Average radiation widths and the giant dipole resonance width
Arnould, M.; Thielemann, F.K.
1982-11-01
The average E1 radiation width can be calculated in terms of the energy Esub(G) and width GAMMAsub(G) of the Giant Dipole Resonance (GDR). While various models can predict Esub(G) quite reliably, the theoretical situation regarding ..lambda..sub(G) is much less satisfactory. We propose a simple phenomenological model which is able to provide GAMMAsub(G) values in good agreement with experimental data for spherical or deformed intermediate and heavy nuclei. In particular, this model can account for shell effects in GAMMAsub(G), and can be used in conjunction with the droplet model. The GAMMAsub(G) values derived in such a way are used to compute average E1 radiation widths which are quite close to the experimental values. The method proposed for the calculation of GAMMAsub(G) also appears to be well suited when the GDR characteristics of extended sets of nuclei are required, as is namely the case in nuclear astrophysics.
Temperature Dependence of Spreading Width of Giant Dipole Resonance
Storozhenko, A N; Ventura, A; Blokhin, A I
2002-01-01
The Quasiparticle-Phonon Nuclear Model extended to finite temperature within the framework of Thermo Field Dynamics is applied to calculate a temperature dependence of the spreading width Gamma^{\\downarrow} of a giant dipole resonance. Numerical calculations are made for ^{120}Sn and ^{208}Pb nuclei. It is found that Gamma^{\\downarrow} increases with T. The reason of this effect is discussed as well as a relation of the present approach to other ones, existing in the literature.
Excitation-energy dependence of the giant dipole resonance width
Enders, G.; Berg, F. D.; Hagel, K.; Kühn, W.; Metag, V.; Novotny, R.; Pfeiffer, M.; Schwalb, O.; Charity, R. J.; Gobbi, A.; Freifelder, R.; Henning, W.; Hildenbrand, K. D.; Holzmann, R.; Mayer, R. S.; Simon, R. S.; Wessels, J. P.; Casini, G.; Olmi, A.; Stefanini, A. A.
1992-07-01
High-energy γ rays have been measured in coincidence with heavy fragents in deeply inelastic reactions of 136Xe+48Ti at 18.5 MeV/nucleon. The giant dipole resonance (GDR) strength function is deduced from an analysis of the photon spectra within the statistical model. The GDR width Γ is studied as a function of the fragment excitation energy E*. A saturation at about Γ=10 MeV is observed for E*/A>=1.0 MeV/nucleon.
Excitation-energy dependence of the giant dipole resonance width
Enders, G.; Berg, F.D.; Hagel, K.; Kuehn, W.; Metag, V.; Novotny, R.; Pfeiffer, M.; Schwalb, O. (II. Physikalisches Institut, Universitaet, Giessen, Giessen (Germany)); Charity, R.J.; Gobbi, A.; Freifelder, R.; Henning, W.; Hildenbrand, K.D.; Holzmann, R.; Mayer, R.S.; Simon, R.S.; Wessels, J.P. (Gesellschaft fuer Schwerionenforschung Darmstadt, Darmstadt (Germany)); Casini, G.; Olmi, A.; Stefanini, A.A. (Istituto Nazionale di Fisica Nucleare and University of Florence, Florence (Italy))
1992-07-13
High-energy {gamma} rays have been measured in coincidence with heavy fragents in deeply inelastic reactions of {sup 136}Xe+{sup 48}Ti at 18.5 MeV/nucleon. The giant dipole resonance (GDR) strength function is deduced from an analysis of the photon spectra within the statistical model. The GDR width {Gamma} is studied as a function of the fragment excitation energy {ital E}{sup *}. A saturation at about {Gamma}=10 MeV is observed for {ital E}{sup *}/{ital A}{ge}1.0 MeV/nucleon.
Temperature dependence of a spreading width of giant dipole resonance in neutron-rich nuclei
Vdovin, A.I.; Storozhenko, A.N
2003-07-14
A temperature dependence of the spreading width of a giant dipole resonance is studied in the framework of the Quasiparticle-Phonon Model extended to finite temperature using a formalism of the Thermo Field Dynamics. Numerical calculations are performed for {sup 120}Sn and the neutron-rich double-magic isotope {sup 132}Sn It is found that the dispersion of the E1 strength function {sigma} increases with temperature.
Measurement of Giant Dipole Resonance width at low temperature: A new experimental perspective
Mukhopadhyay, S; Pal, Surajit; Bhattacharya, Srijit; De, A; Bhattacharya, S; Bhattacharya, C; Banerjee, K; Kundu, S; Rana, T K; Mukherjee, G; Pandey, R; Gohil, M; Pai, H; Meena, J K; Banerjee, S R
2011-01-01
The systematic evolution of the giant dipole resonance (GDR) width in the temperature region of 0.9 ~ 1.4 MeV has been measured experimentally for 119Sb using alpha induced fusion reaction and employing the LAMBDA high energy photon spectrometer. The temperatures have been precisely determined by simultaneously extracting the vital level density parameter from the neutron evaporation spectrum and the angular momentum from gamma multiplicity filter using a realistic approach. The systematic trend of the data seems to disagree with the thermal shape fluctuation model (TSFM). The model predicts the gradual increase of GDR width from its ground state value for T > 0 MeV whereas the measured GDR widths appear to remain constant at the ground state value till T ~ 1 MeV and increase thereafter indicating towards a failure of the adiabatic assumption of the model at low temperature.
Temperature dependence of the giant dipole resonance width in 152Gd
Ghosh, C.; Mishra, G.; Rhine Kumar, A. K.; Dokania, N.; Nanal, V.; Pillay, R. G.; Kumar, Suresh; Rout, P. C.; Joshi, Sandeep; Arumugam, P.
2016-07-01
To investigate the dependence of giant dipole resonance (GDR) width on temperature (T ) and angular momentum (J ), high energy γ -ray spectra were measured in the reaction 28Si+124Sn at E28Si=135 MeV. The J information was deduced from multiplicity of low-energy γ rays. The GDR parameters, namely, the centroid energy and width are extracted using statistical model analysis. The observed variation of the GDR width for T ˜1.2 -1.37 MeV and J ˜20 ℏ -40 ℏ is consistent with the universal scaling given by Kusnezov et al., which is applicable in the liquid-drop regime. The GDR input cross sections extracted from the statistical model best fits are compared with thermal shape fluctuation model (TSFM) calculations and are found to be in good agreement. The TSFM calculations predominantly favor the noncollective oblate shape, while the statistical model fit with both prolate and oblate shapes describes the data. The present data together with earlier measurements indicate a very slow variation of the GDR width for T ˜1.2 to 1.5 MeV. The observed trend is well explained by the TSFM calculations, although the calculated values are ˜4 %-13% higher than the data.
Evolution of giant dipole resonance width at low temperatures – New perspectives
S Mukhopadhyay
2014-05-01
High energy photons from the decay of giant dipole resonances (GDR) built on excited states provide an excellent probe in the study of nuclear structure properties, damping mechanisms etc., at finite temperatures. The dependence of GDR width on temperature () and angular momentum () has been the prime focus of many experimental and theoretical studies for the last few decades. The measured GDR widths for a wide range of nuclei at temperatures (1.5 < < 2.5 MeV) and spins (upto fission limit) were well described by the thermal shape fluctuation model (TSFM). But, at low temperatures ( < 1.5 MeV) there are large discrepancies between the existing theoretical models. The problem is compounded as there are very few experimental data in this region. At Variable Energy Cyclotron Centre, Kolkata, a programme for the systematic measurement of GDR width at very low temperatures has been initiated with precise experimental techniques. Several experiments have been performed by bombarding 7–12 MeV/nucleon alpha beam on various targets (63Cu, 115In and 197Au) and new datasets have been obtained at low temperatures ( < 1.5MeV) and at very lowspins ( < 20$\\hbar$). The TSFM completely fails to represent the experimental data at these low temperatures in the entire mass range. In fact, the GDR width appears to be constant at its ground state value until a critical temperature is reached and subsequently increases thereafter, whereas the TSFM predicts a gradual increase of GDR width from its ground state value for > 0 MeV. In order to explain this discrepancy at low , a new formalism has been put forward by including GDR-induced quadrupole moment in the TSFM.
Decay Properties Of The Dipole Isobaric Analog Resonances
Gorelik, M. L.; Safonov, I. V.; Urin, M. H.
2006-01-01
Abstract: A continuum-RPA-based approach is applied to describe the decay properties of isolated dipole isobaric analog resonances in nuclei having not-too-large neutron excess. Calculated for a few resonances in 90Zr the elastic E1-radiative width and partial proton widths for decay into one-hole s
Giant dipole resonance in hot rotating nuclei
Chakrabarty, D.R. [Bhabha Atomic Research Centre, Nuclear Physics Division, Mumbai (India); Dinh Dang, N. [RIKEN, Nishina Centre for Accelerator-based Science, Saitama (Japan); VINATOM, Institute of Nuclear Science and Technique, Hanoi (Viet Nam); Datar, V.M. [Tata Institute of Fundamental Research, INO Cell, Mumbai (India)
2016-05-15
Over the last several decades, extensive experimental and theoretical work has been done on the giant dipole resonance (GDR) in excited nuclei covering a wide range of temperature (T), angular momentum (J) and nuclear mass. A reasonable stability of the GDR centroid energy and an increase of the GDR width with T (in the range∝1-3 MeV) and J are the two well-established results. Some experiments have indicated the saturation of the GDR width at high T. The gradual disappearance of the GDR vibration at much higher T has been observed. Experiments on the Jacobi transition and the GDR built on superdeformed shapes at high rotational frequencies have been reported in a few cases. Theoretical calculations on the damping of the collective dipole vibration, characterised by the GDR width, have been carried out within various models such as the thermal shape fluctuation model and the phonon damping model. These models offer different interpretations of the variation of the GDR width with T and J and have met with varying degrees of success in explaining the experimental data. In this review, the present experimental and theoretical status in this field is discussed along with the future outlook. The interesting phenomenon of the pre-equilibrium GDR excitation in nuclear reactions is briefly addressed. (orig.)
Pygmy dipole resonance and dipole polarizability in 90Zr
Iwamoto, C.; Tamii, A.; Utsunomiya, H.; Akimune, H.; Nakada, H.; Shima, T.; Hashimoto, T.; Yamagata, T.; Kawabata, T.; Fujita, Y.; Matsubara, H.; Suzuki, T.; Fujita, H.; Shimbara, Y.; Nagashima, M.; Sakuda, M.; Mori, T.; Izumi, T.; Okamoto, A.; Kondo, T.; Lui, T.-W.; Bilgier, B.; Kozer, H. C.; Hatanaka, K.
2014-05-01
Electric dipole (E1) reduced transition probability B(E1) of 90Zr was obtained by the inelastic proton scattering near 0 degrees using a 295 MeV proton beam and multipole decomposition analysis of the angular distribution by the distorted-wave Born approximation with the Hartree-Fock plus random-phase approximation model and inclusion of El Coulomb excitation, and the E1 strength of the pygmy dipole resonance was found in the vicinity of the neutron threshold in the low-energy tail of the giant dipole resonance. Using the data, we plan to determine the precise dipole polarizability αD which is defined as an inversely energy-weighted sum value of the elecrric dipole strength. The dipole polarizability is expected to constrain the symmetry energy term of the neutron matter equation of state. Thus systematical measurement of the dipole polarizability is important.
Pygmy dipole resonance and dipole polarizability in {sup 90}Zr
Iwamoto, C.; Tamii, A.; Shima, T.; Hashimoto, T.; Suzuki, T.; Fujita, H.; Hatanaka, K. [Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Utsunomiya, H.; Akimune, H.; Yamagata, T.; Okamoto, A.; Kondo, T. [Department of Physics, Konan University, Okamoto 8-9-1, Higashinada, Kobe 658-8501 (Japan); Nakada, H. [Department of Physics, Graduate School of Science, Chiba University, Yayoi-cho 1-33, Inage, Chiba 263-8522 (Japan); Kawabata, T. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Fujita, Y. [Department of Physics, Osaka University, Toyonaka, Osaka, 560-0043 (Japan); Matsubara, H. [RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan); Shimbara, Y.; Nagashima, M. [Department of Physics, Niigata University, Niigata 950-21-2 (Japan); Sakuda, M.; Mori, T. [Department of Physics, Okayama University, Okayama 900-0082 (Japan); and others
2014-05-02
Electric dipole (E1) reduced transition probability B(E1) of {sup 90}Zr was obtained by the inelastic proton scattering near 0 degrees using a 295 MeV proton beam and multipole decomposition analysis of the angular distribution by the distorted-wave Born approximation with the Hartree-Fock plus random-phase approximation model and inclusion of El Coulomb excitation, and the E1 strength of the pygmy dipole resonance was found in the vicinity of the neutron threshold in the low-energy tail of the giant dipole resonance. Using the data, we plan to determine the precise dipole polarizability α{sub D} which is defined as an inversely energy-weighted sum value of the elecrric dipole strength. The dipole polarizability is expected to constrain the symmetry energy term of the neutron matter equation of state. Thus systematical measurement of the dipole polarizability is important.
Splitting of the Dipole and Spin Dipole Resonances in Pb
Austin, Sam M.
2000-10-01
The response to different neutrino flavors of a supernova neutrino detector based on Pb depends on the position of the spin-dipole resonance(Fuller, Fowler and McLaughlin, Phys. Rev. D59,085005(1999)). In this talk I will present a phenomenolgical model that allows one to extract the splitting of the dipole and spin-dipole resonances from the variation with bombarding energy of the L=1 resonance in (p,n) reactions. This model has been applied previously to the Zr isotopes (Sam M. Austin, Phys. Rev. C, submitted). The dipole splitting for ^208Pb is determined from available data on the (p,n) reaction for bombarding energies between 45 to 200 MeV. It is found to be 4.7±2.0 MeV, with the spin-dipole resonance lying at lower excitation energy.
Thermal pairing and giant dipole resonance in highly excited nuclei
Dang, Nguyen Dinh
2014-01-01
Recent results are reported showing the effects of thermal pairing in highly excited nuclei. It is demonstrated that thermal pairing included in the phonon damping model (PDM) is responsible for the nearly constant width of the giant dipole resonance (GDR) at low temperature $T $ 170 MeV.
Experimental results on the Pygmy Dipole Resonance
Savran Deniz
2014-03-01
Full Text Available The so-called Pygmy Dipole Resonance, an additional structure of low-lying electric dipole strength, has attracted strong interest in the last years. Different experimental approaches have been used in the last decade in order to investigate this new interesting nuclear excitation mode. In this contribution an overview on the available experimental data is given.
Pygmy dipole resonance in stable nuclei
P Von Neumann-Cosel
2010-07-01
Two examples of recent work on the structure of low-energy electric dipole modes are presented. The first part discusses the systematics of the pygmy dipole resonance (PDR) in stable tin isotopes deduced from high-resolution (, ′) experiments. These help to distinguish between microscopic QRPA calculations based on either a relativistic or a non-relativistic mean-field description, predicting significantly different properties of the PDR. The second part presents a novel approach to measure the complete electric dipole strength distribution from excitation energies starting at about 5 MeV across the giant dipole resonance (GDR) with high-resolution inelastic proton scattering under 0° at energies of a few 100 MeV/nucleon. The case of 208Pb is discussed in detail and first result from a recent experiment on 120Sn is presented.
Masses, widths, and leptonic widths of the higher upsilon resonances
Lovelock, D.M.J.; Horstkotte, J.E.; Klopfenstein, C.; Lee-Franzini, J.; Romero, L.; Schamberger, R.D.; Youssef, S.; Franzini, P.; Son, D.; Tuts, P.M.
1985-02-04
The masses, total widths, and leptonic widths of three triplet s-wave bb-bar states UPSILON(4S), UPSILON(5S), and UPSILON(6S) are determined from measurements of the e/sup +/e/sup -/ annihilation cross section into hadrons for 10.55
Anharmonic effects and double giant dipole resonances
Voronov, V V
2001-01-01
A brief review of recent results of the microscopic calculations to describe characteristics of the double giant dipole resonances (DGDR) is presented. A special attention is paid to a microscopic study of the anharmonic properties of the DGDR. It is found that the deviation of the energy centroid of the DGDR from the harmonic limit follows A sup - sup 1 dependence
Resonance trapping and saturation of decay widths
Persson, E; Rotter, I
1998-01-01
Resonance trapping appears in open many-particle quantum systems at high level density when the coupling to the continuum of decay channels reaches a critical strength. Here a reorganization of the system takes place and a separation of different time scales appears. We investigate it under the influence of additional weakly coupled channels as well as by taking into account the real part of the coupling term between system and continuum. We observe a saturation of the mean width of the trapped states. Also the decay rates saturate as a function of the coupling strength. The mechanism of the saturation is studied in detail. In any case, the critical region of reorganization is enlarged. When the transmission coefficients for the different channels are different, the width distribution is broadened as compared to a chi_K^2 distribution where K is the number of channels. Resonance trapping takes place before the broad state overlaps regions beyond the extension of the spectrum of the closed system.
Pygmy dipole resonance in 208Pb
Poltoratska, I; Tamii, A; Adachi, T; Bertulani, C A; Carter, J; Dozono, M; Fujita, H; Fujita, K; Fujita, Y; Hatanaka, K; Itoh, M; Kawabata, T; Kalmykov, Y; Krumbholz, A M; Litvinova, E; Matsubara, H; Nakanishi, K; Neveling, R; Okamura, H; Ong, H J; Özel-Tashenov, B; Ponomarev, V Yu; Richter, A; Rubio, B; Sakaguchi, H; Sakemi, Y; Sasamoto, Y; Shimbara, Y; Shimizu, Y; Smit, F D; Suzuki, T; Tameshige, Y; Wambach, J; Yosoi, M; Zenihiro, J
2012-01-01
Scattering of protons of several hundred MeV is a promising new spectroscopic tool for the study of electric dipole strength in nuclei. A case study of 208Pb shows that at very forward angles J^pi = 1- states are strongly populated via Coulomb excitation. A separation from nuclear excitation of other modes is achieved by a multipole decomposition analysis of the experimental cross sections based on theoretical angular distributions calculated within the quasiparticle-phonon model. The B(E1) transition strength distribution is extracted for excitation energies up to 9 MeV, i.e., in the region of the so-called pygmy dipole resonance (PDR). The Coulomb-nuclear interference shows sensitivity to the underlying structure of the E1 transitions, which allows for the first time an experimental extraction of the strength and energy centroid of the PDR.
Double giant dipole resonance in hot nuclei
Cinausero, M.; Rizzi, V.; Viesti, G.; Fabris, D.; Lunardon, M.; Moretto, S.; Nebbia, G.; Pesente, S.; Barbui, M.; Fioretto, E.; Prete, G.; Bracco, A.; Camera, F.; Million, B.; Leoni, S.; Wieland, O.; Benzoni, G.; Brambilla, S.; Airoldi, A.; Maj, A.; Kmiecik, M
2004-02-09
Signals from Double Dipole Giant Resonances (DGDR) in hot nuclei have been searched in a {gamma}-{gamma} coincidence experiment using the HECTOR array at the Laboratori Nazionali di Legnaro. The experimental single {gamma}-ray spectrum and the projection of the {gamma}-{gamma} matrix have been compared with a standard Monte Carlo Statistical Model code including only the single GDR excitation. These calculations have been used as background to determine the extra-yield associated with the DGDR de-excitation. Results have been compared with a previous experiment confirming the presence of the DGDR excitation in fusion-evaporation reactions.
Spin dipole and quadrupole resonances in sup 40 Ca
Baker, F.T.; Love, W.G. (The University of Georgia, Athens, GA (USA)); Bimbot, L. (The University of Paris, Orsay, (France)); Fergerson, R.W.; Glashausser, C.; Green, A. (Rutgers University, New Brunswick, NJ (USA)); Jones, K. (Los Alamos National Laboratory, Los Alamos, NM (USA)); Nanda, S. (Continuous Electron Beam Accelerator Facility, Newport News, VA (USA) The University of Georgia, Athens, GA (USA))
1989-11-01
Angular distributions of the double differential cross section {ital d}{sup 2}{sigma}/d{Omega} dE({sigma}) and the spin-flip probability {ital S}{sub {ital nn}} have been measured for inclusive proton inelastic scattering from {sup 40}Ca at 319 MeV. Excitation energies ({omega}) up to about 40 MeV have been investigated over the angular range from 3.5{degree} to 12{degree} in the laboratory (0.3 to 0.9 fm{sup {minus}1}). Here, multipole decompositions of angular distributions of {sigma}{ital S}{sub {ital nn}} for the {sup 40}Ca({ital {rvec p}},{ital {rvec p}} {prime}) reaction at 319 MeV have been performed in order to compare {Delta}{ital S}=1 strength observed with sum rules. In contrast to the well-known quenching of Gamow-Teller and {ital M}1 resonances, the spin-dipole resonance has a total measured strength which is larger than that predicted by the energy-weighted sum rule. The spin-dipole strength distribution supports asymmetric widths predicted by calculations including 2p-2h mixing. The spin-quadrupole resonance is observed near {omega}=35 MeV and its total strength for {omega}{lt}40 MeV estimated.
Giant dipole resonance studied with GASP
Cinausero, M. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Bazzacco, D. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Bortignon, P.F. [Dipartimento di Fisica, I.N.F.N., Sezione di Milano, 20133, Milano (Italy); De Angelis, G. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Fabris, D. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Fiore, E.M. [Dipartimento di Fisica, I.N.F.N., Sezione di Bari, 70126, Bari (Italy); Fiore, L. [Dipartimento di Fisica, I.N.F.N., Sezione di Bari, 70126, Bari (Italy); Fioretto, E. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Fornal, B. [Institute of Nuclear Physics, 31342, Cracow (Poland); Gelli, N. [Dipartimento di Fisica, I.N.F.N., Sezione di Firenze, 50125, Firenze (Italy); Lops, M. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Lucarelli, F. [Dipartimento di Fisica, I.N.F.N., Sezione di Firenze, 50125, Firenze (Italy); Lunardi, S. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Nebbia, G. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Paticchio, V. [Dipartimento di Fisica, I.N.F.N., Sezione di Bari, 70126, Bari (Italy); Prete, G. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Rossi-Alvarez, C. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Viesti, G. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy)
1996-03-18
The giant dipole resonance (GDR) from the decay of excited {sup 156}Er nuclei populated in the reaction {sup 64}Ni+{sup 92}Zr at 241 MeV has been studied by using the GASP spectrometer. High-energy {gamma}-ray spectra have been obtained in coincidence with the 80 elements of the GASP inner ball and with discrete transitions in the residual nuclei {sup 155,154}Er. GDR parameters extracted from the high-energy {gamma}-ray spectra in coincidence with low-energy {gamma}-ray fold k>10 are in good agreement with systematics as well as with predictions from adiabatic calculations. No signature for entrance channel effects in the decay of {sup 156}Er was therefore observed from this lineshape analysis of the high-energy {gamma}-ray spectra in contrast with the case of the {sup 164}Yb nucleus. (orig.).
Deuteron spin-flip resonance widths and the spin response function
S. R. Mane
2007-11-01
Full Text Available The spin response function is used to analyze the spin-flip resonance widths of stored polarized deuteron beams. It is found, using simple model assumptions, that the contribution of the vertical betatron oscillations (for an rf radial dipole field spin-flipper reduces the resonance width by an amount in good agreement with recent measurements. It is also noted that, for spin-flip measurements with an rf-solenoid spin flipper, the spin response formalism also yields an answer consistent with experimental data.
Probing eigenfunction nonorthogonality by parametric shifts of resonance widths
Savin, D V
2013-01-01
Recently, it has been shown that the change of resonance widths in an open system under a perturbation of its interior is a sensitive indicator of the nonorthogonality of resonance states. We apply this measure to quantify parametric motion of the resonances. In particular, a strong redistribution of the widths is linked with the maximal degree of nonorthogonality. Then for weakly open chaotic systems we discuss the role of spectral rigidity on the statistical properties of the parametric width shifts, and derive the distribution of the latter in a picket-fence model with equidistant spectrum.
Plasmon-Induced Resonant Energy Transfer: a coherent dipole-dipole coupling mechanism
Bristow, Alan D.; Cushing, Scott K.; Li, Jiangtian; Wu, Nianqiang
Metal-insulator-semiconductor core-shell nanoparticles have been used to demonstrate a dipole-dipole coupling mechanism that is entirely dependent on the dephasing time of the localized plasmonic resonance. Consequently, the short-time scale of the plasmons leads to broad energy uncertainty that allows for excitation of charge carriers in the semiconductor via stimulation of photons with energies below the energy band gap. In addition, this coherent energy transfer process overcomes interfacial losses often associated with direct charge transfer. This work explores the efficiency of the energy transfer process, the dipole-dipole coupling strength with dipole separation, shell thickness and plasmonic resonance overlap. We demonstrate limits where the coherent nature of the coupling is switched off and charge transfer processes can dominate. Experiments are performed using transient absorption spectroscopy. Results are compared to calculations using a quantum master equation. These nanostructures show strong potential for improving solar light-harvesting for power and fuel generation.
Structure of the pygmy dipole resonance in Sn-124
Endres, J.; Savran, D.; Butler, P. A.; Harakeh, M. N.; Harissopulos, S.; Herzberg, R. -D.; Kruecken, R.; Lagoyannis, A.; Litvinova, E.; Pietralla, N.; Ponomarev, V. Yu.; Popescu, L.; Ring, P.; Scheck, M.; Schlueter, F.; Sonnabend, K.; Stoica, V. I.; Zilges, A.; Wortche, Heinrich
2012-01-01
Background: In atomic nuclei, a concentration of electric dipole strength around the particle threshold, commonly denoted as pygmy dipole resonance, may have a significant impact on nuclear structure properties and astrophysical scenarios. A clear identification of these states and the structure of
CROSSING A COUPLING SPIN RESONANCE WITH AN RF DIPOLE.
BAI,M.; ROSER,T.
2001-06-18
In accelerators, due to quadrupole roll errors and solenoid fields, the polarized proton acceleration often encounters coupling spin resonances. In the Brookhaven AGS, the coupling effect comes from the solenoid partial snake which is used to overcome imperfection resonances. The coupling spin resonance strength is proportional to the amount of coupling as well as the strength of the corresponding intrinsic spin resonance. The coupling resonance can cause substantial beam polarization loss if its corresponding intrinsic spin resonance is very strong. A new method of using an horizontal rf dipole to induce a full spin flip crossing both the intrinsic and its coupling spin resonances is studied in the Brookhaven's AGS. Numerical simulations show that a full spin flip can be induced after crossing the two resonances by using a horizontal rf dipole to induce a large vertical coherent oscillation.
Resonances and dipole moments in dielectric, magnetic, and magnetodielectric cylinders
Dirksen, A.; Arslanagic, Samel; Breinbjerg, Olav
2011-01-01
An eigenfunction solution to the problem of plane wave scattering by dielectric, magnetic, and magnetodielectric cylinders is used for a systematic investigation of their resonances. An overview of the resonances with electric and magnetic dipole moments, needed in, e.g., the synthesis...... of metamaterials, is given with an emphasis on their strength, bandwidth, and isolation....
Electric and magnetic dipole couplings in split ring resonator metamaterials
Fan Jing; Sun Guang-Yong; and Zhu Wei-Ren
2011-01-01
In this paper,the electric and the magnetic dipole couplings between the outer and the inner rings of a single split ring resonator (SRR) are investigated.We numerically demonstrate that the magnetic resonance frequency can be substantially modified by changing the couplings of the electric and magnetic dipoles,and give a theoretical expression of the magnetic resonance frequency.The results in this work are expected to be conducive to a deeper understanding of the SRR and other similar metamaterials,and provide new guidance for complex metamaterials design with a tailored electromagnetic response.
Damping Mechanism of the Giant Dipole Resonance in Hot Nuclei with A=130
Wieland, O.; Bracco, A.; Camera, F.; Benzoni, G.; Blasi, N.; Crespi, F. C. L.; Leoni, S.; Million, B.; Barlini, S.; Kravchuk, V. L.; Gramegna, F.; Lanchais, A.; Maj, A.; Kmiecik, M.; Casini, G.; Chiari, M.; Nannini, A.; Bruno, M.; Geraci, E.
2007-04-01
The gamma decay of the Giant Dipole Resonance (GDR) in 132Ce nuclei has been measured using the reactions 64Ni (Elab= 300, 400, 500 MeV) + 68Zn and 16O (Elab= 130,250 MeV) + 116Sn. The analysis of the data shows clearly that the GDR width increases steadily with temperature at least up to 4 MeV of the temperature. The data can be well interpreted within the thermal shape fluctuation model.
Campione, Salvatore; Warne, Larry K; Sinclair, Michael B
2014-01-01
In this paper we describe a methodology for tailoring the design of metamaterial dielectric resonators, which represent a promising path toward low-loss metamaterials at optical frequencies. We first describe a procedure to decompose the far field scattered by subwavelength resonators in terms of multipolar field components, providing explicit expressions for the multipolar far fields. We apply this formulation to confirm that an isolated high-permittivity cube resonator possesses frequency separated electric and magnetic dipole resonances, as well as a magnetic quadrupole resonance in close proximity to the electric dipole resonance. We then introduce multiple dielectric gaps to the resonator geometry in a manner suggested by perturbation theory, and demonstrate the ability to overlap the electric and magnetic dipole resonances, thereby enabling directional scattering by satisfying the first Kerker condition. We further demonstrate the ability to push the quadrupole resonance away from the degenerate dipole ...
Magnetic dipole interaction and line widths in NQR: 35Cl NQR spectrum of chloroform
Subramanian, V. Harihara; Narasimhan, P. T.
35 Cl NQR spectra of CHC1 3 and CDCl 3 have been recorded at 77 K with an injection and phase-locked NQR spectrometer. The theoretical 35Cl NQR spectrum of CHC1 3 has been computed with the inclusion of H-C1 intramolecular magnetic dipole Interaction In the quadrupole Hamiltonian. It has been possible to obtain the H-C1 internuclear distance in the CHC1 3 molecule by assuming that contributions to 35Cl NQR line width from static electric effects and relaxation effects are the same in CHC1 3 and CDCl 3 and that the magnetic dipole interaction contribution to 35Cl NQR line width in CDCl 3 is negligible. The calculated H-C1 distance values are: 2.34 Å for the 'a' site and 2.49 Å for the 'b' site. These values may be compared with the x-ray value of 2.31 Å. It has also been possible to assign the observed NQR frequencies to the appropriate chlorine sites in the unit cell.
Resonance widths in open microwave cavities studied by harmonic inversion
Kuhl, U; Hoehmann, R.; Main, J.; Stoeckmann, H. -J.
2007-01-01
From the measurement of a reflection spectrum of an open microwave cavity the poles of the scattering matrix in the complex plane have been determined. The resonances have been extracted by means of the harmonic inversion method. By this it became possible to resolve the resonances in a regime where the line widths exceed the mean level spacing up to a factor of 10, a value inaccessible in experiments up to now. The obtained experimental distributions of line widths were found to be in perfec...
Beam induced electron cloud resonances in dipole magnetic fields
Calvey, J. R.; Hartung, W.; Makita, J.; Venturini, M.
2016-07-01
The buildup of low energy electrons in an accelerator, known as electron cloud, can be severely detrimental to machine performance. Under certain beam conditions, the beam can become resonant with the cloud dynamics, accelerating the buildup of electrons. This paper will examine two such effects: multipacting resonances, in which the cloud development time is resonant with the bunch spacing, and cyclotron resonances, in which the cyclotron period of electrons in a magnetic field is a multiple of bunch spacing. Both resonances have been studied directly in dipole fields using retarding field analyzers installed in the Cornell Electron Storage Ring. These measurements are supported by both analytical models and computer simulations.
Fine structure of the pygmy dipole resonance in (136)Xe.
Savran, D; Fritzsche, M; Hasper, J; Lindenberg, K; Müller, S; Ponomarev, V Yu; Sonnabend, K; Zilges, A
2008-06-13
The photoresponse of the semimagic N=82 nucleus (136)Xe was measured up to the neutron separation energy S(n) using the (gamma, gamma') reaction. A concentration of strong dipole excitations is observed well below S(n) showing a fragmented resonancelike structure. Microscopic calculations in the quasiparticle phonon model including complex configurations of up to three phonons agree well with the experimental data in the total integrated strength, in the shape and the fragmentation of the resonance, which allows us to draw conclusions on the damping mechanism of the pygmy dipole resonance.
Absolute absorption on rubidium D1 line: including resonant dipole-dipole interactions
Weller, Lee; Siddons, Paul; Adams, Charles S; Hughes, Ifan G
2011-01-01
Here we report on measurements of the absolute absorption spectra of dense rubidium vapour on the D1 line in the weak-probe regime for temperatures up to 170 C and number densities up to 3 \\times 10^14 cm^-3. In such vapours, modifications to the homogeneous linewidth of optical transitions arise due to dipole-dipole interactions between identical atoms, in superpositions of the ground and excited states. Absolute absorption spectra were recorded with deviation of 0.1% between experiment and a theory incorporating resonant dipole-dipole interactions. The manifestation of dipole-dipole interactions is a self-broadening contribution to the homogeneous linewidth, which grows linearly with number density of atoms. Analysis of the absolute absorption spectra allow us to ascertain the value of the self-broadening coefficient for the rubidium D1 line: \\beta/2\\pi = (0.69 \\pm 0.04) \\times 10^-7 Hz cm^3, in excellent agreement with the theoretical prediction.
Electronic dipole resonance in smoky quartz
Kerssen, J.; Volger, J.
1967-01-01
Microwave absorption in smoky quartz mono-crystal is ascribed to resonance transitions of trapped electrons between initially configurational degenerated states, which are Stark-splitted by a polarizing electric field.
Resonant Dipole Nanoantenna Arrays for Enhanced Terahertz Spectroscopy
Toma, A.
2015-08-04
Our recent studies on dipole nanoantenna arrays resonating in the terahertz frequency range (0.1 – 10 THz) will be presented. The main near- and far-field properties of these nanostructures will be shown and their application in enhanced terahertz spectroscopy of tiny quantities of nanomaterials will be discussed.
Width of the chaotic layer: maxima due to marginal resonances.
Shevchenko, Ivan I
2012-06-01
Modern theoretical methods for estimating the width of the chaotic layer in the presence of prominent marginal resonances are considered in the perturbed pendulum model of nonlinear resonance. The fields of applicability of these methods are explicitly and precisely formulated. The comparative accuracy is investigated in massive and long-run numerical experiments. It is shown that the methods are naturally subdivided in classes applicable for adiabatic and nonadiabatic cases of perturbation. It is explicitly shown that the pendulum approximation of marginal resonance works well in the nonadiabatic case. In this case, the role of marginal resonances in determining the total layer width is demonstrated to diminish with increasing main parameter λ (equal to the ratio of the perturbation frequency to the frequency of small-amplitude phase oscillations on the resonance). Solely the "bending effect" is important in determining the total amplitude of the energy deviations of the near-separatrix motion at λ≳7. In the adiabatic case, it is demonstrated that the geometrical form of the separatrix cell can be described analytically quite easily by means of using a specific representation of the separatrix map. It is shown that the nonadiabatic (and, to some extent, intermediary) case is most actual, in comparison with the adiabatic one, for the physical or technical applications that concern the energy jumps in the near-separatrix chaotic motion.
C. Romig
2015-05-01
Full Text Available The technique of self absorption has been applied for the first time to study the decay pattern of low-lying dipole states of 140Ce. In particular, ground-state transition widths Γ0 and branching ratios Γ0Γ to the ground state have been investigated in the energy domain of the pygmy dipole resonance. Relative self-absorption measurements allow for a model-independent determination of Γ0. Without the need to perform a full spectroscopy of all decay channels, also the branching ratio to the ground state can be determined. The experiment on 140Ce was conducted at the bremsstrahlung facility of the superconducting Darmstadt electron linear accelerator S-DALINAC. In total, the self-absorption and, thus, Γ0 were determined for 104 excited states of 140Ce. The obtained results are presented and discussed with respect to simulations of γ cascades using the DICEBOX code.
750 GeV diphoton resonance and electric dipole moments
Choi, Kiwoon; Im, Sang Hui; Kim, Hyungjin; Mo, Doh Young
2016-09-01
We examine the implication of the recently observed 750 GeV diphoton excess for the electric dipole moments of the neutron and electron. If the excess is due to a spin zero resonance which couples to photons and gluons through the loops of massive vector-like fermions, the resulting neutron electric dipole moment can be comparable to the present experimental bound if the CP-violating angle α in the underlying new physics is of O (10-1). An electron EDM comparable to the present bound can be achieved through a mixing between the 750 GeV resonance and the Standard Model Higgs boson, if the mixing angle itself for an approximately pseudoscalar resonance, or the mixing angle times the CP-violating angle α for an approximately scalar resonance, is of O (10-3). For the case that the 750 GeV resonance corresponds to a composite pseudo-Nambu-Goldstone boson formed by a QCD-like hypercolor dynamics confining at ΛHC, the resulting neutron EDM can be estimated with α ∼(750 GeV /ΛHC) 2θHC, where θHC is the hypercolor vacuum angle.
750 GeV diphoton resonance and electric dipole moments
Kiwoon Choi
2016-09-01
Full Text Available We examine the implication of the recently observed 750 GeV diphoton excess for the electric dipole moments of the neutron and electron. If the excess is due to a spin zero resonance which couples to photons and gluons through the loops of massive vector-like fermions, the resulting neutron electric dipole moment can be comparable to the present experimental bound if the CP-violating angle α in the underlying new physics is of O(10−1. An electron EDM comparable to the present bound can be achieved through a mixing between the 750 GeV resonance and the Standard Model Higgs boson, if the mixing angle itself for an approximately pseudoscalar resonance, or the mixing angle times the CP-violating angle α for an approximately scalar resonance, is of O(10−3. For the case that the 750 GeV resonance corresponds to a composite pseudo-Nambu–Goldstone boson formed by a QCD-like hypercolor dynamics confining at ΛHC, the resulting neutron EDM can be estimated with α∼(750 GeV/ΛHC2θHC, where θHC is the hypercolor vacuum angle.
750 GeV diphoton resonance and electric dipole moments
Choi, Kiwoon; Kim, Hyungjin; Mo, Doh Young
2016-01-01
We examine the implication of the recently observed 750 GeV diphoton excess for the electric dipole moments of the neutron and electron. If the excess is due to a spin zero resonance which couples to photons and gluons through the loops of massive vector-like fermions, the resulting neutron electric dipole moment can be comparable to the present experimental bound if the CP-violating angle {\\alpha} in the underlying new physics is of O(10^{-1}). An electron EDM comparable to the present bound can be achieved through a mixing between the 750 GeV resonance and the Standard Model Higgs boson, if the mixing angle itself for an approximately pseudoscalar resonance, or the mixing angle times the CP-violating angle {\\alpha} for an approximately scalar resonance, is of O(10^{-3}). For the case that the 750 GeV resonance corresponds to a composite pseudo-Nambu-Goldstone boson formed by a QCD-like hypercolor dynamics confining at \\Lambda_HC, the resulting neutron EDM can be estimated with \\alpha ~ (750 GeV / \\Lambda_HC...
Finite amplitude method applied to giant dipole resonance in heavy rare-earth nuclei
Oishi, Tomohiro; Hinohara, Nobuo
2016-01-01
Background: The quasiparticle random phase approximation (QRPA), within the framework of the nuclear density functional theory (DFT), has been a standard tool to access the collective excitations of the atomic nuclei. Recently, finite amplitude method (FAM) has been developed, in order to perform the QRPA calculations efficiently without any truncation on the two-quasiparticle model space. Purpose: We discuss the nuclear giant dipole resonance (GDR) in heavy rare-earth isotopes, for which the conventional matrix diagonalization of the QRPA is numerically demanding. A role of the Thomas-Reiche-Kuhn (TRK) sum rule enhancement factor, connected to the isovector effective mass, is also investigated. Methods: The electric dipole photoabsorption cross section was calculated within a parallelized FAM-QRPA scheme. We employed the Skyrme energy density functional self-consistently in the DFT calculation for the ground states and FAM-QRPA calculation for the excitations. Results: The mean GDR frequency and width are mo...
Driving Rabi oscillations at the giant dipole resonance in xenon
Pabst, Stefan; Santra, Robin
2015-01-01
Free-electron lasers (FELs) produce short and very intense light pulses in the XUV and x-ray regimes. We investigate the possibility to drive Rabi oscillations in xenon with an intense FEL pulse by using the unusually large dipole strength of the giant-dipole resonance (GDR). The GDR decays within less than 30 as due to its position, which is above the $4d$ ionization threshold. We find that intensities around 10$^{18}$ W/cm$^2$ are required to induce Rabi oscillations with a period comparable to the lifetime. The pulse duration should not exceed 100 as because xenon will be fully ionized within a few lifetimes. Rabi oscillations reveal themselves also in the photoelectron spectrum in form of Autler-Townes splittings extending over several tens of electronvolt.
A Measurement of the Total Width, the Electronic Width and the Mass of the Upsilon(10580) Resonance
Aubert, Bernard; Abe, T; Abrams, G S; Adye, T; Ahmed, S; Alam, M S; Albert, J; Aleksan, Roy; Allison, J; Altenburg, D; Andreotti, M; Angelini, C; Anulli, F; Aston, D; Azzolini, V; Baak, M A; Back, J J; Bailey, S; Baldini-Ferroli, R; Band, H R; Banerjee, Sw; Barate, R; Barlow, N R; Barlow, R J; Bartoldus, R; Batignani, G; Bauer, J M; Beck, T W; Behera, P K; Bellini, F; Benayoun, M; Berger, N; Beringer, J; Bernard, D; Berryhill, J W; Best, D; Bettarini, S; Bettoni, D; Bevan, A J; Bhimji, W; Bianchi, F; Biasini, M; Blanc, F; Blaylock, G; Blinov, V E; Bloom, P; Bondioli, M; Bonneaud, G R; Borean, C; Borgland, A W; Bosisio, L; Boutigny, D; Bowerman, D A; Boyarski, A M; Boyd, J T; Bozzi, C; Brandt, T; Brau, B; Brau, J E; Breon, A B; Briand, H; Brigljevic, V; Brochard, F; Brose, J; Brown, C L; Brown, C M; Brown, D; Brown, D N; Bruinsma, M; Brunet, S; Bucci, F; Buchanan, C; Buchmüller, O L; Bugg, W; Bukin, A D; Burchat, Patricia R; Button-Shafer, J; Buzzo, A; Bóna, M; Cahn, R N; Calabrese, R; Calcaterra, A; Calderini, G; Campagnari, C; Capra, R; Carpinelli, M; Cartaro, C; Cavallo, N; Cavoto, G; Chao, M; Charles, E; Chauveau, J; Chen, E; Chen, J C; Chen, S; Cheng, C H; Chevalier, N; Christ, S; Cibinetto, G; Clark, P J; Cochran, J; Cohen-Tanugi, J; Colberg, T; Colecchia, F; Coleman, J P; Contri, R; Convery, M R; Cote-Ahern, D; Cottingham, W N; Coupal, D P; Cowan, G; Cowan, R; Crawley, H B; Cremaldi, L M; Crosetti, G; Dahmes, B; Dallapiccola, C; Danielson, N; Dasu, S; Datta, M; Dauncey, P D; David, P; Davier, M; Davis, C L; Day, C T; De Groot, N; De Nardo, Gallieno; De Sangro, R; Del Buono, L; Del Gamba, V; Del Re, D; Della Ricca, G; Di Lodovico, F; Dickopp, M; Dittongo, S; Donald, M; Dong, D; Dorfan, J; Dorigo, A; Dubitzky, R S; Dubois-Felsmann, G P; Dujmic, D; Dunwoodie, W M; Dvoretskii, A; Eckmann, R; Edwards, A J; Egede, U; Eichenbaum, A M; Eigen, G; Eisner, A M; Elmer, P; Emery, S; Ernst, J A; Eschenburg, V; Eschrich, I; Fabozzi, F; Faccini, R; Falciai, D; Farbin, A; Ferrarotto, F; Ferroni, F; Field, R C; Finocchiaro, G; Fisher, A; Flack, R L; Flächer, H U; Flood, K T; Ford, K; Ford, W T; Forti, A C; Forti, F; Fortin, D; Franek, B J; Frey, R; Fry, J R; Gabathuler, Erwin; Gabriel, T A; Gaidot, A; Gaillard, J M; Gaillard, J R; Galeazzi, F; Gallo, F; Gamba, D; Gamet, R; Gan, K K; Ganzhur, S F; Gaspero, M; Gatto, C; Geddes, N I; George, S; Gill, M S; Giorgi, M A; Giraud, P F; Gladney, L; Glanzman, T; Godang, R; Goetzen, K; Golubev, V B; Gopal, G P; Gowdy, S J; Grancagnolo, S; Graugès-Pous, E; Green, M G; Grenier, G J; Grenier, P; Gritsan, A V; Grosdidier, G; Groysman, Y; Guo, Q H; Hadavand, H K; Hadig, T; Haire, M; Halyo, V; Hamel de Monchenault, G; Hamon, O; Harrison, P F; Harrison, T J; Hart, P A; Hartfiel, B L; Harton, J L; Hast, C; Hauke, A; Hawkes, C M; Hearty, C; Held, T; Hertzbach, S S; Heusch, C A; Hicheur, A; Hill, E J; Hitlin, D G; Hodgkinson, M C; Honscheid, K; Hrynóva, T; Hu, T; Hufnagel, D; Höcker, A; Innes, W R; Ivanchenko, V N; Izen, J M; Jackson, F; Jackson, P D; Jacobsen, R G; Jawahery, A; Jayatilleke, S M; Jessop, C P; John, M J J; Johnson, J R; Judd, D; Kadel, R W; Kadyk, J; Kagan, H; Karyotakis, Yu; Kass, R; Kay, M; Kelly, M P; Kelsey, M H; Kerth, L T; Khan, A; Kim, H; Kim, P; Kirkby, D; Kitayama, I; Knowles, D J; Koch, H; Kocian, M L; Kofler, R; Kolomensky, Yu G; Koptchev, V B; Kovalskyi, D; Kowalewski, R V; Kozanecki, Witold; Kral, J F; Kravchenko, E A; Krishnamurthy, M; Kroeger, R; Kukartsev, G; Kurup, A; Kutter, P E; Kuznetsova, N; Kyberd, P; La Vaissière, C de; Lacker, H M; Lae, C K; Lafferty, G D; Lamsa, J; Lanceri, L; Lange, D J; Langenegger, U; Langer, M; Lankford, A J; Laplace, S; Latham, T E; Lavin, D; Lazzaro, A; Le Clerc, C; Le Diberder, F R; Lee, S J; Lees, J P; Legendre, M; Leith, D W G S; Lepeltier, V; Leruste, P; Levesque, J A; Levi, M E; Levy, S L; Lewandowski, B; Li, H; Lillard, V; Lista, L; Liu, R; Lo Vetere, M; LoSecco, J M; Lockman, W S; London, G W; Long, O; Lou, X C; Lu, A; Luitz, S; Luppi, E; Lusiani, A; Lutz, A M; Lynch, G; Lynch, H L; Lyon, A J; Lü, C; Lüth, V; MacFarlane, D B; MacKay, C; Macri, M; Mallik, U; Maly, E; Mancinelli, G; Mandelkern, M A; Manfredi, P F; Mangeol, D J J; Marchiori, G; Margoni, M; Marker, C E; Marsiske, H; Martínez-Vidal, F; Mattison, T S; Mayer, B; Mazur, M A; Mazzoni, M A; McKemey, A K; McKenna, J A; McMahon, T R; Meadows, B T; Messner, R; Meyer, T I; Meyer, W T; Miftakov, V; Mihályi, A; Mir, L M; Mohapatra, A K; Mommsen, R K; Monge, M R; Moore, T B; Morandin, M; Morgan, S E; Morganti, M; Morganti, S; Morii, M; Morton, G W; Muheim, F; Müller, D R; Müller-Pfefferkorn, R; Narsky, I; Nash, J A; Nauenberg, U; Neal, H; Negrini, M; Neri, N; Nicholson, H; Nogowski, R; O'Grady, C P; Ocariz, J; Oddone, P J; Ofte, I; Olaiya, E O; Olivas, A; Olsen, J; Onuchin, A P; Orimoto, T J; Otto, S; Ozcan, V E; Paar, H P; Paick, K; Palano, A; Palombo, F; Pan, Y; Panetta, J; Panvini, R S; Paoloni, E; Paolucci, P; Parry, R J; Passaggio, S; Patel, P M; Patrignani, C; Patteri, P; Payne, D J; Pelizaeus, M; Penny, R C; Perazzo, A; Perl, M; Peruzzi, I M; Peters, K; Petersen, B A; Petersen, T C; Petrak, S; Piccolo, D; Piccolo, M; Piemontese, L; Pierini, M; Pioppi, M; Piredda, G; Pivk, M; Plaszczynski, S; Playfer, S; Pompili, A; Poropat, P; Porter, F C; Posocco, M; Potter, C T; Prell, S; Prepost, R; Pripstein, M; Pulliam, T; Purohit, M V; Qi, N D; Rahatlou, S; Rama, M; Rankin, P; Ratcliff, B N; Raven, G; Re, V; Reidy, J; Ricciardi, S; Richman, J D; Ritchie, J L; Rizzo, G; Roat, C; Robbe, P; Roberts, D A; Robertson, S H; Robutti, E; Roe, N A; Romosan, A; Ronan, Michael T; Roney, J M; Rong, G; Roodman, A; Roos, L; Rosenberg, E I; Rotondo, M; Roy, J; Ryd, A; Röthel, W; Safai-Tehrani, F; Saleem, M; Salnikov, A A; Salvatore, F; Samuel, A; Sanders, D A; Sanders, P; Sandrelli, F; Santroni, A; Saremi, S; Sarti, A; Schalk, T; Schindler, R H; Schmitz, R E; Schmücker, H; Schott, G; Schubert, J; Schubert, Klaus R; Schumm, B A; Schune, M H; Schwiening, J; Schwierz, R; Schwitters, R F; Sciacca, C; Sciolla, G; Seeman, J; Seiden, A; Sekula, S J; Serednyakov, S I; Sharma, V; Shelkov, V G; Shen, B C; Shorthouse, H W; Simi, G; Simonetto, F; Sinev, N B; Skovpen, Yu I; Sloane, R J; Smith, A J S; Smith, J G; Snyder, A; Soffer, A; Soha, A; Sokoloff, M D; Solodov, E P; Spaan, B; Spanier, S M; Stark, J; Steinke, M; Stelzer, J; Stoker, D P; Stroili, R; Strom, D; Strother, P; Stugu, B; Stängle, H; Su, D; Sullivan, M K; Summers, D J; Swain, J E; T'Jampens, S; Tantot, L; Taras, P; Taylor, F; Taylor, G P; Telnov, A V; Therin, G; Thiebaux, C; Thiessen, D; Tiozzo, G; Tisserand, V; Toki, W H; Torrence, E; Tosi, S; Touramanis, C; Treadwell, E; Turri, M; Vaitsas, G; Van Hoek, W C; Varnes, H A Tanaka E W; Vasileiadis, G; Vasseur, G; Vavra, J; Verderi, M; Verkerke, W; Vidal, P B; Vitale, L; Voci, C; Voena, C; Von, J H; Vuagnin, G; Wagner, G; Wagner, S R; Wagoner, D E; Waldi, R; Walkowiak, W; Walsh, J; Wang, P; Wappler, F R; Watson, A T; Watson, N K; Weatherall, J H; Weaver, M; Weidemann, A W; Weinstein, A J R; Wenzel, W A; Wienands, U; Wilden, L; Williams, D C; Williams, J C; Willocq, S; Wilson, F F; Wilson, M G; Wilson, R J; Winter, M A; Wisniewski, W J; Won, E; Wong, Q K; Wormser, G; Wright, D H; Wright, D M; Wu Sau Lan; Wu, J; Xella, S M; Yamamoto, R K; Yang, S; Ye, S; Yi, J; Young, C C; Yu, Z; Yumiceva, F X; Yushkov, A N; Yéche, C; Zallo, A; Zghiche, A; Zhang, J; Zhang, L; Zhao, H W; Zhu, Y S; Zito, M; Çuhadar-Dönszelmann, T
2003-01-01
We present a preliminary measurement of the resonance parameters of the Upsilon(10580) resonance with the BABAR detector at the SLAC PEP-II asymmetric B factory. We measure the total decay width to be (20.7 +- 1.6 +- 2.5) MeV, the partial electronic width to be (0.321 +- 0.017 +- 0.029) kev and the mass to be (10.5793 +- 0.0004 +- 0.0012) GeV.
Pygmy and Giant Dipole Resonances by Coulomb Excitation using a Quantum Molecular Dynamics model
Tao, C; Zhang, G Q; Cao, X G; Wang, D Q Fang H W
2012-01-01
Pygmy and Giant Dipole Resonance (PDR and GDR) in Ni isotopes have been investigated by Coulomb excitation in the framework of the Isospin-dependent Quantum Molecular Dynamics model (IQMD). The spectra of $\\gamma$ rays are calculated and the peak energy, the strength and Full Width at Half Maximum (FWHM) of GDR and PDR have been extracted. Their sensitivities to nuclear equation of state, especially to its symmetry energy term are also explored. By a comparison with the other mean-field calculations, we obtain the reasonable values for symmetry energy and its slope parameter at saturation, which gives an important constrain for IQMD model. In addition, we also studied the neutron excess dependence of GDR and PDR parameters for Ni isotopes and found that the energy-weighted sum rule (EWSR) $PDR_{m_1}/GDR_{m_1}%$ increases linearly with the neutron excess.
Measurement of isospin mixing at a finite temperature in 80Zr via giant dipole resonance decay
Corsi, A.; Wieland, O.; Barlini, S.; Bracco, A.; Camera, F.; Kravchuk, V. L.; Baiocco, G.; Bardelli, L.; Benzoni, G.; Bini, M.; Blasi, N.; Brambilla, S.; Bruno, M.; Casini, G.; Ciemala, M.; Cinausero, M.; Crespi, F. C. L.; D'Agostino, M.; Degerlier, M.; Giaz, A.; Gramegna, F.; Kmiecik, M.; Leoni, S.; Maj, A.; Marchi, T.; Mazurek, K.; Meczynski, W.; Million, B.; Montanari, D.; Morelli, L.; Myalski, S.; Nannini, A.; Nicolini, R.; Pasquali, G.; Poggi, G.; Vandone, V.; Vannini, G.
2011-10-01
Isospin mixing in the hot compound nucleus 80Zr was studied by measuring and comparing the γ-ray emission from the fusion reactions 40Ca+40Ca at Ebeam=200 MeV and 37Cl+44Ca at Ebeam=153 MeV. The γ yield associated with the giant dipole resonance is found to be different in the two reactions because, in self-conjugate nuclei, the E1 selection rules forbid the decay between states with isospin I=0. The degree of mixing is deduced from statistical-model analysis of the γ-ray spectrum emitted by the compound nucleus 80Zr with the standard parameters deduced from the γ decay of the nucleus 81Rb. The results are used to deduce the zero-temperature value, which is then compared with the latest predictions. The Coulomb spreading width is found to be independent of temperature.
Experimental study of the isovector giant dipole resonance in 80Zr and 81Rb
Ceruti, S.; Camera, F.; Bracco, A.; Mentana, A.; Avigo, R.; Benzoni, G.; Blasi, N.; Bocchi, G.; Bottoni, S.; Brambilla, S.; Crespi, F. C. L.; Giaz, A.; Leoni, S.; Million, B.; Morales, A. I.; Nicolini, R.; Pellegri, L.; Riboldi, S.; Wieland, O.; Bazzacco, D.; Ciemala, M.; Farnea, E.; Gottardo, A.; Kmiecik, M.; Maj, A.; Mengoni, D.; Michelagnoli, C.; Modamio, V.; Montanari, D.; Napoli, D.; Recchia, F.; Sahin, E.; Ur, C.; Valiente-Dobón, J. J.; Wasilewska, B.; Zieblinski, M.
2017-01-01
The isovector giant dipole resonance (IVGDR) γ decay was measured in the compound nuclei 80Zr and 81Rb at an excitation energy of E*=54 MeV. The fusion reaction 40Ca+40Ca at Ebeam=136 MeV was used to form the compound nucleus 80Zr, while the reaction 37Cl+44Ca at Ebeam=95 MeV was used to form the compound nucleus 81Rb at the same excitation energy. The IVGDR parameters extracted from the analysis were compared with the ones found at higher excitation energy (E*=83 MeV). The comparison allows one to observe two different nuclear mechanisms: (i) the IVGDR intrinsic width remains constant with the excitation energy in the nucleus 81Rb; (ii) the isospin-violating spreading width (i.e., Coulomb spreading width) remains constant with the excitation energy in the nucleus 80Zr. The experimental setup used for the γ -ray detection was composed by the AGATA demonstrator array coupled to the large-volume LaBr3:Ce detectors of the HECTOR+ array.
Thermal shape fluctuation model study of the giant dipole resonance in $^{152}$Gd
Kumar, A K Rhine
2015-01-01
We have studied the giant dipole resonance (GDR) in the hot and rotating nucleus $^{152}$Gd within the framework of thermal shape fluctuation model (TSFM) built on the microscopic-macroscopic calculations of the free energies with a macroscopic approach for the GDR. Our results for GDR cross sections are in good agreement with the experimental values except for a component peaking around 17 MeV where the data has large uncertainties. Such a component is beyond our description which properly takes care of the splitting of GDR components due to the deformation and Coriolis effects. Around this 17 MeV lies the half maximum in experimental cross sections, and hence the extracted GDR widths and deformations (estimated from these widths) turn out to be overestimated and less reliable. Reproducing these widths with empirical formulae could conceal the information contained in the cross sections. Fully microscopic GDR calculations and a more careful look at the data could be useful to understand the GDR component aro...
Analytical model for double split ring resonators with arbitrary ring width
Zhurbenko, Vitaliy; Jensen, Thomas; Krozer, Viktor
2008-01-01
For the first time, the analytical model for a double split ring resonator with unequal width rings is developed. The proposed models for the resonators with equal and unequal widths are based on an impedance matrix representation and provide the prediction of performance in a wide frequency rang...
A Measurement of the Total Width, the Electronic Width, and the Mass of the Upsilon(10580) Resonance
Aubert, B; Boutigny, D; Couderc, F; Gaillard, J M; Hicheur, A; Karyotakis, Yu; Lees, J P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Le Clerc, C; Lynch, G; Merchant, A M; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, Michael T; Shelkov, V G; Telnov, A V; Wenzel, W A; Ford, K; Harrison, T J; Hawkes, C M; Morgan, S E; Watson, A T; Fritsch, M; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Steinke, M; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Wilson, F F; Çuhadar-Dönszelmann, T; Hearty, C; Mattison, T S; McKenna, J A; Thiessen, D; Kyberd, P; Teodorescu, L; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Eschrich, I; Kirkby, D; Lankford, A J; Mandelkern, M A; Mommsen, R K; Röthel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Gary, J W; Shen, B C; Wang, K; Del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Levy, S L; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Eisner, A M; Heusch, C A; Lockman, W S; Schalk, T; Schmitz, R E; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S M; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Blanc, F; Bloom, P; Chen, S; Clark, P J; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Smith, J G; Zhang, L; Chen, A; Harton, J L; Soffer, A; Toki, W H; Wilson, R J; Zeng, Q L; Altenburg, D; Brandt, T; Brose, J; Colberg, T; Dickopp, M; Feltresi, E; Hauke, A; Lacker, H M; Maly, E; Müller-Pfefferkorn, R; Nogowski, R; Otto, S; Petzold, A; Schubert, J; Schubert, Klaus R; Schwierz, R; Spaan, B; Sundermann, J E; Bernard, D; Bonneaud, G R; Brochard, F; Grenier, P; Schrenk, S; Thiebaux, C; Vasileiadis, G; Verderi, M; Bard, D J; Khan, A; Lavin, D; Muheim, F; Playfer, S; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Baldini-Ferroli, R; Calcaterra, A; De Sangro, R; Finocchiaro, G; Patteri, P; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Brandenburg, G; Morii, M; Won, E; Dubitzky, R S; Langenegger, U; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Gaillard, J R; Morton, G W; Nash, J A; Taylor, G P; Grenier, G J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Yi, J; Davier, M; Grosdidier, G; Höcker, A; Laplace, S; Le Diberder, F R; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Coleman, J P; Fry, J R; Gabathuler, Erwin; Gamet, R; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Cormack, C M; Harrison, P F; Mohanty, G B; Brown, C L; Cowan, G; Flack, R L; Flächer, H U; Green, M G; Marker, C E; McMahon, T R; Ricciardi, S; Salvatore, F; Vaitsas, G; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hart, P A; Hodgkinson, M C; Lafferty, G D; Lyon, A J; Williams, J C; Farbin, A; Hulsbergen, W D; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Flood, K T; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Stängle, H; Willocq, S; Cowan, R; Sciolla, G; Taylor, F; Yamamoto, R K; Mangeol, D J J; Patel, P M; Robertson, S H; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L M; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Taras, P; Nicholson, H; Cavallo, N; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M; Bulten, H; Raven, G; Wilden, L; Jessop, C P; LoSecco, J M; Gabriel, T A; Allmendinger, T; Brau, B; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Rahimi, A M; Ter-Antonian, R; Wong, Q K; Brau, J E; Frey, R; Igonkina, O; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Tiozzo, G; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; La Vaissière, C de; Del Buono, L; Hamon, O; John, M J J; Leruste, P; Ocariz, J; Pivk, M; Roos, L; T'Jampens, S; Therin, G; Manfredi, P F; Re, V; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Anulli, F; Biasini, M; Peruzzi, I M; Pioppi, M; Angelini, C; Batignani, G; Bettarini, S; Bondioli, M; Bucci, F; Calderini, G; Carpinelli, M; Del Gamba, V; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Martínez-Vidal, F; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Sandrelli, F; Walsh, J; Haire, M; Judd, D; Paick, K; Wagoner, D E; Danielson, N; Elmer, P; Lü, C; Miftakov, V; Olsen, J; Smith, A J S; Bellini, F; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Li Gioi, L; Mazzoni, M A; Morganti, S; Pierini, M; Piredda, G; Safai-Tehrani, F; Voena, C; Christ, S; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B J; Geddes, N I; Gopal, G P; Olaiya, E O; Aleksan, Roy; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P F; Hamel de Monchenault, G; Kozanecki, Witold; Langer, M; Legendre, M; London, G W; Mayer, B; Schott, G; Vasseur, G; Yéche, C; Zito, M; Purohit, M V; Weidemann, A W; Yumiceva, F X; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmüller, O L; Convery, M R; Cristinziani, M; De Nardo, Gallieno; Donald, M; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W M; Elsen, E E; Fan, S; Field, R C; Fisher, A; Glanzman, T; Gowdy, S J; Hadig, T; Halyo, V; Hast, C; Hrynóva, T; Innes, W R; Kelsey, M H; Kim, P; Kocian, M L; Leith, D W G S; Libby, J; Luitz, S; Lüth, V; Lynch, H L; Marsiske, H; Messner, R; Müller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Petrak, S; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Seeman, J; Simi, G; Snyder, A; Soha, A; Stelzer, J; Su, D; Sullivan, M K; Vavra, J; Wagner, S R; Weaver, M; Weinstein, A J R; Wienands, U; Wisniewski, W J; Wittgen, M; Wright, D H; Yarritu, A K; Young, C C; Burchat, Patricia R; Edwards, A J; Meyer, T I; Petersen, B A; Roat, C; Ahmed, S; Alam, M S; Ernst, J A; Saeed, M A; Saleem, M; Wappler, F R; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Kim, H; Ritchie, J L; Satpathy, A; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bóna, M; Gallo, F; Gamba, D; Borean, C; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Poropat, P; Vitale, L; Vuagnin, G; Panvini, R S; Banerjee, Sw; Brown, C M; Fortin, D; Jackson, P D; Kowalewski, R V; Roney, J M; Band, H R; Dasu, S; Datta, M; Eichenbaum, A M; Hollar, J J; Johnson, J R; Kutter, P E; Li, H; Liu, R; Di Lodovico, F; Mihályi, A; Mohapatra, A K; Pan, Y; Prepost, R; Sekula, S J; Tan, P; Von Wimmersperg-Töller, J H; Wu, J; Wu, S L; Yu, Z; Neal, H
2004-01-01
We present a measurement of the parameters of the $\\Upsilon(10580)$ resonance based on a dataset collected with the BABAR detector at the SLAC PEP-II asymmetric $B$ factory. We measure the total width $\\Gamma_{\\rm tot}$ to be $(20.7\\pm1.6\\pm2.5) {\\rm MeV}$, the electronic partial width $\\Gamma_{ee} = (0.321\\pm0.017\\pm0.029) {\\rm keV}$ and the mass $M = (10579.3\\pm0.4\\pm1.2) {\\rm MeV/c^2}$.
Cooper, C. M.; Weisberg, D. B.; Khalzov, I.; Milhone, J.; Flanagan, K.; Peterson, E.; Wahl, C.; Forest, C. B.
2016-10-01
The loss width of plasma in the WiPAL multi-dipole magnetic ring cusp [Cooper et al., Phys. Plasmas 21, 13505 (2014); Forest et al., J. Plasma Phys. 81, 345810501 (2015)] has been directly measured using a novel array of probes embedded in the insulating plasma limiters. The large plasma volume ( ˜10 m3), small loss area associated with strong rare earth permanent magnets ( Bo˜2.23 kG at face), and large heating power ( ≤200 kW) produces a broad range of electron temperatures ( 2 magnetic fields, differs from previous devices: the cusp loss width is much larger than the Debye length and electron gyroradius and comparable to the collision length. Plasma parameters measured at the surface of ceramic limiter tiles covering the magnets and along radial chords in the cusp magnetic field indicate that electron density and temperature are nearly constant on magnetic field lines and that the mirror forces play little role in confining the plasma other than to constrict the loss area. Particle balance modeling is used to determine the cross field diffusion coefficient base on the measured losses to the limiters. The experimentally determined cross field diffusion coefficient (which determines the cusp loss width) is consistent with ambipolar diffusion across five orders of magnitude. The ambipolar diffusion across a given field line is set primarily by the electron-neutral collisions in the region where the magnetic field is the weakest, even though these plasmas can have ionization fractions near 1.
Loading Dynamics and Characteristics of a Far Off-Resonance Optical Dipole Trap
Mickelson, P. G.; Martinez, Y. N.; Nagel, S. B.; Traverso, A. J.; Killian, T. C.
2007-10-01
We implement an optical dipole trap in a crossed beam configuration for experiments with ultracold strontium. Strontium atoms cooled to nearly 1 μK are loaded into the optical dipole trap from a magneto-optical trap operating on the 689 nm intercombination line. Loading dynamics and characteristics of the far off-resonance dipole trap are explored as part of our group's study of ultracold collisions in strontium.
Nature of the pygmy dipole resonance in Ce-140 studied in (alpha, alpha 'gamma) experiments
Savran, D.; Babilon, M.; van den Berg, A. M.; Harakeh, M. N.; Hasper, J.; Matic, A.; Wortche, H. J.; Zilges, A.
2006-01-01
A concentration of electric-dipole excitations below the particle threshold, which is frequently denoted as the pygmy dipole resonance, has been studied in the semimagic nucleus Ce-140 in (alpha, alpha(')gamma) experiments at E-alpha=136 MeV. The technique of alpha-gamma coincidence experiments allo
Investigation of the Pygmy Dipole Resonance in (alpha, alpha 'gamma) coincidence experiments
Savran, D.; Babilon, M.; van den Berg, A. M.; Harakeh, M. N.; Hasper, J.; Wortche, H. J.; Zilges, A.
2007-01-01
We report on first results from experiments using the (alpha, alpha'gamma) reaction at E alpha = 136 MeV to investigate bound electric dipole (El) excitations building the so-called Pygmy Dipole Resonance (PDR) in the semi-magic nucleus Ce-140. The method of (alpha, alpha'gamma) allows the separatio
Calculating Resonance Positions and Widths Using the Siegert Approximation Method
Rapedius, Kevin
2011-01-01
Here, we present complex resonance states (or Siegert states) that describe the tunnelling decay of a trapped quantum particle from an intuitive point of view that naturally leads to the easily applicable Siegert approximation method. This can be used for analytical and numerical calculations of complex resonances of both the linear and nonlinear…
Wieland, O.; Bracco, A.; Camera, F.; Benzoni, G.; Blasi, N.; Brambilla, S.; Crespi, F.; Giussani, A.; Leoni, S.; Mason, P.; Million, B.; Moroni, A.; Barlini, S.; Kravchuk, V. L.; Gramegna, F.; Lanchais, A.; Mastinu, P.; Maj, A.; Brekiesz, M.; Kmiecik, M.; Bruno, M.; Geraci, E.; Vannini, G.; Casini, G.; Chiari, M.; Nannini, A.; Ordine, A.; Ormand, E.
2006-07-01
The γ decay of the giant dipole resonance (GDR) in the Ce132 compound nucleus with temperature up to ≈4MeV has been measured, using the reaction Ni64+Zn68 at Ebeam=300, 400, and 500 MeV. The γ and charged particles measured in coincidence with recoils are consistent with a fully equilibrated compound nucleus emission. The GDR width, obtained with the statistical model analysis, is found to increase almost linearly with temperature. This increase is rather well reproduced within a model including thermal shape fluctuations and the lifetime of the compound nucleus.
Shell Model Study on the Proton Pigmy Dipole Resonances in ~(17, 18)Ne
无
2011-01-01
The proton pygmy dipole resonances (PDRs) in proton rich nuclei 17, 18Ne have been investigated in the framework of interacting shell model. The shell model with the self-consistent Skyrme-Hartree-Fock wave functions has well reproduced
On the collectivity of Pygmy Dipole Resonance within schematic TDA and RPA models
Baran, V; Colonna, M; Di Toro, M; Croitoru, A; Nicolin, A I
2014-01-01
Within schematic models based on the Tamm-Dancoff Approximation and the Random-Phase Approximation with separable interactions, we investigate the physical conditions which determine the emergence of the Pygmy Dipole Resonance in the E1 response of atomic nuclei. We find that if some particle-hole excitation manifests a different, weaker residual interaction, an additional mode will appear, with an energy centroid closer to the distance between two major shells and therefore well below the Giant Dipole Resonance. This state, together with Giant Dipole Resonance, exhausts all the transition strength in the Tamm-Dancoff Approximation and all the Energy Weighted Sum Rule in the Random-Phase Approximation. These features suggest a collective nature for this mode which we identify with the Pygmy Dipole Resonance.
Enhanced second-harmonic generation driven from magnetic dipole resonance in AlGaAs nanoantennas
Carletti, Luca; Rocco, Davide; Locatelli, Andrea; Gili, Valerio; Leo, Giuseppe; De Angelis, Costantino
2016-04-01
We model the linear and nonlinear optical response of disk-shaped AlGaAs nanoantennas. We design nanoantennas with a magnetic dipole resonant mode in the near-infrared wavelength range, and we analyze volume second-harmonic generation driven by a magnetic dipole resonance by predicting a conversion efficiency exceeding 10-3 with 1 GW/cm2 of pump intensity.
Calculating resonance positions and widths using the Siegert approximation method
Rapedius, Kevin
2011-01-01
Here we present complex resonance states (or Siegert states), that describe the tunneling decay of a trapped quantum particle, from an intuitive point of view which naturally leads to the easily applicable Siegert approximation method that can be used for analytical and numerical calculations of complex resonances of both the linear and nonlinear Schr\\"odinger equation. Our approach thus complements other treatments of the subject that mostly focus on methods based on continuation in the complex plane or on semiclassical approximations.
Demonstration of Magnetic Dipole Resonances of Dielectric Nanospheres in the Visible Region
Evlyukhin, A. B.; Novikov, S. M.; Zywietz, U.
2012-01-01
dipole excitation. Due to high permittivity, the magnetic dipole resonance is observed in the visible spectral range for Si nanoparticles with diameters of similar to 200 nm, thereby opening a way to the realization of isotropic optical metamaterials with strong magnetic responses in the visible region.......Strong resonant light scattering by individual spherical Si nanoparticles is experimentally demonstrated, revealing pronounced resonances associated with the excitation of magnetic and electric modes in these nanoparticles. It is shown that the low-frequency resonance corresponds to the magnetic...
Resonance width distribution in RMT: Weak-coupling regime beyond Porter-Thomas
Fyodorov, Yan V.; Savin, Dmitry V.
2015-05-01
We employ the random matrix theory (RMT) framework to revisit the distribution of resonance widths in quantum chaotic systems weakly coupled to the continuum via a finite number M of open channels. In contrast to the standard first-order perturbation theory treatment we do not a priori assume the resonance widths being small compared to the mean level spacing. We show that to the leading order in weak coupling the perturbative χ^2M distribution of the resonance widths (in particular, the Porter-Thomas distribution at M = 1) should be corrected by a factor related to a certain average of the ratio of square roots of the characteristic polynomial (“spectral determinant”) of the underlying RMT Hamiltonian. A simple single-channel expression is obtained that properly approximates the width distribution also at large resonance overlap, where the Porter-Thomas result is no longer applicable.
Resonance widths in open microwave cavities studied by harmonic inversion.
Kuhl, U; Höhmann, R; Main, J; Stöckmann, H-J
2008-06-27
From the measurement of a reflection spectrum of an open microwave cavity, the poles of the scattering matrix in the complex plane have been determined. The resonances have been extracted by means of the harmonic inversion method. By this, it became possible to resolve the resonances in a regime where the linewidths exceed the mean level spacing up to a factor of 10, a value inaccessible in experiments up to now. The obtained experimental distributions of linewidths were found to be in perfect agreement with predictions from random matrix theory when wall absorption and fluctuations caused by couplings to additional channels are considered.
Determination of level widths in 15N using nuclear resonance fluorescence
Szücs T.
2015-01-01
Full Text Available Level widths in 15N have been measured with the nuclear resonance fluorescence (NRF technique. Solid nitrogen compounds, bremsstrahlung, and HPGe detectors have been used as target, beam, and detectors, respectively. The preliminarily level widths are in agreement with the literature values, but more precise.
Ciemała, M.; Kmiecik, M.; Maj, A.; Mazurek, K.; Bracco, A.; Kravchuk, V. L.; Casini, G.; Barlini, S.; Baiocco, G.; Bardelli, L.; Bednarczyk, P.; Benzoni, G.; Bini, M.; Blasi, N.; Brambilla, S.; Bruno, M.; Camera, F.; Carboni, S.; Cinausero, M.; Chbihi, A.; Chiari, M.; Corsi, A.; Crespi, F. C. L.; D'Agostino, M.; Degerlier, M.; Fornal, B.; Giaz, A.; Gramegna, F.; Krzysiek, M.; Leoni, S.; Marchi, T.; Matejska-Minda, M.; Mazumdar, I.; Meczyński, W.; Million, B.; Montanari, D.; Morelli, L.; Myalski, S.; Nannini, A.; Nicolini, R.; Pasquali, G.; Piantelli, S.; Prete, G.; Roberts, O. J.; Schmitt, Ch.; Styczeń, J.; Szpak, B.; Valdré, S.; Wasilewska, B.; Wieland, O.; Wieleczko, J. P.; Ziebliński, M.; Dudek, J.; Dinh Dang, N.
2015-05-01
High-energy giant dipole resonance (GDR) γ rays were measured following the decay of the hot, rotating compound nucleus of 88Mo, produced at excitation energies of 124 and 261 MeV. The reaction 48Ti + 40Ca at 300 and 600 MeV bombarding energies has been used. The data were analyzed using the statistical model Monte Carlo code gemini++. It allowed extracting the giant dipole resonance parameters by fitting the high-energy γ -ray spectra. The extracted GDR widths were compared with the available data at lower excitation energy and with theoretical predictions based on (i) The Lublin-Strasbourg drop macroscopic model, supplemented with thermal shape fluctuations analysis, and (ii) The phonon damping model. The theoretical predictions were convoluted with the population matrices of evaporated nuclei from the statistical model gemini++. Also a comparison with the results of a phenomenological expression based on the existing systematics, mainly for lower temperature data, is presented and discussed. A possible onset of a saturation of the GDR width was observed around T =3 MeV.
Finite amplitude method applied to the giant dipole resonance in heavy rare-earth nuclei
Oishi, Tomohiro; Kortelainen, Markus; Hinohara, Nobuo
2016-03-01
Background: The quasiparticle random phase approximation (QRPA), within the framework of nuclear density functional theory (DFT), has been a standard tool to access the collective excitations of atomic nuclei. Recently, the finite amplitude method (FAM) was developed in order to perform the QRPA calculations efficiently without any truncation on the two-quasiparticle model space. Purpose: We discuss the nuclear giant dipole resonance (GDR) in heavy rare-earth isotopes, for which the conventional matrix diagonalization of the QRPA is numerically demanding. A role of the Thomas-Reiche-Kuhn (TRK) sum rule enhancement factor, connected to the isovector effective mass, is also investigated. Methods: The electric dipole photoabsorption cross section was calculated within a parallelized FAM-QRPA scheme. We employed the Skyrme energy density functional self-consistently in the DFT calculation for the ground states and FAM-QRPA calculation for the excitations. Results: The mean GDR frequency and width are mostly reproduced with the FAM-QRPA, when compared to experimental data, although some deficiency is observed with isotopes heavier than erbium. A role of the TRK enhancement factor in actual GDR strength is clearly shown: its increment leads to a shift of the GDR strength to higher-energy region, without a significant change in the transition amplitudes. Conclusions: The newly developed FAM-QRPA scheme shows remarkable efficiency, which enables one to perform systematic analysis of GDR for heavy rare-earth nuclei. The theoretical deficiency of the photoabsorption cross section could not be improved by only adjusting the TRK enhancement factor, suggesting the necessity of an approach beyond self-consistent QRPA and/or a more systematic optimization of the energy density functional (EDF) parameters.
PCB Slot Based Transformers to Avoid Common-Mode Resonances in Connected Arrays of Dipoles
Cavallo, D.; Neto, A.; Gerini, G.
2010-01-01
The scanning performances of connected arrays are degraded by the excitation of common-mode resonances that are compatible with balanced feeding lines. Here, a strategy to avoid these resonances is outlined. The strategy involves feeding the dipoles via printed circuit board (PCB) based transformers
Structure and decay properties of spin-dipole giant resonances within a semimicroscopical approach
Moukhai, EA; Rodin, VA; Urin, MH
1999-01-01
A semimicroscopical approach is applied to calculate: (i) strength functions for the charge-exchange spin-dipole giant resonances in the Pb-208 parent nucleus; (ii) partial and total branching ratios for the direct proton decay of the resonance in Bi-208. The approach is based on continuum-RPA calcu
Excitation of pygmy dipole resonance in neutron-rich nuclei via Coulomb and nuclear fields
A Vitturi; E G Lanza; M V Andrés; F Catara; D Gambacurta
2010-07-01
We study the nature of the low-lying dipole strength in neutron-rich nuclei, often associated with the pygmy dipole resonance. The states are described within the Hartree–Fock plus RPA formalism, using different parametrizations of the Skyrme inter-action. We show how the information from combined reaction processes involving the Coulomb and different mixtures of isoscalar and isovector nuclear interactions can provide a clue to reveal the characteristic features of these states.
Coupled-Channel Models of Direct-Semidirect Capture via Giant-Dipole Resonances
Thompson, I J [Lawrence Livermore National Laboratory (LLNL); Escher, Jutta E [ORNL; Arbanas, Goran [ORNL
2013-01-01
Semidirect capture, a two-step process that excites a giant-dipole resonance followed by its radiative de-excitation, is a dominant process near giant-dipole resonances, that is, for incoming neutron energies within 5 20 MeV. At lower energies such processes may affect neutron capture rates that are relevant to astrophysical nucleosynthesis models. We implement a semidirect capture model in the coupled-channel reaction code Fresco and validate it by comparing the cross section for direct-semidirect capture 208Pb(n,g)209Pb to experimental data. We also investigate the effect of low-energy electric dipole strength in the pygmy resonance. We use a conventional single-particle direct-semidirect capture code Cupido for comparison. Furthermore, we present and discuss our results for direct-semidirect capture reaction 130Sn(n,g)131Sn, the cross section of which is known to have a significant effect on nucleosynthesis models.
Polarization-rotation resonances with subnatural widths using a control laser
Chanu, Sapam Ranjita; Bharti, Vineet; Wasan, Ajay; Natarajan, Vasant
2013-01-01
We demonstrate extremely narrow resonances for polarization rotation in an atomic vapor. The resonances are created using a strong control laser on the same transition, which polarizes the atoms due to optical pumping among the magnetic sublevels. As the power in the control laser is increased, successively higher-order nested polarization rotation resonances are created, with progressively narrower linewidths. We study these resonances in the $D_2$ line of Rb in a room-temperature vapor cell, and demonstrate a width of $0.14 \\, \\Gamma$ for the third-order rotation. The explanation based on a simplified $\\Lambda$V-type level structure is borne out by a density-matrix analysis of the system. The dispersive lineshape and subnatural width of the resonance lends itself naturally to applications such as laser locking to atomic transitions and precision measurements.
Studies of Beam Induced Electron Cloud Resonances in Dipole Magnetic Fields
Calvey, J R; Makita, J; Venturini, M
2016-01-01
The buildup of low energy electrons in an accelerator, known as electron cloud, can be severely detrimental to machine performance. Under certain beam conditions, the beam can become resonant with the cloud dynamics, accelerating the buildup of electrons. This paper will examine two such effects: multipacting resonances, in which the cloud development time is resonant with the bunch spacing, and cyclotron resonances, in which the cyclotron period of electrons in a magnetic field is a multiple of bunch spacing. Both resonances have been studied directly in dipole fields using retarding field analyzers installed in the Cornell Electron Storage Ring (CESR). These measurements are supported by both analytical models and computer simulations.
Chatzakis, Ioannis; Luo, Liang; Wang, Jigang; Shen, Nian Hai; Koschny, Thomas; Soukoulis, Costas
2011-03-01
Currently, there is strong interest to explore the dynamic control of the electromagnetic properties of metamaterials, which have important implications on their optoelectronic applications. While the design, fabrication and photo-doping of metamaterial/semiconductor structures have been actively pursued, some fundamental issues related to highly photo-excited states, their dynamic tuning and temporal evolution remain open. Using optical-pump terahertz probe spectroscopy, we report on the pump fluence dependence of the electric dipole resonance tunability in metamaterials. We find a previously undiscovered large non-monotonic variation on the strength of the dipole resonance peak with the photo-injected carrier concentration.
Tunable Dipole Surface Plasmon Resonances of Silver Nanoparticles by Cladding Dielectric Layers.
Liu, Xiaotong; Li, Dabing; Sun, Xiaojuan; Li, Zhiming; Song, Hang; Jiang, Hong; Chen, Yiren
2015-07-28
The tunability of surface plasmon resonance can enable the highest degree of localised surface plasmon enhancement to be achieved, based on the emitting or absorbing wavelength. In this article, tunable dipole surface plasmon resonances of Ag nanoparticles (NPs) are realized by modification of the SiO2 dielectric layer thicknesses. SiO2 layers both beneath and over the Ag NPs affected the resonance wavelengths of local surface plasmons (LSPs). By adjusting the SiO2 thickness beneath the Ag NPs from 5 nm to 20 nm, the dipole surface plasmon resonances shifted from 470 nm to 410 nm. Meanwhile, after sandwiching the Ag NPs by growing SiO2 before NPs fabrication and then overcoating the NPs with various SiO2 thicknesses from 5 nm to 20 nm, the dipole surface plasmon resonances changed from 450 nm to 490 nm. The SiO2 cladding dielectric layer can tune the Ag NP surface charge, leading to a change in the effective permittivity of the surrounding medium, and thus to a blueshift or redshift of the resonance wavelength. Also, the quadrupole plasmon resonances were suppressed by the SiO2 cladding layer because the dielectric SiO2 can suppress level splitting of surface plasmon resonances caused by the Ag NP coupling effect.
Sub-wavelength metamaterial cylinders with multiple dipole resonances
Arslanagic, Samel; Breinbjerg, Olav
2009-01-01
It has been shown that the sub-wavelength resonances of the individual MTM cylinders also occur for electrically small configurations combining 2 or 4 cylinders. For the 2-and 4-cylinder configurations the overall size is 1/20 and 1/12.5 of the smallest wavelength, respectively. These MTM...... configuration thus offer the possibility for multi-resonant electrically small configurations....
Far-field Fano resonance in nanoring lattices modeled from extracted, point dipole polarizability
DeJarnette, Drew; Forcherio, Gregory T. [Microelectronics and Photonics Graduate Program, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Blake, Phillip [Department of Chemical Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Keith Roper, D., E-mail: dkroper@uark.edu [Microelectronics and Photonics Graduate Program, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Department of Chemical Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States)
2014-01-14
Coupling and extinction of light among particles representable as point dipoles can be characterized using the coupled dipole approximation (CDA). The analytic form for dipole polarizability of spheroidal particles supports rapid electrodynamic analysis of nanoparticle lattices using CDA. However, computational expense increases for complex shapes with non-analytical polarizabilities which require discrete dipole (DDA) or higher order approximations. This work shows fast CDA analysis of assembled nanorings is possible using a single dipole nanoring polarizability extrapolated from a DDA calculation by summing contributions from individual polarizable volume elements. Plasmon resonance wavelengths of nanorings obtained using extracted polarizabilities blueshift as wall dimensions-to-inner radius aspect ratio increases, consistent with published theory and experiment. Calculated far-field Fano resonance energy maximum and minimum wavelengths were within 1% of full volume element results. Considering polarizability allows a more complete physical picture of predicting plasmon resonance location than metal dielectric alone. This method reduces time required for calculation of diffractive coupling more than 40 000-fold in ordered nanoring systems for 400–1400 nm incident wavelengths. Extension of this technique beyond nanorings is possible for more complex shapes that exhibit dipolar or quadrupole radiation patterns.
First principles description of the giant dipole resonance in 16O
Bacca, Sonia; Hagen, Gaute; Orlandini, Giuseppina; Papenbrock, Thomas
2013-01-01
We present an ab-initio calculation of the giant dipole resonance in 16O based on a nucleon-nucleon (NN) interaction from chiral effective field theory that reproduces NN scattering data with high accuracy. By merging the Lorentz integral transform and the coupled-cluster methods, we extend the previous theoretical limits for break-up observables in light nuclei with mass numbers (A<=7), and address the collective giant dipole resonance of 16O. We successfully benchmark the new approach against virtually exact results from the hyper-spherical harmonics method in 4He. Our results for 16O reproduce the position and the total strength (bremsstrahlung sum rule) of the dipole response very well. When compared to the cross section from photo-absorption experiments the theoretical curve exhibits a smeared form of the peak. The tail region between 40 and 100 MeV is reproduced within uncertainties.
郭远清; 黄光明; 林洁丽; 段传喜; 李奉延; 李津蕊; 刘煜炎
2001-01-01
An intracavity CO laser magnetic resonance spectrometer with homogeneous dc electric field applied via a pairof parallel Stark plates in the absorption cell is used to measure the electric dipole moments of free radicals.Taking advantage of the high sensitivity and high resolution of this technique and the Stark effect, highlyresolved saturated absorption spectra of the ν ＝ 1 - 0 transition of 15 N16 O in the ground state X2 П3/2 have beensuccessfully observed in the presence of a low electric field. The electric dipole moment of NO in the electronicground state is determined asμ ＝ 0.1566 ± 14D (Debye) from the analysis of the observed spectra, confirmingthat, combined with the Stark field, the laser magnetic resonance technique can be an effective and reliableapproach for the precise measurement of electric dipole moments of free radicals, especially unstable ones.
Origins of dipole resonance strength fragmentation in calcium and titanium isotopes
Skorodumina Iu. A.
2012-12-01
Full Text Available Theoretical description of dipole resonances in 46Ti, 48Ti, 50Ti, 48Ca, 40Ca was performed. The distribution of the “hole” among the states of final nuclei was taken into account using information on pick-up reactions. The obtained results are in reasonable agreement with experimental data.
Proton decay from the isoscalar giant dipole resonance in Ni-58
Hunyadi, M.; Hashimoto, H.; Li, T.; Akimune, H.; Fujimura, H.; Fujiwara, M.; Gacsi, Z.; Garg, U.; Hara, K.; Harakeh, M. N.; Hoffman, J.; Itoh, M.; Murakami, T.; Nakanishi, K.; Nayak, B. K.; Okumura, S.; Sakaguchi, H.; Terashima, S.; Uchida, M.; Yasuda, Y.; Yosoi, M.
2009-01-01
Proton decay from the 3 (h) over bar omega isoscalar giant dipole resonance (ISGDR) in Ni-58 has been measured using the (alpha, alpha' p) reaction at a bombarding energy of 386 MeV to investigate its decay properties. We have extracted the ISGDR strength under the coincidence condition between inel
Proton decay from the isoscalar giant dipole resonance in 58Ni
Hunyadi, M.; Hashimoto, H.; Li, T.; Akimune, H.; Fujimura, H.; Fujiwara, M.; Gacsi, Z.; Garg, U.; Hara, K.; Harakeh, M. N.; Hoffman, J.; Itoh, M.; Murakami, T.; Nakanishi, K.; Nayak, B. K.; Okumura, S.; Sakaguchi, H.; Terashima, S.; Uchida, M.; Yasuda, Y.; Yosoi, M.
2009-01-01
Proton decay from the 3 (h) over bar omega isoscalar giant dipole resonance (ISGDR) in Ni-58 has been measured using the (alpha, alpha' p) reaction at a bombarding energy of 386 MeV to investigate its decay properties. We have extracted the ISGDR strength under the coincidence condition between inel
Neutron-skin thickness from the study of the anti-analog giant dipole resonance
Krasznahorkay, A.; Stuhl, L.; Csatlós, M.; Algora, A.; Gulyás, J.; Timár, J.; Paar, N.; Vretenar, D.; Boretzky, K.; Heil, M.; Litvinov, Yu A.; Rossi, D.; Scheidenberger, C.; Simon, H.; Weick, H.; Bracco, A.; Brambilla, S.; Blasi, N.; Camera, F.; Giaz, A.; Million, B.; Pellegri, L.; Riboldi, S.; Wieland, O.; Altstadt, S.; Fonseca, M.; Glorius, J.; Göbel, K.; Heftrich, T.; Koloczek, A.; Kräckmann, S.; Langer, C.; Plag, R.; Pohl, M.; Rastrepina, G.; Reifarth, R.; Schmidt, S.; Sonnabend, K.; Weigand, M.; Harakeh, M. N.; Kalantar-Nayestanaki, N.; Rigollet, C.; Bagchi, S.; Najafi, M. A.; Aumann, T.; Atar, L.; Heine, M.; Holl, M.; Movsesyan, A.; Schrock, P.; Volkov, V.; Wamers, F.; Fiori, E.; Löher, B.; Marganiec, J.; Savran, D.; Johansson, H. T.; Fernández, P. Diaz; Garg, U.; Balabanski, D. L.
2012-01-01
The gamma-decay of the anti-analog of the giant dipole resonance (AGDR) has been measured to the isobaric analog state excited in the p(124Sn,n) reaction at a beam energy of 600 MeV/nucleon. The energy of the transition was also calculated with state-of-the-art self-consistent random-phase approxima
Rusev, G.Y.
2006-07-01
Investigations of the dipole-strength distributions in {sup 92}Mo, {sup 98}Mo and {sup 100}Mo were carried out by means of the method of nuclear resonance fluorescence. The low-lying excitations in the nuclides {sup 92}Mo, {sup 98}Mo and {sup 100}Mo have been studied in photon-scattering experiments at an electron energy of 6 MeV at the ELBE accelerator and at electron energies from 3.2 to 3.8 MeV at the Dynamitron accelerator. Five levels were observed in {sup 92}Mo. Five levels in {sup 98}Mo and 14 in {sup 100}Mo were identified for the first time in the energy range from 2 to 4 MeV. Dipole-strength distributions up to the neutron-separation energies in the nuclides {sup 92}Mo, {sup 98}Mo and {sup 100}Mo have been investigated at the ELBE accelerator. Because of the possible observation of transitions in the neighboring nuclei produced via ({gamma},n) reaction, additional measurements at electron energies of 8.4 and 7.8 MeV, below the neutron-separation energy, were performed on {sup 98}Mo and {sup 100}Mo, respectively. The number of transitions assigned to {sup 92}Mo, {sup 98}Mo and {sup 100}Mo is 340, 485 and 499, respectively, the main part of them being dipole transitions. Statistical properties of the observed transitions are obtained. The continuum contains the ground-state transitions as well as the branching transitions to the low-lying levels and the subsequent deexcitations of these levels. (orig.)
Dinh Dang, N.; Ciemala, M.; Kmiecik, M.; Maj, A.
2013-05-01
The line shapes of giant dipole resonance (GDR) in the decay of the compound nucleus 88Mo, which is formed after the fusion-evaporation reaction 48Ti + 40Ca at various excitation energies E* from 58 to 308 MeV, are generated by averaging the GDR strength functions predicted within the phonon damping model (PDM) using the empirical probabilities for temperature and angular momentum. The average strength functions are compared with the PDM strength functions calculated at the mean temperature and mean angular momentum, which are obtained by averaging the values of temperature and angular momentum using the same temperature and angular momentum probability distributions, respectively. It is seen that these two ways of generating the GDR linear line shape yield very similar results. It is also shown that the GDR width approaches a saturation at angular momentum J≥ 50 ℏ at T=4 MeV and at J≥ 70 ℏ at any T.
Dang, N Dinh; Kmiecik, M; Maj, A
2013-01-01
The line shapes of giant dipole resonance (GDR) in the decay of the compound nucleus $^{88}$Mo, which is formed after the fusion-evaporation reaction $^{48}$Ti + $^{40}$Ca at various excitation energies $E^{*}$ from 58 to 308 MeV, are generated by averaging the GDR strength functions predicted within the phonon damping model (PDM) using the empirical probabilities for temperature and angular momentum. The average strength functions are compared with the PDM strength functions calculated at the mean temperature and mean angular momentum, which are obtained by averaging the values of temperature and angular momentum using the same temperature and angular-momentum probability distributions, respectively. It is seen that these two ways of generating the GDR linear line shape yield very similar results. It is also shown that the GDR width approaches a saturation at angular momentum $J\\geq$ 50$\\hbar$ at $T=$ 4 MeV and at $J\\geq$ 70$\\hbar$ at any $T$.
Evolution of the pygmy dipole resonance in Sn isotopes
Toft, H. K.; Larsen, A. C.; Bürger, A.; Guttormsen, M.; Görgen, A.; Nyhus, H. T.; Renstrøm, T.; Siem, S.; Tveten, G. M.; Voinov, A.
2011-04-01
Nuclear level density and γ-ray strength functions of Sn121,122 below the neutron separation energy are extracted with the Oslo method using the (He3,He3'γ) and (He3,αγ) reactions. The level densities of Sn121,122 display steplike structures, interpreted as signatures of neutron pair breaking. An enhancement in both strength functions, compared to standard models for radiative strength, is observed in our measurements for Eγ≳5.2 MeV. This enhancement is compatible with pygmy resonances centered at ≈8.4(1) and ≈8.6(2) MeV, respectively, and with integrated strengths corresponding to ≈1.8-5+1% of the classical Thomas-Reiche-Kuhn sum rule. Similar resonances were also seen in Sn116-119. Experimental neutron-capture cross reactions are well reproduced by our pygmy resonance predictions, while standard strength models are less successful. The evolution as a function of neutron number of the pygmy resonance in Sn116-122 is described as a clear increase of centroid energy from 8.0(1) to 8.6(2) MeV, but with no observable difference in integrated strengths.
Optical Control of the Resonant Dipole-Dipole Interaction between Rydberg Atoms
de Léséleuc, Sylvain; Barredo, Daniel; Lienhard, Vincent; Browaeys, Antoine; Lahaye, Thierry
2017-08-01
We report on the local control of the transition frequency of a spin 1 /2 encoded in two Rydberg levels of an individual atom by applying a state-selective light shift using an addressing beam. With this tool, we first study the spectrum of an elementary system of two spins, tuning it from a nonresonant to a resonant regime, where "bright" (super-radiant) and "dark" (subradiant) states emerge. We observe the collective enhancement of the microwave coupling to the bright state. We then show that after preparing an initial single spin excitation and letting it hop due to the spin-exchange interaction, we can freeze the dynamics at will with the addressing laser, while preserving the coherence of the system. In the context of quantum simulation, this scheme opens exciting prospects for engineering inhomogeneous X Y spin Hamiltonians or preparing spin-imbalanced initial states.
Purcell effect of asymmetric dipole source distributions in nanowire resonators
Filonenko, Konstantin; Duggen, Lars; Adam, Jost;
Metal nanowire resonators allow subwavelength mode confinement and thereby the strong Purcell effect. Recent progress in fabrication of plasmonic nanowire lasers requires reliable approaches in studying resonators, where metal nanowire is an essential constitutive element. A semi-analytic study......, capable of treating finite-length axially-symmetric nanowire configurations, was reported in. In some nanolaser configurations, however, one needs to treat asymmetric source distributions, e.g. the single quantum dot placed at some distance from the nanowire axis. We investigate the Purcell effect...... of the asymmetric source distributions in proximity to the metal nanowire in two configurations: a metal cylinder truncated by the PEC plates and finite metal cylinder in free-space. In order to evaluate Purcell factor the mode eigenvalues are precalculated using Comsol Multiphysics radio frequency module. We...
Purcell effect of asymmetric dipole source distributions in nanowire resonators
Filonenko, Konstantin; Duggen, Lars; Adam, Jost;
2015-01-01
Metal nanowire resonators allow subwavelength mode confinement and thereby the strong Purcell effect. Recent progress in fabrication of plasmonic nanowire lasers requires reliable approaches in studying resonators, where metal nanowire is an essential constitutive element. A semi-analytic study......, capable of treating finite-length axially-symmetric nanowire configurations, was reported in. In some nanolaser configurations, however, one needs to treat asymmetric source distributions, e.g. the single quantum dot placed at some distance from the nanowire axis. We investigate the Purcell effect...... of the asymmetric source distributions in proximity to the metal nanowire in two configurations: a metal cylinder truncated by the PEC plates and finite metal cylinder in free-space. In order to evaluate Purcell factor the mode eigenvalues are precalculated using Comsol Multiphysics radio frequency module. We...
Giant Dipole Resonance decay of hot rotating 88Mo
Ciemała M.
2014-03-01
Full Text Available An experiment focusing on study of the properties of hot rotating compound nucleus of 88Mo was performed in LNL Legnaro using 48Ti beam at energies of 300 and 600 MeV on 40Ca target. The compound nucleus was produced at the temperatures of 3 and 4.5 MeV, with angular momentum distribution with lmax > 60 ħ (i.e. exceeding the crtical angular momentum for fission. High-energy gamma rays, measured in coincidence with evaporation residues and alpha particles, were analyzed with the statistical model. The GDR parameters were obtained from the best fit to the data, which allowed investigating an evolution of the GDR width up to high temperatures.
Giant Dipole Resonance decay of hot rotating 88Mo
Ciemała, M.; Kmiecik, M.; Maj, A.; Kravchuk, V. L.; Gramegna, F.; Barlini, S.; Casini, G.; Camera, F.
2014-03-01
An experiment focusing on study of the properties of hot rotating compound nucleus of 88Mo was performed in LNL Legnaro using 48Ti beam at energies of 300 and 600 MeV on 40Ca target. The compound nucleus was produced at the temperatures of 3 and 4.5 MeV, with angular momentum distribution with lmax > 60 ħ (i.e. exceeding the crtical angular momentum for fission). High-energy gamma rays, measured in coincidence with evaporation residues and alpha particles, were analyzed with the statistical model. The GDR parameters were obtained from the best fit to the data, which allowed investigating an evolution of the GDR width up to high temperatures.
Mulyanti, B.; Ramza, H.; Pawinanto, R. E.; Rahman, J. A.; Ab-Rahman, M. S.; Putro, W. S.; Hasanah, L.; Pantjawati, A. B.
2017-05-01
The acid rain is an environmental disaster that it will be intimidates human life. The development micro-ring resonator sensor created from SOI (Silicon on insulator) and it used to detect acid rain index. In this study, the LUMERICAL software was used to simulate SOI material micro-ring resonator. The result shows the optimum values of fixed parameters from ring resonator have dependent variable in gap width. The layers under ring resonator with silicone (Si) and wafer layer of silicone material (Si) were added to seen three conditions of capability model. Model - 3 is an additional of bottom layer that gives the significant effect on the factor of quality. The optimum value is a peak value that given by the FSR calculation. FSR = 0, it means that is not shows the light propagation in the ring resonator and none of the light coming out on the bus - line.
The decay pattern of the Pygmy Dipole Resonance of ^{140} Ce
Löher, B.; Savran, D.; Aumann, T.; Beller, J.; Bhike, M.; Cooper, N.; Derya, V.; Duchêne, M.; Endres, J.; Hennig, A.; Humby, P.; Isaak, J.; Kelley, J. H.; Knörzer, M.; Pietralla, N.; Ponomarev, V. Yu.; Romig, C.; Scheck, M.; Scheit, H.; Silva, J.; Tonchev, A. P.; Tornow, W.; Wamers, F.; Weller, H.; Werner, V.; Zilges, A.
2016-05-01
The decay properties of the Pygmy Dipole Resonance (PDR) have been investigated in the semi-magic N=82 nucleus ^{140}Ce using a novel combination of nuclear resonance fluorescence and γ–γ coincidence techniques. Branching ratios for transitions to low-lying excited states are determined in a direct and model-independent way both for individual excited states and for excitation energy intervals. Comparison of the experimental results to microscopic calculations in the quasi-particle phonon model exhibits an excellent agreement, supporting the observation that the Pygmy Dipole Resonance couples to the ground state as well as to low-lying excited states. A 10% mixing of the PDR and the [21+×PDR] is extracted.
The decay pattern of the Pygmy Dipole Resonance of 140Ce
Löher, B.; Savran, D.; Aumann, T.; Beller, J.; Bhike, M.; Cooper, N.; Derya, V.; Duchêne, M.; Endres, J.; Hennig, A.; Humby, P.; Isaak, J.; Kelley, J. H.; Knörzer, M.; Pietralla, N.; Ponomarev, V. Yu.; Romig, C.; Scheck, M.; Scheit, H.; Silva, J.; Tonchev, A. P.; Tornow, W.; Wamers, F.; Weller, H.; Werner, V.; Zilges, A.
2016-05-01
The decay properties of the Pygmy Dipole Resonance (PDR) have been investigated in the semi-magic N = 82 nucleus 140Ce using a novel combination of nuclear resonance fluorescence and γ-γ coincidence techniques. Branching ratios for transitions to low-lying excited states are determined in a direct and model-independent way both for individual excited states and for excitation energy intervals. Comparison of the experimental results to microscopic calculations in the quasi-particle phonon model exhibits an excellent agreement, supporting the observation that the Pygmy Dipole Resonance couples to the ground state as well as to low-lying excited states. A 10% mixing of the PDR and the [21+ × PDR ] is extracted.
Excitation energy and strength of the pygmy dipole resonance in stable tin isotopes
Özel, B; Lenske, H; Von Neumann-Cosel, P; Poltoratska, I; Ponomarev, V Yu; Richter, A; Savran, D; Tsoneva, N
2009-01-01
The $^{112,120}$Sn$(\\gamma,\\gamma')$ reactions have been studied at the S-DALINAC. Electric dipole (E1) strength distributions have been determined including contributions from unresolved strength extracted by a fluctuation analysis. Together with available data on $^{116,124}$Sn, an experimental systematics of the pygmy dipole resonance (PDR) in stable even-mass tin isotopes is established. The PDR centroid excitation energies and summed strengths are in reasonable agreement with quasiparticle-phonon model calculations based on a nonrelativistic description of the mean field but disagree with relativistic quasiparticle random-phase approximation predictions.
Low-lying dipole resonance in neutron-rich Ne isotopes
Yoshida, Kenichi; van Giai, Nguyen
2008-07-01
Microscopic structure of the low-lying isovector dipole excitation mode in neutron-rich Ne26,28,30 is investigated by performing deformed quasiparticle-random-phase-approximation (QRPA) calculations. The particle-hole residual interaction is derived from a Skyrme force through a Landau-Migdal approximation. We obtain the low-lying resonance in Ne26 at around 8.6 MeV. It is found that the isovector dipole strength at ExThomas-Reiche-Kuhn dipole sum rule. This excitation mode is composed of several QRPA eigenmodes, one is generated by a ν(2s1/2-12p3/2) transition dominantly and the other mostly by a ν(2s1/2-12p1/2) transition. The neutron excitations take place outside of the nuclear surface reflecting the spatially extended structure of the 2s1/2 wave function. In Ne30, the deformation splitting of the giant resonance is large, and the low-lying resonance overlaps with the giant resonance.
Gamma-ray width measurements in {sup 15}N at the ELBE nuclear resonance fluorescence setup
Szuecs, Tamas [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); MTA ATOMKI, Debrecen/Hungary (Hungary); Bemmerer, Daniel; Schwengner, Ronald [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Massarczyk, Ralph; Takacs, Marcell; Wagner, Louis [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); TU Dresden (Germany)
2014-07-01
The stable nucleus {sup 15}N is the mirror of the astrophysically important {sup 15}O, compound nucleus of the leading reaction of the Bethe-Weizsaecker cycle of hydrogen burning. Most of the {sup 15}N level widths below the neutron and proton emission thresholds are known from just one nuclear resonance fluorescence (NRF) measurement published more than 30 years ago, with unsatisfactory precision on some cases. A recent experiment with the AGATA demonstrator array aimed to determine level widths with the Doppler Shift Attenuation Method (DSAM) in {sup 15}O and {sup 15}N populated in {sup 14}N + {sup 2}H reaction. In order to set a benchmark value for the upcoming AGATA demonstrator data, the widths of several {sup 15}N levels are being studied using the bremsstrahlung facility γELBE at the electron accelerator of Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The γELBE experiment and its preliminary results are presented.
Zero width resonance (spectral singularity) in a complex PT-symmetric potential
Ahmed, Zafar
2009-01-01
We show that the complex PT-Symmetric potential, $V(x)=-V_1 {sech}^2x + iV_2 {sech}x ~\\tanh x, $, entails a single zero-width resonance (spectral singularity) when $V_1+|V_2|=4n^2+4n+{3\\over 4}(n=1,2,3.., |V_2|>|V_1|+ {{sgn}(V_1) \\over 4})$ and the positive resonant energy is given as $E_*={1 \\over 4}[|V_2|-(1/4+V_1)]$.
Effect of thresholds on the width of three-body resonances
Garcilazo, H.; Valcarce, A.
2017-09-01
It has been recently reported an intriguing theoretical result of a narrow three-body resonance with a large available phase space [1]. The resonance was reported in the NΛΛ - ΞNN system near the Ξd threshold, having a very small width in spite of the open NΛΛ channel lying around 23 MeV below the ΞNN channel. We use first-order perturbation theory as a plausible argument to explain this behavior. We apply our result to realistic local interactions. Other systems involving several thresholds are likely to follow the same behavior.
Electric dipole strength distribution below the E1 giant resonance in N = 82 nuclei
Guliyev, Ekber; Kuliev, Ali; Guner, Mehmet
2010-12-01
In this study quasiparticle random-phase approximation with the translational invariant Hamiltonian using deformed mean field potential has been conducted to describe electric dipole excitations in 136Xe, 138Ba, 140Ce, 142Nd, 144Sm and 146Gd isotones. The distribution of the calculated E1 strength shows a resonance like structure at energies between 6-8 MeV exhausting up to 1% of the isovector electric dipole Energy Weighted Sum Rule and in some aspects nicely confirms the experimental data. It has been shown that the main part of E1 strength, observed below the threshold in these nuclei may be interpreted as main fragments of the Pygmy Dipole resonance. The agreement between calculated mean excitation energies as well as summed B(E1) value of the 1- excitations and the available experimental data is quite good. The calculations indicate the presence of a few prominent positive parity 1+ States in heavy N = 82 isotones in the energy interval 6-8 MeV which shows not all dipole excitations were of electric character in this energy range.
Szücs, Tamás
2015-01-01
The determination of absolute widths of two observed levels above the proton threshold in $^{15}$N has been improved by a combined analysis of our recent $^{15}$N($\\gamma$,$\\gamma'$)$^{15}$N$^\\ast$ photon scattering data, resonance strengths $\\omega\\gamma$ of the $^{14}$C($p$,$\\gamma$)$^{15}$N reaction, and $\\gamma$-ray branchings $b_{\\gamma,i}$ in $^{15}$N. The revised data are compared to the adopted values, and some inconsistencies in the adopted values are illustrated.
Determination of gamma-ray widths in $^{15}$N using nuclear resonance fluorescence
Szücs, T.; Bemmerer, D.; Caciolli, A.; Fülöp, Zs.; Massarczyk, R.; Michelagnoli, C.; Reinhardt, T. P.; Schwengner, R.; Takács, M. P.; Ur, C. A.; Wagner, A.; Wagner, L.
2015-01-01
The stable nucleus $^{15}$N is the mirror of $^{15}$O, the bottleneck in the hydrogen burning CNO cycle. Most of the $^{15}$N level widths below the proton emission threshold are known from just one nuclear resonance fluorescence (NRF) measurement, with limited precision in some cases. A recent experiment with the AGATA demonstrator array determined level lifetimes using the Doppler Shift Attenuation Method (DSAM) in $^{15}$O. As a reference and for testing the method, level lifetimes in $^{1...
The Giant Dipole Resonance built on highly excited states — results of the MEDEA experiment
Suomijärvi, T.; Le Faou, J. H.; Blumenfeld, Y.; Piattelli, P.; Agodi, C.; Alamanos, N.; Alba, R.; Auger, F.; Bellia, G.; Chomaz, Ph.; Coniglione, R.; Del Zoppo, A.; Finocchiaro, P.; Frascaria, N.; Gaardhøje, J. J.; Garron, J. P.; Gillibert, A.; Lamehi-Rachti, M.; Liguori-Neto, R.; Maiolino, C.; Migneco, E.; Russo, G.; Roynette, J. C.; Santonocito, D.; Sapienza, P.; Scarpaci, J. A.; Smerzi, A.
1994-03-01
Gamma-rays, light charged particles and evaporation residues emitted from hot nuclei formed in the 36Ar + 90Zr reaction at 27 MeV/u have been measured with a nearly 4π barium fluoride multidetector. It is shown that hot Sn-like nuclei with a range of excitation energies between 300 and 600 MeV are produced. The γ-ray yield from the decay of the Giant Dipole Resonance in these nuclei is shown to remain constant over this excitation energy range. The measured γ-ray spectra are compared with statistical calculations encompassing several recent theoretical models for the quenching of gamma-ray emission from the dipole resonance at very high temperatures.
Is the Double Giant Dipole Resonance Process Responsible for Alpha Emission in Ternary Fission?
Han, Hong-Yin; Wand, Yi-Hua; Mouze, G.
2001-11-01
The Monte Carlo program built on the double giant dipole resonance model proposed by Mouze et al. [Nuovo Cimento A 110(1997)1097] was employed to calculate the energy spectrum of alpha particles emitted in the spontaneous ternary fission of 252Cf. It has been found that in the case of the zero orbital angular momentum of alpha particles in the alpha decay of the fragments, the measured alpha spectrum can be reproduced approximately by the model without any adjustable parameter.
Is the Double Giant Dipole Resonance Process Responsible for Alpha Emission in Ternary Fission?
HAN Hong-Yin(韩洪银); WAND Yi-Hua(王屹华); G.Mouze
2001-01-01
The Monte Carlo program built on the double giant dipole resonance model proposed by Mouze et al. [Nuovo Cimento A 110(1997)1097] was employed to calculate the energy spectrum of alpha particles emitted in the spontaneous ternary fission of 252Cf. It has been found that in the case of the zero orbital angular momentum of alpha particles in the alpha decay of the fragments, the measured alpha spectrum can be reproduced approximately by the model without any adjustable parameter.
Direct proton decay and microscopic structure of the spin-dipole resonance in Bi-208
Akimune, H; Daito, [No Value; Fujita, Y; Fujiwara, M; Harakeh, MN; Janecke, J; Yosoi, M
2000-01-01
The microscopic structure of the spin-dipole resonance (SDR) at E-x = 21.1 MeV in Bi-208 has been investigated in the Pb-208(He-3,t)Bi-208 reaction at E(He-3) = 450 MeV and very forward scattering angles. Protons emitted due to the decay of the SDR were measured in solid-state detectors in coinciden
Musorin, A. I.; Barsukova, M. G.; Shorokhov, A. S.; Neshev, D. N.; Kivshar, Y. S.; Fedyanin, A. A.
2017-09-01
The advantages of gyrotopic materials are combined with the field of high-index metamaterials. The enhancement of the magneto-optical response in the spectral vicinity of the magnetic dipole resonance of a dielectric silicon nanodisks is numerically shown.
Time Asymmetric Boundary Conditions and the Definition of Mass and Width for Relativistic Resonances
Bohm, A R; Tay, B A; Kielanowski, Piotr
2001-01-01
The definition of mass and width of relativistic resonances and in particular of the $Z$-boson is discussed. For this we use the theory based on time asymmetric boundary conditions given by Hardy class spaces ${\\mathbf \\Phi}_-$ and ${\\mathbf \\Phi}_+$ for prepared in-states and detected out-states respectively, rather than time symmetric Hilbert space theory. This Hardy class boundary condition is a mathematically rigorous form of the singular Lippmann-Schwinger equation. In addition to the rigorous definition of the Lippmann-Schwinger kets $|[j,{\\mathsf s}]^{\\pm}>$ as functionals on the spaces ${\\mathbf \\Phi}_{\\mp}$, one obtains Gamow kets $|[j,{\\mathsf s}_R]^- >$ with complex centre-of-mass energy value ${\\mathsf s}_R=(M_R-i\\Gamma_R/2)^2$. The Gamow kets have an exponential time evolution given by $\\exp{(-iM_Rt-\\Gamma_Rt/2)}$ which suggests that $(M_R,\\Gamma_R)$ is the right definition of the mass and width of a resonance. This is different from the two definitions of the $Z$-boson mass and width used in the...
Band Width of Acoustic Resonance Frequency Relatively Natural Frequency of Fuel Rod Vibration
Proskuryakov, Konstantin Nicolaevich; Moukhine, V.S.; Novikov, K.S.; Galivets, E.Yu. [MPEI - TU, 14, Krasnokazarmennaya str., Moscow, 111250 (Russian Federation)
2009-06-15
In flow induced vibrations the fluid flow is the energy source that causes vibration. Acoustic resonance in piping may lead to severe problems due to over-stressing of components or significant losses of efficiency. Steady oscillatory flow in NPP primary loop can be induced by the pulsating flow introduced by reactor circulating pump or may be set up by self-excitation. Dynamic forces generated by the turbulent flow of coolant in reactor cores cause fuel rods (FR) and fuel assembly (FA) to vibrate. Flow-induced FR and FA vibrations can generally be broken into three groups: large amplitude 'resonance type' vibrations, which can cause immediate rod failure or severe damage to the rod and its support structure, middle amplitude 'within bandwidth of resonance frequency type' vibrations responsible for more gradual wear and fatigue at the contact surface between the fuel cladding and rod support and small amplitude vibrations, 'out of bandwidth of resonance frequency type' responsible for permissible wear and fatigue at the contact surface between the fuel cladding and rod support. Ultimately, these vibration types can result in a cladding breach, and therefore must be accounted for in the thermal hydraulic design of FR and FA and reactor internals. In paper the technique of definition of quality factor (Q) of acoustic contour of the coolant is presented. The value of Q defines a range of frequencies of acoustic fluctuations of the coolant within which the resonance of oscillations of the structure and the coolant is realized. Method of evaluation of so called band width (BW) of acoustic resonance frequency is worked out and presented in the paper. BW characterises the range of the frequency of coolant pressure oscillations within which the frequency of coolant pressure oscillations matches the fuel assembly's natural frequency of vibration (its resonance frequency). Paper show the way of detuning acoustic resonance from natural
Distribution of total radiation widths for neutron resonances of Pt isotopes
Koehler P.E.
2015-01-01
Full Text Available High quality neutron capture and transmission data were measured on isotopically enriched 192,194,195,196Pt and natural Pt samples at ORELA. R-matrix analysis of this data revealed resonance parameters for 159, 413, 423, 258, and 11 neutron resonances for neutron energies below 5.0, 16.0, 7.5, 16.0, and 5.0 keV for 192,194,195,196,198Pt+n, respectively. Earlier analysis of data on reduced neutron widths, Γ0n, showed that the distributions of Γ0n for 192,194Pt deviate significantly from the Porter-Thomas distribution (PTD predicted by random matrix theory. In this contribution we report on preliminary results of the analysis of distribution of total radiation widths, Γγ, in 192,194,195,196Pt+n reactions. Comparison of experimental data with predictions made within the nuclear statistical model indicates that standard models of Photon Strength Functions (PSFs and Nuclear Level Density predict Γγ distributions which are too narrow. We found that satisfactory agreement between experimental and simulated distributions can be obtained only by a strong suppression of the PSFs at low γ-ray energies and/or by violation of the usual assumption that primary transitions from neutron resonances follow the PTD. The shape of PSFs needed for reproduction of our Γγ data also nicely reproduces spectra from several (n,γ experiments on the neighbor nuclide 198Au.
Far-field resonance fluorescence from a dipole-interacting laser-driven cold atomic gas
Jones, Ryan; Saint, Reece; Olmos, Beatriz
2017-01-01
We analyze the temporal response of the fluorescence light that is emitted from a dense gas of cold atoms driven by a laser. When the average interatomic distance is comparable to the wavelength of the photons scattered by the atoms, the system exhibits strong dipolar interactions and collective dissipation. We solve the exact dynamics of small systems with different geometries and show how these collective features are manifest in the scattered light properties such as the photon emission rate, the power spectrum and the second-order correlation function. By calculating these quantities beyond the weak (linear) driving limit, we make progress in understanding the signatures of collective behavior in these many-body systems. Furthermore, we shed light on the role of disorder and averaging on the resonance fluorescence, of direct relevance for recent experimental efforts that aim at the exploration of many-body effects in dipole-dipole interacting gases of atoms.
Savran, D. [Institut fuer Kernphysik, TU Darmstadt, Schlossgartenstrasse 9, D-64289 Darmstadt (Germany); Babilon, M. [Institut fuer Kernphysik, TU Darmstadt, Schlossgartenstrasse 9, D-64289 Darmstadt (Germany); Berg, A.M. van den [Kernfysisch Versneller Instituut, Rijksuniversiteit Groningen, Zernikelaan 25, NL-9747 AA Groningen (Netherlands); Harakeh, M.N. [Kernfysisch Versneller Instituut, Rijksuniversiteit Groningen, Zernikelaan 25, NL-9747 AA Groningen (Netherlands); Hasper, J. [Institut fuer Kernphysik, TU Darmstadt, Schlossgartenstrasse 9, D-64289 Darmstadt (Germany); Woertche, H.J. [Kernfysisch Versneller Instituut, Rijksuniversiteit Groningen, Zernikelaan 25, NL-9747 AA Groningen (Netherlands); Zilges, A. [Institut fuer Kernphysik, TU Darmstadt, Schlossgartenstrasse 9, D-64289 Darmstadt (Germany)
2007-05-15
We report on first results from experiments using the ({alpha},{alpha}{sup '}{gamma}) reaction at E{sub {alpha}}=136 MeV to investigate bound electric dipole (E1) excitations building the so-called Pygmy Dipole Resonance (PDR) in the semi-magic nucleus {sup 140}Ce. The method of ({alpha},{alpha}{sup '}{gamma}) allows the separation of E1 excitations from states of higher multipolarity, provides an excellent energy resolution and therefore allows a detailed analysis for each single state. Studying bound E1 excitations in {alpha}-scattering experiments at intermediate energies becomes feasible for the first time even in nuclei with a high level density. The surprising results of the first experiment on {sup 140}Ce point to a splitting of the PDR in this nucleus.
Same but Different: Dipole-Stabilized Shape Resonances in CuF(-) and AgF(.).
Jagau, Thomas-C; Dao, Diep B; Holtgrewe, Nicholas S; Krylov, Anna I; Mabbs, Richard
2015-07-16
Electron attachment to closed-shell molecules is a gateway to various important processes in the gas and condensed phases. The properties of an electron-attached state, such as its energy and lifetime as well as the character of the molecular orbital to which the electron is attached, determine the fate of the anion. In this experimental and theoretical study of copper and silver fluoride anions, we introduce a new type of metastable anionic state. Abrupt changes in photoelectron angular distributions point to the existence of autodetaching states. Equation-of-motion coupled-cluster singles and doubles calculations augmented by a complex absorbing potential identify some of these states as Σ and Π dipole-stabilized resonances, a new type of shape resonance. In addition, these molecules support valence and dipole-bound states and a Σ resonance of charge-transfer character. By featuring five different types of anionic states, they provide a vehicle for studying fundamental properties of anions and for validating new theoretical approaches for metastable states.
Test of the Brink-Axel hypothesis for the pygmy dipole resonance
Martin, D; Tamii, A; Aoi, N; Bassauer, S; Bertulani, C A; Carter, J; Donaldson, L; Fujita, H; Fujita, Y; Hashimoto, T; Hatanaka, K; Ito, T; Krugmann, A; Liu, B; Maeda, Y; Miki, K; Neveling, R; Pietralla, N; Poltoratska, I; Ponomarev, V Yu; Richter, A; Shima, T; Yamamoto, T; Zweidinger, M
2016-01-01
The gamma strength function (GSF) and level density (LD) of 1- states in 96Mo have been extracted from a high-resolution study of the (p,p') reaction at 295 MeV and extreme forward angles. The GSF agrees with results of compound nucleus gamma decay experiments in the energy region of the Pygmy Dipole Resonance (PDR), validating the generalized Brink-Axel hypothesis commonly assumed in astrophysical reaction network calculations. The consistency of the LD deduced from the present data with those of the gamma decay experiments provides independent confirmation of the methods used to separate GSF and LD in Oslo-type experiments.
Neutron-skin thickness from the study of the anti-analog giant dipole resonance
2012-01-01
The gamma-decay of the anti-analog of the giant dipole resonance (AGDR) has been measured to the isobaric analog state excited in the p(124Sn,n) reaction at a beam energy of 600 MeV/nucleon. The energy of the transition was also calculated with state-of-the-art self-consistent random-phase approximation (RPA) and turned out to be very sensitive to the neutron-skin thickness (\\DeltaR_(pn)). By comparing the theoretical results with the measured one, the \\DeltaR_(pn) value for 124Sn was deduced...
Wieland, O; Bracco, A; Camera, F; Benzoni, G; Blasi, N; Brambilla, S; Crespi, F; Giussani, A; Leoni, S; Million, B; Moroni, A; Barlini, S; Kravchuk, V L; Gramegna, F; Lanchais, A; Mastinu, P; Maj, A; Brekiesz, M; Kmiecik, M; Bruno, M; Geraci, E; Vannini, G; Casini, G; Chiari, M; Nannini, A; Ordine, A; Ormand, W E
2006-06-16
The {gamma} decay of the Giant Dipole Resonance in the {sup 132}Ce compound nucleus with temperature up to {approx} 4 MeV has been measured. The symmetric {sup 64}Ni + {sup 68}Zn at E{sub beam} = 300, 400, 500 MeV and the asymmetric reaction {sup 16}O + {sup 116}Sn at E{sub beam} = 130, 250 MeV have been investigated. Light charged particles and {gamma} rays have been detected in coincidence with the recoiling compound system. In the case of the mass symmetric {sup 64}Ni induced reaction the {gamma} and charged particle spectral shapes are found to be consistent with the emission from a fully equilibrated compound nuclei and the GDR parameters are extracted from the data using a statistical model analysis. The GDR width is found to increase almost linear with temperature. This increase is rather well reproduced within a model which includes both the thermal fluctuation of the nuclear shape and the lifetime of the compound nucleus.
Development of the new gamma-ray calorimeter for the measurement of Pigmy Dipole Resonance
Shikata, Mizuki; Nakamura, Takashi; Togano, Yasuhiro; Kondo, Yosuke
2014-09-01
A new γ-ray calorimeter CATANA (CAlorimeter for gamma γ-ray Transition in Atomic Nuclei at high isospin Asynmetry) has been developed to measure highly excited states like the pygmy dipole resonance and the giant dipole resonance. CATANA will be used with the SAMURAI spectrometer at RIBF. The excitation energy spectrum will be reconstructed combining the invariant mass of the reaction products measured by SAMURAI and γ-ray energies from CATANA. CATANA has focused on achieving a high detection efficiency. It is calculated as 56% for 1 MeV γ-rays from beam with a velocity of β = 0.6. The CATANA array consists of 200 CsI(Na) crystals and covers angles from 10 to 120 degrees along the beam axis. In this study, we have tested prototype crystals of CATANA to evaluate their performance. A position dependence of the light input have been measured and compared with a Monte-Carlo simulation based on GEANT4. In this talk, we will report the design of CATANA and the result of the tests and the simulation.
Fosco, César D
2015-01-01
We study the properties of the classical electromagnetic (EM) radiation produced by two phys- ically different yet closely related systems, which may be regarded as classical analogues of the Dynamical Casimir Effect (DCE). They correspond to two flat, infinite, parallel planes, one of them static and imposing perfect conductor boundary conditions, while the other performs a rigid oscil- latory motion. The systems differ just in the electrical properties of the oscillating plane: one of them is just a planar dipole layer (representing, for instance, a small-width electret). The other, instead, has a dipole layer on the side which faces the static plane, but behaves as a conductor on the other side: this can be used as a representation of a conductor endowed with patch potentials (on the side which faces the conducting plane). We evaluate, in both cases, the dissipative flux of energy between the system and its environment, showing that, at least for small mechanical oscillation amplitudes, it can be written i...
Determining matrix elements and resonance widths from finite volume: the dangerous mu-terms
Takacs, G
2011-01-01
The standard numerical approach to determining matrix elements of local operators and width of resonances uses the finite volume dependence of energy levels and matrix elements. Finite size corrections that decay exponentially in the volume are usually neglected or taken into account using perturbation expansion in effective field theory. Using two-dimensional sine-Gordon field theory as "toy model" it is shown that some exponential finite size effects could be much larger than previously thought, potentially spoiling the determination of matrix elements in frameworks such as lattice QCD. The particular class of finite size corrections considered here are mu-terms arising from bound state poles in the scattering amplitudes. In sine-Gordon model, these can be explicitly evaluated and shown to explain the observed discrepancies to high precision. It is argued that the effects observed are not special to the two-dimensional setting, but rather depend on general field theoretic features that are common with model...
Jaouadi, Amine; Lefebvre, Roland; Atabek, Osman
2017-06-01
A semiclassical model supporting the destructive interference interpretation of zero-width resonances (ZWRs) is extended to wavelengths inducing c--type curve crossing situations in Na2 strong-field dissociation. This opens the possibility to get critical couples of wavelengths λ and field intensities I to reach ZWRs associated with the ground vibrationless level v =0 , that, contrary to other vibrational states (v >0 ), is not attainable for the commonly referred c+-type crossings. The morphology of such ZWRs in the laser (I ,λ ) parameter plane and their usefulness in filtration strategies aiming at molecular cooling down to the ground v =0 state are examined within the frame of an adiabatic transport scheme.
Determination of gamma-ray widths in $^{15}$N using nuclear resonance fluorescence
Szücs, T; Caciolli, A; Fülöp, Zs; Massarczyk, R; Michelagnoli, C; Reinhardt, T P; Schwengner, R; Takács, M P; Ur, C A; Wagner, A; Wagner, L
2015-01-01
The stable nucleus $^{15}$N is the mirror of $^{15}$O, the bottleneck in the hydrogen burning CNO cycle. Most of the $^{15}$N level widths below the proton emission threshold are known from just one nuclear resonance fluorescence (NRF) measurement, with limited precision in some cases. A recent experiment with the AGATA demonstrator array determined level lifetimes using the Doppler Shift Attenuation Method (DSAM) in $^{15}$O. As a reference and for testing the method, level lifetimes in $^{15}$N have also been determined in the same experiment. The latest compilation of $^{15}$N level properties dates back to 1991. The limited precision in some cases in the compilation calls for a new measurement in order to enable a comparison to the AGATA demonstrator data. The widths of several $^{15}$N levels have been studied with the NRF method. The solid nitrogen compounds enriched in $^{15}$N have been irradiated with bremsstrahlung. The $\\gamma$-rays following the deexcitation of the excited nuclear levels were dete...
Hu, Kan-Nian; Tycko, Robert
2009-07-28
We describe a method for measuring magnetic dipole-dipole interactions, and hence distances, between pairs of like nuclear spins in a many-spin system under magic-angle spinning (MAS). This method employs a homonuclear dipolar recoupling sequence that creates an average dipole-dipole coupling Hamiltonian under MAS with full zero-quantum symmetry, including both secular and flip-flop terms. Flip-flop terms are then attenuated by inserting rotor-synchronized periods of chemical shift evolution between recoupling blocks, leaving an effective Hamiltonian that contains only secular terms to a good approximation. Couplings between specific pairs of nuclear spins can then be selected with frequency-selective pi pulses. We demonstrate this technique, which we call zero-quantum shift evolution assisted homonuclear recoupling, in a series of one-dimensional and two-dimensional (13)C NMR experiments at 17.6 T and 40.00 kHz MAS frequency on uniformly (13)C-labeled L-threonine powder and on the helix-forming peptide MB(i+4)EK, synthesized with a pair of uniformly (13)C-labeled L-alanine residues. Experimental demonstrations include measurements of distances between (13)C sites that are separated by three bonds, placing quantitative constraints on both sidechain and backbone torsion angles in polypeptides.
Plane wave excitation-detection of non-resonant plasmons along finite-width graphene strips.
Gómez-Díaz, J S; Esquius-Morote, M; Perruisseau-Carrier, J
2013-10-21
An approach to couple free-space waves and non-resonant plasmons propagating along graphene strips is proposed based on the periodic modulation of the graphene strip width. The solution is technologically very simple, scalable in frequency, and provides customized coupling angle and intensity. Moreover, the coupling properties can be dynamically controlled at a fixed frequency via the graphene electrical field effect, enabling advanced and flexible plasmon excitation-detection strategies. We combine a previously derived scaling law for graphene strips with leaky-wave theory borrowed from microwaves to achieve rigorous and efficient modeling and design of the structure. In particular we analytically derive its dispersion, predict its coupling efficiency and radiated field structure, and design strip configurations able to fulfill specific coupling requirements. The proposed approach and developed methods are essential to the recent and fundamental problem of the excitation-detection of non-resonant plasmons propagating along a continuous graphene strip, and could pave the way to smart all-graphene sensors and transceivers.
Internal and external radiative widths in the combined R-matrix and potential model formalism
Mukhamedzhanov, A M; Bertulani, C A; Hao, T V Nhan
2016-01-01
Using the $R$-matrix approach we calculate the radiative width for a resonance decaying to a bound state through electric dipole, $E1$, transitions. The total radiative width is determined by the interference of the nuclear internal and external radiative width amplitudes. For a given channel radius the external radiative width amplitude is model independent and is determined by the asymptotic normalization coefficient (ANC) of the bound state to which the resonance decays. It also depends on the partial resonance width. To calculate the internal radiative width amplitude we show that a single particle potential model is appropriate. We compare our results with a few experimental data.
Nuclear spin cooling by electric dipole spin resonance and coherent population trapping
Li, Ai-Xian; Duan, Su-Qing; Zhang, Wei
2017-09-01
Nuclear spin fluctuation suppression is a key issue in preserving electron coherence for quantum information/computation. We propose an efficient way of nuclear spin cooling in semiconductor quantum dots (QDs) by the coherent population trapping (CPT) and the electric dipole spin resonance (EDSR) induced by optical fields and ac electric fields. The EDSR can enhance the spin flip-flop rate and may bring out bistability under certain conditions. By tuning the optical fields, we can avoid the EDSR induced bistability and obtain highly polarized nuclear spin state, which results in long electron coherence time. With the help of CPT and EDSR, an enhancement of 1500 times of the electron coherence time can been obtained after a 500 ns preparation time.
Structure and decay of the pygmy dipole resonance in 26Ne
Kimura, M
2016-01-01
The low-lying spectra of $^{24,25,26}{\\rm Ne}$ and the structure of the pygmy dipole resonance (PDR) in $^{26}{\\rm Ne}$ have been theoretically studied by the antisymmetrized molecular dynamics (AMD) and its extended version called shifted-basis AMD. The calculated energy and strength of the PDR reasonably agree with the observation, and the analysis of the wave function shows that the PDR is dominated by neutron excitation coupled to the quadrupole excited core nucleus $^{25}{\\rm Ne}$, which explains the observed unexpected decay of PDR to the excited states of $^{25}{\\rm Ne}$. The large isoscalar component of PDR is also shown and the enhancement of the core excitation in neutron-rich Ne isotopes is conjectured.
Multineutron photodisintegration of the {sup 197}Au nucleus behind the giant dipole resonance
Ermakov, A. N.; Ishkhanov, B. S.; Kapitonov, I. M.; Htun, Kyaw Kyaw; Makarenko, I. V.; Orlin, V. N.; Shvedunov, V. I. [Moscow State University, Institute of Nuclear Physics (Russian Federation)
2008-03-15
An experiment in which the gold isotope {sup 197}Au was irradiated with a beam of bremsstrahlung photons having an endpoint energy of E{sub {gamma}}{sup m} = 67.7 MeV and originating from the RTM-70 racetrack microtron of the Institute of Nuclear Physics at Moscow State University was performed. The gammaray spectra of the residual beta activity of an irradiated sample were measured. Multinucleon photonuclear reactions on {sup 197}Au nuclei were observed in the experiment. Photonuclear reactions on a {sup 197}Au nucleus that involve the emission of up to seven neutrons were recorded for the first time. The experimental results in question suggest the important role of the quasideuteron photodisintegration mechanism in the energy region behind the giant dipole resonance.
Multineutron photodisintegration of the 197Au nucleus behind the giant dipole resonance
Ermakov, A. N.; Ishkhanov, B. S.; Kapitonov, I. M.; Htun, Kyaw Kyaw; Makarenko, I. V.; Orlin, V. N.; Shvedunov, V. I.
2008-03-01
An experiment in which the gold isotope 197Au was irradiated with a beam of bremsstrahlung photons having an endpoint energy of E {/γ m } = 67.7 MeV and originating from the RTM-70 racetrack microtron of the Institute of Nuclear Physics at Moscow State University was performed. The gammaray spectra of the residual beta activity of an irradiated sample were measured. Multinucleon photonuclear reactions on 197Au nuclei were observed in the experiment. Photonuclear reactions on a 197Au nucleus that involve the emission of up to seven neutrons were recorded for the first time. The experimental results in question suggest the important role of the quasideuteron photodisintegration mechanism in the energy region behind the giant dipole resonance.
He, W B; Cao, X G; Cai, X Z; Zhang, G Q
2014-01-01
It is studied how the $\\alpha$ cluster degrees of freedom, such as $\\alpha$ clustering configurations close to the $\\alpha$ decay threshold in $^{12}$C and $^{16}$O, including the linear chain, triangle, square, kite, and tetrahedron, affect nuclear collective vibrations with a microscopic dynamical approach, which can describe properties of nuclear ground states well across the nuclide chart and reproduce the standard giant dipole resonance (GDR) of $^{16}$O quite nicely. It is found that the GDR spectrum is highly fragmented into several apparent peaks due to the $\\alpha$ structure. The different $\\alpha$ cluster configurations in $^{12}$C and $^{16}$O have corresponding characteristic spectra of GDR. The number and centroid energies of peaks in the GDR spectra can be reasonably explained by the geometrical and dynamical symmetries of $\\alpha$ clustering configurations. Therefore, the GDR can be regarded as a very effective probe to diagnose the different $\\alpha$ cluster configurations in light nuclei.
Leschhorn, G; Schaetz, T
2011-01-01
Two efficient and isotope-selective resonant two-photon ionization techniques for loading barium ions into radio-frequency (RF)-traps are demonstrated. The scheme of using a strong dipole-allowed transition at \\lambda=553 nm as a first step towards ionization is compared to the established technique of using a weak intercombination line (\\lambda=413 nm). An increase of two orders of magnitude in the ionization efficiency is found favoring the transition at 553 nm. This technique can be implemented using commercial all-solid-state laser systems and is expected to be advantageous compared to other narrowband photoionization schemes of barium in cases where highest efficiency and isotope-selectivity are required.
Origin of fine structure of the giant dipole resonance in sd-shell nuclei
Fearick, R W; Matsubara, H; von Neumann-Cosel, P; Richter, A; Roth, R; Tamii, A
2014-01-01
A set of high resolution zero-degree inelastic proton scattering data on 24Mg, 28Si, 32S, and 40Ca provides new insight into the long-standing puzzle of the origin of fragmentation of the Giant Dipole Resonance (GDR) in sd-shell nuclei. Understanding is provided by state-of-the-art theoretical Random Phase Approximation (RPA) calculatios for deformed nuclei using for the first time a realistic nucleon-nucleon interaction derived from the Argonne V18 potential with the unitary correlation operator method and supplemented by a phenomenological three-nucleon contact interaction. A wavelet analysis allows to extract significant scales both in the data and calculations characterizing the fine structure of the GDR. The fair agreement supports that the fine structure arises from ground-state deformation driven by alpha clustering.
Neutron-skin thickness from the study of the anti-analog giant dipole resonance
Krasznahorkay, A.; Stuhl, L.; Csatlós, M.; Algora, A.; Gulyás, J.; Timár, J.; Paar, N.; Vretenar, D.; Harakeh, M. N.; Boretzky, K.; Heil, M.; Litvinov, Yu. A.; Rossi, D.; Scheidenberger, C.; Simon, H.; Weick, H.; Bracco, A.; Brambilla, S.; Blasi, N.; Camera, F.; Giaz, A.; Million, B.; Pellegri, L.; Riboldi, S.; Wieland, O.; Altstadt, S.; Fonseca, M.; Glorius, J.; Göbel, K.; Heftrich, T.; Koloczek, A.; Kräckmann, S.; Langer, C.; Plag, R.; Pohl, M.; Rastrepina, G.; Reifarth, R.; Schmidt, S.; Sonnabend, K.; Weigand, M.; Kalantar-Nayestanaki, N.; Rigollet, C.; Bagchi, S.; Najafi, M. A.; Aumann, T.; Atar, L.; Heine, M.; Holl, M.; Movsesyan, A.; Schrock, P.; Volkov, V.; Wamers, F.; Fiori, E.; Löher, B.; Marganiec, J.; Savran, D.; Johansson, H. T.; Fernández, P. Diaz; Garg, U.; Balabanski, D. L.
2012-10-01
The γ-decay of the anti-analog of the giant dipole resonance (AGDR) to the isobaric analog state has been measured following the p(124Sn,n) reaction at a beam energy of 600 MeV/nucleon. The energy of the transition was also calculated with state-of-the-art self-consistent relativistic random-phase approximation (RPA) and turned out to be very sensitive to the neutronskin thickness (ΔRpn). By comparing the theoretical results with the measured one, the ΔRpn value for 124Sn was deduced to be 0.21 ± 0.07 fm, which agrees well with the previous results. The present method offers new possibilities for measuring the neutron-skin thicknesses of very exotic isotopes.
Kumar, A K Rhine; Dang, N Dinh
2015-01-01
Apart from the higher limits of isospin and temperature, the properties of atomic nuclei are intriguing and less explored at the limits of lowest but finite temperatures. At very low temperatures there is a strong interplay between the shell (quantal fluctuations), statistical (thermal fluctuations), and residual pairing effects as evidenced from the studies on giant dipole resonance (GDR). In our recent work [Phys. Rev. C \\textbf{90}, 044308 (2014)], we have outlined some of our results from a theoretical approach for such warm nuclei where all these effects are incorporated along within the thermal shape fluctuation model (TSFM) extended to include the fluctuations in the pairing field. In this article, we present the complete formalism based on the microscopic-macroscopic approach for determining the deformation energies and a macroscopic approach which links the deformation to GDR observables. We discuss our results for the nuclei $^{97}$Tc, $^{120}$Sn, $^{179}$Au, and $^{208}$Pb, and corroborate with the...
Silenko, Alexander J. [Belarusian State University, Research Institute for Nuclear Problems, Minsk (Belarus); Joint Institute for Nuclear Research, Bogoliubov Laboratory of Theoretical Physics, Dubna (Russian Federation)
2017-05-15
A general theoretical description of a magnetic resonance is presented. This description is necessary for a detailed analysis of spin dynamics in electric-dipole-moment experiments in storage rings. General formulas describing a behavior of all components of the polarization vector at the magnetic resonance are obtained for an arbitrary initial polarization. These formulas are exact on condition that the nonresonance rotating field is neglected. The spin dynamics is also calculated at frequencies far from resonance with allowance for both rotating fields. A general quantum-mechanical analysis of the spin evolution at the magnetic resonance is fulfilled and the full agreement between the classical and quantum-mechanical approaches is shown. Quasimagnetic resonances for particles and nuclei moving in noncontinuous perturbing fields of accelerators and storage rings are considered. Distinguishing features of quasimagnetic resonances in storage ring electric-dipole-moment experiments are investigated in detail. The exact formulas for the effect caused by the electric dipole moment are derived. The difference between the resonance effects conditioned by the rf electric-field flipper and the rf Wien filter is found and is calculated for the first time. The existence of this difference is crucial for the establishment of a consent between analytical derivations and computer simulations and for checking spin tracking programs. The main systematical errors are considered. (orig.)
Chou Chau, Yuan-Fong, E-mail: chou.fong@ubd.edu.bn; Lim, Chee Ming; Kumara, N. T. R. N.; Yoong, Voo Nyuk [Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Tungku Link, Gadong BE1410, Brunei (Brunei Darussalam); Lee, Chuanyo [Department of Electronic Engineering, Chien Hsin University of Science and Technology, No. 229, Jianxing Rd., Zhongli City, Taoyuan County 32097, Taiwan (China); Huang, Hung Ji; Lin, Chun-Ting [Instrument Technology Research Center, National Applied Research Laboratories, Hsinchu, Taiwan (China); Chiang, Hai-Pang [Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung 202, Taiwan (China)
2016-09-07
Tunable surface plasmon resonance (SPR) and dipole cavity plasmon modes of the scattering cross section (SCS) spectra on the single solid-gold/gold-shell nanorod have been numerically investigated by using the finite element method. Various effects, such as the influence of SCS spectra under x- and y-polarizations on the surface of the single solid-gold/gold-shell nanorod, are discussed in detail. With the single gold-shell nanorod, one can independently tune the relative SCS spectrum width by controlling the rod length and rod diameter, and the surface scattering by varying the shell thickness and polarization direction, as well as the dipole peak energy. These behaviors are consistent with the properties of localized SPRs and offer a way to optically control and produce selected emission wavelengths from the single solid-gold/gold-shell nanorod. The electric field and magnetic distributions provide us a qualitative idea of the geometrical properties of the single solid-gold/gold-shell nanorod on plasmon resonance.
Demekhina, N A; Karapetyan, G S
2001-01-01
The population of the isomeric states is considered in nuclei sup 1 sup 1 sup 5 In and sup 1 sup 8 sup 0 Hf in photonuclear (gamma, gamma') reactions at giant dipole resonance energies. The comparison with the earlier published experimental and theoretical data is made. The behavior of the excitation function gives an evidence for possible increase of the high-spin state population in the giant resonance range
Controlling vibrational cooling with zero-width resonances: An adiabatic Floquet approach
Leclerc, Arnaud; Viennot, David; Jolicard, Georges; Lefebvre, Roland; Atabek, Osman
2016-10-01
In molecular photodissociation, some specific combinations of laser parameters (wavelength and intensity) lead to unexpected zero-width resonances (ZWRs) with, in principle, infinite lifetimes. Their potential to induce basic quenching mechanisms has recently been devised in the laser control of vibrational cooling through filtration strategies [O. Atabek et al., Phys. Rev. A 87, 031403(R) (2013), 10.1103/PhysRevA.87.031403]. A full quantum adiabatic control theory based on the adiabatic Floquet Hamiltonian is developed to show how a laser pulse could be envelope-shaped and frequency-chirped so as to protect a given initial vibrational state against dissociation, taking advantage of its continuous transport on the corresponding ZWR all along the pulse duration. As compared with previous control scenarios that actually suffered from nonadiabatic contamination, drastically different and much more efficient filtration goals are achieved. A semiclassical analysis helps us to find and interpret a complete map of ZWRs in the laser parameter plane. In addition, the choice of a given ZWR path, among the complete series identified by the semiclassical approach, turns out to be crucial for the cooling scheme, targeting a single vibrational state population left at the end of the pulse, while all others have almost completely decayed. The illustrative example, which has the potential to be transposed to other diatomics, is Na2 prepared by photoassociation in vibrationally hot but translationally and rotationally cold states.
Barlini, S.; Kravchuk, V. L.; Wieland, O.; Bracco, A.; Gramegna, F.; Airoldi, A.; Benzoni, G.; Blasi, N.; Brambilla, S.; Brekiesz, M.; Bruno, M.; Camera, F.; Casini, G.; Chiari, M.; D'Agostino, M.; De Sanctis, J.; Geraci, E.; Kmiecik, M.; Lanchais, A.; Leoni, S.; Maj, A.; Mastinu, P. F.; Million, B.; Moroni, A.; Nannini, A.; Ordine, A.; Sacchi, R.; Vannini, G.
2006-08-01
Recent measurements have been performed at the National Laboratoty of Legnaro using mass-symmetric (400, 500 MeV 64Ni + 68Zn) and mass-asymmetric (250 MeV 16O + 116Sn) entrance channel reactions to form 132Ce compound nucleus at different excitation energies (E*=150, 200 and 200 MeV, respectively). The decay of the composite system has been followed studying the γ-rays and Light Charged Particles (LCP) spectra emitted in coincidence with the Evaporation Residues (ER). In this way the emission mechanism of the LCP, depending on the mass-asymmetry at the entrance channel and on the projectile energy, and the results of the Full Width Half-Maximum (FWHM) of the Giant Dipole Resonance as a function of the nuclear temperature have been studied.
Brazhnikov, D V; Yudin, V I
2014-01-01
The method for observing the high-contrast and narrow-width resonances of electromagnetically induced absorption (EIA) in the Hanle configuration under counterpropagating light waves is proposed. We theoretically analyze the absorption of a probe light wave in presence of counterpropagating one with the same frequency as the function of a static magnetic field applied along the vectors of light waves, propagating in a vapour cell. Here, as an example, we study a "dark" type of atomic dipole transition Fg=1-->Fe=1 in D1 line of 87Rb, where usually the electromagnetically induced transparency (EIT) can be observed. To obtain the EIA signal one should proper chose the polarizations of light waves and intensities. In contrast of regular schemes for observing EIA signals (in a single travelling light wave in the Hanle configuration or in a bichromatic light field consisted of two travelling waves), the proposed scheme allows one to use buffer gas to significantly enhance properties of the resonance. Also the drama...
Scheck, M.; Ponomarev, V. Yu.; Fritzsche, M.; Joubert, J.; Aumann, T.; Beller, J.; Isaak, J.; Kelley, J. H.; Kwan, E.; Pietralla, N.; Raut, R.; Romig, C.; Rusev, G.; Savran, D.; Schorrenberger, L.; Sonnabend, K.; Tonchev, A. P.; Tornow, W.; Weller, H. R.; Zilges, A.; Zweidinger, M.
2013-10-01
Background: Within the last decade, below the giant dipole resonance the existence of a concentration of additional electric dipole strength has been established. This accumulation of low-lying E1 strength is commonly referred to as pygmy dipole resonance (PDR).Purpose: The photoresponse of 60Ni has been investigated experimentally and theoretically to test the evolution of the PDR in a nucleus with only a small neutron excess. Furthermore, the isoscalar and isovector M1 resonances were investigated.Method: Spin-1 states were excited by exploiting the (γ,γ') nuclear resonance fluorescence technique with unpolarized continuous bremsstrahlung as well as with fully linearly polarized, quasimonochromatic, Compton-backscattered laser photons in the entrance channel of the reaction.Results: Up to 10 MeV a detailed picture of J=1 levels was obtained. For the preponderant number of the individual levels spin and parity were firmly assigned. Furthermore, branching ratios, transition widths, and reduced B(E1) or B(M1) excitation probability were calculated from the measured scattering cross sections. A comparison with theoretical results obtained within the quasiparticle phonon model allows an insight into the microscopic structure of the observed states.Conclusions: Below 10 MeV the directly observed E1 strength [∑B(E1)↑=(153.8±9.5) e2(fm)2] exhausts 0.5% of the Thomas-Reiche-Kuhn sum rule. This value increases to 0.8% of the sum rule [∑B(E1)↑=(250.9±31.1) e2(fm)2] when indirectly observed branches to lower-lying levels are considered. Two accumulations of M1 excited spin-1 states near 8 and 9 MeV excitation energy are identified as isoscalar and isovector M1 resonances dominated by proton and neutron f7/2→f5/2 spin-flip excitations. The B(M1)↑ strength of these structures accumulates to 3.94(27)μN2.
Measurement of the air gap width between double-deck metal layers based on surface plasmon resonance
Wu, Pao-Tung; Wu, Meng-Chyi; Wu, Chien-Ming
2010-04-01
In this article, we verify that the traditional Kretschmann-Raether configuration of surface plasmon resonance (SPR) could be used to measure the air gap width between a gold-plated prism and another gold-plated glass slide. Due to the presence of double-deck metal layers, the Fabry-Perot resonance and surface plasmon tunnel-coupled effects could occur, which would cause the SPR angle to begin to shift at a larger air gap width of about 700 nm as compared to the case of single metal layer with an air gap width of about 350 nm. The simulated results reveal that the SPR angle begins monotonically to shift initially from 44.5° to 46° when the air gap width between double-deck metal layers decreases from 700 to 500 nm. The smallest air gap width is measured to be 539 nm, in which the SPR angle is 45.5°, by fitting the simulated curves to the experimental results.
Spin gated GDR widths at moderate temperatures
Mukul Ish
2015-01-01
Full Text Available We present the evolution of giant dipole resonance (GDR width as a function of angular momentum in the compound nucleus 144Sm in the temperature range of 1.5-2.0 MeV. The high energy γ rays emitted from the decay of excited 144Sm were measured using large NaI detector in coincidence with 4π sum spin spectrometer. GDR widths were found to comply with thermal shape fluctuation model in this temperature range over a wide range of spin. Experimental widths tend to increase rapidly at high angular momentum values.
Nord, A.; Schiller, A.; Eckert, T.; Beck, O.; Besserer, J.; von Brentano, P.; Fischer, R.; Herzberg, R.; Jaeger, D.; Kneissl, U.; Margraf, J.; Maser, H.; Pietralla, N.; Pitz, H.H.; Rittner, M.; Zilges, A. [Institut fuer Strahlenphysik, Universitaet Stuttgart, Allmandring 3, D-70569 Stuttgart (Germany)]|[Institut fuer Kernphysik, Universitaet zu Koeln, Zuelpicher Strasse 77, D-50937 Koeln (Germany)
1996-11-01
Nuclear resonance fluorescence experiments were performed on the rare earth nuclei {sup 155}Gd and {sup 159}Tb to study the fragmentation of the {ital M}1 {ital scissors} {ital mode} in {ital odd} deformed nuclei and to establish a kind of systematics. Using the bremsstrahlung photon beam of the Stuttgart Dynamitron (end point energy 4.1 MeV) and high resolution Ge-{gamma} spectrometers detailed information was obtained on excitation energies, decay widths, transition probabilities, and branching ratios. The results are compared to those observed recently for the neighboring odd nuclei {sup 161,163}Dy and {sup 157}Gd. Whereas in the odd Dy isotopes the dipole strength is rather concentrated, both Gd isotopes show a strong fragmentation of the strength into about 25 ({sup 155}Gd) and 90 transitions ({sup 157}Gd) in the energy range 2{endash}4 MeV. The nucleus {sup 159}Tb linking the odd Dy and Gd isotopes exhibits an intermediate strength fragmentation. In general the observed total strength in the odd nuclei is reduced by a factor of 2{endash}3 as compared to their neighboring even-even isotopes. The different fragmentation behavior of the dipole strengths in the odd Dy and Gd isotopes is unexplained up to now. {copyright} {ital 1996 The American Physical Society.}
Nord, A.; Schiller, A.; Eckert, T.; Beck, O.; Besserer, J.; von Brentano, P.; Fischer, R.; Herzberg, R.-D.; Jäger, D.; Kneissl, U.; Margraf, J.; Maser, H.; Pietralla, N.; Pitz, H. H.; Rittner, M.; Zilges, A.
1996-11-01
Nuclear resonance fluorescence experiments were performed on the rare earth nuclei 155Gd and 159Tb to study the fragmentation of the M1 scissors mode in odd deformed nuclei and to establish a kind of systematics. Using the bremsstrahlung photon beam of the Stuttgart Dynamitron (end point energy 4.1 MeV) and high resolution Ge-γ spectrometers detailed information was obtained on excitation energies, decay widths, transition probabilities, and branching ratios. The results are compared to those observed recently for the neighboring odd nuclei 161,163Dy and 157Gd. Whereas in the odd Dy isotopes the dipole strength is rather concentrated, both Gd isotopes show a strong fragmentation of the strength into about 25 (155Gd) and 90 transitions (157Gd) in the energy range 2-4 MeV. The nucleus 159Tb linking the odd Dy and Gd isotopes exhibits an intermediate strength fragmentation. In general the observed total strength in the odd nuclei is reduced by a factor of 2-3 as compared to their neighboring even-even isotopes. The different fragmentation behavior of the dipole strengths in the odd Dy and Gd isotopes is unexplained up to now.
Electric dipole spin resonance in systems with a valley-dependent g factor
Rančić, Marko J.; Burkard, Guido
2016-05-01
In this theoretical study we qualitatively and quantitatively investigate the electric dipole spin resonance (EDSR) in a single Si/SiGe quantum dot in the presence of a magnetic field gradient, e.g., produced by a ferromagnet. We model a situation in which the control of electron spin states is achieved by applying an oscillatory electric field, inducing real-space oscillations of the electron inside the quantum dot. One of the goals of our study is to present a microscopic theory of valley-dependent g factors in Si/SiGe quantum dots and investigate how valley relaxation combined with a valley-dependent g factor leads to a novel electron spin dephasing mechanism. Furthermore, we discuss the interplay of spin and valley relaxations in Si/SiGe quantum dots. Our findings suggest that the electron spin dephases due to valley relaxation, and are in agreement with recent experimental studies [Nat. Nanotechnol. 9, 666 (2014), 10.1038/nnano.2014.153].
Signature of clustering in quantum many-body systems probed by the giant dipole resonance
Pandit, Deepak; Mondal, Debasish; Dey, Balaram; Bhattacharya, Srijit; Mukhopadhyay, S.; Pal, Surajit; De, A.; Banerjee, S. R.
2017-03-01
The present experimental study illustrates how large deformations attained by nuclei due to cluster formation are perceived through the giant dipole resonance (GDR) strength function. The high energy GDR γ rays have been measured from 32S at different angular momenta (J ) but similar temperatures in the reactions 4He(Elab=45 MeV )+28Si and 20Ne(Elab=145 MeV )+12C . The experimental data at lower J (˜10 ℏ ) suggests a normal deformation, similar to the ground state value, showing no potential signature of clustering. However, it is found that the GDR lineshape is fragmented into two prominent peaks at high J (˜20 ℏ ) providing a direct measurement of the large deformation developed in the nucleus. The observed lineshape is also completely different from the ones seen for Jacobi shape transition at high J pointing towards the formation of cluster structure in superdeformed states of 32S at such high spin. Thus, the GDR can be regarded as a unique tool to study cluster formation at high excitation energies and angular momenta.
Quenching of the Giant Dipole Resonance Strength at High Excitation Energy
Santonocito, D. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Blumenfeld, Y. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay (France); Agodi, C. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Alba, R. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Bellia, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Dipartimento di Fisica e Astronomia dell' Universita di Catania, via S. Sofia 64, I-95123 Catania (Italy); Coniglione, R. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Delaunay, F. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay (France); Del Zoppo, A. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Finocchiaro, P. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Frascaria, N. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay (France); Hongmei, F. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Lima, V. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay (France); Maiolino, C. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Migneco, E. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Dipartimento di Fisica e Astronomia dell' Universita di Catania, via S. Sofia 64, I-95123 Catania (Italy); Piattelli, P. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Sapienza, P. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Scarpaci, J.A. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay (France)
2007-05-15
The evolution with excitation energy of the Giant Dipole Resonance features in nuclei of mass A{approx}108-136 is reviewed. We first discuss the results of the experiments performed with MEDEA studying the GDR gamma decay from hot nuclei populated at excitation energies above 300 MeV. The focus of the paper is on the excitation energy region between 160 and 290 MeV. This region has been investigated through the study of the reactions {sup 116}Sn + {sup 12}C at 17 and 23A MeV, and {sup 116}Sn + {sup 24}Mg at 17A MeV. Gamma-rays were detected using MEDEA in coincidence with evaporation residues detected in MACISTE. The analysis of the gamma-ray spectra and their comparison with statistical calculations are presented. The comparison with {gamma}-ray spectra from the reaction {sup 36}Ar + {sup 98}Mo at higher excitation energies shows a coherent scenario where a progressive reduction of {gamma} multiplicity relative to predictions for 100% of the Energy Weighted Sum Rule is observed above 200 MeV excitation energy. Finally, the existence of a link between disappearance of collective motion and the liquid-gas phase transitions is discussed.
Neutron-skin thickness from the study of the antianalog giant dipole resonance
Krasznahorkay, A; Csatlós, M; Algora, A; Gulyás, J; Timár, J; Paar, N; Vretenar, D; Boretzky, K; Heil, M; Litvinov, Yu A; Rossi, D; Scheidenberger, C; Simon, H; Weick, H; Bracco, A; Brambilla, S; Blasi, N; Camera, F; Giaz, A; Million, B; Pellegri, L; Riboldi, S; Wieland, O; Altstadt, S; Fonseca, M; Glorius, J; Göbel, K; Heftrich, T; Koloczek, A; Kräckmann, S; Langer, C; Plag, R; Pohl, M; Rastrepina, G; Reifarth, R; Schmidt, S; Sonnabend, K; Weigand, M; Harakeh, M N; Kalantar-Nayestanaki, N; Rigollet, C; Bagchi, S; Najafi, M A; Aumann, T; Atar, L; Heine, M; Holl, M; Movsesyan, A; Schrock, P; Volkov, V; Wamers, F; Fiori, E; Löher, B; Marganiec, J; Savaran, D; Johansson, H T; Fernández, P Diaz; Garg, U; Balabanski, D L
2012-01-01
The gamma-decay of the anti-analog of the giant dipole resonance (AGDR) has been measured to the isobaric analog state excited in the p(124Sn,n) reaction at a beam energy of 600 MeV/nucleon. The energy of the transition was also calculated with state-of-the-art self-consistent random-phase approximation (RPA) and turned out to be very sensitive to the neutron-skin thickness (\\DeltaR_(pn)). By comparing the theoretical results with the measured one, the \\DeltaR_(pn) value for 124Sn was deduced to be 0.18 \\pm 0.02 fm, which agrees well with the previous results. The energy of the AGDR measured previously for ^(208)Pb was also used to determine the \\DeltaR_(pn) for ^(208)Pb. In this way a very precise \\DeltaR_(pn) = 0.18 \\pm 0.02 neutron-skin thickness has been obtained for 208Pb. The present method offers new possibilities for measuring the neutron-skin thicknesses of very exotic isotopes.
Hu, Fangrong; Xu, Ningning; Wang, Weiming; Wang, Yue'e.; Zhang, Wentao; Han, Jiaguang; Zhang, Weili
2016-02-01
We experimentally demonstrate a dynamically tunable terahertz (THz) metamaterial absorber based on an electrostatic microelectromechanical systems (MEMS) actuator and electrical dipole resonator array. The absorption of the THz wave is mainly a result of the electrical dipole resonance, which shows a tunable performance on demand. By preforming the finite integral technique, we discovered that the central absorption frequency and the amplitude can be simultaneously tuned by the applied voltage U. Characterized by a white light interferometer and a THz time domain spectroscopy system, our THz absorber is measured to show a modulation of the central frequency and the amplitude to about 10% and 20%, respectively. The experimental results show good agreement with the simulation. This dynamically tunable absorber has potential applications on THz filters, modulators and controllers.
Shimada, Rintaro; Hamaguchi, Hiro-o, E-mail: hhama@nctu.edu.tw [Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan (China)
2014-05-28
We quantitatively interpret the recently discovered intriguing phenomenon related to resonance Hyper-Raman (HR) scattering. In resonance HR spectra of all-trans-β-carotene (β-carotene) in solution, vibrations of proximate solvent molecules are observed concomitantly with the solute β-carotene HR bands. It has been shown that these solvent bands are subject to marked intensity enhancements by more than 5 orders of magnitude under the presence of β-carotene. We have called this phenomenon the molecular-near field effect. Resonance HR spectra of β-carotene in benzene, deuterated benzene, cyclohexane, and deuterated cyclohexane have been measured precisely for a quantitative analysis of this effect. The assignments of the observed peaks are made by referring to the infrared, Raman, and HR spectra of neat solvents. It has been revealed that infrared active and some Raman active vibrations are active in the HR molecular near-field effect. The observed spectra in the form of difference spectra (between benzene/deuterated benzene and cyclohexane/deuterated cyclohexane) are quantitatively analyzed on the basis of the extended vibronic theory of resonance HR scattering. The theory incorporates the coupling of excited electronic states of β-carotene with the vibrations of a proximate solvent molecule through solute–solvent dipole–dipole and dipole–quadrupole interactions. It is shown that the infrared active modes arise from the dipole–dipole interaction, whereas Raman active modes from the dipole–quadrupole interaction. It is also shown that vibrations that give strongly polarized Raman bands are weak in the HR molecular near-field effect. The observed solvent HR spectra are simulated with the help of quantum chemical calculations for various orientations and distances of a solvent molecule with respect to the solute. The observed spectra are best simulated with random orientations of the solvent molecule at an intermolecular distance of 10 Å.
Isoscalar monopole and dipole excitations of cluster states and giant resonances in 12C
Kanada-En'yo, Yoshiko
2016-05-01
The isoscalar monopole (ISM) and dipole (ISD) excitations in 12C are investigated theoretically with the shifted antisymmetrized molecular dynamics (AMD) plus 3 α -cluster generator coordinate method (GCM). The small-amplitude vibration modes are described by coherent one-particle one-hole excitations expressed by a small shift of single-nucleon Gaussian wave functions within the AMD framework, whereas the large-amplitude cluster modes are incorporated by superposing 3 α -cluster wave functions in the GCM. The coupling of the excitations in the intrinsic frame with the rotation and parity transformation is taken into account microscopically by the angular-momentum and parity projections. The present a calculation that describes the ISM and ISD excitations over a wide energy region covering cluster modes in the low-energy region and the giant resonances in the high-energy region, although the quantitative description of the high-energy part is not satisfactory. The low-energy ISM and ISD strengths of the cluster modes are enhanced by the distance motion between α clusters, and they split into a couple of states because of the angular motion of α clusters. The low-energy ISM strengths exhaust 26% of the energy-weighted sum rule, which is consistent with the experimental data for the 12C(02+; 7.65 MeV) and 12C(03+; 10.3 MeV) measured by (e ,e') ,(α ,α') , and (6Li,6Li' ) scatterings. In the calculated low-energy ISD strengths, two 1- states (the 11- and 12- states) with the significant strengths are obtained over E =10 -15 MeV. The results indicate that the ISD excitations can be a good probe to experimentally search for new cluster states such as the 12C(12-) obtained in the present calculation.
Nature of low-lying electric dipole resonance excitations in 74Ge
Negi, D; Lanza, E G; Litvinova, E; Vitturi, A; Bark, R A; Bernstein, L A; Bleuel, D L; Bvumbi, S; Bucher, T D; Daub, B H; Dinoko, T S; Easton, J L; Gorgen, A; Guttormsen, M; Jones, P; Kheswa, B V; Khumalo, N A; Larsen, A C; Lawrie, E A; Lawrie, J J; Majola, S N T; Masiteng, L P; Nchodu, M R; Ndayishimye, J; Newman, R T; Noncolela, S P; Orce, J N; Papka, P; Pellegri, L; Renstrøm, T; Roux, D G; Schwengner, R; Shirinda, O; Siem, S
2016-01-01
Isospin properties of dipole excitations in 74 Ge are investigated using the ({\\alpha},{\\alpha}'{\\gamma}) reaction and compared to ({\\gamma},{\\gamma}) data. The results indicate that the dipole excitations in the energy region of 6 to 9 MeV adhere to the scenario of the recently found splitting of the region of dipole excitations into two separated parts: one at low energy, being populated by both isoscalar and isovector probes, and the other at high energy, excited only by the electromagnetic probe. Relativistic quasiparticle time blocking approximation (RQTBA) calculations show a reduction in the isoscalar E1 strength with an increase in excitation energy, which is consistent with the measurement.
Sub-natural width resonances in Cs vapor confined in micrometric thickness optical cell
Cartaleva, S.; Krasteva, A.; Sargsyan, A.; Sarkisyan, D.; Slavov, D.; Vartanyan, T.
2013-03-01
We present here the behavior of Electromagnetically Induced Transparency (EIT), Velocity Selective Optical Pumping (VSOP) resonances and Velocity Selective Excitation (VSE) resonances observed in Cs vapor confined in а micrometric optical cell (MC) with thickness L = 6λ, λ = 852nm. For comparison of behavior of VSE resonance another conventional optical cell with thickness L=2.5 cm is used. Cells are irradiated in orthogonal to their windows directions by probe beam scanned on the Fg = 4 → Fe= 3, 4, 5 set of transitions and pump beam fixed at the Fg = 3 → Fe = 4 transition, on the D2 line of Cs. The enhanced absorption (fluorescence) narrow VSOP resonance at the closed transition transforms into reduced absorption (fluorescence) one with small increase of atomic concentration or light intensity. A striking difference appears between the VSE resonance broadening in L = 6λ and conventional L = 2.5cm cells.
Effects of finite pulse width on two-dimensional Fourier transform electron spin resonance
Liang, Zhichun; Crepeau, Richard H.; Freed, Jack H.
2005-12-01
Two-dimensional (2D) Fourier transform ESR techniques, such as 2D-ELDOR, have considerably improved the resolution of ESR in studies of molecular dynamics in complex fluids such as liquid crystals and membrane vesicles and in spin labeled polymers and peptides. A well-developed theory based on the stochastic Liouville equation (SLE) has been successfully employed to analyze these experiments. However, one fundamental assumption has been utilized to simplify the complex analysis, viz. the pulses have been treated as ideal non-selective ones, which therefore provide uniform irradiation of the whole spectrum. In actual experiments, the pulses are of finite width causing deviations from the theoretical predictions, a problem that is exacerbated by experiments performed at higher frequencies. In the present paper we provide a method to deal with the full SLE including the explicit role of the molecular dynamics, the spin Hamiltonian and the radiation field during the pulse. The computations are rendered more manageable by utilizing the Trotter formula, which is adapted to handle this SLE in what we call a "Split Super-Operator" method. Examples are given for different motional regimes, which show how 2D-ELDOR spectra are affected by the finite pulse widths. The theory shows good agreement with 2D-ELDOR experiments performed as a function of pulse width.
Oh, S.Y.
2001-02-02
The SUGGEL computer code has been developed to suggest a value for the orbital angular momentum of a neutron resonance that is consistent with the magnitude of its neutron width. The suggestion is based on the probability that a resonance having a certain value of g{Gamma}{sub n} is an l-wave resonance. The probability is calculated by using Bayes' theorem on the conditional probability. The probability density functions (pdf's) of g{Gamma}{sub n} for up to d-wave (l=2) have been derived from the {chi}{sup 2} distribution of Porter and Thomas. The pdf's take two possible channel spins into account. This code is a tool which evaluators will use to construct resonance parameters and help to assign resonance spin. The use of this tool is expected to reduce time and effort in the evaluation procedure, since the number of repeated runs of the fitting code (e.g., SAMMY) may be reduced.
Protsenko, I E; Uskov, A V; Krotova, K E [Lebedev Physical Institute, Leninsky prospect 53, Moscow (Russian Federation); O' Reilly, E P [Tyndall National Institute, ' Lee Maltings' , Prospect Row, Cork (Ireland)], E-mail: protsen@sci.lebedev.ru, E-mail: protsenk@gmail.com
2008-03-15
Theoretically predicted 'dipole lasing', i.e., spontaneous excitation of coherent metal nano-particle dipole oscillations through interaction with a quantum-dot two-level system subject to population inversion is demonstrated. Equations for dipole lasing are the same as equations for ordinary laser, where the dipole momentum of nano-particle stands for the electromagnetic field cavity mode. Dipole lasing frequency corresponds to the localized plasmon resonance of the nano-particle. Dipole momentum of nano-particle leads to coherent dipole radiation. Optical cavity is not necessary, the size of the dipole laser can be smaller than the optical wavelength, i.e. it is dipole nano-laser. Threshold conditions and optical bistability in dipole nano-lasers are considered.
On a possible large width 750 GeV diphoton resonance at ATLAS and CMS
Aloni, Daniel; Blum, Kfir; Dery, Avital; Efrati, Aielet; Nir, Yosef
2016-08-01
The ATLAS and CMS experiments at the LHC have reported an excess of diphoton events with invariant mass around 750 GeV, with local significance of about 3.6 σ and 2.6 σ, respectively. We entertain the possibility that this excess is due to new physics, in which case the data suggest a new particle with 13 TeV LHC production cross section times diphoton branching ratio of about 5 fb. Interestingly, ATLAS reports a mild preference for a sizeable width for the signal of about 45 GeV; this result appears consistent with CMS, and is further supported by improving the compatibility of the 8 TeV and 13 TeV analyses. We focus on the possibility that the new state is a scalar. First, we show that, in addition to the new state that is needed directly to produce the diphoton bump, yet more new particles beyond the Standard Model are needed to induce diphoton decay rate of the right size. Second, we note that if the excess is attributed to the Breit-Wigner peak of a single new state, then the signal strength and width — taken together — suggest a total LHC production cross section of order 105 fb. Restricting to perturbative models without ad-hoc introduction of many new states or exotic charges, we reach the following conclusions: (i) Gluon-fusion cannot explain the required large production cross section. (ii) Tree level production from initial state quarks cannot explain the required branching ratio to two photons. (iii) Tree level production is constrained by flavor data as well as LHC Run-I and Tevatron dijet analyses. Insisting on a large width we are led to suggest that more than one scalar states, nearly degenerate in mass, could conspire to produce an observed wide bump.
Papp, P.; Matejčík, Š.; Mach, P.; Urban, J.; Paidarová, I.; Horáček, J.
2013-06-01
The method of analytic continuation in the coupling constant (ACCC) in combination with use of the statistical Padé approximation is applied to the determination of resonance energy and width of some amino acids and formic acid dimer. Standard quantum chemistry codes provide accurate data which can be used for analytic continuation in the coupling constant to obtain the resonance energy and width of organic molecules with a good accuracy. The obtained results are compared with the existing experimental ones.
The reaction gammap-->pi0gamma'p and the magnetic dipole moment of the Delta+ 1232 resonance.
Kotulla, M; Ahrens, J; Annand, J R M; Beck, R; Caselotti, G; Fog, L S; Hornidge, D; Janssen, S; Krusche, B; McGeorge, J C; McGregor, I J D; Mengel, K; Messchendorp, J G; Metag, V; Novotny, R; Pfeiffer, M; Rost, M; Sack, S; Sanderson, R; Schadmand, S; Watts, D P
2002-12-30
The reaction gammap-->pi(0)gamma'p has been measured with the TAPS calorimeter at the Mainz Microtron accelerator facility MAMI for energies between sqrt[s]=1221-1331 MeV. The cross section's differential in angle and energy have been determined for the photon gamma' in three bins of the excitation energy. This reaction channel provides access to the magnetic dipole moment of the Delta(+)(1232) resonance and, for the first time, a value of mu(Delta(+))=[2.7(+1.0)(-1.3)(stat)+/-1.5(syst)+/-3(theor)]mu(N) has been extracted.
Measurement of the Am241(γ,n)Am240 reaction in the giant dipole resonance region
Tonchev, A. P.; Hammond, S. L.; Howell, C. R.; Huibregtse, C.; Hutcheson, A.; Kelley, J. H.; Kwan, E.; Raut, R.; Rusev, G.; Tornow, W.; Kawano, T.; Vieira, D. J.; Wilhelmy, J. B.
2010-11-01
The photodisintegration cross section of the radioactive nucleus Am241 has been obtained using activation techniques and monoenergetic γ-ray beams from the HIγS facility. The induced activity of Am240 produced via the Am241(γ,n) reaction was measured in the energy interval from 9 to 16 MeV utilizing high-resolution γ-ray spectroscopy. The experimental data for the Am241(γ,n) reaction in the giant dipole resonance energy region are compared with statistical nuclear-model calculations.
Conformation-Selective Resonant Photoelectron Spectroscopy via Dipole-Bound States of Cold Anions.
Huang, Dao-Ling; Liu, Hong-Tao; Ning, Chuan-Gang; Wang, Lai-Sheng
2015-06-18
Molecular conformation is important in chemistry and biochemistry. Conformers connected by low energy barriers can only be observed at low temperatures and are difficult to be separated. Here we report a new method to obtain conformation-selective spectroscopic information about dipolar molecular radicals via dipole-bound excited states of the corresponding anions cooled in a cryogenic ion trap. We observed two conformers of cold 3-hydroxyphenoxide anions [m-HO(C6H4)O(-)] in high-resolution photoelectron spectroscopy and measured different electron affinities, 18,850(8) and 18,917(5) cm(-1), for the syn and anti 3-hydroxyphenoxy radicals, respectively. We also observed dipole-bound excited states for m-HO(C6H4)O(-) with different binding energies for the two conformers due to the different dipole moments of the corresponding 3-hydroxyphenoxy radicals. Excitations to selected vibrational levels of the dipole-bound states result in conformation-selective photoelectron spectra. This method should be applicable to conformation-selective spectroscopic studies of any anions with dipolar neutral cores.
Analysis of common-mode resonances in arrays of connected dipoles and possible solutions
Cavallo, D.; Neto, A.; Gerini, G.
2009-01-01
A prototype array of dual polarized connected dipoles has been manufactured. The feed structure is composed by two orthogonal 8x8 elements for each polarization (128). The operational frequency ranges from 6 to 9 GHz (40% relative bandwidth). Preliminary measurements highlighted the presence of unpr
Lemeshko, Mikhail
2011-01-01
We show that the electric dipole-dipole interaction between a pair of polar molecules undergoes an all-out transformation when superimposed by a far-off resonant optical field. The combined interaction potential becomes tunable by variation of wavelength, polarization and intensity of the optical field and its dependence on the intermolecular separation exhibits a crossover from an inverse-power to an oscillating behavior. The ability thereby offered to control molecular interactions opens up avenues toward the creation and manipulation of novel phases of ultracold polar gases among whose characteristics is a long-range entanglement of the dipoles' mutual orientation. We devised an accurate analytic model of such optical-field-dressed dipole-dipole interaction potentials, which enables a straightforward access to the optical-field parameters required for the design of intermolecular interactions in the laboratory.
Tichit, Paul-Henri; Burokur, Shah Nawaz; Qiu, Cheng-Wei; de Lustrac, André
2013-09-01
It has long been conjectured that isotropic radiation by a simple coherent source is impossible due to changes in polarization. Though hypothetical, the isotropic source is usually taken as the reference for determining a radiator’s gain and directivity. Here, we demonstrate both theoretically and experimentally that an isotropic radiator can be made of a simple and finite source surrounded by electric-field-driven LC resonator metamaterials designed by space manipulation. As a proof-of-concept demonstration, we show the first isotropic source with omnidirectional radiation from a dipole source (applicable to all distributed sources), which can open up several possibilities in axion electrodynamics, optical illusion, novel transformation-optic devices, wireless communication, and antenna engineering. Owing to the electric- field-driven LC resonator realization scheme, this principle can be readily applied to higher frequency regimes where magnetism is usually not present.
Haiwei, Mu; Jingwei, Lv; Zhaoting, Liu; Lin, Yang; Qiang, Liu; Chao, Liu [Northeast Petroleum University, School of Electronics Science, Daqing (China); Shijie, Zheng [Harbin Institute of Technology, School of Civil Engineering, Harbin (China); Tao, Sun [Agency for Science, Technology and Research (A-STAR), Institute of Microelectronics, Singapore (Singapore)
2016-04-15
Optical properties of localized surface plasmon resonances (LSPR) of Ag/ITO sliced nanosphere have been studied using discrete dipole approximation and plasmon hybridization theory. It is found that different morphologies of sliced nanosphere can induce distinctive features in the extinction spectra. In the meanwhile, gap distances and refractive index of the surrounding medium could modulate the plasmon hybridization and the LSPR shifting. At large separation, the shift of LSPR peaks for the nanosphere sliced in halves consisting of ITO and Ag is small and insensitive to the gap distance in the weak coupling, whereas smaller separation exhibits a distinct red shift. Additionally, multiple resonance peaks are excited for the nanosphere sliced in quarters consisting of ITO and Ag. In this situation, electric field is mainly distributed in the gap region of sliced nanosphere and the central point. These results indicate that different morphologies of sliced nanosphere could create abundant tunable LSPR modes, which provides potential for multiplex optical sensing. (orig.)
Arslanagic, Samel; Ziolkowski, Richard W.
2010-01-01
The present work investigates the optical properties of active coated spherical nano-particles excited by an arbitrarily located electric Hertzian dipole. The nano-particles are made of specific dielectric and plasmonic materials. The spatial near-field distribution as well as the normalized...... radiation resistance is examined. Both enhanced as well as reduced radiation effects are demonstrated. In particular, it is shown that specific active coated nano-particles can be designed to be resonant, leading to much larger values of the normalized radiation resistance than is the case...... with the corresponding passive coated nano-particles, thereby overcoming the intrinsic losses present in the plasmonic materials. Moreover, it is shown that other active coated nano-particle designs can significantly reduce the normalized radiation resistance; thus both the resonant as well as non...
Mineev, V. P.
2009-01-01
The roton excitation in the superfluid He-4 does not possess a stationary dipole moment. However, a roton has an instantaneous dipole moment, such that at any given moment one can find it in the state either with positive or with negative dipole moment projection on its momentum direction. The instantaneous value of electric dipole moment of roton excitation is evaluated. The result is in reasonable agreement with recent experimental observation of the splitting of microwave resonance absorpt...
The Higgs boson resonance width from a chiral Higgs-Yukawa model on the lattice
Gerhold, Philipp; Jansen, Karl; Kallarackal, Jim
2012-04-01
The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for quarks, leptons and the weak gauge bosons. We use a 4-dimensional Euclidean lattice formulation of the Higgs-Yukawa sector of the electroweak model to compute physical quantities in the path integral approach which is evaluated by means of Monte Carlo simulations thus allowing for fully non-perturbative calculations. The chiral symmetry of the model is incorporated by using the Neuberger overlap Dirac operator. The here considered Higgs-Yukawa model does not involve the weak gauge bosons and furthermore, only a degenerate doublet of top- and bottom quarks are incorporated. The goal of this work is to study the resonance properties of the Higgs boson and its sensitivity to the strength of the quartic self-coupling.
The Higgs boson resonance width from a chiral Higgs-Yukawa model on the lattice
Gerhold, Philipp [NIC, DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Humboldt-Universitaet zu Berlin, Institut fuer Physik, Newtonstr. 15, D-12489 Berlin (Germany); Jansen, Karl, E-mail: Karl.Jansen@desy.de [NIC, DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Kallarackal, Jim [NIC, DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Humboldt-Universitaet zu Berlin, Institut fuer Physik, Newtonstr. 15, D-12489 Berlin (Germany)
2012-04-20
The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for quarks, leptons and the weak gauge bosons. We use a 4-dimensional Euclidean lattice formulation of the Higgs-Yukawa sector of the electroweak model to compute physical quantities in the path integral approach which is evaluated by means of Monte Carlo simulations thus allowing for fully non-perturbative calculations. The chiral symmetry of the model is incorporated by using the Neuberger overlap Dirac operator. The here considered Higgs-Yukawa model does not involve the weak gauge bosons and furthermore, only a degenerate doublet of top- and bottom quarks are incorporated. The goal of this work is to study the resonance properties of the Higgs boson and its sensitivity to the strength of the quartic self-coupling.
The Higgs boson resonance width from a chiral Higgs-Yukawa model on the lattice
Gerhold, Philipp; Kallarackal, Jim [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2011-11-15
The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for quarks, leptons and the weak gauge bosons. We use a 4-dimensional Euclidean lattice formulation of the Higgs-Yukawa sector of the electroweak model to compute physical quantities in the path integral approach which is evaluated by means of Monte Carlo simulations thus allowing for fully non perturbative calculations. The chiral symmetry of the model is incorporated by using the Neuberger overlap Dirac operator. The here considered Higgs-Yukawa model does not involve the weak gauge bosons and furthermore, only a degenerate doublet of top- and bottom quarks are incorporated. The goal of this work is to study the resonance properties of the Higgs boson and its sensitivity to the strength of the quartic self coupling. (orig.)
The Higgs boson resonance width from a chiral Higgs-Yukawa model on the lattice
Gerhold, Philipp; Kallarackal, Jim
2011-01-01
The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for quarks, leptons and the weak gauge bosons. We use a 4-dimensional Euclidean lattice formulation of the Higgs-Yukawa sector of the electroweak model to compute physical quantities in the path integral approach which is evaluated by means of Monte Carlo simulations thus allowing for fully non perturbative calculations. The chiral symmetry of the model is incorporated by using the Neuberger overlap Dirac operator. The here considered Higgs-Yukawa model does not involve the weak gauge bosons and furthermore, only a degenerate doublet of top- and bottom quarks are incorporated. The goal of this work is to study the resonance properties of the Higgs boson and its sensitivity to the strength of the quartic self coupling.
Giant peak to valley ratio in a GaN based resonant tunnel diode with barrier width modulation
Sankaranarayanan, Sandeep; Saha, Dipankar
2016-10-01
A barrier width modulated GaN based resonant tunnel diode is theoretically proposed which exhibits a giant peak to valley current ratio as high as 60 and a high negative differential conductance (NDC) of 1.77 × 106 S/cm2 with very low valley current density of 3 mA/cm2. This is achieved by the unique characteristic of the device current which monotonically decreases for applied voltages greater than the valley voltage in our simulation window. This is in contrast to all the other negative differential conductance based devices which experience an immediate exponential increase in current after the NDC region. The proposed device is also the first bidirectional tunneling diode which shows negative differential conductance for both polarity of the applied bias which is normally not observed with the conventional GaN/AlGaN double barrier structures due to the strong asymmetry arising from the internal electric fields due to polarization. The unique characteristics of the device can be attributed to the use of a modulated barrier width which is made possible by a polarization modulating InGaN layer and efficient utilization of internal electric fields in III-nitrides.
Papp, P., E-mail: papp@fmph.uniba.sk [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina, 84248 Bratislava (Slovakia); Matejčík, Š. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina, 84248 Bratislava (Slovakia); Mach, P.; Urban, J. [Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina, 84248 Bratislava (Slovakia); Paidarová, I. [J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Dolejškova 3, CZ-182 23 Praha 8 (Czech Republic); Horáček, J., E-mail: horacek@mbox.troja.mff.cuni.cz [Charles University, Faculty of Mathematics and Physics, V Holešovičkách 2, CZ-180 00 Praha 8 (Czech Republic)
2013-06-03
Highlights: • The anions are stabilized by additional charges on the nuclei. • The energy dependence of anions and neutrals on nuclear charges are calculated by ab initio methods. • Resonance energies and widths are obtained from the energy data by analytical continuation with Padé approximation. • The resonance energies and widths of amino acids are compared with Nestmann–Peyerimhoff’s method and with experiment. • The resonance energies and (widths) of formic acid monomer and dimer are 2.09 (0.33) eV and 1.7 (0.13) eV, respectively. - Abstract: The method of analytic continuation in the coupling constant (ACCC) in combination with use of the statistical Padé approximation is applied to the determination of resonance energy and width of some amino acids and formic acid dimer. Standard quantum chemistry codes provide accurate data which can be used for analytic continuation in the coupling constant to obtain the resonance energy and width of organic molecules with a good accuracy. The obtained results are compared with the existing experimental ones.
A Resonant Scanning Dipole-Antenna Probe for Enhanced Nanoscale Imaging
Neumann, L.; Oever, van 't J.J.F.; Hulst, van N.F.
2013-01-01
We present a scanning antenna probe that provides 35 nm optical hotspots with a 16-fold excitation enhancement. A resonant optical antenna, tuned to operation in the visible, is carved into the aluminum-coated scanning probe. The antenna resonances, field localization, excitation, and polarization r
Francisco Torrens
2009-03-01
Full Text Available The Silberstein model of the molecular polarizability of diatomic molecules, generalized by Applequist et al. for polyatomic molecules, is analyzed. The atoms are regarded as isotropically polarizable points located at their nuclei, interacting via the fields of their induced dipoles. The use of additive values for atom polarizabilities gives poor results, in some cases leading to artificial predictions of absorption bands. The molecular polarizability of methane and its derivative are computed. The agreement with experimental mean molecular polarizabilities is within 1–5%. A hypothesis is indispensable for a suitable representation of polarizability derivative.
Zobov, V. E., E-mail: rsa@iph.krasn.ru [Russian Academy of Sciences, Kirenskii Institute of Physics, Siberian Branch (Russian Federation); Kucherov, M. M. [Siberian Federal University, Institute of Space and Information Technologies (Russian Federation)
2017-01-15
The singularities of the time autocorrelation functions (ACFs) of magnetically diluted spin systems with dipole–dipole interaction (DDI), which determine the high-frequency asymptotics of autocorrelation functions and the wings of a magnetic resonance line, are studied. Using the self-consistent fluctuating local field approximation, nonlinear equations are derived for autocorrelation functions averaged over the independent random arrangement of spins (magnetic atoms) in a diamagnetic lattice with different spin concentrations. The equations take into account the specificity of the dipole–dipole interaction. First, due to its axial symmetry in a strong static magnetic field, the autocorrelation functions of longitudinal and transverse spin components are described by different equations. Second, the long-range type of the dipole–dipole interaction is taken into account by separating contributions into the local field from distant and near spins. The recurrent equations are obtained for the expansion coefficients of autocorrelation functions in power series in time. From them, the numerical value of the coordinate of the nearest singularity of the autocorrelation function is found on the imaginary time axis, which is equal to the radius of convergence of these expansions. It is shown that in the strong dilution case, the logarithmic concentration dependence of the coordinate of the singularity is observed, which is caused by the presence of a cluster of near spins whose fraction is small but contribution to the modulation frequency is large. As an example a silicon crystal with different {sup 29}Si concentrations in magnetic fields directed along three crystallographic axes is considered.
Madrid, Rafael de la, E-mail: rafael.delamadrid@lamar.edu
2017-06-15
We express the resonant energies of the delta-shell potential in terms of the Lambert W function, and we calculate their decay widths and decay constants. The ensuing numerical results strengthen the interpretation of such decay widths and constants as a way to quantify the coupling between a resonance and the continuum. We calculate explicitly the decay energy spectrum of the resonances of the delta-shell potential, and we show numerically that the lineshape of such spectrum is not the same as, and can be very different from, the Breit–Wigner (Lorentzian) distribution. We argue that the standard Golden Rule cannot describe the interference of two resonances, and we show how to describe such interference by way of the decay energy spectrum of two resonant states.
A resonant scanning dipole-antenna probe for enhanced nanoscale imaging.
Neumann, Lars; van 't Oever, Jorick; van Hulst, Niek F
2013-11-13
We present a scanning antenna probe that provides 35 nm optical hotspots with a 16-fold excitation enhancement. A resonant optical antenna, tuned to operation in the visible, is carved into the aluminum-coated scanning probe. The antenna resonances, field localization, excitation, and polarization response are probed in the near-field by scanning over single fluorescent nanobeads. At the same time, the distance-dependent coupling of the emission to the antenna mode is mapped. Good agreement with theory is obtained. The presented scanning antenna approach is useful for both nanoscale plasmonic mode imaging and (bio)imaging.
Liu, Yang; Hsu, Yung; Hsu, Chin-Wei; Yang, Ling-Gang; Chow, Chi-Wai; Yeh, Chien-Hung; Lai, Yin-Chieh; Tsang, Hon-Ki
2016-02-01
In this work, we propose and demonstrate a stable single-longitudinal-mode (SLM) fiber laser with narrow line-width by using an integrated silicon-on-insulator micro-ring resonator (SOI MRR) and two subsidiary fiber rings for the first time, to the best of our knowledge. The laser is tunable over the wavelength range from 1546 to 1570 nm, with only step tuning of 2 nm steps. A maximum 49 dB side mode suppression ratio (SMSR) can be achieved. The compact SOI MRR provides a large free-spectral-range (FSR), while the subsidiary rings provide Vernier effect producing a single lasing mode. The FSR of the SOI MRR can be very large and controllable (since it is easy to fabricate small SOI MRR when compared with making small fiber-rings) using the complementary-metal-oxide-semiconductor (CMOS) compactable SOI fabrication processes. In our proposed laser, the measured single sideband (SSB) spectrum shows that the densely spaced longitudinal modes can be significantly suppressed to achieve SLM. The laser linewidth is only 3.5 kHz measured by using the self-heterodyne method. 30 min stability evaluation in terms of lasing wavelength and optical power is performed; showing the optical wavelength and power are both very stable, with fluctuations of only 0.02 nm and 0.8 dB, respectively.
Double helix dipole design applied to magnetic resonance: a novel NMR coil.
Alonso, J; Soleilhavoup, A; Wong, A; Guiga, A; Sakellariou, D
2013-10-01
A new radio frequency coil design for NMR experiments is presented. The coil generates a magnetic field purely perpendicular to the longitudinal axis of the main magnet, and its sensitivity is higher than the traditional transversal resonators. This is achieved by adding the contribution of two tilted solenoid coils fed with opposite currents. The work presents the mathematical model for the new coil, numerical simulations performed to validate that model and a comparison with an equivalent saddle coil. The new design is tested experimentally in low- and high-field NMR experiments and compared with results obtained with equivalent saddle coils. The results lead to conclude that the new design provides better sensitivity than the transverse resonators commonly used in NMR. Copyright © 2013 Elsevier Inc. All rights reserved.
THE ANGULAR-MOMENTUM DEPENDENCE OF THE GIANT-DIPOLE RESONANCE IN DY-154
NOORMAN, RF; BACELAR, JC; HARAKEH, MN; HESSELINK, WHA; HOFMANN, HJ; Kalantar-Nayestanaki, Nasser; VANSCHAGEN, JPS; STOLK, A; SUJKOWSKI, Z; DEVOIGT, MJA; VANDERWOUDE, A
1994-01-01
The statistical gamma-ray decay of the compound nucleus 154Dy* formed at an excitation energy of 69 MeV is studied in three angular-momentum windows [J] = 31,42 and 50h. The GDR strength function extracted from the data indicates a constant centroid energy for the resonance E(GDR) = 15.2 +/- 0.5 MeV
A Broadband Dipolar Resonance in THz Metamaterials
Sangala, Bagvanth Reddy; Gopal, Achanta Venu; Prabhu, S S
2014-01-01
We demonstrate a THz metamaterial with broadband dipole resonance originating due to the hybridization of LC resonances. The structure optimized by finite element method simulations is fabricated by electron beam lithography and characterized by terahertz time-domain spectroscopy. Numerically, we found that when two LC metamaterial resonators are brought together, an electric dipole resonance arises in addition to the LC resonances. We observed a strong dependence of the width of these resonances on the separation between the resonators. This dependence can be explained based on series and parallel RLC circuit analogies. The broadband dipole resonance appears when both the resonators are fused together. The metamaterial has a stopband with FWHM of 0.47 THz centered at 1.12 THz. The experimentally measured band features are in reasonable agreement with the simulated ones. The experimental power extinction ratio of THz in the stopbands is found to be 15 dB.
Cao, L G; Colo', G; Sagawa, H
2015-01-01
We investigate the impact of the neutron-skin thickness Delta(R) on the energy difference between the anti-analog giant dipole resonance (AGDR), E(AGDR), and the isobaric analog state (IAS), E(IAS), in a heavy nucleus such as 208Pb. For guidance, we first develop a simple and analytic, yet physical, approach based on the Droplet Model that linearly connects the energy difference E(AGDR)-E(IAS) with Delta(R). To test this correlation on more fundamental grounds, we employ a family of systematically varied Skyrme energy density functionals where variations on the value of the symmetry energy at saturation density J are explored. The calculations have been performed within the fully self consistent Hartree-Fock (HF) plus charge-exchange random phase approximation (RPA) framework. We confirm the linear correlation within our microscopic apporach and, by comparing our results with available experimental data in 208Pb, we find that our analysis is consistent with Delta(R) = 0.204 \\pm 0.009 fm, J = 31.4 \\pm 0.5 MeV ...
Thiep, Tran Duc; An, Truong Thi; Cuong, Phan Viet; Vinh, Nguyen The; Hue, Bui Minh; Belov, A. G.; Maslov, O. D.; Mishinsky, G. V.; Zhemenik, V. I.
2017-01-01
We have determined the isomeric ratios of isomeric pairs 97m,gNb, 95m,gNb and 91m,gMo produced in 98Mo(γ, p)97m,gNb, 96Mo(γ, p)95m,gNb and 92Mo(γ, n)91m,gMo photonuclear reactions in the giant dipole resonance (GDR) region by the activation method. The results were analyzed, discussed and compared with the similar data from literature to examine the role of excitation energy, neutron configuration, channel effect and direct and pre-equilibrium processes in (γ, p) photonuclear reactions. In this work the isomeric ratios for 97m,gNb from 14 to 19 MeV, for 195m,gNb from14 to 24 MeV except 20 and 23.5 MeV and for 91m,gMo at 14 and 15 MeV are the first time measurements.
Study of the pygmy dipole resonance in {sup 94}Mo using the (α,α{sup ′}γ) coincidence technique
Derya, V., E-mail: derya@ikp.uni-koeln.de [Institut für Kernphysik, Universität zu Köln, Zülpicher Straße 77, 50937 Köln (Germany); Endres, J.; Elvers, M. [Institut für Kernphysik, Universität zu Köln, Zülpicher Straße 77, 50937 Köln (Germany); Harakeh, M.N. [Kernfysisch Versneller Instituut, Rijksuniversiteit Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); Pietralla, N.; Romig, C. [Institut für Kernphysik, TU Darmstadt, Schlossgartenstraße 9, 64289 Darmstadt (Germany); Savran, D. [ExtreMe Matter Institute EMMI and Research Division, GSI, Planckstraße 1, 64291 Darmstadt (Germany); Frankfurt Institute for Advanced Studies FIAS, Ruth-Moufang-Straße 1, 60438 Frankfurt am Main (Germany); Scheck, M.; Siebenhühner, F. [Institut für Kernphysik, TU Darmstadt, Schlossgartenstraße 9, 64289 Darmstadt (Germany); Stoica, V.I. [Kernfysisch Versneller Instituut, Rijksuniversiteit Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); Department of Sociology/ICS, Rijksuniversiteit Groningen, Grote Rozenstraat 31, 9712 TG Groningen (Netherlands); Wörtche, H.J. [Kernfysisch Versneller Instituut, Rijksuniversiteit Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); and others
2013-05-15
The (α,α{sup ′}γ) reaction at E{sub α}=136 MeV was used to study the electric dipole response in the open-shell vibrational nucleus {sup 94}Mo below the neutron-separation threshold. The coincidence experiment has been performed at the Kernfysisch Versneller Instituut in Groningen, The Netherlands, exploiting the Big-Bite Spectrometer and an array of large volume High-Purity Germanium (HPGe) detectors. Due to the excellent energy resolution and high selectivity to transitions stemming from the pygmy dipole resonance, singles α-scattering cross sections could be determined for individual electric dipole excitations between 4 and 8 MeV. For three of the excited low-lying J{sup π}=1{sup −} states in {sup 94}Mo a γ-decay branch into the J{sup π}=2{sub 1}{sup +} state could be observed. The experiment extends the systematic studies of the pygmy dipole resonance by real-photon scattering (γ,γ{sup ′}) experiments and (α,α{sup ′}γ) experiments. Recently, a (γ,γ{sup ′}) experiment on {sup 94}Mo was performed at the Darmstadt High-Intensity Photon Setup at the S-DALINAC in Darmstadt, Germany, permitting the comparison of B(E1)↑ strength distribution and α-scattering cross sections.
Iwamoto, C.; Utsunomiya, H.; Tamii, A.; Akimune, H.; Nakada, H.; Shima, T.; Yamagata, T.; Kawabata, T.; Fujita, Y.; Matsubara, H.; Shimbara, Y.; Nagashima, M.; Suzuki, T.; Fujita, H.; Sakuda, M.; Mori, T.; Izumi, T.; Okamoto, A.; Kondo, T.; Bilgier, B.; Kozer, H. C.; Lui, Y.-W.; Hatanaka, K.
2012-06-01
A high-resolution measurement of inelastic proton scattering off Zr90 near 0° was performed at 295 MeV with a focus on a pronounced strength previously reported in the low-energy tail of giant dipole resonance. A forest of fine structure was observed in the excitation energy region 7-12 MeV. A multipole decomposition analysis of the angular distribution for the forest was carried out using the ECIS95 distorted-wave Born approximation code with the Hartree-Fock plus random-phase approximation model of E1 and M1 transition densities and inclusion of E1 Coulomb excitation. The analysis separated pygmy dipole and M1 resonances in the forest at EPDR=9.15±0.18MeV with ΓPDR=2.91±0.64MeV and at EM1=9.53±0.06MeV with ΓM1=2.70±0.17MeV in the Lorentzian function, respectively. The B(E1)↑ value for pygmy dipole resonance over 7-11 MeV is 0.75±0.08e2fm2, which corresponds to 2.1±0.2% of the Thomas-Reiche-Kuhn sum rule.
Iwaszczuk, Krzysztof; Zalkovskij, Maksim; Strikwerda, Andrew
We experimentally show that metallic dipole antennas emit ultraviolet radiation when illuminated with ultrashort high-power terahertz pulses due to ultrafast electronfield emission from the metal and consecutive ionization and excitation of atmospheric gas molecules.......We experimentally show that metallic dipole antennas emit ultraviolet radiation when illuminated with ultrashort high-power terahertz pulses due to ultrafast electronfield emission from the metal and consecutive ionization and excitation of atmospheric gas molecules....
Chugunov, Yu. V.; Shirokov, E. A.
2016-05-01
The paper discusses issues related to the radiation and reception of quasi-electrostatic waves by short antennas in resonance conditions (in the whistler range) in magnetized plasma. First, the response of the receiving antenna on the incident field of slow quasipotential waves is analyzed. It made it possible to explain in detail the results of the two-point rocket experiment OEDIPUS-C in the Earth's ionosphere. Second, the problem of the charge distribution along the short transmission (reception) dipole antenna is considered. The corresponding integral equation is obtained and solved analytically. The impedance of the antenna is found. It is shown that in the majority of cases, charge distribution along the dipole length can be considered constant.
Kotulla, M; Annand, J R M; Beck, R; Caselotti, G; Fog, L S; Hornidge, D; Janssen, S; Krusche, B; McGeorge, J C; McGregor, I J D; Mengel, K; Messchendorp, J G; Metag, V; Novotny, R; Pfeiffer, M; Rost, M; Sack, S; Sanderson, R; Schadmand, S; Watts, D P
2002-01-01
The reaction $\\gamma p \\to \\pi^\\circ \\gamma^\\prime p$ has been measured with the TAPS calorimeter at the Mainz Microtron accelerator facility MAMI for energies between $\\sqrt{s}$ = 1221--1331 MeV. Cross sections differential in angle and energy have been determined for all particles in the final state in three bins of the excitation energy. This reaction channel provides access to the magnetic dipole moment of the $\\Delta^{+}(1232)$ resonance and, for the first time, a value of $\\mu_{\\Delta^+} = (2.7_{-1.3}^{+1.0}(stat.) \\pm 1.5 (syst.) \\pm 3(theo.)) \\mu_N$ has been extracted.
Bodrov, I.V.; Davydov, M.G.; Rakhmanov, I.B. [Rostov State Univ., Rostov-na-Donu (Russian Federation)] [and others
1994-08-01
The isomeric yield ratios Y{sub m}/Y{sub g} of the {sup 90}Zr({gamma},n){sup 88m,g}Zr reaction are measured in the energy range from 13 to 21 MeV with a step of 0.5 MeV. The experimental isomeric ratios are compared with the data obtained by other authors and with the results of theoretical calculations based on the statistical theory and on the model of {open_quotes}semidirect{close_quotes} decay of the giant dipole resonance. 30 refs., 1 fig., 2 tabs.
Huynh, V.D. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1965-06-01
Radiative capture experiments by neutron time-of-flight methods have been made for following studies: distribution of partial radiative widths, effects of correlation between different radiative transitions, fluctuations of total radiative widths {gamma}{sub {gamma}} from resonance to resonance, variation of {gamma}{sub {gamma}} with number of mass and the search for the existence of potential capture. Also, some other experiments with the use of neutron capture gamma-rays spectra have been investigated. (author) [French] Par la capture des neutrons de resonance dont les energies sont selectionnees a l'aide de la technique du temps de vol, differents types d'experiences ont ete realisees concernant les etudes des distributions des largeurs radiatives partielles, des effets de correlation entre differentes voies de desexcitation, de la fluctuation des largeurs radiatives totales {gamma}{sub {gamma}} de resonance a resonance, de la variation de la quantite {gamma}{sub {gamma}} en fonction du nombre de masse et de la mise en evidence de l'existence du processus de capture potentielle. Quelques autres applications de l'emploi du spectre de rayons gamma ont egalement ete presentees. (auteur)
Miyamoto, R.; Kopp, S.E.; /Texas U.; Jansson, A.; Syphers, M.J.; /Fermilab
2007-06-01
The AC dipole is an oscillating dipole magnet which can induce large amplitude oscillations without the emittance growth and decoherence. These properties make it a good tool to measure optics of a hadron synchrotron. The vertical AC dipole for the Tevatron is powered by an inexpensive high power audio amplifier since its operating frequency is approximately 20 kHz. The magnet is incorporated into a parallel resonant system to maximize the current. The use of a vertical pinger magnet which has been installed in the Tevatron made the cost relatively inexpensive. Recently, the initial system was upgraded with a more powerful amplifier and oscillation amplitudes up to 2-3{sigma} were achieved with the 980 GeV proton beam. This paper discusses details of the Tevatron AC dipole system and also shows its test results.
Peric, Mirna; Bales, Barney L; Peric, Miroslav
2012-03-22
The work in part 6 of this series (J. Phys. Chem. A 2009, 113, 4930), addressing the task of separating the effects of Heisenberg spin exchange (HSE) and dipole-dipole interactions (DD) on electron paramagnetic resonance (EPR) spectra of nitroxide spin probes in solution, is extended experimentally and theoretically. Comprehensive measurements of perdeuterated 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl (pDT) in squalane, a viscous alkane, paying special attention to lower temperatures and lower concentrations, were carried out in an attempt to focus on DD, the lesser understood of the two interactions. Theoretically, the analysis has been extended to include the recent comprehensive treatment by Salikhov (Appl. Magn. Reson. 2010, 38, 237). In dilute solutions, both interactions (1) introduce a dispersion component, (2) broaden the lines, and (3) shift the lines. DD introduces a dispersion component proportional to the concentration and of opposite sign to that of HSE. Equations relating the EPR spectral parameters to the rate constants due to HSE and DD have been derived. By employing nonlinear least-squares fitting of theoretical spectra to a simple analytical function and the proposed equations, the contributions of the two interactions to items 1-3 may be quantified and compared with the same parameters obtained by fitting experimental spectra. This comparison supports the theory in its broad predictions; however, at low temperatures, the DD contribution to the experimental dispersion amplitude does not increase linearly with concentration. We are unable to deduce whether this discrepancy is due to inadequate analysis of the experimental data or an incomplete theory. A new key aspect of the more comprehensive theory is that there is enough information in the experimental spectra to find items 1-3 due to both interactions; however, in principle, appeal must be made to a model of molecular diffusion to separate the two. The permanent diffusion model is used to
Yang, Fan; Voelkel, Jacob E; Dearden, David V
2012-06-01
We demonstrate a technique for determining molecular collision cross sections via measuring the variation of Fourier transform ion cyclotron resonance (FTICR) line width with background damping gas pressure, under conditions where the length of the FTICR transient is pressure limited. Key features of our method include monoisotopic isolation of ions, the pulsed introduction of damping gas to a constant pressure using a pulsed leak valve, short excitation events to minimize collisions during the excitation, and proper choice of damping gas (Xe is superior to He). The measurements are reproducible within a few percent, which is sufficient for distinguishing between many structural possibilities and is comparable to the uncertainty in cross sections calculated from computed molecular structures. These techniques complement drift ion mobility measurements obtained on dedicated instruments. They do not require a specialized instrument, but should be easily performed on any FTICR mass spectrometer equipped with a pulsed leak valve.
Dixit, Karuna; Pande, Ajay; Pande, Jayanti; Sarma, Siddhartha P
2016-06-07
A hallmark of the crystallin proteins is their exceptionally high solubility, which is vital for maintaining the high refractive index of the eye lens. Human γC-crystallin is a major γ-crystallin whose mutant forms are associated with congenital cataracts but whose three-dimensional structure is not known. An earlier study of a homology model concluded that human γC-crystallin has low intrinsic solubility, mainly because of the atypical magnitude and fluctuations of its dipole moment. On the contrary, the high-resolution tertiary structure of human γC-crystallin determined here shows unequivocally that it is a highly soluble, monomeric molecule in solution. Notable differences between the orientations and interactions of several side chains are observed upon comparison to those in the model. No evidence of the pivotal role ascribed to the effect of dipole moment on protein solubility was found. The nuclear magnetic resonance structure should facilitate a comprehensive understanding of the deleterious effects of cataract-associated mutations in human γC-crystallin.
Ponciano-Ojeda, Francisco; López-Hernández, Oscar; Mojica-Casique, Cristian; Colín-Rodríguez, Ricardo; Ramírez-Martínez, Fernando; Flores-Mijangos, Jesús; Sahagún, Daniel; Jáuregui, Rocío; Jiménez-Mier, José
2015-01-01
Direct evidence of excitation of the 5p3/2 -> 6p3/2 electric dipole forbidden transition in atomic rubidium is presented. The experiments were performed in a room temperature rubidium cell with continuous wave extended cavity diode lasers. Optical-optical double resonance spectroscopy with counterpropagating beams allows the detection of the non-dipole transition free of Doppler broadening. The 5p3/2 state is prepared by excitation with a laser locked to the maximum F cyclic transition of the D2 line, and the forbidden transition is produced by excitation with a 911 nm laser. Production of the forbidden transition is monitored by detection of the 420 nm fluorescence that results from decay of the 6p3/2 state. Spectra with three narrow lines (~ 13 MHz FWHM) with the characteristic F - 1, F and F + 1 splitting of the 6p3/2 hyperfine structure in both rubidium isotopes were obtained. The results are in very good agreement with a direct calculation that takes into account the 5s -> 5p3/2 preparation dynamics, the...
Spin-dipole strength functions of $^4$He with realistic nuclear forces
Horiuchi, W
2013-01-01
Both isoscalar and isovector spin-dipole excitations of $^4$He are studied using realistic nuclear forces in the complex scaling method. The ground state of $^4$He and discretized continuum states with $J^{\\pi}=0^-, 1^-, 2^-$ for A=4 nuclei are described in explicitly correlated Gaussians reinforced with global vectors for angular motion. Two- and three-body decay channels are specifically treated to take into account final state interactions. The observed resonance energies and widths of the negative-parity levels are all in fair agreement with those calculated from both the spin-dipole and electric-dipole strength functions as well as the energy eigenvalues of the complex scaled Hamiltonian. Spin-dipole sum rules, both non energy-weighted and energy-weighted, are discussed in relation to tensor correlations in the ground state of $^4$He.
Semmler, Diego; Aumann, T.; Bauer, C.; Baumann, M.; Beckstein, M.; Beller, J.; Blecher, A.; Cvejin, N.; Duchene, M.; Hug, F.; Kahlbow, J.; Knoerzer, M.; Kreis, K.; Kremer, C.; Ries, P.; Romig, C.; Scheit, H.; Schnorrenberger, L.; Symochko, D.; Walz, C. [Institut fuer Kernphysik, Darmstadt (Germany); Lefol, R. [University of Saskatchewan, Saskatoon (Canada); Loeher, B. [ExtreMe Matter Institute EMMI and Research Division, Frankfurt (Germany); Institute for Advanced Studies FIAS, Frankfurt (Germany)
2014-07-01
The low energy photon tagger NEPTUN at the S-DALINAC delivers a quasi-monoenergetic photon beam between about 4 MeV and 20 MeV with a resolution of approximately 25 keV. Tagged photons provide the possibility to measure the dipole strength of nuclei in the energy range below and above the neutron threshold. The highly efficient LaBr{sub 3} based spectrometer GALATEA will be used to detect not only the direct decays to the ground state, but also cascading decays can be measured with suitable efficiency. We will measure (γ,n)- and (γ,nγ)-reactions with neutron detectors based on plastic scintillators. This talk provides an overview about setup and goals of the NEPTUN experiment as well as the current state of the commissioning phase. Planned optimizations of the setup, based on the results of a test beam time in June 2013, are also presented.
Rita de Cássia de Oliveira Sebastião
2008-01-01
Full Text Available The relationship between the magnetic dipole-dipole potential energy function and its quantum analogue is presented in this work. It is assumed the reader is familiar with the classical expression of the dipolar interaction and has basic knowledge of the quantum mechanics of angular momentum. Except for these two points only elementary steps are involved.
Polarization-selective resonant photonic crystal photodetector
Yang, Jin-Kyu; Seo, Min-Kyo; Hwang, In-Kag; Kim, Sung-Bock; Lee, Yong-Hee
2008-11-01
Resonance-assisted photonic crystal (PhC) slab photodetectors are demonstrated by utilizing six 7-nm-thick InGaAsP quantum wells. In order to encourage efficient photon coupling into the slab from the vertical direction, a coupled-dipole-cavity-array PhC structure is employed. Inheriting the characteristics of the dipole mode, this resonant detector is highly polarization selective and shows a 22-nm-wide spectral width. The maximum responsivity of 0.28A/W, which is >20 times larger than that of the identical detector without the pattern, is observed near 1.56μm.
Ratsaby, Joel
2008-01-01
Kolmogorov argued that the concept of information exists also in problems with no underlying stochastic model (as Shannon's information representation) for instance, the information contained in an algorithm or in the genome. He introduced a combinatorial notion of entropy and information $I(x:\\sy)$ conveyed by a binary string $x$ about the unknown value of a variable $\\sy$. The current paper poses the following questions: what is the relationship between the information conveyed by $x$ about $\\sy$ to the description complexity of $x$ ? is there a notion of cost of information ? are there limits on how efficient $x$ conveys information ? To answer these questions Kolmogorov's definition is extended and a new concept termed {\\em information width} which is similar to $n$-widths in approximation theory is introduced. Information of any input source, e.g., sample-based, general side-information or a hybrid of both can be evaluated by a single common formula. An application to the space of binary functions is con...
Chen, Disheng; Lander, Gary R.; Solomon, Glenn S.; Flagg, Edward B.
2017-01-01
Resonant photoluminescence excitation (RPLE) spectra of a neutral InGaAs quantum dot show unconventional line shapes that depend on the detection polarization. We characterize this phenomenon by performing polarization-dependent RPLE measurements and simulating the measured spectra with a three-level quantum model. The spectra are explained by interference between fields coherently scattered from the two fine structure split exciton states, and the measurements enable extraction of the steady-state coherence between the two exciton states.
Silva, Clodoaldo J.; Daqaq, Mohammed F.
2017-02-01
Despite the shear amount of research studies on nonlinear flexural dynamics of cantilever beams, very few efforts address the practical geometry involving a constant thickness and linearly-varying width. This stems from the nature of the associated linear eigenvalue problem which cannot be easily solved in closed form. In this paper, we present a closed-form solution to this particular linear eigenvalue problem in the form of a general Meijer-G differential equation for which a solution is readily available in the shape of the Meijer-G functions. Using this approach, the exact linear modal frequencies and shapes are obtained and used in the discretization of the nonlinear partial-differential equation describing the dynamics of the system. The discretized system of ordinary-differential equations is then solved using the method of multiple scales to obtain an approximate analytical solution describing the primary resonance behavior of a given vibration mode. An analytical expression for the modal effective nonlinearity is obtained and used to analyze the influence of the beam's tapering on the nonlinear primary resonance behavior of the response (softening/hardening). Results are then compared to a finite element (FE) solution of the linear eigenvalue problem in which the modal shapes obtained using the FE method are fit into a set of orthogonal polynomial functions and used to discretize the nonlinear problem. It is shown that, while the modal frequencies obtained using the FE method approximate those obtained analytically with negligible error (less than 1%), there is a substantial error in the resulting estimates of the modal effective nonlinearity. This indicates that, even negligible errors in the approximate solution of the linear problem, can propagate to become significant when analyzing the nonlinear problem further reinforcing the importance of the exact solution.
Integral Measurement of Dipole Prototype of CSR
无
2001-01-01
The dipole prototype is C type used as bending magnet of the injection beam line in CSR, and acts as a model of the dipoles in the CSR main ring simultaneously. The designed relative uniformity of good field is 0.001 in 100 mm width. The results of the local distribution and transfunction at transverse profile measured
Peters, William; Grzywacz, R.; Madurga, M.; Paulauskas, S.; Taylor, S.; Allen, J.; Cizewski, J. A.; Manning, B.; Howard, M. E.; Bardayan, D. W.; Pain, S. D.; Clement, R. C. C.; Ilyushkin, S.; O'Malley, P. D.; Ikeyama, R.; Kozub, R. L.; Long, K. D.; Bergstrom, Z. J.; Deyoung, P. A.; Rogers, W. F.; Smith, J.; Jones, M.; Baumann, T.; Thoennessen, M.; Vandle; Mona Collaboration
2013-10-01
Due to the long half-life of 56Ni and the low proton threshold of 57Cu, the (p, γ) reaction on 56Ni is the linchpin reaction for heavier elements in the rp process of explosive nucleosynthesis. A new attempt to measure the proton partial width of the excited 1/2- state in 57Cu and to indirectly extract the proton-capture resonance strength was performed at the National Superconducting Cyclotron Laboratory using the Versatile Array of Neutron Detectors at Low Energy (VANDLE) along with the MoNA-LISA neutron array. The VANDLE setup of digitizing electronics was event-matched to the MoNA-LISA-Sweeper data acquisition system. After a test run with a stable 40Ca beam, a beam of 56Ni impinged onto a deuterated polyethylene target inducing (d,n) transfer reactions to predominantly single-proton states in 57Cu. These experiments were the commissioning experiments for VANDLE with a transfer reaction. Details of the unique experimental setup will be presented as well as current analysis of the data with both 40Ca and 56Ni beams. Work supported in part by the USDoE Office of Science and the National Nuclear Security Administration Stewardship Science Academic Alliance and the National Science Foundation.
WIDTHS AND AVERAGE WIDTHS OF SOBOLEV CLASSES
刘永平; 许贵桥
2003-01-01
This paper concerns the problem of the Kolmogorov n-width, the linear n-width, the Gel'fand n-width and the Bernstein n-width of Sobolev classes of the periodicmultivariate functions in the space Lp(Td) and the average Bernstein σ-width, averageKolmogorov σ-widths, the average linear σ-widths of Sobolev classes of the multivariatequantities.
Study of the Pygmy Dipole Resonance in (p,p'γ) and (d,pγ) experiments with SONIC@HORUS
Pickstone, S. G.; Derya, V.; Hennig, A.; Mayer, J.; Spieker, M.; Weinert, M.; Wilhelmy, J.; Zilges, A.
2015-05-01
Last year, the new silicon-detector array SONIC with up to 8 silicon-detector positions was installed inside the existing γ-ray spectrometer HORUS consisting of 14 HPGe detectors. The combined setup SONIC@HORUS allows for a coincident detection of γ-rays and light charged particles in the exit channel of inelastic scattering and transfer reactions. As a first physics case, the Pygmy Dipole Resonance (PDR) in 92Mo has been investigated in a (p,p'γ) experiment at Ep = 10.5 MeV. Since specific excitation energy can be chosen oﬄine in the coincidence data, the sensitivity to weak decay branchings of PDR states is increased. Additionally, a second reaction mechanism for the excitation of PDR states has been tested with the new setup. In a 119Sn(d,pγ) transfer reaction at Ed = 8.5 MeV, PDR states in 120Sn could be excited. Since this one-neutron transfer reaction is sensitive to the neutron single-particle structure, it could reveal new information on the microscopic structure of the PDR.
Study of the Pygmy Dipole Resonance in (p,p’γ and (d,pγ experiments with SONIC@HORUS
Pickstone S. G.
2015-01-01
Full Text Available Last year, the new silicon-detector array SONIC with up to 8 silicon-detector positions was installed inside the existing γ-ray spectrometer HORUS consisting of 14 HPGe detectors. The combined setup SONIC@HORUS allows for a coincident detection of γ-rays and light charged particles in the exit channel of inelastic scattering and transfer reactions. As a first physics case, the Pygmy Dipole Resonance (PDR in 92Mo has been investigated in a (p,p’γ experiment at Ep = 10.5 MeV. Since specific excitation energy can be chosen oﬄine in the coincidence data, the sensitivity to weak decay branchings of PDR states is increased. Additionally, a second reaction mechanism for the excitation of PDR states has been tested with the new setup. In a 119Sn(d,pγ transfer reaction at Ed = 8.5 MeV, PDR states in 120Sn could be excited. Since this one-neutron transfer reaction is sensitive to the neutron single-particle structure, it could reveal new information on the microscopic structure of the PDR.
Krasznahorkay, A; Csige, L; Eriksen, T K; Giacoppo, F; Görgen, A; Hagen, T W; Harakeh, M N; Julin, R; Koehler, P; Paar, N; Siem, S; Stuhl, L; Tornyi, T; Vretenar, D
2013-01-01
The 208Pb(p,ngamma p)207Pb reaction at a beam energy of 30 MeV has been used to excite the anti-analog of the giant dipole resonance (AGDR) and to measure its gamma-decay of to the isobaric analog state. The energy of the transition has also been calculated with the self-consistent relativistic random-phase approximation (RRPA), and found to be linearly correlated to the predicted value of the neutron-skin thickness (DR_pn). By comparing the theoretical results with the measured transition energy, the value of 0.190 +- 0.028 fm has been determined for DR_pn of 208Pb, in agreement with previous experimental results. The AGDR excitation energy has also been used to calculate the symmetry energy at saturation (J=32.7+- 0.6 MeV) and the slope of the symmetry energy (L=49.7 +- 4.4 MeV), resulting in more stringent constraints than most of the previous studies.
What Do s- and p-Wave Neutron Average Radiative Widths Reveal
Mughabghab, S.F.
2010-04-30
A first observation of two resonance-like structures at mass numbers 92 and 112 in the average capture widths of the p-wave neutron resonances relative to the s-wave component is interpreted in terms of a spin-orbit splitting of the 3p single-particle state into P{sub 3/2} and P{sub 1/2} components at the neutron separation energy. A third structure at about A = 124, which is not correlated with the 3p-wave neutron strength function, is possibly due to the Pygmy Dipole Resonance. Five significant results emerge from this investigation: (i) The strength of the spin-orbit potential of the optical-model is determined as 5.7 {+-} 0.5 MeV, (ii) Non-statistical effects dominate the p-wave neutron-capture in the mass region A = 85 - 130, (iii) The background magnitude of the p-wave average capture-width relative to that of the s-wave is determined as 0.50 {+-} 0.05, which is accounted for quantitatively in tenns of the generalized Fermi liquid model of Mughabghab and Dunford, (iv) The p-wave resonances arc partially decoupled from the giant-dipole resonance (GDR), and (v) Gamma-ray transitions, enhanced over the predictions of the GDR, are observed in the {sup 90}Zr - {sup 98}Mo and Sn-Ba regions.
Trepanier, R. J.; Whitehead, M. A.
1986-02-01
The dependence of the NQR line width on the RF pulse intensity and period using a continuous steady state pulse train for polycrystalline 14N compounds shows a dependence on the asymmetry parameter η, the temperature, and the crystal structure.
Dey, Balaram; Mondal, Debasish; Pandit, Deepak; Mukhopadhyay, S.; Pal, Surajit [Variable Energy Cyclotron Centre, 1/AF-Bidhannagar, Kolkata 700064 (India); Bhattacharya, Srijit [Department of Physics, Barasat Govt. College, Barasat, N 24 Pgs, Kolkata 700124 (India); De, A. [Department of Physics, Raniganj Girls' College, Raniganj 713358 (India); Banerjee, K. [Variable Energy Cyclotron Centre, 1/AF-Bidhannagar, Kolkata 700064 (India); Dinh Dang, N. [Theoretical Nuclear Physics Laboratory, RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako city, Saitama 351-0198 (Japan); Quang Hung, N. [School of Engineering, Tan Tao University, Tan Tao University Avenue, Tan Duc Ecity, Duc Hoa, Long An Province (Viet Nam); Banerjee, S.R., E-mail: srb@vecc.gov.in [Variable Energy Cyclotron Centre, 1/AF-Bidhannagar, Kolkata 700064 (India)
2014-04-04
The influence of giant dipole resonance (GDR) induced quadrupole moment on GDR width at low temperatures is investigated experimentally by measuring GDR width systematically in the unexplored temperature range T=0.8–1.5 MeV, for the first time, in A∼100 mass region. The measured GDR widths, using alpha induced fusion reaction, for {sup 97}Tc confirm that the GDR width remains constant at the ground state value up to a critical temperature and increases sharply thereafter with increase in T. The data have been compared with the adiabatic Thermal Shape Fluctuation Model (TSFM), phenomenological Critical Temperature Fluctuation Model (CTFM) and microscopic Phonon Damping Model (PDM). Interestingly, CTFM and PDM give similar results and agree with the data, whereas the TSFM differs significantly even after incorporating the shell effects.
Dynamic Dipole-Dipole Interactions between Excitons in Quantum Dots of Different Sizes
Matsueda, Hideaki; Leosson, Kristjan; Xu, Zhangcheng
2005-01-01
Micro-photoluminescence spectra of GaAs/AlGaAs coupled quantum dots (QDs) are given, and proposed to be analyzed by our resonance dynamic dipole-dipole interaction (RDDDI) model, based on parity inheritance and exchange of virtual photons among QDs of different sizes.......Micro-photoluminescence spectra of GaAs/AlGaAs coupled quantum dots (QDs) are given, and proposed to be analyzed by our resonance dynamic dipole-dipole interaction (RDDDI) model, based on parity inheritance and exchange of virtual photons among QDs of different sizes....
Dynamic Dipole-Dipole Interactions between Excitons in Quantum Dots of Different Sizes
Matsueda, Hideaki; Leosson, Kristjan; Xu, Zhangcheng;
2005-01-01
Micro-photoluminescence spectra of GaAs/AlGaAs coupled quantum dots (QDs) are given, and proposed to be analyzed by our resonance dynamic dipole-dipole interaction (RDDDI) model, based on parity inheritance and exchange of virtual photons among QDs of different sizes.......Micro-photoluminescence spectra of GaAs/AlGaAs coupled quantum dots (QDs) are given, and proposed to be analyzed by our resonance dynamic dipole-dipole interaction (RDDDI) model, based on parity inheritance and exchange of virtual photons among QDs of different sizes....
Enhanced optical absorption and electric field resonance in diabolo metal bar optical antennas.
Pan, Zeyu; Guo, Junpeng
2013-12-30
Resonance behaviors of the fundamental resonance mode of diabolo metal bar optical antennas are investigated by using finite-difference time-domain (FDTD) numerical simulations and a dipole oscillator model. It is found that as the waist of the diabolo metal bar optical antenna is reduced, optical energy absorption cross section and near field enhancement at resonance increase significantly. Also reduction of the diabolo waist width causes red-shift of the resonant wavelengths in the spectra of absorption cross-section, scattering cross-section, and the near electric field. A dipole oscillator model including the self-inductance force is used to fit the FDTD numerical simulation results. The dipole oscillator model characterizes well the resonance behaviors of narrow waist diabolo metal bar optical antennas.
Efimov effect for three interacting bosonic dipoles.
Wang, Yujun; D'Incao, J P; Greene, Chris H
2011-06-10
Three oriented bosonic dipoles are treated by using the hyperspherical adiabatic representation, providing numerical evidence that the Efimov effect persists near a two-dipole resonance and in a system where angular momentum is not conserved. Our results further show that the Efimov features in scattering observables become universal, with a known three-body parameter; i.e., the resonance energies depend only on the two-body physics, which also has implications for the universal spectrum of the four-dipole problem. Moreover, the Efimov states should be long-lived, which is favorable for their creation and manipulation in ultracold dipolar gases. Finally, deeply bound two-dipole states are shown to be relatively stable against collisions with a third dipole, owing to the emergence of a repulsive interaction originating in the angular momentum nonconservation for this system.
Kuznetsov, Arseniy I; Fu, Yuan Hsing; Viswanathan, Vignesh; Rahmani, Mohsen; Valuckas, Vytautas; Kivshar, Yuri; Pickard, Daniel S; Lukiyanchuk, Boris
2014-01-01
We introduce a new concept of split-ball resonator and demonstrate a strong omnidirectional magnetic dipole response for both gold and silver spherical plasmonic nanoparticles with nanometer-scale cuts. Tunability of the magnetic dipole resonance throughout the visible spectral range is demonstrated by a change of the depth and width of the nanoscale cut. We realize this novel concept experimentally by employing the laser-induced transfer method to produce near-perfect spheres and helium ion beam milling to make cuts with the nanometer resolution. Due to high quality of the spherical particle shape, governed by strong surface tension forces during the laser transfer process, and the clean, straight side walls of the cut made by helium ion milling, magnetic resonance is observed at 600 nm in gold and at 565 nm in silver nanoparticles. Structuring arbitrary features on the surface of ideal spherical resonators with nanoscale dimensions provides new ways of engineering hybrid resonant modes and ultra-high near-f...
Kanada-En'yo, Yoshiko
2016-02-01
Isovector and isoscalar dipole excitations in 9Be and 10Be are investigated in the framework of antisymmetrized molecular dynamics, in which angular-momentum and parity projections are performed. In the present method, 1p-1h excitation modes built on the ground state and a large amplitude α -cluster mode are taken into account. The isovector giant dipole resonance (GDR) in E >20 MeV shows the two-peak structure, which is understood from the dipole excitation in the 2 α core part with the prolate deformation. Because of valence neutron modes against the 2 α core, low-energy E 1 resonances appear in E Thomas-Reiche-Kuhn sum rule and 10 % of the calculated energy-weighted sum. The dipole resonance at E ˜15 MeV in 10Be can be interpreted as the parity partner of the ground state having a 6He+α structure and has remarkable E 1 strength because of the coherent contribution of two valence neutrons. The isoscalar dipole strength for some low-energy resonances is significantly enhanced by the coupling with the α -cluster mode. For the E 1 strength of 9Be, the calculation overestimates the energy-weighted sum (EWS) in the low-energy (E <20 MeV) and GDR (20
Optical force on toroidal nanostructures: toroidal dipole versus renormalized electric dipole
Zhang, Xu-Lin; Lin, Zhifang; Sun, Hong-Bo; Chan, C T
2015-01-01
We study the optical forces acting on toroidal nanostructures. A great enhancement of optical force is unambiguously identified as originating from the toroidal dipole resonance based on the source-representation, where the distribution of the induced charges and currents is characterized by the three families of electric, magnetic, and toroidal multipoles. On the other hand, the resonant optical force can also be completely attributed to an electric dipole resonance in the alternative field-representation, where the electromagnetic fields in the source-free region are expressed by two sets of electric and magnetic multipole fields based on symmetry. The confusion is resolved by conceptually introducing the irreducible electric dipole, toroidal dipole, and renormalized electric dipole. We demonstrate that the optical force is a powerful tool to identify toroidal response even when its scattering intensity is dwarfed by the conventional electric and magnetic multipoles.
1s2p resonant inelastic X-ray scattering combined dipole and quadrupole analysis method
Bagger, Alexander; Haarman, Ties; Molina, Anna Puig
2017-01-01
, it is shown that only in the case of quadrupole excitations being present is additional information gained by RIXS compared with XAS. Combining this knowledge with methods to calculate the dipole contribution in XAS measurements gives scientists the opportunity to plan more effective experiments....
Dynamic dipole-dipole interactions between excitons in quantum dots of different sizes
Matsueda, Hideaki; Leosson, Kristjan; Xu, Zhangcheng;
2004-01-01
A model of the resonance dynamic dipole-dipole interaction between excitons confined in quantum dots (QDs) of different sizes at close enough distance is given in terms of parity inheritance and exchange of virtual photons. Microphotoluminescence spectra of GaAs-AlGaAs coupled QDs are proposed to...
Electric and Magnetic Dipole States in ^238U
Hammond, S. L.; Adekola, A.; Angell, C. T.; Karwowski, H. J.; Howell, C. R.; Kwan, E.; Rusev, G.; Tonchev, A. P.; Tornow, W.; Kelley, J. H.
2010-11-01
An investigation of dipole states in ^238U is important for the fundamental understanding of its structure. Precise experimental information on the distribution of M1 and E1 transitions in ^238U has been obtained using the nuclear resonance fluorescence technique at the High-Intensity γ-ray Source at the Triangle Universities Nuclear Laboratory. Using 100% linearly-polarized, monoenergetic γ-ray beams between incident energies of 2.0 - 5.5 MeV, the spin, parity, width, and γ-strength of the ground-state deexcitations were determined. These measurements will form a unique data set that can be used for comparison with theoretical models of collective excitations in heavy, deformed nuclei. The data can also provide isotope-specific signatures to search for special nuclear materials.
Eckstein, Felix; Wirth, Wolfgang; Cotofana, Sebastian [Paracelsus Medical University Salzburg and Nuremberg Austria and Chondrometrics GmbH, Institute of Anatomy, Ainring (Germany); Boudreau, Robert [University of Pittsburgh, Department of Epidemiology, Graduate School of Public Health, Pittsburgh, PA (United States); Wang, Zhijie; Hannon, Michael J. [University of Pittsburgh and Pittsburgh VAHS, Division of Rheumatology and Clinical Immunology, Pittsburgh, PA (United States); Duryea, Jeff [Brigham and Women' s Hospital, Harvard Medical School, Boston, MA (United States); Guermazi, Ali [Boston University School of Medicine and Boston Imaging Core Lab (BICL), LLC, Boston, MA (United States); Roemer, Frank [Boston University School of Medicine and Boston Imaging Core Lab (BICL), LLC, Boston, MA (United States); University of Erlangen-Nuremberg, Department of Radiology, Erlangen (Germany); Nevitt, Michael [OAI Coordinating Ctr., UCSF, San Francisco, CA (United States); John, Markus R. [Novartis Pharma AG, Basel (Switzerland); Ladel, Christoph [Merck KGaA, Darmstadt (Germany); Sharma, Leena [Northwestern University, Department of Medicine, Feinberg School of Medicine, Chicago, IL (United States); Hunter, David J. [University Sydney, Royal North Shore Hospital and Institute of Bone and Joint Research, Kolling Institute, Sydney, NSW (Australia); Kwoh, C.K. [University of Arizona, Division of Rheumatology and the University of Arizona Arthritis Center, Tucson, AZ (United States); Collaboration: OAI Investigators
2016-06-15
To evaluate whether change in fixed-location measures of radiographic joint space width (JSW) and cartilage thickness by MRI predict knee replacement. Knees replaced between 36 and 60 months' follow-up in the Osteoarthritis Initiative were each matched with one control by age, sex and radiographic status. Radiographic JSW was determined from fixed flexion radiographs and subregional femorotibial cartilage thickness from 3 T MRI. Changes between the annual visit before replacement (T{sub 0}) and 2 years before T{sub 0} (T{sub -2}) were compared using conditional logistic regression. One hundred and nineteen knees from 102 participants (55.5 % women; age 64.2 ± 8.7 [mean ± SD] years) were studied. Fixed-location JSW change at 22.5 % from medial to lateral differed more between replaced and control knees (case-control [cc] OR = 1.57; 95 % CI: 1.23-2.01) than minimum medial JSW change (ccOR = 1.38; 95 % CI: 1.11-1.71). Medial femorotibial cartilage loss displayed discrimination similar to minimum JSW, and central tibial cartilage loss similar to fixed-location JSW. Location-independent thinning and thickening scores were elevated prior to knee replacement. Discrimination of structural progression between knee pre-placement cases versus controls was stronger for fixed-location than minimum radiographic JSW. MRI displayed similar discrimination to radiography and suggested greater simultaneous cartilage thickening and loss prior to knee replacement. (orig.)
Khoury, Christopher G; Norton, Stephen J; Vo-Dinh, Tuan, E-mail: tuan.vodinh@duke.edu [Fitzpatrick Institute for Photonics and Department of Biomedical Engineering, Duke University, 101 Science Drive, Durham, NC 27708 (United States)
2010-08-06
This report compares COMSOL's finite element method (FEM) algorithm with the Mie theory for solving the electromagnetic fields in the vicinity of a silica-silver core-shell nanoparticle when excited by a radiating dipole. The novelty of this investigation lies in the excitation source of the nanoshell system: an oscillating electric dipole is frequently used as a model for both molecular scattering and molecular fluorescence; moreover, a common classical model of atomic or molecular spontaneous emission is a decaying electric dipole. The radiated power spectra were evaluated both analytically and numerically by integrating the Poynting vector around 20, 60 and 100 nm nanoshells, thereby solving the total and scattered fields generated by a dipole positioned inside the core and in the surrounding air medium, respectively. The agreement was excellent in amplitude, plasmon resonance peak position and full width at half-maximum. The FEM algorithm also generates accurate solutions of the near-field electromagnetics in the spatial domain, where the E-field behavior as a function of polar angle {theta} for a fixed observation radius was evaluated. The quasistatic approximation, which is valid for small nanoparticles, is also employed to assess its limitations relative to the Mie and FEM algorithms.
Quantum Zeno suppression of dipole-dipole forces
Wüster, Sebastian
2016-01-01
We consider inter-atomic forces due to resonant dipole-dipole interactions within a dimer of highly excited Rydberg atoms, embedded in an ultra-cold gas. These forces rely on a coherent superposition of two-atom electronic states, which is destroyed by continuous monitoring of the dimer state through a detection scheme utilizing controllable interactions with the background gas atoms. We show that this intrinsic decoherence of the molecular energy surface can gradually deteriorate a repulsive dimer state, causing a mixing of attractive and repulsive character. For sufficiently strong decoherence, a Zeno-like effect causes a complete arrest of interatomic forces. We finally show how short decohering pulses can controllably redistribute population between the different molecular energy surfaces.
Effects of dipole-dipole interaction on entanglement transfer
Guo Hong; Xiong Heng-Na
2008-01-01
A system consisting of two different atoms interacting with a two-mode vacuum, where each atom is resonant only with one cavity mode, is considered.The effects of dipole-dipole (dd) interaction between two atoms on the atom-atom entanglement and mode-mode entanglement are investigated. For a weak dd interaction, when the atoms are initially separable, the entanglement between them can be induced by the dd interaction, and the entanglement transfer between the atoms and the modes occurs efficiently; when the atoms are initially entangled, the entanglement transfer is almost not influenced by the dd interaction. However, for a strong dd interaction, it is difficult to transfer the entanglement from the atoms to the modes, but the atom-atom entanglement can be maintained when the atoms are initially entangled.
Khatri, Indu; Goyal, Arun; Diouldé Ba, Mamadou; Faye, Maurice; Sow, Malick; Sakho, Ibrahima; Singh, A. K.; Mohan, Man; Wagué, Ahmadou
2017-01-01
Resonance energies and total natural width of the 3pns 1P° and 3pnd 1P° Rydberg series of Mg-like (Z=13-26) ions are reported. Resonance energies of the Mg-like Al+ belonging to the 3pns 3P°→ 2 p63 p 1/2 0 2P and 3pns 3P°→ 2 p63 p3/2 0 3P transitions are also tabulated. The calculations are made in the framework of the Screening constant by unit nuclear charge (SCUNC) formalism. Excellent agreements between experiments at ALS and R-matrix calculations are obtained for both 3pns 1,3P° and 3pnd 1P° Rydberg series of the Mg-like Al+ ions. The present results for Mg-like Si2+, S4+, Cl5+, and Ar6+, compared with the only existing R-matrix calculations indicate lack of accuracy in the Mg-like Si2+ data obtained from noniterative formulation of the eigenchannel R-matrix method. New precise data for Mg-like P3+, K7+, Ca8+, Sc9+, Ti10+, V11+, Cr12+, Mn13+, and Fe14+ ions are presented as useful guidelines for investigators focusing their challenge on the Photoionization of Mg-like heavy charged ions in connection with their application in laboratory, astrophysics, and plasma physics.
Tonchev, A. P.; Tsoneva, N.; Bhatia, C.; Arnold, C. W.; Goriely, S.; Hammond, S. L.; Kelley, J. H.; Kwan, E.; Lenske, H.; Piekarewicz, J.; Raut, R.; Rusev, G.; Shizuma, T.; Tornow, W.
2017-10-01
A high-resolution study of the electromagnetic response of 206Pb below the neutron separation energy is performed using a (γ → ,γ‧) experiment at the HI γ → S facility. Nuclear resonance fluorescence with 100% linearly polarized photon beams is used to measure spins, parities, branching ratios, and decay widths of excited states in 206Pb from 4.9 to 8.1 MeV. The extracted ΣB (E 1) ↑ and ΣB (M 1) ↑ values for the total electric and magnetic dipole strength below the neutron separation energy are 0.9 ± 0.2 e2fm2 and 8.3 ± 2.0 μN2, respectively. These measurements are found to be in very good agreement with the predictions from an energy-density functional (EDF) plus quasiparticle phonon model (QPM). Such a detailed theoretical analysis allows to separate the pygmy dipole resonance from both the tail of the giant dipole resonance and multi-phonon excitations. Combined with earlier photonuclear experiments above the neutron separation energy, one extracts a value for the electric dipole polarizability of 206Pb of αD = 122 ± 10 mb /MeV. When compared to predictions from both the EDF+QPM and accurately calibrated relativistic EDFs, one deduces a range for the neutron-skin thickness of Rskin206 = 0.12- 0.19 fm and a corresponding range for the slope of the symmetry energy of L = 48- 60 MeV. This newly obtained information is also used to estimate the Maxwellian-averaged radiative cross section 205Pb (n , γ)206Pb at 30 keV to be σ = 130 ± 25 mb. The astrophysical impact of this measurement-on both the s-process in stellar nucleosynthesis and on the equation of state of neutron-rich matter-is discussed.
Toroidal dipole excitations in metamolecules formed by interacting plasmonic nanorods
Watson, Derek W; Ruostekoski, Janne; Fedotov, Vassili A; Zheludev, Nikolay I
2015-01-01
We show how the elusive toroidal dipole moment appears as a radiative excitation eigenmode in a metamolecule resonator that is formed by pairs of plasmonic nanorods. We analyze one such nanorod configuration - a toroidal metamolecule. We find that the radiative interactions in the toroidal metamolecule can be qualitatively represented by a theoretical model based on an electric point dipole arrangement. Both a finite-size rod model and the point dipole approximation demonstrate how the toroidal dipole moment is subradiant and difficult to excite by incident light. By means of breaking the geometric symmetry of the metamolecule, the toroidal mode can be excited by linearly polarized light and we provide simple optimization protocols for maximizing the toroidal dipole mode excitation. This opens up possibilities for simplified control and driving of metamaterial arrays consisting of toroidal dipole unit-cell resonators.
Artificial abelian gauge potentials induced by dipole-dipole interactions between Rydberg atoms
Cesa, A
2013-01-01
We analyze the influence of dipole-dipole interactions between Rydberg atoms on the generation of abelian artificial gauge potentials and fields. When two Rydberg atoms are driven by a uniform laser field, we show that the combined atom-atom and atom-field interactions give rise to new, non-uniform, artificial gauge potentials. We identify the mechanism responsible for the emergence of these gauge potentials. Analytical expressions for the latter indicate that the strongest artificial magnetic fields are reached in the regime intermediate between the dipole blockade regime and the regime in which the atoms are sufficiently far apart such that atom-light interaction dominates over atom-atom interactions. We discuss the differences and similarities of artificial gauge fields originating from resonant dipole-dipole and van der Waals interactions. We also give an estimation of experimentally attainable artificial magnetic fields resulting from this mechanism.
Quantum Calculation of Dipole Excitation in Fusion Reaction
2000-01-01
The excitation of the giant dipole resonance by fusion is studied with N/Z asymmetry in the entrance channel. the TDHF solution exhibits a strong dipole vibration which can be associated with a giant vibration along the main axis of a fluctuating prolate shape. The consequences on the gamma-ray emission from hot compound nuclei are discussed.
Finite-width plasmonic waveguides with hyperbolic multilayer cladding.
Babicheva, Viktoriia E; Shalaginov, Mikhail Y; Ishii, Satoshi; Boltasseva, Alexandra; Kildishev, Alexander V
2015-04-20
Engineering plasmonic metamaterials with anisotropic optical dispersion enables us to tailor the properties of metamaterial-based waveguides. We investigate plasmonic waveguides with dielectric cores and multilayer metal-dielectric claddings with hyperbolic dispersion. Without using any homogenization, we calculate the resonant eigenmodes of the finite-width cladding layers, and find agreement with the resonant features in the dispersion of the cladded waveguides. We show that at the resonant widths, the propagating modes of the waveguides are coupled to the cladding eigenmodes and hence, are strongly absorbed. By avoiding the resonant widths in the design of the actual waveguides, the strong absorption can be eliminated.
Aubert, B; Bóna, M; Boutigny, D; Couderc, F; Karyotakis, Yu; Lees, J P; Poireau, V; Tisserand, V; Zghiche, A; Graugès-Pous, E; Palano, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Battaglia, M; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Gill, M S; Groysman, Y; Jacobsen, R G; Kadyk, J A; Kerth, L T; Kolomensky, Y G; Kukartsev, G; Lynch, G; Mir, L M; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Wenzel, W A; Del Amo-Sánchez, P; Barrett, M; Ford, K E; Hart, A J; Harrison, T J; Hawkes, C M; Morgan, S E; Watson, A T; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schröder, T; Steinke, M; Boyd, J T; Burke, J P; Cottingham, W N; Walker, D; Asgeirsson, D J; Çuhadar-Dönszelmann, T; Fulsom, B G; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Khan, A; Kyberd, P; Saleem, M; Sherwood, D J; Teodorescu, L; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Onuchin, A P; Serednyakov, S I; Skovpen, Y I; Solodov, E P; Todyshev, K Y; Best, D S; Bondioli, M; Bruinsma, M; Chao, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M A; Mommsen, R K; Röthel, W; Stoker, D P; Abachi, S; Buchanan, C; Foulkes, S D; Gary, J W; Long, O; Shen, B C; Wang, K; Zhang, L; Hadavand, H K; Hill, E J; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Kovalskyi, D; Richman, J D; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Nesom, G; Schalk, T; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dvoretskii, A; Fang, F; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Mancinelli, G; Meadows, B T; Mishra, K; Sokoloff, M D; Blanc, F; Bloom, P C; Chen, S; Ford, W T; Hirschauer, J F; Kreisel, A; Nagel, M; Nauenberg, U; Olivas, A; Ruddick, W O; Smith, J G; Ulmer, K A; Wagner, S R; Zhang, J; Chen, A; Eckhart, E A; Soffer, A; Toki, W H; Wilson, R J; Winklmeier, F; Zeng, Q; Altenburg, D D; Feltresi, E; Hauke, A; Jasper, H; Merkel, J; Petzold, A; Spaan, B; Brandt, T; Klose, V; Lacker, H M; Mader, W F; Nogowski, R; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Volk, A; Bernard, D; Bonneaud, G R; Latour, E; Thiebaux, C; Verderi, M; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Robertson, A I; Xie, Y; Andreotti, M; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Petrella, A; Piemontese, L; Prencipe, E; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; De Sangro, R; Finocchiaro, G; Pacetti, S; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Lo Vetere, M; Macri, M M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Brandenburg, G; Chaisanguanthum, K S; Morii, M; Wu, J; Dubitzky, R S; Marks, J; Schenk, S; Uwer, U; Bard, D; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Flack, R L; Nash, J A; Nikolich, M B; Panduro-Vazquez, W; Behera, P K; Chai, X; Charles, M J; Mallik, U; Meyer, N T; Ziegler, V; Cochran, J; Crawley, H B; Dong, L; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gritsan, A V; Denig, A G; Fritsch, M; Schott, G; Arnaud, N; Davier, M; Grosdidier, G; Höcker, A; Le Diberder, F R; Lepeltier, V; Lutz, A M; Oyanguren, A; Pruvot, S; Rodier, S; Roudeau, P; Schune, M H; Stocchi, A; Wang, W F; Wormser, G; Cheng, C H; Lange, D J; Wright, D M; Chavez, C A; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; George, K A; Hutchcroft, D E; Payne, D J; Schofield, K C; Touramanis, C; Bevan, A J; Di Lodovico, F; Menges, W; Sacco, R; Cowan, G; Flächer, H U; Hopkins, D A; Jackson, P S; McMahon, T R; Ricciardi, S; Salvatore, F; Wren, A C; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Chia, Y M; Edgar, C L; Lafferty, G D; Naisbit, M T; Williams, J C; Yi, J I; Chen, C; Hulsbergen, W D; Jawahery, A; Lae, C K; Roberts, D A; Simi, G; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Li, X; Moore, T B; Saremi, S; Stängle, H; Cowan, R; Sciolla, G; Sekula, S J; Spitznagel, M; Taylor, F; Yamamoto, R K; Kim, H; Mclachlin, S E; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Simard, M; Taras, P; Viaud, F B; Nicholson, H; Cavallo, N; De Nardo, Gallieno; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M A; Raven, G; Snoek, H L; Jessop, C P; LoSecco, J M; Allmendinger, T; Benelli, G; Corwin, L A; Gan, K K; Honscheid, K; Hufnagel, D; Jackson, P D; Kagan, H; Kass, R; Rahimi, A M; Regensburger, J J; Ter-Antonian, R; Wong, Q K; Blount, N L; Brau, J E; Frey, R; Igonkina, O; Kolb, J A; Lu, M; Rahmat, R; Sinev, N B; Strom, D; Strube, J; Torrence, E; Gaz, A; Margoni, M; Morandin, M; Pompili, A; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; Del Buono, L; La Vaissière, C de; Hamon, O; Hartfiel, B L; John, M J J; Leruste, P; Malcles, J; Ocariz, J; Roos, L; Therin, G; Gladney, L; Panetta, J; Biasini, M; Covarelli, R; Angelini, C; Batignani, G; Bettarini, S; Bucci, F; Calderini, G; Carpinelli, M; Cenci, R; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Mazur, M A; Morganti, M; Neri, N; Rizzo, G; Walsh, J J; Haire, M; Judd, D; Wagoner, D E; Biesiada, J; Danielson, N; Elmer, P; Lau, Y P; Lü, C; Olsen, J; Smith, A J S; Telnov, A V; Bellini, F; Cavoto, G; D'Orazio, A; Del Re, D; Di Marco, E; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Li Gioi, L; Mazzoni, M A; Morganti, S; Piredda, G; Polci, F; Safai-Tehrani, F; Voena, C; Ebert, M; Schröder, H; Waldi, R; Adye, T; De Groot, N; Franek, B; Olaiya, E O; Wilson, F F; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; Hamel de Monchenault, G; Kozanecki, Witold; Legendre, M; Vasseur, G; Yéche, C; Zito, M; Chen, X R; Liu, H; Park, W; Purohit, M V; Wilson, J R; Allen, M T; Aston, D; Bartoldus, R; Bechtle, P; Berger, N; Claus, R; Coleman, J P; Convery, M R; Cristinziani, M; Dingfelder, J C; Dorfan, J; Dubois-Felsmann, G P; Dujmic, D; Dunwoodie, W M; Field, R C; Glanzman, T; Gowdy, S J; Graham, M T; Grenier, P; Halyo, V; Hast, C; Hrynóva, T; Innes, W R; Kelsey, M H; Kim, P; Leith, D W G S; Li, S; Luitz, S; Lüth, V; Lynch, H L; MacFarlane, D B; Marsiske, H; Messner, R; Müller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Pulliam, T; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Stelzer, J; Su, D; Sullivan, M K; Suzuki, K; Swain, S K; Thompson, J M; Vavra, J; Van Bakel, N; Weaver, M; Weinstein, A J R; Wisniewski, W J; Wittgen, M; Wright, D H; Yarritu, A K; Yi, K; Young, C C; Burchat, P R; Edwards, A J; Majewski, S A; Petersen, B A; Roat, C; Wilden, L; Ahmed, S; Alam, M S; Bula, R; Ernst, J A; Jain, V; Pan, B; Saeed, M A; Wappler, F R; Zain, S B; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Ritchie, J L; Satpathy, A; Schilling, C J; Schwitters, R F; Izen, J M; Lou, X C; Ye, S; Bianchi, F; Gallo, F; Gamba, D; Bomben, M; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Dittongo, S; Lanceri, L; Vitale, L; Azzolini, V; Lopez-March, N; Martínez-Vidal, F; Banerjee, S; Bhuyan, B; Brown, C M; Fortin, D; Hamano, K; Kowalewski, R V; Nugent, I M; Roney, J M; Sobie, R J; Back, J J; Harrison, P F; Latham, T E; Mohanty, G B; Pappagallo, M; Band, H R; Chen, X; Cheng, B; Dasu, S; Datta, M; Flood, K T; Hollar, J J; Kutter, P E; Mellado, B; Mihályi, A; Pan, Y; Pierini, M; Prepost, R; Wu, S L; Yu, Z; Neal, H
2006-01-01
The Xi(1690)0 resonance is observed in the Lambda anti-K0 channel in the decay Lambdac+ --> Lambda anti-K0 K+, from a data sample corresponding to a total integrated luminosity of ~ 200 fb-1 recorded by the Babar detector at the PEPII asymmetric-energy e+ e- collider operating at ~ 10.58 GeV and ~ 10.54 GeV center-of-mass energies. A fit to the Dalitz plot intensity distribution corresponding to the coherent superposition of amplitudes describing Lambda a0(980)+ and Xi(1690)0 K+ production yields mass and width values of 1684.7 +/- 1.3 (stat.) +2.2 -1.6 (syst.) MeV/c2, and $8.1 +3.9 -3.5 (stat.) +1.0 -0.9 (syst.) MeV, respectively, for the Xi(1690)0, while the spin is found to be consistent with value of 1/2 on the basis of studies of the (Lambda KS) angular distribution.
Dipole strength distribution of {sup 50}Ti
Gayer, Udo; Beck, Tobias; Beller, Jacob; Mertes, Laura; Pai, Haridas; Pietralla, Norbert; Ries, Philipp; Romig, Christopher; Werner, Volker; Zweidinger, Markus [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany)
2015-07-01
A first nuclear resonance fluorescence (NRF) experiment with a 68% isotopically enriched {sup 50}Ti target has been performed at the superconducting Darmstadt electron linear accelerator S-DALINAC to investigate particle-bound dipole excitations in this nucleus. The target was irradiated with an unpolarized bremsstrahlung photon beam at endpoint energies of 7.5 MeV and 9.7 MeV. The observed excited states are analyzed with respect to their excitation energies, spin quantum numbers and transition strengths. A complementary NRF experiment with polarized photons will be conducted at the High Intensity gamma-ray Source in Durham, NC, USA to determine the polarity of the dipole transitions. Data will be analyzed with regard to the Pygmy Dipole Resonance, a weakly-collective electric dipole excitation which starts to form in nuclei of this mass region. The measured transition strengths will be compared to microscopic calculations in the quasiparticle-phonon model. The investigation of the magnetic dipole strength distribution will focus on strong spin-flip transitions between the p,f spin-orbit partners expected in the nuclear shell model. First results of the measurements and the evaluation will be presented and discussed.
Correlation Widths in Quantum--Chaotic Scattering
Dietz, B.; Richter, A; WeidenmÜller, H.
2011-01-01
An important parameter to characterize the scattering matrix S for quantum-chaotic scattering is the width Gamma_{corr} of the S-matrix autocorrelation function. We show that the "Weisskopf estimate" d/(2pi) sum_c T_c (where d is the mean resonance spacing, T_c with 0
Properties and significance of the surface dipole mode
Papakonstantinou, P
2014-01-01
A strong isoscalar dipole resonance is known to be excited in a variety of nuclei, including isospin symmetric ones, at approximately 6-7 MeV. A series of theoretical studies and accumulating experimental evidence support an interpretation of the above dipole resonance as an elementary surface vibration. Obviously, such a mode is potentially as interesting as any collective excitation for a variety of reasons. In addition, though, it is found to account for the observed isoscalar segment of pygmy dipole strength. As discussed here, this has important implications for pygmy-strength interpretations and searches for genuine neutron-skin oscillations.
A plasmonic dipole optical antenna coupled quantum dot infrared photodetector
Mojaverian, Neda; Gu, Guiru; Lu, Xuejun
2015-12-01
In this paper, we report a full-wavelength plasmonic dipole optical antenna coupled quantum dot infrared photodetector (QDIP). The plasmonic dipole optical antenna can effectively modify the EM wave distribution and convert free-space propagation infrared light to localized surface plasmonic resonance (SPR) within the nanometer (nm) gap region of the full-wavelength dipole antenna. The plasmonic dipole optical antenna coupled QDIP shows incident-angle-dependent photocurrent enhancement. The angular dependence follows the far-field pattern of a full-wavelength dipole antenna. The directivity of the plasmonic dipole optical antenna is measured to be 1.8 dB, which agrees well with the antenna simulation. To our best knowledge, this is the first report of the antenna far-field and directivity measurement. The agreement of the detection pattern and the directivity with antenna theory confirms functions of an optical antenna are similar to that of a RF antenna.
Low lying excitations in odd deformed nucleus studied by nuclear resonance fluorescence
Pinto, A.E. Almeida [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Margraf, J.; Nord, A. [Stuttgart Univ. (Germany). Inst. fuer Strahlenphysik] [and others
1997-12-31
Nuclear resonance fluorescence experiment was performed on {sup 153} Eu using the Bremsstrahlung beam of the Stuttgart Dynamitron and high resolution Ge-{gamma}-spectrometers. Detailed information was obtained on excitation energies, decay widths, transition probabilities, and branching ratios to study the fragmentation of the M1 scissors mode, and try establishing a systematics to explain the different fragmentation behavior of the dipole strengths in the odd isotopes recently studied. (author) 11 refs., 1 fig.; emilia at axpfep1.if.usp.br
Fosco, César D. [Centro Atómico Bariloche, Instituto Balseiro, Comisión Nacional de Energía Atómica, R8402AGP, Bariloche (Argentina); Lombardo, Fernando C., E-mail: lombardo@df.uba.ar [Departamento de Física Juan José Giambiagi, FCEyN UBA and IFIBA CONICET-UBA, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, Pabellón I, 1428, Buenos Aires (Argentina)
2015-12-17
We study the properties of the classical electromagnetic radiation produced by two physically different yet closely related systems, which may be regarded as classical analogues of the dynamical Casimir effect. They correspond to two flat, infinite, parallel planes, one of them static and imposing perfect-conductor boundary conditions, while the other performs a rigid oscillatory motion. The systems differ just in the electrical properties of the oscillating plane: one of them is just a planar dipole layer (representing, for instance, a small-width electret). The other, instead, has a dipole layer on the side which faces the static plane, but behaves as a conductor on the other side: this can be used as a representation of a conductor endowed with patch potentials (on the side which faces the conducting plane). We evaluate, in both cases, the dissipative flux of energy between the system and its environment, showing that, at least for small mechanical oscillation amplitudes, it can be written in terms of the dipole layer autocorrelation function. We show that there are resonances as a function of the frequency of the mechanical oscillation.
Fosco, Cesar D. [Comision Nacional de Energia Atomica, Centro Atomico Bariloche, Instituto Balseiro, Bariloche (Argentina); Lombardo, Fernando C. [Ciudad Universitaria, Departamento de Fisica Juan Jose Giambiagi, FCEyN UBA y IFIBA CONICET-UBA, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina)
2015-12-15
We study the properties of the classical electromagnetic radiation produced by two physically different yet closely related systems, which may be regarded as classical analogues of the dynamical Casimir effect. They correspond to two flat, infinite, parallel planes, one of them static and imposing perfect-conductor boundary conditions, while the other performs a rigid oscillatory motion. The systems differ just in the electrical properties of the oscillating plane: one of them is just a planar dipole layer (representing, for instance, a small-width electret). The other, instead, has a dipole layer on the side which faces the static plane, but behaves as a conductor on the other side: this can be used as a representation of a conductor endowed with patch potentials (on the side which faces the conducting plane). We evaluate, in both cases, the dissipative flux of energy between the system and its environment, showing that, at least for small mechanical oscillation amplitudes, it can be written in terms of the dipole layer autocorrelation function. We show that there are resonances as a function of the frequency of the mechanical oscillation. (orig.)
Simoni, Paolo; Jamali, Sanaa; Alvarez Miezentseva, Victoria [CHU de Liege, Diagnostic Imaging Departement, Domanine du Sart Tilman, Liege (Belgium); Albert, Adelin [CHU de Liege, Biostatistics Departement, Domanine du Sart Tilman, Liege (Belgium); Totterman, Saara; Schreyer, Edward; Tamez-Pena, Jose G. [Qmetrics Technologies, Rochester, NY (United States); Zobel, Bruno Beomonte [Campus Bio-Medico University, Diagnostic Imaging Departement, Rome (Italy); Gillet, Philippe [CHU de Liege, Orthopaedic surgery Department, Domanine du Sart Tilman, Liege (Belgium)
2013-11-15
To assess the intraobserver, interobserver, and test-retest reproducibility of minimum joint space width (mJSW) measurement of medial and lateral patellofemoral joints on standing ''skyline'' radiographs and to compare the mJSW of the patellofemoral joint to the mean cartilage thickness calculated by quantitative magnetic resonance imaging (qMRI). A couple of standing ''skyline'' radiographs of the patellofemoral joints and MRI of 55 knees of 28 volunteers (18 females, ten males, mean age, 48.5 {+-} 16.2 years) were obtained on the same day. The mJSW of the patellofemoral joint was manually measured and Kellgren and Lawrence grade (KLG) was independently assessed by two observers. The mJSW was compared to the mean cartilage thickness of patellofemoral joint calculated by qMRI. mJSW of the medial and lateral patellofemoral joint showed an excellent intraobserver agreement (interclass correlation (ICC) = 0.94 and 0.96), interobserver agreement (ICC = 0.90 and 0.95) and test-retest agreement (ICC = 0.92 and 0.96). The mJSW measured on radiographs was correlated to mean cartilage thickness calculated by qMRI (r = 0.71, p < 0.0001 for the medial PFJ and r = 0.81, p < 0.0001 for the lateral PFJ). However, there was a lack of concordance between radiographs and qMRI for extreme values of joint width and KLG. Radiographs yielded higher joint space measures than qMRI in knees with a normal joint space, while qMRI yielded higher joint space measures than radiographs in knees with joint space narrowing and higher KLG. Standing ''skyline'' radiographs are a reproducible tool for measuring the mJSW of the patellofemoral joint. The mJSW of the patellofemoral joint on radiographs are correlated with, but not concordant with, qMRI measurements. (orig.)
Massarczyk, Ralph Jens
2011-01-17
During the last hundred years several models were developed to describe the configuration of nuclei. These models have to make predictions, which should be comparable with experiments. As a standard type of experiment the nuclear resonance fluorescence was established. A nucleus is excited by irradiation with photons. By emitting one or more photons the nucleus decays back to the ground state. With this method it is possible to measure energy levels and to determine the strength of their excitation. A continuum of unresolved peaks gives additional strength. The existing setup at the linear electron accelerator ELBE of the Forschungszentrum Dresden-Rossendorf uses bremsstrahlung, produced as a secondary beam in a thin Niobium foil. During the years 2008/09 experiments on the nuclei of {sup 86}Kr and {sup 136}Ba took place there. In this work they will be analyzed. Photon flux and efficiency determination have been done as well as simulations on detector response and non-nuclear scattered background events. For this purpose the GEANT4 package was used. Finally the resulting cross sections were corrected for branching and feeding.
an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...... theoretical consciousness through historical narrative ‘in practice’, by discussing selected historical topics from Western cultural history, within the disciplines of history, literature, visual arts, musicology, archaeology, philosophy, and theology. The title Resonances indicates the overall perspective...
Bubnov, Igor N.; Falkovych, I. S.; Gridin, A. A.; Stanislavsky, A. A.; Reznik, A. P.
2015-01-01
Advantages of the diamond dipole antenna as an active antenna are presented. Such an antenna is like an inverted bow-tie antenna, but the former has some advantages over the ordinary bow-tie antenna. It is shown that the diamond dipole antenna may be an effective element of a new antenna array for low-frequency radio astronomy as well as a communication antenna.
Theory of Dipole Induced Electromagnetic Transparency
Puthumpally-Joseph, Raiju; Sukharev, Maxim; Charron, Eric
2015-01-01
A detailed theory describing linear optics of vapors comprised of interacting multi-level quantum emitters is proposed. It is shown both by direct integration of Maxwell-Bloch equations and using a simple analytical model that at large densities narrow transparency windows appear in otherwise completely opaque spectra. The existence of such windows is attributed to overlapping resonances. This effect, first introduced for three-level systems in [R. Puthumpally-Joseph, M. Sukharev, O. Atabek and E. Charron, Phys. Rev. Lett. 113, 163603 (2014)], is due to strongly enhanced dipole-dipole interactions at high emitters' densities. The presented theory extends this effect to the case of multilevel systems. The theory is applied to the D1 transitions of interacting Rb-85 atoms. It is shown that at high atomic densities, Rb-85 atoms can behave as three-level emitters exhibiting all the properties of dipole induced electromagnetic transparency. Applications including slow light and laser pulse shaping are also propose...
Line width of Josephson flux flow oscillators
Koshelets, V.P.; Dmitriev, P.N.; Sobolev, A.S.;
2002-01-01
to be proven before one initiates real FFO applications. To achieve this goal a comprehensive set of line width measurements of the FFO operating in different regimes has been performed. FFOs with tapered shape have been successfully implemented in order to avoid the superfine resonant structure with voltage...... spacing of about 20 nV and extremely low differential resistance, recently observed in the IVC of the standard rectangular geometry. The obtained results have been compared with existing theories and FFO models in order to understand and possibly eliminate excess noise in the FFO. The intrinsic line width...
Optical antennas with sinusoidal modulation in width.
Dikken, Dirk Jan; Segerink, Frans B; Korterik, Jeroen P; Pfaff, Stefan S; Prangsma, Jord C; Herek, Jennifer L
2016-08-08
Small metal structures sustaining plasmon resonances in the optical regime are of great interest due to their large scattering cross sections and ability to concentrate light to subwavelength volumes. In this paper, we study the dipolar plasmon resonances of optical antennas with a constant volume and a sinusoidal modulation in width. We experimentally show that by changing the phase of the width-modulation, with a small 10 nm modulation amplitude, the resonance shifts over 160 nm. Using simulations we show how this simple design can create resonance shifts greater than 600 nm. The versatility of this design is further shown by creating asymmetric structures with two different modulation amplitudes, which we experimentally and numerically show to give rise to two resonances. Our results on both the symmetric and asymmetric antennas show the capability to control the localization of the fields outside the antenna, while still maintaining the freedom to change the antenna resonance wavelength. The antenna design we tested combines a large spectral tunability with a small footprint: all the antenna dimensions are factor 7 to 13 smaller than the wavelength, and hold potential as a design element in meta-surfaces for beam shaping.
Determination of the dipole moment of OCS with a microwave absorption cavity
Dijkerman, H.A.; Ruitenberg, G.
1969-01-01
The electric dipole moment of OCS has been measured with a resonance cavity as a Stark absorption cell. The result: μOCS = 0.7149 ± 0.0003. Debye agrees well with the dipole moment data obtained with an electric resonance beam experiment.
RHIC AC DIPOLE DESIGN AND CONSTRUCTION.
BAI,M.; METH,M.; PAI,C.; PARKER,B.; PEGGS,S.; ROSER,T.; SANDERS,R.; TRBOJEVIC,D.; ZALTSMAN,A.
2001-06-18
Two ac dipoles with vertical and horizontal magnetic field have been proposed at RHIC for applications in linear and non-linear beam dynamics and spin manipulations. A magnetic field amplitude of 380 Gm is required to produce a coherent oscillation of 5 times the rms beam size at the top energy. We take the ac dipole frequency to be 1.0% of the revolution frequency away from the betatron frequency. To achieve the strong magnetic field with minimum power loss, an air-core magnet with two seven turn winding of low loss Litz wire resonating at 64 kHz is designed. The system is also designed to allow one to connect the two magnet winding in series to resonate at 37 kHz for the spin manipulation. Measurements of a half length prototype magnet are also presented.
Spin Resonance Strength Calculations
Courant, E. D.
2009-08-01
In calculating the strengths of depolarizing resonances it may be convenient to reformulate the equations of spin motion in a coordinate system based on the actual trajectory of the particle, as introduced by Kondratenko, rather than the conventional one based on a reference orbit. It is shown that resonance strengths calculated by the conventional and the revised formalisms are identical. Resonances induced by radiofrequency dipoles or solenoids are also treated; with rf dipoles it is essential to consider not only the direct effect of the dipole but also the contribution from oscillations induced by it.
Spin resonance strength calculations
Courant,E.D.
2008-10-06
In calculating the strengths of depolarizing resonances it may be convenient to reformulate the equations of spin motion in a coordinate system based on the actual trajectory of the particle, as introduced by Kondratenko, rather than the conventional one based on a reference orbit. It is shown that resonance strengths calculated by the conventional and the revised formalisms are identical. Resonances induced by radiofrequency dipoles or solenoids are also treated; with rf dipoles it is essential to consider not only the direct effect of the dipole but also the contribution from oscillations induced by it.
ZHANG Jing-Shang
2004-01-01
In fitting the double-differential measurements thelevelwidth broadening effect should be taken into account properly due to Heisenberg uncertainty.Besides level width broadening effect the energy resolution in the measurements is also needed in this procedure.In general,the traditional normal Gaussian expansion is employed.However,the research indicates that to do so in this way the energy balance could not hold.For this reason,the deformed Gaussian expansion functions with exponential form for both the single energy point and continuous spectrum are introduced,with which the normalization and energy balance conditions could hold exactly in the analytical form.
Dipole blockade in a cold Rydberg atomic sample
Comparat, Daniel; 10.1364/JOSAB.27.00A208
2010-01-01
We review here the studies performed about interactions in an assembly of cold Rydberg atoms. We focus more specially the review on the dipole-dipole interactions and on the effect of the dipole blockade in the laser Rydberg excitation, which offers attractive possibilities for quantum engineering. We present first the various interactions between Rydberg atoms. The laser Rydberg excitation of such an assembly is then described with the introduction of the dipole blockade phenomenon. We report recent experiments performed in this subject by starting with the case of a pair of atoms allowing the entanglement of the wave-functions of the atoms and opening a fascinating way for the realization of quantum bits and quantum gates. We consider then several works on the blockade effect in a large assembly of atoms for three different configurations: blockade through electric-field induced dipole, through F\\"orster resonance and in van der Waals interaction. The properties of coherence and cooperativity are analyzed. ...
Tunable Multiplexed Resonant Dipole Nanoantenna Array Project
National Aeronautics and Space Administration — Radio frequency (RF) spectral density, instrument mass, and power considerations drive developments in construction of nanoscale features and terahertz, even...
Experiments with Dipole Antennas
Kraftmakher, Yaakov
2009-01-01
Employment of a data-acquisition system for data collection and calculations makes experiments with antennas more convenient and less time consuming. The determined directional patterns of the dipole antennas of different lengths are in reasonable agreement with theory. The enhancement of the signal by using a reflector is demonstrated, and a…
Characterizing optical dipole trap via fluorescence of trapped cesium atoms
LIU Tao; GENG Tao; YAN Shubin; LI Gang; ZHANG Jing; WANG Junmin; PENG Kunchi; ZHANG Tiancai
2006-01-01
Optical dipole trap (ODT) is becoming an important tool of manipulating neutral atoms. In this paper ODT is realized with a far-off resonant laser beam strongly focused in the magneto-optical trap (MOT) of cesium atoms. The light shift is measured by simply monitoring the fluorescence of the atoms in the magneto-optical trap and the optical dipole trap simultaneously. The advantages of our experimental scheme are discussed, and the effect of the beam waist and power on the potential of dipole trap as well as heating rate is analyzed.
BEAM MANIPULATION WITH AN RF DIPOLE.
BAI,M.
1999-03-29
Coherent betatron motion adiabatically excited by an RF dipole has been successfully employed to overcome strong intrinsic spin depolarization resonances in the AGS, while a solenoid partial snake has been used to correct imperfection spin resonances. The experimental results showed that a full spin flip was obtained in passing through an intrinsic spin resonance when all the beam particles were forced to oscillate coherently at a large amplitude without diluting the beam emittance. With this method, we have successfully accelerated polarized beam up to 23.5 GeV/c. A new type of second order spin resonances was also discovered. As a non-destructive manipulation, this method can also be used for nonlinear beam dynamics studies and beam diagnosis such as measuring phase advance and betatron amplitude function.
Tonchev, A. P.; Tsoneva, N.; Bhatia, C.; Arnold, C. W.; Goriely, S.; Hammond, S. L.; Kelley, J. H.; Kwan, E.; Lenske, H.; Piekarewicz, J.; Raut, R.; Rusev, G.; Shizuma, T.; Tornow, W.
2017-10-01
A high-resolution study of the electromagnetic response of ^{206}Pb below the neutron separation energy is performed using a (γ→,γ') experiment at the HIγ→S facility. Nuclear resonance fluorescence with 100% linearly polarized photon beams is used to measure spins, parities, branching ratios, and decay widths of excited states in ^{206}Pb from 4.9 to 8.1 MeV. The extracted ΣB(E1)↑ and ΣB(M1)↑ values for the total electric and magnetic dipole strength below the neutron separation energy are 0.9±0.2e^{2}fm^{2} and 8.3±2.0μ$2\\atop{N}$, respectively. These measurements are found to be in very good agreement with the predictions from an energy-density functional (EDF) plus quasiparticle phonon model (QPM). Such a detailed theoretical analysis allows to separate the pygmy dipole resonance from both the tail of the giant dipole resonance and multi-phonon excitations. Combined with earlier photonuclear experiments above the neutron separation energy, one extracts a value for the electric dipole polarizability of ^{206}Pb of α_{D}=122±10mb/MeV. When compared to predictions from both the EDF+QPM and accurately calibrated relativistic EDFs, one deduces a range for the neutron-skin thickness of R$206\\atop{skin}$=0.12–0.19fm and a corresponding range for the slope of the symmetry energy of L=48–60MeV. This newly obtained information is also used to estimate the Maxwellian-averaged radiative cross section _{205}Pb(n,γ)Pb_{206} at 30 keV to be σ=130±25mb. The astrophysical impact of this measurement—on both the s-process in stellar nucleosynthesis and on the equation of state of neutron-rich matter—is discussed.
Final Report: Levitated Dipole Experiment
Kesner, Jay [Massachusetts Institute of Technology, Cambridge, MA (United States); Mauel, Michael [Columbia Univ., New York, NY (United States)
2013-03-10
Since the very first experiments with the LDX, research progress was rapid and significant. Initial experiments were conducted with the high-field superconducting coil suspended by three thin rods. These experiments produced long-pulse, quasi-steady-state microwave discharges, lasting more than 10 s, having peak beta values of 20% [Garnier et al., Physics of Plasmas, 13 (2006) 056111]. High- beta, near steady-state discharges have been maintained in LDX for more than 20 seconds, and this capability made LDX the longest pulse fusion confinement experiment operating in the U.S. fusion program. A significant measure of progress in the LDX research program was the routine investigation of plasma confinement with a magnetically-levitated dipole and the resulting observations of confinement improvement. In both supported and levitated configurations, detailed measurements were made of discharge evolution, plasma dynamics and instability, and the roles of gas fueling, microwave power deposition profiles, and plasma boundary shape. High-temperature plasma was created by multi frequency electron cyclotron resonance heating at 2.45 GHz, 6.4 GHz, 10.5 GHz and 28 GHz allowing control of heating profiles. Depending upon neutral fueling rates, the LDX discharges contain a fraction of energetic electrons, with mean energies above 50 keV. Depending on whether or not the superconducting dipole was levitated or supported, the peak thermal electron temperature was estimated to exceed 500 eV and peak densities to approach 1e18 m^{-3}. We have found that levitation causes a strong inwards density pinch [Boxer et al., Nature Physics, 6 (2010) 207] and we have observed the central plasma density increase dramatically indicating a significant improvement in the confinement of a thermal plasma species.
2004-01-01
The cold mass of a 15-metre main dipole magnet has some fifteen different components. All the main components are manufactured under CERN's direct responsibility. Four of them transit through CERN before being shipped to the dipole assembly contractors, namely the cable, which constitutes the magnet's superconducting core (see Bulletin 14/2004), the beam screens, the heat exchanger tubes and the cold bore beam tubes. The two latter components transit via Building 927 where they undergo part of the production process. The 58-mm diameter heat exchanger tubes will remove heat from the magnets using superfluid helium. The 53-mm diameter cold bore tubes will be placed under vacuum to allow the twin beams to circulate around the LHC.
Maximilien Brice
2004-01-01
The ALICE cavern receives a painting made specially to mark the 50th anniversary of CERN that is mounted on the L3 solenoid magnet, reused from the LEP experiment that ran from 1989 to 2000. The dipole, which is cooled by demineralised water, will bend the path of muons that leave the huge rectangular solenoid. These muons are heavy electrons that interact less with matter allowing them to be studied at large distances from the interaction point.
Giant Primeval Magnetic Dipoles
Thompson, Christopher
2017-07-01
Macroscopic magnetic dipoles are considered cosmic dark matter. Permanent magnetism in relativistic field structures can involve some form of superconductivity, one example being current-carrying string loops (“springs”) with vanishing net tension. We derive the cross-section for free classical dipoles to collide, finding it depends weakly on orientation when mutual precession is rapid. The collision rate of “spring” loops with tension { T }˜ {10}-8{c}4/G in galactic halos approaches the measured rate of fast radio bursts (FRBs) if the loops compose most of the dark matter. A large superconducting dipole (LSD) with mass ˜1020 g and size ˜1 mm will form a ˜100 km magnetosphere moving through interstellar plasma. Although hydromagnetic drag is generally weak, it is strong enough to capture some LSDs into long-lived rings orbiting supermassive black holes (SMBHs) that form by the direct collapse of massive gas clouds. Repeated collisions near young SMBHs could dominate the global collision rate, thereby broadening the dipole mass spectrum. Colliding LSDs produce tiny, hot electromagnetic explosions. The accompanying paper shows that these explosions couple effectively to propagating low-frequency electromagnetic modes, with output peaking at 0.01-1 THz. We describe several constraints on, and predictions of, LSDs as cosmic dark matter. The shock formed by an infalling LSD triggers self-sustained thermonuclear burning in a C/O (ONeMg) white dwarf (WD) of mass ≳1 M ⊙ (1.3 M ⊙). The spark is generally located off the center of the WD. The rate of LSD-induced explosions matches the observed rate of Type Ia supernovae.
Girwidz, Raimund V.
2016-11-01
The Hertzian dipole is fundamental to the understanding of dipole radiation. It provides basic insights into the genesis of electromagnetic waves and lays the groundwork for an understanding of half-wave antennae and other types. Equations for the electric and magnetic fields of such a dipole can be derived mathematically. However these are very abstract descriptions. Interpreting these equations and understanding travelling electromagnetic waves are highly limited in that sense. Visualizations can be a valuable supplement that vividly present properties of electromagnetic fields and their propagation. The computer simulation presented below provides additional instructive illustrations for university lectures on electrodynamics, broadening the experience well beyond what is possible with abstract equations. This paper refers to a multimedia program for PCs, tablets and smartphones, and introduces and discusses several animated illustrations. Special features of multiple representations and combined illustrations will be used to provide insight into spatial and temporal characteristics of field distributions—which also draw attention to the flow of energy. These visualizations offer additional information, including the relationships between different representations that promote deeper understanding. Finally, some aspects are also illustrated that often remain unclear in lectures.
Holanda, B A; Cordeiro, R C; Blak, A R, E-mail: bruna.holanda@usp.br, E-mail: renan.cordeiro@usp.br, E-mail: anablak@if.usp.br
2010-11-15
Dipole defects in gamma irradiated and thermally treated beryl (Be{sub 3}Al{sub 2}Si{sub 6}O{sub 18}) samples have been studied using the Thermally Stimulated Depolarization Currents (TSDC) technique. TSDC experiments were performed in pink (morganite), green (emerald), blue (aquamarine) and colourless (goshenite) natural beryl. TSDC spectra present dipole peaks at 190K, 220K, 280K and 310K that change after gamma irradiation and thermal treatments. In morganite samples, for thermal treatments between 700K and 1100K, the 280K peak increase in intensity and the band at 220K disappears. An increase of the 280K peak and a decrease of the 190K peak were observed in the TSDC spectra of morganite after a gamma irradiation of 25kGy performed after the thermal treatments. In the case of emerald samples, thermal treatments enhanced the 280K peak and gamma irradiation partially destroyed this band. The goshenite TSDC spectra present only one band at 280K that is not affected either by thermal treatments or by gamma irradiation. All the observed peaks are of dipolar origin because the intensity of the bands is linearly dependent on the polarization field, behaviour of dipole defects. The systematic study, by means of TSDC measurements, of ionizing irradiation effects and thermal treatments in these crystals makes possible a better understanding of the role played by the impurities in beryl crystals.
Low-Q Electrically Small Spherical Magnetic Dipole Antennas
Kim, Oleksiy S.
2010-01-01
Three novel electrically small antenna configurations radiating a TE10 spherical mode corresponding to a magnetic dipole are presented and investigated: multiarm spherical helix (MSH) antenna, spherical split ring resonator (S-SRR) antenna, and spherical split ring (SSR) antenna. All three antennas...... are self-resonant, with the input resistance tuned to 50 ohms by an excitation curved dipole/monopole. A prototype of the SSR antenna has been fabricated and measured, yielding results that are consistent with the numerical simulations. Radiation quality factors (Q) of these electrically small antennas (in...
Mustafa, Farahiyah; Hashim, Abdul Manaf; Parimon, Norfarariyanti; Rahman, Shaharin Fadzli Abd; Rahman, Abdul Rahim Abdul [Material Innovations and Nanoelectronics Research Group, Faculty of Electrical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Osman, Mohd Nizam [Telekom Research and Development, TM Innovation Centre, 63000 Cyberjaya (Malaysia); Aziz, Azlan Abdul; Hashim, Md Roslan, E-mail: manaf@fke.utm.my [Nano-Optoelectronics Research, Faculty of Physics, Universiti Sains Malaysia, 11800 Minden, Penang (Malaysia)
2011-02-15
The design and RF characteristics of planar dipole antennas facilitated with coplanar waveguide (CPW) structure on semi-insulated GaAs are performed and confirmed to work in super high frequency (SHF) range. As expected, the fundamental resonant frequency shifts to higher frequency when the length of antenna decreases. Interestingly, the resonant frequencies of antenna are almost unchanged with the variation of antenna width and metal thickness. It is shown experimentally that return loss down to -54 dB with a metal thickness of 50 nm is obtainable. Preliminary investigation on design, fabrication, and DC and RF characteristics of the integrated device (planar dipole antenna + Schottky diode) on AlGaAs/GaAs HEMT structure is presented. From the preliminary direct irradiation experiments using the integrated device, the Schottky diode is not turned on due to weak reception of RF signal by dipole antenna. Further extensive considerations on the polarization of irradiation etc. need to be carried out in order to improve the signal reception. These preliminary results provide a new breakthrough for on-chip electronic device application in nanosystems.
Bounding the Higgs boson width through interferometry.
Dixon, Lance J; Li, Ye
2013-09-13
We study the change in the diphoton-invariant-mass distribution for Higgs boson decays to two photons, due to interference between the Higgs resonance in gluon fusion and the continuum background amplitude for gg→γγ. Previously, the apparent Higgs mass was found to shift by around 100 MeV in the standard model in the leading-order approximation, which may potentially be experimentally observable. We compute the next-to-leading-order QCD corrections to the apparent mass shift, which reduce it by about 40%. The apparent mass shift may provide a way to measure, or at least bound, the Higgs boson width at the Large Hadron Collider through "interferometry." We investigate how the shift depends on the Higgs width, in a model that maintains constant Higgs boson signal yields. At Higgs widths above 30 MeV, the mass shift is over 200 MeV and increases with the square root of the width. The apparent mass shift could be measured by comparing with the ZZ* channel, where the shift is much smaller. It might be possible to measure the shift more accurately by exploiting its strong dependence on the Higgs transverse momentum.
Quantum emitter dipole-dipole interactions in nanoplasmonic systems
Nečada, Marek; Törmä, Päivi
2016-01-01
We introduce a generalized Dicke-like model to describe two-level systems coupled with a single bosonic mode. In addition, the two-level systems mutually interact via direct dipole-dipole interaction. We apply the model to an ensemble of dye molecules coupled to a plasmonic excitation in a metallic nanoparticle and study how the dipole-dipole interaction and configurational randomness introduced to the system affect the energy spectra. Comparing the system eigenenergies obtained by our model with the light spectra from a multiple-scattering simulation, we suggest a way to identify dark modes in our model. Finally, we perform a parameter sweep in order to determine the scaling properties of the system and to classify the regions of the parameter space where the dipole-dipole interactions can have significant effects.
EM design and analysis of dipole arrays on non-planar dielectric substrate
Singh, Hema; Jha, Rakesh Mohan
2016-01-01
This book presents a simple and systematic description of EM design of antenna arrays. Printed dipole antennas are known to be simple yet more efficient than wire antennas. The dielectric substrate and the presence of ground plane affect the antenna performance and the resonant frequency is shifted. This book includes the EM design and performance analysis of printed dipole arrays on planar and cylindrical substrates. The antenna element is taken as half-wave centre-fed dipole. The substrate is taken as low-loss dielectric. The effect of substrate material, ground plane, and the curvature effect is discussed. Results are presented for both the linear and planar dipole arrays. The performance of dipole array is analyzed in terms of input impedance, return loss, and radiation pattern for different configurations. The effect of curved platform (substrate and ground plane) on the radiation behaviour of dipole array is analyzed. The book explains fundamentals of EM design and analysis of dipole antenna array throu...
Optimized tapered dipole nanoantenna as efficient energy harvester.
El-Toukhy, Youssef M; Hussein, Mohamed; Hameed, Mohamed Farhat O; Heikal, A M; Abd-Elrazzak, M M; Obayya, S S A
2016-07-11
In this paper, a novel design of tapered dipole nanoantenna is introduced and numerically analyzed for energy harvesting applications. The proposed design consists of three steps tapered dipole nanoantenna with rectangular shape. Full systematic analysis is carried out where the antenna impedance, return loss, harvesting efficiency and field confinement are calculated using 3D finite element frequency domain method (3D-FEFD). The structure geometrical parameters are optimized using particle swarm algorithm (PSO) to improve the harvesting efficiency and reduce the return loss at wavelength of 500 nm. A harvesting efficiency of 55.3% is achieved which is higher than that of conventional dipole counterpart by 29%. This enhancement is attributed to the high field confinement in the dipole gap as a result of multiple tips created in the nanoantenna design. Furthermore, the antenna input impedance is tuned to match a wide range of fabricated diode based upon the multi-resonance characteristic of the proposed structure.
Retardation effects in induced atomic dipole-dipole interactions
Graham, S D
2016-01-01
We present mean-field calculations of azimuthally averaged retarded dipole-dipole interactions in a Bose-Einstein condensate induced by a laser, at both long and short wavelengths. Our calculations demonstrate that dipole-dipole interactions become significantly stronger at shorter wavelengths, by as much as 30-fold, due to retardation effects. This enhancement, along with inclusion of the dynamic polarizability, indicate a method of inducing long-range interatomic interactions in neutral atom condensates at significantly lower intensities than previously realized.
Egorova, Irina A
2016-01-01
New results for electric dipole strength in the chain of even-even Calcium isotopes with the mass numbers A = 40 - 54 are presented. Starting from the covariant Lagrangian of Quantum Hadrodynamics, spectra of collective vibrations (phonons) and phonon-nucleon coupling vertices for $J \\leq 6$ and normal parity were computed in a self-consistent relativistic quasiparticle random phase approximation (RQRPA). These vibrations coupled to Bogoliubov two-quasiparticle configurations (2q$\\otimes$phonon) form the model space for the calculations of the dipole response function in the relativistic quasiparticle time blocking approximation (RQTBA). The results for giant dipole resonance in the latter approach are compared to those obtained in RQRPA and to available data. Evolution of the dipole strength with neutron number is investigated for both high-frequency giant dipole resonance (GDR) and low-lying strength. Development of a pygmy resonant structure on the low-energy shoulder of GDR is traced and analyzed in terms...
Superconducting dipole electromagnet
Purcell, John R.
1977-07-26
A dipole electromagnet of especial use for bending beams in particle accelerators is wound to have high uniformity of magnetic field across a cross section and to decrease evenly to zero as the ends of the electromagnet are approached by disposing the superconducting filaments of the coil in the crescent-shaped nonoverlapping portions of two intersecting circles. Uniform decrease at the ends is achieved by causing the circles to overlap increasingly in the direction of the ends of the coil until the overlap is complete and the coil is terminated.
Isoscalar dipole transition as a probe for asymmetric clustering
Chiba, Y; Taniguchi, Y
2015-01-01
Background: The sharp $1^-$ resonances with enhanced isoscalar dipole transition strengths are observed in many light nuclei at relatively small excitation energies, but their nature was unclear. Purpose: We show those resonances can be attributed to the cluster states with asymmetric configurations such as $\\alpha$+$^{16}{\\rm O}$. We explain why asymmetric cluster states are strongly excited by the isoscalar dipole transition. We also provide a theoretical prediction of the isoscalar dipole transitions in $^{20}{\\rm Ne}$ and $^{44}{\\rm Ti}$. Method: The transition matrix is analytically derived to clarify the excitation mechanism. The nuclear model calculations by Brink-Bloch wave function and antisymmetrized molecular dynamics are also performed to provide a theoretical prediction for $^{20}{\\rm Ne}$ and $^{44}{\\rm Ti}$. Results: It is shown that the transition matrix is as large as the Weisskopf estimate even though the ground state is an ideal shell model state. Furthermore, it is considerably amplified i...
Magnetic dipole states in /sup 206/Pb
Ponomarev, V.; Vdovin, A.; Velchev, Ch.
1987-12-01
The fragmentation of the magnetic dipole strength in /sup 206/Pb is studied in the framework of the quasiparticle-phonon nuclear model. The calculations reproduce the two-humped shape of the experimental distribution. As in /sup 208/Pb there is an isoscalar 1/sup +/ state at Esub(x) approx. = 5.7 MeV in /sup 206/Pb and its wavefunction contains sizable two-photon components. It is shown that direct transitions from the ground state to two-phonon 1/sup +/ states give a negligible contribution to the total excitation probability of the M1 resonance.
Rossi, Dominic M.
2010-01-25
The electric dipole response of neutron-rich nickel isotopes has been investigated using the LAND setup at GSI in Darmstadt (Germany). Relativistic secondary beams of {sup 56-57}Ni and {sup 67-72}Ni at approximately 500 AMeV have been generated using projectile fragmentation of stable ions on a 4 g/cm{sup 2} Be target and subsequent separation in the magnetic dipole fields of the FRagment Separator (FRS). After reaching the LAND setup in Cave C, the radioactive ions were excited electromagnetically in the electric field of a Pb target. The decay products have been measured in inverse kinematics using various detectors. Neutron-rich {sup 67-69}Ni isotopes decay by the emission of neutrons, which are detected in the LAND detector. The present analysis concentrates on the ({gamma},n) and ({gamma},2n) channels in these nuclei, since the proton and three-neutron thresholds are unlikely to be reached considering the virtual photon spectrum for nickel ions at 500 AMeV. A measurement of the stable {sup 58}Ni isotope is used as a benchmark to check the accuracy of the present results with previously published data. The measured ({gamma},n) and ({gamma},np) channels are compared with an inclusive photoneutron measurement by Fultz and coworkers, which are consistent within the respective errors. The measured excitation energy distributions of {sup 67-69}Ni contain a large portion of the Giant Dipole Resonance (GDR) strength predicted by the Thomas-Reiche-Kuhn energy-weighted sum rule, as well as a significant amount of low-lying E1 strength, that cannot be attributed to the GDR alone. The GDR distribution parameters are calculated using well-established semi-empirical systematic models, providing the peak energies and widths. The GDR strength is extracted from the {chi}{sup 2} minimization of the model GDR to the measured data of the ({gamma},2n) channel, thereby excluding any influence of eventual low-lying strength. The subtraction of the obtained GDR distribution from the
Magnetic dipole moment of a moving electric dipole
Hnizdo, V.
2012-01-01
The current density of a moving electric dipole is expressed as the sum of polarization and magnetization currents. The magnetic field due to the latter current is that of a magnetic dipole moment that is consistent with the relativistic transformations of the polarization and magnetization of macroscopic electrodynamics.
"Bi-modal" isoscalar giant dipole strength in Ni-58
Nayak, B. K.; Garg, U.; Hedden, M.; Koss, M.; Li, T.; Liu, Y.; Rao, P. V. Madhusudhana; Zhu, S.; Itoh, M.; Sakaguchi, H.; Takeda, H.; Uchida, M.; Yasuda, Y.; Yosoi, M.; Fujimura, H.; Fujiwara, M.; Hara, K.; Kawabata, T.; Akimune, H.; Harakeh, M. N.
2006-01-01
The strength distribution of the isoscalar giant dipole resonance (ISGDR) in Ni-58 has been obtained over the energy range 10.5-49.5 MeV via extreme forward angle scattering (including 0 degrees) of 386 MeV alpha particles. We observe a "bi-modal" El strength distribution for the first time in an A
Microscopic structure of the dipole compression mode in heavy nuclei
Harakeh, M. N.
2006-01-01
Neutron decay of the isoscalar giant dipole resonance (ISGDR) has been studied in Zr-90, Sn-116 and Pb-208 using the (alpha, alpha') reaction at a bombarding energy of 200 MeV. The same reaction was used to study proton decay of the ISGDR in Ni-58 and Pb-208. Neutron and proton decay of the ISGDR to
Spin-dipole excitations studied with tensor polarised deuteron beams
Wortche, H. J.; Julin, R; Demetriuo, P; Harissopulos, SV
2008-01-01
Taking advantage of the spin, isospin and J(pi) selectivity of cross sections and analysing powers of the tensor polarised C-12 (d(->), He-2) reaction, the J(pi) = 0(-), 1(-), 2(-) components of the spin-dipole resonance in B-12 have been investigated. The experiment was performed at the Big-Bite Sp
SPS Dipole Multipactor Test and TEWave Diagnostics
Caspers, F; Edwards, P; Federmann, S; Holz, M; Taborelli, M
2013-01-01
Electron cloud accumulation in particle accelerators can be mitigated by coating the vacuum beam pipe with thin films of low secondary electron yield (SEY) material. The SEY of small coated samples are usually measured in the laboratory. To further test the properties of different coating materials, RF-induced multipacting in a coaxial waveguide configuration can be performed. The technique is applied to two main bending dipoles of the SPS, where the RF power is fed through a tungsten wire stretched along the vacuum chamber (6.4 m). A dipole with a bare stainless steel chamber shows a clear power threshold initiating an abrupt rise in reflected power and pressure. The effect is enhanced at RF frequencies corresponding to electron cyclotron resonances for given magnetic fields. Preliminary results show that the dipole with a carbon coated vacuum chamber does not exhibit any pressure rise or reflected RF power up to the maximum available input power. In the case of a large scale coating production this techniqu...
Pygmy dipole strength close to particle-separation energies - the case of the Mo isotopes
Rusev, G; Erhard, M; Junghans, A; Kosev, K; Schilling, K D; Schwengner, R; Wagner, A; Rusev, Gencho; Grosse, Eckart; Erhard, Martin; Junghans, Arnd; Kosev, Krasimir; Schilling, Klaus-Dieter; Schwengner, Ronald; Wagner, Andreas
2005-01-01
The distribution of electromagnetic dipole strength in 92, 98, 100 Mo has been investigated by photon scattering using bremsstrahlung from the new ELBE facility. The experimental data for well separated nuclear resonances indicate a transition from a regular to a chaotic behaviour above 4 MeV of excitation energy. As the strength distributions follow a Porter-Thomas distribution much of the dipole strength is found in weak and in unresolved resonances appearing as fluctuating cross section. An analysis of this quasi-continuum - here applied to nuclear resonance fluorescence in a novel way - delivers dipole strength functions, which are combining smoothly to those obtained from (g,n)-data. Enhancements at 6.5 MeV and at ~9 MeV are linked to the pygmy dipole resonances postulated to occur in heavy nuclei.
Probabilistic Analysis of Crack Width
J. Marková
2000-01-01
Full Text Available Probabilistic analysis of crack width of a reinforced concrete element is based on the formulas accepted in Eurocode 2 and European Model Code 90. Obtained values of reliability index b seem to be satisfactory for the reinforced concrete slab that fulfils requirements for the crack width specified in Eurocode 2. However, the reliability of the slab seems to be insufficient when the European Model Code 90 is considered; reliability index is less than recommended value 1.5 for serviceability limit states indicated in Eurocode 1. Analysis of sensitivity factors of basic variables enables to find out variables significantly affecting the total crack width.
A deterministic width function model
C. E. Puente
2003-01-01
Full Text Available Use of a deterministic fractal-multifractal (FM geometric method to model width functions of natural river networks, as derived distributions of simple multifractal measures via fractal interpolating functions, is reported. It is first demonstrated that the FM procedure may be used to simulate natural width functions, preserving their most relevant features like their overall shape and texture and their observed power-law scaling on their power spectra. It is then shown, via two natural river networks (Racoon and Brushy creeks in the United States, that the FM approach may also be used to closely approximate existing width functions.
Final Report: Levitated Dipole Experiment
Kesner, Jay; Mauel, Michael
2013-03-10
Since the very first experiments with the LDX, research progress was rapid and significant. Initial experiments were conducted with the high-field superconducting coil suspended by three thin rods. These experiments produced long-pulse, quasi-steady-state microwave discharges, lasting more than 10 s, having peak beta values of 20% [Garnier, Phys. Plasmas, v13, p. 056111, 2006]. High-beta, near steady-state discharges have been maintained in LDX for more than 20 seconds, and this capability makes LDX the longest pulse fusion confinement experiment now operating in the U.S. fusion program. In both supported and levitated configurations, detailed measurements are made of discharge evolution, plasma dynamics and instability, and the roles of gas fueling, microwave power deposition profiles, and plasma boundary shape. High-temperature plasma is created by multifrequency electron cyclotron resonance heating allowing control of heating profiles. Depending upon neutral fueling rates, the LDX discharges contain a fraction of energetic electrons, with mean energies above 50 keV. Depending on whether or not the superconducting dipole is levitated or supported, the peak thermal electron temperature is estimated to exceed 500 eV and peak densities reach 1.0E18 (1/m3). Several significant discoveries resulted from the routine investigation of plasma confinement with a magnetically-levitated dipole. For the first time, toroidal plasma with pressure approaching the pressure of the confining magnetic field was well-confined in steady-state without a toroidal magnetic field. Magnetic levitation proved to be reliable and is now routine. The dipole's cryostat allows up to three hours of "float time" between re-cooling with liquid helium and providing scientists unprecedented access to the physics of magnetizd plasma. Levitation eliminates field-aligned particle sources and sinks and results in a toroidal, magnetically-confined plasma where profiles are determined by cross
Backfire antennas with dipole elements
Nielsen, Erik Dragø; Pontoppidan, Knud
1970-01-01
A method is set up for a theoretical investigation of arbitrary backfire antennas based upon dipole structures. The mutual impedance between the dipole elements of the antenna is taken into account, and the field radiated due to a surface wave reflector of finite extent is determined by calculating...
Observation of St\\"uckelberg oscillations in dipole-dipole interactions
van Ditzhuijzen, C S E; Heuvell, H B van Linden van den
2009-01-01
We have observed Stueckelberg oscillations in the dipole-dipole interaction between Rydberg atoms with an externally applied radio-frequency field. This proves coherent interaction during at least 0.6 $\\mu$s. The oscillating RF field brings the interaction between cold Rydberg atoms in two separated volumes in resonance and we observe multi-photon transitions when varying the amplitude of the RF-field and the static field offset. The angular momentum states we use show a quadratic Stark shift, which leads to an essentially different behavior than linearly shifting states. Both cases are studied theoretically using the Floquet approach and are compared. The amplitude of the sidebands, related to the interaction strength, is given by the Bessel function in the linearly shifting case and by the generalized Bessel function in the quadratically shifting case. Both functions are further studied in the classical limit. The oscillatory behavior of both functions correspond to Stueckelberg oscillations, an interferenc...
Magnetic Field of a Dipole and the Dipole-Dipole Interaction
Kraftmakher, Yaakov
2007-01-01
With a data-acquisition system and sensors commercially available, it is easy to determine magnetic fields produced by permanent magnets and to study the dipole-dipole interaction for different separations and angular positions of the magnets. For sufficiently large distances, the results confirm the 1/R[superscript 3] law for the magnetic field…
A method to assess the loss of a dipole antenna for ultra-high-field MRI.
Chen, Gang; Collins, Christopher M; Sodickson, Daniel K; Wiggins, Graham C
2017-06-19
To describe a new bench measurement based on quality (Q) factors to estimate the coil noise relative to the sample noise of dipole antennas at 7 T. Placing a dipole antenna close to a highly conductive sample surrogate (HCSS) greatly reduces radiation loss, and using QHCSS gives a more accurate estimate of coil resistance than Qunloaded . Instead of using the ratio of unloaded and sample-loaded Q factors, the ratio of HCSS-loaded and sample-loaded Q factors should be used at ultra-high fields. A series of simulations were carried out to analyze the power budget of sample-loaded or HCSS-loaded dipole antennas. Two prototype dipole antennas were also constructed for bench measurements to validate the simulations. Simulations showed that radiation loss was suppressed when the dipole antenna was HCSS-loaded, and coil loss was largely the same as when the dipole was loaded by the sample. Bench measurements also showed good alignment with simulations. Using the ratio QHCSS /Qloaded gives a good estimate of the coil loss for dipole antennas at 7 T, and provides a convenient bench measurement to predict the body noise dominance of dipole antenna designs. The new approach also applies to conventional surface loop coils at ultra-high fields. Magn Reson Med 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.
Kanada-En'yo, Yoshik
2015-01-01
Isovector and isoscalar dipole excitations in $^9$Be and $^{10}$Be are investigated in the framework of antisymmetrized molecular dynamics, in which angular-momentum and parity projections are performed. In the present method, 1p-1h excitations on the ground state and large amplitude $\\alpha$-cluster mode are incorporated. The isovector giant dipole resonance (GDR) in $E>20$ MeV shows the two peak structure which is understood by the dipole excitation in the 2$\\alpha$ core part with the prolate deformation. Because of valence neutron modes against the $2\\alpha$ core, low-energy E1 resonances appear in $E20$ MeV.
Unveiling Magnetic Dipole Radiation in Phase-Reversal Leaky-Wave Antennas
Gupta, Shulabh; Caloz, Christophe
2014-01-01
The radiation principle of travelling-wave type phase-reversal antennas is explained in details, unveiling the presence of magnetic-dipole radiation in addition to well-known electric dipole radiation. It is point out that such magnetic dipole radiation is specific to the case of traveling-wave phase-reversal antennas whereas only electric-dipole radiation exists in resonant-type phase-reversal antennas. It is shown that a phase-reversal travelling-wave antenna alternately operates as an array of magnetic dipoles and an array of electric-dipoles during a time-harmonic period. This radiation mechanism is confirmed through both full-wave and experimental results.
Emission properties of an oscillating point dipole from a gold Yagi-Uda nanoantenna array
Lobanov, S V; Dregely, D; Giessen, H; Gippius, N A; Tikhodeev, S G
2011-01-01
We investigate numerically the interaction of an oscillating point dipole with a periodic array of optical Yagi-Uda nanoantennas in the weak coupling limit. A very strong near-field enhancement of the dipole emission by the resonant plasmon mode in the feed element is predicted in this structure. It is shown that the enhancement strength depends strongly on the dipole position, the direction of the dipole moment, and the oscillation frequency. The radiative intensity of the point dipole from appropriate places next to one feed element may exceed the radiative intensity of an equivalent dipole in free-space by a factor of hundred. In spite of only one director used in each nanoantenna of the array, the far-field emission pattern is highly directed. The radiative efficiency (the ratio of the radiative to the full emission) appears to be around 20%.
Coupled dipole plasmonics of nanoantennas in discontinuous, complex dielectric environments
Forcherio, Gregory T.; Blake, Phillip; Seeram, Manoj; DeJarnette, Drew; Roper, D. Keith
2015-11-01
Two-dimensional metamaterials support both plasmonic and coupled lattice (Fano) resonant modes that together could enhance optoelectronics. Descriptions for plasmon excitation in Fano resonant lattices in non-vacuum environments typically use idealized, homogeneous matrices due to computational expense and limitations of common approaches. This work described both localized and coupled resonance activity of two-dimensional, square lattices of gold (Au) nanospheres (NS) in discontinuous, complex dielectric media using compact synthesis of discrete and coupled dipole approximations. This multi-scale approach supported attribution of experimentally observed spectral resonance energy and bandwidth to interactions between metal and dielectric substrate(s) supporting the lattices. Effective polarizabilities of single AuNS, either in vacuo or supported by glass and/or indium tin oxide (ITO) substrates, were obtained with discrete dipole approximation (DDA). This showed plasmon energy transport varied with type of substrate: glass increased scattering, while ITO increased absorption and energy confinement. Far-field lattice interactions between AuNS with/without substrates were computed by coupled dipole approximation (CDA) using effective polarizabilities. This showed glass enhanced diffractive features (e.g., coupled lattice resonance), while ITO supported plasmon modes. This compact, multiscale approach to describe metasurfaces in complex environments could accelerate their development and application.
Applicability of point dipoles approximation to all-dielectric metamaterials
Kuznetsova, S M; Lavrinenko, A V
2015-01-01
All-dielectric metamaterials consisting of high-dielectric inclusions in a low-dielectric matrix are considered as a low-loss alternative to resonant metal-based metamaterials. In this contribution we investigate the applicability of the point electric and magnetic dipoles approximation to dielectric meta-atoms on the example of a dielectric ring metamaterial. Despite the large electrical size of high-dielectric meta-atoms, the dipole approximation allows for accurate prediction of the metamaterials properties for the rings with diameters up to ~0.8 of the lattice constant. The results provide important guidelines for design and optimization of all-dielectric metamaterials.
Novel Empirical Equations to Calculate the Impedance of a Strip Dipole Antenna
S. Keyrouz
2013-12-01
Full Text Available This paper investigates the input impedance of strip dipoles since they are the basic elements of folded strip dipole antennas. A novel, simple and accurate design algorithm is presented. Compared to state-of-the art design equations, the new proposed equations are more accurate than those found in the literature and take into consideration the antenna feeding width. These equations reduce the calculation time, when compared to commercial electromagnetic simulation software, allowing for fast antenna designs with very high accuracy. Based on the novel equations, a strip dipole antenna is designed, simulated, manufactured and measured. The simulation results are validated by measurements.
Dipole-Dipole Interactions of Charged Magnetic Grains
Perry, Jonathan; Hyde, Truell
2010-01-01
The interaction between dust grains is an important process in fields as diverse as planetesimal formation or the plasma processing of silicon wafers into computer chips. This interaction depends in large part on the material properties of the grains, for example whether the grains are conducting, non-conducting, ferrous or non-ferrous. This work considers the effects that electrostatic and magnetic forces, alone or in combination, can have on the coagulation of dust in various environments. A numerical model is used to simulate the coagulation of charged, charged-magnetic and magnetic dust aggregates formed from ferrous material and the results are compared to each other as well as to those from uncharged, non-magnetic material. The interactions between extended dust aggregates are also examined, specifically looking at how the arrangement of charge over the aggregate surface or the inclusion of magnetic material produces dipole-dipole interactions. It will be shown that these dipole-dipole interactions can ...
2001-01-01
Andrezej Siemko (left), Peter Sievers (centre), and Lucio Rossi (right), have the exciting challenge of preparing and testing 2000 magnets for the LHC. The LHC is going to require a lot of powerful magnets by the time it begins operation in 2006. More specifically, it is going to need 130 special magnets, 400 quadrupoles, and a whopping 1250 dipoles! Preparing and testing these magnets for the conditions they will encounter in the LHC is not an easy task. But evaluation of the most recently received magnet, from the German company Noell, is showing that while the monumental task of receiving and testing nearly 2000 magnets is going to be exhausting, the goals are definitely attainable. At the moment and over the next year, pre-series magnets (the magnets that CERN uses to fine tune performance) are arriving slowly (90 in total will arrive), but by 2003 the rate of series magnet arrival will accelerate to 9 per week, that's over 450 in a single year! And working with these magnets when they arrive is tough. ...
Fractional vortex dipole phase filter
Sharma, Manoj Kumar; Joseph, Joby; Senthilkumaran, Paramasivam
2014-10-01
In spatial filtering experiments, the use of vortex phase filters plays an important role in realizing isotropic edge enhancement. In this paper, we report the use of a vortex dipole phase filter in spatial filtering. A dipole made of fractional vortices is used, and its filtering characteristics are studied. It is observed that the filter performance can be tuned by varying the distance of separation between the vortices of the dipole to achieve better contrast and output noise suppression, and when this distance tends to infinity, the filter performs like a 1-D Hilbert mask. Experimental and simulation results are presented.
Fermion Dipole Moment and Holography
Kulaxizi, Manuela
2015-01-01
In the background of a charged AdS black hole, we consider a Dirac particle endowed with an arbitrary magnetic dipole moment. For non-zero charge and dipole coupling of the bulk fermion, we find that the dual boundary theory can be plagued with superluminal modes. Requiring consistency of the dual CFT amounts to constraining the strength of the dipole coupling by an upper bound. We briefly discuss the implications of our results for the physics of holographic non-Fermi liquids.
Bahruddin Thalib
2016-04-01
Full Text Available Various types of anatomical landmarks of the face should match its proportions with the size of the teeth which is the interalar width, intercomissural width, interpupillary width, Intercanthal width, and byzigomatic width. Some of face landmarks can be used as a guide in the selection of anterior teeth in complete denture, especially if the pre extraction record such as radiography image, extracted teeth, model study, the remaining teeth, face shape, and the shape of the curved jaw have been lost. The objective of this study was to evaluate the correlation between interalar width and intercommisural width against mesiodistal incisivus centralis width in a group of Buginese tribe. Ninety nine Buginese tribe subjects aged 17-25 were selected. The interalar width, intercommisural width, and mesiodistal incisor centralis teeth were measured using caliper about three times for accuracy and precision. Mean of interalar width and mesiodistal incisor centralis maxilla width in males more width than females (p0.05. The degree of correlation between interalar width against mesiodistal incisor centralis maxilla width was 0.030, -0.246, 0,225 in Buginese tribe, males, and females (p>0.05. : The degree of correlation between intercommisural width against mesiodistal incisor centralis maxilla width in Buginese tribe was 0,054, 0,013, 0,153 in Buginese tribe, males, and females (p>0.05. The degree of correlation between interalar width and intercommisural width was 0.301 and 0.356 in Buginese tribe and males (p0.05. In conclusion, there is no significant correlation between interalar width and intercommisural width against mesiodistal incisor centralis maxilla width in a group of Buginese tribe. Interalar width and intercommisural width directly proportional to mesiodistal incisor centralis maxilla in a group of Buginese tribe. Interalar width and intercommisural width inversely proportional to mesiodistal incisor centralis maxilla in males and directly
Biological width: No violation zone
Ashu Sharma
2012-01-01
Full Text Available Maintenance of gingival health is one of the keys for the longevity of teeth, as well as for the longevity of restorations. The concept of Biologic width has been widely described by periodontists and restorative dentists. An adequate understanding of relationship between periodontal tissues and restorative dentistry is paramount to ensure adequate form, function and esthetics, and comfort of the dentition. While most clinicians are aware of this important relationship, uncertainty remains regarding specific concepts such as biologic width and indications and applications of surgical crown lengthening. These violations lead to complications like gingival inflammation, alveolar bone loss and improper fit of the restorative component. This review gives the wide aspect of the complex question of biologic width and represents an attempt to answer some of the demands in relation to it. The article also discusses the possible methods to assess biologic width, problems that occur after improper margin placement in the periodontium and the alternative procedures for prevention of biological width violation.
Resonant magnetic properties of gadolinium-gallium garnet single crystals
Bedyukh, A. R.; Danilov, V. V.; Nechiporuk, A. Yu.; Romanyuk, V. F.
1999-03-01
The results of experimental investigations of resonant magnetic properties of gadolinium-gallium garnet (GGG) single crystals at temperatures 4.2-300 K in the frequency range 1.6-9.3 GHz are considered. It is found that magnetic losses in GGG are determined by the initial splitting of energy levels for gadolinium ions in the garnet crystal lattice and by the dipole broadening. The width and shape of the electron paramagnetic resonance (EPR) line in the GGG crystal, whose asymmetry is manifested most strongly at low frequencies, can be explained by the influence of these factors. Magnetic losses in GGG increase with frequency and upon cooling. It is found that the EPR linewidth increases considerably with decreasing temperature due to the presence of rapidly relaxing impurities.
Dipoles, unintentional antennas and EMC
Berend Danker
2008-01-01
Full Text Available Radiated emissions from equipment commonly originate from electronic circuits that act as electric dipoles created by the signal voltage between the signal conductors or as magnetic dipoles formed by the signal current flowing in a loop. Direct emission is mostly small, but circuits often couple to long conductors or large wiring loops which act as antennas and are efficient radiators. A comparable situation exists when short dipole antennas or small wiring loops receive ambient noise (susceptibility. Usually the amplitude of noise sources or the susceptibility of circuits is an invariable. The dipole strength increases with the distance between the conductors and the area. Shielding and proper grounding decreases the interaction via unintentional antennas. Short-circuiting and the insertion of lossy ferrite cores reduce the efficiency of unintentional antennas.
Synchronization of interacting quantum dipoles
Zhu, B.; Schachenmayer, J.; Xu, M.; Herrera, F.; Restrepo, J. G.; Holland, M. J.; Rey, A. M.
2015-08-01
Macroscopic ensembles of radiating dipoles are ubiquitous in the physical and natural sciences. In the classical limit the dipoles can be described as damped-driven oscillators, which are able to spontaneously synchronize and collectively lock their phases in the presence of nonlinear coupling. Here we investigate the corresponding phenomenon with arrays of quantized two-level systems coupled via long-range and anisotropic dipolar interactions. Our calculations demonstrate that by incoherently driving dense packed arrays of strongly interacting dipoles, the dipoles can overcome the decoherence induced by quantum fluctuations and inhomogeneous coupling and reach a synchronized steady-state characterized by a macroscopic phase coherence. This steady-state bears much similarity to that observed in classical systems, and yet also exhibits genuine quantum properties such as quantum correlations and quantum phase diffusion (reminiscent of lasing). Our predictions could be relevant for the development of better atomic clocks and a variety of noise tolerant quantum devices.
Quantum optical dipole radiation fields
Stokes, Adam
2016-01-01
We introduce quantum optical dipole radiation fields defined in terms of photon creation and annihilation operators. These fields are identified through their spatial dependence, as the components of the total fields that survive infinitely far from the dipole source. We use these radiation fields to perturbatively evaluate the electromagnetic radiated energy-flux of the excited dipole. Our results indicate that the standard interpretation of a bare atom surrounded by a localised virtual photon cloud, is difficult to sustain, because the radiated energy-flux surviving infinitely far from the source contains virtual contributions. It follows that there is a clear distinction to be made between a radiative photon defined in terms of the radiation fields, and a real photon, whose identification depends on whether or not a given process conserves the free energy. This free energy is represented by the difference between the total dipole-field Hamiltonian and its interaction component.
Carvalho, Catarina; MarkoviÄ, Petar; Maróti, Miklós
2007-01-01
We prove that the constraint languages invariant under a short sequence of J\\'onsson terms (containing at most three non-trivial ternary terms) are tractable by showing that they have bounded width. This improves the previous result by Kiss and Valeriote and presents some evidence that the Larose-Zadori conjecture holds in the congruence-distributive case.
Finite-width plasmonic waveguides with hyperbolic multilayer cladding
Babicheva, Viktoriia; Shalaginov, Mikhail Y.; Ishii, Satoshi;
2015-01-01
Engineering plasmonic metamaterials with anisotropic optical dispersion enables us to tailor the properties of metamaterial-based waveguides. We investigate plasmonic waveguides with dielectric cores and multilayer metal-dielectric claddings with hyperbolic dispersion. Without using any homogeniz......Engineering plasmonic metamaterials with anisotropic optical dispersion enables us to tailor the properties of metamaterial-based waveguides. We investigate plasmonic waveguides with dielectric cores and multilayer metal-dielectric claddings with hyperbolic dispersion. Without using any...... homogenization, we calculate the resonant eigenmodes of the finite-width cladding layers, and find agreement with the resonant features in the dispersion of the cladded waveguides. We show that at the resonant widths, the propagating modes of the waveguides are coupled to the cladding eigenmodes and hence...
Planar Resonators for Metamaterials
M. Blaha
2012-09-01
Full Text Available This paper presents the results of an investigation into a combination of electric and magnetic planar resonators in order to design the building element of a volumetric metamaterial showing simultaneously negative electric and magnetic polarizabilities under irradiation by an electromagnetic wave. Two combinations of particular planar resonators are taken into consideration. These planar resonators are an electric dipole, a split ring resonator and a double H-shaped resonator. The response of the single resonant particle composed of a resonator with an electric response and a resonator with a magnetic response is strongly anisotropic. Proper spatial arrangement of these particles can make the response isotropic. This is obtained by proper placement of six planar resonators on the surface of a cube that now represents a metamaterial unit cell. The cells are distributed in space with 3D periodicity.
Low-lying dipole strengths of {sup 50}Cr
Pai, H.; Beck, T.; Beller, J.; Gayer, U.; Mertes, L.; Pietralla, N.; Ries, P.; Romig, C.; Werner, V.; Zweidinger, M. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany)
2015-07-01
Low-lying electric and magnetic dipole strengths (E1 and M1, respectively), particularly Pygmy Dipole Resonance (PDR) and Spin-flip M1 excitations, of atomic nuclei have drawn considerable attention in the last decade. The low-lying dipole strengths of {sup 50}Cr were studied with the method of nuclear resonance fluorescence up to 9.7 MeV, using bremsstrahlung provided by the superconducting Darmstadt electron linear accelerator S-DALINAC. Twenty-four spin-1 states were observed between 3.0 and 9.7 MeV excitation energy, 17 of those for the first time. The excited states' parities are determined through polarized photon scattering at the High Intensity gamma ray Source (HIγS), Triangle Universities Nuclear Laboratory (TUNL) in Durham, NC, USA. Microscopic calculations within the quasiparticle-phonon nuclear model are performed to interpret the dipole strength distribution of {sup 50}Cr. The experimental results of {sup 50}Cr are compared to data on its closed-shell N=28 isotone {sup 52}Cr and may provide information on the onset of the PDR in atomic nuclei.
Coherent manipulation of two dipole-dipole interacting ions
Beige, A; Knight, P L; Plenio, M B; Thompson, R C
2000-01-01
We investigate to what extent two trapped ions can be manipulated coherently when their coupling is mediated by a dipole-dipole interaction. We will show how the resulting level shift induced by this interaction can be used to create entanglement, while the decay of the states remains nearly negligible. This will allow us to implement conditional dynamics (a CNOT gate) and single qubit operations. We propose two different experimental realisations where a large level shift can be achieved and discuss both the strengths and weaknesses of this scheme from the point of view of a practical realization.
Novel Electrically Small Spherical Electric Dipole Antenna
Kim, Oleksiy S.
2010-01-01
of 72 ohms is numerically investigated and its performance is compared to that of the multiarm spherical helix antenna of the same size. Both antennas yield equal quality factors, which are about 1.5 times the Chu lower bound, but quite different cross-polarization characteristics.......This paper introduces a novel electrically small spherical meander antenna. Horizontal sections of the meander are composed of wire loops, radii of which are chosen so that the whole structure is conformal to a sphere of radius a. To form the meander the loops are connected by wires at a meridian...... plane. The antenna operates as an electric dipole, i.e. it radiates the TM10 spherical mode. The antenna is self-resonant and can be matched to a wide range of input feed lines without an external matching network. In this paper, a spherical meander antenna of the size ka = 0.27 and the input impedance...
Hybrid Exotic Meson Decay Width
Cook, M S
2005-01-01
We present results of a decay width calculation for a hybrid exotic meson(h, JPC=1-+) in the decay channel h to pi+a1. This calculation uses quenched lattice QCD and Luescher's finite box method. Operators for the h and pi+a1 states are used in a correlation matrix which was expanded by varying the smearing and fuzzing levels at source and sink points. Scattering phase shifts for a discrete set of relative pi+a1 momenta are determined using eigenvalues of the correlation matrix and formulae derived by Luescher. The phase shift data is very sparse, but fits to a Breit-Wigner model are made, resulting in a decay width of about 80 MeV.
Salvio, Alberto; Strumia, Alessandro; Urbano, Alfredo
2016-01-01
Motivated by the 750 GeV diphoton excess found at LHC, we compute the maximal width into $\\gamma\\gamma$ that a neutral scalar can acquire through a loop of charged fermions or scalars as function of the maximal scale at which the theory holds, taking into account vacuum (meta)stability bounds. We show how an extra gauge symmetry can qualitatively weaken such bounds, and explore collider probes and connections with Dark Matter.
Electromagnetic Design of Superconducting Dipoles Based on Sector Coils
Todesco, Ezio
2007-01-01
We study the coil lay-outs of superconducting dipoles for particle accelerators based on the sector geometry. We show that a simple model based on a sector coil with a wedge allows us to derive an equation giving the short sample field as a function of the aperture, coil width, cable properties and superconducting material. The equation agrees well with the actual results of several dipole coils that have been built in the last 30 years. The improvements due to the grading technique and the iron yoke are also studied. The proposed equation can be used as a benchmark to judge the efficiency of the coil design, and to carry out a global optimization of an accelerator lay-out.
1974-01-01
Stacks of SPS Dipole Magnets ready for installation in the tunnel. The SPS uses a separated function lattice with dipoles for bending and quadrupoles for focusing. The 6.2 m long normal conducting dipoles are of H-type with coils that are bent-up at the ends. There are two types, B1 (total of 360) and B2 (384). Both are for a maximum field of 1.8 Tesla and have the same outer dimensions (450x800 mm2 vxh) but with different gaps (B1: 39x129 mm2, B2: 52x92 mm2) tailored to the beam size. The yoke, made of 1.5 mm thick laminations, consists of an upper and a lower half joined together in the median plane once the coils have been inserted.
Synchronization of Interacting Quantum Dipoles
Zhu, Bihui; Xu, Minghui; Urbina, Felipe H; Restrepo, Juan G; Holland, Murray J; Rey, Ana Maria
2015-01-01
Macroscopic ensembles of radiating dipoles are ubiquitous in the physical and natural sciences. In the classical limit the dipoles can be described as damped-driven oscillators, which are able to spontaneously synchronize and collectively lock their phases. Here we investigate the correspond- ing phenomenon in the quantum regime with arrays of quantized two-level systems coupled via long-range and anisotropic dipolar interactions. Our calculations demonstrate that the dipoles may overcome the decoherence induced by quantum fluctuations and inhomogeneous couplings and evolve to a synchronized steady-state. This steady-state bears much similarity to that observed in classical systems, and yet also exhibits genuine quantum properties such as quantum correlations and quan- tum phase diffusion (reminiscent of lasing). Our predictions could be relevant for the development of better atomic clocks and a variety of noise tolerant quantum devices.
Emittance-Conserving Transverse Excitation using the "AC-Dipole" Principle.
Berrig, O E; Jones, R; Koopman, J; Koutchouk, Jean-Pierre; Schmidt, F; CERN. Geneva. SPS and LEP Division
2000-01-01
The so-called "AC-Dipole" principle allows the excitation of transverse oscillations to large (several sigma) excursions without emittance blow-up. The idea was originally proposed and tested at BNL for resonance crossing with polarised beams, using an orbit corrector dipole with an excitation frequency close to the betatron tune, hence "AC-Dipole". This method of beam excitation has several potential applications in the LHC, such as phase advance and beta measurements, dynamic aperture studies and the investigation of resonant driving terms. The technique was recently tested in the CERN SPS using the transverse damper as an "AC-Dipole" providing the fixed frequency excitation. Results from this experiment are presented, along with a brief explanation of the underlying principle.
Analyses of a Dipole Antenna Loaded by a Cylindrical Shell of Double Negative (DNG Metamaterial
Khan M. Z. Shams
2007-01-01
Full Text Available The current distribution, input impedance, and radiation pattern of a cylindrical dipole antenna enclosed by a thin cylindrical shell of double negative (DNG metamaterial are computed using the piecewise sinusoidal Galerkin formulation. In the presence of the DNG shell, the dipole antenna exhibits three interesting characteristics. The input impedance shows potentials for wide bandwidth due to the relative insensitivity of the impedance with frequency. Within specific ranges of DNG material parameter values, the dipole shows resonance at much lower frequencies than its resonant frequency in free space. The dipole does not show change in the direction of the principal beam nor does it show signs of beam splitting and side lobes even when the antenna length approaches one and a half wavelength.
Reduced neutron widths in the nuclear data ensemble: Experiment and theory do not agree
Koehler, P E
2010-01-01
I have analyzed reduced neutron widths ($\\Gamma_{n}^{0}$) for the subset of 1245 resonances in the nuclear data ensemble (NDE) for which they have been reported. Random matrix theory (RMT) predicts for the Gaussian orthogonal ensemble (GOE) that these widths should follow a $\\chi ^{2}$ distribution having one degree of freedom ($\
Dipole response of neutron-rich Sn isotopes
Klimkiewicz, A.; Adrich, P.; Boretzky, K.; Fallot, M.; Aumann, T.; Cortina-Gil, D.; Datta Pramanik, U.; Elze, Th. W.; Emling, H.; Geissel, H.; Hellstroem, M.; Jones, K. L.; Kratz, J. V.; Kulessa, R.; Leifels, Y.; Nociforo, C.; Palit, R.; Simon, H.; Surowka, G.; Sümmerer, K.; Typel, S.; Walus, W.
2007-05-01
The neutron-rich isotopes 129-133Sn were studied in a Coulomb excitation experiment at about 500 AMeV using the FRS-LAND setup at GSI. From the exclusive measurement of all projectile-like particles following the excitation and decay of the projectile in a high-Z target, the energy differential cross section can be extracted. At these beam energies dipole transitions are dominating, and within the semi-classical approach the Coulomb excitation cross sections can be transformed into photoabsorption cross sections. In contrast to stable Sn nuclei, a substantial fraction of dipole strength is observed at energies below the giant dipole resonance (GDR). For 130Sn and 132Sn this strength is located in a peak-like structure around 10 MeV excitation energy and exhibits a few percent of the Thomas-Reiche Kuhn (TRK) sum-rule strength. Several calculations predict the appearance of dipole strength at low excitation energies in neutron-rich nuclei. This low-lying strength is often referred to as pygmy dipole resonance (PDR) and, in a macroscopic picture, is discussed in terms of a collective oscillation of excess neutrons versus the core nucleons. Moreover, a sharp rise is observed at the neutron separation threshold around 5 MeV for the odd isotopes. A possible contribution of 'threshold strength', which can be described within the direct-breakup model is discussed. The results for the neutron-rich Sn isotopes are confronted with results on stable nuclei investigated in experiments using real photons.
Spreading widths of doorway states
De Pace, A., E-mail: depace@to.infn.i [Istituto Nazionale di Fisica Nucleare, Sezione di Torino, via P. Giuria 1, I-10125 Torino (Italy); Molinari, A. [Dipartimento di Fisica Teorica dell' Universita di Torino, via P. Giuria 1, I-10125 Torino (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Torino, via P. Giuria 1, I-10125 Torino (Italy); Weidenmueller, H.A. [Max-Planck-Institut fuer Kernphysik, D-69029 Heidelberg (Germany)
2011-01-01
As a function of energy E, the average doorway strength function S(E)-bar of a doorway state is commonly assumed to be Lorentzian in shape and characterized by two parameters, the peak energy E{sub 0} and the spreading width {Gamma}{sup {down_arrow}}. The simple picture is modified when the density of background states that couple to the doorway state changes significantly in an energy interval of size {Gamma}{sup {down_arrow}}. For that case we derive an approximate analytical expression for S(E)-bar. We test our result successfully against numerical simulations. Our result may have important implications for shell-model calculations.
N-Widths and Average Widths of Besov Classes in Sobolev Spaces
Gui Qiao XU; Yong Sheng SUN; Yong Ping LIU
2006-01-01
In this paper, we consider the n-widths and average widths of Besov classes in the usual Sobolev spaces. The weak asymptotic results concerning the Kolmogorov n-widths, the linear n-widths,the Gel'fand n-widths, in the Sobolev spaces on Td, and the infinite-dimensional widths and the average widths in the Sobolev spaces on Rd are obtained, respectively.
Entangling Dipole-Dipole Interactions for Quantum Logic in Optical Lattices
Deutsch, Ivan
2000-06-01
The ability to engineer the quantum state of a many-body system represents the ``holy grail" of coherent control and opens the door to a host of new applications and fundamental studies ranging from improvements in precision measurement to quantum computation. At the heart of these quantum-information processing tasks are entangled states. These can be created through a ``quantum-circuit" consisting of a series of simple quantum logic gates acting only on single or pairs of qubits. Any physical implementation of a quantum circuit must contend with an inherent conflict. Qubits must strongly couple to one another and to an external classical field which drives the algorithm, while simultaneously coupling very weakly to the noisy environment which decoheres the quantum superpositions. We have identified a new system for quantum-information processing: ultra-cold trapped neutral atoms (G. K. Brennen et al. ), Phys. Rev. Lett. 82 , 1060 (1999); see also eprint quant- ph/9910031. Neutrals interact very weakly with the environment and coupling between them can be induced on demand through resonant excitation or elastic collisions via direct overlap between wavepackets(D. Jaksch et al.), Phys. Rev. Lett. 82 1975 (1999).. The ability to turn interactions on and off reduces decoherence and the spread of errors amongst qubits. In the implementation presented here I will discuss entangling atoms with electric dipole-dipole interactions in optical lattices (P.S. Jessen and I. H. Deutsch, Adv. At. Mol. Phys. 36), 91 (1996).. These traps provide an extremely flexible environment for coherent control of both internal and external degrees of freedom of atom wave packets as in ion traps(D. Wineland et al.), Fortschr. Phys. 46, 363 (1998).. Dipole-dipole interactions can be coherent when atoms are tightly localized at a distance small compared to the optical wavelength. By inducing dipoles conditional on the logical state of the atoms we can engineer quantum gates. Detailed analysis
Searching for electric dipole moments
Jungmann, Klaus
2013-01-01
Searches for a permanent Electric Dipole Moment (EDM) of a fundamental particle provide a wide window for the discovery of potential New Physics. Within todays Standard Model in particle physics the well established violation of CP symmetry gives rise to EDMs which are several orders of magnitude be
Particle electric dipole-moments
Pendlebury, J.M. [Sussex Univ., Brighton (United Kingdom)
1997-04-01
The incentive to detect particle electric dipole-moments, as a window on time-reversal violation, remains undiminished. Efforts to improve the measurements for the neutron, the electron and some nuclei are still making rapid progress as more powerful experimental methods are brought to bear. A new measurement for the neutron at ILL is presented. (author). 7 refs.
Schildknecht, Dieter
2016-01-01
We give a brief representation of the theoretical results from the color dipole picture, covering the total photoabsorption cross section, high-energy $J/\\psi$ photoproduction with respect to recent experimental data from the LHCb Collaboration at CERN, and ultra-high energy neutrino scattering, relevant for the ICE-CUBE experiment.
Andersen, Jørgen Bach
2006-01-01
A number of antenna topics may be treated by studying just two parallel, closely spaced electrical dipoles. They form an array and they may be coupled to form a single antenna with one port, or coupled through a coupling network to form a multiport antenna. The situations discussed are the creation...
Interatomic Coulombic decay widths of helium trimer: Ab initio calculations
Kolorenč, Přemysl, E-mail: kolorenc@mbox.troja.mff.cuni.cz [Charles University in Prague, Faculty of Mathematics and Physics, Institute of Theoretical Physics, V Holešovičkách 2, 180 00 Prague (Czech Republic); Sisourat, Nicolas [Sorbonne Universités, UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique Matière et Rayonnement, F-75005 Paris (France); CNRS, UMR 7614, Laboratoire de Chimie Physique Matière et Rayonnement, F-75005 Paris (France)
2015-12-14
We report on an extensive study of interatomic Coulombic decay (ICD) widths in helium trimer computed using a fully ab initio method based on the Fano theory of resonances. Algebraic diagrammatic construction for one-particle Green’s function is utilized for the solution of the many-electron problem. An advanced and universal approach to partitioning of the configuration space into discrete states and continuum subspaces is described and employed. Total decay widths are presented for all ICD-active states of the trimer characterized by one-site ionization and additional excitation of an electron into the second shell. Selected partial decay widths are analyzed in detail, showing how three-body effects can qualitatively change the character of certain relaxation transitions. Previously unreported type of three-electron decay processes is identified in one class of the metastable states.
Structural analysis of a dipole system in two-dimensional channels.
Haghgooie, Ramin; Doyle, Patrick S
2004-12-01
A system of magnetic dipoles in two-dimensional (2D) channels was studied using Brownian dynamics simulations. The dipoles interact with a purely repulsive r(-3) potential and are confined by two hard walls in one of the dimensions. Solid crystals were annealed in the 2D channels and the structural properties of the crystals were investigated. The long-ranged nature of the purely repulsive dipoles combined with the presence of hard walls led to structural deviations from the unbounded (infinite) 2D dipolar crystal. The structures in the channels were characterized by a high density of particles along the walls. The particles along the wall became increasingly localized as the channel width was increased. The spacing of the walls was important in determining the properties of the structures formed in the channel. Small changes in the width of the channel induced significant structural changes in the crystal. These structural changes were manifested in the density profiles, defect concentrations, and local bond-orientation order of the system. Oscillations in the structural properties were observed as the channel width was increased, indicating the existence of magic-number channel widths for this system. As the channel width was increased the properties of the confined system approached those of the unbounded system surprisingly slowly.
Multiphonon giant resonances in nuclei
Aumann, T. [Mainz Univ. (Germany). Inst. fuer Kernchemie; Bortignon, P.F. [Milan Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Milan (Italy); Emling, H. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)
1998-07-01
We review the present knowledge of multiphonon giant resonances in nuclei. Theoretical concepts approaching the intrinsic structure and excitation mechanisms of multi-phonon states are discussed. The available experimental results are summarized, including a brief description of applied techniques. This review emphasizes electromagnetic excitations of double dipole resonances. Open questions and possible routes toward a solution are addressed. (orig.)
Measurement of effective sheath width around the cutoff probe based on electromagnetic simulation
Kim, D. W.; Oh, W. Y., E-mail: sjyou@cnu.ac.kr, E-mail: woh1@kaist.ac.kr [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); You, S. J., E-mail: sjyou@cnu.ac.kr, E-mail: woh1@kaist.ac.kr [Department of Physics, Chungnam National University, Daejeon 305-701 (Korea, Republic of); Kim, J. H. [Center for Vacuum Technology, Korea Research Institute of Standards and Science, Daejeon 305-306 (Korea, Republic of); Chang, H. Y. [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Yoon, J.-S. [Plasma Technology Research Center, National Fusion Research Institute, Gunsan 573-540 (Korea, Republic of)
2016-05-15
We inferred the effective sheath width using the cutoff probe and incorporating a full-wave three-dimensional electromagnetic (EM) simulation. The EM simulation reproduced the experimentally obtained plasma-sheath resonance (PSR) on the microwave transmission (S{sub 21}) spectrum well. The PSR frequency has a one-to-one correspondence with the width of the vacuum layer assumed to be the effective sheath in the EM simulation model. The sheath width was estimated by matching the S{sub 21} spectra of the experiment and the EM simulation for different widths of the sheath. We found that the inferred sheath widths quantitatively and qualitatively agree with the sheath width measured by incorporating an equivalent circuit model. These results demonstrate the excellent potential of the cutoff probe for inferring the effective sheath width from its experimental spectrum data.
Average radiation widths of levels in natural xenon isotopes
Noguere, G., E-mail: gilles.noguere@cea.fr [CEA, DEN, Cadarache, F-13108 Saint Paul les Durance (France); Litaize, O.; Archier, P.; De Saint Jean, C. [CEA, DEN, Cadarache, F-13108 Saint Paul les Durance (France); Mutti, P. [Institut Laue-Langevin, F-38042 Grenoble (France)
2011-11-15
Average radiation widths <{Gamma}{sub {gamma}>} for the stable xenon isotopes have been estimated using neutron resonance spectroscopic information deduced from high-resolution capture and transmission data measured at the electron linear accelerator GELINA of the Institute for Reference Materials and Measurements (IRMM) in Geel, Belgium. The combination of conventional Neutron Resonance Shape Analysis techniques (NRSA) with high-energy model calculations in a simple Bayesian learning method permit to calculate a consistent local systematic in the xenon's mass region (Z=54) from A=124 to A=136.
Wu, Yunqiu; Arslanagic, Samel
The resonant/anti-resonant behavior of parameters extracted by the S-parameter method for two-dimensional epsilon-, mu- and double-negative (ENG, MNG, DNG) materials is investigated. The unit cells consist of infinite dielectric cylinders supporting electric dipole, magnetic dipole, or both....... It is shown that the extraction procedure yields one resonant material parameter, and one anti-resonant material parameter in MNG and ENG configurations. However, both parameters display an over-all resonant response in DNG configurations where electric and magnetic dipole modes are excited simultaneously....
Refutation of stability proofs for dipole vortices
Nycander, J.
1992-01-01
Five stability proofs for dipole vortices (modons) that have been presented by various authors are examined. It is shown that they are all incorrect, and that westward-propagating dipoles are in fact unstable, in contradiction to some of the proofs.......Five stability proofs for dipole vortices (modons) that have been presented by various authors are examined. It is shown that they are all incorrect, and that westward-propagating dipoles are in fact unstable, in contradiction to some of the proofs....
Soft Dipole Modes of Neutron-Rich Nuclei
Csoto, A.; Gibson, B. F.; Afnan, I. R.
1996-10-01
We explore the open question of whether valance neutrons in ``halo nuclei'' can oscillate against the core to create a ``soft dipole'' mode. It has been suggested that such a dipole state would be situated at a few MeV of excitation energy, in contrast to usual dipole excitations at higher energies. The existence of a soft dipole mode, at least in ^11Li, appears to be supported by certain theoretical models and experimental data.footnote A. C. Hayes, Comments in Nuclear and Particle Physics 22, 27 (1996) However, this conclusion is based upon the behavior of specific observables at real energies. To clearly establish the existence of such resonant states, one should locate the corresponding complex poles of the S-matrix. We study ^6He and ^11Li in a three-body model based upon separable potentials that describe the known physics of the underlying two-body interactions. We solve the resulting Faddeev equations, continued into the complex energy plane, to search for the low lying excited states of these neutron-rich light nuclei.
Noncommutative Dipole Field Theories And Unitarity
Chiou, D W; Chiou, Dah-Wei; Ganor, Ori J.
2004-01-01
We extend the argument of Gomis and Mehen for violation of unitarity in field theories with space-time noncommutativity to dipole field theories. In dipole field theories with a timelike dipole vector, we present 1-loop amplitudes that violate the optical theorem. A quantum mechanical system with nonlocal potential of finite extent in time also shows violation of unitarity.
Perturbative Odderon in the Dipole Model
Kovchegov, Yu V; Wallon, S; Kovchegov, Yuri V.; Szymanowski, Lech; Wallon, Samuel
2003-01-01
We show that, in the framework of Mueller's dipole model, the perturbative QCD odderon is described by the dipole model equivalent of the BFKL equation with a $C$-odd initial condition. The eigenfunctions and eigenvalues of the odderon solution are the same as for the dipole BFKL equation and are given by the functions $E^{n,\
Critical behavior of isotropic three-dimensional systems with dipole-dipole interactions
Belim, S. M., E-mail: sbelim@mail.ru [Dostoevsky Omsk State University (Russian Federation)
2013-06-15
The critical behavior of Heisenberg magnets with dipole-dipole interactions near the line of second-order phase transitions directly in three-dimensional space is investigated in terms of a field-theoretic approach. The dependences of critical exponents on the dipole-dipole interaction parameter are derived. Comparison with experimental facts is made.
Technology of superconducting accelerator dipoles
Hassenzahl, W.V.; Meuser, R.B.; Taylor, C.
1983-06-01
We discuss accelerator dipoles and their characteristics. Other types of magnets, in particular bubble chamber magnets have been quite successful. Their performance is based on cryogenic stability which is addressed only briefly in this chapter. This type of stability is not available to the accelerator designer because of the large quantities of copper or other stabilizer that would reduce the current density in the windings to an unacceptably low value.
Radiating dipoles in photonic crystals
Busch, Kurt; Vats, Nipun; John, Sajeev; Sanders, Barry C.
2000-01-01
The radiation dynamics of a dipole antenna embedded in a Photonic Crystal are modeled by an initially excited harmonic oscillator coupled to a non--Markovian bath of harmonic oscillators representing the colored electromagnetic vacuum within the crystal. Realistic coupling constants based on the natural modes of the Photonic Crystal, i.e., Bloch waves and their associated dispersion relation, are derived. For simple model systems, well-known results such as decay times and emission spectra ar...
Electron Dipole-Dipole ESEEM in Field-Step ELDOR of Nitroxide Biradicals
Kulik, L. V.; Grishin, Yu. A.; Dzuba, S. A.; Grigoryev, I. A.; Klyatskaya, S. V.; Vasilevsky, S. F.; Tsvetkov, Yu. D.
2002-07-01
The use of a rapid stepping of the magnetic field for investigation of electron dipole-dipole ESEEM in pulsed X-band ELDOR is described. The magnetic field jump, synchronized with a microwave pumping pulse, is positioned between the second and the third pulses of the stimulated echo pulse sequence. This echo is measured as a function of the delay between the first and the second pulses. The data are analyzed for a Fourier transform resulting in a Pake resonance pattern. To remove the electron-nuclear contributions to ESEEM, time traces with pumping were divided by those without. This resulted in complete elimination of electron-nuclear contributions, which is seen from the absence of peaks at nuclear frequencies and the similarity of results for protonated and deuterated solvents. For increasing the electron-electron modulation depth, a scanning of the magnetic field during the microwave pumping is proposed. The interspin distances and their distribution are determined for two long-chained (ca. 2 nm) nitroxide biradicals in glassy toluene and in frozen nematic liquid crystal 4-cyano-4'-pentyl-biphenyl. For the latter solvent, the alignment of the axis connecting two nitroxides in biradicals is quantitatively analyzed.
2010-01-01
... Route width. (a) Routes and route segments over Federal airways, foreign airways, or advisory routes have a width equal to the designated width of those airways or advisory routes. Whenever the... clearance. (2) Minimum en route altitudes. (3) Ground and airborne navigation aids. (4) Air traffic density...
Clique-width of unit interval graphs
Lozin, Vadim V.
2007-01-01
The clique-width is known to be unbounded in the class of unit interval graphs. In this paper, we show that this is a minimal hereditary class of unbounded clique-width, i.e., in every hereditary subclass of unit interval graphs the clique-width is bounded by a constant.
Resonant metallic nanostructures for enhanced terahertz spectroscopy
Toma, A.
2015-11-12
We present our recent studies on terahertz resonant dipole nanoantennas. Exploiting the localization and enhancement capabilities of these devices, we introduce an effective method to perform terahertz spectroscopy on an extremely small number of nano-objects.
Monolayer patterning using ketone dipoles.
Kim, Min Kyoung; Xue, Yi; Pašková, Tereza; Zimmt, Matthew B
2013-08-14
The self-assembly of multi-component monolayers with designed patterns requires molecular recognition among components. Dipolar interactions have been found to influence morphologies of self-assembled monolayers and can affect molecular recognition functions. Ketone groups have large dipole moments (2.6 D) and are easily incorporated into molecules. The potential of ketone groups for dipolar patterning has been evaluated through synthesis of two 1,5-disubstituted anthracenes bearing mono-ketone side chains, STM characterization of monolayers self-assembled from their single and two component solutions and molecular mechanics simulations to determine their self-assembly energetics. The results reveal that (i) anthracenes bearing self-repulsive mono-ketone side chains assemble in an atypical monolayer morphology that establishes dipolar attraction, instead of repulsion, between ketones in adjacent side chains; (ii) pairs of anthracene molecules whose self-repulsive ketone side chains are dipolar complementary spontaneously assemble compositionally patterned monolayers, in which the two components segregate into neighboring, single component columns, driven by side chain dipolar interactions; (iii) compositionally patterned monolayers also assemble from dipolar complementary anthracene pairs that employ different dipolar groups (ketones or CF2 groups) in their side chains; (iv) the ketone group, with its larger dipole moment and size, provides comparable driving force for patterned monolayer formation to that of the smaller dipole, and smaller size, CF2 group.
Nonlinearity of the Dipole Moment Surface and Intensities Anomaly of CHCl3
LIN Hai; YUAN Lan-Feng; WANG Dong-Open; ZHU Qing-Shi
2000-01-01
Relative absorption intensities of the Fermi resonance polyads of isolated C-H chromophore for the CHCl3 molecule are calculated by one-dimensional dipole moment surface which had been obtained by the ab initio density functional method B3PW91 with 6-311++ G (3df, 2pd) basis set, and agrer very well with the experimental results.It is shown that the nonlinearity of the dipole moment surface in the vicinity of the equilibrium configuration is responsible for the intensities anomaly, i.e. the unusual strong intensities of the second Fermi resonance polyad.
Indirect Constraints on the Scalar Di-Photon Resonance at the LHC
Goertz, Florian; Katz, Andrey; Nardecchia, Marco
2016-01-01
Motivated by the tantalizing excesses recently reported in the di-photon invariant mass spectrum at the LHC, we scrutinize some implications of scalar di-photon resonances in high energy proton-proton collisions. In particular, indications of a large width impose several challenges for model building. We show how calculability and unitarity considerations severely limit possible perturbative realizations of such a signal and propose a simple criterion that can be adapted to any renormalizable model. Furthermore, we discuss correlations between a di-photon excess and precision observables, including the anomalous magnetic and electric dipole moments of quarks and leptons, neutral meson oscillations and radiative flavor changing neutral current mediated decays of heavy leptons and hadrons. We find that existing searches and measurements significantly constrain the possibilities for a scalar resonance decaying into final states involving Standard Model fermions. We propose future search strategies which could el...
Palindromic widths of nilpotent and wreath products
Valeriy G Bardakov; Oleg V Bryukhanov; Krishnendu Gongopadhyay
2017-02-01
We prove that the nilpotent product of a set of groups $A_1, \\ldots , A_s$ has finite palindromic width if and only if the palindromic widths of $A_i$, $i = 1, \\ldots , s$, are finite. We give a new proof that the commutator width of $F_n \\wr K$ is infinite, where $F_n$ is a free group of rank $n\\geq 2$ and $K$ is a finite group. This result, combining with a result of Fink [9] gives examples of groups with infinite commutator width but finite palindromic width with respect to some generating set.
Resonant interaction modified by the atomic environment
Sainz, I; Klimov, A B; Chumakov, S M [Departamento de Fisica, Universidad de Guadalajara, Revolucion 1500, 44410, Guadalajara, Jal. (Mexico)
2003-04-01
The dynamics of a resonant atom interacting with a quantum cavity field in the presence of many off-resonant atoms is studied. In the framework of the effective Hamiltonian approach we show that the results of elimination of non-resonant transitions are (a) a dynamical Stark shift of the field frequency, dependent on the populations of non-resonant atoms, (b) dependence of the coupling constant between the resonant atom and the field on the populations of non-resonant atoms, and (c) an effective dipole-dipole interaction between non-resonant atoms. Two effects (the coherent influence and dephasing) of the off-resonant environment on the dynamics of the resonant atom are discussed.
Single-resonator double-negative metamaterial
Warne, Larry K.; Basilio, Lorena I.; Langston, William L.; Johnson, William A.; Ihlefeld, Jon; Ginn, III, James C.; Clem, Paul G.; Sinclair, Michael B.
2016-06-21
Resonances can be tuned in dielectric resonators in order to construct single-resonator, negative-index metamaterials. For example, high-contrast inclusions in the form of metallic dipoles can be used to shift the first electric resonance down (in frequency) to the first magnetic resonance, or alternatively, air splits can be used to shift the first magnetic resonance up (in frequency) near the first electric resonance. Degenerate dielectric designs become especially useful in infrared- or visible-frequency applications where the resonator sizes associated with the lack of high-permittivity materials can become of sufficient size to enable propagation of higher-order lattice modes in the resulting medium.
Single-resonator double-negative metamaterial
Warne, Larry K.; Basilio, Lorena I.; Langston, William L.; Johnson, William A.; Ihlefeld, Jon; Ginn, III, James C.; Clem, Paul G.; Sinclair, Michael B.
2016-06-21
Resonances can be tuned in dielectric resonators in order to construct single-resonator, negative-index metamaterials. For example, high-contrast inclusions in the form of metallic dipoles can be used to shift the first electric resonance down (in frequency) to the first magnetic resonance, or alternatively, air splits can be used to shift the first magnetic resonance up (in frequency) near the first electric resonance. Degenerate dielectric designs become especially useful in infrared- or visible-frequency applications where the resonator sizes associated with the lack of high-permittivity materials can become of sufficient size to enable propagation of higher-order lattice modes in the resulting medium.
Lupo, P.; Haghshenasfard, Z.; Cottam, M. G.; Adeyeye, A. O.
2016-12-01
A systematic investigation is presented for the magnetization dynamics in trilayer nanowires, consisting of two permalloy (Ni80Fe20 ) layers separated by a nonmagnetic Ru spacer layer. The width of the wires ranges from 90 to 190 nm. By varying the Ru thickness between 0.7 and 2.0 nm, the interlayer coupling can be effectively controlled, modifying the corresponding magnetic ground state and the spin-wave dynamics. By contrast with previous work on coupled trilayer nanowires with larger widths (270 nm and more), the focus here is on nanowire arrays where the strong shape anisotropy competes with the Ruderman-Kittel-Kasuya-Yosida interactions and biquadratic exchange interactions across the Ru interface, as well as dipolar interactions and Zeeman energy. As a result, the spin-wave spectrum is found to be drastically modified. Ferromagnetic resonance and hysteresis loop measurements are reported over a wide range of applied magnetic fields, showing that the overall magnetization alignment between the permalloy layers may be parallel, antiparallel, or in a spin-flop state, depending on the overall interlayer coupling. The experimental results for different stripe widths are successfully analyzed using a microscopic dipole-dipole theory and micromagnetic simulations.
RHIC spin flipper AC dipole controller
Oddo, P.; Bai, M.; Dawson, C.; Gassner, D.; Harvey, M.; Hayes, T.; Mernick, K.; Minty, M.; Roser, T.; Severino, F.; Smith, K.
2011-03-28
The RHIC Spin Flipper's five high-Q AC dipoles which are driven by a swept frequency waveform require precise control of phase and amplitude during the sweep. This control is achieved using FPGA based feedback controllers. Multiple feedback loops are used to and dynamically tune the magnets. The current implementation and results will be presented. Work on a new spin flipper for RHIC (Relativistic Heavy Ion Collider) incorporating multiple dynamically tuned high-Q AC-dipoles has been developed for RHIC spin-physics experiments. A spin flipper is needed to cancel systematic errors by reversing the spin direction of the two colliding beams multiple times during a store. The spin flipper system consists of four DC-dipole magnets (spin rotators) and five AC-dipole magnets. Multiple AC-dipoles are needed to localize the driven coherent betatron oscillation inside the spin flipper. Operationally the AC-dipoles form two swept frequency bumps that minimize the effect of the AC-dipole dipoles outside of the spin flipper. Both AC bumps operate at the same frequency, but are phase shifted from each other. The AC-dipoles therefore require precise control over amplitude and phase making the implementation of the AC-dipole controller the central challenge.
Visualization of Distance Distribution from Pulsed Double Electron-Electron Resonance Data
Bowman, Michael K.; Maryasov, Alexander G.; Kim, Nak-Kyoon; DeRose, Victoria J.
2004-01-01
Double electron-electron resonance (DEER), also known as pulsed electron-electron double resonance (PELDOR), is a time-domain electron paramagnetic resonance method that can measure the weak dipole-dipole interactions between unpaired electrons. DEER has been applied to discrete pairs of free radicals in biological macromolecules and to clusters containing small numbers of free radicals in polymers and irradiated materials. The goal of such work is to determine the distance or distribution of distances between radicals, which is an underdetermined problem. That is, the spectrum of dipolar interactions can be readily calculated for any distribution of free radicals, but there are many, quite different distributions of radicals that could produce the same experimental dipolar spectrum. This paper describes two methods that are useful for approximating the distance distributions for the large subset of cases in which the mutual orientations of the free radicals are uncorrelated and the width of the distribution is more than a few percent of its mean. The first method relies on a coordinate transformation and is parameter free, while the second is based on iterative least-squares with Tikhonov regularization. Both methods are useful in DEER studies of spin labeled biomolecules containing more than two labels.
Collective Dipole-Dipole Interactions in an Atomic Array
Sutherland, R T
2016-01-01
The coherent dipole-dipole interactions of atoms in an atomic array are studied. It is found that the excitation probability of an atom in an array parallel to the direction of laser propagation ($\\boldsymbol{\\hat{k}}$) will either grow or decay logarithmically along $\\boldsymbol{\\hat{k}}$, depending on the detuning of the laser. The symmetry of the system for atomic separations of $\\delta r = j\\lambda/2$, where $j$ is an integer, causes the excitation distribution and scattered radiation to abruptly become symmetric about the center of the array. For atomic separations of $\\delta r < \\lambda/2$, the appearance of a collection of extremely subradiant states ($\\Gamma\\sim 0$), disrupts the described trend. In order to interpret the results from a finite array of atoms, a band structure calculation in the $N\\rightarrow \\infty$ limit is conducted where the decay rates and the Collective Lamb Shifts of the eigenmodes along the Brillouin zone are shown. Finally, the band structure of an array strongly affects it...
The sign of the dipole-dipole potential by axion exchange
Daido, Ryuji; Takahashi, Fuminobu
2017-09-01
We calculate a dipole-dipole potential between fermions mediated by a light pseudoscalar, axion, paying a particular attention to the overall sign. While the sign of the potential is physical and important for experiments to discover or constrain the axion coupling to fermions, there is often a sign error in the literature. The purpose of this short note is to clarify the sign issue of the axion-mediated dipole-dipole potential. As a by-product, we find a sign change of the dipole-dipole potenital due to the different spin of the mediating particle.
Dipole Moments of Methyl - Substituted Cyclohexanone
Ka, Soo Hyun; Kim, Ji Hyun; Oh, Jung Jin [Sookmyung Women' s University, Seoul (Korea, Republic of)
2011-01-15
The microwave spectrum of 3-methylcyclopentanone has been studied and the dipole components Ιμ{sub a}Ι = 2.97(2), Ιμ{sub b}Ι = 1.00(3), Ιμ{sub c}Ι = 0.18(5), and ΙμtotΙ = 3.14(3) D were reported. These were consistent with a twisted-ring conformation with a methyl group in the equatorial position. The conformation of 3-, 4-methyl cyclohexanone in its ground state has been reported to be a chair form with the methyl group in the equatorial position. The resonance enhanced multiphoton ionization (REMPI) method has been applied to methyl- and ethyl- derivatives of cyclohexanone to investigate the various conformers as well as cyclic ketone and cyclic ether including oxygen. The structural information was compared with ab initio density functional theory to calculate not only the structure of cyclohexanone, but the vibrational spectra of isotopomers of cyclohexanone as well. The information was compared with electron diffraction structure and liquid-phase IR spectra.
Plasmon coupling of magnetic resonances in an asymmetric gold semishell
Ye, Jian; Kong, Yan; Liu, Cheng
2016-05-01
The generation of magnetic dipole resonances in metallic nanostructures is of great importance for constructing near-zero or even negative refractive index metamaterials. Commonly, planar two-dimensional (2D) split-ring resonators or relevant structures are basic elements of metamaterials. In this work, we introduce a three-dimensional (3D) asymmetric Au semishell composed of two nanocups with a face-to-face geometry and demonstrate two distinct magnetic resonances spontaneously in the visible-near infrared optical wavelength regime. These two magnetic resonances are from constructive and destructive hybridization of magnetic dipoles of individual nanocups in the asymmetric semishell. In contrast, complete cancellation of magnetic dipoles in the symmetric semishell leads to only a pronounced electric mode with near-zero magnetic dipole moment. These 3D asymmetric resonators provide new ways for engineering hybrid resonant modes and ultra-high near-field enhancement for the design of 3D metamaterials.
Gammelmark, Søren; Zinner, Nikolaj Thomas
2013-01-01
We study polar molecules with long-range dipole-dipole interactions confined to move on a two-leg ladder for different orientations of the molecular dipole moments with respect to the ladder. Matrix product states are employed to calculate the many-body ground state of the system as function...... of lattice filling fractions, perpendicular hopping between the legs, and dipole interaction strength. We show that the system exhibits zig-zag ordering when the dipolar interactions are predominantly repulsive. As a function of dipole moment orientation with respect to the ladder, we find...... that there is a critical angle at which ordering disappears. This angle is slightly larger than the angle at which the dipoles are non-interacting along a single leg. This behavior should be observable using current experimental techniques....
Tulintseff, A. N.
1993-01-01
Printed dipole elements and their complement, linear slots, are elementary radiators that have found use in low-profile antenna arrays. Low-profile antenna arrays, in addition to their small size and low weight characteristics, offer the potential advantage of low-cost, high-volume production with easy integration with active integrated circuit components. The design of such arrays requires that the radiation and impedance characteristics of the radiating elements be known. The FDTD (Finite-Difference Time-Domain) method is a general, straight-forward implementation of Maxwell's equations and offers a relatively simple way of analyzing both printed dipole and slot elements. Investigated in this work is the application of the FDTD method to the analysis of printed dipole and slot elements transversely coupled to an infinite transmission line in a multilayered configuration. Such dipole and slot elements may be used in dipole and slot series-fed-type linear arrays, where element offsets and interelement line lengths are used to obtain the desired amplitude distribution and beam direction, respectively. The design of such arrays is achieved using transmission line theory with equivalent circuit models for the radiating elements. In an equivalent circuit model, the dipole represents a shunt impedance to the transmission line, where the impedance is a function of dipole offset, length, and width. Similarly, the slot represents a series impedance to the transmission line. The FDTD method is applied to single dipole and slot elements transversely coupled to an infinite microstrip line using a fixed rectangular grid with Mur's second order absorbing boundary conditions. Frequency-dependent circuit and scattering parameters are obtained by saving desired time-domain quantities and using the Fourier transform. A Gaussian pulse excitation is applied to the microstrip transmission line, where the resulting reflected signal due to the presence of the radiating element is used
LOG PERIODIC DIPOLE ARRAY WITH PARASITIC ELEMENTS
The design and measured characteristics of dipole and monopole versions of a log periodic array with parasitic elements are discussed. In a dipole...array with parasitic elements, these elements are used in place of every alternate dipole, thereby eliminating the need of a twisted feed arrangement...for the elements to obtain log periodic performance of the anntenna. This design with parasitic elements lends itself to a monopole version of the
Approximation Algorithms for Directed Width Parameters
Kintali, Shiva; Kumar, Akash
2011-01-01
Treewidth of an undirected graph measures how close the graph is to being a tree. Several problems that are NP-hard on general graphs are solvable in polynomial time on graphs with bounded treewidth. Motivated by the success of treewidth, several directed analogues of treewidth have been introduced to measure the similarity of a directed graph to a directed acyclic graph (DAG). Directed treewidth, D-width, DAG-width, Kelly-width and directed pathwidth are some such parameters. In this paper, we present the first approximation algorithms for all these five directed width parameters. For directed treewidth and D-width we achieve an approximation factor of O(sqrt{logn}). For DAG-width, Kelly-width and directed pathwidth we achieve an O({\\log}^{3/2}{n}) approximation factor. Our algorithms are constructive, i.e., they construct the decompositions associated with these parameters. The width of these decompositions are within the above mentioned factor of the corresponding optimal width.
Width Distributions for Convex Regular Polyhedra
Finch, Steven R
2011-01-01
The mean width is a measure on three-dimensional convex bodies that enjoys equal status with volume and surface area [Rota]. As the phrase suggests, it is the mean of a probability density f. We verify formulas for mean widths of the regular tetrahedron and the cube. Higher-order moments of f_tetra and f_cube have not been examined until now. Assume that each polyhedron has edges of unit length. We deduce that the mean square width of the regular tetrahedron is 1/3+(3+sqrt(3))/(3*pi) and the mean square width of the cube is 1+4/pi.
The width of 5-dimensional prismatoids
Matschke, Benjamin; Weibel, Christophe
2012-01-01
Santos' construction of counter-examples to the Hirsch conjecture is based on the existence of prismatoids of dimension d of width greater than d. The case d=5 being the smallest one in which this can possibly occur, we here study the width of 5-dimensional prismatoids, obtaining the following results: - There are 5-prismatoids of width six with only 25 vertices, versus the 48 vertices in Santos' original construction. This leads to lowering the dimension of the non-Hirsch polytopes from 43 to only 20. - There are 5-prismatoids with n vertices and width \\Omega(n^(1/2)) for arbitrarily large n.
The Inverse Problem for the Dipole Field
Epp, V
2015-01-01
The Inverse problem for an electromagnetic field produced by a dipole is solved. It is assumed that the field of an arbitrary changing dipole is known. Obtained formulae allow calculation of the position and dynamics of the dipole which produces the measured field. The derived results can be used in investigations on radiative process in solids caused by changing of the charge distribution. For example, generation of the electromagnetic field caused by oscillations of atoms or electron gas at the trace of a particle channeling in a crystal, or fields arising at solids cracking or dislocation formation -- in any case when one is interested in the details of the dipole field source.
Which dipole are you studying in lab?
Binder, P.-M.; Tate, Reuben B.; Crowder, Callie K.
2017-01-01
We explore the similarities and differences between the electric dipole studied in introductory physics and the purportedly equivalent elementary experiment in which the electric potential is measured on a conductive sheet as a current flows. The former is a three-dimensional electrostatic dipole while the latter is a two-dimensional steady-state dipole. In spite of these differences, and as shown in this work, the potentials due to these dipoles look very similar. This may be misleading to either students or unaware instructors.
Axion Induced Oscillating Electric Dipole Moments
Hill, Christopher T
2015-01-01
The axion electromagnetic anomaly induces an oscillating electric dipole for any static magnetic dipole. Static electric dipoles do not produce oscillating magnetic moments. This is a low energy theorem which is a consequence of the space-time dependent cosmic background field of the axion. The electron will acquire an oscillating electric dipole of frequency $m_a$ and strength $\\sim 10^{-32}$ e-cm, two orders of magnitude above the nucleon, and within four orders of magnitude of the present standard model DC limit. This may suggest sensitive new experimental venues for the axion dark matter search.
A SIZE-REDUCED LOG PERIODIC DIPOLE ANTENNA
Yang Zhengguang; Su Donglin; Lü Shanwei
2006-01-01
A rectangle capacity patch was adopted as the resonance unit of the Log Periodic Dipole Antenna (LPDA) so as to realize the miniaturization of this aerial in this paper. Fifteen rectangle capacity patch units of different parameters were analyzed in this paper and three design laws of size-reduction were found. According to these design laws, a 70% miniaturization ratio LPDA was designed and fabricated. The Voltage Standing Wave Ratio (VSWR) and pattern of the fabricated LPDA were measured. The results indicate that this size-reduction method do not deteriorate performance.
Theoretical study of the dipole moment of oxygen monofluoride (OF)
Langhoff, S. R.; Bauschlicher, C. W., Jr.; Partridge, H.
1983-01-01
The ground-state potential curve and dipole-moment function of OF are calculated theoretically using the complete active-space self-consistent-field levels, externally contracted configuration-interaction levels, or multireference (singles plus doubles) configuration-interaction levels. Both an extended Gaussian basis set and a double-zeta-plus-polarization basis set were applied. The results are presented in extensive tables and graphs. Best results are achieved using a large Gaussian basis set and taking the valence-correlation energy into account. It is suggested that OF may best be detected by its laser-magnetic-resonance spectrum in the IR.
Average Dissipative and Dipole Forces on a Three-Level Atom in a Laguerre-Gaussian Beam
WANG Zheng-Ling; YIN Jian-Ping
2005-01-01
@@ By means of the optical Bloch equations based on the atomic density matrix elements, the general expressions of the average dissipative force, dipole force and the mechanical torque acting on a A-configuration three-level atom in a linearly-polarized Laguerre-Gaussian beam (LGB) with an angular momentum of lh are derived, and the general properties of the average dissipative and dipole force on the three-level atom in the linearly-polarized LGB are analysed. We find a resonant property (with two resonant peaks) of the dissipative force and a non-resonant property (with two pairs of non-resonant peaks) of the dipole force on the three-level atom, which are completely different from those on the two-level atom. Our study also shows that all of general expressions on the three-level atom will be simplified to those on the two-level atom in the approximation of large detuning.
Simplified approach to double jumps for fluorescing dipole-dipole interacting atoms
Hannstein, V; Hannstein, Volker; Hegerfeldt, Gerhard C.
2006-01-01
A simplified scheme for the investigation of cooperative effects in the quantum jump statistics of small numbers of fluorescing atoms and ions in a trap is presented. It allows the analytic treatment of three dipole-dipole interacting four-level systems which model the relevant level scheme of Ba+ ions. For the latter, a huge rate of double and triple jumps was reported in a former experiment and the huge rate was attributed to the dipole-dipole interaction. Our theoretical results show that the effect of the dipole-dipole interaction on these rates is at most 5% and that for the parameter values of the experiment there is practically no effect. Consequently it seems that the dipole-dipole interaction can be ruled out as a possible explanation for the huge rates reported in the experiment.
Testing of a Single 11 T $Nb_3Sn$ Dipole Coil Using a Dipole Mirror Structure
Zlobin, Alexander [Fermilab; Andreev, Nicolai [Fermilab; Barzi, Emanuela [Fermilab; Chlachidze, Guram [Fermilab; Kashikhin, Vadim [Fermilab; Nobrega, Alfred [Fermilab; Novitski, Igor [Fermilab; Turrioni, Daniele [Fermilab; Karppinen, Mikko [CERN; Smekens, David [CERN
2014-07-01
FNAL and CERN are developing an 11 T Nb3Sn dipole suitable for installation in the LHC. To optimize coil design parameters and fabrication process and study coil performance, a series of 1 m long dipole coils is being fabricated. One of the short coils has been tested using a dipole mirror structure. This paper describes the dipole mirror magnetic and mechanical designs, and reports coil parameters and test results.
Pietralla, N. [Koeln Univ. (Germany). Inst. fuer Kernphysik; Beck, O. [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Besserer, J. [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Brentano, P. von [Koeln Univ. (Germany). Inst. fuer Kernphysik; Eckert, T. [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Fischer, R. [Koeln Univ. (Germany). Inst. fuer Kernphysik; Fransen, C. [Koeln Univ. (Germany). Inst. fuer Kernphysik; Herzberg, R.-D. [Koeln Univ. (Germany). Inst. fuer Kernphysik; Jaeger, D. [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Jolos, R.V. [Koeln Univ. (Germany). Inst. fuer Kernphysik]|[Bogoliubov Theoretical Laboratory, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Kneissl, U. [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Krischok, B. [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Margraf, J. [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Maser, H. [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Nord, A. [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Pitz, H.H. [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Rittner, M. [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Schiller, A. [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Zilges, A. [Koeln Univ. (Germany). Inst. fuer Kernphysik]|[WNSL, Yale University, P.O. Box 208124, New Haven, CT 06520-8124 (United States)
1997-05-26
Photon scattering experiments have been performed on the heavy deformed nuclei {sup 178,180}Hf using an E{sub {gamma}}<4 MeV bremsstrahlung beam as a continuous energy photon source. Numerous dipole excitations have been identified from the spectra of high-resolution Ge {gamma} detectors. Spins, K quantum numbers, dipole excitation strengths, and level widths, have been extracted from the scattering cross sections. From the measured level widths lifetimes of 67 levels can be deduced. The excitation strength of the scissor mode is discussed and extends the systematics from the neighboring rare earth nuclei. Besides the {Delta}K=1 excitations other dipole excitations have been observed that are distinguished from the scissor mode states by their different decay behavior. (orig.).
Silver nanodisks: optical properties study using the discrete dipole approximation method.
Brioude, A; Pileni, M P
2005-12-15
The simulated optical properties of silver nanodisks are presented. The extinction, absorption, and scattering efficiencies are calculated using the discrete dipole approximation. The influence of the nanodisk size, truncature (snip), aspect ratio, and environment on the plasmon resonance bands is investigated. In particular, the dipolar and multipolar resonance peak positions have been related to the specific features of the nanodisk geometry. An interpretation of the origins of each multipolar mode is proposed for the first time taking into account this geometry.
Christiansen, Peter Leth; Gaididei, Yuri Borisovich; Johansson, M.
1998-01-01
The dynamics of discrete two-dimensional nonlinear Schrodinger models with long-range dispersive interactions is investigated. In particular, we focus on the cases where the dispersion arises from a dipole-dipole interaction, assuming the dipole moments at each lattice site to be aligned either...
Dipole Engineering for Conducting Polymers
McClain, William Edward
A method for the growth of a TiO2 adhesion layer on PEDOT:PSS (poly[3,4- ethylenedioxythiophene]: poly[styrenesulfonate]) and for further functionalization with self-assembled monolayers of phosphonates (SAMPs) was developed. The TiO2 adhesion layer was grown via chemical vapor deposition using a titanium(IV) t-butoxide precursor, and was characterized by goniometry and X-ray photoelectron spectroscopy. TiO 2 grown on a model system, H-terminated silicon, indicated that the surface was t-butoxide terminated. Phenylphosphonic acids were synthesized with a variety of molecular dipoles and were used to change the work function of PEDOT:PSS through the formation of an aggregate surface dipole. Good correlation was found between the z-component of the molecular dipole and the change in work function, indicating that the film was well-ordered and dense. The magnitude of the changes in work function and goniometry measurements were similar to measurements on ITO, a substrate on which phosphonates form well-ordered monolayers. As-grown PEDOT:PSS/TiO 2 electrodes showed a lower work function compared to PEDOT:PSS, which is attributed to residual t-butoxide groups on the TiO 2 surface. UPS measurements revealed that reductions in work function in the modified electrodes lowered the difference in energy between the Fermi energy (EF) of the conducting polymer and the LUMO of PCBM ([6,6]-phenyl-C 61-butyric acid methyl ester). A reduction of this energy difference should translate into increased electron injection in electron-only diodes; however, devices with modified electrodes showed decreased current densities. UPS/IPES measurements show that TiO2 grown using this method has a much larger band gap than bulk or nanocrystalline TiO2, which is likely responsible for this decrease in device currents. At high bias, device currents increase dramatically, and the effects of the phosphonates or t-butoxide terminated TiO2 vanish. This is attributed to a reduction of the TiO2 to
Dipole Solitons in Nonlinear Media with an Exponential-Decay Nonlocal Response
YANG Zhen-Jun; MA Xue-Kai; ZHENG Yi-Zhou; GAO Xing-Hui; LU Da-Quan; HU Wei
2011-01-01
By applying the variational approach,the analytical expression of dipole solitons is obtained in nonlinear media with an exponential-decay nonlocal response.The relations of the soliton power versus the propagation constant and the soliton width are given.Some numerical simulations are carried out.The results show that the analytical expression is in excellent agreement with the numerical results for the strongly nonlocal case.
Berrig, O E; Jones, R; Koopman, J; Koutchouk, Jean-Pierre; Schmickler, Hermann; Schmidt, F
2001-01-01
The so-called "AC-Dipole" principle allows the excitation of transverse oscillations to large (several sigma) excursions without emittance blow-up. The idea was originally proposed and tested at BNL for resonance crossing with polarized beams, using an orbit corrector dipole with an excitation frequency close to the betatron tune, hence "AC-Dipole". This method of beam excitation has several potential applications in teh LHC, such as phase advance and beta-measurements, dynamic aperture studies and the investigation of resonance strengths. The technique was recently tested in the CERN SPS using the transverse damper as an "AC-Dipole" providing the fixed frequency excitation. Results from this experiment are presented, along with an explanation of the underlying principle.
2010-01-01
.... (a) Approved routes and route segments over U.S. Federal airways or foreign airways (and advisory... designated width of those airways or routes. Whenever the Administrator finds it necessary to determine the width of other approved routes, he considers the following: (1) Terrain clearance. (2) Minimum en route...
Constant Width Planar Computation Characterizes ACC0
Hansen, Kristoffer Arnsfelt
2006-01-01
We obtain a characterization of ACC0 in terms of a natural class of constant width circuits, namely in terms of constant width polynomial size planar circuits. This is shown via a characterization of the class of acyclic digraphs which can be embedded on a cylinder surface in such a way that all...
Constant Width Planar Computation Characterizes ACC0
Hansen, K.A.
2004-01-01
We obtain a characterization of ACC 0 in terms of a natural class of constant width circuits, namely in terms of constant width polynomial size planar circuits. This is shown via a characterization of the class of acyclic digraphs which can be embedded on a cylinder surface in such a way that all...
A Niche Width Model of Optimal Specialization
Bruggeman, Jeroen; Ó Nualláin, Breanndán
2000-01-01
Niche width theory, a part of organizational ecology, predicts whether “specialist” or “generalist” forms of organizations have higher “fitness,” in a continually changing environment. To this end, niche width theory uses a mathematical model borrowed from biology. In this paper, we first loosen th
2010-01-01
... 7 Agriculture 2 2010-01-01 2010-01-01 false Width. 29.1085 Section 29.1085 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Heavy Fleshy Medium Thin Oil Lean Oily Rich Color intensity Pale Weak Moderate Strong Deep. Width...
Radiating dipoles in photonic crystals
Busch; Vats; John; Sanders
2000-09-01
The radiation dynamics of a dipole antenna embedded in a photonic crystal are modeled by an initially excited harmonic oscillator coupled to a non-Markovian bath of harmonic oscillators representing the colored electromagnetic vacuum within the crystal. Realistic coupling constants based on the natural modes of the photonic crystal, i.e., Bloch waves and their associated dispersion relation, are derived. For simple model systems, well-known results such as decay times and emission spectra are reproduced. This approach enables direct incorporation of realistic band structure computations into studies of radiative emission from atoms and molecules within photonic crystals. We therefore provide a predictive and interpretative tool for experiments in both the microwave and optical regimes.
Wada Masayuki
2012-11-01
Full Text Available The results of resonance particle productions (ρ0, ω, K*, ϕ, Σ*, and Λ* measured by the STAR collaboration at RHIC from various colliding systems and energies are presented. Measured mass, width, 〈pT〉, and yield of those resonances are reviewed. No significant mass shifts or width broadening beyond the experiment uncertainties are observed. New measurements of ϕ and ω from leptonic decay channels are presented. The yields from leptonic decay channels are compared with the measurements from hadronic decay channels and the two results are consistent with each other.
Gravitational radiation from a rotating magnetic dipole
Hacyan, Shahen
2016-01-01
The gravitational radiation emitted by a rotating magnetic dipole is calculated. Formulas for the polarization amplitudes and the radiated power are obtained in closed forms, considering both the near and radiation zones of the dipole. For a neutron star, a comparison is made with other sources of gravitational and electromagnetic radiation.
Magnetic dipole oscillations and radiation damping
Stump, Daniel R.; Pollack, Gerald L.
1997-01-01
We consider the problem of radiation damping for a magnetic dipole oscillating in a magnetic field. An equation for the radiation reaction torque is derived, and the damping of the oscillations is described. Also discussed are runaway solutions for a rotating magnetic dipole moving under the influence of the reaction torque, with no external torque.
How to Introduce the Magnetic Dipole Moment
Bezerra, M.; Kort-Kamp, W. J. M.; Cougo-Pinto, M. V.; Farina, C.
2012-01-01
We show how the concept of the magnetic dipole moment can be introduced in the same way as the concept of the electric dipole moment in introductory courses on electromagnetism. Considering a localized steady current distribution, we make a Taylor expansion directly in the Biot-Savart law to obtain, explicitly, the dominant contribution of the…
Electric dipoles on the Bloch sphere
Vutha, Amar C
2014-01-01
The time evolution of a two-level quantum mechanical system can be geometrically described using the Bloch sphere. By mapping the Bloch sphere evolution onto the dynamics of oscillating electric dipoles, we provide a physically intuitive link between classical electromagnetism and the electric dipole transitions of atomic & molecular physics.
Direct summation of dipole-dipole interactions using the Wolf formalism.
Stenqvist, Björn; Trulsson, Martin; Abrikosov, Alexei I; Lund, Mikael
2015-07-07
We present an expanded Wolf formalism for direct summation of long-range dipole-dipole interactions and rule-of-thumbs how to choose optimal spherical cutoff (Rc) and damping parameter (α). This is done by comparing liquid radial distribution functions, dipole-dipole orientation correlations, particle energies, and dielectric constants, with Ewald sums and the Reaction field method. The resulting rule states that ασ 3 for reduced densities around ρ(∗) = 1 where σ is the particle size. Being a pair potential, the presented approach scales linearly with system size and is applicable to simulations involving point dipoles such as the Stockmayer fluid and polarizable water models.
Electron paramagnetic resonance study of ternary CuII compounds with glycine and phenanthroline
Ricardo C Santana; Anderson B C Araújo; Jesiel F Carvalho; Rafael Calvo
2014-01-01
We report here electron paramagnetic resonance (EPR) measurements at 9 and 34 GHz, and room temperature (), in powder and single crystal samples of the ternary compounds of copper nitrate or copper chloride with glycine and 1,10-phenanthroline [Cu(Gly)(phen)(H2O)]·NO3·1.5H2O (1) and [Cu(Gly)(phen)Cl]2·7H2O (2). In compound 1, the copper ions are arranged in 1-D chains along one of the crystal axes connected by syn-anti carboxylate ligands, while in 2 the array is nearly 3-D and the connections involve -bonds and stacking interactions. The angular variation of the squared g-factor and the line width were measured as a function of orientation of the magnetic field (0) in three orthogonal crystal planes. In both compounds we observed one resonance without hyperfine structure for any magnetic field orientation which we attribute to the collapse of the hyperfine coupling and of the resonances of two chemically identical but rotated coppers in the unit cell, produced by exchange interactions. We analyse the results in terms of the structures of the compounds and chemical paths connecting neighbour copper ions which support the exchange interactions between neighbour spins in the lattice. Considering the collapse of the EPR signals of rotated sites in the lattices we are able to set lower limits to the exchange interactions, which are supported by weak equatorial-apical carboxylate bridges in 1, and by paths containing hydrogen bonds and aromatic - interactions in 2. Broadening due to dipole-dipole couplings and hyperfine interactions are strongly reduced by these exchange couplings and their role in the EPR line width is more difficult to recognize.
Cross resonant optical antenna.
Biagioni, P; Huang, J S; Duò, L; Finazzi, M; Hecht, B
2009-06-26
We propose a novel cross resonant optical antenna consisting of two perpendicular nanosized gold dipole antennas with a common feed gap. We demonstrate that the cross antenna is able to convert propagating fields of any polarization state into correspondingly polarized, localized, and enhanced fields and vice versa. The cross antenna structure therefore opens the road towards the control of light-matter interactions based on polarized light as well as the analysis of polarized fields on the nanometer scale.
Cross Resonant Optical Antenna
Biagioni, P.; Huang, J. S.; Duò, L.; Finazzi, M.; Hecht, B.
2009-06-01
We propose a novel cross resonant optical antenna consisting of two perpendicular nanosized gold dipole antennas with a common feed gap. We demonstrate that the cross antenna is able to convert propagating fields of any polarization state into correspondingly polarized, localized, and enhanced fields and vice versa. The cross antenna structure therefore opens the road towards the control of light-matter interactions based on polarized light as well as the analysis of polarized fields on the nanometer scale.
Multiscale dipole relaxation in dielectric materials
Hansen, Jesper Schmidt
2016-01-01
the cross coupling between the electric field fluctuations and dipole moment fluctuations can be ignored. The peak frequencies in the spectra of the autocorrelation functions are also derived. They depend on the wave vector squared which is a fingerprint of the underlying dipole diffusion mechanism....... For the longitudinal direction the simulation results show that the cross coupling between the electric field and the dipole moment is non-negligible compromising the theoretical predictions. The underlying mechanism for this coupling is not clear.......Dipole relaxation from thermally induced perturbations is investigated on different length scales for dielectric materials. From the continuum dynamical equations for the polarisation, expressions for the transverse and longitudinal dipole autocorrelation functions are derived in the limit where...
High-field dipoles for future accelerators
Wipf, S.L.
1984-09-01
This report presents the concept for building superconducting accelerator dipoles with record high fields. Economic considerations favor the highest possible current density in the windings. Further discussion indicates that there is an optimal range of pinning strength for a superconducting material and that it is not likely for multifilamentary conductors to ever equal the potential performance of tape conductors. A dipole design with a tape-wound, inner high-field winding is suggested. Methods are detailed to avoid degradation caused by flux jumps and to overcome problems with the dipole ends. Concerns for force support structure and field precision are also addressed. An R and D program leading to a prototype 11-T dipole is outlined. Past and future importance of superconductivity to high-energy physics is evident from a short historical survey. Successful dipoles in the 10- to 20-T range will allow interesting options for upgrading present largest accelerators.
Minimum Q Electrically Small Spherical Magnetic Dipole Antenna - Practice
Kim, Oleksiy S.; Breinbjerg, Olav
2009-01-01
resonances of all other modes that are not sufficiently suppressed in the antenna. Numerical results for a 4-arm spherical helix antenna filled with magnetic material demonstrate the destroying effect of the parasitic TM11 mode on the antenna Q factor. Theoretical considerations as well as numerical results......Practical aspects of applying a magnetic core to approach the Chu lower bound for the radiation Q factor of an electrically small magnetic dipole antenna are considered. It is shown that although a magnetic core does reduce the Q factor, its effect is not as strong as predicted by Wheeler...... show that in a given range of magnetic permeabilities away from core resonances there is an optimum permeability for which the Q factor is lowest. In the given example, the antenna of the size ka~0.254 yields the Q ratio 1.28 times above the Chu lower bound....
Yang Yi-Ming; Wang Jia-Fu; Xia Song; Bai Peng; Li Zhe; Wang Jun; Xu Zhuo; Qu Shao-Bo
2011-01-01
Dipoles with Lorentz-type resonant electromagnetic responses can realise negative effective parameters in their negative resonant region. The electric dipole and magnetic dipole can realise, respectively, negative permittivity and negative permeability, so both the field distribution forms of electric and magnetic dipoles are fundamentals in designing left-handed metamaterial. Based on this principle, this paper studies the field distribution in high-permittivity dielectric materials. The field distributions at different resonant modes are analysed based on the dielectric resonator theory. The origination and influence factors of the electric and magnetic dipoles are confirmed. Numerical simulations indicate that by combining dielectric cubes with different sizes, the electric resonance frequency and magnetic resonance frequency can be superposed. Finally, experiments are carried out to verify the feasibility of all-dielectric left-handed metamaterial composed by this means.
On the width of N-Delta and Delta-Delta states
Niskanen, J A
2016-01-01
It is seen by a coupled-channel calculation that in the two-baryon N-Delta or Delta-Delta system the width of the state is greatly diminished due to the relative kinetic energy of the two baryons, since the internal energy of the particles, available for pionic decay, is smaller. A similar state dependent effect arises from the centrifugal barrier in N-Delta or Delta-Delta systems with non-zero orbital angular momentum. The double-Delta width can become even smaller than the free width of a single Delta. This has some bearing to the interpretation of the d'(2380) resonance recently discovered at COSY.
A periodic charge-dipole electrostatic model: parametrization for silver slabs.
Bodrenko, I V; Sierka, M; Fabiano, E; Della Sala, F
2012-10-07
We present an extension of the charge-dipole model for the description of periodic systems. This periodic charge-dipole electrostatic model (PCDEM) allows one to describe the linear response of periodic structures in terms of charge- and dipole-type gaussian basis functions. The long-range electrostatic interaction is efficiently described by means of the continuous fast multipole method. As a first application, the PCDEM method is applied to describe the polarizability of silver slabs. We find that for a correct description of the polarizability of the slabs both charges and dipoles are required. However a continuum set of parametrizations, i.e., different values of the width of charge- and dipole-type gaussians, leads to an equivalent and accurate description of the slabs polarizability but a completely unphysical description of induced charge-density inside the slab. We introduced the integral squared density measure which allows one to obtain a unique parametrization which accurately describes both the polarizability and the induced density profile inside the slab. Finally the limits of the electrostatic approximations are also pointed out.
Dipole oscillation modes in $\\alpha$-clustering light nuclei
He, W B; Cao, X G; Cai, X Z; Zhang, G Q
2016-01-01
The alpha cluster states are discussed in an extended quantum molecular dynamics (EQMD) model frame. Different alpha cluster structures are studied in details, such as $^8$Be two-alpha cluster structure, $^{12}$C triangle structure, $^{12}$C chain structure, $^{16}$O chain structure, $^{16}$O kite structure, and $^{16}$O square structure. The properties like width of wave packets for different alpha clusters, momentum distribution, and the binding energy among alpha clusters are studied. It is also discussed how the $\\alpha$ cluster degree of freedom affects nuclear collective vibrations. The different $\\alpha$ cluster configurations in $^{12}$C and $^{16}$O have corresponding characteristic spectra of GDR and the coherence of different alpha clusters's dipole oscillation are described in details. The number and centroid energies of peaks in the GDR spectra can be reasonably explained by the geometrical and dynamical symmetries of $\\alpha$-clustering configurations. The GDR can be regarded as a very effective...
Discrete Dipole Approximation Aided Design Method for Nanostructure Arrays
ZHU Shao-Li; LUO Xian-Gang; DU Chun-Lei
2007-01-01
A discrete dipole approximation (DDA) aided design method is proposed to determine the parameters of nanostructure arrays. The relationship between the thickness, period and extinction efficiency of nanostructure arrays for the given shape can be calculated using the DDA. Based on the calculated curves, the main parameters of the nanostructure arrays such as thickness and period can be determined. Using this aided method, a rhombic sliver nanostructure array is designed with the determinant parameters of thickness (40 nm) and period (440 nm).We further fabricate the rhombic sliver nanostructure arrays and testify the character of the extinction spectra.The obtained extinction spectra is within the visible range and the full width at half maximum is 99nm, as is expected.
Multiband Printed Asymmetric Dipole Antenna for LTE/WLAN Applications
Chia-Mei Peng
2013-01-01
Full Text Available The ability of a single layer strip fed printed asymmetric dipole antenna, which is composed of top-loading, asymmetric coplanar waveguide (ACPW and stepped-feeding structure, to operate at three wide frequency bands (698~960 MHz, 1710~2620 MHz, and 5150~5850 MHz to cover WLAN and LTE operation has been demonstrated. A prototype of the proposed antenna with 57.5 mm in length, 0.4 mm in thickness, and 5 mm in width is fabricated and experimentally investigated. The experimental results indicate that the VSWR 2.5 : 1 bandwidths achieved were 74.3%, 40.8%, and 18.2% at 700 MHz, 2450 MHz, and 5500 MHz, respectively. Experimental results are shown to verify the validity of theoretical work.
Free induction decay caused by a dipole field
Ziener, C. H.; Kurz, F. T.; Kampf, T.
2015-03-01
We analyze the free induction decay of nuclear spins under the influence of restricted diffusion in a magnetic dipole field around cylindrical objects. In contrast to previous publications no restrictions or simplifications concerning the diffusion process are made. By directly solving the Bloch-Torrey equation, analytical expressions for the magnetization are given in terms of an eigenfunction expansion. The field strength-dependent complex nature of the eigenvalue spectrum significantly influences the shape of the free induction decay. As the dipole field is the lowest order of the multipole expansion, the obtained results are important for understanding fundamental mechanisms of spin dephasing in many other applied fields of nuclear magnetic resonance such as biophysics or material science. The analytical methods are applied to interpret the spin dephasing in the free induction decay in cardiac muscle and skeletal muscle. A simple expression for the relevant transverse relaxation time is found in terms of the underlying microscopic parameters of the muscle tissue. The analytical results are in agreement with experimental data. These findings are important for the correct interpretation of magnetic resonance images for clinical diagnosis at all magnetic field strengths and therapy of cardiovascular diseases.
Fernandez-Ramirez, C. [Grupo de Fisica Nuclear, Departamento de Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain)], E-mail: cesar@nuc2.fis.ucm.es; Moya de Guerra, E. [Grupo de Fisica Nuclear, Departamento de Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain); Instituto de Estructura de la Materia, CSIC, Serrano 123, E-28006 Madrid (Spain); Udias, J.M. [Grupo de Fisica Nuclear, Departamento de Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain)
2008-02-21
We investigate the importance of crossing symmetry in effective field models and the effects of phenomenological nucleon resonance widths on the paradigmatic case of pion photoproduction. We use reaction models containing four star resonances up to 1.8 GeV ({delta}(1232), N(1440), N(1520), N(1535), {delta}(1620), N(1650), {delta}(1700), and N(1720)) with different prescriptions for crossed terms and widths, to fit the latest world database on pion photoproduction. We compare {chi}{sup 2} results from selected multipoles and fits. The {chi}{sup 2} is highly dependent on the fulfillment of crossing symmetry and the inclusion of u channels.
Effective restoration of dipole sum rules within the renormalized random-phase approximation
Hung, N. Quang; Dang, N. Dinh; Hao, T. V. Nhan; Phuc, L. Tan
2016-12-01
The dipole excitations for calcium and zirconium isotopes are studied within the fully self-consistent Hartree-Fock mean field incorporated with the renormalized random-phase approximation (RRPA) using the Skyrme interaction SLy5. The RRPA takes into account the effect of ground-state correlations beyond RPA owing to the Pauli principle between the particle-hole pairs that form the RPA excitations as well as the correlations due to the particle-particle and hole-hole transitions, whose effects are treated here in an effective way. By comparing the RPA results with the RRPA ones, which are obtained for isoscalar (IS) and isovector (IV) dipole excitations in 48,52,58Ca and 90,96,110Zr, it is shown that ground-state correlations beyond the RPA reduce the IS transition strengths. They also shift up the energy of the lowest IV dipole state and slightly push down the peak energy of the IV giant dipole resonance. As the result, the energy-weighted sums of strengths of both IS and IV modes decrease, causing the violation of the corresponding energy-weighted sum rules (EWSR). It is shown that this sum rule violation can be eliminated by taking into account the contribution of the particle-particle and hole-hole excitations together with the particle-hole ones in a simple and perturbative way. Consequently, the ratio of the energy-weighted sum of strengths of the pygmy dipole resonance to that of the giant dipole resonance increases.
Spectral distortions of the CMB dipole
Balashev, S A; Chluba, J; Ivanchik, A V; Varshalovich, D A
2015-01-01
We consider the distortions of the CMB dipole anisotropy related to the primordial recombination radiation (PRR) and primordial $y$- and $\\mu$-distortions. The signals arise due to our motion relative to the CMB restframe and appear as a frequency-dependent distortion of the CMB temperature dipole. To leading order, the expected relative distortion of CMB dipole does not depend on the particular observation directions and reaches the level of $10^{-6}$ for the PRR- and $\\mu$-distortions and $10^{-5}$ for the $y$-distortion in the frequency range 1 $-$ 700 GHz. The temperature differences arising from the dipole anisotropy of the relic CMB distortions depend on observation directions. For mutually opposite directions, collinear to the CMB dipole axis, the temperature differences because of the PRR- and $\\mu$-dipole anisotropy attain values $\\Delta T\\simeq 10\\,$nK in the considered range. The temperature difference arising from the $y$-dipole anisotropy may reach values up to $1\\,\\mu$K. The key features of the ...
Nonadiabatic Induced Dipole Moment by High Intensity Femtosecond Optical Pulses
Koprinkov, I. G.
2006-01-01
Nonadiabtic dressed states and nonadiabatic induced dipole moment in the leading order of nonadiabaticity is proposed. The nonadiabatic induced dipole moment is studied in the femtosecond time domain.
Applicability of point-dipoles approximation to all-dielectric metamaterials
Kuznetsova, S. M.; Andryieuski, Andrei; Lavrinenko, Andrei
2015-01-01
All-dielectric metamaterials consisting of high-dielectric inclusions in a low-dielectric matrix are considered as a low-loss alternative to resonant metal-based metamaterials. In this paper we investigate the applicability of the point electric and magnetic dipoles approximation to dielectric meta......-atoms on the example of a dielectric ring metamaterial. Despite the large electrical size of high-dielectric meta-atoms, the dipole approximation allows for accurate prediction of the metamaterials properties for the rings with diameters up to approximate to 0.8 of the lattice constant. The results provide important...... guidelines for design and optimization of all-dielectric metamaterials....
Schoun, S. B.; Camper, A.; Salières, P.; Lucchese, R. R.; Agostini, P.; DiMauro, L. F.
2017-01-01
We report on spectral intensity and group delay measurements of the highest-occupied molecular-orbital (HOMO) recombination dipole moment of N2 in the molecular-frame using high harmonic spectroscopy. We take advantage of the long-wavelength 1.3 μ m driving laser to isolate the HOMO in the near threshold region, 19-67 eV. The precision of our group delay measurements reveals previously unseen angle-resolved spectral features associated with autoionizing resonances, and allows quantitative comparison with cutting-edge correlated 8-channel photoionization dipole moment calculations.
ϕ meson mass and decay width in nuclear matter and nuclei
Cobos-Martínez, J. J.; Tsushima, K.; Krein, G.; Thomas, A. W.
2017-08-01
The mass and decay width of the ϕ meson in cold nuclear matter are computed in an effective Lagrangian approach. The medium dependence of these properties are obtained by evaluating kaon-antikaon loop contributions to the ϕ self-energy, employing the medium-modified kaon masses, calculated using the quark-meson coupling model. The loop integral is regularized with a dipole form factor, and the sensitivity of the results to the choice of cutoff mass in the form factor is investigated. At normal nuclear matter density we find a downward shift of the ϕ mass by a few percent, while the decay width is enhanced by an order of magnitude. For a large variation of the cutoff mass parameter, the results for the ϕ mass and the decay width turn out to vary very little. Our results support results in the literature which suggest that one should observe a small downward mass shift and a large broadening of the decay width. In order to explore the possibility of studying the binding and absorption of ϕ mesons in nuclei, we also present the single-particle binding energies and half-widths of ϕ-nucleus bound states for some selected nuclei.
On the Spectrum Width of Wind Waves
李陆平; 黄培基
2001-01-01
Based on the universal expression of wind wave spectra, four commonly used definitions of the spectrum width arere-examined. The results show that the non-dimensional spectrum width can measure the width of non-dimensionalspectra but it does not reflect the developing state of the spectra. The dimensional spectrum width expresses the degree ofconcentration of wave energy of the spectrum in the process of wind wave growth. Tests show that the spectrum widthpresented by Wen et al. can objectively measure the degree of concentration of wave energy of the spectrum, reflect thestate of wind wave growth, and provides a better result for practical application. The rules for definition of the spectrumwidth are discussed.
Bipartite Graphs of Large Clique-Width
Korpelainen, Nicholas; Lozin, Vadim V.
Recently, several constructions of bipartite graphs of large clique-width have been discovered in the literature. In the present paper, we propose a general framework for developing such constructions and use it to obtain new results on this topic.
Formation number for vortex dipoles
Sadri, Vahid; Krueger, Paul S.
2016-11-01
This investigation considers the axisymmetric formation of two opposite sign concentric vortex rings from jet ejection between concentric cylinders. This arrangement is similar to planar flow in that the vortex rings will travel together when the gap between the cylinders is small, similar to a vortex dipole, but it has the advantage that the vortex motion is less constrained than the planar case (vortex stretching and vortex line curvature is allowed). The flow was simulated numerically at a jet Reynolds number of 1,000 (based on ΔR and the jet velocity), jet pulse length-to-gap ratio (L / ΔR) in the range 10-20, and gap-to-outer radius ratio (ΔR /Ro) in the range 0.01-0.1. Small gap ratios were chosen for comparison with 2D results. In contrast with 2D results, the closely paired vortices in this study exhibited pinch-off from the generating flow and finite formation numbers. The more complex flow evolution afforded by the axisymmetric model and its influence on the pinch-off process will be discussed. This material is based on work supported by the National Science Foundation under Grant No. 1133876 and SMU. This supports are gratefully acknowledged.
Superconducting Coil of Po Dipole
1983-01-01
The Po superconducting dipole was built as a prototype beam transport magnet for the SPS extracted proton beam P0. Its main features were: coil aperture 72 mm, length 5 m, room-temperature yoke, NbTi cable conductor impregnated with solder, nominal field 4.2 T at 4.7 K (87% of critical field). It reached its nominal field without any quench.After this successful test up to its nominal field of 4.2 T, the power was not raised to reach a quench. The magnet was not installed in a beam and had no other further use. Nevertheless its construction provided knowledges and experience which became useful in the design and construction of the LHC magnets. The photo shows a detail of the inner layer winding before superposing the outer layer to form the complete coil of a pole. Worth noticing is the interleaved glass-epoxy sheet (white) with grooved channels for the flow of cooling helium. See also 8211532X.
Axion induced oscillating electric dipole moments
Hill, Christopher T. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
2015-06-24
In this study, the axion electromagnetic anomaly induces an oscillating electric dipole for any magnetic dipole. This is a low energy theorem which is a consequence of the space-time dependent cosmic background field of the axion. The electron will acquire an oscillating electric dipole of frequency m_{a} and strength ~ 10^{-32} e-cm, within four orders of magnitude of the present standard model DC limit, and two orders of magnitude above the nucleon, assuming standard axion model and dark matter parameters. This may suggest sensitive new experimental venues for the axion dark matter search.
Collisional blockade in microscopic optical dipole traps.
Schlosser, N; Reymond, G; Grangier, P
2002-07-08
We analyze the operating regimes of a very small optical dipole trap, loaded from a magneto-optical trap, as a function of the atom loading rate, i.e., the number of atoms per second entering the dipole trap. We show that, when the dipole trap volume is small enough, a "collisional blockade" mechanism locks the average number of trapped atoms on the value 0.5 over a large range of loading rates. We also discuss the "weak loading" and "strong loading" regimes outside the blockade range, and we demonstrate experimentally the existence of these three regimes.
Kurien, Anjana; Cherian, K P; Mhatre, Shirley; Tharakan, Renji George
2014-01-01
This study was done to determine the relationship between interalar width and inter commissural width on circumferential arc width of maxillary anterior teeth in dentulous subjects between the age groups of 20–50 years...
Electric and Magnetic Dipole Coupling in Near-Infrared Split-Ring Metamaterial Arrays
Sersic, Ivana; Frimmer, Martin; Verhagen, Ewold; Koenderink, A. Femius
2009-11-01
We present experimental observations of strong electric and magnetic interactions between split ring resonators (SRRs) in metamaterials. We fabricated near-infrared planar metamaterials with different inter-SRR spacings along different directions. Our transmission measurements show blueshifts and redshifts of the magnetic resonance, depending on SRR orientation relative to the lattice. The shifts agree well with simultaneous magnetic and electric near-field dipole coupling. We also find large broadening of the resonance, accompanied by a decrease in effective cross section per SRR with increasing density due to superradiant scattering. Our data shed new light on Lorentz-Lorenz approaches to metamaterials.
Dang, Nguyen Dinh
2007-04-01
Thermal fluctuations of quasiparticle number are included making use of the secondary Bogolyubov's transformation, which turns quasiparticles operators into modified-quasiparticle ones. This restores the unitarity relation for the generalized single-particle density operator, which is violated within the Hartree-Fock-Bogolyubov (HFB) theory at finite temperature. The resulting theory is called the modified HFB (MHFB) theory, whose limit of a constant pairing interaction yields the modified BCS (MBCS) theory. Within the MBCS theory, the pairing gap never collapses at finite temperature T as it does within the BCS theory, but decreases monotonously with increasing T. It is demonstrated that this non-vanishing thermal pairing is the reason why the width of the giant dipole resonance (GDR) does not increase with T up to T ~ 1 MeV. At higher T, when the thermal pairing is small, the GDR width starts to increase with T. The calculations within the phonon-damping model yield the results in good agreement with the most recent experimental systematic for the GDR width as a function of T. A similar effect, which causes a small GDR width at low T, is also seen after thermal pairing is included in the thermal fluctuation model.
Sharma, M. [Dept. of Physics and Astro-Physics, Univ. of Delhi (India); Govind, N.; Pratap, A. [Condense Matter Theory Group, National Physical Lab., New Delhi (India); Ajay; Tripathi, R.S. [Dept. of Physics, G.B. Pant Univ. of Agriculture and Technology, Pantnagar (India)
2001-07-01
In the present paper, we report the role of dipole-dipole interaction on the magnetic dynamics of single layer antiferromagnets. For this, the model Hamiltonian includes the exchange Heisenberg Hamiltonian as well as dipole-dipole interactions. Within the linear spin-wave theory, we employ the double time Green's function technique to obtain expressions for the spin wave dispersion, sublattice magnetization and the magnetic contribution to specific heat as a function of various parameters of the model Hamiltonian. We observe through numerical calculations that in the absence of anisotropy in exchange couplings the dipole-dipole interaction works as an anisotropy and sustains the magnetization even in a pure 2D system. (orig.)
Plasmonic functionalities based on detuned electrical dipoles
Pors, Anders Lambertus; Nielsen, Michael Grøndahl; Bozhevolnyi, Sergey I.
2013-01-01
We introduce and demonstrate the concept of detuned electrical dipoles (DED) that originates from the plasmonic realization of the dressed-state picture of electromagnetically induced transparency in atomic physics. Numerically and experimentally analyzing DED metamaterials consisting of unit cells...
Plasmonic functionalities based on detuned electrical dipoles
Pors, Anders Lambertus; Nielsen, Michael Grøndahl; Bozhevolnyi, Sergey I.
2013-01-01
We introduce and demonstrate the concept of detuned electrical dipoles (DED) that originates from the plasmonic realization of the dressed-state picture of electromagnetically induced transparency in atomic physics. Numerically and experimentally analyzing DED metamaterials consisting of unit cells...
Dynamic evolution of coherent vortex dipole in atmospheric turbulence
Li, Jinhong; Zeng, Jun
2017-01-01
The analytical expression for the cross-spectral density function of Gaussian Schell-model (GSM) beams with coherent vortex dipole (CVD) propagating through atmospheric turbulence is derived, which enables us to study the evolution process of CVD propagating through atmospheric turbulence, where the influences of the beams parameters and atmospheric turbulence parameters on the ratio of critical off-axis distance to the waist width are stressed. It shows that the evolution process of the CVD depends on the off-axis distance. The larger the off-axis distance is, the more the number of CVD is. When the off-axis distance is zero, the position of coherent vortices with positive and negative topological charge of CVD propagating through atmospheric turbulence is always symmetry. When the off-axis distance is big enough, compared with the situation at source plane, the orientation of the positive coherent vortex of inherent CVD and negative coherent vortex of that rotates 180° in the far field. The larger the structure constant and the waist width are, as well as the smaller the spatial correlation length and the inner scale are, the smaller the ratio ac/w0 is. Besides, the ratio ac/w0 will no longer change when the spatial correlation length or the inner scale increases to a certain value, whereas the outer scale has no effect on the ratio.
Population Dynamics in Cold Gases Resulting from the Long-Range Dipole-Dipole Interaction
Mandilara, A; Pillet, P
2009-01-01
We consider the effect of the long range dipole-dipole interaction on the excitation exchange dynamics of cold two-level atomic gase in the conditions where the size of the atomic cloud is large as compared to the wavelength of the dipole transition. We show that this interaction results in population redistribution across the atomic cloud and in specific spectra of the spontaneous photons emitted at different angles with respect to the direction of atomic polarization.
Cosmological CMBR dipole in open universes?
Langlois, D
1997-01-01
The observed CMBR dipole is generally interpreted as a Doppler effect arising from the motion of the Earth relative to the CMBR frame. An alternative interpretation, proposed in the last years, is that the dipole results from ultra-large scale isocurvature perturbations. We examine this idea in the context of open cosmologies and show that the isocurvature interpretation is not valid in an open universe, unless it is extremely close to a flat universe, $|\\Omega_0 -1|< 10^{-4}$.
On the dipole moment of CO/+/.
Certain, P. R.; Woods, R. C.
1973-01-01
Results of self-consistent field calculations on neutral CO, its positive ion, and on neutral CN to verify an earlier estimate of the dipole moment of CO(+) in its ground super 2 Sigma state. Based on the above-mentioned calculations, direct evidence is obtained that the dipole moment (relative to the center of mass) is approximately 2.5 plus or minus 0.5 C, as previously determined by Kopelman and Klemperer (1962).
Self-formed cavity quantum electrodynamics in coupled dipole cylindrical-waveguide systems.
Afshar V, S; Henderson, M R; Greentree, A D; Gibson, B C; Monro, T M
2014-05-01
An ideal optical cavity operates by confining light in all three dimensions. We show that a cylindrical waveguide can provide the longitudinal confinement required to form a two dimensional cavity, described here as a self-formed cavity, by locating a dipole, directed along the waveguide, on the interface of the waveguide. The cavity resonance modes lead to peaks in the radiation of the dipole-waveguide system that have no contribution due to the skew rays that exist in longitudinally invariant waveguides and reduce their Q-factor. Using a theoretical model, we evaluate the Q-factor and modal volume of the cavity formed by a dipole-cylindrical-waveguide system and show that such a cavity allows access to both the strong and weak coupling regimes of cavity quantum electrodynamics.
Intrinsic Decoherence of a Two-Atom System with Dipole-Dipole Interaction
QI Lin-Na; ZHU Ai-Dong; ZHANG Shou
2008-01-01
@@ We investigate the effect of dipole-dipole interaction on the intrinsic decoherence of a system which consists of two two-level atoms and an optical cavity. The entanglement of the system is calculated by making use of concurrence. Our results show that the appropriate choice for the coupling constant Ω of dipole-dipole interaction can restrain the intrinsic decoherence of the system. We also find a special phenomenon. No matter what the value of γ is, the concurrence of system slowly increases and cannot exceed 0.71 when Ω= 1.
Dipole-moment-driven cooperative supramolecular polymerization.
Kulkarni, Chidambar; Bejagam, Karteek K; Senanayak, Satyaprasad P; Narayan, K S; Balasubramanian, S; George, Subi J
2015-03-25
While the mechanism of self-assembly of π-conjugated molecules has been well studied to gain control over the structure and functionality of supramolecular polymers, the intermolecular interactions underpinning it are poorly understood. Here, we study the mechanism of self-assembly of perylene bisimide derivatives possessing dipolar carbonate groups as linkers. It was observed that the combination of carbonate linkers and cholesterol/dihydrocholesterol self-assembling moieties led to a cooperative mechanism of self-assembly. Atomistic molecular dynamics simulations of an assembly in explicit solvent strongly suggest that the dipole-dipole interaction between the carbonate groups imparts a macro-dipolar character to the assembly. This is confirmed experimentally through the observation of a significant polarization in the bulk phase for molecules following a cooperative mechanism. The cooperativity is attributed to the presence of dipole-dipole interaction in the assembly. Thus, anisotropic long-range intermolecular interactions such as dipole-dipole interaction can serve as a way to obtain cooperative self-assembly and aid in rationalizing and predicting the mechanisms in various synthetic supramolecular polymers.
Polarization effects in recoil-induced resonances
Lazebnyi, D. B.; Brazhnikov, D. V.; Taichenachev, A. V.; Yudin, V. I.
2017-01-01
The effect of the field polarization on the amplitude of recoil-induced resonances (RIRs) is considered for laser-cooled free atoms and for atoms in a working magneto-optical trap (MOT). For all closed dipole transitions, explicit analytical expressions are obtained for the polarization dependence of the resonance amplitudes within a perturbation theory. Optimal polarization conditions are found for the observation of resonances.
Polarization effects in recoil-induced resonances
Lazebnyi, D. B., E-mail: becks.ddf@gmail.com; Brazhnikov, D. V.; Taichenachev, A. V.; Yudin, V. I. [Russian Academy of Sciences, Institute of Laser Physics, Siberian Branch (Russian Federation)
2017-01-15
The effect of the field polarization on the amplitude of recoil-induced resonances (RIRs) is considered for laser-cooled free atoms and for atoms in a working magneto-optical trap (MOT). For all closed dipole transitions, explicit analytical expressions are obtained for the polarization dependence of the resonance amplitudes within a perturbation theory. Optimal polarization conditions are found for the observation of resonances.
Torque-mixing Magnetic Resonance Spectroscopy
Losby, Joseph; Fani Sani, Fatemeh; Grandmont, Dylan; Diao, Zhu; Belov, Miro; Burgess, Jacob; Compton, Shawn; Hiebert, Wayne; Vick, Doug; Mohammad, Kaveh; Salimi, Elham; Bridges, Gregory; Thomson, Douglas; Freeman, Mark
A universal, mechanical torque method for magnetic resonance spectroscopy is presented. In analogy to resonance detection by induction, a signal proportional to the transverse component of a precessing dipole moment can be measured as a pure mechanical torque in broadband, frequency-swept spectroscopy. Comprehensive electron spin resonance of a single-crystal, mesoscopic yttrium iron garnet disk at room temperature are presented to demonstrate the method. The rich detail allows analysis of even complex 3D spin textures.
Constraints on widths of mixed pentaquark multiplets
Mohta, V
2004-01-01
We determine constraints on the partial widths of mixed pentaquark multiplets in the framework of heavy baryon chiral perturbation theory (HB$\\chi$PT). The partial widths satisfy a GMO-type relation at leading order in HB$\\chi$PT, for arbitrary mixing. The widths of N(1440), N(1710), and $\\Theta(1540)$ are not consistent with ideal mixing, $\\theta_{N} = 35.3^{\\circ}$, but are consistent with $\\theta_{N} \\lesssim 25^{\\circ}$. Furthermore, there are parameter values in HB$\\chi$PT that produce such a mixing angle while allowing the identification of the mass spectrum above. As an alternative to non-ideal mixing, we also suggest reasons for giving up on N(1440) as a pure pentaquark state.
The Variable Line Width of Achernar
Rivinius, Th; Baade, D; Carciofi, A C; Leister, N; Štefl, S
2016-01-01
Spectroscopic observations of Achernar over the past decades, have shown the photospheric line width, as measured by the rotational parameter $v \\sin i$, to vary in correlation with the emission activity. Here we present new observations, covering the most recent activity phase, and further archival data collected from the archives. The $v \\sin i$ variation is confirmed. On the basis of the available data it cannot be decided with certainty whether the increased line width precedes the emission activity, i.e. is a signature of the ejection mechanism, or postdates is, which would make it a signature of re-accretion of some of the disk-material. However, the observed evidence leans towards the re-accretion hypothesis. Two further stars showing the effect of variable line width in correlation with emission activity, namely 66 Oph and $\\pi$ Aqr, are presented as well.
Graph Operations on Clique-Width Bounded Graphs
Gurski, Frank
2007-01-01
Clique-width is a well-known graph parameter. Many NP-hard graph problems admit polynomial-time solutions when restricted to graphs of bounded clique-width. The same holds for NLC-width. In this paper we study the behavior of clique-width and NLC-width under various graph operations and graph transformations. We give upper and lower bounds for the clique-width and NLC-width of the modified graphs in terms of the clique-width and NLC-width of the involved graphs.
Kovács, Tamás; Batta, Gyula; Hajdu, Tímea; Szabó, Ágnes; Váradi, Tímea; Zákány, Florina; Csomós, István; Szöllősi, János; Nagy, Peter
2016-01-01
Although activation of the ErbB family of receptor tyrosine kinases (ErbB1-4) is driven by oligomerization mediated by intermolecular interactions between the extracellular, the kinase and the transmembrane domains, the transmembrane domain has been largely neglected in this regard. The largest contributor to the intramembrane electric field, the dipole potential, alters the conformation of transmembrane peptides, but its effect on ErbB proteins is unknown. Here, we show by Förster resonance energy transfer (FRET) and number and brightness (N&B) experiments that the epidermal growth factor (EGF)-induced increase in the homoassociation of ErbB1 and ErbB2 and their heteroassociation are augmented by increasing the dipole potential. These effects were even more pronounced for ErbB2 harboring an activating Val → Glu mutation in the transmembrane domain (NeuT). The signaling capacity of ErbB1 and ErbB2 was also correlated with the dipole potential. Since the dipole potential decreased the affinity of EGF to ErbB1, the augmented growth factor-induced effects at an elevated dipole potential were actually induced at lower receptor occupancy. We conclude that the dipole potential plays a permissive role in the clustering of ErbB receptors and that the effects of lipid rafts on ligand binding and receptor signaling can be partially attributed to the dipole potential. PMID:27775011
Low-lying dipole strength in the N = 28 shell-closure nucleus {sup 52}Cr
Pai, Haridas; Beller, Jacob; Benouaret, Nadia; Enders, Joachim; Hartmann, Timo; Karg, Oliver; Neumann-Cosel, Peter von; Pietralla, Norbert; Ponomarev, Vladimir Yu.; Romig, Christopher; Schnorrenberger, Linda; Volz, Stephan; Zweidinger, Markus [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany); Scheck, Marcus [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany); School of Engineering, University of the West of Scotland, Paisley (United Kingdom); SUPA, Scottish Universities Physics Alliance, Glasgow (United Kingdom)
2014-07-01
Low-lying electric and magnetic dipole strengths (E1 and M1, respectively) of atomic nuclei have drawn considerable attention in the last decade. The low-lying dipole strength of the N = 28 closed-shell nucleus {sup 52}Cr was studied with nuclear resonance fluorescence up to 9.9 MeV, using bremsstrahlung at the superconducting Darmstadt electron linear accelerator S-DALINAC. Twenty-eight spin-1 states were observed between 5.0 and 9.5 MeV excitation energy, 14 of those for the first time and uncertainties for cross sections were reduced in many cases. Both, electric dipole excitations (E1, around 8 MeV) and magnetic dipole excitations (M1, around 9 MeV) were detected. Microscopic calculations within the quasiparticle-phonon nuclear model were performed using a basis which includes one-, two-, and three-phonon configurations to interpret the dipole strength distributions of {sup 52}Cr and show good agreement with experimental results.
Vlasov Simulations of Ionospheric Heating Near Upper Hybrid Resonance
Najmi, A. C.; Eliasson, B. E.; Shao, X.; Milikh, G. M.; Papadopoulos, K.
2014-12-01
It is well-known that high-frequency (HF) heating of the ionosphere can excite field- aligned density striations (FAS) in the ionospheric plasma. Furthermore, in the neighborhood of various resonances, the pump wave can undergo parametric instabilities to produce a variety of electrostatic and electromagnetic waves. We have used a Vlasov simulation with 1-spatial dimension, 2-velocity dimensions, and 2-components of fields, to study the effects of ionospheric heating when the pump frequency is in the vicinity of the upper hybrid resonance, employing parameters currently available at ionospheric heaters such as HAARP. We have found that by seeding theplasma with a FAS of width ~20% of the simulation domain, ~10% depletion, and by applying a spatially uniform HF dipole pump electric field, the pump wave gives rise to a broad spectrum of density fluctuations as well as to upper hybrid and lower hybrid oscillating electric fields. We also observe collisionless bulk-heating of the electrons that varies non-linearly with the amplitude of the pump field.
Wireline equalization using pulse-width modulation
Schrader, J.H.R.; Klumperink, Eric A.M.; Visschers, J.L.; Nauta, Bram
2006-01-01
Abstract-High-speed data links over copper cables can be effectively equalized using pulse-width modulation (PWM) pre-emphasis. This provides an alternative to the usual 2-tap FIR filters. The use of PWM pre-emphasis allows a channel loss at the Nyquist frequency of ~30dB, compared to ~20dB for a
LHC dipoles: the countdown has begun
Patrice Loiez
2002-01-01
At the entrance to the fourth floor corridor of the LHC-MMS (Main Magnets and Superconductors) Group in building 30, the Director-General has unveiled an electronic information panel indicating the number of LHC dipoles still to be delivered and the days remaining to the deadline (30 June 2006). The panel was the idea of Lucio Rossi, leader of the MMS Group, which is responsible for the construction of the dipole magnets. The unveiling ceremony took place on the morning of Friday 11 October 2002, at the end of a drink held to celebrate with MMS group and the LHC top management the exceptional performance of the latest dipoles, built by the French consortium Alstom-Jeumont. They are the first dipoles to achieve a magnetic field of 9 tesla in one go without quenching, thus exceeding the nominal operating field of 8.3 tesla. The challenge is now to increase the production rate from 2 to 35 dipoles per month by 2004 in order to meet the deadline, while maintaining this quality. Photo 01: The Director-General Luci...
Atomic Dipole Traps with Amplified Spontaneous Emission: A Proposal
Clément, Jean-François; Garreau, Jean Claude; Szriftgiser, Pascal
2010-01-01
We propose what we believe to be a novel type of optical source for ultra-cold atomic Far Off-Resonance optical-dipole Traps (FORTs). The source is based on an Erbium Amplified Spontaneous Emission (ASE) source that seeds a high power Erbium Doped Fiber Amplifier (EDFA). The main interest of this source is its very low coherence length, thus allowing an incoherent superposition of several trapping beams without any optical interference. The behavior of the superimposed beams is then a scalar sum greatly simplifying complex configurations. As an illustration, we report an estimation of the intensity noise of this source and an estimation of the atomic excess heating rate for an evaporative cooling experiment application. They are both found to be suitable for cold atoms experiments.
Frequency Domain Storage Ring Method for Electric Dipole Moment Measurement
Talman, Richard
2015-01-01
Precise measurement of the electric dipole moments (EDM) of fundamental charged particles would provide a significant probe of physics beyond the standard model. Any measurably large EDM would imply violation of both time reversal and parity conservation, with implications for the matter/anti-matter imbalance of the universe, not currently understood within the standard model. A frequency domain (i.e. difference of frequencies) method is proposed for measuring the EDM of electrons or protons or, with modifications, deuterons. Anticipated precision (i.e. reproducibility) is $10^{-30}\\,$e-cm for the proton EDM, with comparable accuracy (i.e. including systematic error). This would be almost six orders of magnitude smaller than the present upper limit, and will provide a stringent test of the standard model. Resonant polarimetry, made practical by the large polarized beam charge, is the key (most novel, least proven) element of the method. Along with the phase-locked, rolling polarization "Koop spin wheel," reso...
Low-cost, pseudo-Halbach dipole magnets for NMR
Tayler, Michael C. D.; Sakellariou, Dimitrios
2017-04-01
We present designs for compact, inexpensive and strong dipole permanent magnets aimed primarily at magnetic resonance applications where prepolarization and detection occur at different locations. Low-homogeneity magnets with a 7.5 mm bore size and field up to nearly 2 T are constructed using low-cost starting materials, standard workshop tools and only few hours of labor - an achievable project for a student or postdoc with spare time. As an application example we show how our magnet was used to polarize the nuclear spins in approximately 1 mL of pure [13C ]-methanol prior to detection of its high-resolution NMR spectrum at zero field (measurement field below 10-10 T), where signals appear at multiples of the carbon-hydrogen spin-spin coupling frequency 1JCH = 140.7 (1) Hz.
Studies of Ultracold Strontium Atoms in an Optical Dipole Trap
Traverso, A. J.; Martinez de Escobar, Y. N.; Mickelson, P. G.; Killian, T. C.
2008-05-01
We survey recent experiments with ultracold strontium performed in our group. Trapping and cooling occurs in three stages: successive magneto-optical traps (MOTs) operating on 461 nm and 689 nm transitions of strontium, respectively, are loaded to cool atoms to a temperature of 1 μK. Finally, atoms are loaded into a far-off-resonance optical dipole trap (ODT). We examine the loading characteristics, thermalization, and lifetime of atoms held within the ODT. We also perform spectroscopy of atoms held within the ODT. During laser cooling, we are able to manipulate the energy levels of the atoms and shelve them into metastable states using 707 nm and 3 μm lasers. These experiments reveal interesting physics of ultracold strontium.
Experimental study on dipole motion of an ion plasma confined in a linear Paul trap
Ito, K., E-mail: kzito@hiroshima-u.ac.jp; Okano, T.; Moriya, K.; Fukushima, K.; Higaki, H.; Okamoto, H. [Hiroshima University, Graduate School of Advanced Sciences of Matter (Japan)
2015-11-15
The compact non-neutral plasma trap systems named “S-POD” have been developed at Hiroshima University as an experimental simulator of beam dynamics. S-POD is based either on a linear Paul trap or on a Penning trap and can approximately reproduce the collective motion of a relativistic charged-particle beam observed in the center-of-mass frame. We here employ the Paul trap system to investigate the behavior of an ion plasma near a dipole resonance. A simple method is proposed to calibrate the data of secular frequency measurements by using the dipole instability condition. We also show that the transverse density profile of an ion plasma in the trap can be estimated from the time evolution of ion losses caused by the resonance.
Dipole response in neutron-rich nuclei within self-consistent approaches using realistic potentials
Lo Iudice N.
2015-01-01
Full Text Available A nucleon-nucleon chiral potential with a corrective density dependent term simulating a three-body force is used in a self-consistent calculation of the dipole strength distribution in neutron-rich nuclei, with special attention to the low-lying spectra associated to the pygmy resonance. A Hartree-Fock-Bogoliubov basis is generated and adopted in Tamm-Dancoff and random-phase approximations and, then, in an equation of motion approach which includes a basis of two-phonon states. The direct use of the mentioned chiral potential improves the description of both giant and pygmy dipole modes with respect to other realistic interactions. Moreover, the inclusion of the two-phonon states induces a pronounced fragmentation of the giant resonance and enhances the density of the low-lying levels in the pygmy region in agreement with recent experiments.
Babb, James F
2015-01-01
The dynamic electric dipole polarizability function for the magnesium atom is formed by assembling the atomic electric dipole oscillator strength distribution from combinations of theoretical and experimental data for resonance oscillator strengths and for photoionization cross sections of valence and inner shell electrons. Consistency with the oscillator strength (Thomas-Reiche-Kuhn) sum rule requires the adopted principal resonance line oscillator strength to be several percent lower than the values given in two critical tabulations, though the value adopted is consistent with a number of theoretical determinations. The static polarizability is evaluated. Comparing the resulting dynamic polarizability as a function of photon energy with more elaborate calculations reveals the contributions of inner shell electron excitations. The present results are applied to calculate the long-range interactions between two and three magnesium atoms and the interaction between a magnesium atom and a perfectly conducting m...
Foreman, Matthew R; Treasurer, Eshan; Lopez, Jehovani; Arnold, Stephen
2016-01-01
Interactions between whispering gallery modes (WGMs) and small nanoparticles are commonly modelled by treating the particle as a point dipole scatterer. This approach is assumed to be accurate as long as the nanoparticle radius, $a$, is small compared to the WGM wavelength $\\lambda$. In this article, however, we show that the large field gradients associated with the evanescent decay of a WGM causes the dipole theory to significantly underestimate the interaction strength, and hence induced WGM resonance shift, even for particles as small as $a\\sim \\lambda/10$. To mitigate this issue we employ a renormalized Born approximation to more accurately determine nanoparticle induced resonance shifts and hence enable improved particle sizing. The domain of validity of this approximation is investigated and supporting experimental results are presented.
R. A. Bosch
2006-09-01
Full Text Available In an electron storage ring, coupling between dipole and quadrupole Robinson oscillations modifies the spectrum of longitudinal beam oscillations driven by radio-frequency (rf generator phase noise. In addition to the main peak at the resonant frequency of the coupled dipole Robinson mode, another peak occurs at the resonant frequency of the coupled quadrupole mode. To describe these peaks analytically for a quadratic synchrotron potential, we include the dipole and quadrupole modes when calculating the beam response to generator noise. We thereby obtain the transfer function from generator-noise phase modulation to beam phase modulation with and without phase feedback. For Robinson-stable bunches confined in a synchrotron potential with a single minimum, the calculated transfer function agrees with measurements at the Aladdin 800-MeV electron storage ring. The transfer function is useful in evaluating phase feedback that suppresses Robinson oscillations in order to obtain quiet operation of an infrared beam line.
Dibaryon Mass and Width Calculation with Tensor Interaction
PANG Hou-Rong; PING Jia-Lun; CHEN Ling-Zhi; WANG Fan
2004-01-01
@@ The effect of tensor interaction due to gluon and Goldstone boson exchange on the dibaryon mass and decay width has been studied in the framework of the quark delocalization and colour screening model. The effective S-D wave transition interactions induced by gluon and Goldstone boson exchanges decrease quickly with the increasing channel strangeness, and there is no six-quark state in the light flavour world, which can become a bound one by the help of these tensor interactions, except for the deuteron. The K and η meson exchange effect has been shown to be negligible after a short-range truncation in this model approach. The partial D-wave decay widths, from the NΩ state to the A final states of spins 0 and 1, are 20. 7keV and 63.1 kev respectively. This is a very narrow dibaryon resonance, that might be detected in the relativistic heavy ion reaction by the existing RHIC detectors through the reconstruction of the A vertex mass and by the future COMPAS detector at CERNand the FAIR project in Germany.
The Influence of Train Leakage Currents on the LEP Dipole Field
Bravin, Enrico; Dehning, Bernd; Drees, A; Galbraith, Peter; Geitz, M A; Henrichsen, K N; Koratzinos, M; Mugnai, G
1998-01-01
The determination of the mass and the width of the Z boson at CERN's LEP accelerator, an e+e- storage ring with a circumference of approximately 27 kilometres, imposes heavy demands on the knowledge of the LEP counter-rotating electron and positron beam energies. The precision required is of the order of 1 MeV or »20 ppm frequency. Due to its size the LEP collider is influenced by various macroscopic and regional factors such as the position of the moon or seasonal changes of the rainfall in the area, as reported earlier. A new and not less surprising effect of the LEP energy was observed in 1995: railroad trains in the Geneva region perturb the dipole field. A parasitic flow of electricity, originating from the trains, travels along the LEP ground cable and the vacuum chamber, interacting with the dipole field. An account of the phenomenon with its explanation substantiated by dedicated measurements is presented.
The influence of train leakage currents on the LEP dipole field
Bravin, E.; Brun, G.; Dehning, B.; Drees, A.; Galbraith, P.; Geitz, M.; Henrichsen, K.; Koratzinos, M.; Mugnai, G.; Tonutti, M.
The determination of the mass and the width of the Z boson at CERN's LEP accelerator, an e+e- storage ring with a circumference of approximately 27 km, imposes heavy demands on the knowledge of the LEP counter-rotating electron and positron beam energies. The precision required is of the order of 1 MeV or ≈ 20 ppm. Due to its size, the LEP collider is influenced by various macroscopic and regional factors such as the position of the moon or seasonal changes of the rainfall in the area, as reported earlier. A new and not less surprising effect on the LEP energy was observed in 1995: railroad trains in the Geneva region perturb the dipole field. A parasitic flow of electricity, originating from the trains, travels along the LEP vacuum chamber, affecting the LEP dipole field. An account of the phenomenon with its explanation substantiated by dedicated measurements is presented.
Neutron electric dipole moment and possibilities of increasing accuracy of experiments
Serebrov, A. P., E-mail: serebrov@pnpi.spb.ru; Kolomenskiy, E. A.; Pirozhkov, A. N.; Krasnoshchekova, I. A.; Vasiliev, A. V.; Polyushkin, A. O.; Lasakov, M. S.; Murashkin, A. N.; Solovey, V. A.; Fomin, A. K.; Shoka, I. V.; Zherebtsov, O. M. [National Research Centre “Kurchatov Institute”, Petersburg Nuclear Physics Institute (Russian Federation); Aleksandrov, E. B.; Dmitriev, S. P.; Dovator, N. A. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Geltenbort, P.; Ivanov, S. N.; Zimmer, O. [Institut Max von Laue–Paul Langevin (France)
2016-01-15
The paper reports the results of an experiment on searching for the neutron electric dipole moment (EDM), performed on the ILL reactor (Grenoble, France). The double-chamber magnetic resonance spectrometer (Petersburg Nuclear Physics Institute (PNPI)) with prolonged holding of ultra cold neutrons has been used. Sources of possible systematic errors are analyzed, and their influence on the measurement results is estimated. The ways and prospects of increasing accuracy of the experiment are discussed.
Neutron electric dipole moment and possibilities of increasing accuracy of experiments
Serebrov, A. P.; Kolomenskiy, E. A.; Pirozhkov, A. N.; Krasnoshchekova, I. A.; Vasiliev, A. V.; Polyushkin, A. O.; Lasakov, M. S.; Murashkin, A. N.; Solovey, V. A.; Fomin, A. K.; Shoka, I. V.; Zherebtsov, O. M.; Aleksandrov, E. B.; Dmitriev, S. P.; Dovator, N. A.; Geltenbort, P.; Ivanov, S. N.; Zimmer, O.
2016-01-01
The paper reports the results of an experiment on searching for the neutron electric dipole moment (EDM), performed on the ILL reactor (Grenoble, France). The double-chamber magnetic resonance spectrometer (Petersburg Nuclear Physics Institute (PNPI)) with prolonged holding of ultra cold neutrons has been used. Sources of possible systematic errors are analyzed, and their influence on the measurement results is estimated. The ways and prospects of increasing accuracy of the experiment are discussed.
Control of the collapse of a Bose Condensate by Optical Dipole Force
付海翔; 罗有华; 李明哲; 高波; 王育竹
2003-01-01
We propose an experimental scheme of using the far-off resonance optical dipole force to control tunable collapse of Bose-Einstein condensation with attractive interactions. This scheme can conveniently alter collapse phenomena while keeping interatomic processes unchanged. Effects on the critical interaction strength and time delay are studied with numerical simulation. We show that for the blue-detuning case those two quantities are increased while for the red-detuning case they are decreased.
Alday, Luis F. [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands)]. E-mail: l.f.alday@phys.uu.nl; Boer, Jan de [Instituut voor Theoretische Fysica, Valckenierstraat 65, 1018 XE Amsterdam (Netherlands)]. E-mail: jdeboer@science.uva.nl; Messamah, Ilies [Instituut voor Theoretische Fysica, Valckenierstraat 65, 1018 XE Amsterdam (Netherlands)]. E-mail: imessama@science.uva.nl
2006-07-03
We study gravitational solutions that admit a dual CFT description and carry non-zero dipole charge. We focus on the black ring solution in AdS{sub 3}xS{sup 3} and extract from it the one-point functions of all CFT operators dual to scalar excitations of the six-dimensional metric. In the case of small black rings, characterized by the level N, angular momentum J and dipole charge q{sub 3}, we show how the large N and J dependence of the one-point functions can be reproduced, under certain assumptions, directly from a suitable ensemble in the dual CFT. Finally we present a simple toy model that describes the thermodynamics of the small black ring for arbitrary values of the dipole charge.
Dipole hearing measurements in elasmobranch fishes.
Casper, Brandon M; Mann, David A
2007-01-01
The hearing thresholds of the horn shark Heterodontus francisci and the white-spotted bamboo shark Chiloscyllium plagiosum were measured using auditory evoked potentials (AEP) in response to a dipole sound stimulus. The audiograms were similar between the two species with lower frequencies yielding lower particle acceleration thresholds. The particle acceleration audiograms showed more sensitive hearing at low frequencies than previous elasmobranch audiograms, except for the lemon shark Negaprion brevirsotris. Auditory evoked potential signals were also recorded while the dipole stimulus was moved to different locations above the head and body. The strongest AEP signals were recorded from the area around the parietal fossa, supporting previous experiments that suggested this region is important for elasmobranch hearing. This is the first time that hearing experiments have been conducted using a dipole stimulus with elasmobranchs, which more closely mimics the natural sounds of swimming prey.
Alday, L F; Messamah, I; Alday, Luis F.; Boer, Jan de; Messamah, Ilies
2006-01-01
We study gravitational solutions that admit a dual CFT description and carry non zero dipole charge. We focus on the black ring solution in AdS_3 x S^3 and extract from it the one-point functions of all CFT operators dual to scalar excitations of the six-dimensional metric. In the case of small black rings, characterized by the level N, angular momentum J and dipole charge q_3, we show how the large N and J dependence of the one-point functions can be reproduced, under certain assumptions, directly from a suitable ensemble in the dual CFT. Finally we present a simple toy model that describes the thermodynamics of the small black ring for arbitrary values of the dipole charge.
Pursuit and Synchronization in Hydrodynamic Dipoles
Kanso, Eva
2015-01-01
We study theoretically the behavior of a class of hydrodynamic dipoles. This study is motivated by recent experiments on synthetic and biological swimmers in microfluidic \\textit{Hele-Shaw} type geometries. Under such confinement, a swimmer's hydrodynamic signature is that of a potential source dipole, and the long-range interactions among swimmers are obtained from the superposition of dipole singularities. Here, we recall the equations governing the positions and orientations of interacting asymmetric swimmers in doubly-periodic domains, and focus on the dynamics of swimmer pairs. We obtain two families of `relative equilibria'-type solutions that correspond to pursuit and synchronization of the two swimmers, respectively. Interestingly, the pursuit mode is stable for large tail swimmers whereas the synchronization mode is stable for large head swimmers. These results have profound implications on the collective behavior reported in several recent studies on populations of confined microswimmers.
Photoelectron spectroscopy and the dipole approximation
Hemmers, O.; Hansen, D.L.; Wang, H. [Univ. of Nevada, Las Vegas, NV (United States)] [and others
1997-04-01
Photoelectron spectroscopy is a powerful technique because it directly probes, via the measurement of photoelectron kinetic energies, orbital and band structure in valence and core levels in a wide variety of samples. The technique becomes even more powerful when it is performed in an angle-resolved mode, where photoelectrons are distinguished not only by their kinetic energy, but by their direction of emission as well. Determining the probability of electron ejection as a function of angle probes the different quantum-mechanical channels available to a photoemission process, because it is sensitive to phase differences among the channels. As a result, angle-resolved photoemission has been used successfully for many years to provide stringent tests of the understanding of basic physical processes underlying gas-phase and solid-state interactions with radiation. One mainstay in the application of angle-resolved photoelectron spectroscopy is the well-known electric-dipole approximation for photon interactions. In this simplification, all higher-order terms, such as those due to electric-quadrupole and magnetic-dipole interactions, are neglected. As the photon energy increases, however, effects beyond the dipole approximation become important. To best determine the range of validity of the dipole approximation, photoemission measurements on a simple atomic system, neon, where extra-atomic effects cannot play a role, were performed at BL 8.0. The measurements show that deviations from {open_quotes}dipole{close_quotes} expectations in angle-resolved valence photoemission are observable for photon energies down to at least 0.25 keV, and are quite significant at energies around 1 keV. From these results, it is clear that non-dipole angular-distribution effects may need to be considered in any application of angle-resolved photoelectron spectroscopy that uses x-ray photons of energies as low as a few hundred eV.
Parameters of the best approximation of reduced neutron widths distribution. Actinides
Sukhovoj, A M
2011-01-01
The data of ENDF/B-VII library on reduced neutron widths for nuclei 231Pa, 232Th, 233,234,235,236,238U, 237Np, 239,240,241,242Pu, 241,243Am and 243Cm (including p-resonances of 232Th, 238U, 239Pu) in form of cumulative sums in function on Gamma0n/ were approximated by variable number K of partial items 0
Gorelik, ML; Urin, MH
2003-01-01
A description of basic properties (strength function, transition density, probabilities of direct nucleonic decays) of isoscalar giant monopole (including an overtone) and dipole resonances in medium-mass spherical nuclei is proposed within a semimicroscopic approach. The approach relies on employin
Cooperative Ordering in Lattices of Interacting Dipoles
Bettles, Robert J; Adams, Charles S
2014-01-01
Using classical electrodynamics simulations we investigate the cooperative behavior of regular monolayers of induced two-level dipoles, including their cooperative decays and shifts. For the particular case of the kagome lattice we observe behavior akin to EIT for lattice spacings less than the probe wavelength. Within this region the dipoles exhibit ferroelectric and anti-ferroelectric ordering. We also model how the cooperative response is manifested in the optical transmission through the kagome lattice, with sharp changes in transmission from 10% to 80% for small changes in lattice spacing.
Complete electric dipole response in 208Pb
Tamii, A; von Neumann-Cosel, P; Fujita, Y; Adachi, T; Bertulani, C A; Carter, J; Dozono, M; Fujita, H; Fujita, K; Hatanaka, K; Heilmann, A M; Ishikawa, D; Itoh, M; Ong, H J; Kawabata, T; Kalmykov, Y; Litvinova, E; Matsubara, H; Nakanishi, K; Neveling, R; Okamura, H; Özel-Tashenov, B; Ponomarev, V Yu; Richter, A; Rubio, B; Sakaguchi, H; Sakemi, Y; Sasamoto, Y; Shimbara, Y; Shimizu, Y; Smit, F D; Suzuki, T; Tameshige, Y; Wambach, J; Yamada, R; Yosoi, M; Zenihiro, J
2011-01-01
A benchmark experiment on 208Pb shows that polarized proton inelastic scattering at very forward angles including 0{\\deg} is a powerful tool for high-resolution studies of electric dipole (E1) and spin magnetic dipole (M1) modes in nuclei over a broad excitation energy range testing up-to-date nuclear model calculations. The E1 polarizability extracted from the data provides a constraint on the neutron skin thickness in 208Pb and the poorly known density dependence of the symmetry energy, relevant to the description of neutron stars.
A HTS dipole insert coil constructed
Ballarino, A; Rey, J M; Stenvall, A; Sorbi, M; Tixador, P
2013-01-01
This report is the deliverable report 7.4.1 “A HTS dipole insert coil constructed“. The report has three parts: “Design report for the HTS dipole insert”, “One insert pancake prototype coil constructed with the setup for a high field test”, and “All insert components ordered”. The three report parts show that, although the insert construction will be only completed by end 2013, all elements are present for a successful completion and that, given the important investments done by the participants, there is a full commitment of all of them to finish the project
Dipole response in 208Pb within a self-consistent multiphonon approach
Knapp, F.; Lo Iudice, N.; Veselý, P.; Andreozzi, F.; De Gregorio, G.; Porrino, A.
2015-11-01
Background: The electric dipole strength detected around the particle threshold and commonly associated with the pygmy dipole resonance offers unique information on neutron skin and symmetry energy, and is of astrophysical interest. The nature of such a resonance is still under debate. Purpose: We intend to describe the giant and pygmy resonances in 208Pb by enhancing their fragmentation with respect to the random-phase approximation. Method: We adopt the equation of motion phonon method to perform a fully self-consistent calculation in a space spanned by one-phonon and two-phonon basis states using an optimized chiral two-body potential. A phenomenological density-dependent term, derived from a contact three-body force, is added to get single-particle spectra more realistic than the ones obtained by using the chiral potential only. The calculation takes into full account the Pauli principle and is free of spurious center-of-mass admixtures. Results: We obtain a fair description of the giant resonance and obtain a dense low-lying spectrum in qualitative agreement with the experimental data. The transition densities as well as the phonon and particle-hole composition of the most strongly excited states support the pygmy nature of the low-lying resonance. Finally, we obtain realistic values for the dipole polarizability and the neutron skin radius. Conclusions: The results emphasize the role of the two-phonon states in enhancing the fragmentation of the strength in the giant resonance region and at low energy, consistently with experiments. For a more detailed agreement with the data, the calculation suggests the inclusion of the three-phonon states as well as a fine tuning of the single-particle spectrum to be obtained by a refinement of the nuclear potential.
Electromagnetic coupling in a planar periodic configuration of resonators
C. Jouvaud
2012-12-01
Full Text Available We are studying arrays composed of a periodic arrangement of sub-wavelength resonators. An analytical model is developed inside an array of 4 by 4 multi-gap split ring resonators. To describe the frequency splitting of the single fundamental resonance, we propose a simple model based on the approximation of each resonator as an electrical dipole and a magnetic dipole that are driven by the same complex amplitude. We show that the relative strength of the two dipoles strongly depends on cell symmetry. With this approximation, the dispersion relation can be obtained for an infinite size array. A simple matrix diagonalization provides a powerful way to deduce the resonant frequencies for finite size array. These results are comforted by numerical simulations. Finally, an experimental demonstration of a tunable antenna based on this study is presented.
K- nuclear states: Binding energies and widths
Hrtánková, J.; Mareš, J.
2017-07-01
K- optical potentials relevant to calculations of K- nuclear quasibound states were developed within several chiral meson-baryon coupled-channels interaction models. The applied models yield quite different K- binding energies and widths. Then the K- multinucleon interactions were incorporated by a phenomenological optical potential fitted recently to kaonic atom data. Though the applied K- interaction models differ significantly in the K-N subthreshold region, our self-consistent calculations of kaonic nuclei across the periodic table lead to conclusions valid quite generally. Due to K- multinucleon absorption in the nuclear medium, the calculated widths of K- nuclear states are sizable, ΓK-≥90 MeV, and exceed substantially their binding energies in all considered nuclei.
Radiative widths of neutral kaon excitations
Sunil V Somalwar; KTeV Collaboration
2004-03-01
We observe 147 events of the axial vector pair $K_{1} (1270) - K_{1} (1400)$ produced in the Coulomb field of a Pb target and measure the radiative widths $ (K_{1} (1400) → K^{0} + ) = 280.8 ± 23.2$ (stat.) $± (40.4)$ (syst.) keV and $ (K_{1} (1270) → K^{0} + ) = 73.2 ± 6.1$ (stat.) $± 28.3$ (syst.) keV. These first measurements are lower than the quark-model predictions. We also place upper limits on the radiative widths for $K^{*} (1410)$ and $K_{2}^{*} (1430)$ and find that the letter is very small in accord with $SU(3)$ invariance in the naive quark model.
Exotic Meson Decay Widths using Lattice QCD
Cook, M S
2006-01-01
A decay width calculation for a hybrid exotic meson h, with JPC=1-+, is presented for the channel h->pi+a1. This quenched lattice QCD simulation employs Luescher's finite box method. Operators coupling to the h and pi+a1 states are used at various levels of smearing and fuzzing, and at four quark masses. Eigenvalues of the corresponding correlation matrices yield energy spectra that determine scattering phase shifts for a discrete set of relative pi+a1 momenta. Although the phase shift data is sparse, fits to a Breit-Wigner model are attempted, resulting in a decay width of about 60 MeV when averaged over two lattice sizes.
Malberti, Martina
2006-01-01
The precision measurement of the W boson properties, such as its mass and width, constitutes an important consistency check of the Standard Model. This paper, in particular, describes methods to measure the W mass with improved precision at the Large Hadron Collider, exploiting the large number of Z bosons produced. The precision on the W boson mass achievable with an integrated luminosisty of 10~fb^-1 is discussed.
Asymmetry of Neoclassical Transport by Dipole Electric Field
王中天; 王龙
2004-01-01
Effects of dipole electric fields on neoclassical transport are studied. Large asymmetry in transport is created. The dipole fields, which are in a negative R-direction, reduce the ion drift, increase electron drift, and change the steps of excursion due to collisions. It is found that different levels of dipole field intensities have different types of transport. For the lowest level of the dipole field, the transport returns to the neoclassical one. For the highest level of the dipole field, the transport is turned to be the turbulence transport similar to the pseudo-classical transport. Experimental data may be corresponded to a large level of the dipole field intensity.
Serebrov, A. P., E-mail: serebrov@pnpi.spb.ru; Kolomenskiy, E. A.; Pirozhkov, A. N.; Krasnoshchekova, I. A.; Vasiliev, A. V.; Polyushkin, A. O.; Lasakov, M. S.; Murashkin, A. N.; Solovey, V. A.; Fomin, A. K.; Shoka, I. V.; Zherebtsov, O. M. [National Research Center Kurchatov Institute, Petersburg Nuclear Physics Institute (Russian Federation); Alexandrov, E. B.; Dmitriev, S. P.; Dovator, N. A. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Geltenbort, P.; Ivanov, S. N.; Zimmer, O. [Institut Max von Laue–Paul Langevin (France)
2015-12-15
In this work, the double chamber magnetic resonance spectrometer of the Petersburg Nuclear Physics Institute (PNPI) designed to measure the neutron electric dipole moment (EDM) is briefly described. A method for long storage of polarized ultracold neutrons in a resonance space with a superposed electric field collinear to the leading magnetic field is used. The results of the measurements carried out on the ILL reactor (Grenoble, France) are interpreted as the upper limit of the value of neutron EDM vertical bar d{sub n} vertical bar < 5.5 × 10{sup –26}e cm at the 90% confidence level.
Cooperative effects of two optical dipole antennas coupled to plasmonic Fabry-Pérot cavity.
Yang, Zhong-Jian; Wang, Qu-Quan; Lin, Hai-Qing
2012-09-07
We investigate the cooperative effects of two optical dipole antennas that are coupled to a finite Au nanowire acting as plasmonic Fabry-Pérot (F-P) cavity. The coherent coupling between one single antenna and the F-P cavity can result in Fano resonance, and the coupling strength is antenna position dependent. For two antennas coupled to the F-P cavity, constructive or destructive interference between antennas could be achieved by adjusting their positions along the F-P cavity. Consequently, the Fano resonance will become stronger or weaker correspondingly.
Are there any good digraph width measures?
Ganian, Robert; Kneis, Joachim; Meister, Daniel; Obdržálek, Jan; Rossmanith, Peter; Sikdar, Somnath
2010-01-01
Several different measures for digraph width have appeared in the last few years. However, none of them shares all the "nice" properties of treewidth: First, being \\emph{algorithmically useful} i.e. admitting polynomial-time algorithms for all $\\MS1$-definable problems on digraphs of bounded width. And, second, having nice \\emph{structural properties} i.e. being monotone under taking subdigraphs and some form of arc contractions. As for the former, (undirected) $\\MS1$ seems to be the least common denominator of all reasonably expressive logical languages on digraphs that can speak about the edge/arc relation on the vertex set.The latter property is a necessary condition for a width measure to be characterizable by some version of the cops-and-robber game characterizing the ordinary treewidth. Our main result is that \\emph{any reasonable} algorithmically useful and structurally nice digraph measure cannot be substantially different from the treewidth of the underlying undirected graph. Moreover, we introduce \\...
Varanasi, P.; Sarangi, S.
1974-01-01
Collision-broadened line widths in CO-CO2 and CO-O2 collisions have been calculated by incorporating interactions due to octopoles and hexadecapoles and short-range repulsive interactions into Anderson's (1949) theory. It is shown how these higher-order interactions can be manipulated to yield good agreement with experimental data. A critical evaluation of this totally empirical manipulation suggests that a thorough revision of the theory is required for all but simple dipole-dipole interactions. In the process of the evaluation, the values of the multipole moments are discussed.
Band structure approach to the resonant x-ray scattering
Elfimov, I. S.; Skorikov, N. A.; Anisimov, V. I.; Sawatzky, G.A.
2001-01-01
We study the resonance behaviour of the forbidden 600 and 222 x-ray Bragg peaks in Ge using LDA band structure methods. These Bragg peaks remain forbidden in the resonant dipole scattering approximation even taking into account the non local nature of the band states. However they become allowed at resonance if the eigenstates of the unoccupied conduction band involve a hybridization of p like and d like atomic states. We show that the energy dependence of the resonant behaviour, including th...
NNLL QCD Contribution of the Electromagentic Dipole Operator to \\bar B --> X_s gamma
Asatrian, H.M.; Hovhannisyan, A.; Poghosyan, V.; /Yerevan Phys. Inst.; Ewerth, T.; Greub, C.; /Bern U.; Hurth, T.; /CERN /SLAC
2006-05-16
We present an independent calculation of that part of the O({alpha}{sub s}{sup 2}) contribution to dipole operator {Omicron}{sub 7}. Using a different method, we find complete agreement mass ambiguity appearing at NLL accuracy. the complete NNLL prediction of {Lambda}({bar B} {yields} X{sub s}{gamma}) which will resolve the charm quark the decay width {Lambda}({bar B} {yields} X{sub s}{gamma}) which arises from the self-interference term of the electromagnetic with a previous calculation. This NNLL contribution is an important ingredient for
Resonant laser power build-up in ALPS-A 'light shining through a wall' experiment
Ehret, Klaus [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Frede, Maik [Laser Zentrum Hannover e.V., Hollerithallee 8, D-30419 Hannover (Germany); Ghazaryan, Samvel [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Hildebrandt, Matthias [Laser Zentrum Hannover e.V., Hollerithallee 8, D-30419 Hannover (Germany); Knabbe, Ernst-Axel [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Kracht, Dietmar [Laser Zentrum Hannover e.V., Hollerithallee 8, D-30419 Hannover (Germany); Lindner, Axel, E-mail: axel.lindner@desy.d [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany); List, Jenny [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Meier, Tobias [Max-Planck-Institute for Gravitational Physics, Albert-Einstein-Institute, and Institut fuer Gravitationsphysik, Leibniz Universitaet, Hannover, Callinstrasse 38, D-30167 Hannover (Germany); Meyer, Niels; Notz, Dieter; Redondo, Javier; Ringwald, Andreas [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Wiedemann, Guenter [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany); Willke, Benno [Max-Planck-Institute for Gravitational Physics, Albert-Einstein-Institute, and Institut fuer Gravitationsphysik, Leibniz Universitaet, Hannover, Callinstrasse 38, D-30167 Hannover (Germany)
2009-12-21
The ALPS Collaboration runs a 'light shining through a wall' (LSW) experiment to search for photon oscillations into 'weakly interacting sub-eV particles' (WISPs) inside of a superconducting HERA dipole magnet at the site of DESY. In this paper we report on the first successful integration of a large-scale optical resonant cavity to boost the available power for WISP production in this type of experiments. The key elements are a frequency tunable narrow line-width continuous wave laser acting as the primary light source and an electronic feed-back control loop to stabilize the power build-up. We describe and characterize our apparatus and demonstrate the data analysis procedures on the basis of a brief exemplary run.
LHC Dipoles: The countdown has begun
2002-01-01
One of the LHC dipole magnets has just achieved a record magnetic field of 9 Tesla in one go without quenching. The challenge now is to increase the production rate to 35 magnets a month by 2004. As a new information panel in Building 30 shows, the countdown has begun.
The isotopic dipole moment of HDO
Assafrao, Denise; Mohallem, Jose R [Laboratorio de Atomos e Moleculas Especiais, Departamento de Fisica, ICEx, Universidade Federal de Minas Gerais, CP 702, 30123-970, Belo Horizonte, MG (Brazil)
2007-03-14
An adiabatic variational approximation is used to study the monodeuterated water molecule, HDO, accounting for the isotopic effect. The isotopic dipole moment, pointing from D to H, is then calculated for the first time, yielding (1.5 {+-} 0.1) x 10{sup -3} Debye, being helpful in the interpretation of experiments. (fast track communication)
Reorientation of Defect Dipoles in Ferroelectric Ceramics
LI Bao-Shan; LI Guo-Rong; ZHAO Su-Chuan; ZHU Zhi-Gang; DING Ai-Li
2005-01-01
@@ We investigate the frequency, temperature, tetragonality and quenched temperature dependences of the hysteresis loops in Pb[(Zr0.52 Ti0.48)0.95 (Mn1/3Nb2/3)0.05]O3 (PMnN-PZT) ceramics. It has been demonstrated that the polarization-field hysteresis curves show "pinched" shapes when tested at room temperature, higher frequency or using the large-tetragonality specimen. While normal square-like loops are observed at 200 ℃ and 0.01 Hz or using the small-tetragonality one. Meanwhile, close relations between the P-E loops and the applied frequency,temperature or tetragonality reveal that there exists a typical relaxation time corresponding to the reorientation of the defect dipoles. It can be seen further from the quenched temperature dependences of the loops that the reorientation of the defect dipoles may influence the pinching. Compared to the intrinsic depinning procedure induced by changes of the distribution of defect dipoles, we provide new evidence for extrinsic depinning mechanism of the defect dipoles in the ferroelectric ceramics.
Zeroes in continuum - continuum dipole matrix elements
Obolensky, Oleg I.; Pratt, R. H.; Korol, Andrei
2003-05-01
It is well known that Cooper minima in photoeffect cross sections are due to zeroes in corresponding bound-free dipole matrix elements. As was discussed before(C. D. Shaffer, R. H. Pratt, and S. D. Oh, Phys. Rev. A. 57), 227 (1998)., free-free dipole matrix elements in screened (atomic or ionic) potentials can also have zeroes. Such zeroes (existing at energies of the order of 1-100 eV) result in structures in the energy dependence of bremsstrahlung cross sections and angular distributions(A. Florescu, O. I. Obolensky, C. D. Shaffer, and R. H. Pratt, AIP Conference Proceedings, 576), 60 (2001).. In the soft photon limit, zeroes of radiative free-free matrix elements are related to Ramsauer-Townsend minima in elastic scattering of electrons by atoms. Here we study properties of the trajectories of dipole matrix element zeroes in the plane of initial and final electron energies. We show how the trajectories in this plane evolve with ionicity for several low ℓ dipole transitions ℓ → ℓ ± 1.
Scattering properties of point dipole interactions
Zolotaryuk, Alexander; Christiansen, Peter Leth; Iermakova, S.V.
2006-01-01
dipole interactions with a renormalized coupling constant are analysed. Depending on the parameter values, all these interactions being self-adjoint extensions of the one-dimensional Schrodinger operator are shown to be divided into four types: (i) interactions will full transparency, (ii) non...
Installation of the ALICE dipole magnet
Maximilien Brice
2005-01-01
The large dipole magnet is installed on the ALICE detector at CERN. This magnet, which is cooled by demineralised water, will bend the path of muons that leave the huge rectangular solenoid (in the background). These muons are heavy electrons that interact less with matter, allowing them to traverse the main section of the detector.
A Microstrip Reflect Array Using Crossed Dipoles
Pozar, David M.; Targonski, Stephen D.
1998-01-01
Microstrip reflect arrays offer a flat profile and light weight, combined with many of the electrical characteristics of reflector antennas. Previous work [1]-[7] has demonstrated a variety of microstrip reflect arrays, using different elements at a range of frequencies. In this paper we describe the use of crossed dipoles as reflecting elements in a microstrip reflectarray. Theory of the solution will be described, with experimental results for a 6" square reflectarray operating at 28 GHz. The performance of crossed dipoles will be directly compared with microstrip patches, in terms of bandwidth and loss. We also comment on the principle of operation of reflectarray elements, including crossed dipoles, patches of variable length, and patch elements with tuning stubs. This research was prompted by the proposed concept of overlaying a flat printed reflectarray on the surface of a spacecraft solar panel. Combining solar panel and antenna apertures in this way would lead to a reduction in weight and simpler deployment, with some loss of flexibility in independently pointing the solar panel and the antenna. Using crossed dipoles as reflectarray elements will minimize the aperture blockage of the solar cells, in contrast to the use of elements such as microstrip patches.
Conceptual design of Dipole Research Experiment (DREX)
Qingmei, XIAO; Zhibin, WANG; Xiaogang, WANG; Chijie, XIAO; Xiaoyi, YANG; Jinxing, ZHENG
2017-03-01
A new terrella-like device for laboratory simulation of inner magnetosphere plasmas, Dipole Research Experiment, is scheduled to be built at the Harbin Institute of Technology (HIT), China, as a major state scientific research facility for space physics studies. It is designed to provide a ground experimental platform to reproduce the inner magnetosphere to simulate the processes of trapping, acceleration, and transport of energetic charged particles restrained in a dipole magnetic field configuration. The scaling relation of hydromagnetism between the laboratory plasma of the device and the geomagnetosphere plasma is applied to resemble geospace processes in the Dipole Research Experiment plasma. Multiple plasma sources, different kinds of coils with specific functions, and advanced diagnostics are designed to be equipped in the facility for multi-functions. The motivation, design criteria for the Dipole Research Experiment experiments and the means applied to generate the plasma of desired parameters in the laboratory are also described. Supported by National Natural Science Foundation of China (Nos. 11505040, 11261140326 and 11405038), China Postdoctoral Science Foundation (Nos. 2016M591518, 2015M570283) and Project Supported by Natural Scientific Research Innovation Foundation in Harbin Institute of Technology (No. 2017008).
Gravitational Radiation from Oscillating Gravitational Dipole
De Aquino, Fran
2002-01-01
The concept of Gravitational Dipole is introduced starting from the recent discovery of negative gravitational mass (gr-qc/0005107 and physics/0205089). A simple experiment, a gravitational wave transmitter, to test this new concept of gravitational radiation source is presented.
The SPS tunnel with a dipole magnet
1976-01-01
The SPS uses about 800 6-m long dipole magnets to bend the beam around its path. Particle beams come into the SPS from the smaller PS accelerator at 26 GeV. The SPS then accelerates the beam further up to 450 GeV when the beam is extracted and transferred to the LHC or CERN Neutrinos to Gran Sasso (CNGS).
High-resolution resonant inelastic soft X-ray scattering applied to liquids
Rubensson, Jan-Erik, E-mail: jan-erik.rubensson@fysik.uu.se [Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala (Sweden); Hennies, Franz [Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala (Sweden); MAX-lab, Lund University, Box 118, S-221 00 Lund (Sweden); Pietzsch, Annette [MAX-lab, Lund University, Box 118, S-221 00 Lund (Sweden)
2013-06-15
Highlights: ► Vibrational excitations in liquids resolved in RIXS are observed. ► Soft vibrational modes are quenched in the RIXS process. ► Intermolecular dipole–dipole interaction influences spectral features. ► Influence of room temperature is excitations observed. -- Abstract: The brilliance of modern synchrotron radiation sources and capabilities of new instrumentation facilitate resonant inelastic soft X-ray scattering of liquids and molecular materials with high spectral quality. Especially, when the energy resolution approaches the natural line widths a detailed analysis provides information about local potential surfaces, dynamic coupling between nuclear and electronic degrees of freedom, and intermolecular interactions. After briefly commenting on various sample handling systems we review the recent high-resolution RIXS results on liquid acetone. The experimental RIXS spectra excited at the O K edge demonstrate that the CO stretching mode dominates the vibrational progressions, and that softer modes are little affected by the nuclear dynamics in the intermediate state. It is shown that intermolecular coupling can be neglected in this specific case, and it is predicted that such interaction significantly broadens spectral features in liquids with larger dipole–dipole interaction. Analysis of the data further shows that initial state thermal excitations at room temperature have a noticeable influence on the spectral features.
Sajadi, Mohsen; Wolf, Martin; Kampfrath, Tobias
2017-04-01
Collective low-frequency molecular motions have large impact on chemical reactions and structural relaxation in liquids. So far, these modes have mostly been accessed indirectly by off-resonant optical pulses. Here, we provide evidence that intense terahertz (THz) pulses can resonantly excite reorientational-librational modes of aprotic and strongly polar liquids through coupling to the permanent molecular dipole moments. We observe a significantly enhanced response because the transient optical birefringence is up to an order of magnitude higher than obtained with optical excitation. Frequency-dependent measurements and a simple analytical model indicate that the enhancement arises from resonantly driven librations and their coupling to reorientational motion, assisted by the pump field and/or a cage translational mode. Our results open up the path to applications such as efficient molecular alignment, enhanced transient Kerr signals and systematic resonant nonlinear THz spectroscopy of the coupling between intermolecular modes in liquids.
Master equation with quantized atomic motion including dipole-dipole interactions
Damanet, François; Braun, Daniel; Martin, John
2016-05-01
We derive a markovian master equation for the internal dynamics of an ensemble of two-level atoms including all effects related to the quantization of their motion. Our equation provides a unifying picture of the consequences of recoil and indistinguishability of atoms beyond the Lamb-Dicke regime on both their dissipative and conservative dynamics, and is relevant for experiments with ultracold trapped atoms. We give general expressions for the decay rates and the dipole-dipole shifts for any motional states, and we find analytical formulas for a number of relevant states (Gaussian states, Fock states and thermal states). In particular, we show that the dipole-dipole interactions and cooperative photon emission can be modulated through the external state of motion. The effects predicted should be experimentally observable with Rydberg atoms. FD would like to thank the F.R.S.-FNRS for financial support. FD is a FRIA Grant holder of the Fonds de la Recherche Scientifique-FNRS.
Markert, Christina
2007-01-01
Hadronic resonances with short life times and strong coupling to the dense medium may exhibit mass shifts and width broadening as signatures of chiral symmetry restoration at the phase transition between hadronic and partonic matter. Resonances with different lifetimes are also used to extract information about the time evolution and temperature of the expanding hadronic medium. In order to collect information about the early stage (at the phase transition) of a heavy-ion collision, resonances and decay particles which are unaffected by the hadronic medium have to be used. We explore a possible new technique to extract signals from the early stage through the selection of resonances from jets. A first attempt of this analysis, using the reconstructed $\\phi$(1020) from 200 GeV Au+Au collisions in STAR, is presented.
Decoupling capabilities of split-loop resonator structure for 7 Tesla MRI surface array coils
Hurshkainen, A.; Kurdjumov, S.; Simovski, C.; Glybovski, S.; Melchakova, I.; van den Berg, C. A. T.; Raaijmakers, A.; Belov, P.
2017-09-01
In this work we studied electromagnetic properties of one-dimentional periodic structures composed of split-loop res-onators (SLRs) and investigated their capabilities in decoupling of two dipole antennas for full-body magnetic resonance imaging (MRI). Two different finite structures comprising a single-SLR and a double-SLR constitutive elements were studied. Numerical simulations of the structures were performed to evaluate their decoupling capabilities. As it was demonstrated two dipole antennas equipped with either a single or a double-SLR structure exhibit high isolation even for an electrically short distance between the dipoles. Double-SLR structure while dramatically improving isolation of the dipoles keeps the field created by each of the decoupled dipoles comparable with one of a single dipole inside the target area.
Dipole-Dipole Interaction and the Directional Motion of Brownian Motors
YU Hui; ZHAO TongJun; JI Qing; SONG YanLi; WANG YongHong; ZHAN Yong
2002-01-01
The electric field of the microtubule is calculated according to its dipole distribution. The conformationalchange of a molecular motor is described by the rotation ofa dipole which interacts with the microtubulc. The mricalsimulation for the particle current shows that this interaction helps to produce a directional motion along the microtubule.And tte average displacement executes step changes that resemble the experimental result for kinesin motors.
Helical dipole partial Siberian snake for the AGS
Takano, J [RIKEN, Saitama, (Japan); Ahrens, L A [Brookhaven National Laboratory, Upton, NY 11973 (United States); Alforque, R [Brookhaven National Laboratory, Upton, NY 11973 (United States); Bai, M [Brookhaven National Laboratory, Upton, NY 11973 (United States); Brown, K [Brookhaven National Laboratory, Upton, NY 11973 (United States); Courant, E D [Brookhaven National Laboratory, Upton, NY 11973 (United States); Ganetis, G [Brookhaven National Laboratory, Upton, NY 11973 (United States); Gardner, C J [Brookhaven National Laboratory, Upton, NY 11973 (United States); Glenn, J W [Brookhaven National Laboratory, Upton, NY 11973 (United States); Hattori, T [Tokyo Institute of Technology, Tokyo, (Japan); Huang, H [Brookhaven National Laboratory, Upton, NY 11973 (United States); Jain, A [Brookhaven National Laboratory, Upton, NY 11973 (United States); Luccio, A U [Brookhaven National Laboratory, Upton, NY 11973 (United States); MacKay, W W [Brookhaven National Laboratory, Upton, NY 11973 (United States); Okamura, M [Brookhaven National Laboratory, Upton, NY 11973 (United States); Roser, T [Brookhaven National Laboratory, Upton, NY 11973 (United States); Tsoupas, N [Brookhaven National Laboratory, Upton, NY 11973 (United States); Tepikian, S [Brookhaven National Laboratory, Upton, NY 11973 (United States); Tuozzolo, J [Brookhaven National Laboratory, Upton, NY 11973 (United States); Wood, J [Brookhaven National Laboratory, Upton, NY 11973 (United States); Zelenski, A [Brookhaven National Laboratory, Upton, NY 11973 (United States); Zeno, K [Brookhaven National Laboratory, Upton, NY 11973 (United States)
2006-11-15
Overcoming depolarization resonances in medium class synchrotrons (3 to 50 GeV) is one of the key issues in accelerating a highly polarized proton beam up to very high energies. Since such synchrotrons, including the Alternating Gradient Synchrotron (AGS) and the J-PARC Main Ring, generally do not have sufficiently long straight sections to accommodate full Siberian snakes with reasonable beam excursions, the practical solution is to use partial Siberian snakes that rotate the particle spin about a horizontal axis by a fraction of 180 degrees. For the AGS, we designed and installed a new partial Siberian snake consisting of a helical dipole magnet with a double pitch structure. The helical structure reduced the amount of transverse coupling as compared to that achieved by the previous solenoidal partial snake. This coupling led to partial depolarization at certain energies from horizontal betatron oscillations. The helical magnetic field in the snake magnet was calculated using a 3D magnetic field code TOSCA, and was optimized by segmenting the helical pitch and varying the lengths of the segments. Fabrication errors were checked and verified to be within required tolerances. Finally, the transverse field was measured by rotating harmonic coils. After installation, we achieved a 37.5% improvement in polarization - from 40% with the old solenoid to 55% with the new helical snake, thereby demonstrating that the helical partial snake is an effective device to suppress depolarization resonances in medium-sized synchrotrons.
Helical dipole partial Siberian snake for the AGS
Takano, J.; Ahrens, L. A.; Alforque, R.; Bai, M.; Brown, K.; Courant, E. D.; Ganetis, G.; Gardner, C. J.; Glenn, J. W.; Hattori, T.; Huang, H.; Jain, A.; Luccio, A. U.; MacKay, W. W.; Okamura, M.; Roser, T.; Tsoupas, N.; Tepikian, S.; Tuozzolo, J.; Wood, J.; Zelenski, A.; Zeno, K.
2006-11-01
Overcoming depolarization resonances in medium class synchrotrons (3 to 50 GeV) is one of the key issues in accelerating a highly polarized proton beam up to very high energies. Since such synchrotrons, including the Alternating Gradient Synchrotron (AGS) and the J-PARC Main Ring, generally do not have sufficiently long straight sections to accommodate full Siberian snakes with reasonable beam excursions, the practical solution is to use partial Siberian snakes that rotate the particle spin about a horizontal axis by a fraction of 180 degrees. For the AGS, we designed and installed a new partial Siberian snake consisting of a helical dipole magnet with a double pitch structure. The helical structure reduced the amount of transverse coupling as compared to that achieved by the previous solenoidal partial snake. This coupling led to partial depolarization at certain energies from horizontal betatron oscillations. The helical magnetic field in the snake magnet was calculated using a 3D magnetic field code TOSCA, and was optimized by segmenting the helical pitch and varying the lengths of the segments. Fabrication errors were checked and verified to be within required tolerances. Finally, the transverse field was measured by rotating harmonic coils. After installation, we achieved a 37.5% improvement in polarization - from 40% with the old solenoid to 55% with the new helical snake, thereby demonstrating that the helical partial snake is an effective device to suppress depolarization resonances in medium-sized synchrotrons.