-C.; Dereux, A.; Wiederrecht, G. P.; Novotny, L.; Center for Nanoscale Materials; Univ de Bourgogne; Univ. of Rochester; Univ Technologique de Troyes
2007-09-01
We show that interfering surface plasmon polaritons can be excited with a focused laser beam at normal incidence to a plane metal film. No protrusions or holes are needed in this excitation scheme. Depending on the axial position of the focus, the intensity distribution on the metal surface is either dominated by interferences between counterpropagating plasmons or by a two-lobe pattern characteristic of localized surface plasmon excitation. Our experiments can be accurately explained by use of the angular spectrum representation and provide a simple means for locally exciting standing surface plasmon polaritons.
Simultaneous two-photon excitation of photodynamic therapy agents
Wachter, Eric A.; Partridge, W. P., Jr.; Fisher, Walter G.; Dees, Craig; Petersen, Mark G.
1998-07-01
The spectroscopic and photochemical properties of several photosensitive compounds are compared using conventional single-photon excitation (SPE) and simultaneous two-photon excitation (TPE). TPE is achieved using a mode-locked titanium:sapphire laser, the near infrared output of which allows direct promotion of non-resonant TPE. Excitation spectra and excited state properties of both type I and type II photodynamic therapy (PDT) agents are examined. In general, while SPE and TPE selection rules may be somewhat different, the excited state photochemical properties are equivalent for both modes of excitation. In vitro promotion of a two-photon photodynamic effect is demonstrated using bacterial and human breast cancer models. These results suggest that use of TPE may be beneficial for PDT, since the technique allows replacement of visible or ultraviolet excitation with non- damaging near infrared light. Further, a comparison of possible excitation sources for TPE indicates that the titanium:sapphire laser is exceptionally well suited for non- linear excitation of PDT agents in biological systems due to its extremely short pulse width and high repetition rate; these features combine to effect efficient PDT activation with minimal potential for non-specific biological damage.
Shape vibrations and quasiparticle excitations in the lowest 0+ excited state of the Erbium isotopes
Chen, Fang-Qi
2016-01-01
The ground and first excited 0+ states of the {156-172}Er isotopes are analyzed in the framework of the generator coordinate method. The shape parameter beta is used to generate wave functions with different deformations which together with the two-quasiparticle states built on them provide a set of states. An angular momentum and particle number projection of the latter spawn the basis states of the generator coordinate method. With this ansatz and using the separable pairing plus quadrupole interaction we obtain a good agreement with the experimental spectra and E2 transition rates up to moderate spin values. The structure of the wave functions suggests that the first excited 0+ states in the soft Er isotopes are dominated by shape fluctuations, while in the well deformed Er isotopes the two-quasiparticle states are more relevant. In between both degrees of freedom are necessary .
Nonlinear Dynamical Analysis for the Cable Excited with Parametric and Forced Excitation
Directory of Open Access Journals (Sweden)
C. Z. Qian
2014-01-01
Full Text Available Considering the deck vibration effect on the cable in cable-stayed bridge, using nonlinear structure dynamics theory, the nonlinear dynamical equation for the stayed cable excited with deck vibration is proposed. Research shows that the vertical vibration of the deck has a combined parametric and forced excitation effect on the cable when the angle of the cable is taken into consideration. Using multiscale method, the 1/2 principle parametric resonance is studied and the bifurcation equation is obtained. Despite the parameters analysis, the bifurcation characters of the dynamical system are studied. At last, by means of numerical method and software MATHMATIC, the effect rules of system parameters to the dynamical behavior of the system are studied, and some useful conclusions are obtained.
Excitation-wavelength dependence of multiphoton excitation of fluorophores of human skin in vivo
Breunig, Hans Georg; Studier, Hauke; König, Karsten
2010-02-01
We present in vivo measurements of the excitation-wavelength dependence of the autofluorescence of major endogenous fluorophores of human skin with a multiphoton tomograph. For the investigation high-resolution multiphoton images at different depths inside the skin were recorded and the main fluorophores identified. In particular, for the autofluorescence of the fluorophores keratin, NAD(P)H, elastin and for the second-harmonic-generation light induced by collagen fibers clear trends are shown.
Excitation of gases with positive ions
Energy Technology Data Exchange (ETDEWEB)
Sercel, P.C.; Bashkin, S.; Anderson, J.A.; Thiede, D.A.; Bruch, R.F.; DeWitt, D.; Fuelling, S.
1988-04-01
The aurora borealis presents problems the solutions to which depend partly on knowing the cross sections for the excitation of states in atmospheric gases by the impact of energetic protons and electrons. We have begun a study of the excitation processes induced in N/sub 2/ and O/sub 2/ by energetic incident positive ions (H/sup +/, H/sub 2//sup +/, H/sub 3//sup +/). The particles, accelerated with a 2 MV Van de Graaff accelerator, enter a differentially pumped gas cell in which the pressure can be varied up to 80 mTorr and held constant to 0.1 mTorr at each setting. Light generated in the cell is observed at 90/sup 0/ to the particle beam. The light is reflected by a mirror system so as to enter the input slit of a 1-m, air, Czerny-Turner spectrometer. The 1200 l/mm grating is blazed at 500 nm. A cooled 9659B photomultiplier tube detects the light which appears at the exit slit, and transmits intensity information to a 4000-channel multiscaler. The incident beam is received on an insulated plate, and the collected charge provides a signal which advances both the grating angle and the channel in the multiscaler. Using a line width of 0.03 to 0.1 nm, we have obtained spectra from 360 to 750 nm. Many transitions have been identified, most from N/sub 2//sup +/ O/sub 2//sup -/, but some from neutral molecules and monatomic emitters. Data have been taken as a function of pressure and type of incident particle for a particle velocity corresponding to 500 keV protons. There is no discernible difference in relative yield for the different bombarding species. The line intensities all appear to be linear with pressure over the range we used. We will describe our results and discuss our approach to making cross-section measurements. Possible extensions of the experiments into different directions will also be mentioned.