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Sample records for isoscalar giant dipole

  1. Isoscalar Giant Dipole Resonance within Fermi Liquid Drop Model

    NASA Astrophysics Data System (ADS)

    Pochivalov, Oleksiy; Shlomo, Shalom

    2006-04-01

    Recent highly accurate experimental data on Isoscalar Giant Dipole (ISGDR) and Monopole (ISGMR) Resonances in nuclei renewed interest in correct microscopic description of collective excitations. Hartree-Fock based Random-Phase-Approximation (HF-RPA) is a successful method of describing collective excitations in nuclei. However, recent fully self-consistent HF-RPA calculations, which reproduce the centroid energies of the ISGMR, systematically overestimate by 1.5-2.5 MeV results for the ISGDR energy comparing with experimentally obtained data. Also, the HF-RPA model does not provide description of the widths of giant resonances. We consider these issues within the semi-classical generalization of the mean field theory, namely, Fermi-Liquid-Drop-Model (FLDM). In this presentation, we provide description of the FLDM formalism in its application to ISGDR and ISGMR calculations. We present results of FLDM calculations for centroid energy and widths of the ISGDR and ISGMR in the four nuclei, namely, 90Zr, 116Sn, 144Sm, and 208Pb and compare with available experimental data.

  2. The Isoscalar Giant Dipole Resonance in {sup 20}Pb, {sup 90}Zr and the Nuclear Compressibility

    SciTech Connect

    Yildirim, Serbulent; Koeroglu, Ulas

    2008-11-11

    The isoscalar giant dipol resonance (ISGDR) in finite nuclei is studied within the framework of a relativistic transport approach. The excitation energies of spherical {sup 90}Zr and {sup 208}Pb nuclei are obtained for different quantum hydrodynamical Lagrangian parametrization. The sensitivity of ISGDR excitation energy on the nuclear bulk to surface properties are also investigated.

  3. Isoscalar monopole and dipole excitations of cluster states and giant resonances in 12C

    NASA Astrophysics Data System (ADS)

    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.

  4. Deformation effects on isoscalar giant resonances in 24Mg

    NASA Astrophysics Data System (ADS)

    Gupta, Y. K.; Garg, U.; Hoffman, J.; Matta, J.; Rao, P. V. Madhusudhana; Patel, D.; Peach, T.; Yoshida, K.; Itoh, M.; Fujiwara, M.; Hara, K.; Hashimoto, H.; Nakanishi, K.; Yosoi, M.; Sakaguchi, H.; Terashima, S.; Kishi, S.; Murakami, T.; Uchida, M.; Yasuda, Y.; Akimune, H.; Kawabata, T.; Harakeh, M. N.

    2016-04-01

    Strength distributions for isoscalar giant resonances with multipolarity L ≤2 have been determined in 24Mg from "instrumental background-free" inelastic scattering of 386-MeV α particles at extreme forward angles, including 0∘. The isoscalar E 0 , E 1 , and E 2 strengths are observed to be 57 ±7 % , 111 .1-7.2+10.9% , and 148.6 ±7.3 % , respectively, of their energy-weighted sum rules in the excitation energy range of 6 to 35 MeV. The isoscalar giant monopole (ISGMR) and quadrupole (ISGQR) resonances exhibit a prominent K splitting which is consistent with microscopic theory for a prolate-deformed ground state of 24Mg. For the ISGQR it is due to splitting of the three K components, whereas for the ISGMR it is due to its coupling to the K =0 component of the ISGQR. Deformation effects on the isoscalar giant dipole resonance are less pronounced, however.

  5. Isoscalar dipole transition as a probe for asymmetric clustering

    NASA Astrophysics Data System (ADS)

    Chiba, Y.; Kimura, M.; Taniguchi, Y.

    2016-03-01

    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 has been unclear. Purpose: We show those resonances can be attributed to the cluster states with asymmetric configurations such as α +16O . 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 20Ne and 44Ti. 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 20Ne and 44Ti. 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 if the ground state has cluster correlation. The nuclear model calculations predict large transition matrix to the α +16O and α +40Ca cluster states comparable with or larger than the Weisskopf estimate. Conclusions: We conclude that the asymmetric cluster states are strongly excited by the isoscalar dipole transition. Combined with the isoscalar monopole transition that populates the 0+ cluster states, the isoscalar transitions are promising probes for asymmetric clusters.

  6. Isovector and isoscalar dipole excitations in 9Be and 10Be studied with antisymmetrized molecular dynamics

    NASA Astrophysics Data System (ADS)

    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 <20 MeV, exhausting about 20 % of the 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

  7. Isoscalar and isovector giant resonances in a self-consistent phonon coupling approach

    NASA Astrophysics Data System (ADS)

    Lyutorovich, N.; Tselyaev, V.; Speth, J.; Krewald, S.; Grümmer, F.; Reinhard, P.-G.

    2015-10-01

    We present fully self-consistent calculations of isoscalar giant monopole and quadrupole as well as isovector giant dipole resonances in heavy and light nuclei. The description is based on Skyrme energy-density functionals determining the static Hartree-Fock ground state and the excitation spectra within random-phase approximation (RPA) and RPA extended by including the quasiparticle-phonon coupling at the level of the time-blocking approximation (TBA). All matrix elements were derived consistently from the given energy-density functional and calculated without any approximation. As a new feature in these calculations, the single-particle continuum was included thus avoiding the artificial discretization usually implied in RPA and TBA. The step to include phonon coupling in TBA leads to small, but systematic, down shifts of the centroid energies of the giant resonances. These shifts are similar in size for all Skyrme parametrizations investigated here. After all, we demonstrate that one can find Skyrme parametrizations which deliver a good simultaneous reproduction of all three giant resonances within TBA.

  8. Evidence of Soft Dipole Resonance in 11Li with Isoscalar Character

    DOE PAGESBeta

    Kanungo, R.; Sanetullaev, A.; Jansen, Gustav R.; Tanaka, J.; Ishimoto, S.; Myo, T.; Suzuki, T.; Andreoiu, C.; Bender, P.; Chen, A. A.; et al

    2015-05-12

    The first conclusive evidence of a dipole resonance in 11Li having isoscalar character observed from inelastic scattering with a novel solid deuteron target is reported. The experiment was performed at the newly commissioned IRIS facility at TRIUMF. The results show a resonance peak at an excitation energy of 1.03±0.03 MeV with a width of 0.51±0.11 MeV (FWHM). The angular distribution is consistent with a dipole excitation in the distorted-wave Born approximation framework. The observed resonance energy together with shell model calculations show the first signature that the monopole tensor interaction is important in 11Li. The first ab initio calculations inmore » the coupled cluster framework are also included.« less

  9. Evidence of Soft Dipole Resonance in 11Li with Isoscalar Character

    SciTech Connect

    Kanungo, R.; Sanetullaev, A.; Jansen, Gustav R.; Tanaka, J.; Ishimoto, S.; Myo, T.; Suzuki, T.; Andreoiu, C.; Bender, P.; Chen, A. A.; Davids, B.; Fallis, J.; Fortin, J. P.; Galinski, N.; Gallant, A. T.; Garrett, P. E.; Hackman, G.; Hadinia, B.; Hagen, Gaute; Keefe, M.; Krucken, R.; Lighthall, J.; McNeice, E.; Miller, D.; Otsuka, T.; Purcell, J.; Randhawa, J. S.; Roger, T.; Rojas, A.; Savajols, H.; Shotter, A.; Tanihata, I.; Thompson, I. J.; Unsworth, C.; Voss, P.; Wang, Z.

    2015-05-12

    The first conclusive evidence of a dipole resonance in 11Li having isoscalar character observed from inelastic scattering with a novel solid deuteron target is reported. The experiment was performed at the newly commissioned IRIS facility at TRIUMF. The results show a resonance peak at an excitation energy of 1.03±0.03 MeV with a width of 0.51±0.11 MeV (FWHM). The angular distribution is consistent with a dipole excitation in the distorted-wave Born approximation framework. The observed resonance energy together with shell model calculations show the first signature that the monopole tensor interaction is important in 11Li. The first ab initio calculations in the coupled cluster framework are also included.

  10. Splitting of the isovector giant dipole resonance in neutron-rich spherical nuclei

    SciTech Connect

    Kolomietz, V.M.; Magner, A.G.; Shlomo, S.

    2006-02-15

    The well-known splitting of the isovector giant dipole resonance is traditionally explained as a phenomenon of the nuclear isospin asymmetry (isospin splitting model) or the nuclear deformation. We suggest a new mechanism of the splitting of the giant multipole resonances in spherical neutron-rich nuclei resulting from the interplay of the isovector and isoscalar sounds with different velocities. Our approach is based on the collisional Landau kinetic theory and can be used for description of the splitting phenomena for both the isoscalar and the isovector modes in a wide region of nuclear masses A{approx}40-240. For the isovector dipole modes, the evaluated values of the splitting energy, the relative strength of the main and satellite resonance peaks, and the contribution to the energy-weighted sum rule are in agreement with experimental data.

  11. Isoscalar giant resonance studies in a stored-beam experiment within EXL

    NASA Astrophysics Data System (ADS)

    Zamora, J. C.; Bagchi, S.; Bönig, S.; Csatlós, M.; Dillmann, I.; Dimopoulou, C.; Egelhof, P.; Eremin, V.; Furuno, T.; Geissel, H.; Gernhäuser, R.; Harakeh, M. N.; Hartig, A.-L.; Ilieva, S.; Kalantar-Nayestanaki, N.; Kiselev, O.; Kollmus, K.; Kozhuharov, C.; Krasznahorkay, A.; Kröll, T.; Kuilman, M.; Litvinov, S.; Litvinov, Yu A.; Mahjour-Shafiei, M.; Mutterer, M.; Nagae, D.; Najafi, M. A.; Nociforo, C.; Nolden, F.; Popp, U.; Rigollet, C.; Roy, S.; Scheidenberger, C.; von Schmid, M.; Steck, M.; Streicher, B.; Stuhl, L.; Thürauf, M.; Uesaka, T.; Weick, H.; Winfield, J. S.; Winters, D.; Woods, P. J.; Yamaguchi, T.; Yue, K.; Zenihiro, J.; the EXL Collaboration

    2015-11-01

    In the first campaign of the exotic nuclei studied with light-ion induced reaction in storage rings (EXL) collaboration at the existing storage ring experimental heavy-ion storage ring (ESR) at Helmholtz Center for Heavy Ion Research (GSI), we performed the first experiments using a stored beam of 58Ni and an internal helium gas-jet target aiming for the investigation of isoscalar giant resonances in inverse kinematics. In this experiment, inelastically scattered recoil particles (at very forward angles, {θ }{cm}≤slant 1°) were detected with a dedicated setup, including ultra-high vacuum (UHV)-compatible double-sided silicon strip detector (DSSDs). Preliminary results show evidence for the excitation of the isoscalar giant monopole resonance (ISGMR) in the 58Ni nucleus. This opens the opportunity to study in the near future giant resonances also with stored radioactive beams, like 56Ni, and extract important information about the nuclear matter incompressibility. In the present work the current status of the data analysis and results are shown and discussed.

  12. Fine structure of the isoscalar giant quadrupole resonance in 28Si and 27Al

    NASA Astrophysics Data System (ADS)

    Usman, I. T.; Buthelezi, Z.; Carter, J.; Cooper, G. R. J.; Fearick, R. W.; Förtsch, S. V.; Fujita, H.; Fujita, Y.; von Neumann-Cosel, P.; Neveling, R.; Papakonstantinou, P.; Pysmenetska, I.; Richter, A.; Roth, R.; Sideras-Haddad, E.; Smit, F. D.

    2016-08-01

    The isoscalar giant quadrupole resonance in 28Si and 27Al has been investigated with high-energy-resolution proton inelastic scattering at Ep=200 MeV and at scattering angles close to the maximum of Δ L =2 angular distributions with the K600 magnetic spectrometer of iThemba LABS, South Africa. Characteristic scales are extracted from the observed fine structure with a wavelet analysis and compared for 28Si with random-phase approximation and second random phase approximation calculations with an interaction derived from the Argonne V18 potential by a unitary transformation. A recent extension of the method to deformed nuclei provides the best description of the data, suggesting the significance of Landau damping.

  13. Are there nuclear structure effects on the isoscalar giant monopole resonance near A = 90?

    NASA Astrophysics Data System (ADS)

    Gupta, Yogesh; Garg, Umesh; Howard, K.; Senyigit, M.; Itoh, M.; Ando, S.; Uchiyama, A.; Aoki, T.; Iwamoto, C.; Adachi, S.; Tamii, A.; Fujiwara, M.; Kadono, C.; Akimune, H.; Matsuda, Y.; Nakahara, T.; Kawabata, T.; Tsumura, M.; Furuno, T.; Harakeh, M.; Kalantar-Nayestanaki, N.

    2015-10-01

    The excitation energy of the isoscalar giant monopole resonance (ISGMR) exhibits, in general, a very smooth behavior (Ex ~A 1 / 3) over the periodic Table. In recent work the Texas A&M group has reported that ISGMR energies for 92Zr and 92Mo are appreciably higher than that for 90Zr, suggesting significant nuclear structure effects on ISGMR and, hence, on the nuclear compressibility. We have measured inelastic scattering of 385-MeV a particles on 90,92Zr, 92Mo at extremely forward angles, including 0°, using the ``Grand Raiden'' spectrometer at RCNP, Japan. Results of detailed multipole decomposition analyses to extract the ISGMR strength distributions in the three nuclei will be presented. Supported in part by the National Science Foundation (Grant No. PHY1419765).

  14. Isoscalar response of 68Ni to α -particle and deuteron probes

    NASA Astrophysics Data System (ADS)

    Vandebrouck, M.; Gibelin, J.; Khan, E.; Achouri, N. L.; Baba, H.; Beaumel, D.; Blumenfeld, Y.; Caamaño, M.; Càceres, L.; Colò, G.; Delaunay, F.; Fernandez-Dominguez, B.; Garg, U.; Grinyer, G. F.; Harakeh, M. N.; Kalantar-Nayestanaki, N.; Keeley, N.; Mittig, W.; Pancin, J.; Raabe, R.; Roger, T.; Roussel-Chomaz, P.; Savajols, H.; Sorlin, O.; Stodel, C.; Suzuki, D.; Thomas, J. C.

    2015-08-01

    Isoscalar giant resonances have been measured in the unstable 68Ni nucleus using inelastic alpha and deuteron scattering at 50 A MeV in inverse kinematics with the active target MAYA at GANIL. Using alpha scattering, the extracted isoscalar giant monopole resonance (ISGMR) centroid was determined to be 21.1 ±1.9 MeV and the isoscalar giant quadrupole resonance (ISGQR) to be 15.9 ±1.3 MeV. Indications for soft isoscalar monopole and dipole modes are provided. Results obtained with both (α ,α' ) and (d ,d' ) probes are compatible. The evolution of isoscalar giant resonances along the Ni isotopic chain from 56Ni to 68Ni is discussed.

  15. Evidence of Soft Dipole Resonance in Li 11 with Isoscalar Character

    NASA Astrophysics Data System (ADS)

    Kanungo, R.; Sanetullaev, A.; Tanaka, J.; Ishimoto, S.; Hagen, G.; Myo, T.; Suzuki, T.; Andreoiu, C.; Bender, P.; Chen, A. A.; Davids, B.; Fallis, J.; Fortin, J. P.; Galinski, N.; Gallant, A. T.; Garrett, P. E.; Hackman, G.; Hadinia, B.; Jansen, G.; Keefe, M.; Krücken, R.; Lighthall, J.; McNeice, E.; Miller, D.; Otsuka, T.; Purcell, J.; Randhawa, J. S.; Roger, T.; Rojas, A.; Savajols, H.; Shotter, A.; Tanihata, I.; Thompson, I. J.; Unsworth, C.; Voss, P.; Wang, Z.

    2015-05-01

    The first conclusive evidence of a dipole resonance in Li 11 having isoscalar character observed from inelastic scattering with a novel solid deuteron target is reported. The experiment was performed at the newly commissioned IRIS facility at TRIUMF. The results show a resonance peak at an excitation energy of 1.03 ±0.03 MeV with a width of 0.51 ±0.11 MeV (FWHM). The angular distribution is consistent with a dipole excitation in the distorted-wave Born approximation framework. The observed resonance energy together with shell model calculations show the first signature that the monopole tensor interaction is important in Li 11 . The first ab initio calculations in the coupled cluster framework are also presented.

  16. Global investigation of the fine structure of the isoscalar giant quadrupole resonance

    SciTech Connect

    Shevchenko, A.; Burda, O.; Kalmykov, Y.; Neumann-Cosel, P. von; Ponomarev, V. Yu.; Richter, A.; Wambach, J.; Carter, J.; Sideras-Haddad, E.; Cooper, G. R. J.; Fearick, R. W.; Foertsch, S. V.; Lawrie, J. J.; Neveling, R.; Smit, F. D.; Fujita, H.; Fujita, Y.; Lacroix, D.

    2009-04-15

    Fine structure in the region of the isoscalar giant quadrupole resonance (ISGQR) in {sup 58}Ni, {sup 89}Y, {sup 90}Zr, {sup 120}Sn, {sup 166}Er, and {sup 208}Pb has been observed in high-energy-resolution ({delta}E{sub 1/2}{approx_equal}35-50 keV) inelastic proton scattering measurements at E{sub 0}=200 MeV at iThemba LABS. Calculations of the corresponding quadrupole excitation strength functions performed within models based on the random-phase approximation (RPA) reveal similar fine structure when the mixing of one-particle one-hole states with two-particle two-hole states is taken into account. A detailed comparison of the experimental data is made with results from the quasiparticle-phonon model (QPM) and the extended time-dependent Hartree-Fock (ETDHF) method. For {sup 208}Pb, additional theoretical results from second RPA and the extended theory of finite Fermi systems (ETFFS) are discussed. A continuous wavelet analysis of the experimental and the calculated spectra is used to extract dominant scales characterizing the fine structure. Although the calculations agree with qualitative features of these scales, considerable differences are found between the model and experimental results and amongst different models. Within the framework of the QPM and ETDHF calculations it is possible to decompose the model spaces into subspaces approximately corresponding to different damping mechanisms. It is demonstrated that characteristic scales mainly arise from the collective coupling of the ISGQR to low-energy surface vibrations.

  17. Giant dipole resonance in hot rotating nuclei

    NASA Astrophysics Data System (ADS)

    Chakrabarty, D. R.; Dinh Dang, N.; Datar, V. M.

    2016-05-01

    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 will be discussed along with the future outlook. The interesting phenomenon of the pre-equilibrium GDR excitation in nuclear reactions will be briefly addressed.

  18. Isoscalar compression modes within fluid dynamic approach

    SciTech Connect

    Kolomietz, V. M.; Cyclotron Institute, Texas A and M University, College Station, Texas 77843-3366 ; Shlomo, S.

    2000-06-01

    We study the nuclear isoscalar monopole and dipole compression modes in nuclei within the fluid dynamic approach (FDA) with and without the effect of relaxation. For a wide region of the medium and heavy nuclei, the FDA predicts that the isoscalar giant monopole resonance (ISGMR) and the isoscalar giant dipole resonance (ISGDR) exhaust about 90% of the corresponding model-independent sum rules. In the case of neglecting the effect of relaxation, the FDA, when adjusted to reproduce the centroid energy E0 of the ISGMR, results with centroid energy E1 of the ISGDR which is in agreement with the predictions of the self-consistent Hartree-Fock random-phase approximation calculations and the scaling model but significantly larger than the experimental value. We also show that the FDA leads to the correct hydrodynamic limit for the ratio (E1/E0){sub FDA}. We find that the ratio (E1/E0){sub FDA} depends on the relaxation time and approaches the preliminary experimental value (E1/E0){sub exp}=1.5{+-}0.1 in a short relaxation time limit. (c) 2000 The American Physical Society.

  19. Giant dipole resonances in the interacting boson model

    NASA Astrophysics Data System (ADS)

    Scholtz, F. G.; Hahne, F. J. W.

    1983-03-01

    Giant dipole resonances, represented by p bosons, are introduced into the interacting boson model. For nuclei with SU(3) symmetry the dipole is split by the interactions into two main parts, with any further fragmentation being generally small. The Raman scattering to side bands tends to be very small. This agrees with recent measurements on Er. Supported by the National Accelerator Centre, CSIR, Faure, South Africa.

  20. Electric Dipole States and Time Reversal Violation in Nuclei.

    NASA Astrophysics Data System (ADS)

    Auerbach, N.

    2016-06-01

    The nuclear Schiff moment is essential in the mechanism that induces a parity and time reversal violation in the atom. In this presentation we explore theoretically the properties and systematics of the isoscalar dipole in nuclei with the emphasis on the low-energy strength and the inverse energy weighted sum which determines the Schiff moment. We also study the influence of the isovector dipole strength distribution on the Schiff moment. The influence of a large neutron excess in nuclei is examined. The centroid energies of the isoscalar giant resonance (ISGDR) and the overtone of the isovector giant dipole resonance (OIVGDR) are given for a range of nuclei.

  1. Driving Rabi oscillations at the giant dipole resonance in xenon

    NASA Astrophysics Data System (ADS)

    Pabst, Stefan; Wang, Daochen; Santra, Robin

    2015-11-01

    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 4 d ionization threshold. We find that intensities around 1018W /cm2 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 the form of Autler-Townes splittings extending over several tens of electronvolts.

  2. Capillary-induced giant elastic dipoles in thin nematic films

    PubMed Central

    Jeridi, Haifa; Gharbi, Mohamed A.; Othman, Tahar; Blanc, Christophe

    2015-01-01

    Directed and true self-assembly mechanisms in nematic liquid crystal colloids rely on specific interactions between microparticles and the topological defects of the matrix. Most ordered structures formed in thin nematic cells are thus based on elastic multipoles consisting of a particle and nearby defects. Here, we report, for the first time to our knowledge, the existence of giant elastic dipoles arising from particles dispersed in free nematic liquid crystal films. We discuss the role of capillarity and film thickness on the dimensions of the dipoles and explain their main features with a simple 2D model. Coupling of capillarity with nematic elasticity could offer ways to tune finely the spatial organization of complex colloidal systems. PMID:26554001

  3. Capillary-induced giant elastic dipoles in thin nematic films.

    PubMed

    Jeridi, Haifa; Gharbi, Mohamed A; Othman, Tahar; Blanc, Christophe

    2015-12-01

    Directed and true self-assembly mechanisms in nematic liquid crystal colloids rely on specific interactions between microparticles and the topological defects of the matrix. Most ordered structures formed in thin nematic cells are thus based on elastic multipoles consisting of a particle and nearby defects. Here, we report, for the first time to our knowledge, the existence of giant elastic dipoles arising from particles dispersed in free nematic liquid crystal films. We discuss the role of capillarity and film thickness on the dimensions of the dipoles and explain their main features with a simple 2D model. Coupling of capillarity with nematic elasticity could offer ways to tune finely the spatial organization of complex colloidal systems. PMID:26554001

  4. Giant dipole resonance in hot and rotating nuclei

    NASA Astrophysics Data System (ADS)

    Banerjee, Sudhee R.

    2013-04-01

    The study of Giant Dipole Resonance (GDR) even after more than 60 years of its discovery, still remains an intriguing and a very relevant topic of research particularly in the case of hot and fast rotating nuclei. Many new facets of this giant collective mode of vibration are being brought to light recently owing to the new age powerful detection systems. Particularly for the nuclei with large asymmetries in its neutron and protons the study of its GDR decay modes opened up very interesting research prospects worldwide. Even with low energy light-ion and heavy-ion accelerated beams and employing the powerful large volume high energy photon spectrometer LAMBDA at VECC a number of very interesting experimental observations have been made recently which radically changes the present understanding of GDR vibrations in moderately hot nuclei in general. The availability of higher energy heavy-ion beams from the near ready superconducting cyclotron at VECC will open up many more interesting and challenging research prospects with the LAMBDA spectrometer. Exciting challenges and opportunities are also on offer for studying the properties and dynamics of hot exotic nuclei with stable and RI beams through high energy gamma decays from giant resonances. A few of the very interesting results obtained recently at VECC with the LAMBDA spectrometer, further research possibilities and several other powerful detector facilities will be discussed during the conference.

  5. Dipole-Strength Distributions up to the Giant Dipole Resonance Deduced from Photon Scattering

    NASA Astrophysics Data System (ADS)

    Schwengner, R.; Rusev, G.; Benouaret, N.; Beyer, R.; Dönau, F.; Erhard, M.; Grosse, E.; Junghans, A. R.; Kosev, K.; Klug, J.; Nair, C.; Nankov, N.; Schilling, K. D.; Wagner, A.

    2008-04-01

    Dipole-strength distributions up to the neutron-separation energies of the even-mass Mo isotopes from 92Mo to 100Mo and of the N = 50 isotones 88Sr, 89Y, 90Zr have been investigated in photon-scattering experiments using the bremsstrahlung facility at the superconducting electron accelerator ELBE of the Forschungszentrum Dresden-Rossendorf. A measurement using polarised bremsstrahlung impinging on 88Sr revealed that all resolved transitions with energies greater than 6 MeV in this nuclide except for one are E1 transitions. The intensity distributions obtained from the measured spectra after a correction for detector response and a subtraction of atomic background in the target contain a continuum part in addition to the resolved peaks. It turns out that the dipole strength in the resolved peaks amounts to about 30% of the total dipole strength while the continuum contains about 70%. In order to estimate the distribution of inelastic transitions and to correct the ground-state transitions for their branching ratios simulations of γ-ray cascades were performed. The photoabsorption cross sections obtained in this way connect smoothly to (γ, n) cross sections and give novel information about the strength on the low-energy tails of the Giant Dipole Resonances below the neutron-separation energies. The experimental cross sections are compared with predictions of a Quasiparticle-Random-Phase Approximation in a deformed basis. The calculations describe the experimentally observed increase of the dipole strengths with increasing neutron number of the Mo isotopes as a consequence of increasing nuclear deformation.

  6. Observation of isoscalar multipole strengths in exotic doubly-magic 56Ni in inelastic α scattering in inverse kinematics

    NASA Astrophysics Data System (ADS)

    Bagchi, S.; Gibelin, J.; Harakeh, M. N.; Kalantar-Nayestanaki, N.; Achouri, N. L.; Akimune, H.; Bastin, B.; Boretzky, K.; Bouzomita, H.; Caamaño, M.; Càceres, L.; Damoy, S.; Delaunay, F.; Fernández-Domínguez, B.; Fujiwara, M.; Garg, U.; Grinyer, G. F.; Kamalou, O.; Khan, E.; Krasznahorkay, A.; Lhoutellier, G.; Libin, J. F.; Lukyanov, S.; Mazurek, K.; Najafi, M. A.; Pancin, J.; Penionzhkevich, Y.; Perrot, L.; Raabe, R.; Rigollet, C.; Roger, T.; Sambi, S.; Savajols, H.; Senoville, M.; Stodel, C.; Suen, L.; Thomas, J. C.; Vandebrouck, M.; Van de Walle, J.

    2015-12-01

    The Isoscalar Giant Monopole Resonance (ISGMR) and the Isoscalar Giant Dipole Resonance (ISGDR) compression modes have been studied in the doubly-magic unstable nucleus 56Ni. They were measured by inelastic α-particle scattering in inverse kinematics at 50 MeV/u with the MAYA active target at the GANIL facility. The centroid of the ISGMR has been obtained at Ex = 19.1 ± 0.5 MeV. Evidence for the low-lying part of the ISGDR has been found at Ex = 17.4 ± 0.7 MeV. The strength distribution for the dipole mode shows similarity with the prediction from the Hartree-Fock (HF) based random-phase approximation (RPA) [1]. These measurements confirm inelastic α-particle scattering as a suitable probe for exciting the ISGMR and the ISGDR modes in radioactive isotopes in inverse kinematics.

  7. Coupled-Channel Models of Direct-Semidirect Capture via Giant-Dipole Resonances

    SciTech Connect

    Thompson, I J; Escher, Jutta E; Arbanas, Goran

    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.

  8. Coupled-Channel Models of Direct-Semidirect Capture via Giant-Dipole Resonances

    NASA Astrophysics Data System (ADS)

    Thompson, I. J.; Escher, J. E.; Arbanas, G.

    2014-04-01

    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,γ)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,γ)131Sn, the cross section of which is known to have a significant effect on nucleosynthesis models.

  9. The gamma decay of the giant dipole resonance: from zero to finite temperature

    NASA Astrophysics Data System (ADS)

    Bracco, Angela; Camera, Franco

    2016-08-01

    This paper is intended to give a selected and rather brief overview of the work made in the last thirty years to study the properties of the giant dipole resonance focusing in particular on nuclei formed at finite temperatures using heavy ion reactions. The physical problems that are discussed (using examples of particular results) in this paper can be grouped into 3 major topics: (i) the temperature dependence of the GDR width; (ii) the dipole oscillation in reaction dynamics; (iii) the isospin mixing at finite temperature.

  10. Dipole-Strength Distributions Below the Giant Dipole Resonance in the Stable Even-Mass Molybdenum Isotopes

    SciTech Connect

    Rusev, G.; Hutcheson, A. L.; Kwan, E.; Tonchev, A. P.; Tornow, W.; Angell, C. T.; Hammond, S. L.; Kawowski, H. J.; Beyer, R.; Doenau, F.; Erhard, M.; Grosse, E.; Frauendorf, S.; Junghans, A. R.; Klug, J.; Kosev, K.; Nair, C.; Nikolov, N.; Schilling, K.-D.; Schwengner, R.

    2009-03-10

    Dipole-strength distributions in the stable even-mass molybdenum isotopes up to the neutron-separation energies have been studied in photon-scattering experiments with bremsstrahlung at the superconducting electron accelerator ELBE at the Research Center Dresden-Rossendorf, Germany, and with mono-energetic photon beams at the High Intensity Gamma-ray Source facility at Triangle Universities Nuclear Laboratory. In order to determine the dipole-strength distribution, statistical methods were developed for the analysis of the measured spectra. The data obtained for the stable even-mass molybdenum isotopes from the present ({gamma},{gamma}') experiments are combined with ({gamma},n) cross sections from the literature resulting in a photoabsorption cross section covering the full range from about 4 to 15 MeV, which is of interest for nuclear structure as well as for nuclear astrophysics network calculations. Novel information about the low-energy tail of the Giant Dipole Resonance and the energy spreading of its strength is derived.

  11. Dipole-Strength Distributions Below the Giant Dipole Resonance in the Stable Even-Mass Molybdenum Isotopes

    NASA Astrophysics Data System (ADS)

    Rusev, G.; Angell, C. T.; Beyer, R.; Dönau, F.; Erhard, M.; Grosse, E.; Hammond, S. L.; Hutcheson, A. L.; Frauendorf, S.; Junghans, A. R.; Kawowski, H. J.; Kelley, J. H.; Klug, J.; Kosev, K.; Kwan, E.; Nair, C.; Nikolov, N.; Schilling, K.-D.; Schwengner, R.; Tonchev, A. P.; Tornow, W.; Wagner, A.

    2009-03-01

    Dipole-strength distributions in the stable even-mass molybdenum isotopes up to the neutron-separation energies have been studied in photon-scattering experiments with bremsstrahlung at the superconducting electron accelerator ELBE at the Research Center Dresden-Rossendorf, Germany, and with mono-energetic photon beams at the High Intensity Gamma-ray Source facility at Triangle Universities Nuclear Laboratory. In order to determine the dipole-strength distribution, statistical methods were developed for the analysis of the measured spectra. The data obtained for the stable even-mass molybdenum isotopes from the present (γ,γ') experiments are combined with (γ,n) cross sections from the literature resulting in a photoabsorption cross section covering the full range from about 4 to 15 MeV, which is of interest for nuclear structure as well as for nuclear astrophysics network calculations. Novel information about the low-energy tail of the Giant Dipole Resonance and the energy spreading of its strength is derived.

  12. Recent results on giant dipole resonance decays in highly excited nuclei

    SciTech Connect

    Snover, K.A.

    1991-12-31

    Some recent results on Giant Dipole Resonance (GDR) decays in highly excited, equilibrated nuclei, are discussed based primarily on work done at Seattle. Four sections address the following topics: oblate shapes of rotating, highly excited Zr--Mo nuclei; adiabatic versus `motionally narrowed` GDR decay; large spin-driven deformations observed in hot medium-mass nuclei; and search for entrance channel effects in GDR decay following {sup 58}Ni {plus} {sup 92}Zr fusion. 22 refs.

  13. Recent results on giant dipole resonance decays in highly excited nuclei

    SciTech Connect

    Snover, K.A.

    1991-01-01

    Some recent results on Giant Dipole Resonance (GDR) decays in highly excited, equilibrated nuclei, are discussed based primarily on work done at Seattle. Four sections address the following topics: oblate shapes of rotating, highly excited Zr--Mo nuclei; adiabatic versus motionally narrowed' GDR decay; large spin-driven deformations observed in hot medium-mass nuclei; and search for entrance channel effects in GDR decay following [sup 58]Ni [plus] [sup 92]Zr fusion. 22 refs.

  14. Properties of high-energy isoscalar monopole excitations in medium-heavy mass spherical nuclei

    SciTech Connect

    Gorelik, M. L. Shlomo, Sh. Tulupov, B. A. Urin, M. H.

    2015-07-15

    The recently developed particle-hole dispersive optical model is applied to describe properties of high-energy isoscalar monopole excitations in medium-heavy mass spherical nuclei. In particular, the double transition density averaged over the energy of the isoscalar monopole excitations is considered for {sup 208}Pb in a wide energy interval, which includes the isoscalar giant monopole resonance and its overtone. The energy-averaged strength functions of these resonances are also analyzed.

  15. Study of Collective Dipole Excitations below the Giant Dipole Resonance at HI{gamma}S

    SciTech Connect

    Tonchev, A. P.; Howell, C. R.; Tornow, W.; Angell, C.; Boswell, M.; Karwowski, H. J.; Chyzh, A.; Kelley, J. H.; Tsoneva, N.; Wu, Y. K.

    2007-02-26

    The High-Intensity Gamma-ray Source utilizing intra-cavity back-scattering of free electron laser photons from relativistic electrons allows one to produce a unique beam of high-flux gamma rays with 100% polarization and selectable energy and energy resolution which is ideal for low-energy {gamma}-ray scattering experiments. Nuclear resonance fluorescence experiments have been performed on N=82 nuclei. High sensitivity studies of E1 and M1 excitations at energies close to the neutron emission threshold have been performed. The method allows the determination of excitation energies, spin, parities, and decay branching ratios of the pygmy dipole mode of excitation. The observations are compared with calculations using statistical and quasi-particle random-phase approximations.

  16. Simplest photonuclear reactions accompanied by the excitation of isovector giant dipole and quadrupole resonances: Semimicroscopic description

    SciTech Connect

    Tulupov, B. A.; Urin, M. H.

    2012-09-15

    A semimicroscopic approach based on the continuum version of the random-phase approximation (CRPA) and on a semiphenomenological inclusion of the fragmentation effect is applied to describing cross sections for photoabsorption and direct plus semidirect and inverse reactions accompanied by the excitation of isovector giant dipole and quadrupole resonances. In addition to the spinless part of the Landau-Migdal interaction and a partly self-consistent phenomenological mean field of the nucleus, that version of the approach which is used here takes into account isovector separable velocity-dependent forces, as well as the effect of the fragmentation shift of the giant-resonance energy. The results obtained by calculating various features of the aforementioned cross sections for a number of magic and semimagic medium-mass nuclei are compared with respective experimental data.

  17. Giant permanent dipole moment of two-dimensional excitons bound to a single stacking fault

    NASA Astrophysics Data System (ADS)

    Karin, Todd; Linpeng, Xiayu; Glazov, M. M.; Durnev, M. V.; Ivchenko, E. L.; Harvey, Sarah; Rai, Ashish K.; Ludwig, Arne; Wieck, Andreas D.; Fu, Kai-Mei C.

    2016-07-01

    We investigate the magneto-optical properties of excitons bound to single stacking faults in high-purity GaAs. We find that the two-dimensional stacking fault potential binds an exciton composed of an electron and a heavy hole, and we confirm a vanishing in-plane hole g -factor, consistent with the atomic-scale symmetry of the system. The unprecedented homogeneity of the stacking-fault potential leads to ultranarrow photoluminescence emission lines (with a full width at half-maximum ≲80 μ eV ) and reveals a large magnetic nonreciprocity effect that originates from the magneto-Stark effect for mobile excitons. These measurements unambiguously determine the direction and magnitude of the giant electric dipole moment (≳e ×10 nm ) of the stacking-fault exciton, making stacking faults a promising new platform to study interacting excitonic gases.

  18. Shear-viscosity to entropy-density ratio from giant dipole resonances in hot nuclei

    SciTech Connect

    Nguyen Dinh Dang

    2011-09-15

    The Green-Kubo relation and fluctuation-dissipation theorem are employed to calculate the shear viscosity {eta} of a finite hot nucleus directly from the width and energy of the giant dipole resonance (GDR) of this nucleus. The ratio {eta}/s of shear viscosity {eta} to entropy density s is extracted from the experimental systematics of the GDR in copper, tin, and lead isotopes at finite temperature T. These empirical results are then compared with the predictions by several independent models as well as with almost model-independent estimations. Based on these results, it is concluded that the ratio {eta}/s in medium and heavy nuclei decreases with increasing temperature T to reach (1.3--4)x({h_bar}/2{pi})/(4{pi}k{sub B}) at T=5 MeV.

  19. Neutron-skin thickness from the study of the anti-analog giant dipole resonance

    SciTech Connect

    Krasznahorkay, A.; Stuhl, L.; Csatlos, M.; Algora, A.; and others

    2012-10-20

    The {gamma}-decay of the anti-analog of the giant dipole resonance (AGDR) to the isobaric analog state has been measured following the p({sup 124}Sn,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 ({Delta}R{sub pn}). By comparing the theoretical results with the measured one, the {Delta}R{sub pn} value for {sup 124}Sn 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.

  20. Measurement of giant dipole resonance width at low temperature: A new experimental perspective

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, S.; Pandit, Deepak; 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.

    2012-03-01

    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 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.

  1. Excitation and photon decay of giant resonances excited by intermediate energy heavy ions

    SciTech Connect

    Bertrand, F.E.; Beene, J.R.

    1987-01-01

    Inelastic scattering of medium energy heavy ions provides very large cross sections and peak-to-continuum ratios for excitation of giant resonances. For energies above about 50 MeV/nucleon, giant resonances are excited primarily through Coulomb excitation, which is indifferent to isospin, thus providing a good probe for the study of isovector giant resonances. The extremely large cross sections available from heavy ion excitation permit the study of rare decay modes of the giant resonances. In particular, recent measurements have been made of the photon decay of giant resonances following excitation by 22 and 84 MeV/nucleon /sup 17/O projectiles. The singles results at 84 MeV/nucleon yield peak cross sections for the isoscalar giant quadrupole resonance and the isovector giant dipole resonance of approximately 0.8 and 3 barns/sr, respectively. Data on the ground state decay of the isoscalar giant quadrupole and isovector giant dipole resonances are presented and compared with calculations. Decays to low-lying excited states are also discussed. Preliminary results from an experiment to isolate the /sup 208/Pb isovector quadrupole resonance using its gamma decay are presented. 22 refs., 19 figs., 1 tab.

  2. Dipole-dipole-induced giant Goos-Hänchen shift in a photonic crystal doped with quantum dot nanostructures

    NASA Astrophysics Data System (ADS)

    Panahi, M.; Solookinejad, G.; Ahmadi Sangachin, E.; Hossein Asadpour, Seyyed

    2016-07-01

    The impact of the dipole-dipole interaction on the Goo-Hänchen (GH) shifts in reflected and transmitted lights is investigated. A weak probe beam is incident on a cavity containing the donor and acceptor quantum dots embedded in a nonlinear photonic crystal. We deduced that the GH shifts can be easily adjusted via controlling the corresponding parameters of the system in the presence or absence of dipole-dipole interaction. Our proposed model may be useful to developing the all-optical devices based on photonic materials doped with nanoparticles.

  3. Finite amplitude method applied to the giant dipole resonance in heavy rare-earth nuclei

    NASA Astrophysics Data System (ADS)

    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.

  4. Intense {gamma}-Ray Source in the Giant-Dipole-Resonance Range Driven by 10-TW Laser Pulses

    SciTech Connect

    Giulietti, A.; Gamucci, A.; Gizzi, L. A.; Labate, L.; Bourgeois, N.; Marques, J. R.; Ceccotti, T.; Dobosz, S.; D'Oliveira, P.; Monot, P.; Popescu, H.; Reau, F.; Martin, P.; Galy, J.; Hamilton, D. J.; Giulietti, D.

    2008-09-05

    A {gamma}-ray source with an intense component around the giant dipole resonance for photonuclear absorption has been obtained via bremsstrahlung of electron bunches driven by a 10-TW tabletop laser. 3D particle-in-cell simulation proves the achievement of a nonlinear regime leading to efficient acceleration of several sequential electron bunches per each laser pulse. The rate of the {gamma}-ray yield in the giant dipole resonance region (8

  5. Intense gamma-ray source in the giant-dipole-resonance range driven by 10-TW laser pulses.

    PubMed

    Giulietti, A; Bourgeois, N; Ceccotti, T; Davoine, X; Dobosz, S; D'Oliveira, P; Galimberti, M; Galy, J; Gamucci, A; Giulietti, D; Gizzi, L A; Hamilton, D J; Lefebvre, E; Labate, L; Marquès, J R; Monot, P; Popescu, H; Réau, F; Sarri, G; Tomassini, P; Martin, P

    2008-09-01

    A gamma-ray source with an intense component around the giant dipole resonance for photonuclear absorption has been obtained via bremsstrahlung of electron bunches driven by a 10-TW tabletop laser. 3D particle-in-cell simulation proves the achievement of a nonlinear regime leading to efficient acceleration of several sequential electron bunches per each laser pulse. The rate of the gamma-ray yield in the giant dipole resonance region (8

  6. Temperature dependence of the giant dipole resonance width in 152Gd

    NASA Astrophysics Data System (ADS)

    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.

  7. Extreme nuclear shapes examined via giant dipole resonance lineshapes in hot light-mass systems

    SciTech Connect

    Pandit, Deepak; Mukhopadhyay, S.; Pal, Surajit; Bhattacharya, S.; Bhattacharya, C.; Banerjee, K.; Kundu, S.; Rana, T. K.; Dey, A.; Mukherjee, G.; Ghosh, T.; Banerjee, S. R.; De, A.; Gupta, D.

    2010-06-15

    The influence of alpha clustering on nuclear reaction dynamics is investigated using the giant dipole resonance (GDR) lineshape studies in the reactions {sup 20}Ne (E{sub lab}=145,160 MeV) + {sup 12}C and {sup 20}Ne (E{sub lab}=160 MeV) + {sup 27}Al, populating {sup 32}S and {sup 47}V, respectively. The GDR lineshapes from the two systems are remarkably different from each other. Whereas, the non-alpha-like {sup 47}V undergoes Jacobi shape transition and matches exceptionally well with the theoretical GDR lineshape estimated under the framework rotating liquid drop model (RLDM) and thermal shape fluctuation model (TSFM) signifying shape equilibration, for the alpha cluster {sup 32}S an extended prolate kind of shape is observed. This unusual deformation, seen directly via gamma decay for the first time, is predicted to be due to the formation of orbiting dinuclear configuration or molecular structure of {sup 16}O + {sup 16}O in the {sup 32}S superdeformed band.

  8. Giant dipole resonance width in nuclei near Sn at low temperature and high angular momentum

    SciTech Connect

    Bhattacharya, Srijit; Mukhopadhyay, S.; Pandit, Deepak; Pal, Surajit; Bhattacharya, S.; Bhattacharya, C.; Banerjee, K.; Kundu, S.; Rana, T. K.; Dey, A.; Mukherjee, G.; Ghosh, T.; Gupta, D.; Banerjee, S. R.

    2008-02-15

    High energy {gamma} rays in coincidence with low energy yrast {gamma} rays have been measured from {sup 113}Sb, at excitation energies of 109 and 122 MeV, formed by bombarding {sup 20}Ne on {sup 93}Nb at projectile energies of 145 and 160 MeV, respectively, to study the role of angular momentum (J) and temperature (T) over giant dipole resonance (GDR) width ({gamma}). The maximum populated angular momenta for fusion were 67({Dirac_h}/2{pi}) and 73({Dirac_h}/2{pi}), respectively, for the above-mentioned beam energies. The high energy photons were detected using a Large Area Modular BaF{sub 2} Detector Array (LAMBDA) along with a 24-element multiplicity filter. After pre-equilibrium corrections, the excitation energy E* was averaged over the decay steps of the compound nucleus (CN). The average values of temperature, angular momentum, CN mass, etc., have been calculated using the statistical model code CASCADE. Using those average values, results show the systematic increase of GDR width with T, which is consistent with Kusnezov parametrization and the thermal shape fluctuation model (TSFM). The rise of GDR width with temperature also supports the assumptions of adiabatic coupling in the TSFM. But the GDR widths and corresponding reduced plots with J are not consistent with those of the theoretical model at high spins.

  9. Giant dipole resonance width in nuclei near Sn at low temperature and high angular momentum

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Srijit; Mukhopadhyay, S.; Pandit, Deepak; Pal, Surajit; de, A.; Bhattacharya, S.; Bhattacharya, C.; Banerjee, K.; Kundu, S.; Rana, T. K.; Dey, A.; Mukherjee, G.; Ghosh, T.; Gupta, D.; Banerjee, S. R.

    2008-02-01

    High energy γ rays in coincidence with low energy yrast γ rays have been measured from Sb113, at excitation energies of 109 and 122 MeV, formed by bombarding Ne20 on Nb93 at projectile energies of 145 and 160 MeV, respectively, to study the role of angular momentum (J) and temperature (T) over giant dipole resonance (GDR) width (Γ). The maximum populated angular momenta for fusion were 67ℏ and 73ℏ, respectively, for the above-mentioned beam energies. The high energy photons were detected using a Large Area Modular BaF2 Detector Array (LAMBDA) along with a 24-element multiplicity filter. After pre-equilibrium corrections, the excitation energy E* was averaged over the decay steps of the compound nucleus (CN). The average values of temperature, angular momentum, CN mass, etc., have been calculated using the statistical model code CASCADE. Using those average values, results show the systematic increase of GDR width with T, which is consistent with Kusnezov parametrization and the thermal shape fluctuation model (TSFM). The rise of GDR width with temperature also supports the assumptions of adiabatic coupling in the TSFM. But the GDR widths and corresponding reduced plots with J are not consistent with those of the theoretical model at high spins.

  10. Excitation and photon decay of giant multipole resonances - the role and future of medium-energy heavy ions

    SciTech Connect

    Bertrand, F.E.; Beene, J.R.; Horen, D.J.

    1988-01-01

    Inelastic scattering of medium energy heavy ions provides very large cross sections and peak-to-continuum ratios for excitation of giant resonances. For energies above about 50 MeV/nucleon, giant resonances are excited primarily through Coulomb excitation, which is indifferent to isospin, thus providing a good probe for the study of isovector giant resonances. The extremely large cross sections available from heavy ion excitation permit the study of rare decay modes of the photon decay of giant resonances following excitation by 22 and 84 MeV/nucleon /sup 17/O projectiles. The singles results at 84 MeV/nucleon yield peak cross sections for the isoscalar giant quadrupole resonance and the isovector giant dipole resonance of approximately 0.8 and 3 barns/sr, respectively. Data on the ground state decay of the isoscalar giant quadrupole and isovector giant dipole resonances are presented and compared with calculations. Decays to low-lying excited states are also discussed. Preliminary results from an experiment to isolate the /sup 208/Pb isovector quadrupole resonance using its gamma decay are presented.

  11. Onset of quenching of the giant dipole resonance at high excitation energies

    NASA Astrophysics Data System (ADS)

    Santonocito, D.; Blumenfeld, Y.; Agodi, C.; Alba, R.; Bellia, G.; Coniglione, R.; Delaunay, F.; Del Zoppo, A.; Finocchiaro, P.; Hongmei, F.; Lima, V.; Maiolino, C.; Migneco, E.; Piattelli, P.; Sapienza, P.; Scarpaci, J. A.; Wieland, O.

    2014-11-01

    The evolution of the giant dipole resonance (GDR) properties in nuclei of mass A =120 to 132 has been investigated in an excitation energy range between 150 and 270 MeV through the study of complete and nearly complete fusion reactions using 116Sn beams at 17 A and 23 A MeV from the cyclotron of the Laboratorio Nazionale del Sud impinging on 12C and 24Mg targets. γ rays and light charged particles were detected using the multi-element detector array MEDEA in coincidence with evaporation residues detected by using mass and charge identification spectrometry with telescope (MACISTE). Light-charged-particle energy spectra were analyzed within the framework of a multiple-source-emission scenario by using a fitting procedure to determine the amount of pre-equilibrium emission and deduce the excitation energies reached in the compound nuclei. A detailed analysis of the γ -ray spectra and their comparison with statistical model calculations is presented. Evidence of a quenching of the GDR gamma yield was found at 270 MeV excitation energy. The quenching effect becomes progressively more important with increasing excitation energy, as observed when the comparison is extended to data from the reaction 36Ar+96Mo at 37 A MeV where hot nuclei were populated up to 430 MeV excitation energy. A coherent scenario emerges indicating the existence of a limiting excitation energy for the collective motion of about E*/A =2.1 MeV for systems of mass A =105 to 111 while a slightly lower value was observed for nuclei of mass A ˜132 . The existence of a possible link between GDR disappearance and the liquid-gas phase transition is discussed.

  12. Measurement of the {sup 241}Am({gamma},n){sup 240}Am reaction in the giant dipole resonance region

    SciTech Connect

    Tonchev, A. P.; Howell, C. R.; Hutcheson, A.; Kwan, E.; Raut, R.; Rusev, G.; Tornow, W.; Hammond, S. L.; Huibregtse, C.; Kelley, J. H.; Kawano, T.; Vieira, D. J.; Wilhelmy, J. B.

    2010-11-15

    The photodisintegration cross section of the radioactive nucleus {sup 241}Am has been obtained using activation techniques and monoenergetic {gamma}-ray beams from the HI{gamma}S facility. The induced activity of {sup 240}Am produced via the {sup 241}Am({gamma},n) reaction was measured in the energy interval from 9 to 16 MeV utilizing high-resolution {gamma}-ray spectroscopy. The experimental data for the {sup 241}Am({gamma},n) reaction in the giant dipole resonance energy region are compared with statistical nuclear-model calculations.

  13. Probing nuclear shapes close to the fission limit with the giant dipole resonance in {sup 216}Rn

    SciTech Connect

    Kmiecik, M.; Maj, A.; Brekiesz, M.; Krolas, W.; Meczynski, W.; Styczen, J.; Zieblinski, M.; Million, B.; Bracco, A.; Camera, F.; Benzoni, G.; Leoni, S.; Wieland, O.; Brambilla, S.; Herskind, B.; Kicinska-Habior, M.; Dubray, N.; Dudek, J.; Schunck, N.

    2004-12-01

    The gamma-ray decay of the giant dipole resonance (GDR) in the compound nucleus {sup 216}Rn formed with the reaction {sup 18}O+{sup 198}Pt at the bombarding energy of 96 MeV was investigated. High-energy gamma-ray spectra in coincidence with both prompt and delayed low-energy transitions were measured. The obtained GDR width at the average temperature {approx_equal}1 MeV was found to be larger than that at T=0 MeV and to be approximately constant as a function of spin. The measured width value of 7 MeV is found to be consistent with the predictions based on calculations of the nuclear shape distribution using the newest approach for the treatment of the fission barrier within the liquid drop model. The present study is the first investigation of the giant dipole resonance width from the fusion-evaporation decay channel in this nuclear mass range.

  14. Giant dipole resonance built on hot rotating nuclei produced during evaporation of light particles from the 88Mo compound nucleus

    NASA Astrophysics Data System (ADS)

    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.

  15. Heavy ion Coulomb excitation and gamma decay studies of the one and two phonon giant dipole resonances in {sup 208}Pb and {sup 209}Bi

    SciTech Connect

    Mueller, P.E.; Beene, J.R.; Bertrand, F.E.

    1993-12-01

    Projectile -- photon coincidences were measured for the scattering of an 80 MeV/nucleon {sup 64}Zn beam from {sup 208}Pb and {sup 209}Bi targets at the GANIL heavy ion accelerator facility. Projectile-like particles between 0.5{degrees} and 4.5{degrees} relative to the incident beam direction were detected in the SPEG energy loss spectrometer where their momentum, charge, and mass were determined. Photons were detected in the BaF{sub 2} scintillation detector array TAPS. Light charged particles produced in the reaction were detected in the KVI Forward Wall. The analysis of the data acquired in this experiment is focused on three different phenomena: (1) the two phonon giant dipole resonance, (2) time dependence of the decay of the one phonon giant dipole resonance, and (3) giant resonance strength in projectile nuclei.

  16. Evolution of the pygmy dipole resonance in nuclei with neutron excess

    SciTech Connect

    Co', G.; Donno, V. De; Maieron, C.; Anguiano, M.; Lallena, A. M.

    2009-07-15

    The electric dipole excitation of various nuclei is calculated with a Random Phase Approximation phenomenological approach. The evolution of the strength distribution in various groups of isotopes of oxygen, calcium, zirconium, and tin is studied. The neutron excess produces E1 strength in the low-energy region. Indexes to measure the collectivity of the excitation are defined. We studied the behavior of proton and neutron transition densities to determine the isoscalar or isovector nature of the excitation. We observed that in medium-heavy nuclei the low-energy E1 excitation has characteristics rather different than those exhibited by the giant dipole resonance. This new type of excitation can be identified as a pygmy dipole resonance.

  17. Information Content of the Low-Energy Electric Dipole Strength: Correlation Analysis

    SciTech Connect

    Reinhard, P.-G.; Nazarewicz, Witold

    2013-01-01

    Background: Recent experiments on the electric dipole (E1) polarizability in heavy nuclei have stimulated theoretical interest in the low-energy electric dipole strength, both isovector and isoscalar. Purpose: We study the information content carried by the electric dipole strength with respect to isovector and isoscalar indicators characterizing bulk nuclear matter and finite nuclei. To separate isoscalar and isovector modes, and low-energy strength and giant resonances, we analyze the E1 strength as a function of the excitation energy E and momentum transfer q. Methods: We use the self-consistent nuclear density functional theory with Skyrme energy density functionals, augmented by the random phase approximation, to compute the E1 strength and covariance analysis to assess correlations between observables. Calculations are performed for the spherical, doubly magic nuclei 208Pb and 132Sn. Results: We demonstrate that E1 transition densities in the low-energy region below the giant dipole resonance exhibit appreciable state dependence and multinodal structures, which are fingerprints of weak collectivity. The correlation between the accumulated low-energy strength and the symmetry energy is weak, and dramatically depends on the energy cutoff assumed. On the other hand, a strong correlation is predicted between isovector indicators and the accumulated isovector strength at E around 20 MeV and momentum transfer q 0.65 fm 1. Conclusions: Momentum- and coordinate-space patterns of the low-energy dipole modes indicate a strong fragmentation into individual particle-hole excitations. The global measure of low-energy dipole strength correlates poorly with the nuclear symmetry energy and other isovector characteristics. Consequently, our results do not support the suggestion that there exists a collective pygmy dipole resonance, which is a strong indicator of nuclear isovector properties. By considering nonzero values of momentum transfer, one can isolate individual

  18. TESTING CONVECTIVE-CORE OVERSHOOTING USING PERIOD SPACINGS OF DIPOLE MODES IN RED GIANTS

    SciTech Connect

    Montalban, J.; Noels, A.; Dupret, M.-A.; Scuflaire, R.; Miglio, A.; Ventura, P.

    2013-04-01

    Uncertainties on central mixing in main-sequence (MS) and core He-burning (He-B) phases affect key predictions of stellar evolution such as late evolutionary phases, chemical enrichment, ages, etc. We propose a test of the extension of extra-mixing in two relevant evolutionary phases based on period spacing ({Delta}P) of solar-like oscillating giants. From stellar models and their corresponding adiabatic frequencies (respectively, computed with ATON and LOSC codes), we provide the first predictions of the observable {Delta}P for stars in the red giant branch and in the red clump (RC). We find (1) a clear correlation between {Delta}P and the mass of the helium core (M{sub He}); the latter in intermediate-mass stars depends on the MS overshooting, and hence it can be used to set constraints on extra-mixing during MS when coupled with chemical composition; and (2) a linear dependence of the average value of the asymptotic period spacing (({Delta}P){sub a}) on the size of the convective core during the He-B phase. A first comparison with the inferred asymptotic period spacing for Kepler RC stars also suggests the need for extra-mixing during this phase, as evinced from other observational facts.

  19. Constraints on the neutron skin and symmetry energy from the anti-analog giant dipole resonance in 208Pb

    NASA Astrophysics Data System (ADS)

    Cao, Li-Gang; Roca-Maza, X.; Colò, G.; Sagawa, H.

    2015-09-01

    We investigate the impact of the neutron skin thickness, Δ Rn p , on the energy difference between the anti-analog giant dipole resonance (AGDR), EAGDR, and the isobaric analog state (IAS), EIAS, 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 EAGDR-EIAS with Δ Rn p . 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 approach and we can compare our results with available experimental data in 208Pb in order to extract a preferred value for Δ Rn p and, in turn, for the symmetry energy parameters. Averaging the results from two available experimental data, our analysis gives Δ Rn p = 0.236 ±0.018 fm, J = 33.2 ±1.0 MeV, and a slope parameter of the symmetry energy at saturation L = 97.3 ±11.2 MeV. The errors include the experimental uncertainties and a lower-limit estimate of model uncertainties. These results are consistent with those extracted from different experimental data albeit L and Δ Rn p are somewhat large when compared to previous estimations based on giant resonance studies. Possible hints whether model dependence can explain this difference are provided.

  20. Giant Dipole Resonance in the hot and thermalized 132Ce nucleus: damping of collective modes at finite temperature

    SciTech Connect

    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.

  1. Description of the dipole giant resonance in heavy and superheavy nuclei within Skyrme random-phase approximation

    SciTech Connect

    Kleinig, W.; Nesterenko, V. O.; Kvasil, J.; Vesely, P.; Reinhard, P.-G.

    2008-10-15

    The E1(T=1) isovector dipole giant resonance (GDR) in heavy and superheavy deformed nuclei is analyzed over a sample of 18 rare-earth nuclei, four actinides, and three chains of superheavy elements (Z=102, 114, and 120). The basis of the description is the self-consistent separable random-phase approximation (SRPA) using the Skyrme force SLy6. The model well reproduces the experimental data in the rare-earth and actinide regions. The trend of the resonance peak energies follows the estimates from collective models, showing a bias to the volume mode for the rare-earth isotopes and a mix of volume and surface modes for actinides and superheavy elements. The widths of the GDR are mainly determined by the Landau fragmentation, which in turn is found to be strongly influenced by deformation. A deformation splitting of the GDR can contribute to about one-third of the width, and about 1 MeV further broadening can be associated with mechanisms beyond the SRPA description (e.g., escape widths and coupling with complex configurations)

  2. Calculations of the giant-dipole-resonance photoneutrons using a coupled EGS4-morse code

    SciTech Connect

    Liu, J.C.; Nelson, W.R.; Kase, K.R.; Mao, X.S.

    1995-10-01

    The production and transport of the photoneutrons from the giant-dipoleresonance reaction have been implemented in a coupled EGS4-MORSE code. The total neutron yield (including both the direct neutron and evaporation neutron components) is calculated by folding the photoneutron yield cross sections with the photon track length distribution in the target. Empirical algorithms based on the measurements have been developed to estimate the fraction and energy of the direct neutron component for each photon. The statistical theory in the EVAP4 code, incorporated as a MORSE subroutine, is used to determine the energies of the evaporation neutrons. These represent major improvements over other calculations that assumed no direct neutrons, a constant fraction of direct neutrons, monoenergetic direct neutron, or a constant nuclear temperature for the evaporation neutrons. It was also assumed that the slow neutrons (< 2.5 MeV) are emitted isotropically and the fast neutrons are emitted anisotropically in the form of 1+Csin{sup 2}{theta}, which have a peak emission at 900. Comparisons between the calculated and the measured photoneutron results (spectra of the direct, evaporation and total neutrons; nuclear temperatures; direct neutron fractions) for materials of lead, tungsten, tantalum and copper have been made. The results show that the empirical algorithms, albeit simple, can produce reasonable results over the interested photon energy range.

  3. Role of deformation on giant resonances within the quasiparticle random-phase approximation and the Gogny force

    SciTech Connect

    Peru, S.; Goutte, H.

    2008-04-15

    Fully consistent axially-symmetric-deformed quasiparticle random phase approximation (QRPA) calculations have been performed, in which the same Gogny D1S effective force has been used for both the Hartree-Fock-Bogolyubov mean field and the QRPA approaches. Giant resonances calculated in deformed {sup 26-28}Si and {sup 22-24}Mg nuclei as well as in the spherical {sup 30}Si and {sup 28}Mg isotopes are presented. Theoretical results for isovector-dipole and isoscalar monopole, quadrupole, and octupole responses are presented and the impact of the intrinsic nuclear deformation is discussed.

  4. Excited light isoscalar mesons from lattice QCD

    SciTech Connect

    Christopher Thomas

    2011-07-01

    I report a recent lattice QCD calculation of an excited spectrum of light isoscalar mesons, something that has up to now proved challenging for lattice QCD. With novel techniques we extract an extensive spectrum with high statistical precision, including spin-four states and, for the first time, light isoscalars with exotic quantum numbers. In addition, the hidden flavour content of these mesons is determined, providing a window on annihilation dynamics in QCD. I comment on future prospects including applications to the study of resonances.

  5. Quantitatively analyzing the mechanism of giant circular dichroism in extrinsic plasmonic chiral nanostructures by tracking the interplay of electric and magnetic dipoles

    NASA Astrophysics Data System (ADS)

    Hu, Li; Tian, Xiaorui; Huang, Yingzhou; Fang, Liang; Fang, Yurui

    2016-02-01

    Plasmonic chirality has drawn much attention because of tunable circular dichroism (CD) and the enhancement for chiral molecule signals. Although various mechanisms have been proposed to explain the plasmonic CD, a quantitative explanation like the ab initio mechanism for chiral molecules, is still unavailable. In this study, a mechanism similar to the mechanisms associated with chiral molecules was analyzed. The giant extrinsic circular dichroism of a plasmonic splitting rectangle ring was quantitatively investigated from a theoretical standpoint. The interplay of the electric and magnetic modes of the meta-structure is proposed to explain the giant CD. We analyzed the interplay using both an analytical coupled electric-magnetic dipole model and a finite element method model. The surface charge distributions showed that the circular current yielded by the splitting rectangle ring causes the ring to behave like a magneton at some resonant modes, which then interact with the electric modes, resulting in a mixing of the two types of modes. The strong interplay of the two mode types is primarily responsible for the giant CD. The analysis of the chiral near-field of the structure shows potential applications for chiral molecule sensing.Plasmonic chirality has drawn much attention because of tunable circular dichroism (CD) and the enhancement for chiral molecule signals. Although various mechanisms have been proposed to explain the plasmonic CD, a quantitative explanation like the ab initio mechanism for chiral molecules, is still unavailable. In this study, a mechanism similar to the mechanisms associated with chiral molecules was analyzed. The giant extrinsic circular dichroism of a plasmonic splitting rectangle ring was quantitatively investigated from a theoretical standpoint. The interplay of the electric and magnetic modes of the meta-structure is proposed to explain the giant CD. We analyzed the interplay using both an analytical coupled electric-magnetic dipole

  6. Splitting of the Pygmy Dipole Resonance

    NASA Astrophysics Data System (ADS)

    Endres, J.; Butler, P.; Harakeh, M. N.; Harissopulos, S.; Herzberg, R.-D.; Krücken, R.; Lagoyannis, A.; Litvinova, E.; Pietralla, N.; Ponomarev, V. Yu.; Popescu, L.; Ring, P.; Savran, D.; Scheck, M.; Sonnabend, K.; Stoica, V. I.; Wörtche, H. J.; Zilges, A.

    2011-10-01

    In recent years investigations have been made to study the electric Pygmy Dipole Resonance (PDR) systematically, mainly in semi-magic nuclei. For this purpose the well understood high resolution (γ,γ') photon scattering method is used. In complementary (α,α'γ) coincidence experiments at Eα = 136 MeV a similar γ-energy resolution and a high selectivity to E1 transitions can be obtained at the Big-Bite Spectrometer (BBS) at KVI, Groningen. In comparison to the (γ,γ') method a structural splitting of the PDR is observed in the N = 82 nuclei 138Ba and 140Ce and in the Z = 50 nucleus 124Sn. The low energy part is excited in (γ,γ') as well as in (α,α'γ) while the high energy part is observed in (γ,γ') only. The experimental results together with theoretical QPM and RQTBA calculations on 124Sn which are able to reproduce the splitting of the PDR qualitatively are presented. The low-lying group of Jπ = 1- states seem to represent the more isoscalar neutron-skin oscillation of the PDR while the energetically higher-lying states seemingly belong to the transitional region between the PDR and the isovector Giant Dipole Resonance (IVGDR).

  7. Splitting of the Pygmy Dipole Resonance

    SciTech Connect

    Endres, J.; Zilges, A.; Butler, P.; Herzberg, R.-D.; Scheck, M.; Harakeh, M. N.; Harissopulos, S.; Lagoyannis, A.; Kruecken, R.; Ring, P.; Litvinova, E.; Pietralla, N.; Ponomarev, V. Yu.; Sonnabend, K.; Popescu, L.; Savran, D.; Stoica, V. I.; Woertche, H. J.

    2011-10-28

    In recent years investigations have been made to study the electric Pygmy Dipole Resonance (PDR) systematically, mainly in semi-magic nuclei. For this purpose the well understood high resolution ({gamma},{gamma}') photon scattering method is used. In complementary ({alpha},{alpha}'{gamma}) coincidence experiments at E{sub {alpha}} = 136 MeV a similar {gamma}-energy resolution and a high selectivity to E1 transitions can be obtained at the Big-Bite Spectrometer (BBS) at KVI, Groningen. In comparison to the ({gamma},{gamma}') method a structural splitting of the PDR is observed in the N = 82 nuclei {sup 138}Ba and {sup 140}Ce and in the Z = 50 nucleus {sup 124}Sn. The low energy part is excited in ({gamma},{gamma}') as well as in ({alpha},{alpha}'{gamma}) while the high energy part is observed in ({gamma},{gamma}') only. The experimental results together with theoretical QPM and RQTBA calculations on {sup 124}Sn which are able to reproduce the splitting of the PDR qualitatively are presented. The low-lying group of J{sup {pi}} = 1{sup -} states seem to represent the more isoscalar neutron-skin oscillation of the PDR while the energetically higher-lying states seemingly belong to the transitional region between the PDR and the isovector Giant Dipole Resonance (IVGDR).

  8. Low-energy tail of the giant dipole resonance in Mo98 and Mo100 deduced from photon-scattering experiments

    NASA Astrophysics Data System (ADS)

    Rusev, G.; Schwengner, R.; Dönau, F.; Erhard, M.; Grosse, E.; Junghans, A. R.; Kosev, K.; Schilling, K. D.; Wagner, A.; Bečvář, F.; Krtička, M.

    2008-06-01

    Dipole-strength distributions in the nuclides Mo98 and Mo100 up to the neutron-separation energies have been studied in photon-scattering experiments at the bremsstrahlung facility of the Forschungszentrum Dresden-Rossendorf. To determine the dipole-strength distributions up to the neutron-emission thresholds, statistical methods were developed for the analysis of the measured spectra. The measured spectra of scattered photons were corrected for detector response and atomic background by simulations using the code GEANT3. Simulations of γ-ray cascades were performed to correct the intensities of the transitions to the ground state for feeding from higher-lying levels and to determine their branching ratios. The photoabsorption cross sections obtained for Mo98 and Mo100 from the present (γ,γ') experiments are combined with (γ,n) data from literature, resulting in a photoabsorption cross section covering the range from 4 to about 15 MeV of interest for network calculations in nuclear astrophysics. Novel information about the low-energy tail of the giant dipole resonance and its energy dependence is derived. The photoabsorption cross sections deduced from the present photon-scattering experiments are compared with existing data from neutron capture and He3-induced reactions.

  9. Quantitatively analyzing the mechanism of giant circular dichroism in extrinsic plasmonic chiral nanostructures by tracking the interplay of electric and magnetic dipoles.

    PubMed

    Hu, Li; Tian, Xiaorui; Huang, Yingzhou; Fang, Liang; Fang, Yurui

    2016-02-14

    Plasmonic chirality has drawn much attention because of tunable circular dichroism (CD) and the enhancement for chiral molecule signals. Although various mechanisms have been proposed to explain the plasmonic CD, a quantitative explanation like the ab initio mechanism for chiral molecules, is still unavailable. In this study, a mechanism similar to the mechanisms associated with chiral molecules was analyzed. The giant extrinsic circular dichroism of a plasmonic splitting rectangle ring was quantitatively investigated from a theoretical standpoint. The interplay of the electric and magnetic modes of the meta-structure is proposed to explain the giant CD. We analyzed the interplay using both an analytical coupled electric-magnetic dipole model and a finite element method model. The surface charge distributions showed that the circular current yielded by the splitting rectangle ring causes the ring to behave like a magneton at some resonant modes, which then interact with the electric modes, resulting in a mixing of the two types of modes. The strong interplay of the two mode types is primarily responsible for the giant CD. The analysis of the chiral near-field of the structure shows potential applications for chiral molecule sensing. PMID:26814829

  10. Measurement of the isoscalar monopole response in the neutron-rich nucleus 68Ni.

    PubMed

    Vandebrouck, M; Gibelin, J; Khan, E; Achouri, N L; Baba, H; Beaumel, D; Blumenfeld, Y; Caamaño, M; Càceres, L; Colò, G; Delaunay, F; Fernandez-Dominguez, B; Garg, U; Grinyer, G F; Harakeh, M N; Kalantar-Nayestanaki, N; Keeley, N; Mittig, W; Pancin, J; Raabe, R; Roger, T; Roussel-Chomaz, P; Savajols, H; Sorlin, O; Stodel, C; Suzuki, D; Thomas, J C

    2014-07-18

    The isoscalar monopole response has been measured in the unstable nucleus (68)Ni using inelastic alpha scattering at 50A  MeV in inverse kinematics with the active target MAYA at GANIL. The isoscalar giant monopole resonance (ISGMR) centroid was determined to be 21.1 ± 1.9 MeV and indications for a soft monopole mode are provided for the first time at 12.9 ± 1.0 MeV. Analysis of the corresponding angular distributions using distorted-wave-born approximation with random-phase approximation transition densities indicates that the L = 0 multipolarity dominates the cross section for the ISGMR and significantly contributes to the low-energy mode. The L=0 part of this low-energy mode, the soft monopole mode, is dominated by neutron excitations. This demonstrates the relevance of inelastic alpha scattering in inverse kinematics in order to probe both the ISGMR and isoscalar soft modes in neutron-rich nuclei. PMID:25083638

  11. Measurement of the Isoscalar Monopole Response in the Neutron-Rich Nucleus Ni68

    NASA Astrophysics Data System (ADS)

    Vandebrouck, M.; Gibelin, J.; Khan, E.; Achouri, N. L.; Baba, H.; Beaumel, D.; Blumenfeld, Y.; Caamaño, M.; Càceres, L.; Colò, G.; Delaunay, F.; Fernandez-Dominguez, B.; Garg, U.; Grinyer, G. F.; Harakeh, M. N.; Kalantar-Nayestanaki, N.; Keeley, N.; Mittig, W.; Pancin, J.; Raabe, R.; Roger, T.; Roussel-Chomaz, P.; Savajols, H.; Sorlin, O.; Stodel, C.; Suzuki, D.; Thomas, J. C.

    2014-07-01

    The isoscalar monopole response has been measured in the unstable nucleus Ni68 using inelastic alpha scattering at 50A MeV in inverse kinematics with the active target MAYA at GANIL. The isoscalar giant monopole resonance (ISGMR) centroid was determined to be 21.1±1.9 MeV and indications for a soft monopole mode are provided for the first time at 12.9±1.0 MeV. Analysis of the corresponding angular distributions using distorted-wave-born approximation with random-phase approximation transition densities indicates that the L =0 multipolarity dominates the cross section for the ISGMR and significantly contributes to the low-energy mode. The L=0 part of this low-energy mode, the soft monopole mode, is dominated by neutron excitations. This demonstrates the relevance of inelastic alpha scattering in inverse kinematics in order to probe both the ISGMR and isoscalar soft modes in neutron-rich nuclei.

  12. Measurement of the Isoscalar Monopole Response in the Neutron-Rich Nucleus 68Ni using the Active Target MAYA

    NASA Astrophysics Data System (ADS)

    Vandebrouck, M.; Gibelin, J.; Khan, E.; Achouri, N. L.; Baba, H.; Beaumel, D.; Blumenfeld, Y.; Caamaño, M.; Càceres, L.; Colò, G.; Delaunay, F.; Fernandez-Dominguez, B.; Garg, U.; Grinyer, G. F.; Harakeh, M. N.; Kalantar-Nayestanaki, N.; Keeley, N.; Mittig, W.; Pancin, J.; Raabe, R.; Roger, T.; Roussel-Chomaz, P.; Savajols, H.; Sorlin, O.; Stodel, C.; Suzuki, D.; Thomas, J. C.

    We report the measurement of the isoscalar monopole strength in the unstable nucleus 68Ni using inelastic alpha scattering at 50A MeV in inverse kinematics. This experiment has been performed at GANIL with LISE spectrometer using a dedicated detector: the active target MAYA. A part of the isoscalar giant monopole resonance (ISGMR) has been measured at 21.1 ± 1.9 MeV and indications for a soft monopole mode are provided for the first time at 12.9 ± 1.0 MeV. Distorted-wave born approximation (DWBA) with random-phase approximation (RPA) transition densities have been used to study angular distribution and indicate that the L = 0 multipolarity dominates the cross-section for the ISGMR, and significantly contributes to the soft mode.

  13. Study of the soft dipole modes in 140Ce via inelastic scattering of 17O

    NASA Astrophysics Data System (ADS)

    Krzysiek, M.; Kmiecik, M.; Maj, A.; Bednarczyk, P.; Ciemała, M.; Fornal, B.; Grȩbosz, J.; Mazurek, K.; Mȩczyński, W.; Ziȩbliński, M.; Crespi, F. C. L.; Bracco, A.; Benzoni, G.; Blasi, N.; Boiano, C.; Bottoni, S.; Brambilla, S.; Camera, F.; Giaz, A.; Leoni, S.; Million, B.; Morales, A. I.; Nicolini, R.; Pellegri, L.; Riboldi, S.; Vandone, V.; Wieland, O.; De Angelis, G.; Napoli, D. R.; Valiente-Dobon, J. J.; Bazzacco, D.; Farnea, E.; Gottardo, A.; Lenzi, S.; Lunardi, S.; Mengoni, D.; Michelagnoli, C.; Recchia, F.; Ur, C.; Gadea, A.; Huyuk, T.; Barrientos, D.; Birkenbach, B.; Geibel, K.; Hess, H.; Reiter, P.; Steinbach, T.; Wiens, A.; Bürger, A.; Görgen, A.; Guttormsen, M.; Larsen, A. C.; Siem, S.

    2014-05-01

    The main aim of this study was a deeper understanding of the nuclear structure properties of the soft dipole modes in 140Ce, excited via inelastic scattering of weakly bound 17O projectiles. An important aim was to investigate the ‘splitting’ of the PDR into two parts: a low-energy isoscalar component dominated by neutron-skin oscillations and a higher-energy component lying on the tail of the giant dipole resonance of a rather isovector character. This was already observed for this nucleus, investigated in (α, α‧) and (γ, γ‧) experiments. The experiment was performed at Laboratori Nazionali di Legnaro, Italy. Inelastic scattering of 17O ion beam at 20 MeV A-1 was used to excite the resonance modes in the 140Ce target. Gamma-rays were registered by five triple clusters of AGATA-Demonstrator and nine large volume scintillators (LaBr3). The scattered 17O ions were identified by two ΔE - E Si telescopes of the TRACE array mounted inside the scattering chamber. The telescopes consisted of two segmented Si-pad detectors, each of 60 pixels. Very preliminary data have shown a strong domination of the E1 transitions in the ‘pygmy’ region with a character more similar to the one obtained in alpha scattering experiment.

  14. Pygmy dipole resonance and dipole polarizability in {sup 90}Zr

    SciTech Connect

    Iwamoto, C.; Tamii, A.; Shima, T.; Hashimoto, T.; Suzuki, T.; Fujita, H.; Hatanaka, K.; Utsunomiya, H.; Akimune, H.; Yamagata, T.; Okamoto, A.; Kondo, T.; Nakada, H.; Kawabata, T.; Fujita, Y.; Matsubara, H.; Shimbara, Y.; Nagashima, M.; Sakuda, M.; Mori, T.; 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.

  15. Isospin properties of electric dipole excitations in 48Ca

    NASA Astrophysics Data System (ADS)

    Derya, V.; Savran, D.; Endres, J.; Harakeh, M. N.; Hergert, H.; Kelley, J. H.; Papakonstantinou, P.; Pietralla, N.; Ponomarev, V. Yu.; Roth, R.; Rusev, G.; Tonchev, A. P.; Tornow, W.; Wörtche, H. J.; Zilges, A.

    2014-03-01

    Two different experimental approaches were combined to study the electric dipole strength in the doubly-magic nucleus 48Ca below the neutron threshold. Real-photon scattering experiments using bremsstrahlung up to 9.9 MeV and nearly mono-energetic linearly polarized photons with energies between 6.6 and 9.51 MeV provided strength distribution and parities, and an (α,α‧γ) experiment at Eα=136 MeV gave cross sections for an isoscalar probe. The unexpected difference observed in the dipole response is compared to calculations using the first-order random-phase approximation and points to an energy-dependent isospin character. A strong isoscalar state at 7.6 MeV was identified for the first time supporting a recent theoretical prediction.

  16. E2 giant resonances and an M1 component in the photofission of /sup 236/U

    SciTech Connect

    Arruda-Neto, J.D.T.; Herdade, S.B.; Berman, B.L.; Nascimento, I.C.

    1980-11-01

    Electrofission and photofission yields and electrofission-fragment angular distributions for /sup 236/U have been measured with fission-track detectors for incident electron energies from 5.5 to 33.0 MeV. Analysis of these data with the use of virtual-photon spectra calculated in distorted-wave Born approximation, combined with the known photofission cross section, results in the simultaneous determination for this nucleus of (a) a giant isoscalar E2 resonance located at 10.8 +- 0.4 MeV, having a width of 6 +- 1 MeV, and exhausting approx.70% of the isoscalar energy-weighted sum rule, and (b) a small M1 component located at 5.8 +- 0.2 MeV whose strength is <2% of that of the giant isoscalar E2 resonance. No evidence is seen for a giant isovector E2 resonance between 22 and 30 MeV.

  17. On the nature of the Dipole Pygmy Resonance

    SciTech Connect

    Lanza, E. G.; Vitturi, A.; Andres, M. V.; Catara, F.; Gambacurta, D.

    2011-10-28

    The nature of the low-lying dipole states in neutron-rich nuclei, often associated to the Pygmy Dipole Resonance, has been investigated. This has been done by describing them within the Hartree-Fock plus RPA formalism. The analysis shows that they are not of collective nature although many particle-hole configurations participate to their formation. Taking advantage of their strong isospin mixing one can envisage combined reaction processes involving the Coulomb and different mixtures of isoscalar and isovector nuclear interactions in order to provide more hints to unveil the characteristic features of these states.

  18. Toward the excited isoscalar meson spectrum from lattice QCD

    SciTech Connect

    Dudek, Jozef J.; Edwards, Robert G.; Guo, Peng; Thomas, Christopher E.

    2013-11-18

    We report on the extraction of an excited spectrum of isoscalar mesons using lattice QCD. Calculations on several lattice volumes are performed with a range of light quark masses corresponding to pion masses down to about ~400 MeV. The distillation method enables us to evaluate the required disconnected contributions with high statistical precision for a large number of meson interpolating fields. We find relatively little mixing between light and strange in most JPC channels; one notable exception is the pseudoscalar sector where the approximate SU(3)F octet, singlet structure of the η, η' is reproduced. We extract exotic JPC states, identified as hybrid mesons in which an excited gluonic field is coupled to a color-octet qqbar pair, along with non-exotic hybrid mesons embedded in a qq¯-like spectrum.

  19. Toward the excited isoscalar meson spectrum from lattice QCD

    DOE PAGESBeta

    Dudek, Jozef J.; Edwards, Robert G.; Guo, Peng; Thomas, Christopher E.

    2013-11-18

    We report on the extraction of an excited spectrum of isoscalar mesons using lattice QCD. Calculations on several lattice volumes are performed with a range of light quark masses corresponding to pion masses down to about ~400 MeV. The distillation method enables us to evaluate the required disconnected contributions with high statistical precision for a large number of meson interpolating fields. We find relatively little mixing between light and strange in most JPC channels; one notable exception is the pseudoscalar sector where the approximate SU(3)F octet, singlet structure of the η, η' is reproduced. We extract exotic JPC states, identifiedmore » as hybrid mesons in which an excited gluonic field is coupled to a color-octet qqbar pair, along with non-exotic hybrid mesons embedded in a qq¯-like spectrum.« less

  20. Photoresponse of 60Ni below 10-MeV excitation energy: Evolution of dipole resonances in fp-shell nuclei near N=Z

    NASA Astrophysics Data System (ADS)

    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.

  1. How different is the time-averaged field from that of a geocentric axial dipole ? Making the best of paleomagnetic directional data using the statistical Giant Gaussian Process approach.

    NASA Astrophysics Data System (ADS)

    Hulot, G.; Khokhlov, A.; Johnson, C. L.

    2012-12-01

    It is well known that the geometry of the recent time-averaged paleomagnetic field (TAF) is very close to that of a geocentric axial dipole (GAD). Yet, numerous numerical dynamo simulations show that some departures from such a simple geometry is to be expected, not least because of the heterogeneous thermal core-mantle boundary conditions that the convecting mantle imposes on the geodynamo. Indeed, many TAF models recovered from averaging lava flow paleomagnetic directional data (the most numerous and reliable of all data) would suggest this is the case. However, assessing the significance of such minor departures from the GAD is particularly challenging, because non-linear directional data are sensitive not only to the time-averaged component of the field, but also to its time fluctuating component, known as the paleosecular variation (PSV). This means that in addition to data errors, PSV also must be taken into account when assessing any lava flow directional data based claims of departures of the TAF from the GAD. Furthermore, because of limited age information for these data , it is necessary to assess departures from the GAD by resorting to a statistical approach. We report recent progress using an approach we have suggested and further developed (Khokhlov et al., Geophysical Journal International, 2001, 2006) to test the compatibility of combined time-averaged (TAF) and paleosecular variation (PSV) field models, against any lava flow paleomagnetic database, asssuming that these TAF and PSV models are defined within the Giant Gaussian Process statistical framework. In particular we will show how sensitive statistical measures of the compatibility of a combined set of TAF and PSV models with a given directional database can be defined. These measures can be used to test published TAF and PSV models with updated 0-5 Ma lava flow paleomagnetic data sets. They also lay the groundwork for designing inverse methods better suited to seek the minimum required

  2. Fission decay of the isoscalar giant quadrupole resonance in 24Mg

    NASA Astrophysics Data System (ADS)

    Lawitzki, S.; Pade, D.; Gonsior, B.; Uhlhorn, C. D.; Brandenburg, S.; Harakeh, M. N.; Wilschut, H. W.

    1986-07-01

    The 24Mg(α, α‧) 12C+ 12C reaction was studied by measuring 12C fragments in coincidence with inelastically scattered α-particles at Eα = 120 MeV. Both 12C fragments were identified using the ΔE - E technique. The measured angular correlations indicate that the 12C gs+ 12C gs decay channel is dominated by decay of L = 2 strength, which yields an integrated fraction of 0.14% of the E2 EWSR strength in comparison with 22.2% of the E2 EWSR strength observed in singles inelastic α-scattering experiments in the same excitation energy region.

  3. Dynamic dipoles

    NASA Astrophysics Data System (ADS)

    Griffiths, David J.

    2011-08-01

    We study stationary but time-dependent ideal (point) electric and magnetic dipoles, both the conventional type consisting of electric charges and currents and the hypothetical kind composed of magnetic monopoles and their currents. We derive their potentials and fields, and calculate the energy, momentum, and angular momentum they radiate.

  4. Pygmy dipole mode in deformed neutron-rich Mg isotopes close to the drip line

    SciTech Connect

    Yoshida, Kenichi

    2009-10-15

    We investigate the microscopic structure of the low-lying isovector-dipole excitation mode in neutron-rich {sup 36,38,40}Mg close to the drip line by means of the deformed quasiparticle random-phase approximation employing the Skyrme and the local pairing energy-density functionals. It is found that the low-lying bump structure above the neutron emission-threshold energy develops when the drip line is approached, and that the isovector dipole strength at E{sub x}<10 MeV exhausts about 6.0% of the classical Thomas-Reiche-Kuhn dipole sum rule in {sup 40}Mg. We obtained the collective dipole modes at around 8-10 MeV in Mg isotopes, that consist of many two-quasiparticle excitations of the neutron. The transition density clearly shows an oscillation of the neutron skin against the isoscalar core. We found significant coupling effects between the dipole and octupole excitation modes due to the nuclear deformation. It is also found that the responses for the compressional dipole and isoscalar octupole excitations are much enhanced in the lower energy region.

  5. Collisional width of giant resonances and interplay with Landau damping

    SciTech Connect

    Bonasera, A.; Burgio, G. F.; Di Toro, M.; Wolter, H. H.

    1989-06-01

    We present a semiclassical method to calculate the widths of giant resonances. We solve a mean-field kinetic equation (Vlasov equation) with collision terms treated within the relaxation time approximation to construct a damped strength distribution for collective motions. The relaxation time is evaluated from the time evolution of distortions in the nucleon momentum distribution using a test-particle approach. The importance of an energy dependent nucleon-nucleon cross section is stressed. Results are shown for isoscalar giant quadrupole and octupole motions. A quite important interplay between self-consistent (Landau) and collisional damping is revealed.

  6. Isoscalar-isovector proton-neutron pairing and quartet condensation in N =Z nuclei

    NASA Astrophysics Data System (ADS)

    Sambataro, M.; Sandulescu, N.

    2016-05-01

    We show that the correlations generated in the ground state of N =Z nuclei by the isovector and isoscalar pairing forces can be treated with high precision as a condensate of alpha-like quartets. To treat these correlations, the quartet condensation model (QCM) is extended to the treatment of spherically symmetric isovector (T =1 ,J =0 ) and isoscalar (T =0 ,J =1 ) pairing forces. Within the QCM, we discuss the competition between T =1 and T =0 pairing correlations in the case of a two-level model and for N =Z nuclei with nucleons moving in the open shells above 16O,40Ca, and 100Sn. We show that, in N =Z systems, isovector and isoscalar proton-neutron pairing correlations always coexist.

  7. Low-Energy Dipole Modes of Excitation Below the Neutron Separation Energy

    SciTech Connect

    Tonchev, A. P.; Howell, C. R.; Tornow, W.; Angell, C.; Boswell, M.; Karwowski, H. J.; Kelley, J. H.; Tsoneva, N.

    2006-03-13

    The nuclear resonance fluorescence experiments have been performed at the High Intensity Gamma Source (HI{gamma}S) on 138Ba nuclei using four 60% efficient HPGe detectors. Excitation energies, spin, parities, and decay branching ratios were measured for the low-energy dipole modes of excitations. Experimental results on the parity measurement below the neutron separation energy shows that all dipole states in this energy region exhibit E1 excitation. These results are consistent with theoretical prediction of the collective isoscalar nature of this low-energy mode of excitation.

  8. Phase-space exploration in nuclear giant resonance decay

    SciTech Connect

    Drozdz, S.; Nishizaki, S.; Wambach, J.; Speth, J. Institute of Nuclear Physics, PL-31-342 Krakow Department of Physics, University of Illinois at Urbana, Illinois 61801 College of Humanities and Social Sciences, Iwate University, Ueda 3-18-34, Morioka 020 )

    1995-02-13

    The rate of phase-space exploration in the decay of isovector and isoscalar giant quadrupole resonances in [sup 40]Ca is analyzed. The study is based on the time dependence of the survival probability and of the spectrum of generalized entropies evaluated in the space of one-particle--one-hole (1p-1h) and 2p-2h states. Three different cases for the level distribution of 2p-2h background states, corresponding to (a) high degeneracy, (b) classically regular motion, and (c) classically chaotic motion, are studied. In the latter case the isovector excitation evolves almost statistically while the isoscalar excitation remains largely localized, even though it penetrates the whole available phase space.

  9. New Insight into the Pygmy Dipole Resonance in Stable Nuclei

    SciTech Connect

    Neumann-Cosel, P. von

    2008-11-11

    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 ({gamma},{gamma}') experiments. These help to distinguish between microscopic QRPA calculations based on either a relativistic or a nonrelativistic mean-field description, predicting significantly different properties of the PDR. The second part presents attempts to unravel the structure of dipoles modes at energies below the giant dipole resonance (GDR) in {sup 208}Pb with a high-resolution measurement of the (p-vector,p-vector') reaction under 0 deg.

  10. Determination of the pairing-strength constants in the isovector plus isoscalar pairing case

    NASA Astrophysics Data System (ADS)

    Mokhtari, D.; Fellah, M.; Allal, N. H.

    2016-05-01

    A method for the determination of the pairing-strength constants, in the neutron-proton (n-p) isovector plus isoscalar pairing case, is proposed in the framework of the BCS theory. It is based on the fitting of these constants to reproduce the experimentally known pairing gap parameters as well as the root-mean-squared (r.m.s) charge radii values. The method is applied to some proton-rich even-even nuclei. The single-particle energies used are those of a deformed Woods-Saxon mean field. It is shown that the obtained value of the ratio GnpT=0/G npT=1 is of the same order as the ones, arbitrary chosen, of some previous works. The effect of the inclusion of the isoscalar n-p pairing in the r.m.s matter radii is then numerically studied for the same nuclei.

  11. Nonquenched Isoscalar Spin-M1 Excitations in sd-Shell Nuclei.

    PubMed

    Matsubara, H; Tamii, A; Nakada, H; Adachi, T; Carter, J; Dozono, M; Fujita, H; Fujita, K; Fujita, Y; Hatanaka, K; Horiuchi, W; Itoh, M; Kawabata, T; Kuroita, S; Maeda, Y; Navrátil, P; von Neumann-Cosel, P; Neveling, R; Okamura, H; Popescu, L; Poltoratska, I; Richter, A; Rubio, B; Sakaguchi, H; Sakaguchi, S; Sakemi, Y; Sasamoto, Y; Shimbara, Y; Shimizu, Y; Smit, F D; Suda, K; Tameshige, Y; Tokieda, H; Yamada, Y; Yosoi, M; Zenihiro, J

    2015-09-01

    Differential cross sections of isoscalar and isovector spin-M1 (0(+)→1(+)) transitions are measured using high-energy-resolution proton inelastic scattering at E(p)=295  MeV on (24)Mg, (28)Si, (32)S, and (36)Ar at 0°-14°. The squared spin-M1 nuclear transition matrix elements are deduced from the measured differential cross sections by applying empirically determined unit cross sections based on the assumption of isospin symmetry. The ratios of the squared nuclear matrix elements accumulated up to E(x)=16  MeV compared to a shell-model prediction are 1.01(9) for isoscalar and 0.61(6) for isovector spin-M1 transitions, respectively. Thus, no quenching is observed for isoscalar spin-M1 transitions, while the matrix elements for isovector spin-M1 transitions are quenched by an amount comparable with the analogous Gamow-Teller transitions on those target nuclei. PMID:26382672

  12. Pygmy Dipole Strength and Neutron Skins in Exotic Nuclei

    NASA Astrophysics Data System (ADS)

    Klimkiewicz, A.; Paar, N.; Adrich, P.; Fallot, M.; Boretzky, K.; Aumann, T.; Cortina-Gil, D.; Pramanik, U. Datta; Elze, Th. W.; Emling, H.; Geissel, H.; Hellström, M.; Jones, K. L.; Kratz, J. V.; Kulessa, R.; Nociforo, C.; Palit, R.; Simon, H.; Surówka, G.; Sümmerer, K.; Vretenar, D.; Waluś, W.

    2008-05-01

    Dipole strength distributions were determined for the neutron-rich nuclei 129-132Sn and 133,134Sb from electromagnetic excitation in an experiment using the FRS-LAND setup. For all nuclei, a sizeable fraction of ``pygmy'' dipole strength at excitation energies well below the giant dipole resonance was observed. The integrated low-lying dipole strength of the nuclei with low neutron separation energies can be compared to results for stable nuclei (e.g. N = 82 isotopes) determined for the energy regime of 5-9 MeV. A clear increase of the dipole strength with increasing asymmetry of the nuclei is observed. Comparing the ratio of the low-lying dipole over the giant dipole strength to recent relativistic mean field calculations, values for the parameters a4 and p0 of the symmetry energy and for the neutron skin thickness are derived. Averaged over 130Sn and 132Sn we extract a4 = 31.8+/-1.3 MeV and p0 = 2.2+/-0.5 MeV/fm3. The neutron skin sizes are determined to Rn-Rp = 0.23+/-0.03 fm and 0.24+/-0.03 fm for 130Sn and 132Sn, respectively. For 208Pb a neutron skin thickness of Rn-Rp = 0.18+/-0.035 fm follows, when applying the same method and using earlier published experimental findings on the dipole strength.

  13. Solvents level dipole moments.

    PubMed

    Liang, Wenkel; Li, Xiaosong; Dalton, Larry R; Robinson, Bruce H; Eichinger, Bruce E

    2011-11-01

    The dipole moments of highly polar molecules measured in solution are usually smaller than the molecular dipole moments that are calculated with reaction field methods, whereas vacuum values are routinely calculated in good agreement with available vapor phase data. Whether from Onsager's theory (or variations thereof) or from quantum mechanical methods, the calculated molecular dipoles in solution are found to be larger than those measured. The reason, of course, is that experiments measure the net dipole moment of solute together with the polarized (perturbed) solvent "cloud" surrounding it. Here we show that the reaction field charges that are generated in the quantum mechanical self-consistent reaction field (SCRF) method give a good estimate of the net dipole moment of the solute molecule together with the moment arising from the reaction field charges. This net dipole is a better description of experimental data than the vacuum dipole moment and certainly better than the bare dipole moment of the polarized solute molecule. PMID:21923185

  14. Wideband microstrip dipole

    NASA Astrophysics Data System (ADS)

    Dey, Supriyo; Aanandan, C. K.; Jose, K. A.; Mohanan, P.; Nair, K. G.

    1992-12-01

    A new wideband half-wave microstrip dipole antenna is described which operates in low-frequency range with more than 5 percent 2:1 VSWR bandwidth. The design is based on a stripline feeding mechanism to prevent radiation from the feeding structure and on proper end-loading of dipole arms to enhance the impedance bandwidth. It is concluded that this dipole can replace the conventional dipoles or existing microstrip antennas in phased array application.

  15. Ice Giant Exploration

    NASA Astrophysics Data System (ADS)

    Rymer, A. M.; Arridge, C. S.; Masters, A.; Turtle, E. P.; Simon, A. A.; Hofstadter, M. D.; Turrini, D.; Politi, R.

    2015-12-01

    The Ice Giants in our solar system, Uranus and Neptune, are fundamentally different from their Gas Giant siblings Jupiter and Saturn, from the different proportions of rock and ice to the configuration of their planetary magnetic fields. Kepler space telescope discoveries of exo-planets indicate that planets of this type are among the most ubiquitous universally and therefore a future mission to explore the nature of the Ice Giants in our own solar system will provide insights into the nature of extra-solar system objects in general. Uranus has the smallest self- luminosity of all the planets, potentially related to catastrophic events early in the planet's history, which also may explain Uranus' large obliquity. Uranus' atmosphere is subject to extreme seasonal forcing making it unique in the Solar System. Neptune is also unique in a number of ways, notably its large moon Triton which is likely a captured Kuiper Belt Object and one of only two moons in the solar system with a robustly collisional atmosphere. Similar to Uranus, the angle between the solar wind and the magnetic dipole axis is subject to large-amplitude variations on both diurnal and seasonal timescales, but peculiarly it has one of the quietest magnetospheres of the solar system, at least according to Voyager 2, the only spacecraft to encounter Neptune to date. A comprehensive mission, as advocated in the Decadal Survey, would provide enormous science return but is also challenging and expensive. In this presentation we will discuss mission scenarios and suggest how collaboration between disciplines and internationally can help us to pursue a mission that includes Ice Giant exploration.

  16. Are there nuclear structure effects on the isoscalar giant monopole resonance and nuclear incompressibility near A ∼ 90?

    NASA Astrophysics Data System (ADS)

    Gupta, Y. K.; Garg, U.; Howard, K. B.; Matta, J. T.; Şenyiğit, M.; Itoh, M.; Ando, S.; Aoki, T.; Uchiyama, A.; Adachi, S.; Fujiwara, M.; Iwamoto, C.; Tamii, A.; Akimune, H.; Kadono, C.; Matsuda, Y.; Nakahara, T.; Furuno, T.; Kawabata, T.; Tsumura, M.; Harakeh, M. N.; Kalantar-Nayestanaki, N.

    2016-09-01

    "Background-free" spectra of inelastic α-particle scattering have been measured at a beam energy of 385 MeV in 90,92Zr and 92Mo at extremely forward angles, including 0°. The ISGMR strength distributions for the three nuclei coincide with each other, establishing clearly that nuclear incompressibility is not influenced by nuclear shell structure near A ∼ 90 as was claimed in recent measurements.

  17. Isoscalar monopole resonance of the alpha particle: a prism to nuclear Hamiltonians.

    PubMed

    Bacca, Sonia; Barnea, Nir; Leidemann, Winfried; Orlandini, Giuseppina

    2013-01-25

    We present an ab initio study of the isoscalar monopole excitations of (4)He using different realistic nuclear interactions, including modern effective field theory potentials. In particular we concentrate on the transition form factor F(M) to the narrow 0(+) resonance close to threshold. F(M) exhibits a strong potential model dependence, and can serve as a kind of prism to distinguish among different nuclear force models. Compared to the measurements obtained from inelastic electron scattering off ^{4}He, one finds that the state-of-the-art theoretical transition form factors are at variance with experimental data, especially in the case of effective field theory potentials. We discuss some possible reasons for such a discrepancy, which still remains a puzzle. PMID:25166158

  18. Changes in earth's dipole.

    PubMed

    Olson, Peter; Amit, Hagay

    2006-11-01

    The dipole moment of Earth's magnetic field has decreased by nearly 9% over the past 150 years and by about 30% over the past 2,000 years according to archeomagnetic measurements. Here, we explore the causes and the implications of this rapid change. Maps of the geomagnetic field on the core-mantle boundary derived from ground-based and satellite measurements reveal that most of the present episode of dipole moment decrease originates in the southern hemisphere. Weakening and equatorward advection of normal polarity magnetic field by the core flow, combined with proliferation and growth of regions where the magnetic polarity is reversed, are reducing the dipole moment on the core-mantle boundary. Growth of these reversed flux regions has occurred over the past century or longer and is associated with the expansion of the South Atlantic Anomaly, a low-intensity region in the geomagnetic field that presents a radiation hazard at satellite altitudes. We address the speculation that the present episode of dipole moment decrease is a precursor to the next geomagnetic polarity reversal. The paleomagnetic record contains a broad spectrum of dipole moment fluctuations with polarity reversals typically occurring during dipole moment lows. However, the dipole moment is stronger today than its long time average, indicating that polarity reversal is not likely unless the current episode of moment decrease continues for a thousand years or more. PMID:16915369

  19. Tevatron AC dipole system

    SciTech Connect

    Miyamoto, R.; Kopp, S.E.; 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.

  20. Microstrip monpulse dipole array

    NASA Astrophysics Data System (ADS)

    Miccioli, W.; Toth, J.; Sa, N.; Lewis, M.

    1985-01-01

    The development of a microstrip radiating aperture utilizing multiple microstrip dipole radiators fed by a resonant feed configuration is described. This array combines an efficient capacitively coupled radiator feeding mechanism with a planar power divider configuration to achieve an extremely thin, lightweight antenna aperture. Linear array dipole matching theory and radiator bandwidth improvement techniques are also described. A quadrant based microstrip monopulse antenna was constructed. Experimental data from this array, its subassemblies and individual components are presented and compared to analytical predictions.

  1. Chaos-driven decay of nuclear giant resonances: Quantum route to self-organization

    SciTech Connect

    Drozdz, S.; Nishizaki, S.; Wambach, J. Institute of Nuclear Physics, PL-31-342 Krakow Institut fuer Kernphysik, Forschungszentrum Juelich, D-5170 Juelich College of Humanities and Social Sciences, Iwate University, Ueda 3-18-34, Morioka 020 )

    1994-05-02

    The influence of background states with increasing level of complexity on the strength distribution of the isoscalar and isovector giant quadrupole resonance in [sup 40]Ca is studied. It is found that the background characteristics, typical for chaotic systems, strongly affect the fluctuation properties of the strength distribution. In particular, the small components of the wave function obey a scaling law analogous to self-organized systems at the critical state. This appears to be consistent with the Porter-Thomas distribution of the transition strength.

  2. Excitation of giant monopole resonance in {sup 24}Mg using {sup 6}Li scattering

    SciTech Connect

    Dennert, H.; Aschenauer, E.; Eyrich, W.; Lehmann, A.; Moosburger, M.; Scholz, N.; Wirth, H.; Gils, H.J.; Rebel, H.; Zagromski, S.

    1995-12-01

    The isoscalar giant monopole resonance in the nucleus {sup 24}Mg was investigated by inelastic {sup 6}Li scattering at {ital E}{sub Li}=156 MeV. At extreme forward angles fragmented {ital E}0 strength was observed up to {ital E}{sub {ital x}}=23 MeV. The extracted strength centered at 18.3{plus_minus}0.5 MeV excitation energy with a width of {Gamma}=4.8{plus_minus}0.5 MeV corresponds to 97.3%{plus_minus}15% of the {ital E}0 energy weighted sum rule.

  3. Soft dipole resonance and halo structure of 11Li

    NASA Astrophysics Data System (ADS)

    Kanungo, Rituparna

    2016-03-01

    The discovery of the nuclear halo in rare isotopes has ushered a new era in nuclear science breaking the boundaries of conventional concepts. The halo properties elucidate new features that till date remain a challenge to decipher from fundamental principles. Our knowledge on the halo is still gradually unfolding and reaching new levels of precision as efforts continue towards new experimental developments. In recent times, low-energy reactions in inverse kinematics have become possible providing a wealth of new structure information. In this presentation we will introduce a new reaction spectroscopy facility, IRIS, with a novel thin windowless solid H2/D2 target for studying transfer and inelastic scattering reactions of rare isotopes with very low yields. It was postulated that the loosely bound halo of two neutrons may lead to a core-halo oscillation resulting in dipole resonance(s) at very low excitation energy, called soft dipole resonance. Despite decades of search for this new phenomenon using various techniques, such as, no firm conclusion was reached. The presentation will discuss new results from IRIS that shows evidence of a soft dipole resonance state and further unveils its isoscalar character. New results of neutron transfer from 11Li will be presented showing resonance state(s) in the neutron unbound 10Li subsystem hence facilitating a description of the wavefunction of 11Li. NSERC, Canada Foundation for Innovation, Nova Scotia Research and Innovation Trust, grant-in-aid program of the Japanese government under Contract No. 23224008, US DOE Contract No. DE-AC52-07NA27344.

  4. Symmetry of Isoscalar Matrix Elements and Systematics in the sd and beginning of fp shells

    NASA Astrophysics Data System (ADS)

    Orce, J. N.; Petkov, P.; Velázquez, V.; McKay, C. J.; Lesher, S. R.; Choudry, S.; Mynk, M.; Linnemann, A.; Jolie, J.; von Brentano, P.; Werner, V.; Yates, S. W.; McEllistrem, M. T.

    2006-03-01

    A careful determination of the lifetime and measurement of the branching ratio for decay of the first 2T=1+ state in 42Sc has allowed an accurate experimental test of charge independence in the A = 42 isobaric triplet. A lifetime of 69(17) fs was measured at the University of Kentucky, while relative intensities for the 975 keV and 1586 keV transitions depopulating the first 2T=1+ state have been determined at the University of Cologne as 100(1) and 8(1), respectively. Both measurements give an isoscalar matrix element, M0, of 6.4(9) (W.u.)1/2. This result confirms charge independence for the A=42 isobaric triplet. Shell model calculations have been carried out for understanding the global trend of M0 values for A = 4n + 2 isobaric triplets ranging from A = 18 to A = 42. The 21 (T=1)+ → 01 (T=1)+ transition energies, reduced transition probabilities and M0 values are reproduced to a high degree of accuracy. The trend of M0 strength along the sd shell is interpreted in terms of the shell structure. Certain discrepancies arise at the extremes of the sd shell, for the A = 18 and A = 38 isobaric triplets, which might be explained in terms of the low valence space at the extremes of the sd shell.

  5. Symmetry of Isoscalar Matrix Elements and Systematics in the sd and beginning of fp shells

    SciTech Connect

    Orce, J. N.; McKay, C. J.; Lesher, S. R.; Choudry, S.; Mynk, M.; McEllistrem, M. T.; Petkov, P.; Velazquez, V.; Linnemann, A.; Jolie, J.; Brentano, P. von; Werner, V.; Yates, S. W.

    2006-03-13

    A careful determination of the lifetime and measurement of the branching ratio for decay of the first 2{sub T=1}{sup +} state in 42Sc has allowed an accurate experimental test of charge independence in the A = 42 isobaric triplet. A lifetime of 69(17) fs was measured at the University of Kentucky, while relative intensities for the 975 keV and 1586 keV transitions depopulating the first 2{sub T=1}{sup +} state have been determined at the University of Cologne as 100(1) and 8(1), respectively. Both measurements give an isoscalar matrix element, M0, of 6.4(9) (W.u.)1/2. This result confirms charge independence for the A=42 isobaric triplet. Shell model calculations have been carried out for understanding the global trend of M0 values for A = 4n + 2 isobaric triplets ranging from A = 18 to A = 42. The 2{sub 1(T=1)}{sup +} {yields} 0{sub 1(T=1)}{sup +} transition energies, reduced transition probabilities and M0 values are reproduced to a high degree of accuracy. The trend of M0 strength along the sd shell is interpreted in terms of the shell structure. Certain discrepancies arise at the extremes of the sd shell, for the A = 18 and A 38 isobaric triplets, which might be explained in terms of the low valence space at the extremes of the sd shell.

  6. Dipole Well Location

    Energy Science and Technology Software Center (ESTSC)

    1998-08-03

    The problem here is to model the three-dimensional response of an electromagnetic logging tool to a practical situation which is often encountered in oil and gas exploration. The DWELL code provide the electromagnetic fields on the axis of a borehole due to either an electric or a magnetic dipole located on the same axis. The borehole is cylindrical, and is located within a stratified formation in which the bedding planes are not horizontal. The anglemore » between the normal to the bedding planes and the axis of the borehole may assume any value, or in other words, the borehole axis may be tilted with respect to the bedding planes. Additionally, all of the formation layers may have invasive zones of drilling mud. The operating frequency of the source dipole(s) extends from a few Hertz to hundreds of Megahertz.« less

  7. Dipole Well Location

    SciTech Connect

    Newman, Gregory

    1998-08-03

    The problem here is to model the three-dimensional response of an electromagnetic logging tool to a practical situation which is often encountered in oil and gas exploration. The DWELL code provide the electromagnetic fields on the axis of a borehole due to either an electric or a magnetic dipole located on the same axis. The borehole is cylindrical, and is located within a stratified formation in which the bedding planes are not horizontal. The angle between the normal to the bedding planes and the axis of the borehole may assume any value, or in other words, the borehole axis may be tilted with respect to the bedding planes. Additionally, all of the formation layers may have invasive zones of drilling mud. The operating frequency of the source dipole(s) extends from a few Hertz to hundreds of Megahertz.

  8. Isospin Character of Low-Lying Pygmy Dipole States in Pb208 via Inelastic Scattering of O17 Ions

    NASA Astrophysics Data System (ADS)

    Crespi, F. C. L.; Bracco, A.; Nicolini, R.; Mengoni, D.; Pellegri, L.; Lanza, E. G.; Leoni, S.; Maj, A.; Kmiecik, M.; Avigo, R.; Benzoni, G.; Blasi, N.; Boiano, C.; Bottoni, S.; Brambilla, S.; Camera, F.; Ceruti, S.; Giaz, A.; Million, B.; Morales, A. I.; Vandone, V.; Wieland, O.; Bednarczyk, P.; Ciemała, M.; Grebosz, J.; Krzysiek, M.; Mazurek, K.; Zieblinski, M.; Bazzacco, D.; Bellato, M.; Birkenbach, B.; Bortolato, D.; Calore, E.; Cederwall, B.; Charles, L.; de Angelis, G.; Désesquelles, P.; Eberth, J.; Farnea, E.; Gadea, A.; Görgen, A.; Gottardo, A.; Isocrate, R.; Jolie, J.; Jungclaus, A.; Karkour, N.; Korten, W.; Menegazzo, R.; Michelagnoli, C.; Molini, P.; Napoli, D. R.; Pullia, A.; Recchia, F.; Reiter, P.; Rosso, D.; Sahin, E.; Salsac, M. D.; Siebeck, B.; Siem, S.; Simpson, J.; Söderström, P.-A.; Stezowski, O.; Theisen, Ch.; Ur, C.; Valiente-Dobón, J. J.

    2014-07-01

    The properties of pygmy dipole states in Pb208 were investigated using the Pb208(O17, O17'γ) reaction at 340 MeV and measuring the γ decay with high resolution with the AGATA demonstrator array. Cross sections and angular distributions of the emitted γ rays and of the scattered particles were measured. The results are compared with (γ, γ') and (p, p') data. The data analysis with the distorted wave Born approximation approach gives a good description of the elastic scattering and of the inelastic excitation of the 2+ and 3- states. For the dipole transitions a form factor obtained by folding a microscopically calculated transition density was used for the first time. This has allowed us to extract the isoscalar component of the 1- excited states from 4 to 8 MeV.

  9. Average Description of Dipole Gamma Transitions in Hot Atomic Nuclei

    NASA Astrophysics Data System (ADS)

    Plujko, V. A.; Gorbachenko, O. M.; Rovenskykh, E. P.; Zheltonozhskii, V. A.

    2014-04-01

    A new version of the modified Lorentzian approach for radiative strength function is proposed. It is based on renewed systematics for giant dipole resonance (GDR) parameters. The gamma-decay strength functions are calculated using new GDR parameters and compared with experimental data. It is demonstrated that closed-form approaches with energy-dependent width of the gamma strength, as a rule, provide a reliable simple method for description of gamma-decay processes.

  10. Giant Axonal Neuropathy

    MedlinePlus

    ... Diversity Find People About NINDS NINDS Giant Axonal Neuropathy Information Page Table of Contents (click to jump ... done? Clinical Trials Organizations What is Giant Axonal Neuropathy? Giant axonal neuropathy (GAN) is a rare inherited ...

  11. DVCS via color dipoles

    SciTech Connect

    Kopeliovich, B.; Schmidt, I.; Siddikov, M.

    2009-03-23

    We study the DVCS amplitude within the color dipole approach employing a nonperturbative wave function for the real photon. We found that the model is able to decribe the absolute value of the cross section and the t-slope, but predicts too steep Q{sup 2}-dependence in comparison with H1 data.

  12. Experiments with Dipole Antennas

    ERIC Educational Resources Information Center

    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…

  13. The pygmy dipole resonance in neutron-rich nuclei

    NASA Astrophysics Data System (ADS)

    Quang Hung, Nguyen; Kiet, Hoang Anh Tuan; Duc, Huynh Ngoc; Thi Chuong, Nguyen

    2016-06-01

    The pygmy dipole resonance (PDR), which has been observed via the enhancement of the electric dipole strength E1 of atomic nuclei, is studied within a microscopic collective model. The latter employs the Hartree-Fock (HF) method with effective nucleon-nucleon interactions of the Skyrme types plus the random-phase approximation (RPA). The results of the calculations obtained for various even-even nuclei such as 16-28O, 40-58Ca, 100-120Sn, and 182-218Pb show that the PDR is significantly enhanced when the number of neutrons outside the stable core of the nucleus is increased, that is, in the neutron-rich nuclei. As the result, the relative ratio between the energy weighted sum of the strength of the PDR and that of the GDR (giant dipole resonance) does not exceed 4%. The collectivity of the PDR and GDR states will be also discussed.

  14. Geometrical Simplification of the Dipole-Dipole Interaction Formula

    ERIC Educational Resources Information Center

    Kocbach, Ladislav; Lubbad, Suhail

    2010-01-01

    Many students meet dipole-dipole potential energy quite early on when they are taught electrostatics or magnetostatics and it is also a very popular formula, featured in encyclopedias. We show that by a simple rewriting of the formula it becomes apparent that, for example, by reorienting the two dipoles, their attraction can become exactly twice…

  15. Microstrip dipoles on cylindrical structures

    NASA Astrophysics Data System (ADS)

    Alexopoulos, N. G.; Uslenghi, P. L. E.; Uzunoglu, N. K.

    1981-12-01

    An electric dipole tangent to the outer surface of a dielectric layer which coats a metallic cylinder is considered. Exact expressions are obtained for the electromagnetic field produced by the dipole, both inside the coating layer and in the surrounding free space. Asymptotic results are derived for a cylinder whose diameter is large compared to the wavelength. Arrays of elementary dipoles are discussed.

  16. Giant Dipole Resonance decay of hot rotating 88Mo

    NASA Astrophysics Data System (ADS)

    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.

  17. Fission and dipole resonances in metal clusters

    SciTech Connect

    Martin, T. P.; Billas, I. M. L.; Branz, W.; Heinebrodt, M.; Tast, F.; Malinowski, N.

    1997-06-20

    It is not obvious that metal clusters should behave like atomic nuclei--but they do. Of course the energy and distance scales are quite different. But aside from this, the properties of these two forms of condensed matter are amazingly similar. The shell model developed by nuclear physicists describes very nicely the electronic properties of alkali metal clusters. The giant dipole resonances in the excitation spectra of nuclei have their analogue in the plasmon resonances of metal clusters. Finally, the droplet model describing the fission of unstable nuclei can be successively applied to the fragmentation of highly charged metal clusters. The similarity between clusters and nuclei is not accidental. Both systems consist of fermions moving, nearly freely, in a confined space.

  18. Electromagnetically coupled microstrip dipoles

    NASA Astrophysics Data System (ADS)

    Oltman, H. G.; Huebner, D. A.

    1981-01-01

    A new class of printed circuit radiator consisting of a microstrip dipole electromagnetically coupled to a microstrip feed line is described. Several configurations which differ in bandwidth, efficiency, and construction simplicity are presented. A geometry which has been found to be optimum for many applications is noted. Radiation characteristics of both isolated elements and arrays of elements are examined. Experimental and theoretical results are presented.

  19. Dipole defects in beryl

    NASA Astrophysics Data System (ADS)

    Holanda, B. A.; Cordeiro, R. C.; Blak, A. R.

    2010-11-01

    Dipole defects in gamma irradiated and thermally treated beryl (Be3Al2Si6O18) 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.

  20. Giant Magnons Meet Giant Gravitons

    SciTech Connect

    Hofman, Diego M.

    2008-07-28

    We study the worldsheet reflection matrix of a string attached to a D-brane in AdS{sub 5}xS{sup 5}. The D-brane corresponds to a maximal giant graviton that wraps an S{sup 3} inside S{sup 5}. In the gauge theory, the open string is described by a spin chain with boundaries. We focus on open strings with a large SO(6) charge and define an asymptotic boundary reflection matrix. Using the symmetries of the problem, we review the computation of the boundary reflection matrix, up to a phase. We also discuss weak and strong coupling computations where we obtain the overall phase factor and test our exact results.

  1. Lithium electric dipole polarizability

    SciTech Connect

    Puchalski, M.; KePdziera, D.; Pachucki, K.

    2011-11-15

    The electric dipole polarizability of the lithium atom in the ground state is calculated including relativistic and quantum electrodynamics corrections. The obtained result {alpha}{sub E}=164.0740(5) a.u. is in good agreement with the less accurate experimental value of 164.19(1.08) a.u. The small uncertainty of about 3 parts per 10{sup 6} comes from the approximate treatment of quantum electrodynamics corrections. Our theoretical result can be considered as a benchmark for more general atomic structure methods and may serve as a reference value for the relative measurement of polarizabilities of the other alkali-metal atoms.

  2. Superconducting dipole electromagnet

    DOEpatents

    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.

  3. Low-energy dipole excitations in neon isotopes and N=16 isotones within the quasiparticle random-phase approximation and the Gogny force

    SciTech Connect

    Martini, M.; Peru, S.; Dupuis, M.

    2011-03-15

    Low-energy dipole excitations in neon isotopes and N=16 isotones are calculated with a fully consistent axially-symmetric-deformed quasiparticle random phase approximation (QRPA) approach based on Hartree-Fock-Bogolyubov (HFB) states. The same Gogny D1S effective force has been used both in HFB and QRPA calculations. The microscopical structure of these low-lying resonances, as well as the behavior of proton and neutron transition densities, are investigated in order to determine the isoscalar or isovector nature of the excitations. It is found that the N=16 isotones {sup 24}O, {sup 26}Ne, {sup 28}Mg, and {sup 30}Si are characterized by a similar behavior. The occupation of the 2s{sub 1/2} neutron orbit turns out to be crucial, leading to nontrivial transition densities and to small but finite collectivity. Some low-lying dipole excitations of {sup 28}Ne and {sup 30}Ne, characterized by transitions involving the {nu}1d{sub 3/2} state, present a more collective behavior and isoscalar transition densities. A collective proton low-lying excitation is identified in the {sup 18}Ne nucleus.

  4. Giant Cell Arteritis

    MedlinePlus

    Giant cell arteritis is a disorder that causes inflammation of your arteries, usually in the scalp, neck, and arms. ... arteries, which keeps blood from flowing well. Giant cell arteritis often occurs with another disorder called polymyalgia ...

  5. Giant impacts on giant planets

    NASA Astrophysics Data System (ADS)

    de Pater, Imke

    2012-10-01

    The 2009 impact on Jupiter caught the world by surprise and cast doubt on impactor flux estimates for the outer solar system. Enhanced amateur planetary imaging techniques yield both high spatial resolution {enabling the 2009 impact debris field detection} and rapid frame rates {enabling the 2010 impact flash detections and lightcurve measurements}.We propose a Target of Opportunity program to image future impacts on Jupiter and Saturn. To remove the possibility of impact cloud non-detections, the program will be triggered only if an existing impact debris field is seen, an object on a collision course with Jupiter or Saturn is discovered, or an impact light curve is measured with an estimated total energy large enough to generate an impact cloud in a giant planet atmosphere.HST provides the only way to image these events in the ultraviolet, providing information on aerosol altitudes and on smaller particles that are less visible to ground-based infrared observations. High-resolution imaging with proper timing {not achievable from the ground} is required to measure precisely both the velocity fields of impact sites and the optical spectrum of impact debris. HST observations of past impacts on Jupiter have also served both as cornerstones of science investigations at other wavelengths and as vehicles for effective public outreach.Large outer solar system impacts are governed by the same physics as in the terrestrial events that dominate the impact threat to humans. Studying the behavior of impactors of various sizes and compositions, as they enter the atmosphere at varying angles and speeds, will better quantify terrestrial impact hazards.

  6. Giant impacts on giant planets

    NASA Astrophysics Data System (ADS)

    de Pater, Imke

    2014-10-01

    The 2009 impact and recent superbolides on Jupiter caught the world by surprise and cast doubt on impactor flux estimates for the outer solar system. Enhanced amateur planetary imaging techniques yield both high spatial resolution (enabling the 2009 impact debris field detection) and rapid frame rates (enabling the 2010/2012 impact flash detections and lightcurve measurements).We propose a ToO program to image future impacts on Jupiter and Saturn. To remove the possibility of impact cloud non-detections, the program will be triggered only if an existing impact debris field is seen, an object on a collision course with Jupiter or Saturn is discovered, or an impact light curve is measured with an estimated total energy large enough to generate an impact cloud in a giant planet atmosphere (10^20 J).HST provides the only way to image these events in the ultraviolet, providing information on aerosol altitudes and on smaller particles that are less visible to ground-based infrared observations. High-resolution imaging with proper timing (not achievable from the ground) is required to measure precisely both the velocity fields of impact sites and the optical spectrum of impact debris. HST observations of past impacts on Jupiter have also served both as cornerstones of science investigations at other wavelengths and as vehicles for effective public outreach.Large outer solar system impacts are governed by the same physics as in the terrestrial events that dominate the impact threat to humans. Studying the behavior of impactors of various sizes and compositions, as they enter the atmosphere at varying angles and speeds, will better quantify terrestrial impact hazards.

  7. Giant impacts on giant planets

    NASA Astrophysics Data System (ADS)

    de Pater, Imke

    2013-10-01

    The 2009 impact and recent superbolides on Jupiter caught the world by surprise and cast doubt on impactor flux estimates for the outer solar system. Enhanced amateur planetary imaging techniques yield both high spatial resolution {enabling the 2009 impact debris field detection} and rapid frame rates {enabling the 2010/2012 impact flash detections and lightcurve measurements}.We propose a ToO program to image future impacts on Jupiter and Saturn. To remove the possibility of impact cloud non-detections, the program will be triggered only if an existing impact debris field is seen, an object on a collision course with Jupiter or Saturn is discovered, or an impact light curve is measured with an estimated total energy large enough to generate an impact cloud in a giant planet atmosphere {10^20 J}.HST provides the only way to image these events in the ultraviolet, providing information on aerosol altitudes and on smaller particles that are less visible to ground-based infrared observations. High-resolution imaging with proper timing {not achievable from the ground} is required to measure precisely both the velocity fields of impact sites and the optical spectrum of impact debris. HST observations of past impacts on Jupiter have also served both as cornerstones of science investigations at other wavelengths and as vehicles for effective public outreach.Large outer solar system impacts are governed by the same physics as in the terrestrial events that dominate the impact threat to humans. Studying the behavior of impactors of various sizes and compositions, as they enter the atmosphere at varying angles and speeds, will better quantify terrestrial impact hazards.

  8. Ferrofluid Photonic Dipole Contours

    NASA Astrophysics Data System (ADS)

    Snyder, Michael; Frederick, Jonathan

    2008-03-01

    Understanding magnetic fields is important to facilitate magnetic applications in diverse fields in industry, commerce, and space exploration to name a few. Large electromagnets can move heavy loads of metal. Magnetic materials attached to credit cards allow for fast, accurate business transactions. And the Earth's magnetic field gives us the colorful auroras observed near the north and south poles. Magnetic fields are not visible, and therefore often hard to understand or characterize. This investigation describes and demonstrates a novel technique for the visualization of magnetic fields. Two ferrofluid Hele-Shaw cells have been constructed to facilitate the imaging of magnetic field lines [1,2,3,4]. We deduce that magnetically induced photonic band gap arrays similar to electrostatic liquid crystal operation are responsible for the photographed images and seek to mathematically prove the images are of exact dipole nature. We also note by comparison that our photographs are very similar to solar magnetic Heliosphere photographs.

  9. Effects of Dipole Potential Modifiers on Heterogenic Lipid Bilayers.

    PubMed

    Efimova, Svetlana S; Malev, Valery V; Ostroumova, Olga S

    2016-04-01

    In this work, we examine the ability of dipole modifiers, flavonoids, and RH dyes to affect the dipole potential (φ d) and phase separation in membranes composed of ternary mixtures of POPC with different sphingolipids and sterols. Changes in the steady-state conductance induced by cation-ionophore complexes have been measured to evaluate the changes in dipole potential of planar lipid bilayers. Confocal fluorescence microscopy has been employed to investigate lipid segregation in giant unilamellar vesicles. The effects of flavonoids on φ d depend on lipid composition and dipole modifier type. The effectiveness of RH dyes to increase φ d depends on sphingolipid type but is not influenced by sterol content. Tested modifiers lead to partial or complete disruption of gel domains in bilayers composed of POPC, sphingomyelin, and cholesterol. Substitution of cholesterol to ergosterol or 7-dehydrocholesterol leads to a loss of fluidizing effects of modifiers except phloretin. This may be due to various compositions of gel domains. The lack of influence of modifiers on phase scenario in vesicles composed of ternary mixtures of POPC, cholesterol, and phytosphingosine or sphinganine is related to an absence of gel-like phase. It was concluded that the membrane lateral heterogeneity affects the dipole-modifying abilities of the agents that influence the magnitude of φ d by intercalation into the bilayer and orientation of its own large dipole moments (phloretin and RH dyes). The efficacy of modifiers that do not penetrate deeply and affect φ d through water adsorption (phlorizin, quercetin, and myricetin) is not influenced by lateral heterogeneity of membrane. PMID:26454655

  10. Highly Automated Dipole EStimation (HADES).

    PubMed

    Campi, C; Pascarella, A; Sorrentino, A; Piana, M

    2011-01-01

    Automatic estimation of current dipoles from biomagnetic data is still a problematic task. This is due not only to the ill-posedness of the inverse problem but also to two intrinsic difficulties introduced by the dipolar model: the unknown number of sources and the nonlinear relationship between the source locations and the data. Recently, we have developed a new Bayesian approach, particle filtering, based on dynamical tracking of the dipole constellation. Contrary to many dipole-based methods, particle filtering does not assume stationarity of the source configuration: the number of dipoles and their positions are estimated and updated dynamically during the course of the MEG sequence. We have now developed a Matlab-based graphical user interface, which allows nonexpert users to do automatic dipole estimation from MEG data with particle filtering. In the present paper, we describe the main features of the software and show the analysis of both a synthetic data set and an experimental dataset. PMID:21437232

  11. Dipole oscillation modes in light α -clustering nuclei

    NASA Astrophysics Data System (ADS)

    He, W. B.; Ma, Y. G.; Cao, X. G.; Cai, X. Z.; Zhang, G. Q.

    2016-07-01

    The α cluster states are discussed in a model frame of extended quantum molecular dynamics. Different α cluster structures are studied in detail, such as 8Be two-α cluster structure, 12C triangle structure, 12 chain structure, 16O chain structure, 16O kite structure, and 16O square structure. The properties studied include the width of wave packets for different α clusters, momentum distribution, and the binding energy among α clusters. We also discuss how the α cluster degree of freedom affects nuclear collective vibrations. The cluster configurations in 12C and 16O are found to have corresponding characteristic spectra of giant dipole resonance (GDR), and the coherences of different α clusters' dipole oscillations are described in detail. The geometrical and dynamical symmetries of α -clustering configurations are responsible for the number and centroid energies of peaks of GDR spectra. Therefore, the GDR can be regarded as an effective probe to diagnose different α cluster configurations in light nuclei.

  12. Cooperative Self-Assembly of Carbazole Derivatives Driven by Multiple Dipole-Dipole Interactions.

    PubMed

    Ikeda, Toshiaki; Iijima, Tatsuya; Sekiya, Ryo; Takahashi, Osamu; Haino, Takeharu

    2016-08-01

    Carbazole possessing phenylisoxazoles self-assembled in a cooperative manner in decalin. X-ray crystal structure analysis revealed that the isoxazole dipoles align in a head-to-tail fashion. DFT calculations suggested that the linear array of dipoles induced the polarization of each dipole, leading to an increase in dipole-dipole interactions. This dipole polarization resulted in cooperative assembly. PMID:27391525

  13. Magnetic Field of a Dipole and the Dipole-Dipole Interaction

    ERIC Educational Resources Information Center

    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…

  14. Long-range dipole-dipole interaction and anomalous Förster energy transfer across a hyperbolic metamaterial

    NASA Astrophysics Data System (ADS)

    Biehs, S.-A.; Menon, Vinod M.; Agarwal, G. S.

    2016-06-01

    We study radiative energy transfer between a donor-acceptor pair across a hyperbolic metamaterial slab. We show that similar to a perfect lens a hyperbolic lens allows for giant energy transfer rates. For a realistic realization of a hyperbolic multilayer metamaterial we find an enhancement of up to three orders of magnitude with respect to the transfer rates across a plasmonic silver film of the same size especially for frequencies which coincide with the epsilon-near zero and the epsilon-near pole frequencies. Furthermore, we compare exact results based on the S -matrix method with results obtained from effective medium theory. Our finding of very large dipole-dipole interaction at distances of the order of a wavelength has important consequences for producing radiative heat transfer, quantum entanglement, etc.

  15. Combined Panofsky Quadrupole & Corrector Dipole

    SciTech Connect

    George Biallas; Nathan Belcher; David Douglas; Tommy Hiatt; Kevin Jordan

    2007-07-02

    Two styles of Panofsky Quadrupoles with integral corrector dipole windings are in use in the electron beam line of the Free Electron Laser at Jefferson Lab. We combined steering and focusing functions into single magnets, adding hundreds of Gauss-cm dipole corrector capability to existing quadrupoles because space is at a premium along the beam line. Superposing a one part in 100 dipole corrector field on a 1 part in 1000, weak (600 to 1000 Gauss) quadrupole is possible because the parallel slab iron yoke of the Panofsky Quadrupole acts as a window frame style dipole yoke. The dipole field is formed when two electrically floating “current sources”, designed and made at JLab, add and subtract current from the two opposite quadrupole current sheet windings parallel to the dipole field direction. The current sources also drive auxiliary coils at the yoke’s inner corners that improve the dipole field. Magnet measurements yielded the control system field maps that characterize the two types of fields. Field analysis using TOSCA, construction and wiring details, magnet measurements and reference for the current source are presented.

  16. Density-dependent covariant energy density functionals

    SciTech Connect

    Lalazissis, G. A.

    2012-10-20

    Relativistic nuclear energy density functionals are applied to the description of a variety of nuclear structure phenomena at and away fromstability line. Isoscalar monopole, isovector dipole and isoscalar quadrupole giant resonances are calculated using fully self-consistent relativistic quasiparticle randomphase approximation, based on the relativistic Hartree-Bogoliubovmodel. The impact of pairing correlations on the fission barriers in heavy and superheavy nuclei is examined. The role of pion in constructing desnity functionals is also investigated.

  17. Observation of Stueckelberg oscillations in dipole-dipole interactions

    SciTech Connect

    Ditzhuijzen, C. S. E. van; Tauschinsky, Atreju; Van Linden van den Heuvell, H. B.

    2009-12-15

    We have observed Stueckelberg oscillations in the dipole-dipole interaction between Rydberg atoms with an externally applied radio-frequency field. The oscillating rf field brings the interaction between cold Rydberg atoms in two separated volumes into resonance. We observe multiphoton transitions when varying the amplitude of the rf field and the static electric field offset. The angular momentum states we use show a quadratic Stark shift, which leads to a fundamentally 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. The oscillatory behavior of both functions corresponds to Stueckelberg oscillations, an interference effect described by the semiclassical Landau-Zener-Stueckelberg model. The measurements prove coherent dipole-dipole interaction during at least 0.6 mus.

  18. Fermion dipole moment and holography

    NASA Astrophysics Data System (ADS)

    Kulaxizi, Manuela; Rahman, Rakibur

    2015-12-01

    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.

  19. Dipole-dipole interaction between rubidium Rydberg atoms

    SciTech Connect

    Altiere, Emily; Fahey, Donald P.; Noel, Michael W.; Smith, Rachel J.; Carroll, Thomas J.

    2011-11-15

    Ultracold Rydberg atoms in a static electric field can exchange energy via the dipole-dipole interaction. The Stark effect shifts the energy levels of the atoms which tunes the energy exchange into resonance at specific values of the electric field (Foerster resonances). We excite rubidium atoms to Rydberg states by focusing either a 480 nm beam from a tunable dye laser or a pair of diode lasers into a magneto-optical trap. The trap lies at the center of a configuration of electrodes. We scan the electric field by controlling the voltage on the electrodes while measuring the fraction of atoms that interact. Dipole-dipole interaction spectra are presented for initially excited rubidium nd states for n=31 to 46 and for four different pairs of initially excited rubidium ns states. We also present the dipole-dipole interaction spectra for individual rubidium 32d (j, m{sub j}) fine structure levels that have been selectively excited. The data are compared to calculated spectra.

  20. Calculation of the energy loss for an electron passing near giant fullerenes

    NASA Astrophysics Data System (ADS)

    Henrard, L.; Lambin, Ph

    1996-11-01

    We present a theoretical analysis of the electron energy-loss spectra of isolated giant fullerenes. We use a macroscopic dielectric description of spherical onion-like fullerenes and a discrete dipole approximation (DDA) framework for tubular fullerenes. In the DDA model, an anisotropic dynamical polarizability is assigned to each carbon site. We stress the fundamental importance of the hollow character of giant fullerenes in the electron energy-loss resonances.

  1. Visualizing coherent intermolecular dipole-dipole coupling in real space.

    PubMed

    Zhang, Yang; Luo, Yang; Zhang, Yao; Yu, Yun-Jie; Kuang, Yan-Min; Zhang, Li; Meng, Qiu-Shi; Luo, Yi; Yang, Jin-Long; Dong, Zhen-Chao; Hou, J G

    2016-03-31

    Many important energy-transfer and optical processes, in both biological and artificial systems, depend crucially on excitonic coupling that spans several chromophores. Such coupling can in principle be described in a straightforward manner by considering the coherent intermolecular dipole-dipole interactions involved. However, in practice, it is challenging to directly observe in real space the coherent dipole coupling and the related exciton delocalizations, owing to the diffraction limit in conventional optics. Here we demonstrate that the highly localized excitations that are produced by electrons tunnelling from the tip of a scanning tunnelling microscope, in conjunction with imaging of the resultant luminescence, can be used to map the spatial distribution of the excitonic coupling in well-defined arrangements of a few zinc-phthalocyanine molecules. The luminescence patterns obtained for excitons in a dimer, which are recorded for different energy states and found to resemble σ and π molecular orbitals, reveal the local optical response of the system and the dependence of the local optical response on the relative orientation and phase of the transition dipoles of the individual molecules in the dimer. We generate an in-line arrangement up to four zinc-phthalocyanine molecules, with a larger total transition dipole, and show that this results in enhanced 'single-molecule' superradiance from the oligomer upon site-selective excitation. These findings demonstrate that our experimental approach provides detailed spatial information about coherent dipole-dipole coupling in molecular systems, which should enable a greater understanding and rational engineering of light-harvesting structures and quantum light sources. PMID:27029277

  2. Measuring the Forces between Magnetic Dipoles

    ERIC Educational Resources Information Center

    Gayetsky, Lisa E.; Caylor, Craig L.

    2007-01-01

    We describe a simple undergraduate lab in which students determine how the force between two magnetic dipoles depends on their separation. We consider the case where both dipoles are permanent and the case where one of the dipoles is induced by the field of the other (permanent) dipole. Agreement with theoretically expected results is quite good.

  3. Isovector and isoscalar tensor charges of the nucleon from lattice QCD

    DOE PAGESBeta

    Bhattacharya, Tanmoy; Cirigliano, Vincenzo; Cohen, Saul D.; Gupta, Rajan; Joseph, Anosh; Lin, Huey -Wen; Yoon, Boram

    2015-11-10

    Here, we present results for the isovector and flavor diagonal tensor charges gu–dT, guT, gdT, and gsT needed to probe novel tensor interactions at the TeV scale in neutron and nuclear β-decays and the contribution of the quark electric dipole moment (EDM) to the neutron EDM. The lattice QCD calculations were done using nine ensembles of gauge configurations generated by the MILC collaboration using the HISQ action with 2+1+1 dynamical flavors. These ensembles span three lattice spacings a ≈ 0.06, 0.09 and 0.12 fm and three quark masses corresponding to the pion masses Mπ ≈ 130, 220 and 310 MeV.more » Using estimates from these ensembles, we quantify all systematic uncertainties and perform a simultaneous extrapolation in the lattice spacing, volume and light quark masses for the connected contributions. The final estimates of the connected nucleon (proton) tensor charge for the isovector combination is gu–dT = 1.020(76) in the MS¯ scheme at 2 GeV. The additional disconnected quark loop contributions needed for the flavor-diagonal matrix elements are calculated using a stochastic estimator employing the truncated solver method with the all-mode-averaging technique. We find that the size of the disconnected contribution is smaller than the statistical error in the connected contribution. This allows us to bound the disconnected contribution and include it as an additional uncertainty in the flavor-diagonal charges. After a continuum extrapolation, we find guT = 0.774(66), gdT = –0.233(28) and gu+dT = 0.541(67). The strangeness tensor charge, that can make a significant contribution to the neutron EDM due to the large ratio ms/mu,d, is gsT = 0.008(9) in the continuum limit.« less

  4. Isovector and isoscalar tensor charges of the nucleon from lattice QCD

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Tanmoy; Cirigliano, Vincenzo; Cohen, Saul D.; Gupta, Rajan; Joseph, Anosh; Lin, Huey-Wen; Yoon, Boram; Precision Neutron Decay Matrix Elements Pndme Collaboration

    2015-11-01

    We present results for the isovector and flavor diagonal tensor charges gTu -d, gTu , gTd , and gTs needed to probe novel tensor interactions at the TeV scale in neutron and nuclear β -decays and the contribution of the quark electric dipole moment (EDM) to the neutron EDM. The lattice QCD calculations were done using nine ensembles of gauge configurations generated by the MILC collaboration using the HISQ action with 2 +1 +1 dynamical flavors. These ensembles span three lattice spacings a ≈0.06 , 0.09 and 0.12 fm and three quark masses corresponding to the pion masses Mπ≈130 , 220 and 310 MeV. Using estimates from these ensembles, we quantify all systematic uncertainties and perform a simultaneous extrapolation in the lattice spacing, volume and light quark masses for the connected contributions. The final estimates of the connected nucleon (proton) tensor charge for the isovector combination is gTu -d=1.020 (76 ) in the MS ¯ scheme at 2 GeV. The additional disconnected quark loop contributions needed for the flavor-diagonal matrix elements are calculated using a stochastic estimator employing the truncated solver method with the all-mode-averaging technique. We find that the size of the disconnected contribution is smaller than the statistical error in the connected contribution. This allows us to bound the disconnected contribution and include it as an additional uncertainty in the flavor-diagonal charges. After a continuum extrapolation, we find gTu=0.774 (66 ) , gTd=-0.233 (28 ) and gTu +d=0.541 (67 ) . The strangeness tensor charge, that can make a significant contribution to the neutron EDM due to the large ratio ms/mu ,d, is gTs=0.008 (9 ) in the continuum limit.

  5. Fluctuation properties of the strength function associated with the giant quadrupole resonance in {sup 208}Pb

    SciTech Connect

    Aiba, Hirokazu; Matsuo, Masayuki; Nishizaki, Shigeru; Suzuki, Toru

    2011-02-15

    We performed fluctuation analysis by means of the local scaling dimension for the strength function of the isoscalar (IS) giant quadrupole resonance (GQR) in {sup 208}Pb where the strength function is obtained by the shell model calculation including 1p1h and 2p2h configurations. It is found that at almost all energy scales, fluctuation of the strength function obeys the Gaussian orthogonal ensemble (GOE) random matrix theory limit. This is contrasted with the results for the GQR in {sup 40}Ca, where at the intermediate energy scale of about 1.7 MeV, a deviation from the GOE limit was detected. It is found that the physical origin for this different behavior of the local scaling dimension is ascribed to the difference in the properties of the damping process.

  6. Dispersion dipoles for coupled Drude oscillators

    NASA Astrophysics Data System (ADS)

    Odbadrakh, Tuguldur T.; Jordan, Kenneth D.

    2016-01-01

    We present the dispersion-induced dipole moments of coupled Drude oscillators obtained from two approaches. The first approach evaluates the dipole moment using the second-order Rayleigh-Schrödinger perturbation theory wave function allowing for dipole-dipole and dipole-quadrupole coupling. The second approach, based on response theory, employs an integral of the dipole-dipole polarizability of one oscillator and the dipole-dipole-quadrupole hyperpolarizability of the other oscillator over imaginary frequencies. The resulting dispersion dipoles exhibit an R-7 dependence on the separation between the two oscillators and are connected to the leading-order C6/R6 dispersion energy through the electrostatic Hellmann-Feynman theorem.

  7. Isovector and isoscalar tensor charges of the nucleon from lattice QCD

    SciTech Connect

    Bhattacharya, Tanmoy; Cirigliano, Vincenzo; Cohen, Saul D.; Gupta, Rajan; Joseph, Anosh; Lin, Huey -Wen; Yoon, Boram

    2015-11-10

    Here, we present results for the isovector and flavor diagonal tensor charges gu–dT, guT, gdT, and gsT needed to probe novel tensor interactions at the TeV scale in neutron and nuclear β-decays and the contribution of the quark electric dipole moment (EDM) to the neutron EDM. The lattice QCD calculations were done using nine ensembles of gauge configurations generated by the MILC collaboration using the HISQ action with 2+1+1 dynamical flavors. These ensembles span three lattice spacings a ≈ 0.06, 0.09 and 0.12 fm and three quark masses corresponding to the pion masses Mπ ≈ 130, 220 and 310 MeV. Using estimates from these ensembles, we quantify all systematic uncertainties and perform a simultaneous extrapolation in the lattice spacing, volume and light quark masses for the connected contributions. The final estimates of the connected nucleon (proton) tensor charge for the isovector combination is gu–dT = 1.020(76) in the MS¯ scheme at 2 GeV. The additional disconnected quark loop contributions needed for the flavor-diagonal matrix elements are calculated using a stochastic estimator employing the truncated solver method with the all-mode-averaging technique. We find that the size of the disconnected contribution is smaller than the statistical error in the connected contribution. This allows us to bound the disconnected contribution and include it as an additional uncertainty in the flavor-diagonal charges. After a continuum extrapolation, we find guT = 0.774(66), gdT = –0.233(28) and gu+dT = 0.541(67). The strangeness tensor charge, that can make a significant contribution to the neutron EDM due to the large ratio ms/mu,d, is gsT = 0.008(9) in the continuum limit.

  8. Prediction of isoscalar charmoniumlike structures in the hidden-charm di-eta decays of higher charmonia

    NASA Astrophysics Data System (ADS)

    Chen, Dian-Yong; Liu, Xiang; Matsuki, Takayuki

    2015-01-01

    Considering the situation that a single chiral particle, η is initially emitted, we study the hidden-charm di-eta decays of the charmoniumlike state Y(4660) and the predicted charmonium \\psi (4790), i.e., Y(4660)/\\psi (4790)\\to J/\\psi η η through the inetermediates η [{{D}(*)}{{\\bar{D}}(*)}] and/or η [Ds+(*)Ds-(*)], and answer the important question of whether there exist isoscalar charmoniumlike structures in the {{D}(*)}{{\\bar{D}}(*)} and/or Ds+(*)Ds-(*) channels. Our results predict that there will be enhancement structures near D{{\\bar{D}}*}, {{D}*}{{\\bar{D}}*} and {{D}s}\\bar{D}s* thresholds for Y(4660) and near {{D}*}{{\\bar{D}}*}, {{D}s}\\bar{D}s* and Ds*\\bar{D}s* thresholds for \\psi (4790) in the {{M}max }(J/\\psi η ) distributions of Y(4660)/\\psi (4790)\\to η η J/\\psi , respectively. These peaks are accessible in future experiments, especially BESIII, Belle, BaBar, and the forthcoming BelleII.

  9. Peripheral giant cell granuloma.

    PubMed

    Adlakha, V K; Chandna, P; Rehani, U; Rana, V; Malik, P

    2010-01-01

    Peripheral giant cell granuloma is a benign reactive lesion of gingiva. It manifests as a firm, soft, bright nodule or as a sessile or pedunculate mass. This article reports the management of peripheral giant cell granuloma in a 12-year-old boy by surgical excision. PMID:21273719

  10. Experimental static dipole-dipole polarizabilities of molecules

    NASA Astrophysics Data System (ADS)

    Hohm, U.

    2013-12-01

    A compilation of the static mean dipole-dipole polarizability α is given for 174 molecules. All data are evaluated from gas phase measurements. For some molecules like H2, N2, and O2 very precise experimental data exist with an uncertainty of better than 0.1%. In general however, the experimental error is much higher. There are also molecules like HI, CH2Cl2 or CH2Br2 for which the available data do not even overlap within their error bars. The present tabulations should be used if highly accurate experimental values are needed.

  11. Remote Sensing of Dipole Rings

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B.; Mied, Richard P.; Brown, James W.; Kirwan, A. D., Jr.

    1997-01-01

    Historical satellite-derived sea surface temperature (SST) data are reanalyzed with a zebra color palette and a thermal separatrix method. The new results from this reanalysis are as follows: (a) Thirteen observational sequences of six rings from the Gulf Stream and the Brazil Current, which have historically been interpreted as solitary vortices or monopoles are shown to have a dipolar character; (b) some of these dipole rings have been observed in the open ocean, thereby eliminating the possibility that they are sustained by topographic interactions with the continental slope; (c) whether interacting with other features or evolving as isolated circulations, dipoles are seen to rotate within a relatively narrow range of approximately 4-8 deg/day (interacting) and 10-11 deg/day (isolated); and (d) feature tracking delineates energetic fluid in both vortices and eliminates the possibility of interpreting dipole rings as transient features produced by active monopoles and patches of entrained fluid.

  12. Coherent and incoherent dipole-dipole interactions between atoms

    NASA Astrophysics Data System (ADS)

    Robicheaux, Francis

    2016-05-01

    Results will be presented on the collective interaction between atoms due to the electric dipole-dipole coupling between states of different parity on two different atoms. A canonical example of this effect is when the electronic state of one atom has S-character and the state of another atom has P-character. The energy difference between the two states plays an important role in the interaction since the change in energy determines the wave number of a photon that would cause a transition between the states. If the atoms are much closer than the wave length of this photon, then the dipole-dipole interaction is in the near field and has a 1 /r3 dependence on atomic separation. If the atoms are farther apart than the wave length, then the interaction is in the far field and has a 1 / r dependence. When many atoms interact, collective effects can dominate the system with the character of the collective effect depending on whether the atomic separation leads to near field or far field coupling. As an example of the case where the atoms are in the far field, the line broadening of transitions and strong deviations from the Beer-Lambert law in a diffuse gas will be presented. As an example of near field collective behavior, the radiative properties of a Rydberg gas will be presented. Based upon work supported by the National Science Foundation under Grant No. 1404419-PHY in collaboration with R.T. Sutherland.

  13. Dipole relaxation in an electric field

    NASA Astrophysics Data System (ADS)

    Neumann, Richard M.

    1980-07-01

    From Boltzmann's equation, S=k lnΩ, an expression for the orientational entropy, S of a rigid rod (electric dipole) is derived. The free energy of the dipole in an electric field is then calculated as a function of both the dipole's average orientation and the field strength. Application of the equilibrium criterion to the free energy yields the field dependence of the entropy of the dipole. Irreversible thermodynamics is used to derive the general form of the equation of motion of the dipole's average orientation. Subsequent application of Newton's second law of motion produces Debye's classical expression for the relaxation of an electric dipole in a viscous medium.

  14. Numerical Based Linear Model for Dipole Magnets

    SciTech Connect

    Li,Y.; Krinsky, S.; Rehak, M.

    2009-05-04

    In this paper, we discuss an algorithm for constructing a numerical linear optics model for dipole magnets from a 3D field map. The difference between the numerical model and K. Brown's analytic approach is investigated and clarified. It was found that the optics distortion due to the dipoles' fringe focusing must be properly taken into account to accurately determine the chromaticities. In NSLS-II, there are normal dipoles with 35-mm gap and dipoles for infrared sources with 90-mm gap. This linear model of the dipole magnets is applied to the NSLS-II lattice design to match optics parameters between the DBA cells having dipoles with different gaps.

  15. Unstable giant gravitons

    SciTech Connect

    Mello Koch, Robert de; Ives, Norman; Smolic, Jelena; Smolic, Milena

    2006-03-15

    We find giant graviton solutions in Frolov's three parameter generalization of the Lunin-Maldacena background. The background we study has {gamma}-tilde{sub 1}=0 and {gamma}-tilde{sub 2}={gamma}-tilde{sub 3}={gamma}-tilde. This class of backgrounds provides a nonsupersymmetric example of the gauge theory/gravity correspondence that can be tested quantitatively, as recently shown by Frolov, Roiban, and Tseytlin. The giant graviton solutions we find have a greater energy than the point gravitons, making them unstable states. Despite this, we find striking quantitative agreement between the gauge theory and gravity descriptions of open strings attached to the giant.

  16. Induced dipole-dipole interactions in light diffusion from point dipoles

    NASA Astrophysics Data System (ADS)

    Cherroret, Nicolas; Delande, Dominique; van Tiggelen, Bart A.

    2016-07-01

    We develop a perturbative treatment of induced dipole-dipole interactions in the diffusive transport of electromagnetic waves through disordered atomic clouds. The approach is exact at order 2 in the atomic density and accounts for the vector character of light. It is applied to the calculations of the electromagnetic energy stored in the atomic cloud, which modifies the energy transport velocity, and of the light scattering and transport mean free paths. Results are compared to those obtained from a purely scalar model for light.

  17. Measurement of the Dipole Polarizability of the Unstable Neutron-Rich Nucleus Ni68

    NASA Astrophysics Data System (ADS)

    Rossi, D. M.; Adrich, P.; Aksouh, F.; Alvarez-Pol, H.; Aumann, T.; Benlliure, J.; Böhmer, M.; Boretzky, K.; Casarejos, E.; Chartier, M.; Chatillon, A.; Cortina-Gil, D.; Datta Pramanik, U.; Emling, H.; Ershova, O.; Fernandez-Dominguez, B.; Geissel, H.; Gorska, M.; Heil, M.; Johansson, H. T.; Junghans, A.; Kelic-Heil, A.; Kiselev, O.; Klimkiewicz, A.; Kratz, J. V.; Krücken, R.; Kurz, N.; Labiche, M.; Le Bleis, T.; Lemmon, R.; Litvinov, Yu. A.; Mahata, K.; Maierbeck, P.; Movsesyan, A.; Nilsson, T.; Nociforo, C.; Palit, R.; Paschalis, S.; Plag, R.; Reifarth, R.; Savran, D.; Scheit, H.; Simon, H.; Sümmerer, K.; Wagner, A.; Waluś, W.; Weick, H.; Winkler, M.

    2013-12-01

    The E1 strength distribution in Ni68 has been investigated using Coulomb excitation in inverse kinematics at the RB3-LAND setup and by measuring the invariant mass in the one- and two-neutron decay channels. The giant dipole resonance and a low-lying peak (pygmy dipole resonance) have been observed at 17.1(2) and 9.55(17) MeV, respectively. The measured dipole polarizability is compared to relativistic random phase approximation calculations yielding a neutron-skin thickness of 0.17(2) fm. A method and analysis applicable to neutron-rich nuclei has been developed, allowing for a precise determination of neutron skins in nuclei as a function of neutron excess.

  18. Dipole-strength distributions up to the particle-separation energies and photodissociation of Mo isotopes

    NASA Astrophysics Data System (ADS)

    Schwengner, R.; Benouaret, N.; Beyer, R.; Dönau, F.; Erhard, M.; Frauendorf, S.; Grosse, E.; Junghans, A. R.; Klug, J.; Kosev, K.; Nair, C.; Nankov, N.; Rusev, G.; Schilling, K. D.; Wagner, A.

    2007-05-01

    Dipole-strength distributions in the nuclides 92Mo, 98Mo and 100Mo have been investigated in photon-scattering experiments with bremsstrahlung at the superconducting electron accelerator ELBE of the Forschungszentrum Rossendorf. A simulation of γ cascades was performed in order to estimate the distribution of inelastic transitions to low-lying states and thus to deduce the primary dipole-strength distribution up to the neutron-separation energies. The absorption cross sections obtained connect smoothly to ( γ, n) cross sections and give novel information about the low-energy tail of the Giant Dipole Resonance below the neutron-separation energies. The experimental cross sections are compared with predictions of a Quasiparticle-Random-Phase Approximation (QRPA) in a deformed basis. Photoactivation experiments were performed at various electron energies to study the 92Mo( γ, n), 92Mo( γ, p), 92Mo( γ, α) and 100Mo( γ, n) reactions. The deduced activation yields are compared with theoretical predictions.

  19. Measurement of the dipole polarizability of the unstable neutron-rich nucleus 68Ni.

    PubMed

    Rossi, D M; Adrich, P; Aksouh, F; Alvarez-Pol, H; Aumann, T; Benlliure, J; Böhmer, M; Boretzky, K; Casarejos, E; Chartier, M; Chatillon, A; Cortina-Gil, D; Datta Pramanik, U; Emling, H; Ershova, O; Fernandez-Dominguez, B; Geissel, H; Gorska, M; Heil, M; Johansson, H T; Junghans, A; Kelic-Heil, A; Kiselev, O; Klimkiewicz, A; Kratz, J V; Krücken, R; Kurz, N; Labiche, M; Le Bleis, T; Lemmon, R; Litvinov, Yu A; Mahata, K; Maierbeck, P; Movsesyan, A; Nilsson, T; Nociforo, C; Palit, R; Paschalis, S; Plag, R; Reifarth, R; Savran, D; Scheit, H; Simon, H; Sümmerer, K; Wagner, A; Waluś, W; Weick, H; Winkler, M

    2013-12-13

    The E1 strength distribution in 68Ni has been investigated using Coulomb excitation in inverse kinematics at the R3B-LAND setup and by measuring the invariant mass in the one- and two-neutron decay channels. The giant dipole resonance and a low-lying peak (pygmy dipole resonance) have been observed at 17.1(2) and 9.55(17) MeV, respectively. The measured dipole polarizability is compared to relativistic random phase approximation calculations yielding a neutron-skin thickness of 0.17(2) fm. A method and analysis applicable to neutron-rich nuclei has been developed, allowing for a precise determination of neutron skins in nuclei as a function of neutron excess. PMID:24483648

  20. New bound on neutrino dipole moments from globular-cluster stars

    NASA Technical Reports Server (NTRS)

    Raffelt, Georg G.

    1990-01-01

    Neutrino dipole moments mu(nu) would increase the core mass of red giants at the helium flash by delta(Mc) = 0.015 solar mass x mu(nu)/10 to the -12th muB (where muB is the Bohr magneton) because of enhanced neutrino losses. Existing measurements of the bolometric magnitudes of the brightest red giants in 26 globular clusters, number counts of horizontal-branch stars and red giants in 15 globular clusters, and statistical parallax determinations of field RR Lyr luminosities yield delta(Mc) = 0.009 + or - 0.012 solar mass, so that conservatively mu(nu) is less than 3 x 10 to the -12th muB.

  1. Mutual impedance computation between printed dipoles

    NASA Astrophysics Data System (ADS)

    Alexopoulos, N. G.; Rana, I. E.

    1981-01-01

    The mutual impedance between microstrip dipoles printed on a grounded substrate is computed. Results for the microstrip dipoles in broadside, collinear, and echelon arrangements are presented. The significance of surface wave to mutual coupling is discussed.

  2. Attosecond delay of xenon 4 d photoionization at the giant resonance and Cooper minimum

    NASA Astrophysics Data System (ADS)

    Magrakvelidze, Maia; Madjet, Mohamed El-Amine; Chakraborty, Himadri S.

    2016-07-01

    A Kohn-Sham time-dependent local-density-functional scheme is utilized to predict attosecond time delays of xenon 4 d photoionization that involves the 4 d giant dipole resonance and Cooper minimum. The fundamental effect of electron correlations to uniquely determine the delay at both regions is demonstrated. In particular, for the giant dipole resonance, the delay underpins strong collective effect, emulating the recent prediction at C60 giant plasmon resonance [T. Barillot et al., Phys. Rev. A 91, 033413 (2015), 10.1103/PhysRevA.91.033413]. For the Cooper minimum, a qualitative similarity with a photorecombination experiment near argon 3 p minimum [S. B. Schoun et al., Phys. Rev. Lett. 112, 153001 (2014), 10.1103/PhysRevLett.112.153001] is found. The result should encourage attosecond measurements of Xe 4 d photoemission.

  3. Giant distal humeral geode.

    PubMed

    Maher, M M; Kennedy, J; Hynes, D; Murray, J G; O'Connell, D

    2000-03-01

    We describe the imaging features of a giant geode of the distal humerus in a patient with rheumatoid arthritis, which presented initially as a pathological fracture. The value of magnetic resonance imaging in establishing this diagnosis is emphasized. PMID:10794554

  4. Giant Subclavian Artery Aneurysm.

    PubMed

    Counts, Sarah; Zeeshan, Ahmad; Elefteriades, John

    2016-06-01

    We report the case of a 37-year-old construction executive presenting with chest pain, shortness of breath, and dizziness on exertion secondary to a giant left subclavian artery aneurysm and aortic valvular disease. PMID:27231430

  5. The Next Giant Step

    NASA Video Gallery

    Artist Robert McCall painted "The Next Giant Step" in 1979 to commemorate the heroism and courage of spaceflight pioneers. Located in the lobby of Johnson's building 2, the mural depicts America's ...

  6. The Giant Cell.

    ERIC Educational Resources Information Center

    Stockdale, Dennis

    1998-01-01

    Provides directions for the construction of giant plastic cells, including details for building and installing the organelles. Also contains instructions for preparing the ribosomes, nucleolus, nucleus, and mitochondria. (DDR)

  7. Study of the Pygmy Dipole Resonance in {sup 124}Sn by means of the ({alpha},{alpha}'{gamma}) reaction

    SciTech Connect

    Endres, J.; Zilges, A.; Pietralla, N.; Savran, D.; Sonnabend, K.; Harakeh, M. N.; Stoica, V.; Woertche, H.; Butler, P.; Herzberg, R. D.; Scheck, M.; Kruecken, R.; Popescu, L.; Harissopulos, S.; Lagoyannis, A.

    2009-01-28

    In recent years {alpha}-{gamma} coincidence experiments at 136 MeV incident energy on {sup 48}Ca, {sup 140}Ce, {sup 138}Ba and {sup 124}Sn were performed at the KVI in Groningen to study the isospin character of electric dipole excitations below the particle threshold, frequently called Pygmy Dipole Resonance (PDR). An array of HPGe {gamma}-detectors has been used in coincidence with the Big-Bite Spectrometer (BBS) and a resolution of about 10 keV in the {gamma}-ray energy has been achieved. The results show that the excitation patterns of the PDR in the ({alpha},{alpha}') reaction seem to differ significantly from results obtained in Nuclear Resonance Fluorescence (NRF)({gamma},{gamma}') measurements. The PDR, which until now has been assigned to one excitation mode, splits up into two parts: One that is excited in ({alpha},{alpha}'{gamma}) and ({gamma},{gamma}') reactions (denoting a dominant isoscalar character), and one that is only excited in ({gamma},{gamma}')(denoting a dominant isovector character). This indicates that two different excitation mechanisms produce these low-lying E1 excitations [1], The preliminary results of the latest measurements on the N = 82 nucleus {sup 138}Ba and the Z = 50 nucleus {sup 124}Sn show that this break up into two parts is a common feature of the PDR in semi-magic nuclei.

  8. Study of the Pygmy Dipole Resonance in 124Sn by means of the (α,α'γ) reaction

    NASA Astrophysics Data System (ADS)

    Endres, J.; Zilges, A.; Pietralla, N.; Savran, D.; Sonnabend, K.; Harakeh, M. N.; Stoica, V.; Wörtche, H.; Butler, P.; Herzberg, R. D.; Scheck, M.; Krü; cken, R.; Popescu, L.; Harissopulos, S.; Lagoyannis, A.

    2009-01-01

    In recent years α-γ coincidence experiments at 136 MeV incident energy on 48Ca, 140Ce, 138Ba and 124Sn were performed at the KVI in Groningen to study the isospin character of electric dipole excitations below the particle threshold, frequently called Pygmy Dipole Resonance (PDR). An array of HPGe γ-detectors has been used in coincidence with the Big-Bite Spectrometer (BBS) and a resolution of about 10 keV in the γ-ray energy has been achieved. The results show that the excitation patterns of the PDR in the (α,α') reaction seem to differ significantly from results obtained in Nuclear Resonance Fluorescence (NRF) (γ,γ') measurements. The PDR, which until now has been assigned to one excitation mode, splits up into two parts: One that is excited in (α,α'γ) and (γ,γ') reactions (denoting a dominant isoscalar character), and one that is only excited in (γ,γ') (denoting a dominant isovector character). This indicates that two different excitation mechanisms produce these low-lying E1 excitations [1], The preliminary results of the latest measurements on the N = 82 nucleus 138Ba and the Z = 50 nucleus 124Sn show that this break up into two parts is a common feature of the PDR in semi-magic nuclei.

  9. Critical behavior of isotropic three-dimensional systems with dipole-dipole interactions

    SciTech Connect

    Belim, S. M.

    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.

  10. Juno and Cassini Proximal: Giant Steps Towards Understanding Giant Planets

    NASA Astrophysics Data System (ADS)

    Stevenson, D. J.

    2014-12-01

    In 2016-17, Juno and Cassini Proximal will provide comparable large advances in our understanding of the interiors of Jupiter and Saturn. Both will provide high accuracy gravity and magnetic field data, while Juno will in addition determine the water abundance deep in the Jovian atmosphere, essential for understanding of giant planet formation and the density of the outer envelope (needed to construct interior models). Although Jupiter and Saturn are both gas giants, they differ in important ways (magnetic field, strength of zonal flows, enrichment in heavy elements, and probably the distribution of helium within). The opportunity to contrast and compare will be invaluable. Juno and Cassini are expected to determine the gravity field to about a part in 109 though with different spatial coverage and with less accurate determination near the poles. The determination of Jupiter's likely central concentration of heavy elements is particularly challenging because it is only a few percent at most of the total mass and yet important for understanding Jupiter's formation, which in turn likely determined the architecture of our solar system. This determination will be done from gravity, water determination and magnetic field and also aided by advances in our understanding of material properties. The corresponding determination for Saturn may prove easier (because the heavy element enrichment is a larger fraction of the mass) though complicated by lack of knowledge of water abundance and the need to identify a more precise value for the deep rotation of the planet (difficult for Saturn because of the lack of a measurable magnetic dipole tilt thus far). For both planets, the higher harmonics of gravity will likely be controlled by differential rotation (the zonal flows) and this will tell us their depth, an issue of major interest in the dynamics of these bodies. The magnetic field structure for Jupiter will be determined to higher accuracy than the Earth's core field (since

  11. Efficient treatment of induced dipoles.

    PubMed

    Simmonett, Andrew C; Pickard, Frank C; Shao, Yihan; Cheatham, Thomas E; Brooks, Bernard R

    2015-08-21

    Most existing treatments of induced dipoles in polarizable molecular mechanics force field calculations use either the self-consistent variational method, which is solved iteratively, or the "direct" approximation that is non-iterative as a result of neglecting coupling between induced dipoles. The variational method is usually implemented using assumptions that are only strictly valid under tight convergence of the induced dipoles, which can be computationally demanding to enforce. In this work, we discuss the nature of the errors that result from insufficient convergence and suggest a strategy that avoids such problems. Using perturbation theory to reintroduce the mutual coupling into the direct algorithm, we present a computationally efficient method that combines the precision of the direct approach with the accuracy of the variational approach. By analyzing the convergence of this perturbation series, we derive a simple extrapolation formula that delivers a very accurate approximation to the infinite order solution at the cost of only a few iterations. We refer to the new method as extrapolated perturbation theory. Finally, we draw connections to our previously published permanent multipole algorithm to develop an efficient implementation of the electric field and Thole terms and also derive some necessary, but not sufficient, criteria that force field parameters must obey. PMID:26298123

  12. Efficient treatment of induced dipoles

    PubMed Central

    Simmonett, Andrew C.; Pickard, Frank C.; Shao, Yihan; Cheatham, Thomas E.; Brooks, Bernard R.

    2015-01-01

    Most existing treatments of induced dipoles in polarizable molecular mechanics force field calculations use either the self-consistent variational method, which is solved iteratively, or the “direct” approximation that is non-iterative as a result of neglecting coupling between induced dipoles. The variational method is usually implemented using assumptions that are only strictly valid under tight convergence of the induced dipoles, which can be computationally demanding to enforce. In this work, we discuss the nature of the errors that result from insufficient convergence and suggest a strategy that avoids such problems. Using perturbation theory to reintroduce the mutual coupling into the direct algorithm, we present a computationally efficient method that combines the precision of the direct approach with the accuracy of the variational approach. By analyzing the convergence of this perturbation series, we derive a simple extrapolation formula that delivers a very accurate approximation to the infinite order solution at the cost of only a few iterations. We refer to the new method as extrapolated perturbation theory. Finally, we draw connections to our previously published permanent multipole algorithm to develop an efficient implementation of the electric field and Thole terms and also derive some necessary, but not sufficient, criteria that force field parameters must obey. PMID:26298123

  13. Relativistic Dipole Matrix Element Zeros

    NASA Astrophysics Data System (ADS)

    Lajohn, L. A.; Pratt, R. H.

    2002-05-01

    There is a special class of relativistic high energy dipole matrix element zeros (RZ), whose positions with respect to photon energy ω , only depend on the bound state l quantum number according to ω^0=mc^2/(l_b+1) (independent of primary quantum number n, nuclear charge Z, central potential V and dipole retardation). These RZ only occur in (n,l_b,j_b)arrow (ɛ , l_b+1,j_b) transitions such as ns_1/2arrow ɛ p_1/2; np_3/2arrow ɛ d_3/2: nd_5/2arrow ɛ f_5/2 etc. The nonrelativistic limit of these matrix elements can be established explicitly in the Coulomb case. Within the general matrix element formalism (such as that in [1]); when |κ | is substituted for γ in analytic expressions for matrix elements, the zeros remain, but ω^0 now becomes dependent on n and Z. When the reduction to nonrelativistic form is completed by application of the low energy approximation ω mc^2 mc^2, the zeros disappear. This nonzero behavior was noted in nonrelativistic dipole Coulomb matrix elements by Fano and Cooper [2] and later proven by Oh and Pratt[3]. (J. H. Scofield, Phys. Rev. A 40), 3054 (1989 (U. Fano and J. W. Cooper, Rev. Mod. Phys. 40), 441 (1968). (D. Oh and R. H. Pratt, Phys. Rev. A 34), 2486 (1986); 37, 1524 (1988); 45, 1583 (1992).

  14. Efficient treatment of induced dipoles

    NASA Astrophysics Data System (ADS)

    Simmonett, Andrew C.; Pickard, Frank C.; Shao, Yihan; Cheatham, Thomas E.; Brooks, Bernard R.

    2015-08-01

    Most existing treatments of induced dipoles in polarizable molecular mechanics force field calculations use either the self-consistent variational method, which is solved iteratively, or the "direct" approximation that is non-iterative as a result of neglecting coupling between induced dipoles. The variational method is usually implemented using assumptions that are only strictly valid under tight convergence of the induced dipoles, which can be computationally demanding to enforce. In this work, we discuss the nature of the errors that result from insufficient convergence and suggest a strategy that avoids such problems. Using perturbation theory to reintroduce the mutual coupling into the direct algorithm, we present a computationally efficient method that combines the precision of the direct approach with the accuracy of the variational approach. By analyzing the convergence of this perturbation series, we derive a simple extrapolation formula that delivers a very accurate approximation to the infinite order solution at the cost of only a few iterations. We refer to the new method as extrapolated perturbation theory. Finally, we draw connections to our previously published permanent multipole algorithm to develop an efficient implementation of the electric field and Thole terms and also derive some necessary, but not sufficient, criteria that force field parameters must obey.

  15. Electric Dipole Moments of Light Nuclei and the Implications for CP Violation

    NASA Astrophysics Data System (ADS)

    Gibson, B. F.; Afnan, I. R.

    2013-03-01

    A definitive measurement of an electric dipole moment (EDM) would likely imply new physics beyond the standard model. Although the standard model strong interaction term could theoretically produce an EDM of any size, that it is constrained by the current neutron EDM limit to be some 10 orders of magnitude smaller than 1 suggests that the electroweak sector and CP violation will be the source of a measurable EDM. The weak interaction standard model EDM is itself orders of magnitude smaller than contemporary experiments can measure. Direct measurement of the neutron EDM lies in the next decade; measurement of the proton EDM could well come first. A BNL proposal for an electrostatic storage ring measurement lies in the offing. Unless the EDM proves to be an isoscalar, one will need other measurements to separate the isoscalar, isovector, and isotensor components. Measurement of a nuclear EDM will be required: 2H, 3H, or 3He being the simplest nuclear systems. A storage ring measurement of the triton EDM could be accomplished in a manner analogous to that proposed for the proton. However, the deuteron EDM measurement offers certain advantages, even though the experiment would be more complex, involving electric and magnetic fields, than that required for the proton and triton. The COSY facility in the Forschungszentrum Juelich is almost an ideal facility to house such an experiment; one could also measure in the same ring the EDM for the proton and He. The deuteron is the one nucleus for which exact model calculations can easily be performed. We briefly explore the model dependence of deuteron EDM calculations. Using a separable potential formulation of the Hamiltonian, we examine the sensitivity of the deuteron EDM to variations in the nucleon-nucleon interaction, including contemporary potential models, and we explore the dependence upon intermediate state multiple scattering in the 3P1 channel. We investigate the tensor force contribution to the model results and

  16. RHIC spin flipper AC dipole controller

    SciTech Connect

    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.

  17. Giant perigenital seborrheic keratosis

    PubMed Central

    Bandyopadhyay, Debabrata; Saha, Abanti; Mishra, Vivek

    2015-01-01

    Seborrheic keratosis (SK) is a very common benign epidermal proliferation that is prevalent in all races. Most commonly occurring on the trunk, face, scalp, and the extremities, they can occur anywhere on the body except the palms and soles. The most common appearance is that of a very superficial verrucous plaque which appears to be stuck on the surface. Giant lesions are very rare, and their location on the genital area is rarer still. We report here a case of multiple giant SK lesions in a 59-year-old man. PMID:25657917

  18. An Innocent Giant

    PubMed Central

    Solanki, Lakhan Singh; Dhingra, Mandeep; Raghubanshi, Gunjan; Thami, Gurvinder Pal

    2014-01-01

    A cutaneous horn (cornu cutaneum) is a protrusion from the skin composed of a cornified material. It may be associated with a benign, premalignant, or malignant lesion at the base, masking numerous dermatoses. In a 24-year-old female, a giant cutaneous horn arising from a seborrheic keratosis located on the leg is presented. This case has been reported to emphasize that a giant cutaneous horn may also occur in young patients, even in photoprotected areas, and are not always associated with malignancy. PMID:25484426

  19. Giant perigenital seborrheic keratosis.

    PubMed

    Bandyopadhyay, Debabrata; Saha, Abanti; Mishra, Vivek

    2015-01-01

    Seborrheic keratosis (SK) is a very common benign epidermal proliferation that is prevalent in all races. Most commonly occurring on the trunk, face, scalp, and the extremities, they can occur anywhere on the body except the palms and soles. The most common appearance is that of a very superficial verrucous plaque which appears to be stuck on the surface. Giant lesions are very rare, and their location on the genital area is rarer still. We report here a case of multiple giant SK lesions in a 59-year-old man. PMID:25657917

  20. AutoDipole - Automated generation of dipole subtraction terms -

    NASA Astrophysics Data System (ADS)

    Hasegawa, K.; Moch, S.; Uwer, P.

    2010-10-01

    We present an automated generation of the subtraction terms for next-to-leading order QCD calculations in the Catani-Seymour dipole formalism. For a given scattering process with n external particles our Mathematica package generates all dipole terms, allowing for both massless and massive dipoles. The numerical evaluation of the subtraction terms proceeds with MadGraph, which provides Fortran code for the necessary scattering amplitudes. Checks of the numerical stability are discussed. Program summaryProgram title: AutoDipole Catalogue identifier: AEGO_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEGO_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 138 042 No. of bytes in distributed program, including test data, etc.: 1 117 665 Distribution format: tar.gz Programming language: Mathematica and Fortran Computer: Computers running Mathematica (version 7.0) Operating system: The package should work on every Linux system supported by Mathematica. Detailed tests have been performed on Scientific Linux as supported by DESY and CERN and on openSUSE and Debian. RAM: Depending on the complexity of the problem, recommended at least 128 MB RAM Classification: 11.5 External routines: MadGraph (including HELAS library) available under http://madgraph.hep.uiuc.edu/ or http://madgraph.phys.ucl.ac.be/ or http://madgraph.roma2.infn.it/. A copy of the tar file, MG_ME_SA_V4.4.30, is included in the AutoDipole distribution package. Nature of problem: Computation of next-to-leading order QCD corrections to scattering cross sections, regularization of real emission contributions. Solution method: Catani-Seymour subtraction method for massless and massive partons [1,2]; Numerical evaluation of subtracted matrix elements interfaced to MadGraph [3-5] (stand-alone version) using

  1. Broad-band UHF dipole array

    NASA Technical Reports Server (NTRS)

    Bailey, M. C.

    1985-01-01

    A 6X6 array of fan-dipoles was designed to operate in the 510 to 660 MHz frequency range for aircraft flight test and evaluation of a UHF radiometer system. A broad-band dipole design operating near the first resonance is detailed. Measured VSWR and radiation patterns for the dipole array demonstrate achievable bandwidths in the 35 percent to 40 percent range.

  2. Electroluminescence of Giant Stretchability.

    PubMed

    Yang, Can Hui; Chen, Baohong; Zhou, Jinxiong; Chen, Yong Mei; Suo, Zhigang

    2016-06-01

    A new type of electroluminescent device achieves giant stretchability by integrating electronic and ionic components. The device uses phosphor powders as electroluminescent materials, and hydrogels as stretchable and transparent ionic conductors. Subject to cyclic voltage, the phosphor powders luminesce, but the ionic conductors do not electrolyze. The device produces constant luminance when stretched up to an area strain of 1500%. PMID:26610277

  3. A giant ureteric calculus

    PubMed Central

    Rathod, Rajiv; Bansal, Prashant; Gutta, Srinivas

    2013-01-01

    Ureteric stones are usually small and symptomatic. We present a case of a 35-year old female who presented with minimally symptomatic right distal ureteric calculus with proximal hydroureteronephrosis. Laparoscopic right ureterolithotomy was performed and a giant ureteric calculus measuring 11 cm Χ 1.5 cm, weighing 40 g was retrieved. PMID:24082453

  4. Giant urethral calculus

    PubMed Central

    Kotkar, Kunal; Thakkar, Ravi; Songra, MC

    2011-01-01

    Primary urethral calculus is rarely seen and is usually encountered in men with urethral stricture or diverticulum. We present a case of giant urethral calculus secondary to a urethral stricture in a man. The patient was treated with calculus extraction with end to end urethroplasty. PMID:24950400

  5. Juvenile giant fibroadenoma

    PubMed Central

    Yagnik, Vipul D.

    2011-01-01

    Fibroadenomas are benign solid tumor associated with aberration of normal lobular development. Juvenile giant fibroadenoma is usually single and >5 cm in size /or >500 gms in weight. Important differential diagnoses are: phyllodes tumor and juvenile gigantomastia. Simple excision is the treatment of choice. PMID:24765310

  6. A giant ureteric calculus.

    PubMed

    Rathod, Rajiv; Bansal, Prashant; Gutta, Srinivas

    2013-07-01

    Ureteric stones are usually small and symptomatic. We present a case of a 35-year old female who presented with minimally symptomatic right distal ureteric calculus with proximal hydroureteronephrosis. Laparoscopic right ureterolithotomy was performed and a giant ureteric calculus measuring 11 cm Χ 1.5 cm, weighing 40 g was retrieved. PMID:24082453

  7. Plasmonic nanohelix metamaterials with tailorable giant circular dichroism

    NASA Astrophysics Data System (ADS)

    Gibbs, J. G.; Mark, A. G.; Eslami, S.; Fischer, P.

    2013-11-01

    Plasmonic nanohelix arrays are shown to interact with electromagnetic fields in ways not typically seen with ordinary matter. Chiral metamaterials (CMMs) with feature sizes small with respect to the wavelength of visible light are a promising route to experimentally achieve such phenomena as negative refraction without the need for simultaneously negative ɛ and μ. Here we not only show that giant circular dichroism in the visible is achievable with hexagonally arranged plasmonic nanohelix arrays, but that we can precisely tune the optical activity via morphology and lattice spacing. The discrete dipole approximation is implemented to support experimental data.

  8. Magnetic Field Generation and Zonal Flows in the Gas Giants

    NASA Astrophysics Data System (ADS)

    Duarte, L.; Wicht, J.; Gastine, T.

    2013-12-01

    The surface dynamics of Jupiter and Saturn is dominated by a banded system of fierce zonal winds. The depth of these winds remains unclear but they are thought to be confined to the very outer envelopes where hydrogen remains molecular and the electrical conductivity is negligible. The dynamo responsible for the dipole dominated magnetic fields of both Gas Giants, on the other hand, likely operates in the deeper interior where hydrogen assumes a metallic state. We present numerical simulations that attempt to model both the zonal winds and the interior dynamo action in an integrated approach. Using the anelastic version of the MHD code MagIC, we explore the effects of density stratification and radial electrical conductivity variations. The electrical conductivity is assumed to remain constant in the thicker inner metallic region and decays exponentially towards the outer boundary throughout the molecular envelope. Our results show that the combination of stronger density stratification (Δρ≈55) and a weaker conducting outer layer is essential for reconciling dipole dominated dynamo action and a fierce equatorial zonal jet. Previous simulations with homogeneous electrical conductivity show that both are mutually exclusive, with solutions either having strong zonal winds and multipolar magnetic fields or weak zonal winds and dipole dominated magnetic fields. The particular setup explored here allows the equatorial jet to remain confined to the weaker conducting region where is does not interfere with the deeper seated dynamo action. The equatorial jet can afford to remain geostrophic and reaches throughout the whole shell. This is not an option for the additional mid to higher latitude jets, however. In dipole dominated dynamo solutions, appropriate for the Gas Giants, zonal flows remain very faint in the deeper dynamo region but increase in amplitude in the weakly conducting outer layer in some of our simulations. This suggests that the mid to high latitude jets

  9. Top quark electromagnetic dipole moments

    NASA Astrophysics Data System (ADS)

    Bouzas, Antonio O.; Larios, F.

    2015-11-01

    The magnetic and electric dipole moments of the top quark are constrained indirectly by the Br(B → Xsγ) and the ACP(B → Xsγ) measurements. They can also be tested by top quark production and decay processes. The recent measurement of production by CDF are used to set direct constraints. The B → Xsγ measurements by themselves define an allowed parameter region that sets up stringent constraints on both dipole moments. The measurement by CDF has a ∼ 37% error that is too large to set any competitive bounds, for which a much lower 5% error would be required. For the LHC it is found that with its higher energy the same measurement could indeed further constrain the allowed parameter region given by the B → Xsγ measurement [1]. In addition, the proposed LHeC experiment (electron- proton) could provide even more stringent constraints than the LHC via the photoproduction channel [2].

  10. Nuclear Electric Dipole Moment Calculations

    NASA Astrophysics Data System (ADS)

    Haxton, Wick

    2010-11-01

    One of the most important constraints on CP violation in the nucleon and NN interaction is provided by electric dipole moment (EDM) limits for neutral diamagnetic atoms, particularly 199Hg. To extract CP-violating couplings from experiment, one must relate the atomic EDM to the underlying nuclear CP-odd moments, a task complicated by the atomic response, which largely shields the nucleus from the applied external electric field. The residual response -- the Schiff moment -- depends on corrections such as the finite size of the nucleus. Conventional Schiff-moment calculations have largely ignored one consequence of the screening: the cancellation between direct and polarization diagrams, which yields an answer that is suppressed by two powers of RN/RA, where RN and RA are the nuclear and atomic sizes, requires one to identify all other terms that contribute to the same order in the RN/RA power counting. We show that such terms arise from nuclear excitations associated with the dipole charge and transverse electric multipole operators, and discuss the consequences. We also describe higher T-odd moments that contribute up to the same order in the counting, and point out interesting nuclear structure and experimental consequences.

  11. Spectral Distortions of the CMB Dipole

    NASA Astrophysics Data System (ADS)

    Balashev, S. A.; Kholupenko, E. E.; Chluba, J.; Ivanchik, A. V.; Varshalovich, D. A.

    2015-09-01

    We consider the distortions of the cosmic microwave background (CMB) dipole anisotropy related to primordial recombination radiation (PRR) and primordial y- and μ-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 the CMB dipole does not depend on the particular observation directions and reaches the level of 10-6 for the PRR- and μ-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 the observation directions. For mutually opposite directions, collinear to the CMB dipole axis, the temperature differences due to the PRR- and μ-dipole anisotropy attain values {{Δ }}T≃ 10 {nK} in the considered range. The temperature difference arising from the y-dipole anisotropy may reach values of up to 1 μ {{K}}. The key features of the considered effect are as follow: (i) an observation of the effect does not require absolute calibration; (ii) patches of sky with minimal foreground contamination can be chosen. Future measurements of the CMB dipole distortion thus will provide an alternative method for direct detection of the PRR-, y-, and μ-distortions. The y-distortion dipole may be detectable with PIXIE at a few standard deviations.

  12. Testing of a Single 11 T $Nb_3Sn$ Dipole Coil Using a Dipole Mirror Structure

    SciTech Connect

    Zlobin, Alexander; Andreev, Nicolai; Barzi, Emanuela; Chlachidze, Guram; Kashikhin, Vadim; Nobrega, Alfred; Novitski, Igor; Turrioni, Daniele; Karppinen, Mikko; Smekens, David

    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.

  13. Microwave pump-probe spectroscopy of the dipole-dipole interaction in a cold Rydberg gas

    NASA Astrophysics Data System (ADS)

    Park, Hyunwook; Gallagher, T. F.; Pillet, P.

    2016-05-01

    Microwave pump-probe experiments starting with a cold gas of Rb 34 s atoms confirm that cusped line shapes observed in dipole-dipole broadened microwave transitions are due to atoms which are widely separated and exhibit small dipole-dipole energy shifts. When the experiments are interpreted in terms of a nearest-neighbor model, they demonstrate that it is possible to select pairs of atoms based on their separation and orientation.

  14. Dynamical coupling of pygmy and giant resonances in relativistic Coulomb excitation

    NASA Astrophysics Data System (ADS)

    Brady, N. S.; Aumann, T.; Bertulani, C. A.; Thomas, J. O.

    2016-06-01

    We study the Coulomb excitation of pygmy dipole resonances (PDR) in heavy ion reactions at 100 MeV/nucleon and above. The reactions 68Ni +197Au and 68Ni +208Pb are taken as practical examples. Our goal is to address the question of the influence of giant resonances on the PDR as the dynamics of the collision evolves. We show that the coupling to the giant resonances affects considerably the excitation probabilities of the PDR, a result that indicates the need of an improved theoretical treatment of the reaction dynamics at these bombarding energies.

  15. Stripline dipole with dielectric covering

    NASA Astrophysics Data System (ADS)

    Wang, J.; Hansen, V.

    The use of stripline antennas has greatly increased during the last ten years. In connection with an employment of the antennas, it is often necessary to provide an additional dielectric covering layer to protect the antenna against atmospheric conditions. Water or ice layers can also be described as dielectric layers. The present investigation is concerned with the effect of such additional layers on the radiation characteristics of stripline dipoles. A description is presented of a procedure for the calculation of all important antenna characteristics, taking into account current distribution, input impedance, radiation characteristics, the excitation of surface waves, and aspects of coupling. With the aid of a number of examples it is shown that even a thin covering layer can have a pronounced effect. Such layers can, therefore, also be employed to modify the antenna radiation characteristics to improve their suitability for a given application.

  16. Dipole Relaxation in an Electric Field.

    ERIC Educational Resources Information Center

    Neumann, Richard M.

    1980-01-01

    Derives an expression for the orientational entropy of a rigid rod (electric dipole) from Boltzmann's equation. Subsequent application of Newton's second law of motion produces Debye's classical expression for the relaxation of an electric dipole in a viscous medium. (Author/GS)

  17. Approximate analysis of electromagnetically coupled microstrip dipoles

    NASA Astrophysics Data System (ADS)

    Kominami, M.; Yakuwa, N.; Kusaka, H.

    1990-10-01

    A new dynamic analysis model for analyzing electromagnetically coupled (EMC) microstrip dipoles is proposed. The formulation is based on an approximate treatment of the dielectric substrate. Calculations of the equivalent impedance of two different EMC dipole configurations are compared with measured data and full-wave solutions. The agreement is very good.

  18. How to Introduce the Magnetic Dipole Moment

    ERIC Educational Resources Information Center

    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…

  19. Electric dipoles on the Bloch sphere

    NASA Astrophysics Data System (ADS)

    Vutha, Amar C.

    2015-03-01

    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 and molecular physics.

  20. Final Report: Levitated Dipole Experiment

    SciTech Connect

    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 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.

  1. Dipole response in 208Pb within a self-consistent multiphonon approach

    NASA Astrophysics Data System (ADS)

    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.

  2. A giant vesical calculus.

    PubMed

    Rahman, M; Uddin, A; Das, G C; Akanda, N I

    2007-07-01

    Massive or giant vesical calculus is a rare entity in the recent urological practice. Males are affected more than the females. Vesical calculi are usually secondary to bladder outlet obstruction. These patients present with recurrent urinary tract infection, haematuria or with retention of urine. We report a young male patient who presented with defaecatory problems along with other urinary symptoms. The patient having an average built, non diabetic but hypertensive. The stone could be palpated by physical examination. His urea levels were within normal limits but urine examination shows infection. USG reveals bilateral hydronephrosis with multiple stones in both kidneys along with a giant vesical calculus. After controlling urinary infection and hypertention he underwent an open cystolithotomy. During operation digital rectal help was needed to remove the stone as it was adherent with bladder mucosa. Post operative period was uneventful. His urinary output was quite normal and had no defaecatory problems. Patient left the hospital 10 days after operation. PMID:17917633

  3. High-field dipoles for future accelerators

    SciTech Connect

    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.

  4. Giant thymic carcinoid.

    PubMed

    John, L C; Hornick, P; Lang, S; Wallis, J; Edmondson, S J

    1991-05-01

    Thymic carcinoid is a rare tumour. It may present with ectopic endocrine secretion or with symptoms of compression as a result of its size. A case is reported which presented with symptoms of compression where the size of the tumour was uniquely large such as to warrant the term giant thymic carcinoid. The typical histological features are described, together with its possible origin and its likely prognosis. PMID:1852667

  5. Giant dedifferentiated retroperitoneal liposarcoma.

    PubMed

    Dominguez, Elias; Lopez de Cenarruzabeitia, Iñigo; Martinez, Manuel; Rueda, J C; Lede, A; Barreiro, Erica; Diz, Susana

    2008-01-01

    Liposarcoma tumors only represent 0.1% of all cancers, but they are the more common of retroperitoneal sarcomas. It has a great tendency for local recurrence, mainly the dedifferentiated variety, but its complete resection can provide a 5-year survival of 70%. In this report, we present a case of a giant dedifferentiated retroperitoneal liposarcoma that did not affect any neighboring organ and that was successfully treated by means of complete surgical resection. PMID:19731863

  6. Giant rodlike reversed micelles

    SciTech Connect

    Yu, Z.J.; Neuman, R.D. )

    1994-05-04

    Herein we report that sodium bis(2-ethylhexyl)phosphate, which is similar in structure to the classical surfactant sodium bis(2-ethylhexyl)sulfosuccinate (AOT), forms very large rodlike reversed micelles and that their size can be even much larger if water is removed from the apolar solution. We further suggest that long-range electrostatic interactions are the primary driving force for the formation of giant reversed micelles. 19 refs., 3 figs.

  7. Giant cell arteritis

    PubMed Central

    Calvo-Romero, J

    2003-01-01

    Giant cell arteritis (GCA), temporal arteritis or Horton's arteritis, is a systemic vasculitis which involves large and medium sized vessels, especially the extracranial branches of the carotid arteries, in persons usually older than 50 years. Permanent visual loss, ischaemic strokes, and thoracic and abdominal aortic aneurysms are feared complications of GCA. The treatment consists of high dose steroids. Mortality, with a correct treatment, in patients with GCA seems to be similar that of controls. PMID:13679546

  8. Red giants seismology

    NASA Astrophysics Data System (ADS)

    Mosser, B.; Samadi, R.; Belkacem, K.

    2013-11-01

    The space-borne missions CoRoT and Kepler are indiscreet. With their asteroseismic programs, they tell us what is hidden deep inside the stars. Waves excited just below the stellar surface travel throughout the stellar interior and unveil many secrets: how old is the star, how big, how massive, how fast (or slow) its core is dancing. This paper intends to paparazze the red giants according to the seismic pictures we have from their interiors.

  9. Giant radio pulses

    NASA Astrophysics Data System (ADS)

    Kondratiev, Vladislav

    Rotation-powered radio pulsars exhibit a remarkably diverse spectrum of variability with characteristic time scales from days and even years (intermittent pulsars) to minutes-seconds (nulling) and (sub-)microseconds. The latter time scales are associated with the phenomenon of giant pulses (GPs) and micropulses. The story of GPs started in 1968, when Staelin and Reifenstein discovered the Crab pulsar through its spectacularly bright radio pulses. To date, only seven pulsars out of more than 2200 are known to show GP emission, namely the pulsars B0531+21, B1937+21, B0540-69, B1821-24, B1957+20, J0218+4232, and B1820-30A. Giant pulses are characterized by large energies (more than ten times of the energy of the average pulse), short durations, power-law energy distribution, specific rotational phase of occurrence, high degree of polarization, and accompanying high-energy radiation. Large energies of GPs and coincidence of their phase of occurrence with peaks of high-energy profiles hint at the same mechanism of radio GP and high-energy emission. The correlation of Crab pulsar GPs with optical, X-ray and gamma-ray photons was studied for the past 20 years, with only radio/optical link confirmed so far. In my talk I will present the summary of the observational evidence of radio GPs and give an overview of theoretical advances on giant-pulse emission mechanism.

  10. Asteroseismology can reveal strong internal magnetic fields in red giant stars.

    PubMed

    Fuller, Jim; Cantiello, Matteo; Stello, Dennis; Garcia, Rafael A; Bildsten, Lars

    2015-10-23

    Internal stellar magnetic fields are inaccessible to direct observations, and little is known about their amplitude, geometry, and evolution. We demonstrate that strong magnetic fields in the cores of red giant stars can be identified with asteroseismology. The fields can manifest themselves via depressed dipole stellar oscillation modes, arising from a magnetic greenhouse effect that scatters and traps oscillation-mode energy within the core of the star. The Kepler satellite has observed a few dozen red giants with depressed dipole modes, which we interpret as stars with strongly magnetized cores. We find that field strengths larger than ~10(5) gauss may produce the observed depression, and in one case we infer a minimum core field strength of ≈10(7) gauss. PMID:26494754

  11. Unusual Giant Prostatic Urethral Calculus

    PubMed Central

    Bello, A.; Maitama, H. Y.; Mbibu, N. H.; Kalayi, G. D.; Ahmed, A.

    2010-01-01

    Giant vesico-prostatic urethral calculus is uncommon. Urethral stones rarely form primarily in the urethra, and they are usually associated with urethral strictures, posterior urethral valve or diverticula. We report a case of a 32-year-old man with giant vesico-prostatic (collar-stud) urethral stone presenting with sepsis and bladder outlet obstruction. The clinical presentation, management, and outcome of the giant prostatic urethral calculus are reviewed. PMID:22091328

  12. Low-lying dipole response in the stable {sup 40,48}Ca nuclei with the second random-phase approximation

    SciTech Connect

    Gambacurta, D.; Catara, F.

    2011-09-15

    Low-energy dipole excitations are analyzed for the stable isotopes {sup 40}Ca and {sup 48}Ca in the framework of the Skyrme-second random-phase approximation. The corresponding random-phase approximation calculations provide a negligible strength distribution for both nuclei in the energy region from 5 to 10 MeV. The inclusion and the coupling of 2 particle-2 hole configurations in the second random-phase approximation lead to an appreciable dipole response at low energies for the neutron-rich nucleus {sup 48}Ca. The presence of a neutron skin in the nucleus {sup 48}Ca would suggest the interpretation of the low-lying response in terms of a pygmy excitation. The composition of the excitation modes (content of 1 particle-1 hole and 2 particle-2 hole configurations), their transition densities and their collectivity (number and coherence of the different contributions) are analyzed. This analysis indicates that, in general, these excitations cannot be clearly interpreted in terms of oscillations of the neutron skin against the core with the exception of the peak with the largest B(E1) value, which is located at 9.09 MeV. For this peak the neutron transition density dominates and the neutron and proton transition densities oscillate out of phase in the internal part of the nucleus leading to a strong mixing of isoscalar and isovector components. Therefore, this state shows some features usually associated to pygmy resonances.

  13. Final Report: Levitated Dipole Experiment

    SciTech Connect

    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

  14. The ROSAT X-ray background dipole

    NASA Astrophysics Data System (ADS)

    Plionis, M.; Georgantopoulos, I.

    1999-06-01

    We estimate the dipole of the diffuse 1.5-keV X-ray background from the ROSAT all-sky survey map of Snowden et al. We first subtract the diffuse Galactic emission by fitting an exponential scaleheight, finite-radius, disc model to the data. We further exclude regions of low galactic latitudes, of local X-ray emission (e.g. the North Polar Spur) and model them using two different methods. We find that the ROSAT X-ray background dipole points towards (l,b) ~ (288 deg 25 deg) +/- 19 deg in consistency with the cosmic microwave background (within ~ 30 deg) its direction is also in good agreement with the HEAO-1 X-ray dipole at harder energies. The normalized amplitude of the ROSAT XRB dipole is ~ 1.7 per cent. Subtracting from the ROSAT map the expected X-ray background dipole resulting from the reflex motion of the observer with respect to the cosmic rest frame (Compton-Getting effect) we find the large-scale dipole of the X-ray emitting extragalactic sources having an amplitude D_LSS ~ 0.9 D_XRB, in general agreement with the predictions of Lahav et al. We finally estimate that the Virgo cluster is responsible for ~ 20 per cent of the total measured XRB dipole amplitude.

  15. Constraints on exotic dipole-dipole couplings between electrons at the micron scale

    NASA Astrophysics Data System (ADS)

    Kotler, Shlomi; Ozeri, Roee; Jackson Kimball, Derek

    2015-05-01

    Until recently, the magnetic dipole-dipole coupling between electrons had not been directly observed experimentally. This is because at the atomic scale dipole-dipole coupling is dominated by the exchange interaction and at larger distances the dipole-dipole coupling is overwhelmed by ambient magnetic field noise. In spite of these challenges, the magnetic dipole-dipole interaction between two electron spins separated by 2.4 microns was recently measured using the valence electrons of trapped Strontium ions [S. Kotler, N. Akerman, N. Navon, Y. Glickman, and R. Ozeri, Nature 510, 376 (2014)]. We have used this measurement to directly constrain exotic dipole-dipole interactions between electrons at the micron scale. For light bosons (mass 0.1 eV), we find that coupling constants describing pseudoscalar and axial-vector mediated interactions must be | gPegPe/4 πℏc | <= 1 . 5 × 10-3 and | gAegAe/4 πℏc | <= 1 . 2 × 10-17 , respectively, at the 90% confidence level. These bounds significantly improve on previous constraints in this mass range: for example, the constraints on axial-vector interactions are six orders of magnitude stronger than electron-positron constraints based on positronium spectroscopy. Supported by the National Science Foundation, I-Core: the Israeli excellence center, and the European Research Council.

  16. Hexasubstituted Benzenes with Ultrastrong Dipole Moments.

    PubMed

    Wudarczyk, Jakob; Papamokos, George; Margaritis, Vasilis; Schollmeyer, Dieter; Hinkel, Felix; Baumgarten, Martin; Floudas, George; Müllen, Klaus

    2016-02-24

    Hexasubstituted benzenes have been synthesized with the highest known dipole moments, as determined by dielectric spectroscopy and DFT methods. Based on the preparation of 4,5-diamino-3,6-dibromophthalonitrile, combined with a novel method to synthesize dihydrobenzimidazoles, these benzene derivatives have dipole moments in excess of 10 debye. Such dipole moments are desirable in ferroelectrics, nonlinear optics, and in organic photovoltaics. Structure determination was achieved through single-crystal X-ray crystallography, and the optical properties were determined by UV/Vis absorption and fluorescence spectroscopy. PMID:26836590

  17. The field of a screened magnetic dipole

    NASA Technical Reports Server (NTRS)

    Greene, J. M.; Miller, R. L.

    1994-01-01

    The purpose of this note is to quantitatively study the asymptotic behavior of the dipole magnetic field in the tail region of a paraboloidal or cylindrical model of the magnetosphere, assuming the complete screening of the internal field by magnetopause currents. This screening assumption is equivalent to imposing the boundary condition that the normal component of the magnetic field is zero at the magnetopause. With this boundary condition, the screened dipole field falls off exponentially with distance down the tail, in sharp constrast to the bare dipole field. Analytic expressions for a cylindrical and paraboloidal magnetopause are given.

  18. Axion induced oscillating electric dipole moments

    SciTech Connect

    Hill, Christopher T.

    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 ma 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.

  19. Quadrupole radiation from terahertz dipole antennas.

    PubMed

    Rudd, J V; Johnson, J L; Mittleman, D M

    2000-10-15

    We report what is to our knowledge the first detailed investigation of the polarization state of radiation from lens-coupled terahertz dipole antennas. The radiation exhibits a weak but measurable component that is polarized orthogonally to the orientation of the emitter dipole. The angular radiation pattern of this cross-polarized emission reveals that it is quadrupolar, rather than dipolar, in nature. One can understand this result by taking into account the photocurrent flowing in the strip lines that feed the dipole antenna. A Fresnel-Kirchhoff scalar diffraction calculation is used for calculating the frequency-dependent angular distribution of the radiation pattern, providing satisfactory agreement with the measurements. PMID:18066277

  20. Magnetic dipole discharges. III. Instabilities

    SciTech Connect

    Stenzel, R. L.; Urrutia, J. M.; Ionita, C.; Schrittwieser, R.

    2013-08-15

    Instabilities in a cross-field discharge around a permanent magnet have been investigated. The permanent magnet serves as a cold cathode and the chamber wall as an anode. The magnet is biased strongly negative and emits secondary electrons due to impact of energetic ions. The electrons outside the sheath are confined by the strong dipolar magnetic field and by the ion-rich sheath surrounding the magnet. The electron energy peaks in the equatorial plane where most ionization occurs and the ions are trapped in a negative potential well. The discharge mechanism is the same as that of cylindrical and planar magnetrons, but here extended to a 3-D cathode geometry using a single dipole magnet. While the basic properties of the discharge are presented in a companion paper, the present focus is on various observed instabilities. The first is an ion sheath instability which oscillates the plasma potential outside the sheath below the ion plasma frequency. It arises in ion-rich sheaths with low electron supply, which is the case for low secondary emission yields. Sheath oscillations modulate the discharge current creating oscillating magnetic fields. The second instability is current-driven ion sound turbulence due to counter-streaming electrons and ions. The fluctuations have a broad spectrum and short correlation lengths in all directions. The third type of fluctuations is spiky potential and current oscillations in high density discharges. These appear to be due to unstable emission properties of the magnetron cathode.

  1. Third Elementary Dipole Moment: Toroidal

    NASA Astrophysics Data System (ADS)

    Cordrey, Vincent; Eshete, Amanuel; Majewski, Walerian

    2015-04-01

    In this paper we study the generally unknown characteristics of toroids, magnets without magnetic poles. Toroids have never seemed interesting enough to be studied for their physical features in labs due to the fact that they have no magnetic fields on the outside, but rather a very strong magnetic field trapped inside. Toroidal solenoids or magnets (rings magnetized circumferentially) interact with the external magnetic field only through its curl, which can be created either by an electric current, or by a time-dependent electric flux. We confirmed a theoretical prediction, that a toroid would not interact with the curl-less magnetic field of a current-carrying wire running outside of the torus's hole. We used our toroids as magnetic curlmeters, measuring the torque on the toroid, when the current-carrying wire runs through the toroid. From this torque we found the toroidal dipole moment. We are experimenting on detecting the escape of the inner magnetic field of the toroid outside of it, when magnetic toroid rotates or when electric toroid is driven by AC voltage. We also will discuss toroidal (or anapole) moments of fundamental particles, nuclei and atoms, and toroids' applications in metamaterials.

  2. Giant Coulomb blockade magnetoresistance

    SciTech Connect

    Zhang, Xiaoguang; Wen, Z. C.; Wei, H. X.; Han, Prof. X. F.

    2010-01-01

    We show that the Coulomb blockade voltage can be made to depend strongly on the electron spin in a thin magnetic granular layer inserted in the middle of an insulating layer of a tunnel junction. This strong spin dependence is predicted from the spin-dependent inter-granular conductance through any of the following effects within the granular layer, giant magnetoresistance (GMR), tunneling magnetoresistance (TMR), colossal magnetoresistance (CMR), or GMR through a polymer spacer. The resulting Coulomb blockade magnetoresistance (CBMR) ratio can exceed the magnetoresistance ratio of the granular layer itself by orders of magnitude. Unlike other magenetoresistance effects, the CBMR effect does not require magnetic electrodes.

  3. Giant Cardiac Cavernous Hemangioma.

    PubMed

    Unger, Eric; Costic, Joseph; Laub, Glenn

    2015-07-01

    We report the case of an asymptomatic giant cardiac cavernous hemangioma in a 71-year-old man. The intracardiac mass was discovered incidentally during surveillance for his prostate cancer; however, the patient initially declined intervention. On presentation to our institution 7 years later, the lesion had enlarged significantly, and the patient consented to excision. At surgery, an 8 × 6.5 × 4.8 cm intracardiac mass located on the inferior heart border was excised with an intact capsule through a median sternotomy approach. The patient had an uneventful postoperative course. We discuss the diagnostic workup, treatment, and characteristics of this rare cardiac tumor. PMID:26140782

  4. Study of atomic dipole-dipole interactions via measurement of atom-pair kinetics

    NASA Astrophysics Data System (ADS)

    Thaicharoen, Nithiwadee; Gonçalves, Luís Felipe; Raithel, Georg

    2016-05-01

    We observe atom-pair kinetics due to binary dipolar forces by direct imaging of the center-of-mass positions of the individual Rydberg atoms and pair-correlation analysis. To prepare a highly dipolar quantum state, Rydberg-atom ensembles are switched from a weakly- into a strongly-interacting regime via adiabatic state transformation. The transformed atoms exhibit a large permanent electric dipole moment that is locked to the direction of an applied electric field. The resultant electric dipole-dipole forces reveal dumbbell-shaped pair correlation images that demonstrate the anisotropy of the binary dipolar force. The dipole-dipole interaction coefficient C3, derived from the time dependence of the images, agrees with the value calculated from the known permanent electric-dipole moment of the atoms. The observations also show the dynamics reminiscent of disorder-induced heating in strongly coupled particle systems.

  5. Dipole-fiber systems: radiation field patterns, effective magnetic dipoles, and induced cavity modes

    NASA Astrophysics Data System (ADS)

    Atakaramians, Shaghik; Miroshnichenko, Andrey E.; Shadrivov, Ilya V.; Monro, Tanya M.; Kivshar, Yuri S.; Afshar, Shahraam V.

    2015-12-01

    We study the radiation patterns produced by a dipole placed at the surface of a nanofiber and oriented perpendicular to it, either along the radial (r-oriented) or azimuthal (Φ-oriented) directions. We find that the dipole induces an effective circular cavity-like leaky mode in the nanofiber. The first radiation peak of the Φ-oriented dipole contributes only to TE radiation modes, while the radiation of the r-oriented dipole is composed of both TE and TM radiation modes, with relative contribution depending on the refractive index of the nanofiber. We reveal that the field pattern of the first resonance of a Φ-oriented dipole is associated with a magnetic dipole mode and strong magnetic response of an optical nanofiber.

  6. The Effect of Dipole-Dipole Interaction on Tripartite Entanglement in Different Cavities

    NASA Astrophysics Data System (ADS)

    Khan, Salman; Jan, Munsif

    2016-03-01

    The effect of dipole-dipole interaction, the initial relative phase and the coupling strength with the cavity on the dynamics of three two level atoms in the good and the bad cavity regime are investigated. It is found that the presence of strong dipole-dipole interaction not only ensures avoiding entanglement sudden death but also retains entanglement for long time. The choice of the phase in the initial state is crucial to the operational regime of the cavity. Under specific conditions, the entanglement can be frozen in time to its initial values through strong dipole-dipole interaction. This trait of tripartite entanglement may prove helpful in engineering multiparticle entanglement for the practical realization of quantum technology.

  7. Microstrip dipoles on electrically thick substrates

    NASA Astrophysics Data System (ADS)

    Jackson, D. R.; Alexopoulos, N. G.

    1986-01-01

    Certain basic radiation properties of microstrip dipoles on electrically thick substrates are investigated, and a comparison is made with the case of dipoles printed on a dielectric half-space. It is concluded that the microstrip dipole radiation properties become sensitive to substrate loss as the substrate thickness increases, with the half-space properties obtained for an adequate amount of loss. Asymptotic formulas for radiated power and efficiency are given for both the thick substrate and half-space problems, showing the behavior with increasing dielectric constant. The method of moments is used to extend the analysis to center-fed strip dipoles, and a method of improving both the efficiency and gain of a printed antenna by using a superstrate layer is discussed.

  8. Tevatron optics measurements using an AC dipole

    SciTech Connect

    Miyamoto, R.; Kopp, S.E.; Jansson, A.; Syphers, M.J.; /Fermilab

    2007-06-01

    The AC dipole is a device to study beam optics of hadron synchrotrons. It can produce sustained large amplitude oscillations with virtually no emittance growth. A vertical AC dipole for the Tevatron is recently implemented and a maximum oscillation amplitude of 2{sigma} (4{sigma}) at 980 GeV (150 GeV) is achieved [1]. When such large oscillations are measured with the BPM system of the Tevatron (20 {micro}m resolution), not only linear but even nonlinear optics can be directly measured. This paper shows how to measure {beta} function using an AC dipole and the result is compared to the other measurement. The paper also shows a test to detect optics changes when small changes are made in the Tevatron. Since an AC dipole is nondestructive, it allows frequent measurements of the optics which is necessary for such an test.

  9. Roles of deformation and neutron excess on the giant monopole resonance in neutron-rich Zr isotopes

    SciTech Connect

    Yoshida, Kenichi

    2010-09-15

    We investigate the roles of deformation on the giant monopole resonance (GMR), particularly the mixing of the giant quadrupole resonance (GQR) and the effects of the neutron excess in the well-deformed nuclei around {sup 110}Zr and in the drip-line nuclei around {sup 140}Zr by means of the deformed quasiparticle-random-phase approximation employing the Skyrme and the local-pairing energy-density functionals. It is found that the isoscalar (IS) GMR has a two-peak structure, the lower peak of which is associated with the mixing between the ISGMR and the K{sup {pi}=}0{sup +} component of the ISGQR. The transition strength of the lower peak of the ISGMR grows as the neutron number increases. In the drip-line nuclei, the neutron excitation is dominant over the proton excitation. We find that for an isovector (IV) excitation the GMR has a four-peak structure due to the mixing of the IS and IV modes as well as the mixing of the K{sup {pi}=}0{sup +} component of the IVGQR. In addition to the GMR, we find that the threshold strength is generated by neutrons only.

  10. Dipole Bands in {sup 196}Hg

    SciTech Connect

    Lawrie, J. J.; Lawrie, E. A.; Newman, R. T.; Sharpey-Schafer, J. F.; Smit, F. D.; Msezane, B.; Benatar, M.; Mabala, G. K.; Mutshena, K. P.; Federke, M.; Mullins, S. M.; Ncapayi, N. J.; Vymers, P.

    2011-10-28

    High spin states in {sup 196}Hg have been populated in the {sup 198}Pt({alpha},6n) reaction at 65 MeV and the level scheme has been extended. A new dipole band has been observed and a previously observed dipole has been confirmed. Excitation energies, spins and parities of these bands were determined from DCO ratio and linear polarization measurements. Possible quasiparticle excitations responsible for these structures are discussed.

  11. Magnetic dipole transitions in the hydrogen molecule

    SciTech Connect

    Pachucki, Krzysztof; Komasa, Jacek

    2011-03-15

    In homonuclear molecules, such as H{sub 2}, the electric dipole transitions are strongly forbidden, and the transitions between rovibrational states are of the electric quadrupole type. We show, however, that magnetic dipole transitions also take place, although they are significantly weaker. We evaluate the probabilities of such transitions between several of the lowest rotational states and compare them with those of the corresponding electric quadrupole transitions.

  12. Magnetic dipole interactions in crystals

    NASA Astrophysics Data System (ADS)

    Johnston, David C.

    2016-01-01

    The influence of magnetic dipole interactions (MDIs) on the magnetic properties of local-moment Heisenberg spin systems is investigated. A general formulation is presented for calculating the eigenvalues λ and eigenvectors μ ̂ of the MDI tensor of the magnetic dipoles in a line (one dimension, 1D), within a circle (2D) or a sphere (3D) of radius r surrounding a given moment μ⃗i for given magnetic propagation vectors k for collinear and coplanar noncollinear magnetic structures on both Bravais and non-Bravais spin lattices. Results are calculated for collinear ordering on 1D chains, 2D square and simple-hexagonal (triangular) Bravais lattices, 2D honeycomb and kagomé non-Bravais lattices, and 3D cubic Bravais lattices. The λ and μ ̂ values are compared with previously reported results. Calculations for collinear ordering on 3D simple tetragonal, body-centered tetragonal, and stacked triangular and honeycomb lattices are presented for c /a ratios from 0.5 to 3 in both graphical and tabular form to facilitate comparison of experimentally determined easy axes of ordering on these Bravais lattices with the predictions for MDIs. Comparisons with the easy axes measured for several illustrative collinear antiferromagnets (AFMs) are given. The calculations are extended to the cycloidal noncollinear 120∘ AFM ordering on the triangular lattice where λ is found to be the same as for collinear AFM ordering with the same k. The angular orientation of the ordered moments in the noncollinear coplanar AFM structure of GdB4 with a distorted stacked 3D Shastry-Sutherland spin-lattice geometry is calculated and found to be in disagreement with experimental observations, indicating the presence of another source of anisotropy. Similar calculations for the undistorted 2D and stacked 3D Shastry-Sutherland lattices are reported. The thermodynamics of dipolar magnets are calculated using the Weiss molecular field theory for quantum spins, including the magnetic transition

  13. Magnetic dipole interactions in crystals

    DOE PAGESBeta

    Johnston, David

    2016-01-13

    The influence of magnetic dipole interactions (MDIs) on the magnetic properties of local-moment Heisenberg spin systems is investigated. A general formulation is presented for calculating the eigenvalues λ and eigenvectors μ ˆ of the MDI tensor of the magnetic dipoles in a line (one dimension, 1D), within a circle (2D) or a sphere (3D) of radius r surrounding a given moment μ → i for given magnetic propagation vectors k for collinear and coplanar noncollinear magnetic structures on both Bravais and non-Bravais spin lattices. Results are calculated for collinear ordering on 1D chains, 2D square and simple-hexagonal (triangular) Bravais lattices,more » 2D honeycomb and kagomé non-Bravais lattices, and 3D cubic Bravais lattices. The λ and μ ˆ values are compared with previously reported results. Calculations for collinear ordering on 3D simple tetragonal, body-centered tetragonal, and stacked triangular and honeycomb lattices are presented for c/a ratios from 0.5 to 3 in both graphical and tabular form to facilitate comparison of experimentally determined easy axes of ordering on these Bravais lattices with the predictions for MDIs. Comparisons with the easy axes measured for several illustrative collinear antiferromagnets (AFMs) are given. The calculations are extended to the cycloidal noncollinear 120 ° AFM ordering on the triangular lattice where λ is found to be the same as for collinear AFM ordering with the same k. The angular orientation of the ordered moments in the noncollinear coplanar AFM structure of GdB 4 with a distorted stacked 3D Shastry-Sutherland spin-lattice geometry is calculated and found to be in disagreement with experimental observations, indicating the presence of another source of anisotropy. Similar calculations for the undistorted 2D and stacked 3D Shastry-Sutherland lattices are reported. The thermodynamics of dipolar magnets are calculated using the Weiss molecular field theory for quantum spins, including the magnetic

  14. Controlling dipole-dipole frequency shifts in a lattice-based optical atomic clock

    SciTech Connect

    Chang, D.E.; Lukin, M.D.; Ye Jun

    2004-02-01

    Motivated by the ideas of using cold alkaline-earth atoms trapped in an optical lattice for realization of optical atomic clocks, we investigate theoretically the perturbative effects of atom-atom interactions on a clock transition frequency. These interactions are mediated by the dipole fields associated with the optically excited atoms. We predict resonancelike features in the frequency shifts when constructive interference among atomic dipoles occur. We theoretically demonstrate that by fine tuning the coherent dipole-dipole couplings in appropriately designed lattice geometries, the undesirable frequency shifts can be greatly suppressed.

  15. Critical properties of entanglement in the Dicke model with the dipole-dipole interactions

    NASA Astrophysics Data System (ADS)

    Nie, J.; Huang, X. L.; Yi, X. X.

    2009-04-01

    In this paper, we investigate two aspects of entanglement properties of the ground state for the Dicke model with the dipole-dipole interaction between the atoms in the thermodynamic limit, and observe how they are affected by the quantum phase transition. The appearance of dipole-dipole interactions between the atoms does not change the maximum atom-field entanglement at the critical point, while it changes the maximum atom-atom entanglement at the critical point, and has an important influence on the atom-atom entanglement behavior.

  16. Rheology of giant micelles

    NASA Astrophysics Data System (ADS)

    Cates, M. E.; Fielding, S. M.

    2006-12-01

    Giant micelles are elongated, polymer-like objects created by the self-assembly of amphiphilic molecules (such as detergents) in solution. Giant micelles are typically flexible, and can become highly entangled even at modest concentrations. The resulting viscoelastic solutions show fascinating flow behaviour (rheology) which we address theoretically in this article at two levels. First, we summarize advances in understanding linear viscoelastic spectra and steady-state nonlinear flows, based on microscopic constitutive models that combine the physics of polymer entanglement with the reversible kinetics of self-assembly. Such models were first introduced two decades ago, and since then have been shown to explain robustly several distinctive features of the rheology in the strongly entangled regime, including extreme shear thinning. We then turn to more complex rheological phenomena, particularly involving spatial heterogeneity, spontaneous oscillation, instability and chaos. Recent understanding of these complex flows is based largely on grossly simplified models which capture in outline just a few pertinent microscopic features, such as coupling between stresses and other order parameters such as concentration. The role of ‘structural memory’ (the dependence of structural parameters such as the micellar length distribution on the flow history) in explaining these highly nonlinear phenomena is addressed. Structural memory also plays an intriguing role in the little-understood shear thickening regime, which occurs in a concentration regime close to but below the onset of strong entanglement, and which is marked by a shear-induced transformation from an inviscid to a gelatinous state.

  17. Giant solitary trichoepithelioma

    PubMed Central

    Teli, Bhavuray; Thrishuli, P. B.; Santhosh, R.; Amar, D. N.; Rajpurohit, Shravan

    2015-01-01

    Adnexal tumors like giant solitary trichoepitheliomas are uncommon to most of us to permit a ready familiarity with them. Information regarding the genesis, clinical profile, behavior, and management options for this tumor is limited. There are 18 cases reported in the world literature till date. This review attempts to provide insight to this rare tumor. Our search included indexed literature from Pubmed, Directory of Open Access Journals, Health Inter Network Access to Research Initiative and Google databases in addition to standard dermatology texts. Giant solitary trichoepithelioma is a rare trichogenic tumor with potential for local recurrence. It has predilection for the older age, but may present at any age including at birth. It has close resemblance to basal cell carcinoma and other skin adnexal tumors - clinically, cytologically, and histologically. CD10, CD 34, PHLDA1 but not p75NTR are useful adjunct markers. Surgical excision is the standard treatment. Recurrence and possible transformation into BCC cautions follow up at regular intervals. PMID:25839021

  18. Giant solitary trichoepithelioma.

    PubMed

    Teli, Bhavuray; Thrishuli, P B; Santhosh, R; Amar, D N; Rajpurohit, Shravan

    2015-01-01

    Adnexal tumors like giant solitary trichoepitheliomas are uncommon to most of us to permit a ready familiarity with them. Information regarding the genesis, clinical profile, behavior, and management options for this tumor is limited. There are 18 cases reported in the world literature till date. This review attempts to provide insight to this rare tumor. Our search included indexed literature from Pubmed, Directory of Open Access Journals, Health Inter Network Access to Research Initiative and Google databases in addition to standard dermatology texts. Giant solitary trichoepithelioma is a rare trichogenic tumor with potential for local recurrence. It has predilection for the older age, but may present at any age including at birth. It has close resemblance to basal cell carcinoma and other skin adnexal tumors - clinically, cytologically, and histologically. CD10, CD 34, PHLDA1 but not p75NTR are useful adjunct markers. Surgical excision is the standard treatment. Recurrence and possible transformation into BCC cautions follow up at regular intervals. PMID:25839021

  19. Giant papillary conjunctivitis.

    PubMed Central

    Donshik, P C

    1994-01-01

    Giant papillary conjunctivitis is a syndrome found frequently as a complication of contact lenses. Many variables can affect the onset and severity of the presenting signs and symptoms. Rigid gas permeable contact lenses appear to result in less severe signs and symptoms, with a longer time before the development of giant papillary conjunctivitis. Nonionic, low-water-content soft contact lenses tend to produce less severe signs and symptoms than ionic, low-water-content soft contact lenses. Enzymatic treatment appears to lessen the severity of signs and symptoms. The association of an allergy appears to play a role in the onset of the severity of the signs and symptoms but does not appear to affect the final ability of the individual to wear contact lenses. Using multiple treatment options, such as changing the polymer to a glyceryl methyl methacrylate or a rigid lens, or utilizing a soft lens on a frequent-replacement basis, can result in a success rate of over 90%. In individuals who still have a return of symptoms, the use of topical mast cell stabilizers or a nonsteroidal anti-inflammatory drug as an adjunctive therapy offers the added possibility of keeping these patients in contact lenses. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 11 A FIGURE 11 B FIGURE 11 C FIGURE 11 D PMID:7886881

  20. electric dipole superconductor in bilayer exciton system

    NASA Astrophysics Data System (ADS)

    Sun, Qing-Feng; Jiang, Qing-Dong; Bao, Zhi-Qiang; Xie, X. C.

    Recently, it was reported that the bilayer exciton systems could exhibit many new phenomena, including the large bilayer counterflow conductivity, the Coulomb drag, etc. These phenomena imply the formation of exciton condensate superfluid state. On the other hand, it is now well known that the superconductor is the condensate superfluid state of the Cooper pairs, which can be viewed as electric monopoles. In other words, the superconductor state is the electric monopole condensate superfluid state. Thus, one may wonder whether there exists electric dipole superfluid state. In this talk, we point out that the exciton in a bilayer system can be considered as a charge neutral electric dipole. And we derive the London-type and Ginzburg-Landau-type equations of electric dipole superconductivity. From these equations, we discover the Meissner-type effect (against spatial variation of magnetic fields), and the dipole current Josephson effect. The frequency in the AC Josephson effect of the dipole current is equal to that in the normal (monopole) superconductor. These results can provide direct evidence for the formation of exciton superfluid state in the bilayer systems and pave new ways to obtain the electric dipole current. We gratefully acknowledge the financial support by NBRP of China (2012CB921303 and 2015CB921102) and NSF-China under Grants Nos. 11274364 and 11574007.

  1. Dipole-moment-driven cooperative supramolecular polymerization.

    PubMed

    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. PMID:25756951

  2. A Dipole Assisted IEC Neutron Source

    SciTech Connect

    Prajakti Joshi Shrestha

    2005-11-28

    A potential opportunity to enhance Inertial Electrostatic Confinement (IEC) fusion exists by augmenting it with a magnetic dipole configuration. The theory is that the dipole fields will enhance the plasma density in the center region of the IEC and the combined IEC and dipole confinement properties will reduce plasma losses. To demonstrate that a hybrid Dipole-IEC configuration can provide an improved neutron source vs. a stand alone IEC, a first model Dipole-IEC experiment was benchmarked against a reference IEC. A triple Langmuir probe was used to find the electron temperature and density. It was found that the magnetic field increases the electron density by a factor of 16, the electron temperature decreases in the presence of a magnetic field, the discharge voltage decreases in the presence of a magnetic field, the potential of the dipole strongly influences the densities obtained in the center. The experimental set-up and plasma diagnostics are discussed in detail, as well as the results, and the developmental issues.

  3. Allometry indicates giant eyes of giant squid are not exceptional

    PubMed Central

    2013-01-01

    Background The eyes of giant and colossal squid are among the largest eyes in the history of life. It was recently proposed that sperm whale predation is the main driver of eye size evolution in giant squid, on the basis of an optical model that suggested optimal performance in detecting large luminous visual targets such as whales in the deep sea. However, it is poorly understood how the eye size of giant and colossal squid compares to that of other aquatic organisms when scaling effects are considered. Results We performed a large-scale comparative study that included 87 squid species and 237 species of acanthomorph fish. While squid have larger eyes than most acanthomorphs, a comparison of relative eye size among squid suggests that giant and colossal squid do not have unusually large eyes. After revising constants used in a previous model we found that large eyes perform equally well in detecting point targets and large luminous targets in the deep sea. Conclusions The eyes of giant and colossal squid do not appear exceptionally large when allometric effects are considered. It is probable that the giant eyes of giant squid result from a phylogenetically conserved developmental pattern manifested in very large animals. Whatever the cause of large eyes, they appear to have several advantages for vision in the reduced light of the deep mesopelagic zone. PMID:23418818

  4. Damping of giant resonances in hot nuclei

    SciTech Connect

    Smerzi, A.; Bonasera, A.; DiToro, M. )

    1991-10-01

    The effect of one- and two-body dissipation on the damping of giant dipole resonances (GDR's) is studied in a semiclassical approach solving a Vlasov equation with a collision relaxation time. The latter is microscopically evaluated from the equilibration of a distorted momentum distribution in a kinetic approach. Temperature effects are introduced in the initial distribution function and in Pauli blocking rearrangement in the path to equilibration. Particle emission is also computed in the same microscopic picture. Without free parameters a good agreement with data is obtained for GDR's on the ground state. For collective vibration built on excited states we get a dramatic increase of the widths due to the enhancement of nucleon-nucleon ({ital NN}) collisions. The saturation observed in some experiments is explained as due to the competition of particle evaporation which cools down the system. The transition to first-sound modes is ruled out for the persistence of long-nucleon mean free paths at relatively high temperatures.

  5. Giant magnetostrictive composites

    NASA Astrophysics Data System (ADS)

    Duenas, Terrisa Ann

    The limitation of magnetostrictive composites has been in their low magnetostrictive response when compared to their monolithic counterparts. In this dissertation research is presented describing the methods and analysis used to create a giant magnetostrictive composite (GMC) producing giant strains at low fields, exhibiting magnetization ``jumping'' and the ΔE effect. This composite combines the giant magnetostrictive material, Terfenol-D (Tb0.3Dy0.7Fe2) in particle form, with a nonmetallic binder and is capable of producing strains (at room temperature) exceeding 1000 ppm at a nominal field of 1.5 kOe mechanically unloaded and 1200 ppm at 8 MPa preload (2.5 kOe). Several studies leading to the high response of this composite are presented. A connectivity study shows that a [1-3] connected composite produces 50% more strain than a [0-3] composite. A resin study indicates that the lower the viscosity of the resin, the greater the magnetostrictive response; this is attributed to the removal of voids during degassing. A void study correlates the increase in voids to the decrease in strain response. A model is used to correlate analysis with experimental results within 10% accuracy and shows that an optimal volume fraction exists based on the properties of the binder. Using a Polyscience Spurr low- viscosity (60 cps) binder this volume fraction is nominally 20%; this optimum is attributed to the balance of epoxy contracting on the particle (built-in preload) and the actuation delivered by the magnetostrictive material. In addition to the connectivity, resin, void, and volume-fraction study, particle size and gradation studies are presented. Widely dispersed (<106, <212, <300 μm), narrowly dispersed (<45, (90-106), (275-300) μm), and an optimized bimodal (18.7% of (45-90) μm with 81.3% of (250-300) μm) particle distributions are studied. Results show that the larger the particle size, the higher the magnetostrictive response; this is attributed to the reduction of

  6. A basic program to transform continuous polar dipole-dipole resistivity soundings to half-Schlumberger soundings

    USGS Publications Warehouse

    Zerilli, A.; Bisdorf, R.J.

    1990-01-01

    An interactive HP 9845B BASIC program transforms continuous polar dipole-dipole resistivity soundings to half-Schlumberger soundings. The program features graphic presentation of the field dipole-dipole data as well as the transformed half-Schlumberger data. An example of the transformation and its effectiveness in smoothing "high-frequency" noise is given. ?? 1990.

  7. Dipole effects in a cold Rydberg gas

    NASA Astrophysics Data System (ADS)

    Han, Jianing

    2009-12-01

    This dissertation is a continuing study of the dipole effects between cold Rydberg atoms in a MOT (Magneto Optical Trap). The dipole-dipole interaction is commonly used to explain the plasma forming process and dipole blockade effects. However, no direct measurements have been made for such interaction. This dissertation is designed to directly measure this interaction and study the effects induced by the dipole interaction. To achieve this, a few experiments were carried out. First, a millimeter wave spectroscopy experiment was performed to determine quantum defects of higher angular momentum f and g states, which then allows us to accurately identify these states. Moreover, the higher angular momentum states play an important role in the plasma forming process. The next experiment examined the oscilloscope trace collected through field ionization pulses on which all our experiments are based, which leads to the conclusion that the side peaks other than the main peak can be due to the field ionization pulse sweeping through the resonances. Based on the knowledge of identifying states obtained from these two experiments, a third experiment was carried out to understand the interactions between cold Rydberg atoms. It was found that the second order dipole-dipole interaction, the van der Waals interaction, commonly exists between the atoms in our atomic sample, and when we excite the atoms from the ns to (n + 1)s states using a narrow band microwave pulse, an asymmetric broadening, which is attributed to the nsns to ns(n + 1) s molecular state transition, was observed. Furthermore, the van der Waals long range molecule is studied, which provides another way to study the two-body to multi-body transition.

  8. Giant magnetofossils and hyperthermal events

    NASA Astrophysics Data System (ADS)

    Chang, Liao; Roberts, Andrew P.; Williams, Wyn; Fitz Gerald, John D.; Larrasoaña, Juan C.; Jovane, Luigi; Muxworthy, Adrian R.

    2012-10-01

    Magnetotactic bacteria biomineralize magnetic minerals with precisely controlled size, morphology, and stoichiometry. These cosmopolitan bacteria are widely observed in aquatic environments. If preserved after burial, the inorganic remains of magnetotactic bacteria act as magnetofossils that record ancient geomagnetic field variations. They also have potential to provide paleoenvironmental information. In contrast to conventional magnetofossils, giant magnetofossils (most likely produced by eukaryotic organisms) have only been reported once before from Paleocene-Eocene Thermal Maximum (PETM; 55.8 Ma) sediments on the New Jersey coastal plain. Here, using transmission electron microscopic observations, we present evidence for abundant giant magnetofossils, including previously reported elongated prisms and spindles, and new giant bullet-shaped magnetite crystals, in the Southern Ocean near Antarctica, not only during the PETM, but also shortly before and after the PETM. Moreover, we have discovered giant bullet-shaped magnetite crystals from the equatorial Indian Ocean during the Mid-Eocene Climatic Optimum (˜40 Ma). Our results indicate a more widespread geographic, environmental, and temporal distribution of giant magnetofossils in the geological record with a link to "hyperthermal" events. Enhanced global weathering during hyperthermals, and expanded suboxic diagenetic environments, probably provided more bioavailable iron that enabled biomineralization of giant magnetofossils. Our micromagnetic modelling indicates the presence of magnetic multi-domain (i.e., not ideal for navigation) and single domain (i.e., ideal for navigation) structures in the giant magnetite particles depending on their size, morphology and spatial arrangement. Different giant magnetite crystal morphologies appear to have had different biological functions, including magnetotaxis and other non-navigational purposes. Our observations suggest that hyperthermals provided ideal conditions for

  9. Two giant stellar complexes

    NASA Astrophysics Data System (ADS)

    Efremov, Yu. N.; Efremov, E. Yu.

    Common star complexes are huge (0.3-1 kpc in diameter) groups of relatively young stars, associations and clusters. The complexes usually form regular chains along spiral arms of grand design galaxies, being evidently formed and supported by magneto- gravitational instability developing along an arm. Special attention is given to a few large complexes which have signatures of gravitational boundness, such as round shape and high central density. Concentrations of stars and clusters in such a complex in M51 galaxy were found in this paper; we concluded it is possible to suggest that the complex is gravitationally bound. It is also stressed that some properties of the giant complex in NGC 6946 (such as its semicircular and sharp Western edge) are still enigmatic.

  10. Giant facial lymphangioma.

    PubMed

    Sanger, Claire; Wong, Lindsey; Wood, Jeyhan; David, Lisa R; Argenta, Louis C

    2011-07-01

    Lymphatic malformation (LM) is a benign cystic entity resulting from aberrant lymphatic drainage. Often evident at birth, most LMs have declared themselves by 2 years of age. They can be concerning when they occur near vital structures such as the airway or orbit. The natural history varies considerable from spontaneous gradual regression to long-term growth and debilitation. Depending on the location, structures involved, and clinical course of the LM, therapeutic options include observation, intralesional sclerosis, laser therapy, and surgical excision. The literature provides guidelines for treatment options that must be carefully applied to the facial region. We present a newborn infant who presented to our institution with giant facial lymphangioma who underwent a combination of sclerosis, laser ablation, and surgery with reconstruction. PMID:21772195

  11. [Giant adrenal myelolipoma].

    PubMed

    El Mejjad, Amine; Fekak, Hamid; Dakir, Mohamed; Sarf, Ismail; Manni, Ahmed; Meziane, Fethi

    2004-02-01

    Adrenal myelolipoma is a rare, benign, non-secreting tumour composed of adipose and haematopoietic tissue. The authors report a rare case of giant adrenal myelolipoma in a 53-year-old patient presenting with low back pain and a palpable flank mass on examination. CT scan suggested the diagnosis and surgical resection was indicated in view of the size and symptomatic nature of this mass. Histological examination confirmed the diagnosis. The outcome was favourable without recurrence after a follow-up of one year. The diagnosis of adrenal myelolipoma is based on radiology. Conservative management is generally sufficient for small asymptomatic tumours, but resection is required for large (> 5 cm) and/or symptomatic tumours. PMID:15098761

  12. Electric dipole transition moments and permanent dipole moments for spin-orbit configuration interaction wave functions

    NASA Astrophysics Data System (ADS)

    Roostaei, B.; Ermler, W. C.

    2012-03-01

    A procedure for calculating electric dipole transition moments and permanent dipole moments from spin-orbit configuration interaction (SOCI) wave functions has been developed in the context of the COLUMBUS ab initio electronic structure programs. The SOCI procedure requires relativistic effective core potentials and their corresponding spin-orbit coupling operators to define the molecular Hamiltonian, electric dipole transition moment and permanent dipole moment matrices. The procedure can be used for any molecular system for which the COLUMBUS SOCI circuits are applicable. Example applications are reported for transition moments and dipole moments for a series of electronic states of LiBe and LiSr defined in diatomic relativistic ωω-coupling.

  13. Plasmon-Induced Resonant Energy Transfer: a coherent dipole-dipole coupling mechanism

    NASA Astrophysics Data System (ADS)

    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.

  14. Laser-Induced Magnetic Dipole Spectroscopy.

    PubMed

    Hintze, Christian; Bücker, Dennis; Domingo Köhler, Silvia; Jeschke, Gunnar; Drescher, Malte

    2016-06-16

    Pulse electron paramagnetic resonance measurements of nanometer scale distance distributions have proven highly effective in structural studies. They exploit the magnetic dipole-dipole coupling between spin labels site-specifically attached to macromolecules. The most commonly applied technique is double electron-electron resonance (DEER, also called pulsed electron double resonance (PELDOR)). Here we present the new technique of laser-induced magnetic dipole (LaserIMD) spectroscopy based on optical switching of the dipole-dipole coupling. In a proof of concept experiment on a model peptide, we find, already at a low quantum yield of triplet excitation, the same sensitivity for measuring the distance between a porphyrin and a nitroxide label as in a DEER measurement between two nitroxide labels. On the heme protein cytochrome C, we demonstrate that LaserIMD allows for distance measurements between a heme prosthetic group and a nitroxide label, although the heme triplet state is not directly observable by an electron spin echo. PMID:27163749

  15. Pygmy Dipole Strength in Exotic Nuclei and the Equation of State

    NASA Astrophysics Data System (ADS)

    Klimkiewicz, A.; Paar, N.; Adrich, P.; Fallot, M.; le Bleis, T.; Rossi, D.; Boretzky, K.; Aumann, T.; Alvarez-Pol, H.; Aksouh, F.; Benlliure, J.; Berg, T.; Boehmer, M.; Casarejos, E.; Chartier, M.; Chatillon, A.; Cortina-Gil, D.; Pramanik, U. Datta; Elze, Th. W.; Emling, H.; Ershova, O.; Fernando-Dominguez, B.; Geissel, H.; Gorska, M.; Heil, M.; Hellström, M.; Johansson, H.; Jones, K. L.; Junghans, A.; Kiselev, O.; Kratz, J. V.; Kulessa, R.; Kurz, N.; Labiche, M.; Lemmon, R.; Litvinov, Y.; Mahata, K.; Maierbeck, P.; Nilsson, T.; Nociforo, C.; Palit, R.; Paschalis, S.; Plag, R.; Reifarth, R.; Simon, H.; Sümmerer, K.; Surówka, G.; Vretenar, D.; Wagner, A.; Waluś, W.; Weick, H.; Winkler, M.

    2009-08-01

    A concentration of dipole strength at energies below the giant dipole resonance was observed in neutron-rich nuclei around 132Sn in an experiment using the FRS-LAND setup. This so-called "pygmy" dipole strength can be related to the parameters of the symmetry energy and to the neutron skin thickness on the grounds of a relativistic quasiparticle random-phase approximation. Using this ansatz and the experimental findings for 130Sn and 132Sn, we derive a value of the symmetry energy pressure of p¯0 = 2.2±0.5 MeV/fm3. Neutron skin thicknesses of Rn-Rp = 0.23±0.03 fm and 0.24±0.03 fm for 130Sn and 132Sn, respectively, have been determined. Preliminary results on 68Ni from a similar experiment using an improved setup indicate an enhanced cross section at low energies, while the results for 58Ni are in accordance with results from photoabsorption measurements.

  16. The effect of a permanent dipole moment on the polar molecule cavity quantum electrodynamics

    NASA Astrophysics Data System (ADS)

    Jing-Yun, Zhao; Li-Guo, Qin; Xun-Ming, Cai; Qiang, Lin; Zhong-Yang, Wang

    2016-04-01

    A dressed-state perturbation theory beyond the rotating wave approximation (RWA) is presented to investigate the interaction between a two-level electronic transition of polar molecules and a quantized cavity field. Analytical expressions can be explicitly derived for both the ground- and excited-state-energy spectrums and wave functions of the system, where the contribution of permanent dipole moments (PDM) and the counter-rotating wave term (CRT) can be shown separately. The validity of these explicit results is discussed by comparison with the direct numerical simulation. Compared to the CRT coupling, PDM results in the coupling of more dressed states and the energy shift is proportional to the square of the normalized permanent dipole difference, and a greater Bloch–Siegert shift can be produced in the giant dipole molecule cavity QED. In addition, our method can also be extended to the solution of the two-level atom Rabi model Hamiltonian beyond the RWA. Project supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB01010200), the Hundred Talents Program of the Chinese Academy of Sciences (Grant No. Y321311401), the National Natural Science Foundation of China (Grant Nos. 61475139, 11347147, and 11247014), the National Basics Research Program of China (Grant No. 2013CB329501), and the Zhejiang Provincial Natural Science Foundation (Grant No. LQ13A040006).

  17. Electron-pinned defect-dipoles for high-performance colossal permittivity materials

    NASA Astrophysics Data System (ADS)

    Hu, Wanbiao; Liu, Yun; Withers, Ray L.; Frankcombe, Terry J.; Norén, Lasse; Snashall, Amanda; Kitchin, Melanie; Smith, Paul; Gong, Bill; Chen, Hua; Schiemer, Jason; Brink, Frank; Wong-Leung, Jennifer

    2013-09-01

    The immense potential of colossal permittivity (CP) materials for use in modern microelectronics as well as for high-energy-density storage applications has propelled much recent research and development. Despite the discovery of several new classes of CP materials, the development of such materials with the required high performance is still a highly challenging task. Here, we propose a new electron-pinned, defect-dipole route to ideal CP behaviour, where hopping electrons are localized by designated lattice defect states to generate giant defect-dipoles and result in high-performance CP materials. We present a concrete example, (Nb+In) co-doped TiO2 rutile, that exhibits a largely temperature- and frequency-independent colossal permittivity (> 104) as well as a low dielectric loss (mostly < 0.05) over a very broad temperature range from 80 to 450 K. A systematic defect analysis coupled with density functional theory modelling suggests that ‘triangular’ In23+VO••Ti3+ and ‘diamond’ shaped Nb25+Ti3+ATi (A  =  Ti3+/In3+/Ti4+) defect complexes are strongly correlated, giving rise to large defect-dipole clusters containing highly localized electrons that are together responsible for the excellent CP properties observed in co-doped TiO2. This combined experimental and theoretical work opens up a promising feasible route to the systematic development of new high-performance CP materials via defect engineering.

  18. Atmospheres of Extrasolar Giant Planets

    NASA Technical Reports Server (NTRS)

    Marley, Mark

    2006-01-01

    The next decade will almost certainly see the direct imaging of extrasolar giant planets around nearby stars. Unlike purely radial velocity detections, direct imaging will open the door to characterizing the atmosphere and interiors of extrasola planets and ultimately provide clues on their formation and evolution through time. This process has already begun for the transiting planets, placing new constraints on their atmospheric structure, composition, and evolution. Indeed the key to understanding giant planet detectability, interpreting spectra, and constraining effective temperature and hence evolution-is the atmosphere. I will review the universe of extrasolar giant planet models, focusing on what we have already learned from modeling and what we will likely be able to learn from the first generation of direct detection data. In addition to these theoretical considerations, I will review the observations and interpretation of the - transiting hot Jupiters. These objects provide a test of our ability to model exotic atmospheres and challenge our current understanding of giant planet evolution.

  19. Landscape of the lost giants

    NASA Astrophysics Data System (ADS)

    2013-09-01

    The Pleistocene megafauna extinction erased a group of remarkable animals. Whether humans had a prominent role in the extinction remains controversial, but it is emerging that the disappearance of the giants has markedly affected the environment.

  20. Pharma giants swap research programs.

    PubMed

    2014-07-01

    Pharmaceutical giants Novartis and GlaxoSmithKline (GSK) agreed in late April to swap some assets, with Novartis handing off its vaccine business to GSK and getting most of the British company's cancer portfolio in return. PMID:25002632

  1. Bunched beam longitudinal instability: Coherent dipole motion

    SciTech Connect

    Zhang, S.Y.; Weng, W.T.

    1993-04-23

    In this paper, the authors present a new formulation for the longitudinal coherent dipole motion, where a quadrature response of the environmental impedance is shown to be the effective longitudinal impedance for the beam instability. The Robinson-Pedersen formulation for the longitudinal dipole motion is also presented, the difference of the two approaches is discussed in the comparison. The results by using the Sacherer integral equation for the coherent dipole motion can generate the same results as by using the other two approaches, except for a scaling difference. The formulation is further generalized to the rigid bunch motion using signal analysis method, where a form factor shows up naturally. Finally, the formulation is applied to solve the coupled bunch instabilities. Examples of the AGS Booster and the AGS coupled bunch instabilities are used to illustrate the applications of the formulation.

  2. Relationships between dipole moments of diatomic molecules.

    PubMed

    Hou, Shilin; Bernath, Peter F

    2015-02-14

    The dipole moment is one of the most important physical properties of a molecule. We present a combination rule for the dipole moments of related diatomic molecules. For molecules AB, AX, BY, and XY from two different element groups in the periodic table, if their elements make a small parallelogram, reliable predictions can be obtained. Our approach is particularly useful for systems with heavy atoms. For a large set of molecules tested, the average difference of the prediction from experimental data is less than 0.2 debye (D). The dipole moments for heavy molecules such as GaCl, InBr, SrCl, and SrS, for which no experimental data are available at present, are predicted to be 3.17, 3.76, 3.85 and 11.54 D, respectively. PMID:25588998

  3. Acoustic Scattering by a Vortex Dipole

    NASA Astrophysics Data System (ADS)

    Zheng, Zhongquan; Zhang, Junjian

    2015-11-01

    Acoustic scattering in vortical flow has been an interesting and practical topic, with applications in problems such as acoustic scattering of turbulent flow. In this study, the linearized Euler equation model is employed to investigate sound wave propagation over a subsonic counter-rotating vortex dipole. Both the stationary and moving due to mutual induction vortex dipoles are studied. The numerical scheme uses a high-order WENO scheme to accommodate the highly convective background flow at high Mach numbers. The simulation results are compared with the analytical solutions and literature data. The theoretical study is focused on the effects of three characteristic length scales in this problem: the incident sound wave length, the vortex core size, and the vortex dipole size. The directivity and scaling laws related to the vortex scattering effects are discussed.

  4. Overview of the Levitated Dipole Experiment

    NASA Astrophysics Data System (ADS)

    Mauel, M. E.; Garnier, D. T.; Hansen, A.; Pedersen, T. Sunn; Kesner, J.; Jones, C. M.; Karim, I.; Liptac, J.; Minervini, J.; Michael, P.; Radovinsky, A.; Schultz, J. H.; Smith, B. A.; Zhukovsky, A.

    2001-10-01

    The Levitated Dipole Experiment (LDX) [http://www.psfc.mit.edu/ldx/] will be the first experiment able to study high-beta plasma confined by a magnetic dipole with near classical energy confinement. LDX consists of three superconducting magnets and illustrates the role of innovative magnetic technology that makes possible explorations of entirely new confinement concepts. We describe the LDX machine design and detail the fabrication status of the superconducting floating-coil, charging-coil, and levitation-coil. In addition, we summarize (1) our procedure to cool, to inductively charge, and to levitate the 1.3 MA floating coil, (2) our initial diagnostic set, and (3) our experimental and physics plans that answer the key questions of high-beta stability and confinement in the dipole fusion concept.

  5. Observation of the dipole-dipole interaction between cold Rydberg atoms by microwave spectroscopy

    NASA Astrophysics Data System (ADS)

    Park, Hyunwook

    We measured the dipole-dipole interaction between nsnp pairs of atoms by the line broadening technique. The broadening rate relies on the atomic density, equivalently the average internuclear spacing Rav, and principal quantum number n. This measurement of the dipole-dipole broadening can be expressed in terms of n and provides a simple measure of line broadening due to increased atomic density in laboratory units. Calculation of the dipole-dipole interaction was compared to the observations. It was realized that the observations, which have smaller broadening rates than the calculation, stem from the spin-orbit coupling, which results in the shift-free and small-shift dipole-dipole energy levels as well as normal shift levels. As a result of the dipole-dipole interaction, the nsnp molecules form attractive and repulsive dipole-dipole potentials in which atoms are forced to move toward each other and farther apart, respectively. These motions of the atoms in the dipole potentials induce collisional ionization and trigger plasma formation from Rydberg atoms. The collisional ionization was systematically investigated by comparing the effects of the attractive, repulsive, and almost flat potentials. It turned out that atoms transferred to the attractive potential are ionized in a few microseconds, while those on the repulsive potential are not significantly ionized, similar to the flat potential case. Essentially the same result was observed again with an enhanced ion signal by extending the sampling to a broader range of internuclear separation via high microwave power. We also detected plasma fields by using the exaggerated property of Rydberg atoms responding to external electric fields. Rydberg atoms were injected into a plasma cloud, and the ns -- np microwave transition was driven to detect the plasma fields by measuring Stark shifts. We were able to measure a microscopic field as small as 0.1 V/cm. In the presence of a strong macroscopic field, the resonances

  6. Photoelectron spectroscopy and the dipole approximation

    SciTech Connect

    Hemmers, O.; Hansen, D.L.; Wang, H.

    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.

  7. Kuiper Prize: Giant Planet Atmospheres

    NASA Astrophysics Data System (ADS)

    Ingersoll, Andrew P.

    2007-10-01

    The study of giant planet atmospheres is near and dear to me, for several reasons. First, the giant planets are photogenic; the colored clouds are great tracers, and one can make fantastic movies of the atmosphere in motion. Second, the giant planets challenge us with storms that last for hundreds of years and winds that blow faster the farther you go from the sun. Third, they remind us of Earth with their hurricanes, auroras, and lightning, but they also are the link to the 200 giant planets that have been discovered around other stars. This talk will cover the past, present, and future (one hopes) of giant planet research. I will review the surprises of the Voyager and Galileo eras, and will discuss what we are learning now from the Cassini orbiter. I will review the prospects for answering the outstanding questions like: Where's the water? What is providing the colors of the clouds? How deep do the features extend? Where do the winds get their energy? What is the role of the magnetic field? Finally, I will briefly discuss how extrasolar giant planets compare with objects in our own solar system.

  8. Giant and Low-Energy Dipole Modes in Neutron-Rich Nuclei

    NASA Astrophysics Data System (ADS)

    Rossi, D. M.; Adrich, P.; Aksouh, F.; Alvarez-Pol, H.; Aumann, T.; Benlliure, J.; Böhmer, M.; Boretzky, K.; Casarejos, E.; Chartier, M.; Chatillon, A.; Cortina-Gil, D.; Datta Pramanik, U.; Emling, H.; Ershova, O.; Fernandez-Dominguez, B.; Geissel, H.; Gorska, M.; Heil, M.; Johansson, H.; Junghans, A.; Kiselev, O.; Klimkiewicz, A.; Kratz, J. V.; Kurz, N.; Labiche, M.; Le Bleis, T.; Lemmon, R.; Litvinov, Yu. A.; Mahata, K.; Maierbeck, P.; Movsesyan, A.; Nilsson, T.; Nociforo, C.; Palit, R.; Paschalis, S.; Plag, R.; Reifarth, R.; Simon, H.; Sümmerer, K.; Wagner, A.; Walus, W.; Weick, H.; Winkler, M.

    2014-09-01

    The E1 strength of exotic Ni isotopes has been measured at the R3B-LAND setup at GSI in Darmstadt. The experimental method relied on Coulomb excitation in inverse kinematics, for beam energies around 500 MeV/u. The excitation energy was reconstructed using the invariant mass, enabling the observation of the GDR and of additional low-lying E1 strength. The analysis of the neutron kinetic energies also allowed the extraction of the branching ratio for the direct neutron decay of 68Ni, amounting to 25(2)%.

  9. Bound free electron-positron pair production accompanied by giant dipole resonances

    SciTech Connect

    Senguel, M. Y.; Gueclue, M. C.

    2011-01-15

    At the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC), for example, virtual photons produce many particles. At small impact parameters where the colliding nuclei make peripheral collisions, photon fluxes are very large and these are responsible for the multiple photonuclear interactions. Free pair productions, bound free pair productions, and nuclear Coulomb excitations are important examples of such interactions, and these processes play important roles in the beam luminosity at RHIC and LHC. Here we obtained the impact parameter dependence of bound free pair production cross sections and by using this probability we obtained bound free electron-positron pair production with nuclear breakup for heavy ion collisions at RHIC and LHC. We also compared our results to the other calculations.

  10. Yields of photoneutron reactions on {sup 197}Au nuclei in the giant-dipole-resonance region

    SciTech Connect

    Belyshev, S. S.; Ermakov, A. N.; Ishkhanov, B. S.; Kuznetsov, A. A.; Kurilik, A. S.; Stopani, K. A.; Troschiev, S. Yu.

    2011-11-15

    Yields of photonuclear reactions on 197Au nuclei were measured in a beam of bremsstrahlung photons, the endpoint energy of the bremsstrahlung spectrum being 29.1 MeV. These measurements were performed by means of the gamma-activation procedure. The results obtained in this way were compared with the results of earlier experiments and theoretical calculations.

  11. Waves in space plasma dipole antenna subsystem

    NASA Technical Reports Server (NTRS)

    Thomson, Mark

    1993-01-01

    The Waves In Space Plasma (WISP) flight experiment requires a 50-meter-long deployable dipole antenna subsystem (DASS) to radiate radio frequencies from the STS Orbiter cargo bay. The transmissions are to excite outer ionospheric plasma between the dipole and a free-flying receiver (Spartan) for scientific purposes. This report describes the singular DASS design requirements and how the resulting design satisfies them. A jettison latch is described in some detail. The latch releases the antenna in case of any problems which might prevent the bay doors from closing for re-entry and landing of the Orbiter.

  12. Microstrip dipole antennas on electrically thick substrates

    NASA Astrophysics Data System (ADS)

    Jackson, D. R.; Alexopoulos, N. G.

    1985-10-01

    Printed circuit antennas are attractive radiation sources both at microwave and millimeter wave frequencies. However, for millimeter wave applications where the substrate is likely to be electrically thick, it is important to understand the basic effects of a thick substrate on radiation characteristics. In particular, it is concluded here that dipole radiation properties become sensitive to loss as the substrate becomes thick. Furthermore, the efficiency of dipoles on thick substrates tends to be low, especially as the dielectric constant of the substrate increases. A method of improving both the efficiency and gain can be used for thick substrates, however, which uses a superstrate layer on top of the antenna.

  13. Dipole strength distributions from HIGS Experiments

    NASA Astrophysics Data System (ADS)

    Werner, V.; Cooper, N.; Goddard, P. M.; Humby, P.; Ilieva, R. S.; Rusev, G.; Beller, J.; Bernards, C.; Crider, B. P.; Isaak, J.; Kelley, J. H.; Kwan, E.; Löher, B.; Peters, E. E.; Pietralla, N.; Romig, C.; Savran, D.; Scheck, M.; Tonchev, A. P.; Tornow, W.; Yates, S. W.; Zweidinger, M.

    2015-05-01

    A series of photon scattering experiments has been performed on the double-beta decay partners 76Ge and 76Se, in order to investigate their dipole response up to the neutron separation threshold. Gamma-ray beams from bremsstrahlung at the S-DALINAC and from Compton-backscattering at HIGS have been used to measure absolute cross sections and parities of dipole excited states, respectively. The HIGS data allows for indirect measurement of averaged branching ratios, which leads to significant corrections in the observed excitation cross sections. Results are compared to statistical calculations, to test photon strength functions and the Axel-Brink hypothesis

  14. Real Compton scattering via color dipoles

    SciTech Connect

    Kopeliovich, B. Z.; Schmidt, Ivan; Siddikov, M.

    2009-09-01

    We study the photoabsorption reaction and real Compton scattering within the color dipole model. We rely on a photon wave function derived in the instanton-vacuum model and on the energy-dependent phenomenological elastic dipole amplitude. Data for the photoabsorption cross section at high energies agree with our parameter-free calculations. We also provide predictions for the differential real Compton scattering cross section. Although no data for small angle Compton scattering are available so far, this process can be measured in ultraperipheral hadronic and nuclear collisions at the LHC.

  15. Neutron electric dipole moment and CP

    SciTech Connect

    Chang, Darwin; Chang, We-Fu; Frank, Mariana; Keung, Wai-Yee

    2000-11-01

    We analyze the neutron electric dipole moment (EDM) in the minimal supersymmetric standard model with explicit R-parity violating terms. The leading contribution to the EDM occurs at the two-loop level and is dominated by the chromoelectric dipole moments of quarks, assuming there is no tree-level mixings between sleptons and Higgs bosons or between leptons and gauginos. Based on the experimental constraint on the neutron EDM, we set limits on the imaginary parts of complex couplings {lambda}{sub ijk}{prime} and {lambda}{sub ijk} due to the virtual b loop or {tau} loop.

  16. Microwave observations of the dipole-dipole interaction between cold Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Afrousheh, K.; Bohlouli, P. Z.; Vagale, D.; Fedorov, M.; Mugford, A.; Martin, J. D. D.

    2004-05-01

    Neighboring Rydberg atoms may strongly interact through electric dipole-dipole couplings. Thus, temporary excitation to Rydberg states has been proposed for implementing elements of quantum information processing using cold neutral atoms. In this work we excited Rb atoms in a MOT to the 45d_5/2 Rydberg state. A microwave pulse was then used to transfer a variable amount of 45d_5/2 atoms to the 46p_3/2 state. Atoms in the 45d and 46p states strongly interact through an always resonant dipole-dipole interaction. We probe this by introducing a second microwave pulse which drives the 45d_5/2-46d_5/2 two photon transition. The dipole-dipole interaction between 46d and 46p states is relatively weak, so the observed spectra are dominated by the 45d-46p couplings between neighboring atoms. These results are discussed in the context of dipole-blockade, as proposed by Lukin et al., Phys. Rev. Lett., 87, 37901 (2001).

  17. Dipole-dipole interactions in optical lattices do not follow an inverse cube power law

    NASA Astrophysics Data System (ADS)

    Wall, M. L.; Carr, L. D.

    2013-12-01

    We study the effective dipole-dipole interactions in ultracold quantum gases on optical lattices as a function of asymmetry in confinement along the principal axes of the lattice. In particular, we study the matrix elements of the dipole-dipole interaction in the basis of lowest band Wannier functions which serve as a set of low-energy states for many-body physics on the lattice. We demonstrate that, for shallow lattices in quasi-reduced dimensional scenarios, the effective interaction between dipoles in an optical lattice is non-algebraic in the inter-particle separation at short to medium distance on the lattice scale and has a long-range power-law tail, in contrast to the pure power-law behavior of the dipole-dipole interaction in free space. The modifications to the free-space interaction can be sizable; we identify differences of up to 36% from the free-space interaction at the nearest-neighbor distance in quasi-one-dimensional arrangements. The interaction difference depends essentially on asymmetry in confinement, due to the d-wave anisotropy of the dipole-dipole interaction. Our results do not depend on statistics, applying to both dipolar Bose-Einstein condensates and degenerate Fermi gases. Using matrix product state simulations, we demonstrate that use of the correct lattice dipolar interaction leads to significant deviations from many-body predictions using the free-space interaction. Our results are relevant to up and coming experiments with ultracold heteronuclear molecules, Rydberg atoms and strongly magnetic atoms in optical lattices.

  18. Entanglement between two atoms in the presence of dipole-dipole interaction and atomic coherence

    NASA Astrophysics Data System (ADS)

    Bashkirov, Eugene K.; Litvinova, Darya V.

    2015-03-01

    We have investigated the influence of dipole-dipole interaction and initial atomic coherence on dynamics of two-atom systems. We have considered a model, in which only one atom is trapped in a cavity, and the other one can be spatially moved freely outside the cavity. We have shown the possibility of disappearance of the entanglement sudden death effect in the presence of the dipole interaction of atoms. We have also derived that the initial atomic coherence can be used for effective control of the degree of the atom-atom entanglement.

  19. Giant retinal tears.

    PubMed

    Shunmugam, Manoharan; Ang, Ghee Soon; Lois, Noemi

    2014-01-01

    A giant retinal tear (GRT) is a full-thickness neurosensory retinal break that extends circumferentially around the retina for three or more clock hours in the presence of a posteriorly detached vitreous. Its incidence in large population-based studies has been estimated as 1.5% of rhegmatogenous retinal detachments, with a significant male preponderance, and bilaterality in 12.8%. Most GRTs are idiopathic, with trauma, hereditary vitreoretinopathies and high myopia each being causative in decreasing frequency. The vast majority of GRTs are currently managed with a pars plana vitrectomy; the use of adjunctive circumferential scleral buckling is debated, but no studies have shown a clear anatomical or visual advantage with its use. Similarly, silicone oil tamponade does not influence long-term outcomes when compared with gas. Primary and final retinal reattachment rates are achieved in 88% and 95% of patients, respectively. Even when the retina remains attached, however, visual recovery may be limited. Furthermore, fellow eyes of patients with a GRT are at higher risk of developing retinal tears and retinal detachment. Prophylactic treatment under these circumstances may be considered but there is no firm evidence of its efficacy at the present time. PMID:24138895

  20. Recurrent renal giant leiomyosarcoma

    PubMed Central

    Öziş, Salih Erpulat; Gülpınar, Kamil; Şahlı, Zafer; Konak, Baha Burak; Keskin, Mete; Özdemir, Süleyman; Ataoğlu, Ömür

    2016-01-01

    Primary renal leiomyosarcomas are rare, aggressive tumors. They constitute 1–2% of adult malignant renal tumors. Although leiomyosarcomas are the most common histological type (50–60%) of renal sarcomas, information on renal leiomyosarcoma is limited. Local or systemic recurrences are common. The radiological appearance of renal leiomyosarcomas is not specific, therefore renal leiomyosarcoma cannot be distinguished from renal cell carcinoma by imaging methods in all patients. A 74-year-old female patient presented to our clinic complaining of a palpable mass on the right side of her abdomen in November 2012. The abdominal magnetic resonance imaging revealed a mass, 25 × 24 × 23 cm in size. Her past medical history revealed that she has undergone right radical nephrectomy in 2007, due to a 11 × 12 × 13 cm renal mass that was then reported as renal cell carcinoma on abdominal magnetic resonance imaging, but the pathological diagnosis was low-grade renal leiomyosarcoma. The most recent follow-up of the patient was in 2011, with no signs of local recurrence or distant metastases within this four-year period. The patient underwent laparotomy on November 2012, and a 35 cm retroperitoneal mass was excised. The pathological examination of the mass was reported as high-grade leiomyosarcoma. The formation of this giant retroperitoneal mass in 1 year can be explained by the transformation of the lesion’s pathology from low-grade to a high-grade tumor.

  1. Relativistic quasiparticle time blocking approximation: Dipole response of open-shell nuclei

    NASA Astrophysics Data System (ADS)

    Litvinova, E.; Ring, P.; Tselyaev, V.

    2008-07-01

    The self-consistent relativistic quasiparticle random-phase approximation (RQRPA) is extended by the quasiparticle-phonon coupling (QPC) model using the quasiparticle time blocking approximation (QTBA). The method is formulated in terms of the Bethe-Salpeter equation (BSE) in the two-quasiparticle space with an energy-dependent two-quasiparticle residual interaction. This equation is solved either in the basis of Dirac states forming the self-consistent solution of the ground state or in the momentum representation. Pairing correlations are treated within the Bardeen-Cooper-Schrieffer (BCS) model with a monopole-monopole interaction. The same NL3 set of the coupling constants generates the Dirac-Hartree-BCS single-quasiparticle spectrum, the static part of the residual two-quasiparticle interaction and the quasiparticle-phonon coupling amplitudes. A quantitative description of electric dipole excitations in the chain of tin isotopes (Z=50) with the mass numbers A=100,106,114,116,120, and 130 and in the chain of isotones with (N=50) Sr88, Zr90, Mo92 is performed within this framework. The RQRPA extended by the coupling to collective vibrations generates spectra with a multitude of 2q⊗phonon (two quasiparticles plus phonon) states providing a noticeable fragmentation of the giant dipole resonance as well as of the soft dipole mode (pygmy resonance) in the nuclei under investigation. The results obtained for the photo absorption cross sections and for the integrated contributions of the low-lying strength to the calculated dipole spectra agree very well with the available experimental data.

  2. A unique advantage for giant eyes in giant squid.

    PubMed

    Nilsson, Dan-Eric; Warrant, Eric J; Johnsen, Sönke; Hanlon, Roger; Shashar, Nadav

    2012-04-24

    Giant and colossal deep-sea squid (Architeuthis and Mesonychoteuthis) have the largest eyes in the animal kingdom [1, 2], but there is no explanation for why they would need eyes that are nearly three times the diameter of those of any other extant animal. Here we develop a theory for visual detection in pelagic habitats, which predicts that such giant eyes are unlikely to evolve for detecting mates or prey at long distance but are instead uniquely suited for detecting very large predators, such as sperm whales. We also provide photographic documentation of an eyeball of about 27 cm with a 9 cm pupil in a giant squid, and we predict that, below 600 m depth, it would allow detection of sperm whales at distances exceeding 120 m. With this long range of vision, giant squid get an early warning of approaching sperm whales. Because the sonar range of sperm whales exceeds 120 m [3-5], we hypothesize that a well-prepared and powerful evasive response to hunting sperm whales may have driven the evolution of huge dimensions in both eyes and bodies of giant and colossal squid. Our theory also provides insights into the vision of Mesozoic ichthyosaurs with unusually large eyes. PMID:22425154

  3. Giant resonances in {sup 238}U within the quasiparticle random-phase approximation with the Gogny force

    SciTech Connect

    Peru, S.; Gosselin, G.; Martini, M.; Dupuis, M.; Hilaire, S.

    2011-01-15

    Fully consistent axially-symmetric deformed quasiparticle random-phase approximation (QRPA) calculations have been performed, using the same Gogny D1S effective force for both the Hartree-Fock-Bogolyubov mean field and QRPA matrix. New implementation of this approach leads to the applicability of QRPA to heavy deformed nuclei. Giant resonances and low-energy collective states for monopole, dipole, quadrupole, and octupole modes are predicted for the heavy deformed nucleus {sup 238}U and compared with experimental data.

  4. Effect of dipole-dipole interaction on self-control magnetization oscillation in double-domain nanomagnets

    NASA Astrophysics Data System (ADS)

    Gao, Y. J.; Guo, Y. J.; Liu, J.-M.

    2012-03-01

    A double-domain model with long-range dipole-dipole interaction is proposed to investigate the self-oscillation of magnetization in nano-magnetic systems driven by self-controlled spin-polarized current. The dynamic behavior of magnetization oscillation is calculated by a modified Landau-Lifshitz-Gilbert equation in order to evaluate the effects of the long-range dipole-dipole interaction. While the self-oscillation of magnetization can be maintained substantially, several self-oscillation regions are experienced as the dipole-dipole interaction increases gradually.

  5. Electromagnetic Force on a Moving Dipole

    ERIC Educational Resources Information Center

    Kholmetskii, Alexander L.; Missevitch, Oleg V.; Yarman, T.

    2011-01-01

    We analyse the force acting on a moving dipole due to an external electromagnetic field and show that the expression derived in Vekstein (1997 "Eur. J. Phys." 18 113) is erroneous and suggest the correct equation for the description of this force. We also discuss the physical meaning of the relativistic transformation of current for a closed…

  6. Dipole operator constraints on composite Higgs models

    NASA Astrophysics Data System (ADS)

    König, Matthias; Neubert, Matthias; Straub, David M.

    2014-07-01

    Flavour- and CP-violating electromagnetic or chromomagnetic dipole operators in the quark sector are generated in a large class of new physics models and are strongly constrained by measurements of the neutron electric dipole moment and observables sensitive to flavour-changing neutral currents, such as the branching ratio and . After a model-independent discussion of the relevant constraints, we analyze these effects in models with partial compositeness, where the quarks get their masses by mixing with vector-like composite fermions. These scenarios can be seen as the low-energy limit of composite Higgs or warped extra dimensional models. We study different choices for the electroweak representations of the composite fermions motivated by electroweak precision tests as well as different flavour structures, including flavour anarchy and or flavour symmetries in the strong sector. In models with "wrong-chirality" Yukawa couplings, we find a strong bound from the neutron electric dipole moment, irrespective of the flavour structure. In the case of flavour anarchy, we also find strong bounds from flavour-violating dipoles, while these constraints are mild in the flavour-symmetric models.

  7. Analysis of a microstrip dipole antenna

    NASA Astrophysics Data System (ADS)

    Rao, B. V.; Sabhnani, N. H.

    1984-02-01

    Assuming a quasi-TEM mode of wave propagation and using a conformal transformation technique, accurate and simple analytic expressions for the characteristic wave resistance and the effective dielectric constant of the microstrip dipole antenna in the mixed dielectric medium have been derived. The theoretical values are in close agreement with the experimental results.

  8. Efficient analysis for infinite microstrip dipole arrays

    NASA Astrophysics Data System (ADS)

    Wright, S. M.; Lo, Y. T.

    1983-11-01

    A moment method analysis of infinite microstrip dipole arrays which uses an efficient technique to evaluate the generalized impedance matrix is described. A particularly simple formulation is obtained through the use of the periodic Green function. Results for the reflection coefficient magnitude against scan angle are given for a typical array.

  9. The Case of the Disappearing Magnetic Dipole

    ERIC Educational Resources Information Center

    Gough, W.

    2008-01-01

    The problem of an oscillating magnetic dipole at the centre of a lossless dielectric spherical shell is considered. For simplicity, the free-space wavelength is taken to be much greater than the shell radii, but the relative permittivity [epsilon][subscript r] of the shell is taken as much greater than unity, so the wavelength in the shell could…

  10. Dipole nano-laser: Theory and properties

    SciTech Connect

    Ghannam, T.

    2014-03-31

    In this paper we outline the main quantum properties of the system of nano-based laser called Dipole Nano-Laser emphasizing mainly on its ability to produce coherent light and for different configurations such as different embedding materials and subjecting it to an external classical electric field.

  11. A Microstrip Reflect Array Using Crossed Dipoles

    NASA Technical Reports Server (NTRS)

    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.

  12. Pygmy dipole response of proton-rich argon nuclei in random-phase approximation and no-core shell model

    SciTech Connect

    Barbieri, C.; Martinez-Pinedo, G.; Caurier, E.; Langanke, K.

    2008-02-15

    The occurrence of a pygmy dipole resonance in proton rich {sup 32,34}Ar is studied using the unitary correlator operator method interaction V{sub UCOM}, based on Argonne V18. Predictions from the random-phase approximation (RPA) and the shell model in a no-core basis are compared. It is found that the inclusion of configuration mixing up to two-particles-two-holes broadens the pygmy strength slightly and reduces sensibly its strength, as compared to the RPA predictions. For {sup 32}Ar, a clear peak associated with a pygmy resonance is found. For {sup 34}Ar, the pygmy states are obtained close to the giant dipole resonance and mix with it.

  13. Evidence of dynamical dipole excitation in the fusion-evaporation of the 40Ca+152Sm heavy system

    NASA Astrophysics Data System (ADS)

    Parascandolo, C.; Pierroutsakou, D.; Alba, R.; Del Zoppo, A.; Maiolino, C.; Santonocito, D.; Agodi, C.; Baran, V.; Boiano, A.; Colonna, M.; Coniglione, R.; De Filippo, E.; Di Toro, M.; Emanuele, U.; Farinon, F.; Guglielmetti, A.; Inglima, G.; La Commara, M.; Martin, B.; Mazzocchi, C.; Mazzocco, M.; Rizzo, C.; Romoli, M.; Sandoli, M.; Signorini, C.; Silvestri, R.; Soramel, F.; Strano, E.; Torresi, D.; Trifirò, A.; Trimarchi, M.

    2016-04-01

    The excitation of the dynamical dipole mode along the fusion path was investigated for the first time in the formation of a heavy compound nucleus in the A ˜190 mass region. The compound nucleus was formed at identical conditions of excitation energy and spin from two entrance channels: the charge-asymmetric 40Ca+152Sm and the nearly charge-symmetric 48Ca+144Sm at Elab=11 and 10.1 MeV/nucleon, respectively. High-energy γ rays and light charged particles were measured in coincidence with evaporation residues by means of the MEDEA multidetector array (Laboratori Nazionali del Sud, Italy) coupled to four parallel plate avalanche counters. The charged particle multiplicity spectra and angular distributions were used to pin down the average excitation energy, the average mass, and the average charge of the compound nucleus. The γ -ray multiplicity spectrum and angular distribution related to the nearly charge-symmetric channel were employed to obtain new data on the giant dipole resonance in the compound nucleus. The dynamical dipole mode excitation in the charge-asymmetric channel was evidenced, in a model-independent way, by comparing the γ -ray multiplicity spectra and angular distributions of the two entrance channels with each other. Calculations of the dynamical dipole mode in the 40Ca+152Sm channel, based on a collective bremsstrahlung analysis of the reaction dynamics, are presented. Possible interesting implications in the superheavy-element quest are discussed.

  14. The asteroseismic signature of strong magnetic fields in the cores of red giant stars

    NASA Astrophysics Data System (ADS)

    Fuller, Jim; Cantiello, Matteo; Stello, Dennis; Garcia, Rafael; Bildsten, Lars

    2016-01-01

    Internal stellar magnetic fields are inaccessible to direct observations and little is known about their amplitude, geometry and evolution. I will discuss how strong magnetic fields in the cores of red giant stars can be identified with asteroseismology. The fields manifest themselves via depressed dipole stellar oscillation modes, which arises from a magnetic greenhouse effect that scatters and traps oscillation mode energy within the core of the star. Physically, the effect stems from magnetic tension forces created by sufficiently strong fields, which break the spherical symmetry of the wave propagation cavity. The loss of wave energy within the core reduces the mode visibility at the stellar surface, and we find that our predicted visibilities are in excellent agreement with a class of red giants exhibiting depressed dipole oscillation modes. The Kepler satellite has already observed hundreds of these red giants, which we identify as stars with strongly magnetized cores. Field strengths larger than roughly 10^5 G can produce the observed depression, and in one case we measure a core field strength of 10^7 G.

  15. Spectroscopic Observation of Resonant Electric Dipole-Dipole Interactions between Cold Rydberg Atoms

    NASA Astrophysics Data System (ADS)

    Afrousheh, K.; Bohlouli-Zanjani, P.; Vagale, D.; Mugford, A.; Fedorov, M.; Martin, J. D.

    2004-11-01

    Resonant electric dipole-dipole interactions between cold Rydberg atoms were observed using microwave spectroscopy. Laser-cooled 85Rb atoms in a magneto-optical trap were optically excited to 45d5/2 Rydberg states using a pulsed laser. A microwave pulse transferred a fraction of these Rydberg atoms to the 46p3/2 state. A second microwave pulse then drove atoms in the 45d5/2 state to the 46d5/2 state, and was used as a probe of interatomic interactions. The spectral width of this two-photon probe transition was found to depend on the presence of the 46p3/2 atoms, and is due to the resonant electric dipole-dipole interaction between 45d5/2 and 46p3/2 Rydberg atoms.

  16. Electric dipole transitions between Gamow-Teller and spin-dipole states

    SciTech Connect

    Suzuki, T.; Sagawa, H.; Van Giai, N.

    1998-01-01

    We study electric dipole transitions between Gamow-Teller (GT) and spin-dipole (SD) states. SD and GT excitations are calculated within the Hartree-Fock+Tamm-Dancoff approximation for {sup 48}Sc and {sup 90}Nb. The electric dipole transitions are found to be rather selective, and strong E1 transitions occur to some specific spin-dipole states. Calculated E1 transition strengths between GT and SD states are compared with the analytic sum rules within one-particle{endash}one-hole (1p-1h) configuration space and within both 1p-1h and 2p-2h model space. Possible implications for charge-exchange reactions may help to understand the quenching problem of spin excitations. {copyright} {ital 1998} {ital The American Physical Society}

  17. Droplet formation in a Bose-Einstein condensate with strong dipole-dipole interaction

    NASA Astrophysics Data System (ADS)

    Xi, Kui-Tian; Saito, Hiroki

    2016-01-01

    Motivated by the recent experiment [H. Kadau et al., arXiv:1508.05007], we study roton instability and droplet formation in a Bose-Einstein condensate of 164Dy atoms with strong magnetic dipole-dipole interaction. We numerically solve the cubic-quintic Gross-Pitaevskii equation with dipole-dipole interaction, and show that the three-body interaction plays a significant role in the formation of droplet patterns. We numerically demonstrate the formation of droplet patterns and crystalline structures, decay of droplets, and hysteresis behavior, which are in good agreement with the experiment. Our numerical simulations provide the first prediction on the values of the three-body interaction in a 164Dy Bose-Einstein condensate. We also predict that the droplets remain stable during the time-of-flight expansion. From our results, further experiments investigating the three-body interaction in dipolar quantum gases are required.

  18. Master equation with quantized atomic motion including dipole-dipole interactions

    NASA Astrophysics Data System (ADS)

    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.

  19. Investigation of the Dipole Response in Exotic Nuclei --- Experiments at the LAND-R^3B Setup

    NASA Astrophysics Data System (ADS)

    Rossi, D.; Adrich, P.; Aksouh, F.; Alvarez-Pol, H.; Aumann, T.; Benlliure, J.; Böhmer, M.; Boretzky, K.; Casarejos, E.; Chartier, M.; Chatillon, A.; Cortina-Gil, D.; Pramanik, U. D.; Emling, H.; Ershova, O.; Fernando-Dominguez, B.; Geissel, H.; Gorska, M.; Heil, M.; Johansson, H. k.; Junghans, A.; Kiselev, O.; Klimkiewicz, A.; Kratz, J.; Kurz, N.; Labiche, M.; Bleis, T. L.; Lemmon, R.; Litvinov, Y.; Mahata, K.; Maierbeck, P.; Movsesyan, A.; Nilsson, T.; Nociforo, C.; Palit, R.; Paschalis, S.; Plag, R.; Reifarth, R.; Simon, H.; Sümmerer, K.; Wagner, A.; Walus, W.; Weick, H.; Winkler, M.

    We present experimental results on the electromagneticexcitation of neutron-rich nickel isotopes, making use of the R^{3}B-LAND setup at GSI. Exotic beams were produced at approximately 500 MeV/u and their reactions were studied in inverse kinematics. Integral cross sections for ^{58}Ni are discussed and compared to previous data, providing a validation of our experimental method. The E1 excitation-energy distribution of the unstable ^{68}Ni is presented as well, showing an excess in cross section in the 1n decay channel when compared only with a typical Giant Dipole Resonance.

  20. Laboratory study of vortex dipoles interacting with step topography

    NASA Astrophysics Data System (ADS)

    Hinds, A. K.; Eames, I.; Johnson, E. R.; McDonald, N. R.

    2009-06-01

    Laboratory experiments are performed which study the behavior of two-dimensional vortex dipoles propagating toward a rectilinear step change in depth. The dipoles are formed in a homogeneous shallow water layer by an impulsive jet and approach the step from either relatively deep or shallow water at normal or oblique incidence. Qualitative observations agree well with previous theoretical predictions: At normal incidence the separation of the two vortices forming the dipole increases for a dipole crossing from deep water and decreases for a dipole crossing from shallow water. Dipoles with oblique angles of incidence refract toward the normal when passing into shallower water, and dipoles that cross the step into deep water refract away from the normal. Dipoles approaching from shallow water at sufficiently large angles of incidence reflect off the step.

  1. Probing dipole-dipole interaction in a rubidium gas via double-quantum 2D spectroscopy.

    PubMed

    Gao, Feng; Cundiff, Steven T; Li, Hebin

    2016-07-01

    We have implemented double-quantum 2D spectroscopy on a rubidium vapor and shown that this technique provides sensitive and background-free detection of the dipole-dipole interaction. The 2D spectra include signals from both individual atoms and interatomic interactions, allowing quantitative studies of the interaction. A theoretical model based on the optical Bloch equations is used to reproduce the experimental spectrum and confirm the origin of double-quantum signals. PMID:27367074

  2. Formation of giant planets

    NASA Astrophysics Data System (ADS)

    Magni, G.; Coradini, A.

    2003-04-01

    In this presentation we address the problem of the formation of giant planets and their regular satellites. We study in particular the problem of formation of the Jupiter System comparing the results of the model with the present characteristics of the system, in order to identify what are those better represented by our approach. In fact here, using a 3-D hydro-dynamical code, we study the modalities of gas accretion onto a solid core, believed to be the seed from which Jupiter started. To do that we have modelled three main regions: the central planet, a turbulent accretion disk surrounding it and an extended region from which the gas is collected. In the extended region we treat the gas as a frictionless fluid. Our main goal is to identify what are the characteristics of the planet during its growth and the physical parameters affecting its growth at the expenses of the nebular gas present in the feeding zone. Moreover we want to understand what are the thermodynamical parameters characterizing the gas captured by the planet and swirling around it. Finally, we check if a disk can be formed in prograde rotation around the planet and if this disk can survive the final phases of the planet formation. Due to the interaction between the accreting planet and the disk it has been necessary to develop a complete model of the Jupiter’s structure. In fact the radiation emitted by the growing planet heats up the surrounding gas. In turn the planet’s thermodynamic structure depend on the mass accretion rate onto it. When the accretion is rapid, shock waves in the gas are formed close to the planet. This region cannot be safely treated by a numerical code; for this reason we have developed a semi-analytically model of a a turbulent accretion disk to be considered as transition between the planet and the surrounding disk.

  3. Rotation of Giant Stars

    NASA Astrophysics Data System (ADS)

    Kissin, Yevgeni; Thompson, Christopher

    2015-07-01

    The internal rotation of post-main sequence stars is investigated, in response to the convective pumping of angular momentum toward the stellar core, combined with a tight magnetic coupling between core and envelope. The spin evolution is calculated using model stars of initial mass 1, 1.5, and 5 {M}⊙ , taking into account mass loss on the giant branches. We also include the deposition of orbital angular momentum from a sub-stellar companion, as influenced by tidal drag along with the excitation of orbital eccentricity by a fluctuating gravitational quadrupole moment. A range of angular velocity profiles {{Ω }}(r) is considered in the envelope, extending from solid rotation to constant specific angular momentum. We focus on the backreaction of the Coriolis force, and the threshold for dynamo action in the inner envelope. Quantitative agreement with measurements of core rotation in subgiants and post-He core flash stars by Kepler is obtained with a two-layer angular velocity profile: uniform specific angular momentum where the Coriolis parameter {Co}\\equiv {{Ω }}{τ }{con}≲ 1 (here {τ }{con} is the convective time), and {{Ω }}(r)\\propto {r}-1 where {Co}≳ 1. The inner profile is interpreted in terms of a balance between the Coriolis force and angular pressure gradients driven by radially extended convective plumes. Inward angular momentum pumping reduces the surface rotation of subgiants, and the need for a rejuvenated magnetic wind torque. The co-evolution of internal magnetic fields and rotation is considered in Kissin & Thompson, along with the breaking of the rotational coupling between core and envelope due to heavy mass loss.

  4. Mutual impedance of nonplanar-skew sinusoidal dipoles

    NASA Technical Reports Server (NTRS)

    Richmond, J. H.; Geary, N. H.

    1974-01-01

    The mutual impedance of nonplanar-skew sinusoidal dipoles is presented as a summation of several exponential integrals with complex arguments. Mathematical models are developed to show the near-zone field of the sinusoidal dipole. The mutual impedance of coupled dipoles is expressed as the sum of four monopole-mobopole impedances to simplify the analysis procedure. The subroutines for solving the parameters of the dipoles are discussed.

  5. Giant lobelias exemplify convergent evolution

    PubMed Central

    2010-01-01

    Giant lobeliads on tropical mountains in East Africa and Hawaii have highly unusual, giant-rosette growth forms that appear to be convergent on each other and on those of several independently evolved groups of Asteraceae and other families. A recent phylogenetic analysis by Antonelli, based on sequencing the widest selection of lobeliads to date, raises doubts about this paradigmatic example of convergent evolution. Here I address the kinds of evidence needed to test for convergent evolution and argue that the analysis by Antonelli fails on four points. Antonelli's analysis makes several important contributions to our understanding of lobeliad evolution and geographic spread, but his claim regarding convergence appears to be invalid. Giant lobeliads in Hawaii and Africa represent paradigmatic examples of convergent evolution. PMID:20074322

  6. CMB lensing and giant rings

    NASA Astrophysics Data System (ADS)

    Rathaus, Ben; Itzhaki, Nissan

    2012-05-01

    We study the CMB lensing signature of a pre-inationary particle (PIP), assuming it is responsible for the giant rings anomaly that was found recently in the WMAP data. Simulating Planck-like data we find that generically the CMB lensing signal to noise ratio associated with such a PIP is quite small and it would be difficult to cross correlate the temperature giant rings with the CMB lensing signal. However, if the pre-inationary particle is also responsible for the bulk flow measured from the local large scale structure, which happens to point roughly at the same direction as the giant rings, then the CMB lensing signal to noise ratio is fairly significant.

  7. Giant myoma and erythrocytosis syndrome.

    PubMed

    Ozsaran, A A; Itil, I M; Terek, C; Kazandi, M; Dikmen, Y

    1999-08-01

    The objective of this study is to discuss the myomatous erythrocytosis syndrome in a patient with a giant subserous uterine myoma. She presented with plethora and an abdominal mass. After venesection of 4 units of blood, the preoperative haematocrit value of 53.3% and haemoglobin value of 17.5 g/dL had decreased to 48.6% and 16.8 g/dL levels, respectively. After the operative extraction of the giant subserous myoma with attached uterus weighing 14.2 kg, the haematocrit and the haemoglobin values had regressed to 40.3% and 14.3 g/dL levels, respectively. The findings indicated that the giant subserous myoma was the cause of the myomatous erythrocytosis syndrome in this patient. PMID:10554963

  8. Structure of giant muscle proteins

    PubMed Central

    Meyer, Logan C.; Wright, Nathan T.

    2013-01-01

    Giant muscle proteins (e.g., titin, nebulin, and obscurin) play a seminal role in muscle elasticity, stretch response, and sarcomeric organization. Each giant protein consists of multiple tandem structural domains, usually arranged in a modular fashion spanning 500 kDa to 4 MDa. Although many of the domains are similar in structure, subtle differences create a unique function of each domain. Recent high and low resolution structural and dynamic studies now suggest more nuanced overall protein structures than previously realized. These findings show that atomic structure, interactions between tandem domains, and intrasarcomeric environment all influence the shape, motion, and therefore function of giant proteins. In this article we will review the current understanding of titin, obscurin, and nebulin structure, from the atomic level through the molecular level. PMID:24376425

  9. Peripheral Giant Cell Granuloma in a Dog.

    PubMed

    Hiscox, Lorraine A; Dumais, Yvan

    2015-01-01

    Peripheral giant cell granuloma is considered rare in the dog with little known about the clinicopathologic features. There are few reports in the veterinary literature concerning this benign, reactive lesion, formerly known as giant cell epulis. In humans, the four most commonly described reactive epulides are focal fibrous hyperplasia (fibrous epulis), pyogenic granuloma, peripheral ossifying fibroma, and peripheral giant cell granuloma. This case report describes the diagnosis and surgical management of a peripheral giant cell granuloma in a dog. PMID:26415387

  10. Giant axonal neuropathy: MRS findings.

    PubMed

    Alkan, Alpay; Kutlu, Ramazan; Sigirci, Ahmet; Baysal, Tamer; Altinok, Tayfun; Yakinci, Cengiz

    2003-10-01

    Giant axonal neuropathy (GAN) is a rare genetic disease of childhood involving the central and peripheral nervous systems. Axonal loss with several giant axons filled with neurofilaments is the main histopathological feature of peripheral nerve biopsies in this disease. Routine neuroimaging studies reveal diffuse hyperintensities in cerebral and cerebellar white matter. In this case report, the authors present the brain magnetic resonance spectroscopic features (normal N-acetylaspartate/creatine and increased choline/creatine and myoinositol/creatine ratios), which might indicate the absence of neuroaxonal loss and the presence of significant demyelination and glial proliferation in white matter, of an 11-year-old boy diagnosed with GAN. PMID:14569833

  11. Chemical Abundances of Symbiotic Giants

    NASA Astrophysics Data System (ADS)

    Gałan, C.; Mikołajewska, J.; Hinkle, K. H.; Joyce, R. R.

    2015-12-01

    High resolution (R ˜ 50000), near-IR spectra were used to measure photospheric abundances of CNO and elements around the iron peak for 24 symbiotic giants. Spectrum synthesis was employed using local thermal equilibrium and hydrostatic model atmospheres. The metallicities are distributed in a wide range with maximum around [Fe/H] ˜-0.4 - - 0.3 dex. Enrichment in 14N indicates that all the sample giants have experienced the first dredge-up. The relative abundance of [Ti/Fe] is generally large in red symbiotic systems.

  12. Charting the Giants

    NASA Astrophysics Data System (ADS)

    2004-06-01

    zero expansion asymptotically after an infinite time and has a flat geometry). All three observational tests by means of supernovae (green), the cosmic microwave background (blue) and galaxy clusters converge at a Universe around Ωm ~ 0.3 and ΩΛ ~ 0.7. The dark red region for the galaxy cluster determination corresponds to 95% certainty (2-sigma statistical deviation) when assuming good knowledge of all other cosmological parameters, and the light red region assumes a minimum knowledge. For the supernovae and WMAP results, the inner and outer regions corespond to 68% (1-sigma) and 95% certainty, respectively. References: Schuecker et al. 2003, A&A, 398, 867 (REFLEX); Tonry et al. 2003, ApJ, 594, 1 (supernovae); Riess et al. 2004, ApJ, 607, 665 (supernovae) Galaxy clusters are far from being evenly distributed in the Universe. Instead, they tend to conglomerate into even larger structures, "super-clusters". Thus, from stars which gather in galaxies, galaxies which congregate in clusters and clusters tying together in super-clusters, the Universe shows structuring on all scales, from the smallest to the largest ones. This is a relict of the very early (formation) epoch of the Universe, the so-called "inflationary" period. At that time, only a minuscule fraction of one second after the Big Bang, the tiny density fluctuations were amplified and over the eons, they gave birth to the much larger structures. Because of the link between the first fluctuations and the giant structures now observed, the unique REFLEX catalogue - the largest of its kind - allows astronomers to put considerable constraints on the content of the Universe, and in particular on the amount of dark matter that is believed to pervade it. Rather interestingly, these constraints are totally independent from all other methods so far used to assert the existence of dark matter, such as the study of very distant supernovae (see e.g. ESO PR 21/98) or the analysis of the Cosmic Microwave background (e

  13. Simulation of an Ice Giant-style Dynamo

    NASA Astrophysics Data System (ADS)

    Soderlund, K. M.; Aurnou, J. M.

    2010-12-01

    The Ice Giants, Uranus and Neptune, are unique in the solar system. These planets are the only known bodies to have multipolar magnetic fields where the quadrupole and octopole components have strengths comparable to or greater than that of the dipole. Cloud layer observations show that the planets also have zonal (east-west) flows that are fundamentally different from the banded winds of Jupiter and Saturn. The surface winds are characterized by strong retrograde equatorial jets that are flanked on either side by prograde jets at high latitudes. Thermal emission measurements of Neptune show that the surface energy flux pattern peaks in the equatorial and polar regions with minima at mid-latitudes. (The measurements for Uranus cannot adequately resolve the emission pattern.) The winds and magnetic fields are thought to be the result of convection in the planetary interior, which will also affect the heat flux pattern. Typically, it is implicitly assumed that the zonal winds are generated in a shallow layer, separate from the dynamo generation region. However, if the magnetic fields are driven near the surface, a single region can simultaneously generate both the zonal flows and the magnetic fields. Here, we present a novel numerical model of an Ice Giant-style dynamo to investigate this possibility. An order unity convective Rossby number (ratio of buoyancy to Coriolis forces) has been chosen because retrograde equatorial jets tend to occur in spherical shells when the effects of rotation are relatively weak. Our modeling results qualitatively reproduce all of the structural features of the global dynamical observations. Thus, a self-consistent model can generate magnetic field, zonal flow, and thermal emission patterns that agree with those of Uranus and Neptune. This model, then, leads us to hypothesize that the Ice Giants' zonal flows and magnetic fields are generated via dynamically coupled deep convection processes.

  14. Transverse current on strip dipole antenna

    NASA Astrophysics Data System (ADS)

    Wunsch, A. D.

    1982-07-01

    Analyses of the current of thin wire dipole antennas presuppose that the current is parallel to the antenna axis. It is pointed out that a component of current transverse to the antenna axis can exist for antennas having a noncircular cross section, such as the strip dipole. The present investigation is concerned with a perfectly conducting strip antenna which is center driven by a delta function generator, taking into account the surface current-density components Kx(x,z) and Kz(x,z). In the solution of the resulting integral equations, it is assumed that Kz is considerably stronger than the transverse surface current density Kx. After obtaining an approximation to Kz, the second integral equation is solved for Kx. Results for the normalized transverse surface current density are presented in graphs.

  15. RHIC AC DIPOLE DESIGN AND CONSTRUCTION.

    SciTech Connect

    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.

  16. Generation of squeezing: magnetic dipoles on cantilevers

    NASA Astrophysics Data System (ADS)

    Seok, Hyojun; Singh, Swati; Steinke, Steven; Meystre, Pierre

    2011-05-01

    We investigate the generation of motional squeezed states in a nano-mechanical cantilever. Our model system consists of a nanoscale cantilever - whose center-of-mass motion is initially cooled to its quantum mechanical ground state - magnetically coupled a classically driven mechanical tuning fork. We show that the magnetic dipole-dipole interaction can produce significant phonon squeezing of the center-of-mass motion of the cantilever, and evaluate the effect of various dissipation channels, including the coupling of the cantilever to a heat bath and phase and amplitude fluctuations in the oscillating field driving the tuning fork. US National Science Foundation, the US Army Research Office, DARPA ORCHID program through a grant from AFOSR.

  17. Dynamical dipole mode in fusion reactions

    SciTech Connect

    Pierroutsakou, D.; Boiano, A.; Romoli, M.; Martin, B.; Inglima, G.; La Commara, M.; Sandoli, M.; Agodi, C.; Alba, R.; Coniglione, R.; Zoppo, A. Del; Maiolino, C.; Piattelli, P.; Santonocito, D.; Sapienza, P.; Baran, V.; Glodariu, T.; Cardella, G.; De Filippo, E.; Pagano, A.

    2009-05-04

    We investigated the dynamical dipole mode, related with entrance channel charge asymmetry effects, in the {sup 40}Ar+{sup 92}Zr and {sup 36}Ar+{sup 96}Zr fusion reactions at E{sub lab} = 15.1 A and 16 A MeV, respectively. These reactions populate, through entrance channels having different charge asymmetries, a compound nucleus in the A = 126 mass energy region, identical spin distribution at an average excitation energy of about 280 MeV. The compound nucleus average excitation energy and average mass were deduced by the analysis of the light charged particle energy spectra. By studying the {gamma}-ray energy spectra and the {gamma}-ray angular distributions of the considered reactions, the dynamical nature of the prompt radiation related to the dynamical dipole mode was evidenced. The data are compared with calculations based on a collective bremsstrahlung analysis of the reaction dynamics.

  18. Revisiting the NVSS number count dipole

    NASA Astrophysics Data System (ADS)

    Tiwari, Prabhakar; Nusser, Adi

    2016-03-01

    We present a realistic modeling of the dipole component of the projected sky distribution of NVSS radio galaxies. The modeling relies on mock catalogs generated within the context of ΛCDM cosmology, in the linear regime of structure formation. After removing the contribution from the solar motion, the mocks show that the remaining observed signal is mostly (70%) due to structures within z lesssim 0.1. The amplitude of the model signal depends on the bias factor b of the NVSS mock galaxies. For sources with flux density, S > 15 mJy, the bias recipe inferred from higher order moments is consistent with the observed dipole signal at 2.12σ. Flux thresholds above 20 mJy yield a disagreement close to the 3σ level. A constant high bias, b = 3 is needed to mitigate the tension to the ~ 2.3σ level.

  19. Search for the electron electric dipole moment

    SciTech Connect

    De Mille, D.; Bickman, S.; Hamilton, P.; Jiang, Y.; Prasad, V.; Kawall, D.; Paolino, R.

    2006-07-11

    Extensions to the Standard Model (SM) typically include new heavy particles and new mechanisms for CP violation. These underlying phenomena can give rise to electric dipole moments of the electron and other particles. Tabletop-scale experiments used to search for these effects are described. Present experiments are already sensitive to new physics at the TeV scale, and new methods could extend this range dramatically. Such experiments could be among the first to show evidence for physics beyond the SM.

  20. 15 T And Beyond - Dipoles and Quadrupoles

    SciTech Connect

    Sabbi, GianLuca

    2008-05-19

    Starting with the invention of the cyclotron by Lawrence, accelerator-based experiments have been the primary source of new discoveries in particle physics. In order to progress toward higher energy and luminosity, higher field magnets are required. R&D programs are underway to take advantage of new developments in superconducting materials, achieve better efficiency and simplify magnet fabrication while preserving accelerator-class field quality. A review of recent progress on high field dipole and quadrupole magnets is presented.

  1. Magnetic field modification of optical magnetic dipoles.

    PubMed

    Armelles, Gaspar; Caballero, Blanca; Cebollada, Alfonso; Garcia-Martin, Antonio; Meneses-Rodríguez, David

    2015-03-11

    Acting on optical magnetic dipoles opens novel routes to govern light-matter interaction. We demonstrate magnetic field modification of the magnetic dipolar moment characteristic of resonant nanoholes in thin magnetoplasmonic films. This is experimentally shown through the demonstration of the magneto-optical analogue of Babinet's principle, where mirror imaged MO spectral dependencies are obtained for two complementary magnetoplasmonic systems: holes in a perforated metallic layer and a layer of disks on a substrate. PMID:25646869

  2. Black Saturn with a dipole ring

    SciTech Connect

    Yazadjiev, Stoytcho S.

    2007-09-15

    We present a new stationary, asymptotically flat solution of 5D Einstein-Maxwell gravity describing a Saturn-like black object: a rotating black hole surrounded by a rotating dipole black ring. The solution is generated by combining the vacuum black Saturn solution and the vacuum black ring solution with appropriately chosen parameters. Some basic properties of the solution are analyzed and the basic quantities are calculated.

  3. Toroidal Dipole Moment of a Massless Neutrino

    SciTech Connect

    Cabral-Rosetti, L. G.; Mondragon, M.; Perez, E. Reyes

    2009-04-20

    We obtain the toroidal dipole moment of a massless neutrino {tau}{sub v{sub I}}{sup M} using the results for the anapole moment of a massless Dirac neutrino a{sub v{sub I}}{sup D}, which was obtained in the context of the Standard Model of the electroweak interactions (SM)SU(2){sub L} x U(1){sub Y}.

  4. Electric dipole moment of light nuclei

    SciTech Connect

    Gibson, Benjamin; Afnan, I R

    2010-01-01

    We examine the sensitivity of the deuteron Electric Dipole Moment (EDM) to variation in the nucleon-nucleon interaction. In particular, we write the EDM as a sum of two terms, one depends on the target wave function, the second on intermediate multiple scattering states in the {sup 3}P{sub 1} channel. This second contribution is sensitive to off-shell behavior of the {sup 3}P{sub 1} amplitude.

  5. Electric dipole moment of light nuclei

    SciTech Connect

    Afnan, Iraj R.; Gibson, Benjamin F.

    2010-07-27

    We examine the sensitivity of the deuteron Electric Dipole Moment (EDM) to variation in the nucleon-nucleon interaction. In particular, we write the EDM as a sum of two terms, one depends on the target wave function, the second on intermediate multiple scattering states in the {sup 3}P{sub 1} channel. This second contribution is sensitive to off-shell behavior of the {sup 3}P{sub 1} amplitude.

  6. The midpoint between dipole and parton showers

    NASA Astrophysics Data System (ADS)

    Höche, Stefan; Prestel, Stefan

    2015-09-01

    We present a new parton-shower algorithm. Borrowing from the basic ideas of dipole cascades, the evolution variable is judiciously chosen as the transverse momentum in the soft limit. This leads to a very simple analytic structure of the evolution. A weighting algorithm is implemented that allows one to consistently treat potentially negative values of the splitting functions and the parton distributions. We provide two independent, publicly available implementations for the two event generators P ythia and S herpa.

  7. The midpoint between dipole and parton showers

    SciTech Connect

    Höche, Stefan; Prestel, Stefan

    2015-09-28

    We present a new parton-shower algorithm. Borrowing from the basic ideas of dipole cascades, the evolution variable is judiciously chosen as the transverse momentum in the soft limit. This leads to a very simple analytic structure of the evolution. A weighting algorithm is implemented that allows one to consistently treat potentially negative values of the splitting functions and the parton distributions. Thus, we provide two independent, publicly available implementations for the two event generators PYTHIA and SHERPA.

  8. Trapped field internal dipole superconducting motor generator

    DOEpatents

    Hull, John R.

    2001-01-01

    A motor generator including a high temperature superconductor rotor and an internally disposed coil assembly. The motor generator superconductor rotor is constructed of a plurality of superconductor elements magnetized to produce a dipole field. The coil assembly can be either a conventional conductor or a high temperature superconductor. The superconductor rotor elements include a magnetization direction and c-axis for the crystals of the elements and which is oriented along the magnetization direction.

  9. Characterizing single atom optical dipole traps

    NASA Astrophysics Data System (ADS)

    Shih, Chung-Yu; Gibbons, Michael; Chapman, Michael

    2012-06-01

    Trapping and manipulating individual neutral atoms in far off-resonant traps (FORTs) is a promising approach for quantum information processing. It is important to characterize the trapping environment of the atom and the atomic level shifts due to the trapping fields. Using non-destructive measurement techniques,ootnotetextM. J. Gibbons et al., Phys. Rev. Lett 106, 133002 (2011). we have measured the level dependent AC Stark shifts, trap frequencies, and temperature of single rubidium atoms confined in optical dipole trap.

  10. Giant perpendicular magnetocrystalline anisotropy of 3d transition-metal thin films on MgO

    SciTech Connect

    Nakamura, Kohji Ikeura, Yushi; Akiyama, Toru; Ito, Tomonori

    2015-05-07

    Magnetocrystalline anisotropy (MCA) of the Fe-based transition-metal thin films was investigated by means of first principles full-potential linearized augmented plane wave method. A giant perpendicular MCA (PMCA), up to 3 meV, was confirmed in a 7-layer Fe-Ni film/MgO(001), where an Fe{sub 2}/Ni/Fe/Ni/Fe{sub 2} atomic-layer alignment with a bcc-like-layer stacking and the Fe/MgO interfaces play key roles for leading to the large PMCA. Importantly, we find that the PMCA overcomes enough over the magnetic dipole-dipole anisotropy that favors the in-plane magnetization even when the film thickness increases.

  11. Soft dipole excitations in 11Li

    NASA Astrophysics Data System (ADS)

    Esbensen, H.; Bertsch, G. F.

    1992-06-01

    A three-body model of 11Li is extended to include all interactions in unbound states in the continuum. We use a Green function technique to solve the three-body hamiltonian equation, and study the continuum dipole states produced by electromagnetic excitations of the ground state. The final-state interaction modifies the dipole strength function substantially, making it similar to an independent-particle strength function, but the total strength is enhanced by 50% due to ground-state correlations. The dipole strength is concentrated in a peak just above threshold, and the strength distribution is consistent with the measured beam energy dependence of the Coulomb dissociation cross section. This threshold peak also gives a narrow component in the neutron and the residual nucleus momentum distributions. The angular distributions of the neutrons emitted in Coulomb-induced reactions show a surprising anticorrelation, favoring emission with a large opening angle between the directions of the two neutrons in the rest frame of 11Li.

  12. Bent Solenoids with Superimposed Dipole Fields

    SciTech Connect

    Meinke, Rainer, B.; Goodzeit, Carl, L.

    2000-03-21

    A conceptual design and manufacturing technique were developed for a superconducting bent solenoid magnet with a superimposed dipole field that would be used as a dispersion device in the cooling channel of a future Muon Collider. The considered bent solenoid is equivalent to a 180° section of a toroid with a major radius of ~610 mm and a coil aperture of ~416 mm. The required field components of this magnet are 4 tesla for the solenoid field and 1 tesla for the superimposed dipole field. A magnet of this size and shape, operating at these field levels, has to sustain large Lorentz forces resulting in a maximum magnetic pressure of about 2,000 psi. A flexible round mini-cable with 37 strands of Cu-NbTi was selected as the superconductor. Detailed magnetic analysis showed that it is possible to obtain the required superimposed dipole field by tilting the winding planes of the solenoid by ~25°. A complete structural analysis of the coil support system and the helium containment vessel under thermal, pressure, and Lorentz force loads was carried out using 3D finite element models of the structures. The main technical issues were studied and solutions were worked out so that a highly reliable magnet of this type can be produced at an affordable cost.

  13. Pygmy dipole strength in Zr90

    NASA Astrophysics Data System (ADS)

    Schwengner, R.; Rusev, G.; Tsoneva, N.; Benouaret, N.; Beyer, R.; Erhard, M.; Grosse, E.; Junghans, A. R.; Klug, J.; Kosev, K.; Lenske, H.; Nair, C.; Schilling, K. D.; Wagner, A.

    2008-12-01

    The dipole response of the N=50 nucleus Zr90 was studied in photon-scattering experiments at the electron linear accelerator ELBE with bremsstrahlung produced at kinetic electron energies of 7.9, 9.0, and 13.2 MeV. We identified 189 levels up to an excitation energy of 12.9 MeV. Statistical methods were applied to estimate intensities of inelastic transitions and to correct the intensities of the ground-state transitions for their branching ratios. In this way we derived the photoabsorption cross section up to the neutron-separation energy. This cross section matches well the photoabsorption cross section obtained from (γ, n) data and thus provides information about the extension of the dipole-strength distribution toward energies below the neutron-separation energy. An enhancement of E1 strength has been found in the range of 6 to 11 MeV. Calculations within the framework of the quasiparticle-phonon model ascribe this strength to a vibration of the excessive neutrons against the N=Z neutron-proton core, giving rise to a pygmy dipole resonance.

  14. Local electric dipole moments: A generalized approach.

    PubMed

    Groß, Lynn; Herrmann, Carmen

    2016-09-30

    We present an approach for calculating local electric dipole moments for fragments of molecular or supramolecular systems. This is important for understanding chemical gating and solvent effects in nanoelectronics, atomic force microscopy, and intensities in infrared spectroscopy. Owing to the nonzero partial charge of most fragments, "naively" defined local dipole moments are origin-dependent. Inspired by previous work based on Bader's atoms-in-molecules (AIM) partitioning, we derive a definition of fragment dipole moments which achieves origin-independence by relying on internal reference points. Instead of bond critical points (BCPs) as in existing approaches, we use as few reference points as possible, which are located between the fragment and the remainder(s) of the system and may be chosen based on chemical intuition. This allows our approach to be used with AIM implementations that circumvent the calculation of critical points for reasons of computational efficiency, for cases where no BCPs are found due to large interfragment distances, and with local partitioning schemes other than AIM which do not provide BCPs. It is applicable to both covalently and noncovalently bound systems. © 2016 Wiley Periodicals, Inc. PMID:27520590

  15. Radiation Q of dipole-generated fields

    NASA Astrophysics Data System (ADS)

    Grimes, Dale M.; Grimes, Craig A.

    1999-03-01

    The radiation Q of several dipole fields in free space are determined using the time-dependent Poynting theorem. Earlier works on this subject, recently summarized by McLean [1996], are based upon the complex Poynting theorem. It was previously shown [Grimes and Grimes, 1997] that the full complex Poynting theorem is correct only for single-mode radiation fields. The time-dependent theorem shows that three numbers are necessary to completely specify time-varying power, and complex numbers supply but two; the third piece of information, a phase, is discarded when complex notation is formed. Omissions inherent in the complex Poynting theorem affect the calculated value of standing energy about an antenna and hence the calculated value of Q. To avoid such omissions, we develop a method of determining Q based upon the time-dependent Poynting theorem that builds upon and extends our earlier work [Grimes and Grimes, 1997]. The purposes of this paper are to (1) provide a time domain basis for calculating Q in mixed modal radiation fields, (2) determine the Q of electric and magnetic dipoles, alone and in combination, and (3) demonstrate how source structure and relative phasing affect the physics of several combinations of electric and magnetic dipole radiation fields. The primary conclusion of this work is that the minimum possible Q of a radiation source established by Chu [1948] does not extend to properly mixed and phased multimodal radiation fields. A radiation source is presented for which, by our analysis, the radiation Q is zero.

  16. Dynamics of two-dimensional dipole systems

    SciTech Connect

    Golden, Kenneth I.; Kalman, Gabor J.; Hartmann, Peter; Donko, Zoltan

    2010-09-15

    Using a combined analytical/molecular dynamics approach, we study the current fluctuation spectra and longitudinal and transverse collective mode dispersions of the classical two-dimensional (point) dipole system (2DDS) characterized by the {phi}{sub D}(r)={mu}{sup 2}/r{sup 3} repulsive interaction potential; {mu} is the electric dipole strength. The interest in the 2DDS is twofold. First, the quasi-long-range 1/r{sup 3} interaction makes the system a unique classical many-body system, with a remarkable collective mode behavior. Second, the system may be a good model for a closely spaced semiconductor electron-hole bilayer, a system that is in the forefront of current experimental interest. The longitudinal collective excitations, which are of primary interest for the liquid phase, are acoustic at long wavelengths. At higher wave numbers and for sufficiently high coupling strength, we observe the formation of a deep minimum in the dispersion curve preceded by a sharp maximum; this is identical to what has been observed in the dispersion of the zero-temperature bosonic dipole system, which in turn emulates so-called roton-maxon excitation spectrum of the superfluid {sup 4}He. The analysis we present gives an insight into the emergence of this apparently universal structure, governed by strong correlations. We study both the liquid and the crystalline solid state. We also observe the excitation of combination frequencies, resembling the roton-roton, roton-maxon, etc. structures in {sup 4}He.

  17. The giant panda gut microbiome.

    PubMed

    Wei, Fuwen; Wang, Xiao; Wu, Qi

    2015-08-01

    Giant pandas (Ailuropoda melanoleuca) are bamboo specialists that evolved from carnivores. Their gut microbiota probably aids in the digestion of cellulose and this is considered an example of gut microbiota adaptation to a bamboo diet. However, this issue remains unresolved and further functional and compositional studies are needed. PMID:26143242

  18. Giant Serpentine Aneurysms: Multidisciplinary Management

    PubMed Central

    Anshun, W.; Feng, L.; Daming, W.

    2000-01-01

    Summary Sixty-five cases of intracranial giant serpentine aneurysms (GSΛs), including 61 cases reported in the literature and four additional cases presented in this study were reviewed. The clinical presentation, possible causes, natural history, and especially management of GSAs are discussed with emphasis on the need for aggressive intervention and multidisciplinary management. PMID:20667180

  19. Molecular Line and Continuum Opacities for Modeling of Extrasolar Giant Planet and Cool Stellar Atmospheres

    NASA Technical Reports Server (NTRS)

    Weck, P. F.; Schweitzer, A.; Stancil, P. C.; Hauschildt, P. H.; Kirby, K.; Yamaguchi, Y.; Allen, W. D.

    2002-01-01

    The molecular line and continuum opacities are investigated in the atmospheres of cool stars and Extrasolar Giant Planets (EGPs). Using a combination of ab inito and experimentally derived potential curves and dipole transition moments, accurate data have been calculated for rovibrationally-resolved oscillator strengths and photodissociation cross sections in the B' (sup 2)Sigma+ (left arrow) X (sup 2)Sigma+ and A (sup 2)Pi (left arrow) X (sup 2)Sigma+ band systems in MgH. We also report our progress on the study of the electronic structure of LiCl and FeH.

  20. Experimental study of the electric dipole strength in the even Mo nuclei and its deformation dependence

    NASA Astrophysics Data System (ADS)

    Erhard, M.; Junghans, A. R.; Nair, C.; Schwengner, R.; Beyer, R.; Klug, J.; Kosev, K.; Wagner, A.; Grosse, E.

    2010-03-01

    Two methods based on bremsstrahlung were applied to the stable even Mo isotopes for the experimental determination of the photon strength function covering the high excitation energy range above 4 MeV with its increasing level density. Photon scattering was used up to the neutron separation energies Sn and data up to the maximum of the isovector giant resonance (GDR) were obtained by photoactivation. After a proper correction for multistep processes the observed quasicontinuous spectra of scattered photons show a remarkably good match to the photon strengths derived from nuclear photoeffect data obtained previously by neutron detection and corrected in absolute scale by using the new activation results. The combined data form an excellent basis to derive a shape dependence of the E1 strength in the even Mo isotopes with increasing deviation from the N=50 neutron shell (i.e., with the impact of quadrupole deformation and triaxiality). The wide energy coverage of the data allows for a stringent assessment of the dipole sum rule and a test of a novel parametrization developed previously which is based on it. This parametrization for the electric dipole strength function in nuclei with A>80 deviates significantly from prescriptions generally used previously. In astrophysical network calculations it may help to quantify the role the p-process plays in cosmic nucleosynthesis. It also has impact on the accurate analysis of neutron capture data of importance for future nuclear energy systems and waste transmutation.

  1. Spatially Resolved Observation of Dipole-Dipole Interaction between Rydberg Atoms

    SciTech Connect

    Ditzhuijzen, C. S. E. van; Noordam, L. D.; Heuvell, H. B. van Linden van den; Koenderink, A. F.; Hernandez, J. V.; Robicheaux, F.

    2008-06-20

    We have observed resonant energy transfer between cold Rydberg atoms in spatially separated cylinders. Resonant dipole-dipole coupling excites the 49s atoms in one cylinder to the 49p state while the 41d atoms in the second cylinder are transferred down to the 42p state. We have measured the production of the 49p state as a function of separation of the cylinders (0-80 {mu}m) and the interaction time (0-25 {mu}s). In addition, we measured the width of the electric field resonances. A full many-body quantum calculation reproduces the main features of the experiments.

  2. Soliton stability and collapse in the discrete nonpolynomial Schroedinger equation with dipole-dipole interactions

    SciTech Connect

    Gligoric, Goran; Hadzievski, Ljupco; Maluckov, Aleksandra; Malomed, Boris A.

    2009-05-15

    The stability and collapse of fundamental unstaggered bright solitons in the discrete Schroedinger equation with the nonpolynomial on-site nonlinearity, which models a nearly one-dimensional Bose-Einstein condensate trapped in a deep optical lattice, are studied in the presence of the long-range dipole-dipole (DD) interactions. The cases of both attractive and repulsive contact and DD interaction are considered. The results are summarized in the form of stability-collapse diagrams in the parametric space of the model, which demonstrate that the attractive DD interactions stabilize the solitons and help to prevent the collapse. Mobility of the discrete solitons is briefly considered too.

  3. Electric dipole moments (EDM) of ionic atoms

    NASA Astrophysics Data System (ADS)

    Oshima, Sachiko

    2010-03-01

    Recent investigations show that the second-order perturbation calculations of electric dipole moments (EDM) from the finite nuclear size as well as the relativistic effects are all canceled out by the third-order perturbation effects and that this is due to electron screening. To derive the nucleon EDM from the nucleus, we propose to measure the EDM of an ionic system. In this case, it is shown that the nucleon EDM can survive by the reduction factor of 1/Z for the ionic system with one electron stripped off.

  4. Revised cross section for RHIC dipole magnets

    SciTech Connect

    Thompson, P.A.; Gupta, R.C.; Kahn, S.A.; Hahn, H.; Morgan, G.H.; Wanderer, P.J.; Willen, E.

    1991-01-01

    Using the experience gained in designing and building Relativistic Heavy Ion Collider (RHIC) dipole prototype magnets an improved cross section has been developed. Significant features of this design include the use of only three wedges for field shaping and wedge cross sections which are sectors of an annulus. To aid in the understanding of the actual magnets, one has been sectioned, and detailed mechanical and photographic measurements made of the wire positions. The comparison of these measurements with the magnetic field measurements will is presented. 2 refs, 3 figs., 2 tabs.

  5. NMR measurements in SSC dipole D00001

    SciTech Connect

    Kuchnir, M.; Schmidt, E.E.; Hanft, R.W.; Strait, J.B.

    1986-09-12

    The first 16.5 m long SSC dipole magnet (D00001) had its field intensity measured as a function of position with a custom made NMR magnetometer. A short description of the probe is presented. The data obtained (most of it near 2 T spaced apart by one inch) shows an average transfer function of 1.02830 T/KA with position dependent values deviating from the average by up to .00130 T/KA revealing contruction inhomogeneities that were measured with a sensitivity of 25 ppM.

  6. Electric dipole moments (EDM) of ionic atoms

    SciTech Connect

    Oshima, Sachiko

    2010-03-15

    Recent investigations show that the second-order perturbation calculations of electric dipole moments (EDM) from the finite nuclear size as well as the relativistic effects are all canceled out by the third-order perturbation effects and that this is due to electron screening. To derive the nucleon EDM from the nucleus, we propose to measure the EDM of an ionic system. In this case, it is shown that the nucleon EDM can survive by the reduction factor of 1/Z for the ionic system with one electron stripped off.

  7. SSC dipole vacuum vessel support placement analysis

    SciTech Connect

    Nicol, T.H.

    1987-08-01

    Early (superconducting super collider) SSC dipole model magnets were supported at five points along their length by feet welded to the vacuum vessel. The cold mass was supported at the same five points. The number of supports was determined such that the maximum cold mass deflection between supports was limited to 0.010 inches as specified in the first version of the SSC Design Criteria. The spacing between supports was determined to minimize the sag of the cold mass, given five supports. This paper analyzes the deflection of the cold mass and vacuum vessel as a result of these supports. 4 refs. (LSP)

  8. Large muon electric dipole moment from flavor?

    SciTech Connect

    Hiller, Gudrun; Huitu, Katri; Rueppell, Timo; Laamanen, Jari

    2010-11-01

    We study the prospects and opportunities of a large muon electric dipole moment (EDM) of the order (10{sup -24}-10{sup -22}) ecm. We investigate how natural such a value is within the general minimal supersymmetric extension of the standard model with CP violation from lepton flavor violation in view of the experimental constraints. In models with hybrid gauge-gravity-mediated supersymmetry breaking, a large muon EDM is indicative for the structure of flavor breaking at the Planck scale, and points towards a high messenger scale.

  9. Multilayer Microstrip Slot And Dipole Array Antenna

    NASA Technical Reports Server (NTRS)

    Tulintseff, Ann N.

    1994-01-01

    Multilayer antenna structure contains interleaved linear subarrays of microstrip dipole and slot radiating antenna elements to provide compact, dual-band antenna. Structure also contains associated microstrip transmission lines, plus high-power amplifiers for transmission and low-noise amplifiers for reception. Overall function is to transmit in horizontal polarization at frequency of 29.634 GHz and receive in vertical polarization at 19.914 GHz, in direction 44 degrees from broadside to antenna. Antenna structure is part of apparatus described in "Steerable K/Ka-band Antenna for Land-Mobile Satellite Applications," NPO-18772.

  10. Toroidal dipole excitations in metamolecules formed by interacting plasmonic nanorods

    NASA Astrophysics Data System (ADS)

    Watson, Derek W.; Jenkins, Stewart D.; Ruostekoski, Janne; Fedotov, Vassili A.; Zheludev, Nikolay I.

    2016-03-01

    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 appears as a Fano resonance dip in the forward scattered light. 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.

  11. Structure and melting behavior of classical bilayer crystals of dipoles

    SciTech Connect

    Lu Xin; Wu Changqin; Micheli, Andrea; Pupillo, Guido

    2008-07-01

    We study the structure and melting of a classical bilayer system of dipoles in a setup where the dipoles are oriented perpendicular to the planes of the layers and the density of dipoles is the same in each layer. Due to the anisotropic character of the dipole-dipole interactions, we find that the ground-state configuration is given by two hexagonal crystals positioned on top of each other, independent of the interlayer spacing and dipolar density. For large interlayer distances these crystals are independent, while in the opposite limit of small interlayer distances the system behaves as a two-dimensional crystal of paired dipoles. Within the harmonic approximation for the phonon excitations, the melting temperature of these crystalline configurations displays a nonmonotonic dependence on the interlayer distance, which is associated with a re-entrant melting behavior in the form of solid-liquid-solid-liquid transitions at fixed temperature.

  12. [Giant intradiploic infratentorial epidermoid cyst].

    PubMed

    Alberione, F; Caire, F; Fischer-Lokou, D; Gueye, M; Moreau, J J

    2007-10-01

    Epidermoid cysts are benign, uncommon lesions (1% of all intracranial tumors). Their localization is intradiploic in 25% of cases, and exceptionally subtentorial. We report here a rare case of giant intradiploic infratentorial epidermoid cyst. A 74-year old patient presented with recent diplopia and sindrome cerebellar. CT scan and MR imaging revealed a giant osteolytic extradural lesion of the posterior fossa (5.2 cm x 3.8 cm) with a small area of peripheral enhancement after contrast injection. Retrosigmoid suboccipital craniectomy allowed a satisfactory removal of the tumor, followed by an acrylic cranioplasty. The outcome was good. Neuropathological examination confirmed an epidermoid cyst. We review the literature and discuss our case. PMID:18008017

  13. Giant viruses come of age.

    PubMed

    Fischer, Matthias G

    2016-06-01

    Viruses with genomes up to a few megabases in length are a common occurrence in nature, even though they have escaped our notice until recently. These giant viruses infect mainly single-celled eukaryotes and isolation efforts concentrating on amoebal hosts alone have spawned hundreds of viral isolates, featuring viruses with previously unseen virion morphologies and the largest known viral genomes and particles. One of the challenges that lie ahead is to analyze and categorize the available data and to establish an approved classification system that reflects the evolutionary relationships and biological properties of these viruses. Extensive sampling of Acanthamoeba-infecting mimiviruses and initial characterization of their virophage parasites have provided a first blueprint of the genetic diversity and composition of a giant virus clade that will facilitate the taxonomic grouping of these fascinating microorganisms. PMID:26999382

  14. Proteorhodopsin genes in giant viruses

    PubMed Central

    2012-01-01

    Viruses with large genomes encode numerous proteins that do not directly participate in virus biogenesis but rather modify key functional systems of infected cells. We report that a distinct group of giant viruses infecting unicellular eukaryotes that includes Organic Lake Phycodnaviruses and Phaeocystis globosa virus encode predicted proteorhodopsins that have not been previously detected in viruses. Search of metagenomic sequence data shows that putative viral proteorhodopsins are extremely abundant in marine environments. Phylogenetic analysis suggests that giant viruses acquired proteorhodopsins via horizontal gene transfer from proteorhodopsin-encoding protists although the actual donor(s) could not be presently identified. The pattern of conservation of the predicted functionally important amino acid residues suggests that viral proteorhodopsin homologs function as sensory rhodopsins. We hypothesize that viral rhodopsins modulate light-dependent signaling, in particular phototaxis, in infected protists. This article was reviewed by Igor B. Zhulin and Laksminarayan M. Iyer. For the full reviews, see the Reviewers’ reports section. PMID:23036091

  15. Propagation of magnetic dipole radiation through a medium.

    PubMed

    Arnoldus, Henk F; Xu, Zhangjin

    2016-05-01

    An oscillating magnetic dipole moment emits radiation. We assume that the dipole is embedded in a medium with relative permittivity ϵr and relative permeability μr, and we have studied the effects of the surrounding material on the flow lines of the emitted energy. For a linear dipole moment in free space the flow lines of energy are straight lines, coming out of the dipole. When located in a medium, these field lines curve toward the dipole axis, due to the imaginary part of μr. Some field lines end on the dipole axis, giving a nonradiating contribution to the energy flow. For a rotating dipole moment in free space, each field line of energy flow lies on a cone around the axis perpendicular to the plane of rotation of the dipole moment. The field line pattern is an optical vortex. When embedded in a material, the cone shape of the vortex becomes a funnel shape, and the windings are much less dense than for the pattern in free space. This is again due to the imaginary part of μr. When the real part of μr is negative, the field lines of the vortex swirl around the dipole axis opposite to the rotation direction of the dipole moment. For a near-single-negative medium, the spatial extent of the vortex becomes huge. We compare the results for the magnetic dipole to the case of an embedded electric dipole. PMID:27140885

  16. Lunar magnetic field - Permanent and induced dipole moments

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Coleman, P. J., Jr.; Schubert, G.

    1974-01-01

    Apollo 15 subsatellite magnetic field observations have been used to measure both the permanent and the induced lunar dipole moments. Although only an upper limit of 1.3 x 10 to the 18th gauss-cubic centimeters has been determined for the permanent dipole moment in the orbital plane, there is a significant induced dipole moment which opposes the applied field, indicating the existence of a weak lunar ionosphere.

  17. Two methods of computing molecular dipole and quadrupole derivatives

    NASA Astrophysics Data System (ADS)

    Lazzeretti, P.; Zanasi, R.; Fowler, P. W.

    1988-01-01

    Polarized basis sets are used to compute dipole and quadrupole derivatives of the hydrides LiH, CH4, NH3, H2O, and HF. Analytic calculation of derivatives is compared with calculation via the dipole and quadrupole electric shielding tensors. With these basis sets, violation of the Hellmann-Feynman theorem is only about 0.01 a.u. in dipole derivatives and 0.02 a.u. in quadrupole derivatives.

  18. Dipole characterization of single neurons from their extracellular action potentials

    PubMed Central

    Victor, Jonathan D.

    2011-01-01

    The spatial variation of the extracellular action potentials (EAP) of a single neuron contains information about the size and location of the dominant current source of its action potential generator, which is typically in the vicinity of the soma. Using this dependence in reverse in a three-component realistic probe + brain + source model, we solved the inverse problem of characterizing the equivalent current source of an isolated neuron from the EAP data sampled by an extracellular probe at multiple independent recording locations. We used a dipole for the model source because there is extensive evidence it accurately captures the spatial roll-off of the EAP amplitude, and because, as we show, dipole localization, beyond a minimum cell-probe distance, is a more accurate alternative to approaches based on monopole source models. Dipole characterization is separable into a linear dipole moment optimization where the dipole location is fixed, and a second, nonlinear, global optimization of the source location. We solved the linear optimization on a discrete grid via the lead fields of the probe, which can be calculated for any realistic probe + brain model by the finite element method. The global source location was optimized by means of Tikhonov regularization that jointly minimizes model error and dipole size. The particular strategy chosen reflects the fact that the dipole model is used in the near field, in contrast to the typical prior applications of dipole models to EKG and EEG source analysis. We applied dipole localization to data collected with stepped tetrodes whose detailed geometry was measured via scanning electron microscopy. The optimal dipole could account for 96% of the power in the spatial variation of the EAP amplitude. Among various model error contributions to the residual, we address especially the error in probe geometry, and the extent to which it biases estimates of dipole parameters. This dipole characterization method can be applied to

  19. Mutual impedance of nonplanar-skew sinusoidal dipoles

    NASA Technical Reports Server (NTRS)

    Richmond, J. H.; Geary, N. H.

    1975-01-01

    The mutual impedance expressions for parallel dipoles in terms of sine-integrals and cosine-integrals have been published by King (1957). The investigation reported provides analogous expressions for nonparallel dipoles. The expressions presented are most useful when the monopoles are close together. The theory of moment methods shows an approach for employing the mutual impedance of filamentary sinusoidal dipoles to calculate the impedance and scattering properties of straight and bent wires with small but finite diameter.

  20. PROBING THE UNIVERSE'S TILT WITH THE COSMIC INFRARED BACKGROUND DIPOLE

    SciTech Connect

    Fixsen, D. J.; Kashlinsky, A. E-mail: alexander.kashlinsky@nasa.gov

    2011-06-10

    Conventional interpretation of the observed cosmic microwave background (CMB) dipole is that all of it is produced by local peculiar motions. Alternative explanations requiring part of the dipole to be primordial have received support from measurements of large-scale bulk flows. A test of the two hypotheses is whether other cosmic dipoles produced by collapsed structures later than the last scattering coincide with the CMB dipole. One background is the cosmic infrared background (CIB) whose absolute spectrum was measured to {approx}30% by the COBE satellite. Over the 100-500 {mu}m wavelength range its spectral energy distribution can provide a probe of its alignment with the CMB. This is tested with the COBE FIRAS data set which is available for such a measurement because of its low noise and frequency resolution which are important for Galaxy subtraction. Although the FIRAS instrument noise is in principle low enough to determine the CIB dipole, the Galactic foreground is sufficiently close spectrally to keep the CIB dipole hidden. A similar analysis is performed with DIRBE, which-because of the limited frequency coverage-provides a poorer data set. We discuss strategies for measuring the CIB dipole with future instruments to probe the tilt and apply it to the Planck, Herschel, and the proposed Pixie missions. We demonstrate that a future FIRAS-like instrument with instrument noise a factor of {approx}10 lower than FIRAS would make a statistically significant measurement of the CIB dipole. We find that the Planck and Herschel data sets will not allow a robust CIB dipole measurement. The Pixie instrument promises a determination of the CIB dipole and its alignment with either the CMB dipole or the dipole galaxy acceleration vector.

  1. Hairpin Furans and Giant Biaryls.

    PubMed

    Geng, Xin; Mague, Joel T; Donahue, James P; Pascal, Robert A

    2016-05-01

    The thermal reaction of two cyclopentadienones with 5,5'-binaphthoquinone or 6,6'-dimethoxy-5,5'-binaphthoquinone in refluxing nitrobenzene (210 °C) gives, in a single synthetic step that includes two Diels-Alder additions, two decarbonylations, and two dehydrogenations, giant biaryl bisquinones (compounds 13, 14, 15, 18, and 21). However, when two cyclopentadienones react with 6,6'-dimethoxy-5,5'-binaphthoquinone in nitrobenzene at higher temperatures (250-260 °C), the resulting products are molecular ribbons composed of two twisted aromatic systems fused to a heteropentahelicene (19, 20, and 22). These molecules are representatives of a new class of chiral polycyclic aromatic compounds, the "hairpin furans". Interestingly, reheating a dimethoxy-substituted giant biaryl (e.g., 21) in nitrobenzene at 260 °C does not yield the corresponding hairpin furan (22), and mechanistic studies indicate that some intermediate or byproduct of the synthesis of the giant biaryls is a reagent or catalyst necessary for the conversion of the dimethoxybiaryl to the furan. PMID:27040596

  2. Observed Properties of Giant Cells

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.; Upton, Lisa; Colegrove, Owen

    2014-01-01

    The existence of Giant Cells has been suggested by both theory and observation for over 45 years. We have tracked the motions of supergranules in SDO/HMI Doppler velocity data and find larger (Giant Cell) flows that persist for months. The flows in these cells are clockwise around centers of divergence in the north and counter-clockwise in the south. Equatorward flows are correlated with prograde flows - giving the transport of angular momentum toward the equator that is needed to maintain the Sun's rapid equatorial rotation. The cells are most pronounced at mid- and high-latitudes where they exhibit the rotation rates representative of those latitudes. These are clearly large, long-lived, cellular features, with the dynamical characteristics expected from the effects of the Sun's rotation, but the shapes of the cells are not well represented in numerical models. While the Giant Cell flow velocities are small (<10 m/s), their long lifetimes should nonetheless substantially impact the transport of magnetic flux in the Sun's near surface layers.

  3. An alternate end design for SSC dipoles

    SciTech Connect

    Peters, C.; Caspi, S.; Taylor, C.

    1989-02-01

    Experience in the SSC dipole program has shown that fabrication of cylindrical coil ends is difficult. Cable stiffness requires large forces to maintain the proper position of the conductors in the end during winding. After winding, the coil ends remain distorted nd significant motion of the need conductors is required to force the coil end into the molding cavity. Local mechanical stresses are high during this process and extra pieces of insulation are required to prevent turn-to-turn shorts from developing during the winding and molding steps. Prior to assembly the coil end is compressed in a mold cavity and injected with a filler material to correct surface irregularities and fill voids in the end. LBL has developed an alternate design which permits the conductors to be wound over the end using minimal force and technician coerosion. The conductors are placed on a conical surface where the largest diameter over the outer layer conductors is 10 cm. No coil end spaces or insulation pieces between turns are required. The conductor geometry was analytically optimized to meet SSC multipole requirements for the ends. The first 1-m dipole utilizing this end geometry has been constructed and successfully tested. Design and construction data are presented. Also model test results, including training and multipole measurements of the end are given. 1 ref., 12 figs., 3 tabs.

  4. Surface Dipole Control of Liquid Crystal Alignment.

    PubMed

    Schwartz, Jeffrey J; Mendoza, Alexandra M; Wattanatorn, Natcha; Zhao, Yuxi; Nguyen, Vinh T; Spokoyny, Alexander M; Mirkin, Chad A; Baše, Tomáš; Weiss, Paul S

    2016-05-11

    Detailed understanding and control of the intermolecular forces that govern molecular assembly are necessary to engineer structure and function at the nanoscale. Liquid crystal (LC) assembly is exceptionally sensitive to surface properties, capable of transducing nanoscale intermolecular interactions into a macroscopic optical readout. Self-assembled monolayers (SAMs) modify surface interactions and are known to influence LC alignment. Here, we exploit the different dipole magnitudes and orientations of carboranethiol and -dithiol positional isomers to deconvolve the influence of SAM-LC dipolar coupling from variations in molecular geometry, tilt, and order. Director orientations and anchoring energies are measured for LC cells employing various carboranethiol and -dithiol isomer alignment layers. The normal component of the molecular dipole in the SAM, toward or away from the underlying substrate, was found to determine the in-plane LC director orientation relative to the anisotropy axis of the surface. By using LC alignment as a probe of interaction strength, we elucidate the role of dipolar coupling of molecular monolayers to their environment in determining molecular orientations. We apply this understanding to advance the engineering of molecular interactions at the nanoscale. PMID:27090503

  5. Satellite sweeping in offset, tilted dipole fields

    NASA Technical Reports Server (NTRS)

    Paonessa, Mark T.; Cheng, Andrew F.

    1987-01-01

    The paper presents a theory for the longitudinally averaged satellite sweeping rate in an offset, tilted dipole magnetic field. It includes the reductions in the sweeping rate when the moon radius is not large compared to the gyroradius or the azimuthal drift distance during a bounce period. With a large tilt angle between the magnetic and rotation axes, moons make large excursions in dipole L value, and more than one moon can sweep at a given L. The sweeping rate peaks at the minimum L for each moon. If the gyroradius is large, additional peaks can occur when the particle mirrors near the moon latitude. To illustrate the theory, sweeping rates are evaluated for parameters relevant to the observations at Uranus by the Voyager 2 Low Energy Charged Particles Experiment. Calculated sweeping rates for ions and electrons are typically two or three orders of magnitude less than the strong-diffusion loss rate. The observation of sweeping signatures at Uranus would imply that pitch-angle scattering there occurs at a rate far below the strong-diffusion limit, contrasting with the situation for energetic ions in the inner Jovian magnetosphere.

  6. Brownian dipole rotator in alternating electric field.

    PubMed

    Rozenbaum, V M; Vovchenko, O Ye; Korochkova, T Ye

    2008-06-01

    The study addresses the azimuthal jumping motion of an adsorbed polar molecule in a periodic n -well potential under the action of an external alternating electric field. Starting from the perturbation theory of the Pauli equation with respect to the weak field intensity, explicit analytical expressions have been derived for the time dependence of the average dipole moment as well as the frequency dependences of polarizability and the average angular velocity, the three quantities exhibiting conspicuous stochastic resonance. As shown, unidirectional rotation can arise only provided simultaneous modulation of the minima and maxima of the potential by an external alternating field. For a symmetric potential of hindered rotation, the average angular velocity, if calculated by the second-order perturbation theory with respect to the field intensity, has a nonzero value only at n=2 , i.e., when two azimuthal wells specify a selected axis in the system. Particular consideration is given to the effect caused by the asymmetry of the two-well potential on the dielectric loss spectrum and other Brownian motion parameters. When the asymmetric potential in a system of dipole rotators arises from the average local fields induced by an orientational phase transition, the characteristics concerned show certain peculiarities which enable detection of the phase transition and determination of its parameters. PMID:18643221

  7. Brownian dipole rotator in alternating electric field

    NASA Astrophysics Data System (ADS)

    Rozenbaum, V. M.; Vovchenko, O. Ye.; Korochkova, T. Ye.

    2008-06-01

    The study addresses the azimuthal jumping motion of an adsorbed polar molecule in a periodic n -well potential under the action of an external alternating electric field. Starting from the perturbation theory of the Pauli equation with respect to the weak field intensity, explicit analytical expressions have been derived for the time dependence of the average dipole moment as well as the frequency dependences of polarizability and the average angular velocity, the three quantities exhibiting conspicuous stochastic resonance. As shown, unidirectional rotation can arise only provided simultaneous modulation of the minima and maxima of the potential by an external alternating field. For a symmetric potential of hindered rotation, the average angular velocity, if calculated by the second-order perturbation theory with respect to the field intensity, has a nonzero value only at n=2 , i.e., when two azimuthal wells specify a selected axis in the system. Particular consideration is given to the effect caused by the asymmetry of the two-well potential on the dielectric loss spectrum and other Brownian motion parameters. When the asymmetric potential in a system of dipole rotators arises from the average local fields induced by an orientational phase transition, the characteristics concerned show certain peculiarities which enable detection of the phase transition and determination of its parameters.

  8. Dipole Alignment in Rotating MHD Turbulence

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.; Fu, Terry; Morin, Lee

    2012-01-01

    We present numerical results from long-term CPU and GPU simulations of rotating, homogeneous, magnetohydrodynamic (MHD) turbulence, and discuss their connection to the spherically bounded case. We compare our numerical results with a statistical theory of geodynamo action that has evolved from the absolute equilibrium ensemble theory of ideal MHD turbulence, which is based on the ideal MHD invariants are energy, cross helicity and magnetic helicity. However, for rotating MHD turbulence, the cross helicity is no longer an exact invariant, although rms cross helicity becomes quasistationary during an ideal MHD simulation. This and the anisotropy imposed by rotation suggests an ansatz in which an effective, nonzero value of cross helicity is assigned to axisymmetric modes and zero cross helicity to non-axisymmetric modes. This hybrid statistics predicts a large-scale quasistationary magnetic field due to broken ergodicity , as well as dipole vector alignment with the rotation axis, both of which are observed numerically. We find that only a relatively small value of effective cross helicity leads to the prediction of a dipole moment vector that is closely aligned (less than 10 degrees) with the rotation axis. We also discuss the effect of initial conditions, dissipation and grid size on the numerical simulations and statistical theory.

  9. Projected Dipole Model for Quantum Plasmonics

    NASA Astrophysics Data System (ADS)

    Yan, Wei; Wubs, Martijn; Asger Mortensen, N.

    2015-09-01

    Quantum effects of plasmonic phenomena have been explored through ab initio studies, but only for exceedingly small metallic nanostructures, leaving most experimentally relevant structures too large to handle. We propose instead an effective description with the computationally appealing features of classical electrodynamics, while quantum properties are described accurately through an infinitely thin layer of dipoles oriented normally to the metal surface. The nonlocal polarizability of the dipole layer—the only introduced parameter—is mapped from the free-electron distribution near the metal surface as obtained with 1D quantum calculations, such as time-dependent density-functional theory (TDDFT), and is determined once and for all. The model can be applied in two and three dimensions to any system size that is tractable within classical electrodynamics, while capturing quantum plasmonic aspects of nonlocal response and a finite work function with TDDFT-level accuracy. Applying the theory to dimers, we find quantum corrections to the hybridization even in mesoscopic dimers, as long as the gap itself is subnanometric.

  10. Dipole Transport: a New Confinement Paradigm

    NASA Astrophysics Data System (ADS)

    Kesner, J.; Garnier, D.; Mauel, M.

    2014-10-01

    In a tokamak-like device turbulence will grow up to a level determined by non-linear processes. The associated transport, in combination with particle and energy sources then determines the density and temperature profiles of the plasma. This paradigm is fundamentally different for a plasma that is confined in a dipole field. In a dipole, levitated to avoid losses to the supports, the plasma will assume a stationary profile determined only by the specific volume, V (Ψ) , (which is determined by the magnetic geometry). Independent of the source and sink profiles for particles and energy, turbulence will grow up to a sufficient level so that diffusion and pinch dynamics will establish stationary profiles characterized by ne ~ 1 / V and p ~ 1 /V 5 / 3 . This process is observed in magnetospheric plasmas and we have observed it in the laboratory in LDX. For example, with edge fueling in LDX we observed that the stationary (peaked) density profile (n ~ 1 / V) was established by a turbulence-driven density pinch whereas in recent experiments with core (pellet) fueling turbulence was observed to relax the density back to the stationary profile on a similar timescale. Supported by the NSF-DOE Partnership in Plasma Science Grants DE-FG02-00ER54585 and PHY-1201896.

  11. Projected Dipole Model for Quantum Plasmonics.

    PubMed

    Yan, Wei; Wubs, Martijn; Asger Mortensen, N

    2015-09-25

    Quantum effects of plasmonic phenomena have been explored through ab initio studies, but only for exceedingly small metallic nanostructures, leaving most experimentally relevant structures too large to handle. We propose instead an effective description with the computationally appealing features of classical electrodynamics, while quantum properties are described accurately through an infinitely thin layer of dipoles oriented normally to the metal surface. The nonlocal polarizability of the dipole layer-the only introduced parameter-is mapped from the free-electron distribution near the metal surface as obtained with 1D quantum calculations, such as time-dependent density-functional theory (TDDFT), and is determined once and for all. The model can be applied in two and three dimensions to any system size that is tractable within classical electrodynamics, while capturing quantum plasmonic aspects of nonlocal response and a finite work function with TDDFT-level accuracy. Applying the theory to dimers, we find quantum corrections to the hybridization even in mesoscopic dimers, as long as the gap itself is subnanometric. PMID:26451583

  12. SSC 50 mm collider dipole cryostat design

    SciTech Connect

    Nicol, T.H.

    1992-04-01

    The cryostat of a Superconducting Super Collider (SSC) dipole magnet consists of all magnet components except the magnet assembly itself. It serves to support the magnet accurately and reliably within the vacuum vessel, provide all required cryogenic piping, and to insulate the cold mass from heat radiated and conducted from the environment. It must function reliably during storage, shipping and handling, normal magnet operation, quenches, and seismic excitations, and must be manufacturable at low cost. The major components of the cryostat are the vacuum vessel, thermal shields, multilayer insulation system, cryogenic piping, interconnections, and suspension system. The overall design of a cryostat for superconducting accelerator magnets requires consideration of fluid flow, proper selection of materials for their thermal and structural performance at both ambient and operating temperature, and knowledge of the environment to which the magnets will be subjected over the course of their expected operating life. This paper describes the design of the current SSC dipole magnet cryostat and includes discussions on the structural and thermal considerations involved in the development of each of the major systems.

  13. Decomposing the electromagnetic response of magnetic dipoles to determine the geometric parameters of a dipole conductor

    NASA Astrophysics Data System (ADS)

    Desmarais, Jacques K.; Smith, Richard S.

    2016-03-01

    A novel automatic data interpretation algorithm is presented for modelling airborne electromagnetic (AEM) data acquired over resistive environments, using a single-component (vertical) transmitter, where the position and orientation of a dipole conductor is allowed to vary in three dimensions. The algorithm assumes that the magnetic fields produced from compact vortex currents are expressed as a linear combinations of the fields arising from dipoles in the subsurface oriented parallel to the [1, 0, 0], [0, 1, 0], and [0, 0, 1], unit vectors. In this manner, AEM responses can be represented as 12 terms. The relative size of each term in the decomposition can be used to determine geometrical information about the orientation of the subsurface conductivity structure. The geometrical parameters of the dipole (location, depth, dip, strike) are estimated using a combination of a look-up table and a matrix inverted in a least-squares sense. Tests on 703 synthetic models show that the algorithm is capable of extracting most of the correct geometrical parameters of a dipole conductor when three-component receiver data is included in the interpretation procedure. The algorithm is unstable when the target is perfectly horizontal, as the strike is undefined. Ambiguities may occur in predicting the orientation of the dipole conductor if y-component data is excluded from the analysis. Application of our approach to an anomaly on line 15 of the Reid Mahaffy test site yields geometrical parameters in reasonable agreement with previous authors. However, our algorithm provides additional information on the strike and offset from the traverse line of the conductor. Disparities in the values of predicted dip and depth are within the range of numerical precision. The index of fit was better when strike and offset were included in the interpretation procedure. Tests on the data from line 15701 of the Chibougamau MEGATEM survey shows that the algorithm is applicable to situations where

  14. Detecting the dipole moment of a single carbon monoxide molecule

    SciTech Connect

    Schwarz, A. Köhler, A.; Grenz, J.; Wiesendanger, R.

    2014-07-07

    Using non-contact atomic force microscopy with metallic tips enabled us to detect the electrostatic dipole moment of single carbon monoxide (CO) molecules adsorbed on three very different substrates. The observed distance dependent contrast can be explained by an interplay between the attractive van der Waals interaction and the repulsive electrostatic interaction, respectively, with the latter stemming from antiparallel aligned dipoles in tip and molecule. Our results suggest that metallic as well as CO-functionalized tips are able to probe electrostatic properties of polar molecules and that repulsive dipole-dipole interactions have to be considered when interpreting complex contrast patterns.

  15. Measurement of the b hadron lifetime with the dipole method

    NASA Astrophysics Data System (ADS)

    Buskulic, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Minard, M.-N.; Pietrzyk, B.; Ariztizabal, F.; Comas, P.; Crespo, J. M.; Delfino, M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Gaitan, V.; Garrido, Ll.; Mattison, T.; Pacheco, A.; Padilla, C.; Pascual, A.; Creanza, D.; de Palma, M.; Farilla, A.; Iaselli, G.; Maggi, G.; Marinelli, N.; Natali, S.; Nuzzo, S.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Chai, Y.; Hu, H.; Huang, D.; Huang, X.; Lin, J.; Wang, T.; Xie, Y.; Xu, D.; Xu, R.; Zhang, J.; Zhang, L.; Zhao, W.; Bonvicini, G.; Boudreau, J.; Casper, D.; Drevermann, H.; Forty, R. W.; Ganis, G.; Gay, C.; Hagelberg, R.; Harvey, J.; Hilgart, J.; Jacobsen, R.; Jost, B.; Knobloch, J.; Lehraus, I.; Maggi, M.; Markou, C.; Martinez, M.; Mato, P.; Meinhard, H.; Minten, A.; Miquel, R.; Moser, H.-G.; Palazzi, P.; Pater, J. R.; Perlas, J. A.; Pusztaszeri, J.-F.; Ranjard, F.; Rolandi, L.; Rothberg, J.; Ruan, T.; Saich, M.; Schlatter, D.; Schmelling, M.; Sefkow, F.; Tejessy, W.; Tomalin, I. R.; Veenhof, R.; Wachsmuth, H.; Wasserbaech, S.; Wiedenmann, W.; Wildish, T.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; Badaud, F.; Bardadin-Otwinowska, M.; El Fellous, R.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Prulhière, F.; Saadi, F.; Fearnley, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Møllerud, R.; Nilsson, B. S.; Kyriakis, A.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Badier, J.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, P.; Fouque, G.; Orteu, S.; Rougé, A.; Rumpf, M.; Tanaka, R.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Veitch, E.; Focardi, E.; Moneta, L.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Ikeda, M.; Levinthal, D.; Antonelli, A.; Baldini, R.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Cerutti, F.; Chiarella, V.; D'Ettorre-Piazzoli, B.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Picchi, P.; Colrain, P.; Ten Have, I.; Lynch, J. G.; Maitland, W.; Morton, W. T.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Smith, M. G.; Thompson, A. S.; Turnbull, R. M.; Brandl, B.; Braun, O.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E. E.; Maumary, Y.; Putzer, A.; Rensch, B.; Stahl, A.; Tittel, K.; Wunsch, M.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Cattaneo, M.; Colling, D. J.; Dornan, P. J.; Greene, A. M.; Hassard, J. F.; Lieske, N. M.; Moutoussi, A.; Nash, J.; Patton, S.; Payne, D. G.; Phillips, M. J.; San Martin, G.; Sedgbeer, J. K.; Wright, A. G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Vogl, R.; Bowdery, C. K.; Brodbeck, T. J.; Finch, A. J.; Foster, F.; Hughes, G.; Jackson, D.; Keemer, N. R.; Nuttall, M.; Patel, A.; Sloan, T.; Snow, S. W.; Whelan, E. P.; Kleinknecht, K.; Raab, J.; Renk, B.; Sander, H.-G.; Schmidt, H.; Walther, S. M.; Wanke, R.; Wolf, B.; Zimmermann, A.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Carr, J.; Coyle, P.; Drinkard, J.; Etienne, F.; Nicod, D.; Papalexiou, S.; Payre, P.; Roos, L.; Rousseau, D.; Schwemling, P.; Talby, M.; Adlung, S.; Assmann, R.; Bauer, C.; Blum, W.; Brown, D.; Cattaneo, P.; Dehning, B.; Dietl, H.; Dydak, F.; Frank, M.; Halley, A. W.; Jakobs, K.; Lauber, J.; Lütjens, G.; Lutz, G.; Männer, W.; Richter, R.; Schröder, J.; Schwarz, A. S.; Settles, R.; Seywerd, H.; Stierlin, U.; Stiegler, U.; St. Denis, R.; Wolf, G.; Alemany, R.; Boucrot, J.; Callot, O.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Jaffe, D. E.; Janot, P.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Schune, M.-H.; Veillet, J.-J.; Videau, I.; Zhang, Z.; Abbaneo, D.; Bagliesi, G.; Batignani, G.; Bottigli, U.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Ciulli, V.; Dell'Orso, R.; Ferrante, I.; Fidecaro, F.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Mannelli, E. B.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Valassi, A.; Vannini, C.; Venturi, A.; Verdini, P. G.; Walsh, J.; Betteridge, A. P.; Gao, Y.; Green, M. G.; March, P. V.; Mir, Ll. M.; Medcalf, T.; Quazi, I. S.; Strong, J. A.; West, L. R.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Norton, P. R.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Duarte, H.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J.-F.; Rosowsky, A.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Si Mohand, D.; Vallage, B.; Johnson, R. P.; Litke, A. M.; Taylor, G.; Wear, J.; Ashman, J. G.; Babbage, W.; Booth, C. N.; Buttar, C.; Cartwright, S.; Combley, F.; Dawson, I.; Thompson, L. F.; Barbeiro, E.; Böhrer, A.; Brandt, S.; Cowan, G.; Grupen, C.; Lutters, G.; Rivera, F.; Schäfer, U.; Smolik, L.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Ragusa, F.; Bellantoni, L.; Chen, W.; Conway, J. S.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; Grahl, J.; Harton, J. L.; Hayes, O. J.; Nachtman, J. M.; Pan, Y. B.; Saadi, Y.; Schmitt, M.; Scott, I.; Sharma, V.; Shi, Z. H.; Turk, J. D.; Walsh, A. M.; Weber, F. V.; Sau Lan Wu; Wu, X.; Zheng, M.; Zobernig, G.; Aleph Collaboration

    1993-09-01

    A measurement of the average lifetime of b hadrons has been performed with dipole method on a sample of 260 000 hadronic Z decays recorded with the ALEPH detector during 1991. The dipole is the distance between the vertices built in the opposite hemispheres. The mean dipole is extracted from all the events without attempting b enrichment. Comparing the average of the data dipole distribution with a Monte Carlo calibration curve obtained with different b lifetimes, an average b hadron lifetime of 1.51±0.08 ps is extracted.

  16. The Dipole Model and Phase Transitions in Biological Membranes

    PubMed Central

    Almeida, Silverio P.; Bond, James D.; Ward, Thomas C.

    1971-01-01

    Assuming the dipole model for a membrane, approximate calculations are made which employ a dipole-dipole interaction energy. The calculations are based upon the assumption of cooperative coupling of membrane polar molecules and make use of the Bragg-Williams approximation. A theoretical estimate is made of the critical temperature at which phase changes might occur in certain biological membranes. Proposals are presented which explain how the dipole transition might relate to the sometimes observed thermal phase transitions in biological membranes. PMID:5134212

  17. Effects of dipole-dipole interaction between cigar-shaped BECs of cold alkali atoms: towards inverse-squared interactions

    NASA Astrophysics Data System (ADS)

    Yu, Yue; Luo, Zhuxi; Wang, Ziqiang

    2014-07-01

    We show that the dipole-dipole coupling between Wannier modes in cigar-shaped Bose-Einstein condensates (BECs) is significantly enhanced while the short-range coupling is strongly suppressed. As a result, the dipole-dipole interaction can become the dominant interaction between ultracold alkali Bose atoms. In the long length limit of a cigar-shaped BEC, the resulting effective one-dimensional models possess an effective inverse squared interacting potential, the Calogero-Sutherland potential, which plays a fundamental role in many fields of contemporary physics; but its direct experimental realization has been a challenge for a long time. We propose to realize the Calogero-Sutherland model in ultracold alkali Bose atoms and study the effects of the dipole-dipole interaction.

  18. Guiding the Giant

    NASA Astrophysics Data System (ADS)

    1998-08-01

    New ESO Survey Provides Targets for the VLT Giant astronomical telescopes like the ESO Very Large Telescope (VLT) must be used efficiently. Observing time is expensive and there are long waiting lines of excellent research programmes. Thus the work at the telescope must be very well prepared and optimized as much as possible - mistakes should be avoided and no time lost! Astronomers working with the new 8-m class optical/infrared telescopes must base their observations on detailed lists of suitable target objects if they want to perform cutting-edge science. This is particularly true for research programmes that depend on observations of large samples of comparatively rare, distant objects. This type of work requires that extensive catalogues of such objects must be prepared in advance. One such major catalogue - that will serve as a very useful basis for future VLT observations - has just become available from the new ESO Imaging Survey (EIS). The Need for Sky Surveys Astronomers have since long recognized the need to carry out preparatory observations with other telescopes in order to "guide" large telescopes. To this end, surveys of smaller or larger parts of the sky have been performed by wide-field telescopes, paving the way for subsequent work at the limits of the largest available ground-based telescopes. For instance, a complete photographic survey of the sourthern sky (declination < -17.5°) was carried out in the 1970's with the ESO 1-metre Schmidt Telescope in support of the work at the 3.6-m telescope at the ESO La Silla observatory. However, while until recently most observational programmes could rely on samples of objects found on photographic plates, this is no longer possible. New image surveys must match the fainter limiting magnitudes reached by the new and larger telescopes. Modern digital, multi-colour, deep imaging surveys have thus become an indispensable complement to the 8-m telescopes. The new generation of imaging surveys will, without

  19. Cabergoline Treatment in Invasive Giant Prolactinoma

    PubMed Central

    Alsubaie, Sadeem; Almalki, Mussa H

    2014-01-01

    Patients with invasive giant prolactinoma suffer from a constellation of symptoms including headache, blurred vision, lethargy, and sexual dysfunction. Cabergoline, a potent dopamine agonist, is a known medication prescribed for the treatment of invasive giant prolactinoma. Here, we report a case of invasive giant prolactinoma in a 52-year-old Saudi male with dramatic response to cabergoline treatment clinically, biochemically, and radiologically. PMID:25002819

  20. Speciation and phylogeography of giant petrels Macronectes.

    PubMed

    Techow, N M S M; O'Ryan, C; Phillips, R A; Gales, R; Marin, M; Patterson-Fraser, D; Quintana, F; Ritz, M S; Thompson, D R; Wanless, R M; Weimerskirch, H; Ryan, P G

    2010-02-01

    We examine global phylogeography of the two forms of giant petrel Macronectes spp. Although previously considered to be a single taxon, and despite debate over the status of some populations and the existence of minimal genetic data (one mitochondrial cytochrome b sequence per form), the current consensus based on morphology is that there are two species, Northern Giant Petrel M. halli and Southern Giant Petrel M. giganteus. This study examined genetic variation at cytochrome b as well as six microsatellite loci in giant petrels from 22 islands, representing most island groups at which the two species breed. Both markers support separate species status, although sequence divergence in cytochrome b was only 0.42% (corrected). Divergence was estimated to have occurred approximately 0.2mya, but with some colonies apparently separated for longer (up to 0.5 my). Three clades were found within giant petrels, which separated approximately 0.7mya, with the Southern Giant Petrel paraphyletic to a monophyletic Northern Giant Petrel. There was evidence of past fragmentation during the Pleistocene, with subsequent secondary contact within Southern Giant Petrels. The analysis also suggested a period of past population expansion that corresponded roughly to the timing of speciation and the separation of an ancestral giant petrel population from the fulmar Fulmarus clade. PMID:19755164

  1. Spontaneous thrombosis in giant intracranial aneurysms.

    PubMed Central

    Whittle, I R; Dorsch, N W; Besser, M

    1982-01-01

    Twelve patients in a series of 22 with giant intracranial aneurysms demonstrated neuroradiological features of partial or total spontaneous intra-aneurysmal thrombosis. The presence of this intra-aneurysmal clot significantly altered the computed tomographic appearance of the giant aneurysm. Massive intra-aneurysmal thrombosis did not protect against subarachnoid haemorrhage and the likelihood of rupture of a clot containing giant aneurysm was not significantly different from that of a non-thrombosed giant aneurysm. Although parent artery occlusion from a thrombosed giant aneurysm, and massive aneurysmal thrombosis leading to the formation of giant serpentine aneurysm were documented, these are rare epiphenomena. The risk of embolisation from a partially thrombosed giant aneurysm, which was documented in one case, would appear to be greater than that from a non-thrombosed giant aneurysm. The findings in this series, and a review of literature, suggest that the presence of intra-aneurysmal clot in giant intracranial aneurysms has little prognostic significance and does not alter the management or outcome after treatment. Images PMID:7175528

  2. Near-Field Magnetic Dipole Moment Analysis

    NASA Technical Reports Server (NTRS)

    Harris, Patrick K.

    2003-01-01

    This paper describes the data analysis technique used for magnetic testing at the NASA Goddard Space Flight Center (GSFC). Excellent results have been obtained using this technique to convert a spacecraft s measured magnetic field data into its respective magnetic dipole moment model. The model is most accurate with the earth s geomagnetic field cancelled in a spherical region bounded by the measurement magnetometers with a minimum radius large enough to enclose the magnetic source. Considerably enhanced spacecraft magnetic testing is offered by using this technique in conjunction with a computer-controlled magnetic field measurement system. Such a system, with real-time magnetic field display capabilities, has been incorporated into other existing magnetic measurement facilities and is also used at remote locations where transport to a magnetics test facility is impractical.

  3. Concentric Titled Double-Helix Dipole Magnets

    SciTech Connect

    Rainer Meinke, Ph.D; Carl Goodzeit; Millicent Ball, Ph.D

    2003-09-05

    The high magnetic fields required for future accelerator magnets can only be achieved with Nb3Sn, other A15 or HTS type conductors, which are brittle and sensitive to mechanical strain. The traditional ''cosine-theta'' dipole configuration has intrinsic drawbacks that make it difficult and expensive to employ such conductors in these designs. Some of these problems involve (1) difficulty in applying enough pre-stress to counteract Lorentz forces without compromising conductor performance; (2) small minimum bend radii of the conductor necessitating the intricate wind-and-react coil fabrication; (3) complex spacers in particular for coil ends and expensive tooling for coil fabrication; (4) typically only 2/3 of the coil aperture can be used with achievable field uniformity.

  4. Magnetic field decay in model SSC dipoles

    SciTech Connect

    Gilbert, W.S.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Green, M.A.; Green, M.I.; Scanlan, R.M.

    1988-08-01

    We have observed that some of our model SSC dipoles have long time constant decays of the magnetic field harmonics with amplitudes large enough to result in significant beam loss, if they are not corrected. The magnets were run at constant current at the SSC injection field level of 0.3 tesla for one to three hours and changes in the magnetic field were observed. One explanation for the observed field decay is time dependent superconductor magnetization. Another explanation involves flux creep or flux flow. Data are presented on how the decay changes with previous flux history. Similar magnets with different Nb-Ti filament spacings and matrix materials have different long time field decay. A theoretical model using proximity coupling and flux creep for the observed field decay is discussed. 10 refs., 5 figs., 2 tabs.

  5. Beam optical properties of the NSLS dipoles

    SciTech Connect

    Galayda, J.N.; Blumberg, L.N.; Heese, R.N.; Hsieh, H.C.H.

    1981-01-01

    Presently there is much interest in low energy (<1 GeV) electron storage rings as sources of synchrotron radiation and for studies of the free electron laser. The economics and physics of these storage rings favor the use of bending magnets with small radius of curvature and large bend angle. Some general features of such magnets and the results of magnetic measurements of the dipole magnets of the NSLS booster and storage rings are discussed. The magnetic measurements are interpreted in terms of the magnet geometry and saturation characteristics. Transport functions describing the linear and nonlinear focusing properties of the magnets, parametrized in terms of their curvature and fringe field length are discussed.

  6. Systematic Study of the Pygmy Dipole Resonance

    NASA Astrophysics Data System (ADS)

    Derya, V.; Endres, J.; Harakeh, M. N.; Savran, D.; Wörtche, H. J.; Zilges, A.

    2012-05-01

    In recent years, a systematic comparative study of the pygmy dipole resonance (PDR) using the (γ,γ') and the (α,α'γ) reactions on the nuclei 140Ce, 138Ba, 124Sn, 94Mo, and 48Ca was performed. The aim of this systematic study is to explore the structure of the PDR by the usage of two complementary probes and several different nuclei. The real-photon scattering experiments were performed at the S-DALINAC in Darmstadt, Germany, while the (α, α'γ) coincidence experiments were performed at the Big-Bite Spectrometer (BBS) at KVI in Groningen, The Netherlands. The comparison of the results from both kinds of experiments showed an energetic splitting of the PDR into two parts that might be due to the different isospin character of these states. First experimental results of the (α, α'γ) experiments on the nuclei 94Mo and 48Ca will be presented.

  7. Splitting of the Pygmy Dipole Resonance

    NASA Astrophysics Data System (ADS)

    Savran, D.; Endres, J.; Harakeh, M. N.; Pietralla, N.; Sonnabend, K.; Stoica, V. I.; Wörtche, H. J.; van den Berg, A. M.; Zilges, A.

    2011-09-01

    We report on experiments using the (α, α' γ) method to investigate the structure of the Pygmy Dipole Resonance (PDR) in the nuclei 94Mo, 124Sn, 138Ba and 140Ce. The experiments were performed with the Big-Bite Spectrometer (BBS) at the KVI at an incident energy of Eα = 136 MeV. The method allows a clean separation of the PDR from other excitations in the same energy region by selecting the ground-state γ-decay channel. In addition, the high resolution of the γ-ray spectroscopy using high-purity Germanium detectors allows a state-to-state analysis even in the case of the rather high level density of the investigated nuclei. The comparison to (γ,γ') experiments on the same nuclei reveals a splitting of the PDR into two groups of states with different underlying structure.

  8. Novel Design of Superconducting Helical Dipole Magnet

    NASA Astrophysics Data System (ADS)

    Meinke, R.; Senti, M.; Stelzer, G.

    1997-05-01

    Superconducting helical dipole magnets with a nominal field of 4 Tesla are needed for the spin physics program at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The magnets are required to operate at a relatively low current of 400 A since many of these magnets have to be independently controlled. The Advanced Magnet Lab, Inc., in Palm Bay, FL has designed and built two prototype magnets using advanced computer controlled coil winding technology. The AML design is extremely cost effective since it avoids magnet specific tooling despite the required complex coil pattern and any precision machined inserts or spacers. It is the first time an accelerator magnet of this technology has reached a field above 4 Tesla. Results from the prototype testing at BNL are presented.

  9. Nuclear electric dipole moment of 3He

    SciTech Connect

    Stetcu, Ionel; Friar, J L; Hayes, A C; Liu, C P; Navratil, P

    2008-01-01

    In the no-core shell model (NCSM) framework, we calculate the {sup 3}He electric dipole moment (EDM) generated by parity- and time-reversal violation in the nucleon-nucleon interaction. While the results are somehow sensitive to the interaction model chosen for the strong two- and three-body interactions, we demonstrate the pion-exchange dominance to the EDM of {sup 3}He, if the coupling constants for {pi}, {rho} and {omega}-exchanges are of comparable magnitude, as expected. Finally, our results suggest that a measurement of {sup 3}He EDM would be complementary to the currently planned neutron and deuteron experiments, and would constitute a powerful constraint to the models of the pion P- and T-violating interactions.

  10. Search for the Neutron Electric Dipole Moment

    SciTech Connect

    Plaster, Brad

    2010-08-04

    Searches for the neutron electric dipole moment (EDM) are motivated by their highly suppressed Standard Model value. The observation of a non-zero signal in the next generation of experiments would point unambiguously to the existence of new physics beyond the Standard Model. Several ongoing efforts worldwide hold the potential for an up to two-orders-of-magnitude improvement beyond the current upper limit on the neutron EDM of 2.9x10{sup -6} e-cm. In this talk, I review the basic measurement principles of neutron EDM searches, then discuss a new experiment to be carried out in the United States at the Spallation Neutron Source with ultracold neutrons and an in-situ '3He''co-magnetometer'.

  11. Intrinsic surface dipole in topological insulators.

    PubMed

    Fregoso, Benjamin M; Coh, Sinisa

    2015-10-28

    We calculate the local density of states of two prototypical topological insulators (Bi2Se3 and Bi2Te2Se) as a function of distance from the surface within density functional theory. We find that, in the absence of disorder or doping, there is a 2 nm thick surface dipole the origin of which is the occupation of the topological surface states above the Dirac point. As a consequence, the bottom of the conduction band is bent upward by about 75 meV near the surface, and there is a hump-like feature associated with the top of the valence band. We expect that band bending will occur in all pristine topological insulators as long as the Fermi level does not cross the Dirac point. Our results show that topological insulators are intrinsic Schottky barrier solar cells. PMID:26440802

  12. Search for a Neutron Electric Dipole Moment

    PubMed Central

    Golub, R.; Huffman, P. R.

    2005-01-01

    The possible existence of a nonzero electric dipole moment (EDM) of the neutron is of great fundamental interest in itself and directly impacts our understanding of the nature of electro-weak and strong interactions. The experimental search for this moment has the potential to reveal new sources of T and CP violation and to challenge calculations that propose extensions to the Standard Model. The goal of the current experiment is to significantly improve the measurement sensitivity to the neutron EDM over what is reported in the literature. The experiment has the potential to either measure the magnitude of the neutron EDM or to lower the current experimental limit by two orders of magnitude. Achieving these objectives will have a major impact on our understanding of the physics of both weak and strong interactions. PMID:27308116

  13. Search for the Neutron Electric Dipole Moment

    NASA Astrophysics Data System (ADS)

    Plaster, Brad

    2010-08-01

    Searches for the neutron electric dipole moment (EDM) are motivated by their highly suppressed Standard Model value. The observation of a non-zero signal in the next generation of experiments would point unambiguously to the existence of new physics beyond the Standard Model. Several ongoing efforts worldwide hold the potential for an up to two-orders-of-magnitude improvement beyond the current upper limit on the neutron EDM of 2.9×10-6 e-cm. In this talk, I review the basic measurement principles of neutron EDM searches, then discuss a new experiment to be carried out in the United States at the Spallation Neutron Source with ultracold neutrons and an in-situ 3He "co-magnetometer".

  14. Roll measurement of Tevatron dipoles and quadrupoles

    SciTech Connect

    Volk, J.T.; Elementi, L.; Gollwitzer, K.; Jostlein, H.; Nobrega, F.; Shiltsev, V.; Stefanski, R.

    2006-09-01

    In 2003 a simple digital level system was developed to allow for rapid roll measurements of all dipoles and quadrupoles in the Tevatron. The system uses a Mitutoyo digital level and a PC running MS WINDOWS XP and LAB VIEW to acquire data on the upstream and downstream roll of each magnet. The system is sufficiently simple that all 1,000 magnets in the Tevatron can be measured in less than 3 days. The data can be quickly processed allowing for correction of rolled magnets by the Fermilab alignment group. Data will be presented showing the state of the Tevatron in 2003 and the changes in rolls as measured in each shutdown since then.

  15. Active flutter suppression using dipole filters

    NASA Technical Reports Server (NTRS)

    Srinathkumar, S.; Waszak, Martin R.

    1992-01-01

    By using traditional control concepts of gain root locus, the active suppression of a flutter mode of a flexible wing is examined. It is shown that the attraction of the unstable mode towards a critical system zero determines the degree to which the flutter mode can be stabilized. For control situations where the critical zero is adversely placed in the complex plane, a novel compensation scheme called a 'Dipole' filter is proposed. This filter ensures that the flutter mode is stabilized with acceptable control energy. The control strategy is illustrated by designing flutter suppression laws for an active flexible wing (AFW) wind-tunnel model, where minimal control effort solutions are mandated by control rate saturation problems caused by wind-tunnel turbulence.

  16. Warm Disks from Giant Impacts

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-10-01

    In the process of searching for exoplanetary systems, weve discovered tens of debris disks close around distant stars that are especially bright in infrared wavelengths. New research suggests that we might be looking at the late stages of terrestrial planet formation in these systems.Forming Terrestrial PlanetsAccording to the widely-accepted formation model for our solar-system, protoplanets the size of Mars formed within a protoplanetary disk around our Sun. Eventually, the depletion of the gas in the disk led the orbits of these protoplanets to become chaotically unstable. Finally, in the giant impact stage, many of the protoplanets collided with each other ultimately leading to the formation of the terrestrial planets and their moons as we know them today.If giant impact stages occur in exoplanetary systems, too leading to the formation of terrestrial exoplanets how would we detect this process? According to a study led by Hidenori Genda of the Tokyo Institute of Technology, we might be already be witnessing this stage in observations of warm debris disks around other stars. To test this, Genda and collaborators model giant impact stages and determine what we would expect to see from a system undergoing this violent evolution.Modeling CollisionsSnapshots of a giant impact in one of the authors simulations. The collision causes roughly 0.05 Earth masses of protoplanetary material to be ejected from the system. Click for a closer look! [Genda et al. 2015]The collaborators run a series of simulations evolving protoplanetary bodies in a solar system. The simulations begin 10 Myr into the lifetime of the solar system, i.e., after the gas from the protoplanetary disk has had time to be cleared and the protoplanetary orbits begin to destabilize. The simulations end when the protoplanets are done smashing into each other and have again settled into stable orbits, typically after ~100 Myr.The authors find that, over an average giant impact stage, the total amount of

  17. Antenna impedance measurements in a magnetized plasma. II. Dipole antenna

    SciTech Connect

    Blackwell, David D.; Walker, David N.; Messer, Sarah J.; Amatucci, William E.

    2007-09-15

    This paper presents experimental impedance measurements of a dipole antenna immersed in a magnetized plasma. The impedance was derived from the magnitude and phase of the reflected power using a network analyzer over a frequency range of 1 MHz-1 GHz. The plasma density was varied between 10{sup 7} and 10{sup 10} cm{sup -3} in weakly ({omega}{sub ce}<{omega}{sub pe}) and strongly ({omega}{sub ce}>{omega}{sub pe}) magnetized plasmas in the Space Physics Simulation Chamber at the Naval Research Laboratory. Over this range of plasma conditions the wavelength in the plasma varies from the short dipole limit ({lambda}>>L) to the long dipole limit ({lambda}{approx}L). As with previous impedance measurements, there are two resonant frequencies observed as frequencies where the impedance of the antenna is real. Measurements have indicated that in the short dipole limit the majority of the power deposition takes place at the lower resonance frequency which lies between the cyclotron frequency and the upper hybrid frequency. These measured curves agree very well with the analytic theory for a short dipole in a magnetoplasma. In the long dipole regime, in addition to the short dipole effects still being present, there is resonant energy deposition which peaks at much higher frequencies and correlates to 1/2 and 3/2 wavelength dipole resonances. The wavelengths in the plasma predicted by these resonances are consistent with the antenna radiating R and L-waves.

  18. Complete and rigorous analysis of electromagnetically coupled transverse microstrip dipole

    NASA Astrophysics Data System (ADS)

    Lepeltier, P.; Floc'h, J. M.; Citerne, J.

    1987-07-01

    A rigorous and complete analysis of the electromagnetically coupled transverse microstrip dipole is presented. This new feeding process offers an alternative solution, which is especially interesting when it is necessary to excite several dipoles from the same line. The theoretical results are compared to experimental measurements in X-band for the input impedance and the radiation patterns (co- and crosspolarization).

  19. The transverse current on a strip dipole antenna

    NASA Astrophysics Data System (ADS)

    Wunsch, A. D.

    1983-04-01

    The magnitude and distribution of the current flow transverse to the axis of a small strip dipole antenna is evaluated numerically by means of the moment method. This current is found to be small compared to the axial current and to be a sensitive function of the dipole width.

  20. The mathematical modeling of grouping the dipole water clusters

    NASA Astrophysics Data System (ADS)

    Shaidurov, Vladimir; Kornienko, Viktoria; Vyatkin, Alexander

    2016-08-01

    In the present paper, a physical-mathematical model and a computational algorithm implementing the model are proposed to study the behavior of particles having an electric dipole moment in an external electric field. Computational experiments demonstrate the orientation dynamics of water clusters with the increase of the generated field. The dipole properties of some water clusters were previously determined using Hyperchem program.

  1. Helical dipole magnets for polarized protons in RHIC

    SciTech Connect

    Syphers, M.; Courant, E.; Fischer, W.

    1997-07-01

    Superconducting helical dipole magnets will be used in the Brookhaven Relativistic Heavy Ion Collider (RHIC) to maintain polarization of proton beams and to perform localized spin rotations at the two major experimental detector regions. Requirements for the helical dipole system are discussed, and magnet prototype work is reported.

  2. Dipole modulation in tensor modes: signatures in CMB polarization

    NASA Astrophysics Data System (ADS)

    Zarei, Moslem

    2015-06-01

    In this work we consider a dipole asymmetry in tensor modes and study the effects of this asymmetry on the angular power spectra of CMB. We derive analytical expressions for the and in the presence of such dipole modulation in tensor modes for . We also discuss on the amplitude of modulation term and show that the is considerably modified due to this term.

  3. Electric dipole moment of the electron and of the neutron

    NASA Technical Reports Server (NTRS)

    Barr, S. M.; Zee, A.

    1990-01-01

    It is shown that if Higgs-boson exchange mediates CP violation a significant electric dipole moment for the electron can result. Analogous effects can contribute to the neutron's electric dipole moment at a level competitive with Weinberg's three-gluon operator.

  4. Multiple dipole modeling of spatio-temporal MEG (magnetoencephalogram) data

    SciTech Connect

    Mosher, J.C. . Systems Engineering and Development Div. University of Southern California, Los Angeles, CA . Signal and Image Processing Inst.); Lewis, P.S. ); Leahy, R. . Signal and Image Processing Inst.); Singh, M. (University of Southern Californi

    1990-01-01

    An array of SQUID biomagentometers may be used to measure the spatio-temporal neuromagnetic field produced by the brain in response to a given sensory stimulus. A popular model for the neural activity that produces these fields is a set of current dipoles. We present here a common linear algebraic framework for three common spatio-temporal dipole models: moving and rotating dipoles, rotating dipoles with fixed location, and dipoles with fixed orientation and location. Our intent here is not to argue the merits of one model over another, but rather show how each model may be solved efficiently, and within the same framework as the others. In all cases, we assume that the location, orientation, and magnitude of the dipoles are unknown. We present the parameter estimation problem for these three models in a common framework, and show how, in each case, the problem may be decomposed into the estimation of the dipole locations using nonlinear minimization followed by linear estimation of the associated moment time series. Numerically efficient means of calculating the cost function are presented, and problems of model order selection and missing moments are also investigated. The methods described are demonstrated in a simulated application to a three dipole problem. 21 refs., 2 figs., 1 tab.

  5. Diagnostics of the Fermilab Tevatron using an AC dipole

    SciTech Connect

    Miyamoto, Ryoichi

    2008-08-01

    The Fermilab Tevatron is currently the world's highest energy colliding beam facility. Its counter-rotating proton and antiproton beams collide at 2 TeV center-of-mass. Delivery of such intense beam fluxes to experiments has required improved knowledge of the Tevatron's beam optical lattice. An oscillating dipole magnet, referred to as an AC dipole, is one of such a tool to non-destructively assess the optical properties of the synchrotron. We discusses development of an AC dipole system for the Tevatron, a fast-oscillating (f ~ 20 kHz) dipole magnet which can be adiabatically turned on and off to establish sustained coherent oscillations of the beam particles without affecting the transverse emittance. By utilizing an existing magnet and a higher power audio amplifier, the cost of the Tevatron AC dipole system became relatively inexpensive. We discuss corrections which must be applied to the driven oscillation measurements to obtain the proper interpretation of beam optical parameters from AC dipole studies. After successful operations of the Tevatron AC dipole system, AC dipole systems, similar to that in the Tevatron, will be build for the CERN LHC. We present several measurements of linear optical parameters (beta function and phase advance) for the Tevatron, as well as studies of non-linear perturbations from sextupole and octupole elements.

  6. Measurement of coupling resonance driving terms with the AC dipole

    SciTech Connect

    Miyamoto, R.

    2010-10-01

    Resonance driving terms for linear coupled betatron motion in a synchrotron ring can be determined from corresponding spectral lines of an excited coherent beam motion. An AC dipole is one of instruments to excite such a motion. When a coherent motion is excited with an AC dipole, measured Courant-Snyder parameters and betatron phase advance have apparent modulations, as if there is an additional quadrupole field at the location of the AC dipole. Hence, measurements of these parameters using the AC dipole require a proper interpretation of observed quantities. The situation is similar in measurements of resonance driving terms using the AC dipole. In this note, we derive an expression of coupled betatron motion excited with two AC dipoles in presence of skew quadrupole fields, discuss an impact of this quadrupole like effect of the AC dipole on a measurement of coupling resonance driving terms, and present an analytical method to determine the coupling resonance driving terms from quantities observed using the AC dipole.

  7. Dipole collapse and reversal precursors in a numerical dynamo

    NASA Astrophysics Data System (ADS)

    Olson, Peter; Driscoll, Peter; Amit, Hagay

    2009-03-01

    Precursors to extreme geomagnetic field changes are examined in a numerical dynamo with a reversing dipolar magnetic field. A dynamo model with compositional convection in a rotating spherical shell produces a strongly dipolar external magnetic field over 6 Myr of simulated paleomagnetic time, with stable polarity epochs and occasional dipole collapses, some of which result in polarity reversals or dipole axis excursions. We analyze the model behavior during two dipole collapses, one that leads to a polarity reversal and one that does not, focusing on observable precursors. Reversed magnetic field induced in the dynamo interior by intermittent convective variability is the primary cause of dipole collapse. Spots of reversed magnetic flux emerge on the outer boundary at an early stage, then re-emerge with greater intensity at the height of the collapse. The energy in the external field cascades to higher harmonics as these reversed patches appear. Butterfly diagrams showing the reversed and normal flux contributions to the axial dipole reveal poleward migration of the patches during dipole collapse. Axial dipole reduction by precursory reversed flux is several times larger in the reversing case, compared to the non-reversing case. A butterfly diagram of the geomagnetic field since 1840 shows high latitude reversed flux emerging on the core-mantle boundary. Although the reversed geomagnetic flux is presently too weak to be labeled a reversal precursor, it is consistent with early stage dipole collapse in the dynamo model.

  8. Diagnostics of the Fermilab Tevatron using an AC dipole

    NASA Astrophysics Data System (ADS)

    Miyamoto, Ryoichi

    The Fermilab Tevatron is currently the world's highest energy colliding beam facility. Its counter-rotating proton and antiproton beams collide at 2 TeV center-of-mass. Delivery of such intense beam fluxes to experiments has required improved knowledge of the Tevatron's beam optical lattice. An oscillating dipole magnet, referred to as an AC dipole, is one of such a tool to non-destructively assess the optical properties of the synchrotron. We discusses development of an AC dipole system for the Tevatron, a fast-oscillating (f˜20 kHz) dipole magnet which can be adiabatically turned on and off to establish sustained coherent oscillations of the beam particles without affecting the transverse emittance. By utilizing an existing magnet and a higher power audio amplifier, the cost of the Tevatron AC dipole system became relatively inexpensive. We discuss corrections which must be applied to the driven oscillation measurements to obtain the proper interpretation of beam optical parameters from AC dipole studies. After successful operations of the Tevatron AC dipole system, AC dipole systems, similar to that in the Tevatron, will be build for the CERN LHC. We present several measurements of linear optical parameters (beta function and phase advance) for the Tevatron, as well as studies of non-linear perturbations from sextupole and octupole elements.

  9. Giant rockslides from the inside

    NASA Astrophysics Data System (ADS)

    Weidinger, Johannes T.; Korup, Oliver; Munack, Henry; Altenberger, Uwe; Dunning, Stuart A.; Tippelt, Gerold; Lottermoser, Werner

    2014-03-01

    The growing body of research on large-scale mass wasting events so far has only scarcely investigated the sedimentology of chaotic deposits from non-volcanic terrestrial landslides such that any overarching and systematic terminological framework remains elusive. Yet recent work has emphasized the need for better understanding the internal structure and composition of rockslide deposits as a means to characterise the mechanics during the final stages of runout and emplacement. We offer a comprehensive overview on the occurrence of rock fragmentation and frictional melt both at different geographic locations, and different sections within large (>106 m) rockslide masses. We argue that exposures of pervasively fragmented and interlocked jigsaw-cracked rock masses; basal mélange containing rip-up clasts and phantom blocks; micro-breccia; and thin bands of basal frictionite are indispensable clues for identifying deposits from giant rockslides that may remain morphologically inconspicuous otherwise. These sedimentary assemblages are diagnostic tools for distinguishing large rockslide debris from macro- and microscopically similar glacial deposits, tectonic fault-zone breccias, and impact breccias, and thus help avoid palaeoclimatic and tectonic misinterpretations, let alone misestimates of the hazard from giant rockslides. Moreover, experimental results from Mössbauer spectroscopy of frictionite samples support visual interpretations of thin sections, and demonstrate that short-lived (<10 s) friction-induced partial melting at temperatures >1500 °C in the absence of water occurred at the base of several giant moving rockslides. This finding supports previous theories of dry excess runout accompanied by comminution of rock masses down to μm-scale, and indicates that catastrophic motion of large fragmenting rock masses does not require water as a potential lubricant.

  10. Simulations of the angular dependence of the dipole-dipole interaction among Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Bigelow, Jacob L.; Hollingsworth, Jacob; Paul, Jacob T.; Peleg, Matan; Sanford, Veronica L.; Carroll, Thomas J.; Noel, Michael W.

    2016-05-01

    The dipole-dipole interaction between two Rydberg atoms depends on the relative orientation of the atoms and on the change in the magnetic quantum number. We simulate the effect of this anisotropy on the energy transport in an amorphous many atom system of ultracold Rydberg atoms subject to a homogeneous applied electric field. We consider two experimentally feasible geometries and find that the effects should be measurable in current generation imaging experiments. We also examine evidence for Anderson localization. This work was supported by the National Science Foundation under Grants No. 1205895 and No. 1205897 and used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation Grant Number OCI-1053575.

  11. Resonant electric dipole-dipole interactions between cold Rydberg atoms in a magnetic field

    NASA Astrophysics Data System (ADS)

    Afrousheh, Kourosh; Bohlouli-Zanjani, Parisa; Carter, Jeffery; Mugford, Ashton; Martin, James D. D.

    2006-05-01

    Laser cooled Rb atoms were optically excited to 46d5/2 Rydberg states. A microwave pulse transferred a fraction of the atoms to the 47p3/2 Rydberg state. The resonant electric dipole-dipole interactions between atoms in these two states were probed using the linewidth of the two-photon microwave transitions 46d5/2 -- 47d5/2. The presence of a weak magnetic field (roughly 1 G) reduced the observed line broadening, indicating that the interaction is suppressed by the field. The field removes some of the energy degeneracies responsible foe the resonant interaction, and this is the basis for a quantitative model of the resulting suppression. A technique for the calibration of magnetic field strengths using the 34s1/2 -- 34p1/2 one-photon transition is also presented.

  12. Resonant electric dipole-dipole interactions between cold Rydberg atoms in a magnetic field

    NASA Astrophysics Data System (ADS)

    Afrousheh, K.; Bohlouli-Zanjani, P.; Carter, J. D.; Mugford, A.; Martin, J. D. D.

    2006-06-01

    Laser-cooled Rb85 atoms were optically excited to 46d5/2 Rydberg states. A microwave pulse transferred a fraction of the atoms to the 47p3/2 Rydberg state. The resonant electric dipole-dipole interactions between atoms in these two states were probed using the linewidth of the two-photon microwave transition 46d5/2-47d5/2 . The presence of a weak magnetic field ≈0.5G reduced the observed line broadening, indicating that the interaction is suppressed by the field. The field removes some of the energy degeneracies responsible for the resonant interaction, and this is the basis for a quantitative model of the resulting suppression. A technique for the calibration of magnetic field strengths using the 34s1/2-34p1/2 one-photon transition is also presented.

  13. Controlling the dipole-dipole interaction using NMR composite rf pulses

    SciTech Connect

    Baudin, Emmanuel

    2014-08-07

    New composite rf pulses are proposed during which the average dipole-dipole interactions within a spin ensemble are controlled, while a global rotation is achieved. The method used to tailor the pulses is based on the average Hamiltonian theory and relies on the geometrical properties of the spin-spin dipolar interaction. I describe several such composite pulses and analyze quantitatively the improvement brought on the control of the NMR dynamics. Numerical simulations show that the magic sandwich pulse sequence, during which the average dipolar field is effectively reversed, is plagued by defects originating from the finite initial and final π/2 rf pulses. A numerical test based on a classical description of nuclear magnetic resonance is used to check that, when these pulses are replaced by magic composite pulses, the efficiency of the magic sandwich is improved.

  14. Quantum defect theory for the van der Waals plus dipole-dipole interaction

    NASA Astrophysics Data System (ADS)

    Wang, Gao-Ren; Xie, Ting; Huang, Yin; Zhang, Wei; Cong, Shu-Lin

    2012-12-01

    We investigate the scattering dynamics governed by the long-range van der Waals plus dipole-dipole interaction potential, -C6/R6-C3/R3, which describes the long-range interaction between two polar molecules in an electric field. In the spirit of quantum defect theory, a set of parameters which are nearly constants in the threshold regime is defined to characterize the scattering process. Using appropriate boundary conditions for the scattering wave functions and relevant parameters, we explore the quantum reflection by and quantum tunneling through the long-range potential. As a sample application, the reactive collision rates of 40K87Rb + 40K87Rb are calculated.

  15. Effect of resonance dipole-dipole interaction on spectra of adsorbed SF6 molecules.

    PubMed

    Dobrotvorskaia, Anna N; Kolomiitsova, Tatiana D; Petrov, Sergey N; Shchepkin, Dmitriy N; Smirnov, Konstantin S; Tsyganenko, Alexey A

    2015-09-01

    Adsorption of SF6 on zinc oxide and on silicalite-1 was investigated by a combination of IR spectroscopy with the calculations of spectra by means of a modernized model, developed previously for liquids. Comparison of the experimental spectra and the results of modeling shows that the complex band shapes in spectra of adsorbed molecules with extremely high absorbance are due to the strong resonance dipole-dipole interaction (RDDI) rather that the surface heterogeneity or the presence of specific surface sites. Perfect agreement between calculated and observed spectra was found for ZnO, while some dissimilarity in band intensities for silicalite-1 was attributed to complicated geometry of molecular arrangement in the channels. PMID:25897721

  16. Giant Piloleiomyoma of the Forehead

    PubMed Central

    Kim, Gun-Wook; Park, Hyun-Je; Kim, Hoon-Soo; Kim, Su-Han; Ko, Hyun-Chang; Kim, Byung-Soo

    2011-01-01

    Cutaneous piloleiomyomas are benign smooth muscle tumors arising from the arrector pili muscles. Piloleiomyomas appear as firm dermal papules of skin color or with a reddish to brown surface, and are commonly located on the extremities. Histologically, these lesions are composed of interlacing bundles of smooth muscle cells in the reticular dermis. Our case presented with an unusually large nodule on the forehead that was accompanied by intermittent pain. Histological analysis was compatible with piloleiomyoma and the lesion showed haphazardly arranged bundles of smooth muscle in the dermis. We describe herein an interesting case of a giant piloleiomyoma occurring on the forehead. PMID:22148036

  17. [Aortitis in giant cell arteritis].

    PubMed

    Schmidt, J; Duhaut, P

    2016-04-01

    Aortitis is a frequent complication of giant cell arteritis. Imaging techniques can reveal the inflammation of the aortic wall. CT-scan can show circumferential aortic wall thickening, or TEP-scan can show aortic FDG-uptake. Aortic aneurysm and dissection is a feared but probably rare complication of the inflammation of the aortic wall during GCA. Screening for aortitis could be proposed for patients with symptoms of aortic involvement, for patients with signs of large vessels involvement (limb claudication, bruit) or for patients with incomplete response to treatment. The best follow-up and treatment are to be determined for the patients with aortitis related to GCA. PMID:26781692

  18. Wideband dipole antenna with inter-digital capacitor

    NASA Astrophysics Data System (ADS)

    Xiong, Han; Hong, Jin-Song; Jin, Da-Lin

    2013-04-01

    A dipole antenna with wideband characteristics is presented. The proposed antenna consists of a dipole with periodic capacitive loading and a pair of coplanar striplines (CPSs) as an impedance transformer. By adding interlaced coupling lines at each section, periodic capacitive loading is realized. The periodic interlaced coupling lines divide each arm of the dipole into five sections, and currents are distributed on different sections at different frequencies, which is useful to achieve a wide impedance bandwidth. By parametric study using HFSS, the optimized parameters of this dipole antenna are obtained. In order to validate the simulation results, a prototype of the proposed dipole antenna is fabricated and tested. The results show that the proposed antenna can achieve a gain of 3.1 dB-5.1 dB and bandwidth of 51% for |S11| < -10 dB over the band of 3.9 GHz-6.6 GHz, indicating its good radiation performance and radiation efficiency.

  19. Mesogen polarity effects on biaxial nematics. Centrally located dipoles.

    PubMed

    Querciagrossa, Lara; Ricci, Matteo; Berardi, Roberto; Zannoni, Claudio

    2013-11-21

    We investigate the phase organisation of thermotropic biaxial Gay-Berne (GB) mesogens yielding a biaxial nematic (Nb) phase upon endowing them with a central point dipole. We study the effects of changing the strength and orientation of the dipole on the phase behaviour, and in particular we examine, using molecular dynamics (MD) simulations, the possibility of improving the stability of the Nb phase. After mapping the boundaries of the Nb phase, we find that the strength of the embedded dipole is the parameter with the strongest influence on the mesogenic properties, while its orientation plays a minor role. For these central dipole systems, we find that the Nb phase organisation is stable only for mesogens with relatively weak dipole moments, while it disappears if electrostatic interactions become comparable in magnitude with dispersion interactions. PMID:24100468

  20. Dipole splitting algorithm: A practical algorithm to use the dipole subtraction procedure

    NASA Astrophysics Data System (ADS)

    Hasegawa, K.

    2015-11-01

    The Catani-Seymour dipole subtraction is a general and powerful procedure to calculate the QCD next-to-leading order corrections for collider observables. We clearly define a practical algorithm to use the dipole subtraction. The algorithm is called the dipole splitting algorithm (DSA). The DSA is applied to an arbitrary process by following well defined steps. The subtraction terms created by the DSA can be summarized in a compact form by tables. We present a template for the summary tables. One advantage of the DSA is to allow a straightforward algorithm to prove the consistency relation of all the subtraction terms. The proof algorithm is presented in the following paper [K. Hasegawa, arXiv:1409.4174]. We demonstrate the DSA in two collider processes, pp to μ -μ + and 2 jets. Further, as a confirmation of the DSA, it is shown that the analytical results obtained by the DSA in the Drell-Yan process exactly agree with the well known results obtained by the traditional method.

  1. Universal Behavior of Dielectric Responses of Glass Formers: Role of Dipole-Dipole Interactions.

    PubMed

    Paluch, M; Knapik, J; Wojnarowska, Z; Grzybowski, A; Ngai, K L

    2016-01-15

    From an exhaustive examination of the molecular dynamics in practically all van der Waals molecular glass formers ever probed by dielectric spectroscopy, we found that the width of the α-loss peak at or near the glass transition temperature T_{g} is strongly anticorrelated with the polarity of the molecule. The larger the dielectric relaxation strength Δε(T_{g}) of the system, the narrower is the α-loss peak. This remarkable property is explained by the contribution from the dipole-dipole interaction potential V_{dd}(r)=-Dr^{-6} to the attractive part of the intermolecular potential, making the resultant potential more harmonic, and the effect increases rapidly with the dipole moment μ and Δε(T_{g}) in view of the relation, D∝(μ^{4}/kT_{g})∝kT_{g}[Δε(T_{g})]^{2}. Since the novel correlation discovered encompasses practically all van der Waals molecular glass formers studied by dielectric spectroscopy, it impacts the large dielectric research community as well as those engaged in solving the glass transition problem. PMID:26824551

  2. Universal Behavior of Dielectric Responses of Glass Formers: Role of Dipole-Dipole Interactions

    NASA Astrophysics Data System (ADS)

    Paluch, M.; Knapik, J.; Wojnarowska, Z.; Grzybowski, A.; Ngai, K. L.

    2016-01-01

    From an exhaustive examination of the molecular dynamics in practically all van der Waals molecular glass formers ever probed by dielectric spectroscopy, we found that the width of the α -loss peak at or near the glass transition temperature Tg is strongly anticorrelated with the polarity of the molecule. The larger the dielectric relaxation strength Δ ɛ (Tg) of the system, the narrower is the α -loss peak. This remarkable property is explained by the contribution from the dipole-dipole interaction potential Vd d(r )=-D r-6 to the attractive part of the intermolecular potential, making the resultant potential more harmonic, and the effect increases rapidly with the dipole moment μ and Δ ɛ (Tg) in view of the relation, D ∝(μ4/k Tg)∝k Tg[Δɛ (Tg)] 2 . Since the novel correlation discovered encompasses practically all van der Waals molecular glass formers studied by dielectric spectroscopy, it impacts the large dielectric research community as well as those engaged in solving the glass transition problem.

  3. Dipole-Dipole Interactions of High-spin Paramagnetic Centers in Disordered Systems

    SciTech Connect

    Maryasov, Alexander G.; Bowman, Michael K.; Tsvetkov, Yuri D.

    2007-09-13

    Dipole-dipole interactions between distant paramagnetic centers (PCs) where at least one PC has spin S>1/2 are examined. The results provide a basis for the application of pulsed DEER or PELDOR methods to the measurement of distances between PC involving high-spin species. A projection operator technique based on spectral decomposition of the secular Hamiltonian is used to calculate EPR line splitting caused by the dipole coupling. This allows calculation of operators projecting arbitrary wavefunction onto high PC eigenstates when the eigenvectors of the Hamiltonian are not known. The effective spin vectors-that is, the expectation values for vector spin operators in the PC eigenstates-are calculated. The dependence of these effective spin vectors on the external magnetic field is calculated. There is a qualitative difference between pairs having at least one integer spin (non Karmers PC) and pairs of two half-integer (Kramers PC) spins. With the help of these effective spin vectors, the dipolar lineshape of EPR lines is calculated. Analytical relations are obtained for PCs with spin S=1/2 and 1. The dependence of Pake patterns on variations of zero field splitting, Zeeman energy, temperature and dipolar coupling are illustrated.

  4. Bilateral giant cyst of the shoulder.

    PubMed

    Agarwal, A; Ferrante, J; Schmidt, R; Eisenbeis, C H

    1987-01-01

    The case of a 61 year old white female with a rapidly progressive rheumatoid arthritis who developed bilateral giant cyst of the shoulder is described here. Arthrographic investigation indicated that these giant cysts were true synovial cysts rather than "pseudocysts". PMID:3427842

  5. Dipole-dipole interactions in solution mixtures probed by two-dimensional synchronous spectroscopy based on orthogonal sample design scheme.

    PubMed

    Li, Hui-zhen; Tao, Dong-liang; Qi, Jian; Wu, Jin-guang; Xu, Yi-zhuang; Noda, Isao

    2014-04-24

    Two-dimensional (2D) synchronous spectroscopy together with a new approach called "Orthogonal Sample Design Scheme" was used to study the dipole-dipole interactions in two representative ternary chemical systems (N,N-dimethyllformamide (DMF)/CH3COOC2H5/CCl4 and C60/CH3COOC2H5/CCl4). For the first system, dipole-dipole interactions among carbonyl groups from DMF and CH3COOC2H5 are characterized by using the cross peak in 2D Fourier Transform Infrared Radiation (FT-IR) spectroscopy. For the second system, intermolecular interaction among π-π transition from C60 and vibration transition from the carbonyl band of ethyl acetate is probed by using 2D spectra. The experimental results demonstrate that "Orthogonal Sample Design Scheme" can effectively remove interfering part that is not relevant to intermolecular interaction. Additional procedures are carried out to preclude the possibilities of producing interfering cross peaks by other reasons, such as experimental errors. Dipole-dipole interactions that manifest in the form of deviation from the Beer-Lambert law generate distinct cross peaks visualized in the resultant 2D synchronous spectra of the two chemical systems. This work demonstrates that 2D synchronous spectra coupled with orthogonal sample design scheme provide us an applicable experimental approach to probing and characterizing dipole-dipole interactions in complex molecular systems. PMID:24582337

  6. Sodium in weak G-band giants

    NASA Technical Reports Server (NTRS)

    Drake, Jeremy J.; Lambert, David L.

    1994-01-01

    Sodium abundances have been determined for eight weak G-band giants whose atmospheres are greatly enriched with products of the CN-cycling H-burning reactions. Systematic errors are minimized by comparing the weak G-band giants to a sample of similar but normal giants. If, further, Ca is selected as a reference element, model atmosphere-related errors should largely be removed. For the weak-G-band stars (Na/Ca) = 0.16 +/- 0.01, which is just possibly greater than the result (Na/Ca) = 0.10 /- 0.03 from the normal giants. This result demonstrates that the atmospheres of the weak G-band giants are not seriously contaminated with products of ON cycling.

  7. ASTEROSEISMIC CLASSIFICATION OF STELLAR POPULATIONS AMONG 13,000 RED GIANTS OBSERVED BY KEPLER

    SciTech Connect

    Stello, Dennis; Bedding, Timothy R.; Benomar, Othman; White, Timothy R.; Huber, Daniel; Bildsten, Lars; Paxton, Bill; Elsworth, Yvonne P.; Gilliland, Ronald L.; Mosser, Benoit

    2013-03-10

    Of the more than 150,000 targets followed by the Kepler Mission, about 10% were selected as red giants. Due to their high scientific value, in particular for Galaxy population studies and stellar structure and evolution, their Kepler light curves were made public in late 2011. More than 13,000 (over 85%) of these stars show intrinsic flux variability caused by solar-like oscillations making them ideal for large-scale asteroseismic investigations. We automatically extracted individual frequencies and measured the period spacings of the dipole modes in nearly every red giant. These measurements naturally classify the stars into various populations, such as the red giant branch, the low-mass (M/M{sub Sun} {approx}< 1.8) helium-core-burning red clump, and the higher-mass (M/M{sub Sun} {approx}> 1.8) secondary clump. The period spacings also reveal that a large fraction of the stars show rotationally induced frequency splittings. This sample of stars will undoubtedly provide an extremely valuable source for studying the stellar population in the direction of the Kepler field, in particular when combined with complementary spectroscopic surveys.

  8. Deep Imaging of Giant Planets

    NASA Astrophysics Data System (ADS)

    Chauvin, G.

    2010-10-01

    With the development of high contrast imaging instruments and techniques, vast efforts have been devoted during the past decade to detect and characterize lighter, cooler and closer companions to nearby stars, and ultimately image new planetary systems. Complementary to other observing techniques (radial velocity, transit, micro-lensing, pulsar-timing and astrometry), this approach has opened a new astrophysical window to study the physical properties and the formation and evolution mechanisms of giant planets at orbits larger than a few AUs. In this review, I will briefly present the main motivations to use deep imaging to search for exoplanets and review the constant progress achieved thanks to improved performances of advanced instrumentation and data analysis techniques. I will describe the main classes of stars identified and observed so far to increase the chances of detection. I will also detail the classical strategy adopted to identify false alarms and characterize true companions. I will review the current status of the different deep imaging surveys as well as the main results that recently led to the discovery of giant planets probably formed like the ones of our solar system. Finally, I will rise the questions and uncertainties related to the formation mechanisms, the physical properties and the frequency of these planetary mass companions to conclude with the exciting and attractive perspectives offered with the future generation of deep imaging instruments.

  9. Giant Planets in Open Clusters

    NASA Astrophysics Data System (ADS)

    Quinn, S. N.; White, R. J.; Latham, D. W.

    2015-10-01

    Two decades after the discovery of 51 Peg b, more than 200 hot Jupiters have now been confirmed, but the details of their inward migration remain uncertain. While it is widely accepted that short period giant planets could not have formed in situ, several different mechanisms (e.g., Type II migration, planet-planet scattering, Kozai-Lidov cycles) may contribute to shrinking planetary orbits, and the relative importance of each is not well-constrained. Migration through the gas disk is expected to preserve circular, coplanar orbits and must occur quickly (within ˜ 10 Myr), whereas multi-body processes should initially excite eccentricities and inclinations and may take hundreds of millions of years. Subsequent evolution of the system (e.g., orbital circularization and inclination damping via tidal interaction with the host star) may obscure these differences, so observing hot Jupiters soon after migration occurs can constrain the importance of each mechanism. Fortunately, the well-characterized stars in young and adolescent open clusters (with known ages and compositions) provide natural laboratories for such studies, and recent surveys have begun to take advantage of this opportunity. We present a review of the discoveries in this emerging realm of exoplanet science, discuss the constraints they provide for giant planet formation and migration, and reflect on the future direction of the field.

  10. Two Giant Planets Orbiting the K Giant Star η Cet

    NASA Astrophysics Data System (ADS)

    Trifonov, T.; Reffert, S.; Tan, X.; Lee, M. H.; Quirrenbach, A.

    2014-01-01

    We present evidence of a new planetary system around the K giant η Cet (HIP 5364, HD 6805, HR 334), based on 124 high-precision optical and infrared radial velocity data, taken at Lick Observatory (Hamilton) and at VLT (CRIRES). The best dynamical fit to the data is consistent with two massive planets (m 1sini~2.6M Jup , m 2sini~3.3MJup ) and with periods of P 1~407 days, P 2~740 days. To test the η Cet system's stability we perform ~ 10,000 dynamical investigations with maximum time spans of 108 years. We find that in case of moderate eccentricities, the planets can be effectively trapped in an anti-aligned stable 2:1 mean motion resonance (MMR), very close to the separatrix. A larger non-resonant stable region exists in low-eccentricity parameter space, although less probable than the 2:1 MMR region.

  11. Geomagnetic dipole moment collapse by convective mixing in the core

    NASA Astrophysics Data System (ADS)

    Liu, Lijun; Olson, Peter

    2009-05-01

    Convective mixing in the fluid outer core can induce rapid transient decrease of the geomagnetic dipole. Here we determine rates of dipole moment decrease as a function of magnetic Reynolds number following convective instability in a numerical dynamo and in axisymmetric kinematic flows. Our calculations show that mixing flows induce reversed magnetic flux on the core-mantle boundary through expulsion of mostly poloidal magnetic field by convective upwellings. The dipole field collapse is accelerated by enhanced radial diffusion and meridional advection of magnetic flux below the core-mantle boundary. Magnetic energy cascades from the dipole to smaller scales during mixing, producing a filamentary magnetic field structure on the core-mantle boundary. We find that the maximum rate of dipole moment decrease on century time scales is weakly sensitive to the mixing flow pattern but varies with the velocity of the flow approximately as cRm β , with Rm the magnetic Reynolds number and (c, β) ≈ (0.2 ± 0.07, 0.78 ± 0.05). According to our calculations, a mixing flow in the outer core with Rm in the range of 200-300 can account for the historically-measured rate of decrease of the geomagnetic dipole moment, although it is unlikely that a single mixing flow event with this intensity would cause a full dipole collapse or polarity reversal.

  12. An integrated giant magnetoimpedance biosensor for detection of biomarker.

    PubMed

    Wang, Tao; Yang, Zhen; Lei, Chong; Lei, Jian; Zhou, Yong

    2014-08-15

    A Dynabeads-labeled magnetic immunoassay (MIA) has been developed by using an integrated giant magnetoimpedance (GMI) biosensor for the detection of alpha-fetoprotein (AFP). The GMI biosensor (Cr/Cu/NiFe/Cu/NiFe/Al2O3/Cr/Au films) integrated magnetic sensing elements and a biomolecular immunoplatform. Au film was modified with 11-Mercaptoundecanoic acid (11-MUA) for the immobilization of AFP monoclonal antibody. Double antibody sandwich immunoassay was used to specifically capture and label AFP antigen. Functionalized Dynabeads were conjugated to AFP antigen by streptavidin-biotin binding assay. GMI responses were measured for sensitive detection of AFP from 1 to 10ng/ml. Our results revealed that the presence of AFP on the biosensor improved the GMI effect owing to the induced magnetic dipole of superparamagnetic Dynabeads, and the GMI ratio was greatly increased at high frequency. Specificity of MIA was tested through the use of 1% bovine serum albumin (BSA). The underlying biophysical mechanisms responsible for the enhanced GMI effect in the detection of AFP were discussed. This work provides a complex lab-on-chip MIA for the detection of biomarker, which may open up a new way for the development of GMI-based MIA in clinical trials. PMID:24662064

  13. NLO evolution of color dipoles in N=4 SYM

    SciTech Connect

    Chirilli, Giovanni A.; Balitsky, Ian

    2009-07-04

    Here, high-energy behavior of amplitudes in a gauge theory can be reformulated in terms of the evolution of Wilson-line operators. In the leading logarithmic approximation it is given by the conformally invariant BK equation for the evolution of color dipoles. In QCD, the next-to-leading order BK equation has both conformal and non-conformal parts, the latter providing the running of the coupling constant. To separate the conformally invariant effects from the running-coupling effects, we calculate the NLO evolution of the color dipoles in the conformal ${\\cal N}$=4 SYM theory. We define the "composite dipole operator" with the rapidity cutoff preserving conformal invariance.

  14. CONSTRAINT ON LIGHT DIPOLE DARK MATTER FROM HELIOSEISMOLOGY

    SciTech Connect

    Lopes, Ilídio; Kadota, Kenji; Silk, Joseph E-mail: ilopes@uevora.pt E-mail: silk@astro.ox.ac.uk

    2014-01-10

    We investigate the effects of a magnetic dipole moment of asymmetric dark matter (DM) in the evolution of the Sun. The dipole interaction can lead to a sizable DM scattering cross section even for light DM, and asymmetric DM can lead to a large DM number density in the Sun. We find that solar model precision tests, using as diagnostic the sound speed profile obtained from helioseismology data, exclude dipolar DM particles with a mass larger than 4.3 GeV and magnetic dipole moment larger than 1.6 × 10{sup –17} e cm.

  15. Propagation of the Lissajous singularity dipole in free space

    NASA Astrophysics Data System (ADS)

    Chen, Haitao; Gao, Zenghui; Zou, Xuefang; Xiao, Xi; Wang, Fanhou; Yang, Huajun

    2014-01-01

    The propagation properties of a pair of Lissajous singularities with opposite singularity indexes called the Lissajous singularity dipole (LSD) in free space are studied analytically and illustrated numerically. It is shown that the motion, creation, annihilation and change in the degree of polarization of the LSD, and change in the shape of Lissajous figures take place by suitably varying the waist width, off-axis distance or propagation distance. In particular, the creation and shift to infinity of a single Lissajous singularity may appear. A comparison with the free-space propagation of an optical vortex dipole and a C-dipole is also made.

  16. Diatomic molecules in optical and microwave dipole traps

    SciTech Connect

    Lysebo, Marius; Veseth, Leif

    2011-03-15

    The dipole forces on rotating diatomic molecules are worked out in detail for optical as well as microwave radiation fields. The objective is in particular to investigate how the dipole forces and potentials depend on the subtle internal structure of the molecule, with special emphasis on hyperfine and Zeeman states. Dipole potentials are obtained from computations of the real part of the complex molecular polarizability, whereas the imaginary part yields the scattering force. Numerical examples are presented for {sup 23}Na{sub 2} and OH for optical (laser) fields related to strong electronic transitions and for microwave fields for the {Lambda} doubling in the OH ground state.

  17. Equipotential transformation of multipole systems to dipole systems

    NASA Technical Reports Server (NTRS)

    Wang, W. X.

    1987-01-01

    The vector sum of fields produced by a set of magnetic dipoles with different magnetic moments that are both tilted from the planetary spin axis and offset from the planetary center by different amounts can be used to completely represent a planetary magnetic field in the conventional form of spherical harmonic expansion. The scalar equipotential transformation analytically results in 24 equations that may subsequently be solved for the 24 adjustable parameters in dipole systems with the predetermined main dipole. Attention is given to this method's application to the Jovian magnetic field.

  18. Nuclear Electric Dipole Moment of 3He

    SciTech Connect

    Stetcu, I; P.Liu, C; Friar, J L; Hayes, A C; Navratil, P

    2008-04-08

    A permanent electric dipole moment (EDM) of a physical system would require time-reversal (T) violation, which is equivalent to charge-conjugation-parity (CP) violation by CPT invariance. Experimental programs are currently pushing the limits on EDMs in atoms, nuclei, and the neutron to regimes of fundamental theoretical interest. Nuclear EDMs can be studied at ion storage rings with sensitivities that may be competitive with atomic and neutron measurements. Here we calculate the magnitude of the CP-violating EDM of {sup 3}He and the expected sensitivity of such a measurement to the underlying CP-violating interactions. Assuming that the coupling constants are of comparable magnitude for {pi}-, {rho}-, and {omega}-exchanges, we find that the pion-exchange contribution dominates. Finally, our results suggest that a measurement of the {sup 3}He EDM is complementary to the planned neutron and deuteron experiments, and could provide a powerful constraint for the theoretical models of the pion-nucleon P,T-violating interaction.

  19. An Efficient Coupled Dipole Method: TCDM

    NASA Astrophysics Data System (ADS)

    Kim, Hye-Young

    2015-03-01

    An overview of a memory-efficient and cost-effective method, called Trace-Coupled Dipole Method (TCDM), which can accurately predict the van der Waals (VDW) forces between dielectric materials will be presented. CDM is an intrinsically atomistic method which includes all the many-body interaction terms self-consistently. TCDM, an alternative way to execute CDM, is to obtain VDW interaction energy by calculating the trace of a 3NX3N matrix, rather than its eigenvalues. It will be demonstrated that the power series expansion in TCDM is equivalent to that of the perturbation theory. The advantage of adopting TCDM over the conventional perturbation theory or CDM will also be discussed. The use of TCDM will make it practical for any interested future users to calculate the accurate VDW interaction in large systems like those found in computer simulation studies without serious increase in computational burden. This research is supported by the Louisiana Board of Regents-RCS Grant (LEQSF(2012-15)-RD-A-19).

  20. Magnetic dipole discharges. I. Basic properties

    SciTech Connect

    Stenzel, R. L.; Urrutia, J. M.; Teodorescu-Soare, C. T.; Ionita, C.; Schrittwieser, R.

    2013-08-15

    A simple discharge is described which uses a permanent magnet as a cold cathode and the metallic chamber wall as an anode. The magnet's equator is biased strongly negative, which produces secondary electrons due to the impact of energetic ions. The emitted electrons are highly confined by the strong dipolar magnetic field and the negative potential in the equatorial plane of the magnet. The emitted electrons ionize near the sheath and produce further electrons, which drift across field lines to the anode while the nearly unmagnetized ions are accelerated back to the magnet. A steady state discharge is maintained at neutral pressures above 10{sup −3} mbar. This is the principle of magnetron discharges, which commonly use cylindrical and planar cathodes rather than magnetic dipoles as cathodes. The discharge properties have been investigated in steady state and pulsed mode. Different magnets and geometries have been employed. The role of a background plasma has been investigated. Various types of instabilities have been observed such as sheath oscillations, current-driven turbulence, relaxation instabilities due to ionization, and high frequency oscillations created by sputtering impulses, which are described in more detail in companion papers. The discharge has also been operated in reactive gases and shown to be useful for sputtering applications.

  1. Electric dipole polarizability and the neutral skin

    SciTech Connect

    Piechaczek, A.; Nazarewicz, Witold; Reinhard, P.-G.; Agrawal, Bijay K; Colo, Gianluca; Paar, Nils; Roca-Maza, X; Vretenar, Dario

    2012-01-01

    The recent high-resolution measurement of the electric dipole (E1) polarizability {alpha}{sub D} in {sup 208}Pb [A. Tamii et al. Phys. Rev. Lett. 107 062502 (2011)] provides a unique constraint on the neutron-skin thickness of this nucleus. The neutron-skin thickness r{sub skin} of {sup 208}Pb is a quantity of critical importance for our understanding of a variety of nuclear and astrophysical phenomena. To assess the model dependence of the correlation between {alpha}{sub D} and r{sub skin}, we carry out systematic calculations for {sup 208}Pb, {sup 132}Sn, and {sup 48}Ca based on the nuclear density functional theory using both nonrelativistic and relativistic energy density functionals. Our analysis indicates that whereas individual models exhibit a linear dependence between {alpha}{sub D} and r{sub skin}, this correlation is not universal when one combines predictions from a host of different models. By averaging over these model predictions, we provide estimates with associated systematic errors for r{sub skin} and {alpha}{sub D} for the nuclei under consideration. We conclude that precise measurements of r{sub skin} in both {sup 48}Ca and {sup 208}Pb - combined with the recent measurement of {alpha}{sub D} - should significantly constrain the isovector sector of the nuclear energy density functional.

  2. Two flavors of the Indian Ocean Dipole

    NASA Astrophysics Data System (ADS)

    Endo, Satoru; Tozuka, Tomoki

    2015-07-01

    The Indian Ocean Dipole (IOD) is known as a climate mode in the tropical Indian Ocean accompanied by negative (positive) sea surface temperature (SST) anomalies over the eastern (western) pole during its positive phase. However, the western pole of the IOD is not always covered totally by positive SST anomalies. For this reason, the IOD is further classified into two types in this study based on SST anomalies in the western pole. The first type (hereafter "canonical IOD") is associated with negative (positive) SST anomalies in the eastern (central to western) tropical Indian Ocean. The second type (hereafter "IOD Modoki"), on the other hand, is associated with negative SST anomalies in the eastern and western tropical Indian Ocean and positive SST anomalies in the central tropical Indian Ocean. Based on composite analyses, it is found that easterly wind anomalies cover the whole equatorial Indian Ocean in the canonical IOD, and as a result, positive rainfall anomalies are observed over East Africa. Also, due to the basin-wide easterly wind anomalies, the canonical IOD is accompanied by strong sea surface height (SSH) anomalies. In contrast, zonal wind anomalies converge in the central tropical Indian Ocean in the IOD Modoki, and no significant precipitation anomalies are found over East Africa. Also, only weak SSH anomalies are seen, because equatorial downwelling anomalies induced by westerly wind anomalies in the west are counteracted by equatorial upwelling anomalies caused by easterly wind anomalies in the east.

  3. Presheaths in multi-dipole plasma

    SciTech Connect

    Hala, A.M.; Hershkowitz, N.

    1998-12-31

    Measurements of plasma presheath thickness as a function of pressure (0.5 to 2 mTorr) were made in a DC hot-filament produced multi-dipole plasma discharge. The presheath plasma potential near a negatively biased plate (D = 10 cm) was mapped with an emissive probe. The inflection point method in the limit of zero emission was used. The probe measurement of the plasma potential were accurate to approximately 0.1 V. Measurements were made in plasmas based on nitrogen, argon and combinations of both gases. Experimental results were similar to those found in ECR magnetized plasmas. The presheaths were found to be regions of approximately constant electric field with characteristic lengths the order of the ion-neutral collision lengths. The results show contraction of the presheath as the pressure increased. Two competing processes affect the presheath. These are ionization and collisions with ionization becoming more important at lower pressures. Experimental results are compared to various presheath models.

  4. The search for permanent electric dipole moments

    SciTech Connect

    Kirch, Klaus

    2013-02-13

    Permanent electric dipole moments (EDMs) of fundamental systems with spin - particles, nuclei, atoms or molecules violate parity and time reversal invariance. Invoking the CPT theorem, time reversal violation implies CP violation. Although CP-violation is implemented in the standard electro-weak theory, EDM generated this way remain undetectably small. However, this CP-violation also appears to fail explaining the observed baryon asymmetry of our universe. Extensions of the standard theory usually include new sources of CP violation and often predict sizeable EDMs. EDM searches in different systems are complementary and various efforts worldwide are underway and no finite value has been established yet. The prototype of an EDM search is the pursuit of the EDM of the neutron. It has the longest history and at the same time is at the forefront of present research. The talk aims at giving an overview of the field with emphasis on our efforts within an international collaboration at PSI, nedm.web.psi.ch.

  5. Nuclear Electric Dipole Moment of ^{3}_He

    SciTech Connect

    Stetcu, I.; Liu, C.-P.; Friar, J. L.; Hayes, A. C.; Navratil, P.

    2008-01-01

    A permanent electric dipole moment (EDM) of a physical system would require time-reversal (T) violation, which is equivalent to charge-conjugation-parity (CP) violation by CPT invariance. Experimental programs are currently pushing the limits on EDMs in atoms, nuclei, and the neutron to regimes of fundamental theoretical interest. Nuclear EDMs can be studied at ion storage rings with sensitivities that may be competitive with atomic and neutron measurements. Here we calculate the magnitude of the CP-violating EDM of ^{3}_He and the expected sensitivity of such a measurement to the underlyng CP-violating interactions. Assuming that the coupling constants are of comparable magnitude for {\\pi}-, {\\rho}-, and {\\omega}-exchanges, we find that the pion-exchange contribution dominates. Our results suggest that a measurement of the ^{3}_He EDM is complementary to the planned neutron and deuteron experiments, and could provide a powerful constraint for the theoretical models of the pion-nucleon P,T-violating interaction.

  6. Two flavors of the Indian Ocean Dipole

    NASA Astrophysics Data System (ADS)

    Endo, Satoru; Tozuka, Tomoki

    2016-06-01

    The Indian Ocean Dipole (IOD) is known as a climate mode in the tropical Indian Ocean accompanied by negative (positive) sea surface temperature (SST) anomalies over the eastern (western) pole during its positive phase. However, the western pole of the IOD is not always covered totally by positive SST anomalies. For this reason, the IOD is further classified into two types in this study based on SST anomalies in the western pole. The first type (hereafter "canonical IOD") is associated with negative (positive) SST anomalies in the eastern (central to western) tropical Indian Ocean. The second type (hereafter "IOD Modoki"), on the other hand, is associated with negative SST anomalies in the eastern and western tropical Indian Ocean and positive SST anomalies in the central tropical Indian Ocean. Based on composite analyses, it is found that easterly wind anomalies cover the whole equatorial Indian Ocean in the canonical IOD, and as a result, positive rainfall anomalies are observed over East Africa. Also, due to the basin-wide easterly wind anomalies, the canonical IOD is accompanied by strong sea surface height (SSH) anomalies. In contrast, zonal wind anomalies converge in the central tropical Indian Ocean in the IOD Modoki, and no significant precipitation anomalies are found over East Africa. Also, only weak SSH anomalies are seen, because equatorial downwelling anomalies induced by westerly wind anomalies in the west are counteracted by equatorial upwelling anomalies caused by easterly wind anomalies in the east.

  7. Giant tunneling magnetoresistance in silicene

    SciTech Connect

    Wang, Yu; Lou, Yiyi

    2013-11-14

    We have theoretically studied ballistic electron transport in silicene under the manipulation of a pair of ferromagnetic gate. Transport properties like transmission and conductance have been calculated by the standard transfer matrix method for parallel and antiparallel magnetization configurations. It is demonstrated here that, due to the stray field-induced wave-vector filtering effect, remarkable difference in configuration-dependent transport gives rise to a giant tunneling magnetoresistance. In combination with the peculiar buckled structure of silicene and its electric tunable energy gap, the receiving magnetoresistance can be efficiently modulated by the externally-tunable stray field, electrostatic potential, and staggered sublattice potential, providing some flexible strategies to construct silicene-based nanoelectronic device.

  8. Giant magnetoresistance in nanogranular magnets.

    SciTech Connect

    Glatz, A.; Beloborodov, I. S.; Vinokur, V. M.; Materials Science Division; Univ. of Chicago

    2008-05-01

    We study the giant magnetoresistance of nanogranular magnets in the presence of an external magnetic field and finite temperature. We show that the magnetization of arrays of nanogranular magnets has hysteretic behavior at low temperatures leading to a double peak in the magnetoresistance which coalesces at high temperatures into a single peak. We numerically calculate the magnetization of magnetic domains and the motion of domain walls in this system using a combined mean-field approach and a model for an elastic membrane moving in a random medium, respectively. From the obtained results, we calculate the electric resistivity as a function of magnetic field and temperature. Our findings show excellent agreement with various experimental data.

  9. The Giant Metrewave Radio Telescope

    NASA Astrophysics Data System (ADS)

    Nityananda, R.

    2003-05-01

    The Giant Metrewave Radio Telescope (GMRT) of the National Centre of Radio Astrophysics (NCRA) of the Tata Institute of Fundamental Research (TIFR) at Khodad, India, has been operational in the band 0.2 to 2 metres for the last two and a half years. The system characteristics and performance and recent results from the group will be presented. Details of use over the last six months by scientists from other observatories under the GMRT Time Allocation Committee (GTAC) and future plans will be also be reviewed in this paper. Areas which have been studied include observations made in the GMRT band of neutral hydrogen, nearby galaxies, supernova remnants, the Galactic Centre, pulsars, the Sun and others.

  10. The Chinese Giant Solar Telescope

    NASA Astrophysics Data System (ADS)

    Liu, Zhong; Deng, Yuanyong; Ji, Haisheng

    2014-01-01

    Chinese Giant Solar Telescope is the next generation ground-based solar telescope. The main science task of this telescope is to observe the ultra fine structures of the solar magnetic field and dynamic field. Due to the advantages in polarization detection and thermal controlling with a symmetrical circular system, the current design of CGST is a 6~8 meter circular symmetrical telescope. The results of simulations and analysis showed that the current design could meet the demands of most science cases not only in infrared bands but also in near infrared bands and even in visible bands. The prominences and the filaments are very important science cases of CGST. The special technologies for prominence observation will be developed, including the day time laser guide star and MCAO. CGST is proposed by all solar observatories and several institutes and universities in China. It is supported by CAS and NSFC (National Natural Science Foundation of China) as a long term astronomical project.

  11. Core formation by giant impacts

    NASA Technical Reports Server (NTRS)

    Tonks, W. B.; Melosh, H. J.

    1991-01-01

    Ideas about the accretion and early evolution of the Earth and the other terrestrial planets have recently undergone a number of revolutionary changes. It has become clear that giant impacts were far from rare events. In the later stages of accretion any given planetary embryo is liable to be struck several times by other bodies of up to half its own diameter. Such an impact may have the ability to trigger core formation. Traditional accretion models have had great difficulty explaining the formation of the core. If one admits the importance of infrequent large events that may melt an entire hemisphere, the core formation difficulty vanishes. Millimeter-size iron blebs in the melted region will rain out due to their density difference with the silicate melt. Core formation may not require the melting of the entire hemisphere of the planet. The conditions are explored under which impact induced core formation may occur.

  12. SYNOVIAL GIANT CELL TUMOR OF THE KNEE

    PubMed Central

    Abdalla, Rene Jorge; Cohen, Moisés; Nóbrega, Jezimar; Forgas, Andrea

    2015-01-01

    Synovial giant cell tumor is a benign neoplasm, rarely reported in the form of malignant metastasis. Synovial giant cell tumor most frequently occurs on the hand, and, most uncommon, on the ankle and knee. In the present study, the authors describe a rare case of synovial giant cell tumor on the knee as well as the treatment approach. Arthroscopy has been shown, in this case, to be the optimal method for treating this kind of lesion, once it allowed a less aggressive approach, while providing good visualization of all compartments of knee joint and full tumor resection. PMID:27004193

  13. Rotation and macroturbulence in bright giants

    SciTech Connect

    Gray, D.F.; Toner, C.G.

    1986-11-01

    Spectral line profiles of 35 F, G, and K bright giants were analyzed to obtain rotation rates, v sin i, and macroturbulence dispersion. This sample indicates that rotation rates of cool class II giants is less than 11 km/s, in contrast with some recent periodicity measurements. Macroturbulence dispersion generally increases with effective temperature, but the range of values at a given effective temperature is much larger than seen for lower luminosity classes; this is interpreted in terms of red-giant and blue-loop evolution. No evidence is found for angular momentum dissipation on the first crossing of the H-R diagram. 57 references.

  14. The Metallicity of Giant Planets

    NASA Astrophysics Data System (ADS)

    Thorngren, Daniel P.; Fortney, Jonathan

    2015-12-01

    Unique clues about the formation processes of giant planets can be found in their bulk compositions. Transiting planets provide us with bulk density determinations that can then be compared to models of planetary structure and evolution, to deduce planet bulk metallicities. At a given mass, denser planets have a higher mass fraction of metals. However, the unknown hot Jupiter "radius inflation" mechanism leads to under-dense planets that severely biases this work. Here we look at cooler transiting gas giants (Teff < 1000 K), which do not exhibit the radius inflation effect seen in their warmer cousins. We identified 40 such planets between 20 M_Earth and 20 M_Jup from the literature and used evolution models to determine their bulk heavy-element ("metal") mass. Several important trends are apparent. We see that all planets have at least ~10 M_Earth of metals, and that the mass of metal correlates strongly with the total mass of the planet. The heavy-element mass goes as the square root of the total mass. Both findings are consistent with the core accretion model. We also examined the effect of the parent star metallicity [Fe/H], finding that planets around high-metallicity stars are more likely to have large amounts of metal, but the relation appears weaker than previous studies with smaller sample sizes had suggested. We also looked for connections between bulk composition and planetary orbital parameters and stellar parameters, but saw no pattern, which is also an important result. This work can be directly compared to current and future outputs from planet formation models, including population synthesis.

  15. Hydrodynamic Simulations of Giant Impacts

    NASA Astrophysics Data System (ADS)

    Reinhardt, Christian; Stadel, Joachim

    2013-07-01

    We studied the basic numerical aspects of giant impacts using Smoothed Particles Hydrodynamics (SPH), which has been used in most of the prior studies conducted in this area (e.g., Benz, Canup). Our main goal was to modify the massive parallel, multi-stepping code GASOLINE widely used in cosmological simulations so that it can properly simulate the behavior of condensed materials such as granite or iron using the Tillotson equation of state. GASOLINE has been used to simulate hundreds of millions of particles for ideal gas physics so that using several millions of particles in condensed material simulations seems possible. In order to focus our attention of the numerical aspects of the problem we neglected the internal structure of the protoplanets and modelled them as homogenous (isothermal) granite spheres. For the energy balance we only considered PdV work and shock heating of the material during the impact (neglected cooling of the material). Starting at a low resolution of 2048 particles for the target and the impactor we run several simulations for different impact parameters and impact velocities and successfully reproduced the main features of the pioneering work of Benz from 1986. The impact sends a shock wave through both bodies heating the target and disrupting the remaining impactor. As in prior simulations material is ejected from the collision. How much, and whether it leaves the system or survives in an orbit for a longer time, depends on the initial conditions but also on resolution. Increasing the resolution (to 1.2x10⁶ particles) results in both a much clearer shock wave and deformation of the bodies during the impact and a more compact and detailed "arm" like structure of the ejected material. Currently we are investigating some numerical issues we encountered and are implementing differentiated models, making one step closer to more realistic protoplanets in such giant impact simulations.

  16. Internal Rotation of the Red-giant Star KIC 4448777 by Means of Asteroseismic Inversion

    NASA Astrophysics Data System (ADS)

    Di Mauro, M. P.; Ventura, R.; Cardini, D.; Stello, D.; Christensen-Dalsgaard, J.; Dziembowski, W. A.; Paternò, L.; Beck, P. G.; Bloemen, S.; Davies, G. R.; De Smedt, K.; Elsworth, Y.; García, R. A.; Hekker, S.; Mosser, B.; Tkachenko, A.

    2016-01-01

    We study the dynamics of the stellar interior of the early red-giant star KIC 4448777 by asteroseismic inversion of 14 splittings of the dipole mixed modes obtained from Kepler observations. In order to overcome the complexity of the oscillation pattern typical of red-giant stars, we present a procedure to extract the rotational splittings from the power spectrum. We find not only that the core rotates from a minimum of 8 to a maximum of 17 times faster than the surface, confirming previous inversion results generated for other red giants (Deheuvels et al.), but we also estimate the variation of the angular velocity within the helium core with a spatial resolution of 0.001R and verify the hypothesis of a sharp discontinuity in the inner stellar rotation. The results show that the entire core rotates rigidly and provide evidence for an angular velocity gradient around the base of the hydrogen-burning shell; however, we do not succeed in characterizing the rotational slope, due to the intrinsic limits of the applied techniques. The angular velocity, from the edge of the core, appears to decrease with increasing distance from the center, reaching an average value in the convective envelope of 68 ± 22 nHz. We conclude that a set of data that includes only dipolar modes is sufficient to infer quite accurately the rotation of a red giant not only in the dense core but also, with a lower level of confidence, in part of the radiative region and in the convective envelope.

  17. Studies on the ingestion characteristics of giant freshwater prawn, Chinese prawn and giant tiger prawn

    NASA Astrophysics Data System (ADS)

    Zang, Wei-Ling; Wang, Wei-Dong; Dai, Xi-Lin; Jiang, Min; Zhu, Zheng-Guo; Yang, Ming-Hui; Liu, Xian-Zhong; Xu, Gui-Rong; Ding, Fu-Jiang

    2000-12-01

    The ingestion of giant freshwater prawn, Chinese prawn and giant tiger prawn had continuity and the ingestion high peak occurred at night. Light and temperature had significant effects on the daily ingestion rate (DIR) of giant freshwater prawn Macrobrachium rosenbergii. Red light and blue light favorably induced favorable ingestion. In the adaptive range of temperature, the DIR increased with rising temperature and feeding frequency, but decreased with rising body weight.

  18. Nonexistence of the self-accelerating dipole and related questions

    NASA Astrophysics Data System (ADS)

    Steane, Andrew M.

    2014-06-01

    We calculate the self-force of a constantly accelerating electric dipole, showing, in particular, that classical electromagnetism does not predict that an electric dipole could self-accelerate, nor could it levitate in a gravitational field. We also resolve a paradox concerning the inertial mass of a longitudinally accelerating dipole, showing that the combined system of dipole plus field can be assigned a well-defined energy-momentum four-vector, so that the principle of relativity is satisfied. We then present some general features of electromagnetic phenomena in a reference frame described by the Rindler metric, showing in particular that an observer fixed in a gravitational field described everywhere by the Rindler metric will find any charged object supported in the gravitational field to possess an electromagnetic self-force equal to that observed by an inertial observer relative to which the body undergoes rigid hyperbolic motion. It follows that the principle of equivalence is satisfied by these systems.

  19. Quantitative analysis on electric dipole energy in Rashba band splitting

    NASA Astrophysics Data System (ADS)

    Hong, Jisook; Rhim, Jun-Won; Kim, Changyoung; Ryong Park, Seung; Hoon Shim, Ji

    2015-09-01

    We report on quantitative comparison between the electric dipole energy and the Rashba band splitting in model systems of Bi and Sb triangular monolayers under a perpendicular electric field. We used both first-principles and tight binding calculations on p-orbitals with spin-orbit coupling. First-principles calculation shows Rashba band splitting in both systems. It also shows asymmetric charge distributions in the Rashba split bands which are induced by the orbital angular momentum. We calculated the electric dipole energies from coupling of the asymmetric charge distribution and external electric field, and compared it to the Rashba splitting. Remarkably, the total split energy is found to come mostly from the difference in the electric dipole energy for both Bi and Sb systems. A perturbative approach for long wave length limit starting from tight binding calculation also supports that the Rashba band splitting originates mostly from the electric dipole energy difference in the strong atomic spin-orbit coupling regime.

  20. Warped AdS3/dipole-CFT duality

    NASA Astrophysics Data System (ADS)

    Song, Wei; Strominger, Andrew

    2012-05-01

    String theory contains solutions with {{SL}}( {{2},{R}} ){{R}} × {{U}}{( {1} )_L} -invariant warped AdS3 (WAdS3) factors arising as continuous deformations of ordinary AdS3 factors. We propose that some of these are holographically dual to the IR limits of nonlocal dipole-deformed 2D D-brane gauge theories, referred to as "dipole CFTs". Neither the bulk nor boundary theories are currently well-understood, and consequences of the proposed duality for both sides is investigated. The bulk entropy-area law suggests that dipole CFTs have (at large N) a high-energy density of states which does not depend on the deformation parameter. Putting the boundary theory on a spatial circle leads to closed timelike curves in the bulk, suggesting a relation of the latter to dipole-type nonlocality.

  1. Development of Cellular Magnetic Dipoles in Magnetotactic Bacteria

    PubMed Central

    Faivre, Damien; Fischer, Anna; Garcia-Rubio, Inés; Mastrogiacomo, Giovanni; Gehring, Andreas U.

    2010-01-01

    Magnetotactic bacteria benefit from their ability to form cellular magnetic dipoles by assembling stable single-domain ferromagnetic particles in chains as a means to navigate along Earth's magnetic field lines on their way to favorable habitats. We studied the assembly of nanosized membrane-encapsulated magnetite particles (magnetosomes) by ferromagnetic resonance spectroscopy using Magnetospirillum gryphiswaldense cultured in a time-resolved experimental setting. The spectroscopic data show that 1), magnetic particle growth is not synchronized; 2), the increase in particle numbers is insufficient to build up cellular magnetic dipoles; and 3), dipoles of assembled magnetosome blocks occur when the first magnetite particles reach a stable single-domain state. These stable single-domain particles can act as magnetic docks to stabilize the remaining and/or newly nucleated superparamagnetic particles in their adjacencies. We postulate that docking is a key mechanism for building the functional cellular magnetic dipole, which in turn is required for magnetotaxis in bacteria. PMID:20713012

  2. WHT, DIPOL-2 polarimetry of Nova Sgr 2015b

    NASA Astrophysics Data System (ADS)

    Harvey, Eamonn; Berdyugin, Andrei; Redman, Matt

    2015-09-01

    We report polarimetry data from three nights observing of Nova Sgr 2015b (also PNV J18365700-2855420 or V5668 Sgr) with the William Herschel Telescope in the BVR passbands using the DIPOL-2 instrument.

  3. Initial tests of an AC dipole for the Tevatron

    SciTech Connect

    Miyamoto, R.; Jansson, A.; Kopp, S.; Syphers, M.; /Fermilab

    2006-06-01

    The AC dipole is a device to diagnose transverse motions of a beam. It can achieve large-amplitude oscillations without two inevitable problems of conventional kicker/pinger magnets: decoherence and emittance growth. While not the first synchrotron to operate with an AC dipole, the Tevatron can now make use of its recently upgraded BPM system, providing unprecedented resolution for use with an AC dipole, to measure both linear and nonlinear properties of the accelerator. Plans are to provide AC dipole systems for both transverse degrees of freedom. Preliminary tests have been done using an audio power amplifier with an existing vertical pinger magnet, producing oscillation amplitudes up to 2{sigma} at 150 GeV. In this paper, we will present the configuration of this system. We also show the analysis of a first few data sets, including the direct measurement of beta functions at BPM locations.

  4. Dipole Theory of Heat Production and Absorption in Nerve Axon

    PubMed Central

    Wei, Ling Y.

    1972-01-01

    Exact formulas are derived for the energy change of a dipole system with two energy states (or bands) in a changing field in two cases: (a) no dipole flip-flop and (b) dipole flip-flop caused by stimulation. Based on these formulas, the positive and negative heats are calculated. The results are in good agreement with experiment in case b but are 60-180% larger in case a. Furthermore, the theory shows that the negative heat cannot be less than the positive heat in case a but can be either way in case b, the latter result being found prevalent in experiment. It is concluded that nerve excitation is most likely to involve dipole flip-flop at the membrane surface. The theory is consistent in the interpretations and correlations of the electrical, optical, and thermal effects observed in nerve axon. PMID:5056960

  5. Gyre-driven decay of the Earth's magnetic dipole.

    PubMed

    Finlay, Christopher C; Aubert, Julien; Gillet, Nicolas

    2016-01-01

    Direct observations indicate that the magnitude of the Earth's magnetic axial dipole has decreased over the past 175 years; it is now 9% weaker than it was in 1840. Here we show how the rate of dipole decay may be controlled by a planetary-scale gyre in the liquid metal outer core. The gyre's meridional limbs on average transport normal polarity magnetic flux equatorward and reverse polarity flux poleward. Asymmetry in the geomagnetic field, due to the South Atlantic Anomaly, is essential to the proposed mechanism. We find that meridional flux advection accounts for the majority of the dipole decay since 1840, especially during times of rapid decline, with magnetic diffusion making an almost steady contribution generally of smaller magnitude. Based on the morphology of the present field, and the persistent nature of the gyre, the current episode of dipole decay looks set to continue, at least for the next few decades. PMID:26814368

  6. Fourier-positivity constraints on QCD dipole models

    NASA Astrophysics Data System (ADS)

    Giraud, Bertrand G.; Peschanski, Robi

    2016-09-01

    Fourier-positivity (F-positivity), i.e. the mathematical property that a function has a positive Fourier transform, can be used as a constraint on the parametrization of QCD dipole-target cross-sections or Wilson line correlators in transverse position space r. They are Bessel transforms of positive transverse momentum dependent gluon distributions. Using mathematical F-positivity constraints on the limit r → 0 behavior of the dipole amplitudes, we identify the common origin of the violation of F-positivity for various, however phenomenologically convenient, dipole models. It is due to the behavior r 2 + ɛ, ɛ > 0 softer, even slightly, than color transparency. F-positivity seems thus to conflict with the present dipole formalism when it includes a QCD running coupling constant α (r).

  7. Optimized tapered dipole nanoantenna as efficient energy harvester.

    PubMed

    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. PMID:27410898

  8. Gyre-driven decay of the Earth's magnetic dipole

    NASA Astrophysics Data System (ADS)

    Finlay, Christopher C.; Aubert, Julien; Gillet, Nicolas

    2016-01-01

    Direct observations indicate that the magnitude of the Earth's magnetic axial dipole has decreased over the past 175 years; it is now 9% weaker than it was in 1840. Here we show how the rate of dipole decay may be controlled by a planetary-scale gyre in the liquid metal outer core. The gyre's meridional limbs on average transport normal polarity magnetic flux equatorward and reverse polarity flux poleward. Asymmetry in the geomagnetic field, due to the South Atlantic Anomaly, is essential to the proposed mechanism. We find that meridional flux advection accounts for the majority of the dipole decay since 1840, especially during times of rapid decline, with magnetic diffusion making an almost steady contribution generally of smaller magnitude. Based on the morphology of the present field, and the persistent nature of the gyre, the current episode of dipole decay looks set to continue, at least for the next few decades.

  9. Gyre-driven decay of the Earth's magnetic dipole

    PubMed Central

    Finlay, Christopher C.; Aubert, Julien; Gillet, Nicolas

    2016-01-01

    Direct observations indicate that the magnitude of the Earth's magnetic axial dipole has decreased over the past 175 years; it is now 9% weaker than it was in 1840. Here we show how the rate of dipole decay may be controlled by a planetary-scale gyre in the liquid metal outer core. The gyre's meridional limbs on average transport normal polarity magnetic flux equatorward and reverse polarity flux poleward. Asymmetry in the geomagnetic field, due to the South Atlantic Anomaly, is essential to the proposed mechanism. We find that meridional flux advection accounts for the majority of the dipole decay since 1840, especially during times of rapid decline, with magnetic diffusion making an almost steady contribution generally of smaller magnitude. Based on the morphology of the present field, and the persistent nature of the gyre, the current episode of dipole decay looks set to continue, at least for the next few decades. PMID:26814368

  10. SKEW QUADRUPOLES IN RHIC DIPOLE MAGNETS AT HIGH FIELDS.

    SciTech Connect

    JAIN, A.; GUPTA, P.; THOMPSON, P.; WANDERER, P.

    1995-06-11

    In the RHIC arc dipoles, the center of the cold mass lies above the center of the cryostat. At the maximum design field, the magnetic flux lines leak through the yoke to the asymmetrically located cryostat, which provides an additional return path. This introduces a systematic top-bottom asymmetry leading to a skew quadrupole term at high fields. A similar asymmetry is also created by any difference in weights of the upper and the lower yoke halves. Data from measurements of several RHIC dipoles are presented to study this effect. In the current production series of the RDIC dipoles, an attempt is made to compensate the effect of the cryostat by an asymmetry in the iron yoke. Seven dipoles with this type of yoke have been cold tested, and show a reduced saturation in the skew quadrupole term, as expected.

  11. Skew quadrupole in RHIC dipole magnets at high fields

    SciTech Connect

    Jain, A.; Gupta, P.; Thompson, P.; Wanderer, P.

    1995-07-01

    In the RHIC arc dipoles, the center of the cold mass lies above the center of the cryostat. At the maximum design field, the magnetic flux lines leak through the yoke to the asymmetrically located cryostat, which provides an additional return path. This introduces a systematic top-bottom asymmetry leading to a skew quadrupole term at high fields. A similar asymmetry is also created by any difference in weights of the upper and the lower yoke halves. Data from measurements of several RHIC dipoles are presented to study this effect. In the current production series of the RHIC dipoles, an attempt is made to compensate the effect of the cryostat by an asymmetry in the iron yoke. Seven dipoles with this type of yoke have been cold tested, and show a reduced saturation in the skew quadrupole term, as expected.

  12. Pygmy dipole resonance in 140Ce via inelastic scattering of 17O

    NASA Astrophysics Data System (ADS)

    Krzysiek, M.; Kmiecik, M.; Maj, A.; Bednarczyk, P.; Bracco, A.; Crespi, F. C. L.; Lanza, E. G.; Litvinova, E.; Paar, N.; Avigo, R.; Bazzacco, D.; Benzoni, G.; Birkenbach, B.; Blasi, N.; Bottoni, S.; Brambilla, S.; Camera, F.; Ceruti, S.; Ciemała, M.; de Angelis, G.; Désesquelles, P.; Eberth, J.; Farnea, E.; Gadea, A.; Giaz, A.; Görgen, A.; Gottardo, A.; Grebosz, J.; Hess, H.; Isocarte, R.; Jungclaus, A.; Leoni, S.; Ljungvall, J.; Lunardi, S.; Mazurek, K.; Menegazzo, R.; Mengoni, D.; Michelagnoli, C.; Milion, B.; Morales, A. I.; Napoli, D. R.; Nicolini, R.; Pellegri, L.; Pullia, A.; Quintana, B.; Recchia, F.; Reiter, P.; Rosso, D.; Salsac, M. D.; Siebeck, B.; Siem, S.; Söderström, P.-A.; Ur, C.; Valiente-Dobon, J. J.; Wieland, O.; Ziebliński, M.

    2016-04-01

    The γ decay from the high-lying states of 140Ce excited via inelastic scattering of 17O at a bombarding energy of 340 MeV was measured using the high-resolution AGATA-demonstrator array in coincidence with scattered ions detected in two segmented Δ E -E silicon detectors. Angular distributions of scattered ions and emitted γ rays were measured, as well as their differential cross sections. The excitation of 1- states below the neutron separation energy is similar to the one obtained in reactions with the α isoscalar probe. The comparison between the experimental differential cross sections and the corresponding predictions using the distorted-wave Born approximation allowed us to extract the isoscalar component of identified 1- pygmy states. For this analysis the form factor obtained by folding microscopically calculated transition densities and optical potentials was used.

  13. An analysis of Log Periodic Antenna with Printed Dipoles

    NASA Astrophysics Data System (ADS)

    Paul, A.; Gupta, I.

    1981-02-01

    An analysis of Log Periodic Antenna with Printed Dipoles is presented here. In this analysis, the wave equation for Hertz potential is solved in Cartesian coordinates applying the boundary conditions of a flat strip dipole. Using this model, the input currents to the antenna elements, the current distribution of the antenna elements, and the radiation pattern are computed. The computed results are compared with experimental results.

  14. Simulation of Whistler Chorus in a Compressed Dipole Field

    NASA Astrophysics Data System (ADS)

    Wu, S.; Denton, R. E.; Hudson, M.

    2015-12-01

    Earth's dipole magnetic field is constantly compressed by the solar wind and the compression is enhanced during magnetic storm. We simulate whistler chorus in a compressed dipole field using a hybrid code. The hybrid code uses the particle-in-cell technique in generalized orthogonal coordinates. In the hybrid code, a small fraction of electrons are treated as particles with anisotropic temperature that leads to the whistler instability. Other electrons are treated as a cold fluid without mass. The density of the fluid electrons is large such that the plasma frequency exceeds the electron gyro frequency. Ions serve as a fixed background. We model the compressed dipole field by adding a constant magnetic field component to the dipole field. The direction of the compressed component is the same as that of the dipole field at the equator. This model of the compressed dipole field yields a magnetic field with off-equator minima and smaller inhomogeneity than the dipole field near the equator. The distribution of hot anisotropic electrons along the magnetic field is a function of adiabatic invariants that satisfies MHD force balance. In the compressed dipole field, the hot electron anisotropy, hot electron density and plasma beta in the direction parallel to the background magnetic field are the maximum at the minimum magnetic field. In our simulation, whistler chorus are generated at the minimum magnetic field with a peak frequency in agreement with the prediction by WHAMP, a local dispersion relation solver. The waves propagate in both directions along the magnetic field. Waves that propagate to higher magnetic latitude are damped at the boundary by the artificial resistive layers, while waves that propagate to lower latitude towards the equator continue to grow.

  15. Magnetic field in the plane of a physical dipole

    NASA Astrophysics Data System (ADS)

    Binder, P.-M.; Grace, Alyssa L.; Hui, Kaleonui J.; Loving, Rebekah K.

    2016-07-01

    We study the magnetic field in the plane of a circular current-carrying loop. We both solve Biot–Savart’s equation numerically and perform measurements with high spatial resolution. The results extend our quantitative understanding of a physical magnetic dipole by providing an accurate and complete picture of the field in this plane, which complements existing analytical expressions valid at very small and large radius, near the loop axis, and for point dipoles.

  16. Magnetostatic potential theory and the lunar magnetic dipole field

    NASA Technical Reports Server (NTRS)

    Goldstein, M. L.

    1975-01-01

    The lunar magnetic dipole moment is discussed. It is proposed that if a primordial core magnetic field existed, it would give rise to a present day nonzero external dipole magnetic field. This conclusion is based on the assumption that the lunar mantle is at least slightly ferromagnetic, and thus would maintain a permanent magnetization after the disappearance of the core magnetic field. Using a simple mathematical model of the moon, calculations are performed which support this hypothesis.

  17. Enhancing Eu(3+) magnetic dipole emission by resonant plasmonic nanostructures.

    PubMed

    Hussain, Rabia; Kruk, Sergey S; Bonner, Carl E; Noginov, Mikhail A; Staude, Isabelle; Kivshar, Yuri S; Noginova, Natalia; Neshev, Dragomir N

    2015-04-15

    We demonstrate the enhancement of magnetic dipole spontaneous emission from Eu3+ ions by an engineered plasmonic nanostructure that controls the electromagnetic environment of the emitter. Using an optical microscope setup, an enhancement in the intensity of the Eu3+ magnetic dipole emission was observed for emitters located in close vicinity to a gold nanohole array designed to support plasmonic resonances overlapping with the emission spectrum of the ions. PMID:25872041

  18. Measurements of ground motion and SSC dipole vibrations

    SciTech Connect

    Parkhomchuk, V.V.; Shiltsev, V.D.; Weaver, H.J.

    1993-06-01

    The results of seismic ground measurements at the Superconducting Super Collider (SSC) site and investigations of vibrational properties of superconducting dipoles for the SSC are presented. Spectral analysis of the data obtained in the large frequency band from 0.05 Hz to 2000 Hz is done. Resonant behavior and the dipole-to-ground transform ratio are investigated. The influence of measured vibrations on SSC operations is considered.

  19. Classification of Uxo by Principal Dipole Polarizability

    NASA Astrophysics Data System (ADS)

    Kappler, K. N.

    2010-12-01

    Data acquired by multiple-Transmitter, multiple-receiver time-domain electromagnetic devices show great potential for determining the geometric and compositional information relating to near surface conductive targets. Here is presented an analysis of data from one such system; the Berkeley Unexploded-ordnance Discriminator (BUD) system. BUD data are succinctly reduced by processing the multi-static data matrices to obtain magnetic dipole polarizability matrices for data from each time gate. When viewed over all time gates, the projections of the data onto the principal polar axes yield so-called polarizability curves. These curves are especially well suited to discriminating between subsurface conductivity anomalies which correspond to objects of rotational symmetry and irregularly shaped objects. The curves have previously been successfully employed as library elements in a pattern recognition scheme aimed at discriminating harmless scrap metal from dangerous intact unexploded ordnance. However, previous polarizability-curve matching methods have only been applied at field sites which are known a priori to be contaminated by a single type of ordnance, and furthermore, the particular ordnance present in the subsurface was known to be large. Thus signal amplitude was a key element in the discrimination process. The work presented here applies feature-based pattern classification techniques to BUD field data where more than 20 categories of object are present. Data soundings from a calibration grid at the Yuma, AZ proving ground are used in a cross validation study to calibrate the pattern recognition method. The resultant method is then applied to a Blind Test Grid. Results indicate that when lone UXO are present and SNR is reasonably high, Polarizability Curve Matching successfully discriminates UXO from scrap metal when a broad range of objects are present.

  20. Modeling Barkhausen Noise in magnetic glasses with dipole-dipole interactions

    NASA Astrophysics Data System (ADS)

    Dubey, Awadhesh K.; Hentschel, H. George E.; Jaiswal, Prabhat K.; Mondal, Chandana; Procaccia, Itamar; Gupta, Bhaskar Sen

    2015-10-01

    Long-ranged dipole-dipole interactions in magnetic glasses give rise to magnetic domains having labyrinthine patterns on the scale of about 1 micron. Barkhausen Noise then results from the movement of domain boundaries which is modeled by the motion of elastic membranes with random pinning. Here we propose that on the nanoscale new sources of Barkhausen Noise can arise. We propose an atomistic model of magnetic glasses in which we measure the Barkhausen Noise which results from the creation of new domains and the movement of domain boundaries on the nanoscale. The statistics of the Barkhausen Noise found in our simulations is in striking disagreement with the expectations in the literature. In fact we find exponential statistics without any power law, stressing the fact that Barkhausen Noise can belong to very different universality classes. In the present model the essence of the phenomenon is the fact that the spin response Green's function is decaying too rapidly for having sufficiently large magnetic jumps. A theory is offered in excellent agreement with the measured data without any free parameter.

  1. Constraints on Exotic Dipole-Dipole Couplings between Electrons at the Micrometer Scale.

    PubMed

    Kotler, Shlomi; Ozeri, Roee; Kimball, Derek F Jackson

    2015-08-21

    New constraints on exotic dipole-dipole interactions between electrons at the micrometer scale are established, based on a recent measurement of the magnetic interaction between two trapped 88Sr(+) ions. For light bosons (mass≤0.1  eV) we obtain a 90% confidence interval for an axial-vector-mediated interaction strength of |g(A)(e)g(A)(e)/4πℏc|≤1.2×10(-17). Assuming CPT invariance, this constraint is compared to that on anomalous electron-positron interactions, derived from positronium hyperfine spectroscopy. We find that the electron-electron constraint is 6 orders of magnitude more stringent than the electron-positron counterpart. Bounds on pseudoscalar-mediated interaction as well as on torsion gravity are also derived and compared with previous work performed at different length scales. Our constraints benefit from the high controllability of the experimental system which contained only two trapped particles. It therefore suggests a useful new platform for exotic particle searches, complementing other experimental efforts. PMID:26340180

  2. Many particle magnetic dipole-dipole and hydrodynamic interactions in magnetizable stent assisted magnetic drug targeting

    NASA Astrophysics Data System (ADS)

    Cregg, P. J.; Murphy, Kieran; Mardinoglu, Adil; Prina-Mello, Adriele

    2010-08-01

    The implant assisted magnetic targeted drug delivery system of Avilés, Ebner and Ritter is considered both experimentally ( in vitro) and theoretically. The results of a 2D mathematical model are compared with 3D experimental results for a magnetizable wire stent. In this experiment a ferromagnetic, coiled wire stent is implanted to aid collection of particles which consist of single domain magnetic nanoparticles (radius ≈10 nm). In order to model the agglomeration of particles known to occur in this system, the magnetic dipole-dipole and hydrodynamic interactions for multiple particles are included. Simulations based on this mathematical model were performed using open source C++ code. Different initial positions are considered and the system performance is assessed in terms of collection efficiency. The results of this model show closer agreement with the measured in vitro experimental results and with the literature. The implications in nanotechnology and nanomedicine are based on the prediction of the particle efficiency, in conjunction with the magnetizable stent, for targeted drug delivery.

  3. Quantum synchronization of ultracold atoms with dipole-dipole interactions in an optical lattice

    NASA Astrophysics Data System (ADS)

    Zhu, Bihui; Restrepo, Juan; Rey, Ana Maria; Holland, Murray

    2014-05-01

    Ultracold atoms confined in an optical lattice have been utilized as a powerful platform to study versatile many-body physics both experimentally and theoretically. A recent research focus has been the novel phenomena that would emerge with long-range interactions, which become especially important for atomic clocks where ultrahigh precision can amplify these effects. We develop theoretical models treating the two-level atoms as oscillators and study the synchronization of phases among a large ensemble of atoms coupled by dipole-dipole interactions, where the effect of geometry becomes relevant. We investigate the onset of synchronization and the related phase diagram, and further discuss the parameter regime for potential experimental observation using ultracold atoms such as Strontium. By applying different numerical methods, eg., quantum trajectories and truncated Wigner approximations to compare with the mean-field results, we also explore the underlying role of quantum fluctuations. We acknowledge funding from NIST, JILA-NSF-PFC-1125844, NSF-PIF, ARO, ARO-DARPA-OLE, and AFOSR.

  4. Constraints on Exotic Dipole-Dipole Couplings between Electrons at the Micrometer Scale

    NASA Astrophysics Data System (ADS)

    Kotler, Shlomi; Ozeri, Roee; Kimball, Derek F. Jackson

    2015-08-01

    New constraints on exotic dipole-dipole interactions between electrons at the micrometer scale are established, based on a recent measurement of the magnetic interaction between two trapped 88Sr+ ions. For light bosons (mass≤0.1 eV ) we obtain a 90% confidence interval for an axial-vector-mediated interaction strength of |gAegAe/4 π ℏc | ≤1.2 ×10-17 . Assuming C P T invariance, this constraint is compared to that on anomalous electron-positron interactions, derived from positronium hyperfine spectroscopy. We find that the electron-electron constraint is 6 orders of magnitude more stringent than the electron-positron counterpart. Bounds on pseudoscalar-mediated interaction as well as on torsion gravity are also derived and compared with previous work performed at different length scales. Our constraints benefit from the high controllability of the experimental system which contained only two trapped particles. It therefore suggests a useful new platform for exotic particle searches, complementing other experimental efforts.

  5. Magnetic dipole-dipole sensing at atomic scale using electron spin resonance STM

    NASA Astrophysics Data System (ADS)

    Choi, T.; Paul, W.; Rolf-Pissarczyk, S.; MacDonald, A.; Yang, K.; Natterer, F. D.; Lutz, C. P.; Heinrich, A. J.

    Magnetometry having both high magnetic field sensitivity and atomic resolution has been an important goal for applications in diverse fields covering physics, material science, and biomedical science. Recent development of electron spin resonance STM (ESR-STM) promises coherent manipulation of spins and studies on magnetic interaction of artificially built nanostructures, leading toward quantum computation, simulation, and sensors In ESR-STM experiments, we find that the ESR signal from an Fe atom underneath a STM tip splits into two different frequencies when we position an additional Fe atom nearby. We measure an ESR energy splitting that decays as 1/r3 (r is the separation of the two Fe atoms), indicating that the atoms are coupled through magnetic dipole-dipole interaction. This energy and distance relation enables us to determine magnetic moments of atoms and molecules on a surface with high precision in energy. Unique and advantageous aspects of ESR-STM are the atom manipulation capabilities, which allow us to build atomically precise nanostructures and examine their interactions. For instance, we construct a dice cinque arrangement of five Fe atoms, and probe their interaction and energy degeneracy. We demonstrate the ESR-STM technique can be utilized for quantum magnetic sensors.

  6. Application of the discrete dipole approximation to very large refractive indices: Filtered coupled dipoles revived.

    PubMed

    Yurkin, Maxim A; Min, Michiel; Hoekstra, Alfons G

    2010-09-01

    We compared three formulations of the discrete dipole approximation (DDA) for simulation of light scattering by particles with refractive indices m=10+10i , 0.1+i , and 1.6+0.01i . These formulations include the filtered coupled dipoles (FCD), the lattice dispersion relation (LDR) and the radiative reaction correction. We compared the number of iterations required for the convergence of the iterative solver (proportional to simulation time) and the accuracy of final results. We showed that the LDR performance for m=10+10i is especially bad, while the FCD is a good option for all cases studied. Moreover, we analyzed the detailed structure of DDA errors and the spectrum of the DDA interaction matrix to understand the performance of the FCD. In particular, this spectrum, obtained with the FCD for particles smaller than the wavelength, falls into the bounds, physically implied for the spectrum of the infinite-dimensional integral scattering operator, contrary to two other DDA formulations. Finally, such extreme refractive indices can now be routinely simulated using modern desktop computers using the publicly available ADDA code, which includes an efficient implementation of the FCD. PMID:21230209

  7. Interstrand dipole-dipole interactions can stabilize the collagen triple helix.

    PubMed

    Shoulders, Matthew D; Raines, Ronald T

    2011-07-01

    The amino acid sequence of collagen is composed of GlyXaaYaa repeats. A prevailing paradigm maintains that stable collagen triple helices form when (2S)-proline (Pro) or Pro derivatives that prefer the C(γ)-endo ring pucker are in the Xaa position and Pro derivatives that prefer the C(γ)-exo ring pucker are in the Yaa position. Anomalously, an amino acid sequence in an invertebrate collagen has (2S,4R)-4-hydroxyproline (Hyp), a C(γ)-exo-puckered Pro derivative, in the Xaa position. In certain contexts, triple helices with Hyp in the Xaa position are now known to be hyperstable. Most intriguingly, the sequence (GlyHypHyp)(n) forms a more stable triple helix than does the sequence (GlyProHyp)(n). Competing theories exist for the physicochemical basis of the hyperstability of (GlyHypHyp)(n) triple helices. By synthesizing and analyzing triple helices with different C(γ)-exo-puckered proline derivatives in the Xaa and Yaa positions, we conclude that interstrand dipole-dipole interactions are the primary determinant of their additional stability. These findings provide a new framework for understanding collagen stability. PMID:21482820

  8. Space Propulsion Based on Dipole Assisted IEC System

    SciTech Connect

    Miley, George H.; Thomas, Robert; Takeyama, Yoshikazu; Momota, Hiromu; Shrestha, Prajakti J.

    2006-01-20

    A potential opportunity to enhance Inertial Electrostatic Confinement (IEC) fusion propulsion exists by introducing a magnetic dipole into the IEC chamber. The dipole fields should increase the plasma density, hence fusion rate, in the center region of the IEC and the combined IEC and dipole confinement properties will reduce plasma losses. To demonstrate that a hybrid Dipole-IEC (DaIEC) configuration can provide improved confinement vs. a stand alone IEC, a first model DaIEC experiment has been benchmarked against a reference IEC. A triple Langmuir probe was used to measure the electron temperature and density. It was confirmed that the magnetic field increases the electron density by an order of magnitude and the addition of a controlled electrical potential to the dipole structure allows control of space charge buildup in the dense core region. This paper describes the dipole assisted IEC concept, its advantages, and soon missions it is well suited for. Here the present status of DaIEC experiments are described, the issues for scale up are discussed, and a conceptual plan for a power unit development is presented.

  9. Innate predator recognition in giant pandas.

    PubMed

    Du, Yiping; Huang, Yan; Zhang, Hemin; Li, Desheng; Yang, Bo; Wei, Ming; Zhou, Yingmin; Liu, Yang

    2012-02-01

    Innate predator recognition confers a survival advantage to prey animals. We investigate whether giant pandas exhibit innate predator recognition. We analyzed behavioral responses of 56 naive adult captive giant pandas (Ailuropoda melanoleuca), to urine from predators and non-predators and water control. Giant pandas performed more chemosensory investigation and displayed flehmen behaviors more frequently in response to predator urine compared to both non-predator urine and water control. Subjects also displayed certain defensive behaviors, as indicated by vigilance, and in certain cases, fleeing behaviors. Our results suggest that there is an innate component to predator recognition in captive giant pandas, although such recognition was only slight to moderate. These results have implications that may be applicable to the conservation and reintroduction of this endangered species. PMID:22303845

  10. Mass loss in red giants and supergiants

    NASA Technical Reports Server (NTRS)

    Sanner, F.

    1975-01-01

    The circumstellar envelopes surrounding late-type giants and supergiants were studied using high resolution, photoelectric scans of strong optical resonance lines. A method for extracting the circumstellar from the stellar components of the lines allowed a quantitative determination of the physical conditions in the envelopes and the rates of mass loss at various positions in the red giant region of the HR diagram. The observed strengthening of the circumstellar spectrum with increasing luminosity and later spectral type is probably caused by an increase in the mass of the envelopes. The mass loss rate for individual stars is proportional to the visual luminosity; high rates for the supergiants suggest that mass loss is important in their evolution. The bulk of the mass return to the interstellar medium in the red giant region comes from the normal giants, at a rate comparable to that of planetary nebulae.

  11. Tests of the Giant Impact Hypothesis

    NASA Technical Reports Server (NTRS)

    Jones, J. H.

    1998-01-01

    The giant impact hypothesis has gained popularity as a means of explaining a volatile-depleted Moon that still has a chemical affinity to the Earth. As Taylor's Axiom decrees, the best models of lunar origin are testable, but this is difficult with the giant impact model. The energy associated with the impact would be sufficient to totally melt and partially vaporize the Earth. And this means that there should he no geological vestige of Barber times. Accordingly, it is important to devise tests that may be used to evaluate the giant impact hypothesis. Three such tests are discussed here. None of these is supportive of the giant impact model, but neither do they disprove it.

  12. "GIANT" Steps to Create Online Orientations

    ERIC Educational Resources Information Center

    Bacon, Pamela

    2005-01-01

    Online orientation is provided due to the flexibility of online learning. The online orientation consists of the GIANT steps which stands for Get support, Identify your curriculum, Assemble your program, Navigate students through the pilot project and Test students.

  13. Selecting M-giants with WISE photometry

    NASA Astrophysics Data System (ADS)

    Li, Jing

    2015-08-01

    We use M-giants, M-dwarfs and QSOs identified by LAMOST to assess how well WISE & 2MASS colour-cuts can separate these populations through photometry. We find that the WISE bands are very efficient to separate M-giants from M-dwarfs, especially for the early-type stars. We derive a new photometric relation to estimate [Fe/H] for M-giants. We show that previous photometric distance relations may be biased and devise a new empirical distance relation. We detect M-giants in the Sagittarius stream from the ALLWISE Source Archive. Our detection shows good agreement with the bright stream, although the leading tail appears to be misaligned by a couple of degrees. We have measured the metallicity distribution at four locations along the stream, finding a clear metallicity offset between the leading and trailing tails.

  14. EUVE Observations of the Hyades Giants

    NASA Technical Reports Server (NTRS)

    Stern, Robert A.; Oliversen, Ronald J. (Technical Monitor)

    1998-01-01

    We describe EUVE and ROSAT observations of the Hyades K0 III giants theta(sup 1) (vB 71 = HR1411) and gamma (vB 28 = HR1346) Tau. We also discuss ASCA observations of theta(sup 1)Tau. The coronal activity of these "clump" giants is intermediate between that of the Sun and of high activity stars such as RS CVn systems. There is no evidence for significant short or long term variability up to several years. Modeling of the individual and combined spectra suggest that these two X-ray and EUV-bright Hyades giants resemble in their activity levels another clump giant, beta Cet, with a peak in the emission measure distribution near log T approx. 6.8, reminiscent of the Capella emission measure "bump."

  15. Chromospheric activity of cool giant stars

    NASA Technical Reports Server (NTRS)

    Steiman-Cameron, T. Y.

    1986-01-01

    During the seventh year of IUE twenty-six spectra of seventeen cool giant stars ranging in spectral type from K3 thru M6 were obtained. Together with spectra of fifteen stars observed during the sixth year of IUE, these low-resolution spectra have been used to: (1) examine chromospheric activity in the program stars and late type giants in general, and (2) evaluate the extent to which nonradiative heating affects the upper levels of cool giant photospheres. The stars observed in this study all have well determined TiO band strengths, angular diameters (determined from lunar occulations), bolometric fluxes, and effective temperatures. Chromospheric activity can therefore be related to effective temperatures providing a clearer picture of activity among cool giant stars than previously available. The stars observed are listed.

  16. EUVE Observations of the Hyades Giants

    NASA Technical Reports Server (NTRS)

    Stern, Robert A.

    1998-01-01

    The contractor describes EUVE and ROSAT observations of the Hyades K0 III giants theta(sup 1(vB 71 = HR 1411) and gamma$ (vB 28 = HR 1346) Tau, and ASCA observations of theta(sup 1) Tau. The coronal activity of these "clump" giants is intermediate between that of the Sun and of high-activity stars such as RS CVn systems. There is no evidence for significant short or long term variability up to several years. Modeling of the individual and combined spectra suggest that these two X-ray and EUV- bright Hyades giants resemble in their activity levels another clump giant, beta Cet, with a peak in the emission measure distribution near log T approx. 6.8, reminiscent of the Capella emission measure "bump."

  17. Giant cell arteritis presenting as scalp necrosis.

    PubMed

    Maidana, Daniel E; Muñoz, Silvia; Acebes, Xènia; Llatjós, Roger; Jucglà, Anna; Alvarez, Alba

    2011-01-01

    The differential of scalp ulceration in older patients should include several causes, such as herpes zoster, irritant contact dermatitis, ulcerated skin tumors, postirradiation ulcers, microbial infections, pyoderma gangrenosum, and giant cell arteritis. Scalp necrosis associated with giant cell arteritis was first described in the 1940s. The presence of this dermatological sign within giant cell arteritis represents a severity marker of this disease, with a higher mean age at diagnosis, an elevated risk of vision loss and tongue gangrene, as well as overall higher mortality rates, in comparison to patients not presenting this manifestation. Even though scalp necrosis due to giant cell arteritis is exceptional, a high level of suspicion must be held for this clinical finding, in order to initiate prompt and proper treatment and avoid blindness. PMID:21789466

  18. Central giant cell granuloma of the maxilla

    PubMed Central

    Gupta, Manish; Gupta, Monica; Singh, Sunder; Kaur, Rupinder

    2013-01-01

    Central giant cell granuloma (CGCG), formerly called giant cell reparative granuloma, is a non-neoplastic proliferative lesion of an unknown aetiology. It occurs most commonly in the mandible. The case reported here resembled a wide variety of conditions that led to a misdiagnosis both on clinical and radiographic examinations but was histopathologically diagnosed as CGCG. We managed this case by endoscopic excision and curettage via nasal route without producing external scar and avoiding damage to the un-erupted tooth. PMID:23475995

  19. Arterial Embolization of Giant Hepatic Hemangiomas

    SciTech Connect

    Giavroglou, Constantinos; Economou, Hippolete; Ioannidis, Ioannis

    2003-02-15

    Hepatic cavernous hemangiomas are usually small and asymptomatic. They are usually discovered incidentally and only a few require treatment. However, giant hemangiomas may cause symptoms,which are indications for treatment. We describe four cases of symptomatic giant hepatic hemangiomas successfully treated with transcatheter arterial embolization, performed with polyvinyl alcohol particles. There were no complications. Follow-up with clinical and imaging examinations showed disappearance of symptoms and decrease in size of lesions.

  20. Management of giant liver hemangiomas: an update.

    PubMed

    Hoekstra, Lisette T; Bieze, Matthanja; Erdogan, Deha; Roelofs, Joris J T H; Beuers, Ulrich H W; van Gulik, Thomas M

    2013-03-01

    Liver hemangiomas are the most common benign liver tumors and are usually incidental findings. Liver hemangiomas are readily demonstrated by abdominal ultrasonography, computed tomography or magnetic resonance imaging. Giant liver hemangiomas are defined by a diameter larger than 5 cm. In patients with a giant liver hemangioma, observation is justified in the absence of symptoms. Surgical resection is indicated in patients with abdominal (mechanical) complaints or complications, or when diagnosis remains inconclusive. Enucleation is the preferred surgical method, according to existing literature and our own experience. Spontaneous or traumatic rupture of a giant hepatic hemangioma is rare, however, the mortality rate is high (36-39%). An uncommon complication of a giant hemangioma is disseminated intravascular coagulation (Kasabach-Merritt syndrome); intervention is then required. Herein, the authors provide a literature update of the current evidence concerning the management of giant hepatic hemangiomas. In addition, the authors assessed treatment strategies and outcomes in a series of patients with giant liver hemangiomas managed in our department. PMID:23445235