Electric dipoles on magnetic monopoles in spin ice.
Khomskii, D I
2012-01-01
The close connection of electricity and magnetism is one of the cornerstones of modern physics. This connection has a crucial role from a fundamental point of view and in practical applications, including spintronics and multiferroic materials. A breakthrough was a recent proposal that in magnetic materials called spin ice the elementary excitations have a magnetic charge and behave as magnetic monopoles. I show that, besides magnetic charge, there should be an electric dipole attached to each magnetic monopole. This opens new possibilities to study and control such monopoles using an electric field. Thus, the electric-magnetic analogy goes even further than usually assumed: whereas electrons have electric charge and magnetic dipole (spin), magnetic monopoles in spin ice, while having magnetic charge, also have an electric dipole. PMID:22713746
Duality and Electric Dipole Moment of Magnetic Monopole
NASA Astrophysics Data System (ADS)
Kobayashi, M.
After a few personal recollections on Professor Shoichi Sakata and thetheory group of Nagoya Univiersity, the electric dipole moment of magnetic monopoles is discussed. In the N = 2 supersymmetric gauge model, the explicit calculation shows that the fraction of the fermion contribution to the moment is given by a curious number.
Porsev, S. G.; Ginges, J. S. M.; Flambaum, V. V.
2011-04-15
We have considered a mechanism for inducing a time-reversal violating electric dipole moment (EDM) in atoms through the interaction of a nuclear EDM d{sub N} with the hyperfine interaction, the ''magnetic moment effect''. We have derived the operator for this interaction and presented analytical formulas for the matrix elements between atomic states. Induced EDMs in the diamagnetic atoms {sup 129}Xe, {sup 171}Yb, {sup 199}Hg, {sup 211}Rn, and {sup 225}Ra have been calculated numerically. From the experimental limits on the atomic EDMs of {sup 129}Xe and {sup 199}Hg we have placed the following constraints on the nuclear EDMs, |d{sub N}({sup 129}Xe)|<1.1x10{sup -21}|e|cm and |d{sub N}({sup 199}Hg)|<2.8x10{sup -24}|e|cm.
A colocated magnetic loop, electric dipole array antenna (preliminary results)
NASA Astrophysics Data System (ADS)
Overfelt, P. L.; Bowling, D. R.; White, D. J.
1994-09-01
We present a detailed electromagnetic analysis of an electrically small colocated electric dipole and magnetic loop antenna array. This antenna is the simplest example of the Grimes multipole class of antenna arrays. We have determined that since the interaction term between the two elements disappears from the radial complex power, we were able to set the radial reactance to zero by choosing appropriate current magnitudes and phases on the array elements. By driving the two elements in quadrature, we obtained a much increased radiation intensity and directivity as well as increased radiated power.
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.
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.
Controlling magnetic and electric dipole modes in hollow silicon nanocylinders.
van de Haar, Marie Anne; van de Groep, Jorik; Brenny, Benjamin J M; Polman, Albert
2016-02-01
We propose a dielectric nanoresonator geometry consisting of hollow dielectric nanocylinders which support geometrical resonances. We fabricate such hollow Si particles with an outer diameter of 108-251 nm on a Si substrate, and determine their resonant modes with cathodo-luminescence (CL) spectroscopy and optical dark-field (DF) scattering measurements. The scattering behavior is numerically investigated in a systematic fashion as a function of wavelength and particle geometry. We find that the additional design parameter as a result of the introduction of a center gap can be used to control the relative spectral spacing of the resonant modes, which will enable additional control over the angular radiation pattern of the scatterers. Furthermore, the gap offers direct access to the enhanced magnetic dipole modal field in the center of the particle. PMID:26906780
NASA Astrophysics Data System (ADS)
Dzuba, V. A.; Flambaum, V. V.
2016-05-01
Hyperfine-induced electric dipole contributions may significantly increase probabilities of otherwise very weak electric octupole and magnetic quadrupole atomic clock transitions (e.g., transitions between s and f electron orbitals). These transitions can be used for exceptionally accurate atomic clocks, quantum information processing, and the search for dark matter. They are very sensitive to new physics beyond the standard model, such as temporal variation of the fine-structure constant, the Lorentz invariance, and Einstein equivalence principle violation. We formulate conditions under which the hyperfine-induced electric dipole contribution dominates and perform calculations of the hyperfine structure and E3, M2 and the hyperfine-induced E1 transition rates for a large number of atoms and ions of experimental interest. Due to the hyperfine quenching the electric octupole clock transition in +173Yb is 2 orders of magnitude stronger than that in currently used +171Yb. Some enhancement is found in 13+143Nd, 14+149Pm, 14+147Sm, and 15+147Sm ions.
Modification of electric and magnetic dipole emission in anisotropic plasmonic systems
NASA Astrophysics Data System (ADS)
Noginova, N.; Hussain, R.; Noginov, M. A.; Vella, J.; Urbas, A.
Spontaneous emission of a dipole can be significantly modified in metamaterials, providing opportunities to engineer emission rates, yields, spectra, and angular patterns. To better understand specifics of such modifications for electric and magnetic emitters, we study luminescence of Eu3+ ions placed in a close vicinity of arrays of gold nanostrips. The luminescence is strongly polarized, with the preferable polarization parallel to the direction of strips. Polarization patterns and angular distributions of radiation depend on wavelength, and are different for electric and magnetic dipole transitions. The results are discussed in terms of different coupling of emitters with radiative and high-loss modes.
NASA Astrophysics Data System (ADS)
Mansuripur, Masud
2015-01-01
The classical theory of electrodynamics cannot explain the existence and structure of electric and magnetic dipoles, yet it incorporates such dipoles into its fundamental equations, simply by postulating their existence and properties, just as it postulates the existence and properties of electric charges and currents. Maxwell's macroscopic equations are mathematically exact and self-consistent differential equations that relate the electromagnetic (EM) field to its sources, namely, electric charge-density 𝜌𝜌free, electric current-density 𝑱𝑱free, polarization 𝑷𝑷, and magnetization 𝑴𝑴. At the level of Maxwell's macroscopic equations, there is no need for models of electric and magnetic dipoles. For example, whether a magnetic dipole is an Amperian current-loop or a Gilbertian pair of north and south magnetic monopoles has no effect on the solution of Maxwell's equations. Electromagnetic fields carry energy as well as linear and angular momenta, which they can exchange with material media—the seat of the sources of the EM field—thereby exerting force and torque on these media. In the Lorentz formulation of classical electrodynamics, the electric and magnetic fields, 𝑬𝑬 and 𝑩𝑩, exert forces and torques on electric charge and current distributions. An electric dipole is then modeled as a pair of electric charges on a stick (or spring), and a magnetic dipole is modeled as an Amperian current loop, so that the Lorentz force law can be applied to the corresponding (bound) charges and (bound) currents of these dipoles. In contrast, the Einstein-Laub formulation circumvents the need for specific models of the dipoles by simply providing a recipe for calculating the force- and torque-densities exerted by the 𝑬𝑬 and 𝑯𝑯 fields on charge, current, polarization and magnetization. The two formulations, while similar in many respects, have significant
NASA Technical Reports Server (NTRS)
Harker, K. J.
1975-01-01
The generation of ULF waves by ground-based magnetic and electric dipoles is studied with a simplified model consisting of three adjoining homogeneous regions representing the groud, the vacuum (free space) region, and the ionosphere. The system is assumed to be immersed in a homogeneous magnetic field with an arbitrary tilt angle. By the use of Fourier techniques and the method of stationary phase, analytic expressions are obtained for the field strength of the compressional Alfven waves in the ionosphere. Expressions are also obtained for the strength of the torsional Alfven wave in the ionosphere and the ULF magnetic field at ground level. Numerical results are obtained for the compressional Alfven-wave field strength in the ionosphere with a nonvertical geomagnetic field and for the ULF magnetic field at ground level for a vertical geomagnetic field.
Stark Interference of Electric and Magnetic Dipole Transitions in the A-X Band of OH.
Schewe, H Christian; Zhang, Dongdong; Meijer, Gerard; Field, Robert W; Sartakov, Boris G; Groenenboom, Gerrit C; van der Avoird, Ad; Vanhaecke, Nicolas
2016-04-15
An experimental method is demonstrated that allows determination of the ratio between the electric (E1) and magnetic (M1) transition dipole moments in the A-X band of OH, including their relative sign. Although the transition strengths differ by more than 3 orders of magnitude, the measured M1-to-E1 ratio agrees with the ratio of the ab initio calculated values to within 3%. The relative sign is found to be negative, also in agreement with theory. PMID:27127965
W radiative decays and the determination of magnetic dipole and electric quadrupole moments of the W
Samuel, M.A. ); Sinha, N.; Sinha, R.; Sundaresan, M.K. )
1991-10-01
The magnetic dipole moment of the {ital W} boson is given by {mu}={ital e}(1+{kappa}+{lambda})/2{ital M}{sub {ital W}} and its electric quadrupole moment is given by {ital Q}={minus}{ital e}({kappa}{minus}{lambda})/{ital M}{sub {ital W}}{sup 2}. A nonstandard magnetic dipole moment and a nonstandard electric quadrupole moment lead to different differential decay distributions in the radiative decays of {ital W}{sup {plus minus}}, {ital W}{sup {minus}}{r arrow}{ital e}{bar {nu}}{gamma} and {ital W}{sup {minus}}{r arrow}{ital d{bar u}}{gamma}. While hard photons are characteristic signatures of {kappa}{ne}1 there is no such explicit signal for {lambda}{ne}0. We present a technique for the determination of the values of {kappa} and {lambda} by measuring the total number of events in two regions of phase space. This experiment could be done at the CERN {ital e}{sup +}{ital e{minus}} collider LEP II, where a clean source of {ital W} bosons will be available.
Magnetic g_e-FACTORS and Electric Dipole Moments of Lanthanide Monoxides: PrO
NASA Astrophysics Data System (ADS)
Wang, Hailing; Steimle, Timothy C.; Linton, Colan
2009-06-01
The very complex optical spectra of the lanthanide monoxides are caused by the insensitivity of the electronic energies to the numerous possible arrangements of the Ln^{2+} electrons in the 4f and 6s orbitals. Disentangling the complex optical spectra may be aided by using simple Ligand Field Theory(LFT) to establish the global electronic structure for the low-lying electronic states. A comparison of experimentally determined permanent electric dipole moments, μ_{el}, and magnetic dipole moments, μ_{m}, is an effective means of sorting this myriad of states and assessing the quality of LFT and other electronic structure methodologies. Here we report on the determination of the permanent electric dipole moments, μ_{el}, and magnetic g{_e}-factors for the X_{2}(Ω = 4.5) and [18.1] (Ω = 5.5) states of PrO from the analysis of the optical Stark and Zeeman spectra. The g_{e}-factors are compared with those computed using wavefunctions predicted from ligand field theory. The μ_{el} value for the X_{2}(Ω = 4.5) state is compared to ab initio, and density functional predictions and with the experimental values of other lanthanide monoxides. A phenomenological fit of μ_{el} for the entire series of LnO is used to predict μ_{el} for the isovalent actinide monoxide series. Carette, P.,; Hocquet,A. J. Mol. Spectrosc. 131 301, 1988. Dolg, M.; Stoll, H. Theor. Chim. Acta. 75,369, 1989. Wu, Z.; Guan, W. Meng, J. Su, Z. J. Cluster Science 18 444, 2007.
Stone, N. J.
2015-09-15
The most recent tabulations of nuclear magnetic dipole and electric quadrupole moments have been prepared and published by the Nuclear Data Section of the IAEA, Vienna [N. J. Stone, Report No. INDC(NDS)-0650 (2013); Report No. INDC(NDS)-0658 (2014)]. The first of these is a table of recommended quadrupole moments for all isotopes in which all experimental results are made consistent with a limited number of adopted standards for each element; the second is a combined listing of all measurements of both moments. Both tables cover all isotopes and energy levels. In this paper, the considerations relevant to the preparation of both tables are described, together with observations as to the importance and (where appropriate) application of necessary corrections to achieve the “best” values. Some discussion of experimental methods is included with emphasis on their precision. The aim of the published quadrupole moment table is to provide a standard reference in which the value given for each moment is the best available and for which full provenance is given. A table of recommended magnetic dipole moments is in preparation, with the same objective in view.
Selective Plasmonic Enhancement of Electric- and Magnetic-Dipole Radiations of Er Ions.
Choi, Bongseok; Iwanaga, Masanobu; Sugimoto, Yoshimasa; Sakoda, Kazuaki; Miyazaki, Hideki T
2016-08-10
Lanthanoid series are unique in atomic elements. One reason is because they have 4f electronic states forbidding electric-dipole (ED) transitions in vacuum and another reason is because they are very useful in current-day optical technologies such as lasers and fiber-based telecommunications. Trivalent Er ions are well-known as a key atomic element supporting 1.5 μm band optical technologies and also as complex photoluminescence (PL) band deeply mixing ED and magnetic-dipole (MD) transitions. Here we show large and selective enhancement of ED and MD radiations up to 83- and 26-fold for a reference bulk state, respectively, in experiments employing plasmonic nanocavity arrays. We achieved the marked PL enhancement by use of an optimal design for electromagnetic (EM) local density of states (LDOS) and by Er-ion doping in deep subwavelength precision. We moreover clarify the quantitative contribution of ED and MD radiations to the PL band, and the magnetic Purcell effect in the PL-decay temporal measurement. This study experimentally demonstrates a new scheme of EM-LDOS engineering in plasmon-enhanced photonics, which will be a key technique to develop loss-compensated and active plasmonic devices. PMID:27436631
NASA Astrophysics Data System (ADS)
Afach, S.; Baker, C. A.; Ban, G.; Bison, G.; Bodek, K.; Chowdhuri, Z.; Daum, M.; Fertl, M.; Franke, B.; Geltenbort, P.; Green, K.; van der Grinten, M. G. D.; Grujic, Z.; Harris, P. G.; Heil, W.; Hélaine, V.; Henneck, R.; Horras, M.; Iaydjiev, P.; Ivanov, S. N.; Kasprzak, M.; Kermaïdic, Y.; Kirch, K.; Knowles, P.; Koch, H.-C.; Komposch, S.; Kozela, A.; Krempel, J.; Lauss, B.; Lefort, T.; Lemière, Y.; Mtchedlishvili, A.; Naviliat-Cuncic, O.; Pendlebury, J. M.; Piegsa, F. M.; Pignol, G.; Prashant, P. N.; Quéméner, G.; Rebreyend, D.; Ries, D.; Roccia, S.; Schmidt-Wellenburg, P.; Severijns, N.; Weis, A.; Wursten, E.; Wyszynski, G.; Zejma, J.; Zenner, J.; Zsigmond, G.
2015-10-01
We report on the measurement of a Larmor frequency shift proportional to the electric-field strength for 199Hg atoms contained in a volume permeated with aligned magnetic and electric fields. This shift arises from the interplay between the inevitable magnetic field gradients and the motional magnetic field. The proportionality to electric-field strength makes it apparently similar to an electric dipole moment (EDM) signal, although unlike an EDM this effect is P- and T-conserving. We have used a neutron magnetic resonance EDM spectrometer, featuring a mercury co-magnetometer and an array of external cesium magnetometers, to measure the shift as a function of the applied magnetic field gradient. Our results are in good agreement with theoretical expectations.
Lithium electric dipole polarizability
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.
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…
Magnetic dipole transitions in the hydrogen molecule
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.
Axion induced oscillating electric dipole moments
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 m_{a} and strength ~ 10^{-32} e-cm, within four orders of magnitude of the present standard model DC limit, and two orders of magnitude above the nucleon, assuming standard axion model and dark matter parameters. This may suggest sensitive new experimental venues for the axion dark matter search.
Afach, S.; Fertl, M.; Franke, B. E-mail: bernhard.lauss@psi.ch; Kirch, K.; Bison, G.; Burri, F.; Chowdhuri, Z.; Daum, M.; Henneck, R.; Lauss, B. E-mail: bernhard.lauss@psi.ch; Meier, M.; Schmidt-Wellenburg, P.; Zsigmond, G.; Bodek, K.; Zejma, J.; Grujic, Z.; Kasprzak, M.; Weis, A.; Hélaine, V.; Koch, H.-C.; and others
2014-08-28
The Surrounding Field Compensation (SFC) system described in this work is installed around the four-layer Mu-metal magnetic shield of the neutron electric dipole moment spectrometer located at the Paul Scherrer Institute. The SFC system reduces the DC component of the external magnetic field by a factor of about 20. Within a control volume of approximately 2.5 m × 2.5 m × 3 m, disturbances of the magnetic field are attenuated by factors of 5–50 at a bandwidth from 10{sup −3} Hz up to 0.5 Hz, which corresponds to integration times longer than several hundreds of seconds and represent the important timescale for the neutron electric dipole moment measurement. These shielding factors apply to random environmental noise from arbitrary sources. This is achieved via a proportional-integral feedback stabilization system that includes a regularized pseudoinverse matrix of proportionality factors which correlates magnetic field changes at all sensor positions to current changes in the SFC coils.
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.
NASA Technical Reports Server (NTRS)
Wang, T. N. C.; Bell, T. F.
1972-01-01
With the use of a power integral formulation, a study is made of the vlf/elf radiation patterns of arbitrarily oriented electric and magnetic dipoles in a cold lossless multicomponent magnetoplasma. Expressions for the ray patterns are initially developed that apply for arbitrary values of driving frequency, static magnetic-field strength, plasma density, and composition. These expressions are subsequently specialized to vlf/elf radiation in a plasma modeled on the magnetosphere. A series of representative pattern plots are presented for frequencies between the proton and electron gyrofrequencies. These patterns illustrate the fact that focusing effects that arise from the geometrical properties of the refractive index surface tend to dominate the radiation distribution over the entire range from the electron gyrofrequency to 4.6 times the proton gyrofrequency. It is concluded that focusing effects should be of significant importance in the design of a vlf/elf satellite transmitting system in the magnetosphere.
Valiev, R R; Minaev, B F
2016-09-01
The electric dipole transitions between pure spin and mixed spin electronic states are calculated at the XMC-QDPT2 and MCSCF levels of theory, respectively, for different intermolecular distances of the C6H6 and O2 collisional complex. The magnetic dipole transition moment between the mixed-spin ground ("triplet") and the first excited ("singlet") states is calculated by quadratic response at MCSCF level of theory. The obtained results confirm the theory of intensity borrowing and increasing the intensity of electronic transitions in the C6H6 + O2 collision. The calculation of magnetically induced current density is performed for benzene molecule being in contact with O2 at the distances from 3.5 to 4.5 Å. The calculation shows that the aromaticity of benzene is rising due to the conjugation of π-MOs of both molecules. The C6H6 + O2 complex becomes nonaromatic at the short distances (r < 3.5 Å). The computation of static polarizability in the excited electronic states of the C6H6 + O2 collisional complex at various distances supports the theory of red solvatochromic shift of the a → X band. Graphical abstract The C6H6+ O2 collisional complex. PMID:27544142
Heo, Jae Ho
2009-08-01
The model (Lagrangian) with a peculiar extra U(1)[S. M. Barr and I. Dorsner, Phys. Rev. D 72, 015011 (2005); S. M. Barr and A. Khan, Phys. Rev. D 74, 085023 (2006)] is clearly presented. The assigned extra U(1) gauge charges give a strong constraint to build Lagrangians. The Z{sup '} discovery limits are estimated and predicted at the Tevatron and the LHC. The new contributions of the muon anomalous magnetic moment are investigated at one and two loops, and we predict that the deviation from the standard model may be explained. The electron electric dipole moment could also be generated because of the explicit CP-violation effect in the Higgs sector, and a sizable contribution is expected for a moderately sized CP phase [argument of the CP-odd Higgs], 0.1{<=}sin{delta}{<=}1[6 deg. {<=}arg(A){<=}90 deg.].
Lunkenheimer, P.; Muller, J.; Krohns, S.; Schrettle, F.; Loidl, A.; Hartmann, B.; Rommel, R.; de Souza, M.; Hotta, C.; Schlueter, J. A.; Lang, M.
2012-01-01
Multiferroics, showing simultaneous ordering of electrical and magnetic degrees of freedom, are remarkable materials as seen from both the academic and technological points of view. A prominent mechanism of multiferroicity is the spin-driven ferroelectricity, often found in frustrated antiferromagnets with helical spin order. There, as for conventional ferroelectrics, the electrical dipoles arise from an off-centre displacement of ions. However, recently a different mechanism, namely purely electronic ferroelectricity, where charge order breaks inversion symmetry, has attracted considerable interest. Here we provide evidence for ferroelectricity, accompanied by antiferromagnetic spin order, in a two-dimensional organic charge-transfer salt, thus representing a new class of multiferroics. We propose a charge-order-driven mechanism leading to electronic ferroelectricity in this material. Quite unexpectedly for electronic ferroelectrics, dipolar and spin order arise nearly simultaneously. This can be ascribed to the loss of spin frustration induced by the ferroelectric ordering. Hence, here the spin order is driven by the ferroelectricity, in marked contrast to the spin-driven ferroelectricity in helical magnets.
Ahmad, Hasnain; Atulasimha, Jayasimha; Bandyopadhyay, Supriyo
2015-10-01
We report observation of a 'non-volatile' converse magneto-electric effect in elliptical FeGa nanomagnets delineated on a piezoelectric PMN-PT substrate. The nanomagnets are first magnetized with a magnetic field directed along their nominal major axes. Subsequent application of a strong electric field across the piezoelectric substrate generates strain in the substrate, which is partially transferred to the nanomagnets and rotates the magnetizations of some of them away from their initial orientations. The rotated magnetizations remain in their new orientations after the field is removed, resulting in 'non-volatility'. In isolated nanomagnets, the magnetization rotates by <90° upon application of the electric field, but in a dipole-coupled pair consisting of one 'hard' and one 'soft' nanomagnet, which are both initially magnetized in the same direction by the magnetic field, the soft nanomagnet's magnetization rotates by [Formula: see text] upon application of the electric field because of the dipole influence of the hard nanomagnet. This effect can be utilized for a nanomagnetic NOT logic gate. PMID:26373868
NASA Astrophysics Data System (ADS)
Ahmad, Hasnain; Atulasimha, Jayasimha; Bandyopadhyay, Supriyo
2015-10-01
We report observation of a ‘non-volatile’ converse magneto-electric effect in elliptical FeGa nanomagnets delineated on a piezoelectric PMN-PT substrate. The nanomagnets are first magnetized with a magnetic field directed along their nominal major axes. Subsequent application of a strong electric field across the piezoelectric substrate generates strain in the substrate, which is partially transferred to the nanomagnets and rotates the magnetizations of some of them away from their initial orientations. The rotated magnetizations remain in their new orientations after the field is removed, resulting in ‘non-volatility’. In isolated nanomagnets, the magnetization rotates by \\lt 90^\\circ upon application of the electric field, but in a dipole-coupled pair consisting of one ‘hard’ and one ‘soft’ nanomagnet, which are both initially magnetized in the same direction by the magnetic field, the soft nanomagnet’s magnetization rotates by \\gt 90^\\circ upon application of the electric field because of the dipole influence of the hard nanomagnet. This effect can be utilized for a nanomagnetic NOT logic gate.
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.
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.
Atenas, Boris; Pino, Luis A. del; Curilef, Sergio
2014-11-15
We study the classical behavior of an electric dipole in the presence of a uniform magnetic field. Using the Lagrangian formulation, we obtain the equations of motion, whose solutions are represented in terms of Jacobi functions. We also identify two constants of motion, namely, the energy E and a pseudomomentumC{sup →}. We obtain a relation between the constants that allows us to suggest the existence of a type of bound states without turning points, which are called trapped states. These results are consistent with and complementary to previous results. - Highlights: • Bound states without turning points. • Lagrangian Formulation for an electric dipole in a magnetic field. • Motion of the center of mass and trapped states. • Constants of motion: pseudomomentum and energy.
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.
Magnetic field modification of optical magnetic dipoles.
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
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…
Numerical Based Linear Model for Dipole Magnets
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.
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.
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)
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
Magnetic dipole discharges. III. Instabilities
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.
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
Magnetic dipole interactions in crystals
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
Propagation of magnetic dipole radiation through a medium.
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 ϵ_{r} and relative permeability μ_{r}, 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 μ_{r}. 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 μ_{r}. When the real part of μ_{r} 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
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
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.
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.
Quantum electric-dipole liquid on a triangular lattice
Shen, Shi-Peng; Wu, Jia-Chuan; Song, Jun-Da; Sun, Xue-Feng; Yang, Yi-Feng; Chai, Yi-Sheng; Shang, Da-Shan; Wang, Shou-Guo; Scott, James F.; Sun, Young
2016-01-01
Geometric frustration and quantum fluctuations may prohibit the formation of long-range ordering even at the lowest temperature, and therefore liquid-like ground states could be expected. A good example is the quantum spin liquid in frustrated magnets. Geometric frustration and quantum fluctuations can happen beyond magnetic systems. Here we propose that quantum electric-dipole liquids, analogues of quantum spin liquids, could emerge in frustrated dielectrics where antiferroelectrically coupled electric dipoles reside on a triangular lattice. The quantum paraelectric hexaferrite BaFe12O19 with geometric frustration represents a promising candidate for the proposed electric-dipole liquid. We present a series of experimental lines of evidence, including dielectric permittivity, heat capacity and thermal conductivity measured down to 66 mK, to reveal the existence of an unusual liquid-like quantum phase in BaFe12O19, characterized by itinerant low-energy excitations with a small gap. The possible quantum liquids of electric dipoles in frustrated dielectrics open up a fresh playground for fundamental physics. PMID:26843363
Quantum electric-dipole liquid on a triangular lattice
NASA Astrophysics Data System (ADS)
Shen, Shi-Peng; Wu, Jia-Chuan; Song, Jun-Da; Sun, Xue-Feng; Yang, Yi-Feng; Chai, Yi-Sheng; Shang, Da-Shan; Wang, Shou-Guo; Scott, James F.; Sun, Young
2016-02-01
Geometric frustration and quantum fluctuations may prohibit the formation of long-range ordering even at the lowest temperature, and therefore liquid-like ground states could be expected. A good example is the quantum spin liquid in frustrated magnets. Geometric frustration and quantum fluctuations can happen beyond magnetic systems. Here we propose that quantum electric-dipole liquids, analogues of quantum spin liquids, could emerge in frustrated dielectrics where antiferroelectrically coupled electric dipoles reside on a triangular lattice. The quantum paraelectric hexaferrite BaFe12O19 with geometric frustration represents a promising candidate for the proposed electric-dipole liquid. We present a series of experimental lines of evidence, including dielectric permittivity, heat capacity and thermal conductivity measured down to 66 mK, to reveal the existence of an unusual liquid-like quantum phase in BaFe12O19, characterized by itinerant low-energy excitations with a small gap. The possible quantum liquids of electric dipoles in frustrated dielectrics open up a fresh playground for fundamental physics.
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.
Neutron electric dipole moment and CP
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.
NASA Astrophysics Data System (ADS)
Szaller, Dávid; Bordács, Sándor; Kocsis, Vilmos; Rõõm, Toomas; Nagel, Urmas; Kézsmárki, István
2014-05-01
We derive a sum rule to demonstrate that the static magnetoelectric (ME) effect is governed by optical transitions that are simultaneously excited by the electric and magnetic components of light. The ME sum rule is applicable to a broad class of materials lacking the spatial inversion and the time-reversal symmetries, including multiferroic compounds. Due to the dynamical ME effect, the optical excitations in these materials can exhibit directional dichroism, i.e., the absorption coefficient can be different for counter-propagating light beams. According to the ME sum rule, the magnitude of the linear ME effect of a material is mainly determined by the directional dichroism of its low-energy optical excitations. An application of the sum rule to the multiferroic Ba2CoGe2O7, Sr2CoSi2O7, and Ca2CoSi2O7 shows that in these compounds the static ME effect is mostly governed by the directional dichroism of the spin-wave excitations in the giga-terahertz spectral range. On this basis, we argue that the studies of directional dichroism and the application of the ME sum rule promote the synthesis of new materials with large static ME effect.
Search for the electron electric dipole moment
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.
Electric dipole moment of light nuclei
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.
Electric dipole moment of light nuclei
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.
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.
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…
Laser-Induced Magnetic Dipole Spectroscopy.
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
Circular current loops, magnetic dipoles and spherical harmonic analysis.
Alldredge, L.R.
1980-01-01
Spherical harmonic analysis (SHA) is the most used method of describing the Earth's magnetic field, even though spherical harmonic coefficients (SHC) almost completely defy interpretation in terms of real sources. Some moderately successful efforts have been made to represent the field in terms of dipoles placed in the core in an effort to have the model come closer to representing real sources. Dipole sources are only a first approximation to the real sources which are thought to be a very complicated network of electrical currents in the core of the Earth. -Author
Progress towards an electron electric dipole moment measurement with laser-cooled atoms
NASA Astrophysics Data System (ADS)
Solmeyer, Neal
This dissertation recounts the progress made towards a measurement of the electron electric dipole moment. The existence of a permanent electric dipole moment of any fundamental particle would imply that both time reversal and parity invariance are violated. If an electric dipole moment were measured within current experimental limits it would be the first direct evidence for physics beyond the standard model. For our measurement we use laser-cooled alkali atoms trapped in a pair of 1D optical lattices. The lattices run through three electric field plates so that the two groups of atoms see opposing electric fields. The measurement chamber is surrounded by a four layer mu-metal magnetic shield. Under electric field quantization, the atoms are prepared in a superposition of magnetic sublevels that is sensitive to the electron electric dipole moment in Ramsey-like spectroscopy. The experiment requires very large electric fields and very small magnetic fields. Engineering a system compatible with both of these goals simultaneously is not trivial. Searches for electric dipole moments using neutral atoms in optical lattices have much longer possible interaction times and potentially give more precise information about the inherent symmetry breaking than other methods. This comes at the cost of a higher sensitivity to magnetic fields and possible sources of error associated with the trapping light. If noise and systematic errors can be controlled to our design specifications our experiment will significantly improve the current experimental limit of the electron electric dipole moment.
The radiofrequency magnetic dipole discharge
NASA Astrophysics Data System (ADS)
Martines, E.; Zuin, M.; Marcante, M.; Cavazzana, R.; Fassina, A.; Spolaore, M.
2016-05-01
This paper describes a novel and simple concept of plasma source, which is able to produce a radiofrequency magnetized discharge with minimal power requirements. The source is based on the magnetron concept and uses a permanent magnet as an active electrode. The dipolar field produced by the magnet confines the electrons, which cause further ionization, thus producing a toroidally shaped plasma in the equatorial region around the electrode. A plasma can be ignited with such scheme with power levels as low as 5 W. Paschen curves have been built for four different working gases, showing that in Helium or Neon, plasma breakdown is easily obtained also at atmospheric pressure. The plasma properties have been measured using a balanced Langmuir probe, showing that the electron temperature is around 3-4 eV and higher in the cathode proximity. Plasma densities of the order of 1016 m-3 have been obtained, with a good positive scaling with applied power. Overall, the electron pressure appears to be strongly correlated with the magnetic field magnitude in the measurement point.
Sur, Chiranjib; Chaudhuri, Rajat K.
2007-09-15
Searching for an accurate optical clock which can serve as a better time standard than the present-day atomic clock is highly demanding from several areas of science and technology. Several attempts have been made to build more accurate clocks with different ion species. In this paper, we discuss the electric quadrupole and hyperfine shifts in the 5d{sup 9}6s{sup 2} {sup 2}D{sub 5/2}(F=0,m{sub F}=0){r_reversible}5d{sup 10}6s {sup 2}S{sub 1/2}(F=2,m{sub F}=0) clock transition in {sup 199}Hg{sup +}, one of the most promising candidates for next-generation optical clocks. We have applied Fock-space unitary coupled-cluster theory to study the electric quadrupole moment of the 5d{sup 9}6s{sup 2} {sup 2}D{sub 5/2} state and magnetic dipole hyperfine constants of 5d{sup 9}6s{sup 2} {sup 2}D{sub 3/2,5/2} and 5d{sup 10}6s{sup 1} {sup 2}S{sub 1/2} states, respectively, of {sup 199}Hg{sup +}. We have also compared our results with available data. To the best of our knowledge, this is the first time a variant of coupled-cluster theories has been applied to study these kinds of properties of Hg{sup +} and is the most accurate estimate of these quantities to date.
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.
Draine, B. T.; Hensley, Brandon
2012-09-20
The Small Magellanic Cloud (SMC) has surprisingly strong submillimeter- and millimeter-wavelength emission that is inconsistent with standard dust models, including those with emission from spinning dust. Here, we show that the emission from the SMC may be understood if the interstellar dust mixture includes magnetic nanoparticles, emitting magnetic dipole radiation resulting from thermal fluctuations in the magnetization. The magnetic grains can be metallic iron, magnetite Fe{sub 3}O{sub 4}, or maghemite {gamma}-Fe{sub 2}O{sub 3}. The required mass of iron is consistent with elemental abundance constraints. The magnetic dipole emission is predicted to be polarized orthogonally to the normal electric dipole radiation if the nanoparticles are inclusions in larger grains. We speculate that other low-metallicity galaxies may also have a large fraction of the interstellar Fe in magnetic materials.
Revised cross section for RHIC dipole magnets
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.
Local electric dipole moments: A generalized approach.
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
Large muon electric dipole moment from flavor?
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.
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.
Electric dipole moments (EDM) of ionic atoms
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.
Neutron electric dipole moment and dressed spin
NASA Astrophysics Data System (ADS)
Chu, Ping-Han
The neutron electric dipole moment (EDM) experiment has played a unique role in examining the violation of fundamental symmetries and understanding the nature of electroweak and strong interaction. A non-zero neutron EDM is one of direct evidence for CP and T violation and has the potential to reveal the origin of CP violation and to explore physics beyond the Standard Model. A new neutron EDM experiment will be built to improve a factor of 100 by using a novel technique of ultra-cold neutrons(UCN) in superfluid 4He at the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL). In the experiment, 3He in the measurement cell will be used as a neutron spin analyzer and a comagnetometer. The absorption between UCN and 3He atoms will emit scintillation light in the superfluid 4He depending on the angle between nuclear spins of two particles. Consequently, the neutron precession frequency can be derived by the scintillation light amplitude. Furthermore, the 3He precession frequency can be measured by the superconducting quantum interference device (SQUID). A dressed-spin technique will also be applied to measure the small precession frequency change due to a non-zero neutron EDM. The dressed-spin technique is used to modify the effective precession frequencies of neutrons and 3He atoms to make them equal by applying an oscillatory field (dressing field) that is perpendicular to the static magnetic field. The phenomenon of the dressed spin for 3He in a cell should be demonstrated before the proposed neutron EDM experiment. A successful measurement over a broad range of the amplitude and frequency of the dressing field was done at the University of Illinois. The observed effects can be explained by using quantum optics formalism. The formalism is diagonalized to solve the solution and confirms the data. In addition, the application of the dressed-spin technique was investigated. The modulation and the feedback loop technique should be considered with
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.
SEMERTZIDIS, Y.K.
2005-05-23
We have shown that the study of dipole moments, both magnetic and electric, in storage rings offer unique opportunities in probing physics beyond the Standard Model (SM). Both methods use similar techniques (particle and spin precession in magnetic storage rings). We are currently investigating the systematic errors associated with the resonance electric dipole moment (EDM) method. So far it looks very promising.
Magnetic field decay in model SSC dipoles
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.
Development of a simulation for measuring neutron electric dipole moment
NASA Astrophysics Data System (ADS)
Katayama, Ryo; Mishima, Kenji; Yamashita, Satoru; Sakurai, Dai; Kitaguchi, Masaaki; Yoshioka, Tamaki; Seki, Yoshichika
2014-07-01
The neutron electric dipole moment (nEDM) is sensitive to new physics beyond the standard model and could prove to be a new source of CP violation. Several experiments are being planned worldwide for its high-precision measurement. The nEDM is measured as the ultracold neutron (UCN) spin precession in a storage bottle under homogeneous electric and magnetic fields. In nEDM measurement, the systematic uncertainties are due to the motion of the UCNs, the geometry of the measurement system, and inhomogeneous electric and magnetic fields. Therefore, it is essential to quantitatively understand these effects in order to reduce them. Geant4UCN is an ideal simulation framework because it can compute the UCN trajectory, evaluate the time evolution of the spin precession due to arbitrary electric and magnetic fields, and define the storage geometry flexibly. We checked how accurately Geant4UCN can calculate the spin precession. We found that because of rounding errors, it cannot simulate it accurately enough for nEDM experiments, assuming homogeneous electric and magnetic fields with strengths of 10 kV/cm and 1 μT, respectively, and 100 s of storage. In this paper, we report on its discrepancies and describe a solution.
Electron electric-dipole-moment experiment using electric-field quantized slow cesium atoms
Amini, Jason M.; Munger, Charles T. Jr.; Gould, Harvey
2007-06-15
A proof-of-principle electron electric-dipole-moment (e-EDM) experiment using slow cesium atoms, nulled magnetic fields, and electric-field quantization has been performed. With the ambient magnetic fields seen by the atoms reduced to less than 200 pT, an electric field of 6 MV/m lifts the degeneracy between states of unequal |m{sub F}| and, along with the low ({approx_equal}3 m/s) velocity, suppresses the systematic effect from the motional magnetic field. The low velocity and small residual magnetic field have made it possible to induce transitions between states and to perform state preparation, analysis, and detection in regions free of applied static magnetic and electric fields. This experiment demonstrates techniques that may be used to improve the e-EDM limit by two orders of magnitude, but it is not in itself a sensitive e-EDM search, mostly due to limitations of the laser system.
Pulsar Pair Cascades in a Distorted Magnetic Dipole Field
NASA Technical Reports Server (NTRS)
Harding, Alice K.; Muslimov, Alex G.
2010-01-01
We investigate the effect of a distorted neutron star dipole magnetic field on pulsar pair cascade multiplicity and pair death lines. Using a simple model for a distorted dipole field that produces an offset polar cap (PC), we derive the accelerating electric field above the PC in space-charge-limited flow. We find that even a modest azimuthally asymmetric distortion can significantly increase the accelerating electric field on one side of the PC and, combined with a smaller field line radius of curvature, leads to larger pair multiplicity. The death line for producing pairs by curvature radiation moves downward in the P-P-dot diagram, allowing high pair multiplicities in a larger percentage of the radio pulsar population. These results could have important implications for the radio pulsar population, high energy pulsed emission, and the pulsar contribution to cosmic ray positrons.
Measurement of electric dipole moments at storage rings
NASA Astrophysics Data System (ADS)
Jörg Pretz JEDI Collaboration
2015-11-01
The electric dipole moment (EDM) is a fundamental property of a particle, like mass, charge and magnetic moment. What makes this property in particular interesting is the fact that a fundamental particle can only acquire an EDM via {P} and {T} violating processes. EDM measurements contribute to the understanding of the matter over anti-matter dominance in the universe, a question closely related to the violation of fundamental symmetries. Up to now measurements of EDMs have concentrated on neutral particles. Charged particle EDMs can be measured at storage ring. Plans at Forschungszentrum Jülich and results of first test measurements at the COoler SYnchrotron COSY will be presented.
Brownian dipole rotator in alternating electric field.
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
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.
Search for a Neutron Electric Dipole Moment
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
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".
Nuclear electric dipole moment of 3He
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.
Search for the Neutron Electric Dipole Moment
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'.
A search for the electric dipole of the electron
Abdullah, K.F.
1989-08-01
We report a new upper limit on the electric dipole moment (EDM) of the electron of d{sub e} = 0.1 {plus minus} 3.2 {times} 10{sup {minus}26} e-cm. This precision is one hundred times better than any previously published limit and a factor of two better than that of unofficial reports. Recently there has been a great deal of theoretical interest in the possibility of a non-zero electron EDM. Models such as the left-right-symmetric Standard Model and an off-standard'' model with new heavy neutrinos are constrained by the new limit on d{sub e}. A non-zero electron EDM would violate the time reversal and parity space-time symmetries. T-violation was observed in neutral kaon decay and is still not fully explained by the Standard Model. Our experimental technique involves searching for an energy shift, linear in applied electric field, between the m{sub F} = 1 and m{sub F} = {minus}1 magnetic sublevels of the F=1 hyperfine level of the 6{sup 2}P{sub 1/2} ground state of atomic thallium. If the electron has a non-zero EDM, this thallium state will exhibit an atomic electric dipole moment that is roughly 600 times larger. The energy shift is detected with the technique of magnetic resonance spectroscopy, employing separated oscillating fields, applied to an atomic beam of thallium. In the approach, any relative phase-shift between the m{sub F} = {plus minus}1 components of the F=1 wavefunction acquired by the atom as it travels through an electric field is detected through interference with two separate oscillating magnetic fields located on either side of the electric field. The new level of precision is achieved through several improvements on previous experiments including employment of a vertical apparatus, two opposing atomic beams, and optical pumping for atomic state selection and analysis.
Magnetic dipole discharges. I. Basic properties
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.
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.
Electron electric dipole moment experiment using electric-fieldquantized slow cesium atoms
Amini, Jason M.; Munger Jr., Charles T.; Gould, Harvey.
2007-04-05
A proof-of-principle electron electric dipole moment (e-EDM)experiment using slow cesium atoms, nulled magnetic fields, and electricfield quantization has been performed. With the ambient magnetic fieldsseen by the atoms reduced to less than 200 pT, an electric field of 6MV/m lifts the degeneracy between states of unequal lbar mF rbar and,along with the low (approximately 3 m/s) velocity, suppresses thesystematic effect from the motional magnetic field. The low velocity andsmall residual magnetic field have made it possible to induce transitionsbetween states and to perform state preparation, analysis, and detectionin regions free of applied static magnetic and electric fields. Thisexperiment demonstrates techniques that may be used to improve the e-EDMlimit by two orders of magnitude, but it is not in itself a sensitivee-EDM search, mostly due to limitations of the laser system.
Communication: Permanent dipoles contribute to electric polarization in chiral NMR spectra
Buckingham, A. David
2014-01-07
Nuclear magnetic resonance spectroscopy is blind to chirality because the spectra of a molecule and its mirror image are identical unless the environment is chiral. However, precessing nuclear magnetic moments in chiral molecules in a strong magnetic field induce an electric polarization through the nuclear magnetic shielding polarizability. This effect is equal and opposite for a molecule and its mirror image but is small and has not yet been observed. It is shown that the permanent electric dipole moment of a chiral molecule is partially oriented through the antisymmetric part of the nuclear magnetic shielding tensor, causing the electric dipole to precess with the nuclear magnetic moment and producing a much larger temperature-dependent electric polarization with better prospects of detection.
Concentric Titled Double-Helix Dipole Magnets
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.
Thomas, Martin; Kirchner, Barbara
2016-02-01
We present a new approach for calculating vibrational circular dichroism spectra by ab initio molecular dynamics. In the context of molecular dynamics, these spectra are given by the Fourier transform of the cross-correlation function of magnetic dipole moment and electric dipole moment. We obtain the magnetic dipole moment from the electric current density according to the classical definition. The electric current density is computed by solving a partial differential equation derived from the continuity equation and the condition that eddy currents should be absent. In combination with a radical Voronoi tessellation, this yields an individual magnetic dipole moment for each molecule in a bulk phase simulation. Using the chiral alcohol 2-butanol as an example, we show that experimental spectra are reproduced very well. Our approach requires knowing only the electron density in each simulation step, and it is not restricted to any particular electronic structure method. PMID:26771403
Pair Cascades and Deathlines in Offset Magnetic Dipole Fields
NASA Technical Reports Server (NTRS)
Harding, Alice; Muslimov, Alex
2010-01-01
We investigate electron-positron pair cascades in a dipole magnetic field whose axis is offset from the neutron star center. In such a field geometry, the polar cap is displaced from the neutron star symmetry axis and the field line radius of curvature is modified. Using the modified parallel electric field near the polar cap of an offset dipole, we simulate pair cascades to determine the pair deathlines and pair multiplicities as a function of the offset parameter. We find that the pair multiplicity can change dramatically with a modest offset, with a significant increase on one side of the polar cap. Lower pair deathlines allow a larger fraction of the pulsar population, that include old and millisecond pulsars, to produce cascades with high multiplicity.
Space propulsion by fusion in a magnetic dipole
Teller, E.; Glass, A.J.; Fowler, T.K. ); Hasegawa, A. ); Santarius, J.F. . Fusion Technology Inst.)
1991-07-15
The unique advantages of fusion rocket propulsion systems for distant missions are explored using the magnetic dipole configurations as an example. The dipole is found to have features well suited to space applications. Parameters are presented for a system producing a specific power of kW/kg, capable of interplanetary flights to Mars in 90 days and to Jupiter in a year, and of extra-solar-system flights to 1000 astronomical units (the Tau mission) in 20 years. This is about 10 times better specific power performance than nuclear electric fission systems. Possibilities to further increase the specific power toward 10 kW/kg are discussed, as is an approach to implementing the concept through proof-testing on the moon. 20 refs., 14 figs., 2 tabs.
Development of a Francium Electron Electric Dipole Moment Experiment
NASA Astrophysics Data System (ADS)
Munger, Charles T., Jr.; Feinberg, B.; Gould, Harvey; Kalnins, Juris; Nishimura, Hiroshi; Jentschura, Ulrich; Behr, John; Pearson, Matt
2014-09-01
An experiment to discover or rule out a permanent electric dipole moment (EDM) of the electron, at a sensitivity well beyond the present experimental limit, is being developed. The experiment will use 211Fr, obtainable online at TRIUMF at rates of 109/s, in a laser-cooled fountain. The experiment is done in free space and free fall, with an electric field, but no applied magnetic field, between optical state preparation and analysis. The relation between an electron EDM and an EDM of a francium atom has recently been recalculated using field theory alone (Blundell, Griffith & Sapirstein, Phys. Rev. D 86, 025023 [2012]), confirming previous atomic physics calculations and removing any ambiguity in the experimental interpretation.
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.
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.
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.
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.
Electric dipole polarizability and the neutral skin
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.
Nuclear Electric Dipole Moment of 3He
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.
The search for permanent electric dipole moments
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.
Nuclear Electric Dipole Moment of ^{3}_He
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.
Geometric quantum phase for displaced states for a particle with an induced electric dipole moment
NASA Astrophysics Data System (ADS)
Lemos de Melo, J.; Bakke, K.; Furtado, C.
2016-07-01
Basing on the analogue Landau levels for a neutral particle possessing an induced electric dipole moment, we show that displaced states can be built in the presence of electric and magnetic fields. Besides, the Berry phase associated with these displaced quantum states is obtained by performing an adiabatic cyclic evolution in series of paths in parameter space.
Electric Dipole Moment Experiment Systematic from Electric Field Discharge Current
NASA Astrophysics Data System (ADS)
Feinberg, B.; Gould, Harvey
2014-09-01
A magnetic field, in the direction of the electric field and synchronous with the electric field reversal, will mimic an EDM signal. One might expect a discharge across the electric field plates to produce magnetic fields with only small or vanishing components parallel to the electric field, minimizing its systematic effect. Our experimental model, using simulated discharge currents, found otherwise: the discharge current may be at an angle to the normal, and thus generate a normal magnetic field. Comparison of data from the experimental model with the results from calculations will be presented, along with estimates of the time-averaged normal magnetic field seen by atoms in an electron EDM experiment using a fountain of laser-cooled francium, as a function of discharge current.
The electric dipole moment of cobalt monoxide, CoO
Zhuang, Xiujuan; Steimle, Timothy C.
2014-03-28
A number of low-rotational lines of the E{sup 4}Δ{sub 7/2} ← X{sup 4}Δ{sub 7/2} (1,0) band system of cobalt monoxide, CoO, were recorded field free and in the presence of a static electric field. The magnetic hyperfine parameter, h{sub 7/2}, and the electron quadrupole parameter, eQq{sub 0}, for the E{sup 4}Δ{sub 7/2}(υ = 1) state were optimized from the analysis of the field-free spectrum. The permanent electric dipole moment, μ{sup -vector}{sub el}, for the X{sup 4}Δ{sub 7/2} (υ = 0) and E{sup 4}Δ{sub 7/2} (υ = 1) states were determined to be 4.18 ± 0.05 D and 3.28 ± 0.05 D, respectively, from the analysis of the observed Stark spectra of F′ = 7 ← F″ = 6 branch feature in the Q(7/2) line and the F′ = 8 ← F″ = 7 branch feature in the R(7/2) line. The measured dipole moments of CoO are compared to those from theoretical predictions and the trend across the 3d-metal monoxide series discussed.
Axion Induced Oscillating Electric Dipole Moment of the Electron
Hill, Christopher T.
2016-01-12
A cosmic axion, via the electromagnetic anomaly, induces an oscillating electric dipole for the electron of frequency ma and strength ~(few) x 10-32 e-cm, two orders of magnitude above the nucleon, and within a few orders of magnitude of the present standard model constant limit. We give a detailed study of this phenomenon via the interaction of the cosmic axion, through the electromagnetic anomaly, with particular emphasis on the decoupling limit of the axion, ∂ta(t) ∝ mα → 0. The analysis is subtle, and we find the general form of the action involves a local contact interaction and a nonlocalmore » contribution, analogous to the “transverse current” in QED, that enforces the decoupling limit. We carefully derive the effective action in the Pauli-Schroedinger non-relativistic formalism, and in Georgi’s heavy quark formalism adapted to the “heavy electron” (me >> ma). We compute the electric dipole radiation emitted by free electrons, magnets and currents, immersed in the cosmic axion field, and discuss experimental configurations that may yield a detectable signal.« less
Search for a Permanent Electric Dipole Moment of 225Ra
NASA Astrophysics Data System (ADS)
Kalita, Mukut Ranjan
The observation of a permanent electric dipole moment (EDM) in a non-degenerate system would indicate the violation of discrete symmetries of Time reversal (T) or combined application of Charge (C) and Parity (P) symmetry violation through the CPT theorem. The diamagnetic 225Ra atom with nuclear spin I=1/2 is a favorable candidate for an EDM search. Experimental sensitivity to its EDM is enhanced due to its high atomic mass and the increased Schiff moment of its octupole deformed nucleus. An experimental setup is developed where laser cooled neutral radium atoms are collected in a magneto-optical trap (MOT). The collected atoms are transported 1 meter with a far off-resonant optical dipole trap (ODT) and then the atoms are transferred to a second standing-wave ODT in an experimental chamber. The atoms are then optically polarized and allowed to Larmor precess in parallel and antiparallel electric and magnetic fields. The difference between the Larmor precession frequency for parallel and antiparallel fields is experimentally determined to measure the EDM. This thesis is about the first measurement of the EDM of the 225Ra atom where an upper limit of |d(225Ra)| < 5.0 x 10-22 e·cm (95% confidence) is reached. Keywords: Permanent EDM, CP violation, laser cooling and trapping, rare isotopes, radium.
Helical dipole magnets for polarized protons in RHIC
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.
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.
Electric dipole transitions between Gamow-Teller and spin-dipole states
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}
Limit on the Electron Electric Dipole Moment in Gadolinium-Iron Garnet
Heidenreich, B.J.; Elliott, O.T.; Charney, N.D.; Virgien, K.A.; Bridges, A.W.; McKeon, M.A.; Peck, S.K.; Krause, D. Jr.; Gordon, J.E.; Hunter, L.R.; Lamoreaux, S.K.
2005-12-16
A new method for the detection of the electron electric dipole moment (EDM) using a solid is described. The method involves the measurement of a voltage induced across the solid by the alignment of the sample's magnetic dipoles in an applied magnetic field, H. A first application of the method to GdIG has resulted in a limit on the electron EDM of 5x10{sup -24}e cm, which is a factor of 40 below the limit obtained from the only previous solid-state EDM experiment. The result is limited by the imperfect discrimination of an unexpectedly large voltage that is even upon the reversal of the sample magnetization.
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.
QED vacuum fluctuations and induced electric dipole moment of the neutron
Dominguez, C. A.; Falomir, H.; Ipinza, M.; Loewe, M.; Kohler, S.; Rojas, J. C.
2009-08-01
Quantum fluctuations in the QED vacuum generate nonlinear effects, such as peculiar induced electromagnetic fields. In particular, we show here that an electrically neutral particle, possessing a magnetic dipole moment, develops an induced electric dipole-type moment with unusual angular dependence, when immersed in a quasistatic, constant external electric field. The calculation of this effect is done in the framework of the Euler-Heisenberg effective QED Lagrangian, corresponding to the weak field asymptotic expansion of the effective action to one-loop order. It is argued that the neutron might be a good candidate to probe this signal of nonlinearity in QED.
Magnetic field homogeneity perturbations in finite Halbach dipole magnets.
Turek, Krzysztof; Liszkowski, Piotr
2014-01-01
Halbach hollow cylinder dipole magnets of a low or relatively low aspect ratio attract considerable attention due to their applications, among others, in compact NMR and MRI systems for investigating small objects. However, a complete mathematical framework for the analysis of magnetic fields in these magnets has been developed only for their infinitely long precursors. In such a case the analysis is reduced to two-dimensions (2D). The paper details the analysis of the 3D magnetic field in the Halbach dipole cylinders of a finite length. The analysis is based on three equations in which the components of the magnetic flux density Bx, By and Bz are expanded to infinite power series of the radial coordinate r. The zeroth term in the series corresponds to a homogeneous magnetic field Bc, which is perturbed by the higher order terms due to a finite magnet length. This set of equations is supplemented with an equation for the field profile B(z) along the magnet axis, presented for the first time. It is demonstrated that the geometrical factors in the coefficients of particular powers of r, defined by intricate integrals are the coefficients of the Taylor expansion of the homogeneity profile (B(z)-Bc)/Bc. As a consequence, the components of B can be easily calculated with an arbitrary accuracy. In order to describe perturbations of the field due to segmentation, two additional equations are borrowed from the 2D theory. It is shown that the 2D approach to the perturbations generated by the segmentation can be applied to the 3D Halbach structures unless r is not too close to the inner radius of the cylinder ri. The mathematical framework presented in the paper was verified with great precision by computations of B by a highly accurate integration of the magnetostatic Coulomb law and utilized to analyze the inhomogeneity of the magnetic field in the magnet with the accuracy better than 1 ppm. PMID:24316186
Development of Cellular Magnetic Dipoles in Magnetotactic Bacteria
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
Measuring the Electron Electric Dipole Moment Using Ytterbium Fluoride Molecules
NASA Astrophysics Data System (ADS)
Smallman, I. J.; Devlin, J. A.; Kara, D. M.; Hudson, J. J.; Sauer, B. E.; Tarbutt, M. R.; Hinds, E. A.
2013-06-01
It is well known that the existence of an electron electric dipole moment (eEDM) would violate time reversal symmetry. The Standard Model predicts an eEDM less than 10^{-38}e.cm, however many popular extensions predict values in the range 10^{-29}-10^{-24}e.cm. Our experiment currently has the potential to measure eEDMs down to approximately 10^{-29}e.cm, making it a precise probe for T-violation and physics beyond the Standard Model. We measure the eEDM by performing a type of separated oscillating field interferometry on a pulsed beam of YbF. The molecules are prepared such that the molecular spin is oriented perpendicular to an applied strong (10kV/cm) electric field. The spin is then allowed to precess about the electric field axis over a 0.5ms interaction period. We measure this angle of rotation, which is directly proportional to the eEDM. In order to measure the eEDM precisely and without error we use a complex switching technique wherein certain parameters, including the applied electric and magnetic fields, are reversed between individual molecular pulses. I will present our current technique and our most recent world leading result.
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.
Reply to "Comment on `Axion Induced Oscillating Electric Dipole Moments' "
Hill, Christopher T.
2015-10-19
A recent paper of Flambaum, Roberts and Stadnik, [1], claims there is no induced oscillating electric dipole moment (OEDM), eg, for the electron, arising from the oscillating cosmic axion background via the anomaly. This claim is based upon the assumption that electric dipoles always be defined by their coupling to static (constant in time) electric fields. The relevant Feynman diagram, as computed by [1], then becomes a total divergence, and vanishes in momentum space. However, an OEDM does arise from the anomaly, coupled to time dependent electric fields. It shares the decoupling properties with the anomaly. The full action, in an arbitrary gauge, was computed in [2], [3]. It is nonvanishing with a time dependent outgoing photon, and yields physics, eg, electric dipole radiation of an electron immersed in a cosmic axion field.
Elementary quantum mechanics of the neutron with an electric dipole moment.
Baym, Gordon; Beck, D H
2016-07-01
The neutron, in addition to possibly having a permanent electric dipole moment as a consequence of violation of time-reversal invariance, develops an induced electric dipole moment in the presence of an external electric field. We present here a unified nonrelativistic description of these two phenomena, in which the dipole moment operator, [Formula: see text], is not constrained to lie along the spin operator. Although the expectation value of [Formula: see text] in the neutron is less than [Formula: see text] of the neutron radius, [Formula: see text], the expectation value of [Formula: see text] is of order [Formula: see text] We determine the spin motion in external electric and magnetic fields, as used in past and future searches for a permanent dipole moment, and show that the neutron electric polarizability, although entering the neutron energy in an external electric field, does not affect the spin motion. In a simple nonrelativistic model we show that the expectation value of the permanent dipole is, to lowest order, proportional to the product of the time-reversal-violating coupling strength and the electric polarizability of the neutron. PMID:27325765
Electric dipole sheets in BaTiO3/BaZrO3 superlattices
NASA Astrophysics Data System (ADS)
Jiang, Zhijun; Xu, Bin; Li, Fei; Wang, Dawei; Jia, C.-L.
2015-01-01
We investigate two-dimensional electric dipole sheets in the superlattice made of BaTiO3 and BaZrO3 using first-principles-based Monte Carlo simulations and density functional calculations. Electric dipole domains and complex patterns are observed and complex dipole structures with various symmetries (e.g., P m a 2 ,C m c m , and P m c 21 ) are further confirmed by density functional calculations, which are found to be almost degenerate in energy with the ferroelectric ground state of the A m m 2 symmetry, therefore strongly resembling magnetic sheets. More complex dipole patterns, including vortices and antivortices, are also observed, which may constitute the intermediate states that overcome the high-energy barrier of different polarization orientations previously predicted by A. I. Lebedev [Phys. Solid State 55, 1198 (2013), 10.1134/S1063783413060218]. We also show that such system possesses large electrostrictive effects that may be technologically important.
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.
Spacecraft Attitude Stabilization with Piecewise-Constant Magnetic Dipole Moment
NASA Astrophysics Data System (ADS)
Celani, Fabio
2016-05-01
In actual implementations of magnetic control laws for spacecraft attitude stabilization, the time in which Earth magnetic field is measured must be separated from the time in which magnetic dipole moment is generated. The latter separation translates into the constraint of being able to genere only piecewise-constant magnetic dipole moment. In this work we present attitude stabilization laws using only magnetic actuators that take into account of the latter aspect. Both a state feedback and an output feedback are presented, and it is shown that the proposed design allows for a systematic selection of the sampling period.
Enhancing Eu(3+) magnetic dipole emission by resonant plasmonic nanostructures.
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 Eu^{3+} 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 Eu^{3+} 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
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.
Dual aperture dipole magnet with second harmonic component
Praeg, W.F.
1983-08-31
An improved dual aperture dipole electromagnet includes a second-harmonic frequency magnetic guide field winding which surrounds first harmonic frequency magnetic guide field windings associated with each aperture. The second harmonic winding and the first harmonic windings cooperate to produce resultant magnetic waveforms in the apertures which have extended acceleration and shortened reset portions of electromagnet operation.
Dual aperture dipole magnet with second harmonic component
Praeg, Walter F.
1985-01-01
An improved dual aperture dipole electromagnet includes a second-harmonic frequency magnetic guide field winding which surrounds first harmonic frequency magnetic guide field windings associated with each aperture. The second harmonic winding and the first harmonic windings cooperate to produce resultant magnetic waveforms in the apertures which have extended acceleration and shortened reset portions of electromagnet operation.
Khromova, Irina; Kužel, Petr; Brener, Igal; Reno, John L.; Chung Seu, U-Chan; Elissalde, Catherine; Maglione, Mario; Mounaix, Patrick; Mitrofanov, Oleg
2016-06-27
Monocrystalline titanium dioxide (TiO2) micro-spheres support two orthogonal magnetic dipole modes at terahertz (THz) frequencies due to strong dielectric anisotropy. For the first time, we experimentally detected the splitting of the first Mie mode in spheres of radii inline imagem through near-field time-domain THz spectroscopy. By fitting the Fano lineshape model to the experimentally obtained spectra of the electric field detected by the sub-wavelength aperture probe, we found that the magnetic dipole resonances in TiO2 spheres have narrow linewidths of only tens of gigahertz. Lastly, anisotropic TiO2 micro-resonators can be used to enhance the interplay of magnetic and electric dipolemore » resonances in the emerging THz all-dielectric metamaterial technology.« less
Compact Electric- And Magnetic-Field Sensor
NASA Technical Reports Server (NTRS)
Winterhalter, Daniel; Smith, Edward
1994-01-01
Compact sensor measures both electric and magnetic fields. Includes both short electric-field dipole and search-coil magnetometer. Three mounted orthogonally providing triaxial measurements of electromagnetic field at frequencies ranging from near 0 to about 10 kHz.
Gyre-driven decay of the Earth's magnetic dipole.
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
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.
Gyre-driven decay of the Earth's magnetic dipole
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
Antenna impedance measurements in a magnetized plasma. II. Dipole antenna
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.
Quantitative analysis on electric dipole energy in Rashba band splitting.
Hong, Jisook; Rhim, Jun-Won; Kim, Changyoung; Ryong Park, Seung; Hoon Shim, Ji
2015-01-01
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. PMID:26323493
Quantitative analysis on electric dipole energy in Rashba band splitting
Hong, Jisook; Rhim, Jun-Won; Kim, Changyoung; Ryong Park, Seung; Hoon Shim, Ji
2015-01-01
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. PMID:26323493
Mercury monohalides: suitability for electron electric dipole moment searches.
Prasannaa, V S; Vutha, A C; Abe, M; Das, B P
2015-05-01
Heavy polar diatomic molecules are the primary tools for searching for the T-violating permanent electric dipole moment of the electron (eEDM). Valence electrons in some molecules experience extremely large effective electric fields due to relativistic interactions. These large effective electric fields are crucial to the success of polar-molecule-based eEDM search experiments. Here we report on the results of relativistic ab initio calculations of the effective electric fields in a series of molecules that are highly sensitive to an eEDM, the mercury monohalides (HgF, HgCl, HgBr, and HgI). We study the influence of the halide anions on E_{eff}, and identify HgBr and HgI as attractive candidates for future electric dipole moment search experiments. PMID:26000997
Mercury Monohalides: Suitability for Electron Electric Dipole Moment Searches
NASA Astrophysics Data System (ADS)
Prasannaa, V. S.; Vutha, A. C.; Abe, M.; Das, B. P.
2015-05-01
Heavy polar diatomic molecules are the primary tools for searching for the T -violating permanent electric dipole moment of the electron (eEDM). Valence electrons in some molecules experience extremely large effective electric fields due to relativistic interactions. These large effective electric fields are crucial to the success of polar-molecule-based eEDM search experiments. Here we report on the results of relativistic ab initio calculations of the effective electric fields in a series of molecules that are highly sensitive to an eEDM, the mercury monohalides (HgF, HgCl, HgBr, and HgI). We study the influence of the halide anions on Eeff, and identify HgBr and HgI as attractive candidates for future electric dipole moment search experiments.
Improved limit on the 225Ra electric dipole moment
NASA Astrophysics Data System (ADS)
Bishof, Michael; Parker, Richard H.; Bailey, Kevin G.; Greene, John P.; Holt, Roy J.; Kalita, Mukut R.; Korsch, Wolfgang; Lemke, Nathan D.; Lu, Zheng-Tian; Mueller, Peter; O'Connor, Thomas P.; Singh, Jaideep T.; Dietrich, Matthew R.
2016-08-01
Background: Octupole-deformed nuclei, such as that of 225Ra, are expected to amplify observable atomic electric dipole moments (EDMs) that arise from time-reversal and parity-violating interactions in the nuclear medium. In 2015 we reported the first "proof-of-principle" measurement of the 225Ra atomic EDM. Purpose: This work reports on the first of several experimental upgrades to improve the statistical sensitivity of our 225Ra EDM measurements by orders of magnitude and evaluates systematic effects that contribute to current and future levels of experimental sensitivity. Method: Laser-cooled and trapped 225Ra atoms are held between two high-voltage electrodes in an ultrahigh-vacuum chamber at the center of a magnetically-shielded environment. We observe Larmor precession in a uniform magnetic field using nuclear-spin-dependent laser light scattering and look for a phase shift proportional to the applied electric field, which indicates the existence of an EDM. The main improvement to our measurement technique is an order-of-magnitude increase in spin-precession time, which is enabled by an improved vacuum system and a reduction in trap-induced heating. Results: We have measured the 225Ra atomic EDM to be less than 1.4 ×10-23e cm (95 % confidence upper limit), which is a factor of 36 improvement over our previous result. Conclusions: Our evaluation of systematic effects shows that this measurement is completely limited by statistical uncertainty. Combining this measurement technique with planned experimental upgrades, we project a statistical sensitivity at the 1 ×10-28e cm level and a total systematic uncertainty at the 4 ×10-29e cm level.
Atom-Pair Kinetics with Strong Electric-Dipole Interactions
NASA Astrophysics Data System (ADS)
Thaicharoen, N.; Gonçalves, L. F.; Raithel, G.
2016-05-01
Rydberg-atom ensembles are switched from a weakly to a strongly interacting regime via adiabatic transformation of the atoms from an approximately nonpolar into a highly dipolar quantum state. The resultant electric dipole-dipole forces are probed using a device akin to a field ion microscope. Ion imaging and pair-correlation analysis reveal the kinetics of the interacting atoms. Dumbbell-shaped pair-correlation images demonstrate the anisotropy of the binary dipolar force. The dipolar C3 coefficient, derived from the time dependence of the images, agrees with the value calculated from the permanent electric-dipole moment of the atoms. The results indicate many-body dynamics akin to disorder-induced heating in strongly coupled particle systems.
Atom-Pair Kinetics with Strong Electric-Dipole Interactions.
Thaicharoen, N; Gonçalves, L F; Raithel, G
2016-05-27
Rydberg-atom ensembles are switched from a weakly to a strongly interacting regime via adiabatic transformation of the atoms from an approximately nonpolar into a highly dipolar quantum state. The resultant electric dipole-dipole forces are probed using a device akin to a field ion microscope. Ion imaging and pair-correlation analysis reveal the kinetics of the interacting atoms. Dumbbell-shaped pair-correlation images demonstrate the anisotropy of the binary dipolar force. The dipolar C_{3} coefficient, derived from the time dependence of the images, agrees with the value calculated from the permanent electric-dipole moment of the atoms. The results indicate many-body dynamics akin to disorder-induced heating in strongly coupled particle systems. PMID:27284655
Properties of the superconductor in accelerator dipole magnets
NASA Astrophysics Data System (ADS)
Teravest, Derk
Several aspects of the application of superconductors to high field dipole magnets for particle accelerators are discussed. The attention is focused on the 10 tesla (1 m model) magnet that is envisaged for the future Large Hadron Collider (LHC) accelerator. The basic motivation behind the study is the intention of employing superconductors to their utmost performance. An overview of practical supercomputers, their applications and their impact on high field dipole magnets used for particle accelerators, is presented. The LHC reference design for the dipole magnets is outlined. Several models were used to study the influence of a number of factors in the shape and in particular, the deviation from the shape that is due to the flux flow state. For the investigated extrinsic and intrinsic factors, a classification can be made with respect to the effect on the shape of the characteristic of a multifilamentary wire. The optimization of the coil structure for high field dipole magnets, with respect to the field quality is described. An analytical model for solid and hollow filaments, to calculate the effect of filament magnetization in the quality of the dipole field, is presented.
Electric dipole moments of charged leptons with sterile fermions
NASA Astrophysics Data System (ADS)
Abada, Asmaa; Toma, Takashi
2016-02-01
We address the impact of sterile fermions on charged lepton electric dipole moments. Any experimental signal of these observables calls for scenarios of physics beyond the Standard Model providing new sources of CP violation. In this work, we consider a minimal extension of the Standard Model via the addition of sterile fermions which mix with active neutrinos and we derive the corresponding analytical expressions for the electric dipole moments of charged leptons at two-loop order. Our study reveals that, in order to have a non-vanishing contribution in this framework, the minimal extension necessitates the addition of at least 2 sterile fermion states to the Standard Model field content. Our conclusion is that sterile neutrinos can give significant contributions to the charged lepton electric dipole moments, some of them lying within present and future experimental sensitivity if the masses of the non-degenerate sterile states are both above the electroweak scale. The Majorana nature of neutrinos is also important in order to allow for significative contributions to the charged lepton electric dipole moments. In our analysis we impose all available experimental and observational constraints on sterile neutrinos and we further discuss the prospect of probing this scenario at low and high energy experiments.
Screening of nucleon electric dipole moments in nuclei
NASA Astrophysics Data System (ADS)
Inoue, Satoru; Gudkov, Vladimir; Schindler, Matthias R.; Song, Young-Ho
2016-05-01
A partial screening of nucleon electric dipole moments (EDMs) in nuclear systems, which is related to the Schiff mechanism known for neutral atomic systems, is discussed. It is shown that the direct contribution from the neutron EDM to the deuteron EDM is partially screened by about 1% in a zero-range approximation calculation.
Review of Electric Dipole Moments of Fundamental Particles
Semertzidis, Yannis K.
2009-08-04
Electric dipole moments (EDM) experiments are in the research frontier of CP-violation beyond the standard model (SM). EDM experiments set the current limits on CP-violation beyond the SM and are most likely to be the first ones to discover if nature has indeed chosen that path.
Enhancement of the electron electric dipole moment in gadolinium garnets
Mukhamedjanov, T.N.; Dzuba, V.A.; Sushkov, O.P.
2003-10-01
Effects caused by the electron electric dipole moment (EDM) in gadolinium garnets are considered. Experimental studies of these effects could improve the current upper limit on the electron EDM by several orders of magnitude. We suggest a consistent theoretical model and perform calculations of observable effects in gadolinium gallium garnet and gadolinium iron garnet. Our calculation accounts for both direct and exchange diagrams.
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.
Helical Dipole Magnets for Polarized Protons in RHIC
NASA Astrophysics Data System (ADS)
Syphers, M.; Courant, E.; Fischer, W.; Luccio, A.; Mariam, F.; Peggs, S.; Pilat, F.; Roser, T.; Tepikian, S.; Tsoupas, N.; Willen, E.; Katayama, T.; Hatanaka, K.; Kawaguchi, T.; Okamura, M.; Tominaka, T.; Wu, H.; Ptitsin, V.; Shatunov, Y.
1997-05-01
The Brookhaven Relativistic Heavy Ion Collider (RHIC) will be able to support experiments using polarized proton beams. Siberian Snakes are used to maintain polarization in this high energy superconducting collider. To make efficient use of available space while taking advantage of high field superconducting magnets, 4 Tesla helical dipole magnets will be used. These magnets generate a central dipole field in which the field direction rotates through 360^circ about the longitudinal axis over the length of the device. An arrangement of four such magnets can produce the desired change in the spin direction while keeping the proton orbit outside of the ``Snake'' unaltered. Similar magnet arrangements will be used to produce longitudinal polarization at the two major interaction points in RHIC. The basic requirements and layout of these magnets are described, as well as tolerances on field quality and integrated field strengths. First results of tests of prototype helical magnets will be discussed.
AC loss measurement of superconducting dipole magnets by the calorimetric method
Morita, Y.; Hara, K.; Higashi, N.; Kabe, A.
1996-12-31
AC losses of superconducting dipole magnets were measured by the calorimetric method. The magnets were model dipole magnets designed for the SSC. These were fabricated at KEK with 50-mm aperture and 1.3-m overall length. The magnet was set in a helium cryostat and cooled down to 1.8 K with 130 L of pressurized superfluid helium. Heat dissipated by the magnet during ramp cycles was measured by temperature rise of the superfluid helium. Heat leakage into the helium cryostat was 1.6 W and was subtracted from the measured heat to obtain AC loss of the magnet. An electrical measurement was carried out for calibration. Results of the two methods agreed within the experimental accuracy. The authors present the helium cryostat and measurement system in detail, and discuss the results of AC loss measurement.
An alternate method for designing dipole magnet ends
Pope, W.L.; Green, M.A.; Peters, C.; Caspi, S.; Taylor, C.E.
1988-08-01
Small bore superconducting dipole magnets, such as those for the SSC, often have problems in the ends. These problems can often be alleviated by spreading out the end windings so that the conductor sees less deformation. This paper presents a new procedure for designing dipole magnet ends which can be applied to magnets with either cylindrical or conical bulged ends to have integrated field multipoles which meet the constraints imposed by the SSC lattice. The method described here permits one to couple existing multiparameter optimization routines (i.e., MINUIT with suitable independent parameter constraints) with a computer code DIPEND, which describes the multiples, so that one can meet any reasonable objective (i.e., minimizing integrated sextupole and decapole). This paper will describe how the computer method was used to analyze the bulged conical ends for an SSC dipole. 6 refs, 6 figs, 2 tabs.
Longitudinal Gradient Dipole Magnet Prototype for APS at ANL
Kashikhin, V. S.; Borland, M.; Chlachidze, G.; Decker, G.; Dejus, R.; DiMarco, J.; Doose, C. L.; Gardner, T. J.; Harding, D. J.; Jaski, M. S.; et al
2016-01-26
We planned an upgrade of the Advanced Photon Source at Argonne National Laboratory (ANL). The main goal of the upgrade is to improve the storage ring performance based on more advanced optics. One of the key magnet system elements is bending dipole magnets having a field strength change along the electron beam path. Moreover, a prototype of one such longitudinal gradient dipole magnet has been designed, built, and measured in a collaborative effort of ANL and Fermilab. Our paper discusses various magnetic design options, the selected magnet design, and the fabrication technology. The prototype magnet has been measured by rotationalmore » coils, a stretched wire, and a Hall probe. Measurement results are discussed and compared with simulations.« less
Electromagnetic braking revisited with a magnetic point dipole model
NASA Astrophysics Data System (ADS)
Land, Sara; McGuire, Patrick; Bumb, Nikhil; Mann, Brian P.; Yellen, Benjamin B.
2016-04-01
A theoretical model is developed to predict the trajectory of magnetized spheres falling through a copper pipe. The derive magnetic point dipole model agrees well with the experimental trajectories for NdFeB spherical magnets of varying diameter, which are embedded inside 3D printed shells with fixed outer dimensions. This demonstration of electrodynamic phenomena and Lenz's law serves as a good laboratory exercise for physics, electromagnetics, and dynamics classes at the undergraduate level.
New Experiment to Measure the Electron Electric Dipole Moment
NASA Technical Reports Server (NTRS)
Kittle, Melanie
2003-01-01
An electron can possess an electric dipole moment (edm) only if time reversal symmetry (T) is violated. No edm of any particle has yet been discovered. CP-violation, equivalent to T-violation by the CPT theorem, does occur in Kaon decays and can be accounted for by the standard model. However, this mechanism leads to an electron edm d(sub e) of the order of 10(exp -38) e cm, whereas the current experimental bound on d(sub e) is about 10(exp -27) e cm. However, well-motivated extensions of the standard model such as supersymmetric theories do predict that de could be as large as the current bound. In addition, CP violation in the early universe is required to explain the preponderance of matter over anti-matter, but the exact mechanism of this CP violation is unclear. For these reasons, we are undertaking a new experimental program to determine de to an improved accuracy of 10(exp -29) e cm. Our experiment will use laser-cooled, trapped Cesium atoms to measure the atomic edm d(sub Cs) that occurs if d(sub e) is not zero. In order to do this, we will measure the energy splitting between the atoms spin states in parallel electric and magnetic fields. The signature of an edm would be a linear dependence of the splitting on the electric field E due to the interaction - d(sub Cs) dot E. Our measurement will be much more sensitive than previous measurements because atoms can be stored in the trap for tens of seconds, allowing for much narrower Zeeman resonance linewidths. Also, our method eliminates the most important systematic errors, proportional to atomic velocity, which have limited previous experiments. In this presentation, we will describe the design of our new apparatus, which is presently under construction. An important feature of our experimental apparatus is that magnetic field noise will be suppressed to a very low value of the order of 1 fT/(Hz)1/2. This requires careful attention to the Johnson noise currents in the chamber, which have not been important
Late kinetic decoupling of light magnetic dipole dark matter
NASA Astrophysics Data System (ADS)
Gondolo, Paolo; Kadota, Kenji
2016-06-01
We study the kinetic decoupling of light (lesssim 10 GeV) magnetic dipole dark matter (DM) . We find that present bounds from collider, direct DM searches, and structure formation allow magnetic dipole DM to remain in thermal equilibrium with the early universe plasma until as late as the electron-positron annihilation epoch. This late kinetic decoupling leads to a minimal mass for the earliest dark protohalos of thousands of solar masses, in contrast to the conventional weak scale DM scenario where they are of order 10‑6 solar masses.
Quantum-mechanical description of spin-1 particles with electric dipole moments
NASA Astrophysics Data System (ADS)
Silenko, Alexander J.
2013-04-01
The Proca-Corben-Schwinger equations for a spin-1 particle with an anomalous magnetic moment are added by a term describing an electric dipole moment, then they are reduced to a Hamiltonian form, and finally they are brought to the Foldy-Wouthuysen representation. Relativistic equations of motion are derived. The needed agreement between quantum-mechanical and classical relativistic equations of motion is proved. The scalar and tensor electric and magnetic polarizabilities of pointlike spin-1 particles (W bosons) are calculated for the first time.
NASA Astrophysics Data System (ADS)
Serebrov, A. P.; Kolomenskiy, E. A.; Pirozhkov, A. N.; Krasnoshchekova, I. A.; Vasiliev, A. V.; Polyushkin, A. O.; Lasakov, M. S.; Murashkin, A. N.; Solovey, V. A.; Fomin, A. K.; Shoka, I. V.; Zherebtsov, O. M.; Alexandrov, E. B.; Dmitriev, S. P.; Dovator, N. A.; Geltenbort, P.; Ivanov, S. N.; Zimmer, O.
2015-12-01
In this work, the double chamber magnetic resonance spectrometer of the Petersburg Nuclear Physics Institute (PNPI) designed to measure the neutron electric dipole moment (EDM) is briefly described. A method for long storage of polarized ultracold neutrons in a resonance space with a superposed electric field collinear to the leading magnetic field is used. The results of the measurements carried out on the ILL reactor (Grenoble, France) are interpreted as the upper limit of the value of neutron EDM |dn| < 5.5 × 10-26 e cm at the 90% confidence level.
Serebrov, A. P. Kolomenskiy, E. A.; Pirozhkov, A. N.; Krasnoshchekova, I. A.; Vasiliev, A. V.; Polyushkin, A. O.; Lasakov, M. S.; Murashkin, A. N.; Solovey, V. A.; Fomin, A. K.; Shoka, I. V.; Zherebtsov, O. M.; Alexandrov, E. B.; Dmitriev, S. P.; Dovator, N. A.; Geltenbort, P.; Ivanov, S. N.; Zimmer, O.
2015-12-15
In this work, the double chamber magnetic resonance spectrometer of the Petersburg Nuclear Physics Institute (PNPI) designed to measure the neutron electric dipole moment (EDM) is briefly described. A method for long storage of polarized ultracold neutrons in a resonance space with a superposed electric field collinear to the leading magnetic field is used. The results of the measurements carried out on the ILL reactor (Grenoble, France) are interpreted as the upper limit of the value of neutron EDM vertical bar d{sub n} vertical bar < 5.5 × 10{sup –26}e cm at the 90% confidence level.
SKEW QUADRUPOLES IN RHIC DIPOLE MAGNETS AT HIGH FIELDS.
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.
Skew quadrupole in RHIC dipole magnets at high fields
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.
Near-field induction heating of metallic nanoparticles due to infrared magnetic dipole contribution
NASA Astrophysics Data System (ADS)
Chapuis, Pierre-Olivier; Laroche, Marine; Volz, Sebastian; Greffet, Jean-Jacques
2008-03-01
We revisit the electromagnetic heat transfer between a metallic nanoparticle and a highly conductive metallic semi-infinite substrate, commonly studied using the electric dipole approximation. For infrared and microwave frequencies, we find that the magnetic polarizability of the particle is larger than the electric one. We also find that the local density of states in the near field is dominated by the magnetic contribution. As a consequence, the power absorbed by the particle in the near field is due to dissipation by fluctuating eddy currents. These results show that a number of near-field effects involving metallic particles should be affected by the fluctuating magnetic fields.
Lestrange, Patrick J.; Egidi, Franco; Li, Xiaosong
2015-12-21
The interaction between a quantum mechanical system and plane wave light is usually modeled within the electric dipole approximation. This assumes that the intensity of the incident field is constant over the length of the system and transition probabilities are described in terms of the electric dipole transition moment. For short wavelength spectroscopies, such as X-ray absorption, the electric dipole approximation often breaks down. Higher order multipoles are then included to describe transition probabilities. The square of the magnetic dipole and electric quadrupole are often included, but this results in an origin-dependent expression for the oscillator strength. The oscillator strength can be made origin-independent if all terms through the same order in the wave vector are retained. We will show the consequences and potential pitfalls of using either of these two expressions. It is shown that the origin-dependent expression may violate the Thomas-Reiche-Kuhn sum rule and the origin-independent expression can result in negative transition probabilities.
NASA Astrophysics Data System (ADS)
Lestrange, Patrick J.; Egidi, Franco; Li, Xiaosong
2015-12-01
The interaction between a quantum mechanical system and plane wave light is usually modeled within the electric dipole approximation. This assumes that the intensity of the incident field is constant over the length of the system and transition probabilities are described in terms of the electric dipole transition moment. For short wavelength spectroscopies, such as X-ray absorption, the electric dipole approximation often breaks down. Higher order multipoles are then included to describe transition probabilities. The square of the magnetic dipole and electric quadrupole are often included, but this results in an origin-dependent expression for the oscillator strength. The oscillator strength can be made origin-independent if all terms through the same order in the wave vector are retained. We will show the consequences and potential pitfalls of using either of these two expressions. It is shown that the origin-dependent expression may violate the Thomas-Reiche-Kuhn sum rule and the origin-independent expression can result in negative transition probabilities.
Lestrange, Patrick J; Egidi, Franco; Li, Xiaosong
2015-12-21
The interaction between a quantum mechanical system and plane wave light is usually modeled within the electric dipole approximation. This assumes that the intensity of the incident field is constant over the length of the system and transition probabilities are described in terms of the electric dipole transition moment. For short wavelength spectroscopies, such as X-ray absorption, the electric dipole approximation often breaks down. Higher order multipoles are then included to describe transition probabilities. The square of the magnetic dipole and electric quadrupole are often included, but this results in an origin-dependent expression for the oscillator strength. The oscillator strength can be made origin-independent if all terms through the same order in the wave vector are retained. We will show the consequences and potential pitfalls of using either of these two expressions. It is shown that the origin-dependent expression may violate the Thomas-Reiche-Kuhn sum rule and the origin-independent expression can result in negative transition probabilities. PMID:26696042
An update on passive correctors for the SSC dipole magnets
Green, M.A.
1991-05-01
The concept of correction of the magnetization sextupole became a topic of discussion as soon as it was realized that superconductor magnetization could have a serious effect on the SSC beam during injection. Several methods of correction were proposed. These included (1) correction with active bore tube windings like those on the HERA machine which correct out magnetization sextupole and the sextupole due to iron saturation, (2) correction with persistent sextupole windings mounted on the bore tube (3) correction using passive superconductor (4) correction using ferromagnetic material, and (5) correction using oriented magnetized materials. This report deals with the use of passive superconductor to correct the magnetization sextupole. Two basic methods are explored in this report: (1) One can correct the magnetization sextupole by changing the diameter of the superconductor filaments in one or more blocks of the SSC dipole. (2) One can correct the magnetization sextupole and decapole by mounting passive superconducting wires on the inside of the SSC dipole coil bore. In addition, an assessment of the contribution of each conductor in the dipole to the magnetization sextupole and decapole is shown. 38 refs, 25 figs., 15 tabs.
Dipole-exchange spin waves in magnetic nanomaterials
NASA Astrophysics Data System (ADS)
Nguyen, Thi Hoa
The aim of this thesis is to investigate the dipole-exchange spin waves in several low-dimensional ferromagnetic nanosystems. A microscopic theory is employed based on a Hamiltonian approach and a discrete lattice model. The Hamiltonian includes both the exchange and the magnetic dipole-dipole interactions, as well as the single-ion anisotropy and a Zeeman term for an externally applied magnetic field. Some of the advantages of this microscopic theory over the macroscopic methods are that it is convenient for describing the dynamical properties of samples where the magnetization may be spatially inhomogeneous, and it does not require the specification of phenomenological boundary conditions at the sample surfaces. The spin wave frequencies are obtained by employing a boson operator method with a diagonalization procedure. The spectral intensity, spin wave amplitudes and effective pinning are also studied within a Green function theory. The spin wave properties are first studied for ultrathin ferromagnetic films with simple cubic, body-centered cubic and face-centered cubic lattice structures. Results are deduced for the spin wave frequencies as a function of the in-plane wave vector, the magnetic field applied either parallel or perpendicular to the film surfaces, and the material parameters. The spin wave properties are shown to depend sensitively on the lattice structures in certain wave-vector regimes. Next we carry out spin wave calculations for individual (non-interacting) ferromagnetic stripes or wires. The numerical results are compared with the macroscopic theories and with the experimental data, where available. Then we examine the role of the long-range dipole-dipole interactions between stripes on the spin waves for two different types of stripe arrays. The coupling is found to depend on the array geometry and the direction of the applied field. Comparison of our results with experimental data (e.g., for Permalloy) shows a good agreement, confirming the
The field of the vertical electric dipole immersed in the heterogeneous half-space
NASA Astrophysics Data System (ADS)
Barsukov, P. O.; Fainberg, E. B.
2014-07-01
The field of the vertical electric dipole (VED) immersed in the heterogeneous conductive halfspace (sea) is analyzed in time domain. In the near field of the source, the amplitudes of the electric and magnetic components of the field are proportional to power 3/2 and power 5/2 of the conductivity of the medium, respectively. After termination of the transmitter pulse, all the VED components decay with time as ˜1/ t 5/2. The possibility of applying the VED field for estimating the electrical properties of the offshore geological sections is demonstrated.
Neutron electric dipole moment and possibilities of increasing accuracy of experiments
NASA Astrophysics Data System (ADS)
Serebrov, A. P.; Kolomenskiy, E. A.; Pirozhkov, A. N.; Krasnoshchekova, I. A.; Vasiliev, A. V.; Polyushkin, A. O.; Lasakov, M. S.; Murashkin, A. N.; Solovey, V. A.; Fomin, A. K.; Shoka, I. V.; Zherebtsov, O. M.; Aleksandrov, E. B.; Dmitriev, S. P.; Dovator, N. A.; Geltenbort, P.; Ivanov, S. N.; Zimmer, O.
2016-01-01
The paper reports the results of an experiment on searching for the neutron electric dipole moment (EDM), performed on the ILL reactor (Grenoble, France). The double-chamber magnetic resonance spectrometer (Petersburg Nuclear Physics Institute (PNPI)) with prolonged holding of ultra cold neutrons has been used. Sources of possible systematic errors are analyzed, and their influence on the measurement results is estimated. The ways and prospects of increasing accuracy of the experiment are discussed.
Intrinsic nonlinear effects of dipole magnets in small rings
NASA Astrophysics Data System (ADS)
Xu, H. S.; Huang, W. H.; Tang, C. X.; Lee, S. Y.
2016-06-01
We find that dynamic aperture depends significantly on the bending radii of dipole magnets when designing a small storage ring for Tsinghua Thomson scattering X-ray source (TTX) mainly because of the nonlinearity of the dipole field. In this paper, we present systematic studies on the intrinsic-geometric nonlinearity of dipole magnets. The Hamiltonian approach is used to determine the expressions of the geometric nonlinear potential and the corresponding third-order resonance strengths. Simulations are conducted to study these resonances. Our analysis results agree well with the tracking results at the third-order resonances 3 νx=ℓ and νx±2 νz=ℓ , where ℓ 's are the integer multiple of the number of superperiods.
Quantum electrodynamical corrections to a magnetic dipole in general relativity
NASA Astrophysics Data System (ADS)
Pétri, J.
2016-03-01
Magnetized neutron stars are privileged places where strong electromagnetic fields as high as BQ = 4.4 × 109 T exist, giving rise to non-linear corrections to Maxwell equations described by quantum electrodynamics (QED). These corrections need to be included to the general relativistic (GR) description of a magnetic dipole supposed to be anchored in the neutron star. In this paper, these QED and GR perturbations to the standard flat space-time dipole are calculated to the lowest order in the fine structure constant αsf and to any order in the ratio Rs/R where R is the neutron star radius and Rs its Schwarzschild radius. Following our new 3+1 formalism developed in a previous work, we compute the multipolar non-linear corrections to this dipole and demonstrate the presence of a small dipolar ℓ = 1 and hexapolar ℓ = 3 component.
Splitting of magnetic dipole modes in anisotropic TiO2 micro-spheres
Khromova, Irina; Kuzel, Petr; Brener, Igal; Reno, John L.; Chung Seu, U-Chan; Elissalde, Catherine; Maglione, Mario; Mounaix, Patrick; Mitrofanov, Oleg
2016-06-27
Monocrystalline titanium dioxide (TiO2) micro-spheres support two orthogonal magnetic dipole modes at terahertz (THz) frequencies due to strong dielectric anisotropy. For the first time, we experimentally detected the splitting of the first Mie mode in spheres of radii inline imagem through near-field time-domain THz spectroscopy. By fitting the Fano lineshape model to the experimentally obtained spectra of the electric field detected by the sub-wavelength aperture probe, we found that the magnetic dipole resonances in TiO2 spheres have narrow linewidths of only tens of gigahertz. Lastly, anisotropic TiO2 micro-resonators can be used to enhance the interplay of magnetic and electric dipolemore » resonances in the emerging THz all-dielectric metamaterial technology.« less
Limit on the electron electric dipole moment in gadolinium-iron garnet.
Heidenreich, B J; Elliott, O T; Charney, N D; Virgien, K A; Bridges, A W; McKeon, M A; Peck, S K; Krause, D; Gordon, J E; Hunter, L R; Lamoreaux, S K
2005-12-16
A new method for the detection of the electron electric dipole moment (EDM) using a solid is described. The method involves the measurement of a voltage induced across the solid by the alignment of the sample's magnetic dipoles in an applied magnetic field, H. A first application of the method to GdIG has resulted in a limit on the electron EDM of 5 x 10(-24)e cm, which is a factor of 40 below the limit obtained from the only previous solid-state EDM experiment. The result is limited by the imperfect discrimination of an unexpectedly large voltage that is even upon the reversal of the sample magnetization. PMID:16384457
Electric dipole moment in the split supersymmetry models
Chang, Darwin; Chang, W.-F.; Keung, W.-Y.
2005-04-01
We study an important contribution to the electric dipole moment (EDM) of the electron (or quarks) at the two-loop level due to the W-EDM in the recently proposed scenario of split supersymmetry. This contribution is independent of the Higgs mass, and it can enhance the previous estimation of the electron (neutron) EDM by 20-50% (40-90%). Our formula is new in its analytical form.
Self-generated magnetic dipoles in weakly magnetized beam-plasma system.
Jia, Qing; Mima, Kunioki; Cai, Hong-bo; Taguchi, Toshihiro; Nagatomo, Hideo; He, X T
2015-02-01
A self-generation mechanism of magnetic dipoles and the anomalous energy dissipation of fast electrons in a magnetized beam-plasma system are presented. Based on two-dimensional particle-in-cell simulations, it is found that the magnetic dipoles are self-organized and play important roles in the beam electron energy dissipation. These dipoles drift slowly in the direction of the return flow with a quasisteady velocity, which depends upon the magnetic amplitude of the dipole and the imposed external magnetic field. This dipole formation provides a mechanism for the anomalous energy dissipation of a relativistic electron beam, which would play an important role in collisionless shock and ion shock acceleration. PMID:25768618
The permanent and induced magnetic dipole moment of the moon
NASA Technical Reports Server (NTRS)
Russell, C. T.; Coleman, P. J., Jr.; Lichtenstein, B. R.; Schubert, G.
1974-01-01
Magnetic field observations with the Apollo 15 subsatellite have been used to deduce the components of both the permanent and induced lunar dipole moments in the orbital plane. The present permanent lunar magnetic dipole moment in the orbital plane is less than 1.3 times ten to the eighteenth power gauss-cu cm. Any uniformly magnetized near surface layer is therefore constrained to have a thickness-magnetization product less than 2.5 emu-cm per g. The induced moment opposes the external field, implying the existence of a substantial lunar ionosphere with a permeability between 0.63 and 0.85. Combining this with recent measures of the ratio of the relative field strength at the ALSEP and Explorer 35 magnetometers indicates that the global lunar permeability relative to the plasma in the geomagnetic tail lobes is between 1.008 and 1.03.
A dipole probe for electric field measurements in the LVPD
NASA Astrophysics Data System (ADS)
Srivastava, P. K.; Awasthi, L. M.; Ravi, G.; Kumar, Sunil; Mattoo, S. K.
2016-01-01
This paper describes the design, construction, and calibration of an electric dipole probe and demonstrates its capability by presenting results on the measurement of electric field excited by a ring electrode in the Large Volume Plasma Device (LVPD). It measures the electric field in vacuum and plasma conditions in a frequency range lying between 1-10 \\text{MHz} . The results show that it measures electric field ≥slant 2 mV cm-1 for frequency ≤slant 10 \\text{MHz} . The developed dipole probe works on the principle of amplitude modulation. The probe signal is transmitted through a carrier of 418 MHz, a much higher frequency than the available sources of noise present in the surrounding environment. The amplitude modulation concept of signal transmission is used to make the measurement; it is qualitatively better and less corrupted as it is not affected by the errors introduced by ac pickups. The probe is capable of measuring a variety of electric fields, namely (1) space charge field, (2) time varying field, (3) inductive field and (4) a mixed field containing both space charge and inductive fields. This makes it a useful tool for measuring electric fields in laboratory plasma devices.
A rotating solar magnetic "dipole' observed from 1926 to 1968.
NASA Technical Reports Server (NTRS)
Wilcox, J. M.; Gonzalez, W.
1971-01-01
A recurring pattern with a period of 26 7/8 days observed in the polar geomagnetic field during the interval from 1926 to 1941 appears to persist in the interplanetary magnetic field polarity observed with spacecraft during the interval from 1963 to 1968. This observation suggests the existence of a rotating solar magnetic ?dipole' with a period of 26 7/8 plus or minus 0.003 days.
Electric Dipole Moments of Nanosolvated Acid Molecules in Water Clusters
NASA Astrophysics Data System (ADS)
Guggemos, Nicholas; Slavíček, Petr; Kresin, Vitaly V.
2015-01-01
The electric dipole moments of (H2O)nDCl (n =3 - 9 ) clusters have been measured by the beam-deflection method. Reflecting the (dynamical) charge distribution within the system, the dipole moment contributes information about the microscopic structure of nanoscale solvation. The addition of a DCl molecule to a water cluster results in a strongly enhanced susceptibility. There is evidence for a noticeable rise in the dipole moment occurring at n ≈5 - 6 . This size is consistent with predictions for the onset of ionic dissociation. Additionally, a molecular-dynamics model suggests that even with a nominally bound impurity an enhanced dipole moment can arise due to the thermal and zero-point motion of the proton and the water molecules. The experimental measurements and the calculations draw attention to the importance of fluctuations in defining the polarity of water-based nanoclusters and generally to the essential role played by motional effects in determining the response of fluxional nanoscale systems under realistic conditions.
Constraining the neutrino magnetic dipole moment from white dwarf pulsations
NASA Astrophysics Data System (ADS)
Córsico, A. H.; Althaus, L. G.; Miller Bertolami, M. M.; Kepler, S. O.; García-Berro, E.
2014-08-01
Pulsating white dwarf stars can be used as astrophysical laboratories to constrain the properties of weakly interacting particles. Comparing the cooling rates of these stars with the expected values from theoretical models allows us to search for additional sources of cooling due to the emission of axions, neutralinos, or neutrinos with magnetic dipole moment. In this work, we derive an upper bound to the neutrino magnetic dipole moment (μν) using an estimate of the rate of period change of the pulsating DB white dwarf star PG 1351+489. We employ state-of-the-art evolutionary and pulsational codes which allow us to perform a detailed asteroseismological period fit based on fully DB white dwarf evolutionary sequences. Plasmon neutrino emission is the dominant cooling mechanism for this class of hot pulsating white dwarfs, and so it is the main contributor to the rate of change of period with time (Pi dot) for the DBV class. Thus, the inclusion of an anomalous neutrino emission through a non-vanishing magnetic dipole moment in these sequences notably influences the evolutionary timescales, and also the expected pulsational properties of the DBV stars. By comparing the theoretical Pi dot value with the rate of change of period with time of PG 1351+489, we assess the possible existence of additional cooling by neutrinos with magnetic dipole moment. Our models suggest the existence of some additional cooling in this pulsating DB white dwarf, consistent with a non-zero magnetic dipole moment with an upper limit of μν lesssim 10-11 μB. This bound is somewhat less restrictive than, but still compatible with, other limits inferred from the white dwarf luminosity function or from the color-magnitude diagram of the Globular cluster M5. Further improvements of the measurement of the rate of period change of the dominant pulsation mode of PG 1351+489 will be necessary to confirm our bound.
Constraining the neutrino magnetic dipole moment from white dwarf pulsations
Córsico, A.H.; Althaus, L.G.; García-Berro, E. E-mail: althaus@fcaglp.unlp.edu.ar E-mail: kepler@if.ufrgs.br
2014-08-01
Pulsating white dwarf stars can be used as astrophysical laboratories to constrain the properties of weakly interacting particles. Comparing the cooling rates of these stars with the expected values from theoretical models allows us to search for additional sources of cooling due to the emission of axions, neutralinos, or neutrinos with magnetic dipole moment. In this work, we derive an upper bound to the neutrino magnetic dipole moment (μ{sub ν}) using an estimate of the rate of period change of the pulsating DB white dwarf star PG 1351+489. We employ state-of-the-art evolutionary and pulsational codes which allow us to perform a detailed asteroseismological period fit based on fully DB white dwarf evolutionary sequences. Plasmon neutrino emission is the dominant cooling mechanism for this class of hot pulsating white dwarfs, and so it is the main contributor to the rate of change of period with time (Pidot) for the DBV class. Thus, the inclusion of an anomalous neutrino emission through a non-vanishing magnetic dipole moment in these sequences notably influences the evolutionary timescales, and also the expected pulsational properties of the DBV stars. By comparing the theoretical Pidot value with the rate of change of period with time of PG 1351+489, we assess the possible existence of additional cooling by neutrinos with magnetic dipole moment. Our models suggest the existence of some additional cooling in this pulsating DB white dwarf, consistent with a non-zero magnetic dipole moment with an upper limit of μ{sub ν} ∼< 10{sup -11} μ{sub B}. This bound is somewhat less restrictive than, but still compatible with, other limits inferred from the white dwarf luminosity function or from the color-magnitude diagram of the Globular cluster M5. Further improvements of the measurement of the rate of period change of the dominant pulsation mode of PG 1351+489 will be necessary to confirm our bound.
NASA Astrophysics Data System (ADS)
Gang, Yin; Yingtang, Zhang; Hongbo, Fan; Zhining, Li; Guoquan, Ren
2016-05-01
We have developed a method for automatic detection, localization and classification (DLC) of multiple dipole sources using magnetic gradient tensor data. First, we define modified tilt angles to estimate the approximate horizontal locations of the multiple dipole-like magnetic sources simultaneously and detect the number of magnetic sources using a fixed threshold. Secondly, based on the isotropy of the normalized source strength (NSS) response of a dipole, we obtain accurate horizontal locations of the dipoles. Then the vertical locations are calculated using magnitude magnetic transforms of magnetic gradient tensor data. Finally, we invert for the magnetic moments of the sources using the measured magnetic gradient tensor data and forward model. Synthetic and field data sets demonstrate effectiveness and practicality of the proposed method.
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.
Refrigeration options for the Advanced Light Source Superbend Dipole Magnets
Green, M.A.; Hoyer, E.H.; Schlueter, R.D.; Taylor, C.E.; Zbasnik, J.; Wang, S.T.
1999-07-09
The 1.9 GeV Advance Light Source (ALS) at the Lawrence Berkeley National Laboratory (LBNL) produces photons with a critical energy of about 3.1 kev at each of its thirty-six 1.3 T gradient bending magnets. It is proposed that at three locations around the ring the conventional gradient bending magnets be replaced with superconducting bending magnets with a maximum field of 5.6 T. At the point where the photons are extracted, their critical energy will be about 12 keV. In the beam lines where the SuperBend superconducting magnets are installed, the X ray brightness at 20 keV will be increased over two orders of magnitude. This report describes three different refrigeration options for cooling the three SuperBend dipoles. The cooling options include: (1) liquid helium and liquid nitrogen cryogen cooling using stored liquids, (2) a central helium refrigerator (capacity 70 to 100 W) cooling all of the SuperBend magnets, (3) a Gifford McMahon (GM) cryocooler on each of the dipoles. This paper describes the technical and economic reasons for selecting a small GM cryocooler as the method for cooling the SuperBend dipoles on the LBNL Advanced Light Source.
Magnetic field properties of Fermilab Energy-Saver dipoles
Hanft, R.; Brown, B.C.; Cooper, W.E.; Gross, D.A.; Michelotti, L.; Schmidt, E.E.; Turkot, F.
1983-03-01
At Fermilab we have operated a production line for the fabrication of 901 21 foot long superconducting dipoles for use in the Energy Saver/Doubler. At any one time 772 of these dipoles are installed in the accelerator and 62 in beamlines; the remainder are spares. Magnetic field data are now available for most of these dipoles; in this paper we present some of these data which show that we have been able to maintain the necessary consistency in field quality throughout the production process. Specifically we report harmonic field coefficients, showing that the mechanical design permits substantial reduction of the magnitudes of the normal and skew quadrupole harmonic coefficients; field shape profiles; integral field data; and field angle data.
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
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.
A radiation hard dipole magnet coils using aluminum clad copper conductors
Leonhardt, W.J.
1989-01-01
A C-type septum dipole magnet is located 600 mm downstream of the primary target in an external beam line of the AGS. Conventional use of fiber glass/epoxy electrical insulation for the magnet coils results in their failure after a relatively short running period, therefore a radiation hard insulation system is required. This is accomplished by replacing the existing copper conductor with a copper conductor having a thin aluminum skin which is anodized to provide the electrical insulation. Since the copper supports a current density of 59 A/mm/sup 2/, no reduction in cross sectional area can be tolerated. Design considerations, manufacturing techniques, and operating experience of a prototype dipole is presented. 3 refs., 4 figs.
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.
Development of a xenon polarizer for magnetometry in neutron electric dipole moment experiments
NASA Astrophysics Data System (ADS)
Dawson, Troy
Next generation electric dipole moment experiments require precise knowledge of the local magnetic fields in the experimental volume. Hyperpolarized xenon-129 has been proposed as a comagnetometer gas to be used in the neutron electric dipole moment experiment planned for TRIUMF. A flow through xenon polarizer was constructed and tested, and the hyperpolarized Xe-129 produced was transported to and characterized using a new AFP-NMR spectrometer. The polarization measured in the external AFP-NMR spectrometer was (12 +/- 4)%. The longitudinal spin relaxation time T1 was found to be (77 +/- 24) s in the experimental NMR volume, limited by leaks and field inhomogeneity. This represents good progress towards the eventual system for nEDM experiments where polarizations greater than 50% and T1, T2 relaxation times greater than 1000 s are expected.
A new experimental limit on the electric dipole moment of the electron
Carlberg, C.; Gould, H. ); Abdullah, K.; Commins, E.D.; Ross, S.B. California Univ., Berkeley, CA . Dept. of Physics)
1990-12-01
We describe a search for the electric dipole moment d{sub e} of the electron, carried out with {sup 205}Tl atoms in the ground state. The experiment makes use of the separated-oscillating-field magnetic-resonance method, laser state selection, fluorescence detection, and two counter-propagating atomic beams. Very careful attention is paid to systematic effects. The result for the atomic electric dipole moment is d{sub a} = (1.6 {plus minus} 5.0) {times} 10{sup {minus}24} e cm. If we assume the theoretical ratio d{sub a}/d{sub e} = {minus}600, this yields d{sub e} = ({minus}2.7 {plus minus} 8.3) {times} 10{sup {minus}27} e cm. 17 refs., 7 figs., 1 tab.
Magnetic dipole moment determination by near-field analysis
NASA Technical Reports Server (NTRS)
Eichhorn, W. L.
1972-01-01
A method for determining the magnetic moment of a spacecraft from magnetic field data taken in a limited region of space close to the spacecraft. The spacecraft's magnetic field equations are derived from first principles. With measurements of this field restricted to certain points in space, the near-field equations for the spacecraft are derived. These equations are solved for the dipole moment by a least squares procedure. A method by which one can estimate the magnitude of the error in the calculations is also presented. This technique was thoroughly tested on a computer. The test program is described and evaluated, and partial results are presented.
Full length SSC R and D dipole magnet test results
Strait, J.; Bleadon, M.; Brown, B.C.; Hanft, R.; Kuchnir, M.; Lamm, M.; Mantsch, P.; Mazur, P.O.; Orris, D.; Peoples, J.
1989-03-01
Four full scale SSC development dipole magnets have been tested for mechanical and quench behavior. Two are of a design similar to previous magnets but contain a number of improvements, including more uniform coil size, higher pre-stress and a redesigned inner-outer coil splice. One exceeds the SSC operating current on the second quench but the other appears to be limited by damaged superconductor to a lower current. The other two magnets are of alternate designs. One trains erratically and fails to reach a plateau and the other reaches plateau after four quenches. 12 refs., 4 figs.
Construction techniques for short iron-free dipole magnets
Harvey, A.R.
1983-11-08
A method was developed for economically fabricating short, wire-wound, steering magnets with maximum length, cosine-distributed, axial elements. This method utilizes multifunctional tooling to precisely flat-wind two-layer dipole halves that are subsequently reformed and encapsulated into semicylindrical form with confinement of the end turns into thin, half discs normal to the magnet axis. This paper addresses the magnet fabrication in detail, highlighting the inherent quality control features of the tooling, overall construction costs, and contemplated manufacturing enhancements.
Local spin torque induced by electron electric dipole moment in the YbF molecule
Fukuda, Masahiro; Senami, Masato; Ogiso, Yoji; Tachibana, Akitomo
2014-10-06
In this study, we show the modification of the equation of motion of the electronic spin, which is derived by the quantum electron spin vorticity principle, by the effect of the electron electric dipole moment (EDM). To investigate the new contribution to spin torque by EDM, using first principle calculations, we visualize distributions of the local spin angular momentum density and local spin torque density of the YbF molecule on which the static electric field and magnetic field are applied at t = 0.
Local spin torque induced by electron electric dipole moment in the Ybf molecule
NASA Astrophysics Data System (ADS)
Fukuda, Masahiro; Senami, Masato; Ogiso, Yoji; Tachibana, Akitomo
2014-10-01
In this study, we show the modification of the equation of motion of the electronic spin, which is derived by the quantum electron spin vorticity principle, by the effect of the electron electric dipole moment (EDM). To investigate the new contribution to spin torque by EDM, using first principle calculations, we visualize distributions of the local spin angular momentum density and local spin torque density of the YbF molecule on which the static electric field and magnetic field are applied at t = 0.
Study By Spin Tracking of A Storage Ring For Deuteron Electric Dipole Moment
Lin, F.; Malitsky, N. D.; Luccio, A. U.; Morse, W. M.; Semertzidis, Y. K.; Onderwater, C. J. G.; Orlov, Y. F.
2009-08-04
Spin tracking of polarized deuterons for a proposed experiment to measure a possible Electric Dipole Moment (EDM) of the deuteron was done by using the codes UAL and SPINK. In the experiment the direction of spin polarization will be frozen using crossed electric and magnetic fields. Systematics, in particular the effects of non-linearities of the lattice on a beam with finite emittance and energy spread, have been extensively simulated and the effect of sextuple corrections to increase the spin coherence time has been studied.
NASA Astrophysics Data System (ADS)
Ungier, W.
2014-05-01
Theoretical description of Rashba effects in three-dimensional electron gas at electric-dipole spin resonance conditions is presented in the frame of conductivity tensor formalism. The details due to anisotropy of the effective mass tensor, as well as the Lande factor, are considered. The absorbed power is calculated for arbitrary orientation of the sample with respect to external fields: constant magnetic field and rf electric field. The differences between resonance signals in two- and three-dimensional electron gas are pointed out.
Candidate molecular ions for an electron electric dipole moment experiment
Meyer, Edmund R.; Bohn, John L.; Deskevich, Michael P.
2006-06-15
This paper is a theoretical work in support of a newly proposed experiment [R. Stutz and E. Cornell, Bull. Am. Soc. Phys. 89, 76 (2004)] that promises greater sensitivity to measurements of the electron's electric dipole moment (EDM) based on the trapping of molecular ions. Such an experiment requires the choice of a suitable molecule that is both experimentally feasible and possesses an expectation of a reasonable EDM signal. We find that the molecular ions PtH{sup +} and HfH{sup +} are both suitable candidates in their low-lying {sup 3}{delta} states. In particular, we anticipate that the effective electric fields generated inside these molecules are approximately 73 and -17 GV/cm, respectively. As a byproduct of this discussion, we also explain how to make estimates of the size of the effective electric field acting in a molecule, using commercially available nonrelativistic molecular structure software.
Dipole corrector magnets for the LBNE beam line
Yu, M.; Velev, G.; Harding, D.; /Fermilab
2011-03-01
The conceptual design of a new dipole corrector magnet has been thoroughly studied. The planned Long-Baseline Neutrino Experiment (LBNE) beam line will require correctors capable of greater range and linearity than existing correctors, so a new design is proposed based on the horizontal trim dipole correctors built for the Main Injector synchrotron at Fermilab. The gap, pole shape, length, and number of conductor turns remain the same. To allow operation over a wider range of excitations without overheating, the conductor size is increased, and to maintain better linearity, the back leg thickness is increased. The magnetic simulation was done using ANSYS to optimize the shape and the size of the yoke. The thermal performance was also modeled and analyzed.
Dynamics and thermodynamics of a pair of interacting magnetic dipoles
NASA Astrophysics Data System (ADS)
Schmidt, Heinz-Jürgen; Schröder, Christian; Hägele, Eva; Luban, Marshall
2015-05-01
We consider the dynamics and thermodynamics of a pair of magnetic dipoles interacting via their magnetic fields. We consider only the ‘spin’ degrees of freedom; the dipoles are fixed in space. With this restriction it is possible to provide the general solution of the equations of motion in analytical form. Thermodynamic quantities, such as the specific heat and the zero field susceptibility are calculated analytically or by combining low temperature asymptotic series and a complete high temperature expansion. The thermal expectation value of the autocorrelation function is determined for the low temperature regime and short times including terms linear in T. Furthermore, we have performed Monte Carlo simulations for the system under consideration and compared our analytical results with these.
Parity-violating electric-dipole transitions in helium
NASA Technical Reports Server (NTRS)
Hiller, J.; Sucher, J.; Bhatia, A. K.; Feinberg, G.
1980-01-01
The paper examines parity-violating electric-dipole transitions in He in order to gain insight into the reliability of approximate calculations which are carried out for transitions in many-electron atoms. The contributions of the nearest-lying states are computed with a variety of wave functions, including very simple product wave functions, Hartree-Fock functions and Hylleraas-type wave functions with up to 84 parameters. It is found that values of the matrix elements of the parity-violating interaction can differ considerably from the values obtained from the good wave functions, even when these simple wave functions give accurate values for the matrix elements in question
Reappraisal of the Electric Dipole Moment Enhancement Factor for Thallium
Nataraj, H. S.; Sahoo, B. K.; Das, B. P.; Mukherjee, D.
2011-05-20
The electric dipole moment (EDM) enhancement factor of atomic Tl is of considerable interest as it has been used in determining the most accurate limit on the electron EDM to date. However, its value varies from -179 to -1041 in different approximations. In view of the large uncertainties associated with many of these calculations, we perform an accurate calculation employing the relativistic coupled-cluster theory and obtain -466, which in combination with the most accurate measurement of Tl EDM [Phys. Rev. Lett. 88, 071805 (2002)] yields a new limit for the electron EDM: |d{sub e}|<2.0x10{sup -27}e cm.
T violation in radiative β decay and electric dipole moments
NASA Astrophysics Data System (ADS)
Dekens, W.; Vos, K. K.
2015-12-01
In radiative β decay, T violation can be studied through a spin-independent T-odd correlation. We consider contributions to this correlation by beyond the standard model (BSM) sources of T-violation, arising above the electroweak scale. At the same time such sources, parametrized by dimension-6 operators, can induce electric dipole moments (EDMs). As a consequence, the manifestations of the T-odd BSM physics in radiative β decay and EDMs are not independent. Here we exploit this connection to show that current EDM bounds already strongly constrain the spin-independent T-odd correlation in radiative β decay.
The permanent electric dipole moment of chromium monoxide
NASA Technical Reports Server (NTRS)
Steimle, Timothy C.; Nachman, David F.; Shirley, Jeffrey E.; Bauschlicher, Charles W.; Langhoff, Stephen R.
1989-01-01
The permanent electric dipole moments for the X 5Pi and B 5pi states of gas-phase CrO have been experimentally determined using the sub-Doppler optical technique of intermodulated fluorescence spectroscopy in conjunction with the Stark effect. The measured values are 3.88 + or - 0.13 and 4.1 + or - 1.8 D for the X and B states, respectively. The theoretical values determined for the X state using multireference CI iterative-natural-orbital and finite-field calculations are in excellent agreement with the experimental value.
Status and Prospects of Electric Dipole Moment Measurements
NASA Astrophysics Data System (ADS)
Cianciolo, Vince
2015-10-01
Precision electric dipole moment (EDM) measurements are extremely sensitive to non-Standard Model sources of charge/parity violation required for generation of the observed matter/anti-matter asymmetry in the universe. Many experiments in many systems are underway. In a half-hour talk it is difficult to do more than scratch the surface, but I will attempt to give a high-level overview on the various ongoing efforts. Research sponsored by the Office of Nuclear Physics, US Department of Energy.
Magnetic dipole sequences in {sup 83}Rb
Schwengner, R.; Schnare, H.; Wagner, A.; Doenau, F.; Rainovski, G.; Frauendorf, S.; Jungclaus, A.; Hausmann, M.; Lieb, K. P.; Yordanov, O.; Napoli, D. R.; De Angelis, G.; Axiotis, M.; Marginean, N.; Brandolini, F.; Alvarez, C. Rossi
2009-10-15
High-spin states in {sup 83}Rb were populated in the reaction {sup 11}B+{sup 76}Ge at beam energies of 45 and 50 MeV. {gamma} rays were detected with the spectrometer GASP. The level scheme of {sup 83}Rb was extended up to 13.9 MeV. Mean lifetimes of 23 levels were determined using the Doppler-shift-attenuation method. Among the bands newly established is a sequence comprising intense M1 transitions and crossover E2 transitions. This sequence turns out to be irregular and thus shows that magnetic rotation as observed in the neighboring odd-odd isotopes is not realized in this odd-even nuclide. Excited states in {sup 83}Rb were interpreted in terms of the shell model using the model space {pi}(0f{sub 5/2},1p{sub 3/2},1p{sub 1/2},0g{sub 9/2}) {nu}(1p{sub 1/2},0g{sub 9/2}). The configurations predicted for the negative-parity M1 sequence reproduce the M1 transition strengths fairly well.
Magnetic dipole excitations of the 163Dy nucleus
NASA Astrophysics Data System (ADS)
Zenginerler, Zemine; Tabar, Emre; Yakut, Hakan; Kuliev, Ali Akbar; Guliyev, Ekber
2014-03-01
In this study some properties of the magnetic dipole excitations of the deformed odd mass 163Dy nucleus were studied by using Quasiparticle-phonon nuclear model (QPNM). The several of the ground-state and low-lying magnetic dipole (M1) mode characteristics were calculated for deformed odd-mass nuclei using a separable Hamiltonian within the QPNM. The M1 excited states, reduced transition probabilities B(M1), the ground-state magnetic properties such as magnetic moment (μ), intrinsic magnetic moment (gK) , effective spin factor (gseff.) are the fundamental characteristics of the odd-mass nucleus and provide key information to understand nuclear structure. The theoretical results were compared with the available experimental data and other theoretical approaches. Calculations show that the spin-spin interaction in this isotopes leads to polarization effect influencing the magnetic moments. Furthermore we found a strong fragmentation of the M1 strength in 163Dy nucleus which was in qualitative agreement with the experimental data. Sakarya University, Project Number: 2012-50-02-007 and Z.Zenginerler acknowledge to TUBITAK-TURKEY 2013, fellowship No: 2219.
Experimental search for the electron Electric Dipole Moment using solid state techniques
NASA Astrophysics Data System (ADS)
Kim, Y. J.; Liu, C.-Y.; Lamoreaux, S. K.; Reddy, G.
2011-09-01
We report results of an experimental search for the permanent Electric Dipole Moment (EDM) of the electron using a solid state system. The experiment uses a paramagnetic insulator (gadolinium gallium garnet) with a large magnetic response at low temperatures. The presence of the electron EDM leads to a finite magnetization when the garnet sample is subjected to a strong electric field. The resulting magnetization can be measured using a superconducting quantum interference device (SQUID) as a magnetometer. With considerable efforts made towards controlling various sources of systematic effects, the experiment is currently free of spurious signals larger than the SQUID noise. We report the value of electron EDM of (-5.57 ± 7.98 ± 0.12) × 10-25e-cm with 120 hours of data.
The Electric Dipole Moment of Iridium Monosilicide, IrSi
NASA Astrophysics Data System (ADS)
Le, Anh; Steimle, Timothy C.; Cheng, Lan; Stanton, John F.
2013-06-01
The optical spectrum of iridium monosilicide (IrSi) was recently observed using REMPI spectroscopy in the range 17200 to 23850 cm^{-1}. The observation was supported by an ab initio calculation which predicted a X^{2}Δ_{5/2} state. Here, we report on the analysis of the optical Stark effect for the X^{2}Δ_{5/2} and [16.0]1.5 (v=6) states. The (6,0)[16.0]1.5 - X^{2}Δ_{5/2} and the (7,0)[16.0]3.5- X^{2}Δ_{5/2} bands of IrSi have been recorded using high-resolution laser-induced fluorescence spectroscopy. The observed optical Stark shifts for the ^{193}IrSi and ^{191}IrSi isotopologues were analyzed to produce the electric dipole moments of -0.4139(64)D and 0.7821(63)D for the X^{2}Δ_{5/2} and [16.0]1.5 (v=6) states, respectively. The negative sign of electric dipole moment of the X^{2}Δ_{5/2} state is supported by high-level quantum-chemical calculations employing all-electron scalar-relativistic CCSD(T) method augmented with spin-orbit corrections as well as corrections due to full triple excitations. In particular, electron-correlation effects have been shown to be essential in the prediction of the negative sign of the dipole moment. A comparison with other iridium containing molecules will be made. Maria A. Garcia, Carolin Vietz, Fernando Ruipérez, Michael D. Morse, and Ivan Infante, Kimika Fakultatea, Euskal Herriko. J. Chem. Phys., (submitted)
Probing magnetic and electric optical responses of silicon nanoparticles
Permyakov, Dmitry; Sinev, Ivan; Markovich, Dmitry; Samusev, Anton; Belov, Pavel; Ginzburg, Pavel; Valuckas, Vytautas; Kuznetsov, Arseniy I.; Luk'yanchuk, Boris S.; Miroshnichenko, Andrey E.; Neshev, Dragomir N.; Kivshar, Yuri S.
2015-04-27
We study experimentally both magnetic and electric optically induced resonances of silicon nanoparticles by combining polarization-resolved dark-field spectroscopy and near-field scanning optical microscopy measurements. We reveal that the scattering spectra exhibit strong sensitivity of electric dipole response to the probing beam polarization and attribute the characteristic asymmetry of measured near-field patterns to the excitation of a magnetic dipole mode. The proposed experimental approach can serve as a powerful tool for the study of photonic nanostructures possessing both electric and magnetic optical responses.
NASA Astrophysics Data System (ADS)
Sogabe, Yusuke; Sakashita, Masaki; Nakamura, Taketsune; Ogitsu, Toru; Amemiya, Naoyuki
2016-04-01
We carried out electromagnetic field analyses on the cross sections of two dipole magnets wound with coated conductors. One was a cosine-theta magnet, and the other was a block design magnet. The electric field-current density characteristics of the coated conductors were formulated using a percolation depinning model based on the measured voltage-current characteristics. We calculated the temporal evolutions of the current-density distributions in all the turns of each magnet and used these evolutions to calculate the multipole components of the magnetic field. We compared the two magnets, which differed in coated-conductor orientations, regarding the influence of coated-conductor magnetization on the field qualities.
Magnetic dipoles at topological defects in the Meissner state of a nanostructured superconductor
NASA Astrophysics Data System (ADS)
Ge, Jun-Yi; Gladilin, Vladimir N.; Xue, Cun; Tempere, Jacques; Devreese, Jozef T.; Van de Vondel, Joris; Zhou, Youhe; Moshchalkov, Victor V.
2016-06-01
In a magnetic field, superconductivity is manifested by total magnetic field expulsion (Meissner effect) or by the penetration of integer multiples of the flux quantum Φ0. Here we present experimental results revealing magnetic dipoles formed by Meissner current flowing around artificially introduced topological defects (lattice of antidots). By using scanning Hall probe microscopy, we have detected ordered magnetic dipole lattice generated at spatially periodic antidots in a Pb superconducting film. While the conventional homogeneous Meissner state breaks down, the total magnetic flux of the magnetic dipoles remains quantized and is equal to zero. The observed magnetic dipoles strongly depend on the intensity and direction of the locally flowing Meissner current, making the magnetic dipoles an effective way to monitor the local supercurrent. We have also investigated the first step of the vortex depinning process, where, due to the generation of magnetic dipoles, the pinned Abrikosov vortices are deformed and shifted from their original pinning sites.
General magnetic transition dipole moments for electron paramagnetic resonance.
Nehrkorn, Joscha; Schnegg, Alexander; Holldack, Karsten; Stoll, Stefan
2015-01-01
We present general expressions for the magnetic transition rates in electron paramagnetic resonance (EPR) experiments of anisotropic spin systems in the solid state. The expressions apply to general spin centers and arbitrary excitation geometry (Voigt, Faraday, and intermediate). They work for linear and circular polarized as well as unpolarized excitation, and for crystals and powders. The expressions are based on the concept of the (complex) magnetic transition dipole moment vector. Using the new theory, we determine the parities of ground and excited spin states of high-spin (S=5/2) Fe(III) in hemin from the polarization dependence of experimental EPR line intensities. PMID:25615456
750 GeV diphoton resonance and electric dipole moments
NASA Astrophysics Data System (ADS)
Choi, Kiwoon; Im, Sang Hui; Kim, Hyungjin; Mo, Doh Young
2016-09-01
We examine the implication of the recently observed 750 GeV diphoton excess for the electric dipole moments of the neutron and electron. If the excess is due to a spin zero resonance which couples to photons and gluons through the loops of massive vector-like fermions, the resulting neutron electric dipole moment can be comparable to the present experimental bound if the CP-violating angle α in the underlying new physics is of O (10-1). An electron EDM comparable to the present bound can be achieved through a mixing between the 750 GeV resonance and the Standard Model Higgs boson, if the mixing angle itself for an approximately pseudoscalar resonance, or the mixing angle times the CP-violating angle α for an approximately scalar resonance, is of O (10-3). For the case that the 750 GeV resonance corresponds to a composite pseudo-Nambu-Goldstone boson formed by a QCD-like hypercolor dynamics confining at ΛHC, the resulting neutron EDM can be estimated with α ∼(750 GeV /ΛHC) 2θHC, where θHC is the hypercolor vacuum angle.
Electric dipole polarizabilities of hydrogen and helium isotopes
Stetcu, I; Friar, J; Hayes, A C; Quaglioni, S
2009-01-01
The electric dipole polarizabilities of {sup 3}H, {sup 3}He, and {sup 4}He are calculated directly using the Schroedinger equation with the latest generation of two- and three-nucleon interactions. These quantities are necessary in order to obtain accurate nuclear-polarization corrections for transitions involving S-waves in one-and two-electron atoms. Our results are compared to previous results, and it is shown that direct calculations of the electric polarizability of {sup 4}He using modern nuclear potentials are smaller than published values calculated using experimental photoabsorption data. The status of this topic is assessed in the context of precise measurements of transitions in one- and two-electron atoms.
Dipole Model of Electric Pulse Generation Caused by the Relaxation Processes in the Earth's Crust
NASA Astrophysics Data System (ADS)
Losseva, T. V.; Spivak, A.; Kuzmicheva, M. Y.
2011-12-01
Study of electric and magnetic (EM) signals in the Earth's crust is of interest from a viewpoint of both establishing mechanisms and conditions for generation of geophysical fields and interpreting physical and mechanical characteristics of a hierarchically structured medium. In a previously developed model [1] it was proposed that generation of electromagnetic impulses in the Earth's crust with low water content was a result of a quasi independent displacement of a structural block being relaxed in constrained conditions. A transient electric current system generated on an active side of the structural block due to electric polarization of an inter-block gap content was considered as a source of EM radiation. In a new numerical model we use a set of Hertz's dipoles distributed over the active surface. Time dependence of the dipole moments was defined by displacement of the structural unit. To estimate EM signals the full system of Maxwell equations in a conductive medium was solved. The results of numerical simulations were compared with electric field records in a surface layer of the Earth's crust in the area of influence of the tectonically active Kurai structure (Gornyi Altai) [2]. The amplitudes of electric fields at a distance of 50-100 linear block sizes obtained in numerical simulations are in good agreement with the instrumental observations, which proves the validity of our model for the estimation of electric effects in the low moisture rock medium.
Barabanov, A. L.; Golub, R.; Lamoreaux, S. K.
2006-11-15
The search for particle electric dipole moments (EDM's) represents a most promising way to search for physics beyond the standard model. A number of groups are planning a new generation of experiments using stored gases of various kinds. In order to achieve the target sensitivities it will be necessary to deal with the systematic error resulting from the interaction of the well-known v-vectorxE-vector field with magnetic field gradients which is often referred to as the geometric phase effect [E. D. Commins, Am. J. Phys. 59, 1077 (1991); J. M. Pendlebury et al., Phys. Rev. A 70, 032102 (2004)]. This interaction produces a frequency shift linear in the electric field, mimicking an EDM. In this work we introduce an analytic form for the velocity autocorrelation function which determines the velocity-position correlation function which in turn determines the behavior of the frequency shift [S. K. Lamoreaux and R. Golub, Phys. Rev A 71, 032104 (2005)] and show how it depends on the operating conditions of the experiment. We also discuss some additional issues.
Toroid dipole moment as a signature of hybridization, observability by magnetic neutron scattering
NASA Astrophysics Data System (ADS)
Buin, Andrei; de Chatel, Peter
2002-03-01
The current denstity generated by electrons in Russell-Saunders states within an l^n manifold comprises only even-parity multipoles: 'magnetic' dipoles, octopoles, etc. (L=1,3,...) and 'electric' quadrupoles, etc. (L=2,4,...). If inversion symmetry is broken, e.g., by an odd-parity order parameter, and hybridization between states of different parity becomes possible, odd-parity terms also emerge in the multipole expansion of the magnetic field. The L=1 'electric' term describes the field of toroidal currents, which can be modeled by a solenoid bent in a circle. The magnetic neutron scattering amplitude due to such toroidal currents (or, equivalently, ring-shaped magnetization patterns), has a distinct angular dependence on the scattering vector q. If data covering a sufficient variety of q vectors and neutron-spin orientations are available, magnetic and toroidal moments can be distinguished unambiguously. However, it can be shown that within a limited set of data, notably within a plane in q space, which contains the magnetic dipole moment that enables a satisfactory interpretation, a toroid moment can be found, which gives an equally satisfactory result. The possible relevance of this finding to the order parameter in URu2Si2 will be discussed.
Visualizing Special Relativity: The Field of An Electric Dipole Moving at Relativistic Speed
ERIC Educational Resources Information Center
Smith, Glenn S.
2011-01-01
The electromagnetic field is determined for a time-varying electric dipole moving with a constant velocity that is parallel to its moment. Graphics are used to visualize this field in the rest frame of the dipole and in the laboratory frame when the dipole is moving at relativistic speed. Various phenomena from special relativity are clearly…
Electric dipole radiation at VLF in a uniform warm magneto-plasma.
NASA Technical Reports Server (NTRS)
Wang, T. N. C.; Bell, T. F.
1972-01-01
Use of a linear full electromagnetic wave theory to calculate the input impedance of an electric antenna embedded in a uniform, lossless, unbounded warm magnetoplasma, which is assumed to consist of warm electrons and cold ions. In calculating the dipole radiation resistance for the thermal modes and the thermally modified whistler mode the analysis includes the finite temperature only for the electrons. In deriving the formal solution of the warm plasma dipole input impedance a full-wave analysis is used and two antenna orientations are considered, parallel and perpendicular to the static magnetic field. A general dispersion equation governing the modes of propagation is derived and a detailed analysis is made of the propagation characteristics of these modes.
Space propulsion by fusion in a magnetic dipole
Teller, E.; Glass, A.J.; Fowler, T.K. ); Hasegawa, A. ); Santarius, J.F. . Fusion Technology Inst.)
1991-04-12
A conceptual design is discussed for a fusion rocket propulsion system based on the magnetic dipole configuration. The dipole is found to have features well suited to space applications. Example parameters are presented for a system producing a specific power of 1 kW/kg, capable of interplanetary flights to Mars in 90 days and to Jupiter in a year, and of extra-solar-system flights to 1000 astronomical units (the Tau mission) in 20 years. This is about 10 times better specific power toward 10 kW/kg are discussed, as in an approach to implementing the concept through proof-testing on the moon. 21 refs., 14 figs., 2 tabs.
Electromagnetic drag on a magnetic dipole near a translating conducting bar
NASA Astrophysics Data System (ADS)
Kirpo, Maksims; Tympel, Saskia; Boeck, Thomas; Krasnov, Dmitry; Thess, André
2011-06-01
The electromagnetic drag force and torque acting on a magnetic dipole due to the translatory motion of an electrically conducting bar with square cross section and infinite length is computed by numerical analysis for different orientations and locations of the dipole. The study is motivated by the novel techniques termed Lorentz force velocimetry and Lorentz force eddy current testing for noncontact measurements of the velocity of a conducting liquid and for detection of defects in the interior of solid bodies, respectively. The present, simplified configuration provides and explains important scaling laws and reference results that can be used for verification of future complete numerical simulations of more realistic problems and complex geometries. The results of computations are also compared with existing analytical solutions for an infinite plate and with a newly developed asymptotic theory for large distances between the bar and the magnetic dipole. We finally discuss the optimization problem of finding the orientation of the dipole relative to the bar that produces the maximum force in the direction of motion.
Enhancement of magnetic dipole emission at yellow light in optical metamaterials
NASA Astrophysics Data System (ADS)
Hu, Wenliang; Yi, Ningbo; Sun, Shang; Cui, Lin; Song, Qinghai; Xiao, Shumin
2015-09-01
Here we demonstrate the control of magnetic dipole spontaneous emission at yellow light by magnetic metamaterials. By embedding magnetic dipole into a magnetic metamaterial consisting of arrays of paired silver strips, the radiative emission enhancement and the Purcell factor around 590 nm has been dramatically increased to 110 and 180 respectively. Moreover, the enhancements are found to be robust to variation of dipole's positions and structure geometries, showing nice fabrication tolerance for practical applications.
Efficient injection of an intense positron beam into a dipole magnetic field
NASA Astrophysics Data System (ADS)
Saitoh, H.; Stanja, J.; Stenson, E. V.; Hergenhahn, U.; Niemann, H.; Pedersen, T. Sunn; Stoneking, M. R.; Piochacz, C.; Hugenschmidt, C.
2015-10-01
We have demonstrated efficient injection and trapping of a cold positron beam in a dipole magnetic field configuration. The intense 5 eV positron beam was provided by the NEutron induced POsitron source MUniCh facility at the Heinz Maier-Leibnitz Zentrum, and transported into the confinement region of the dipole field trap generated by a supported, permanent magnet with 0.6 T strength at the pole faces. We achieved transport into the region of field lines that do not intersect the outer wall using the {E}× {B} drift of the positron beam between a pair of tailored plates that created the electric field. We present evidence that up to 38% of the beam particles are able to reach the intended confinement region and make at least a 180° rotation around the magnet where they annihilate on an insertable target. When the target is removed and the {E}× {B} plate voltages are switched off, confinement of a small population persists for on the order of 1 ms. These results lend optimism to our larger aims to apply a magnetic dipole field configuration for trapping of both positrons and electrons in order to test predictions of the unique properties of a pair plasma.
Search for electric dipole moment in 129Xe atom using active nuclear spin maser
NASA Astrophysics Data System (ADS)
Ichikawa, Y.; Chikamori, M.; Ohtomo, Y.; Hikota, E.; Sakamoto, Y.; Suzuki, T.; Bidinosti, C. P.; Inoue, T.; Furukawa, T.; Yoshimi, A.; Suzuki, K.; Nanao, T.; Miyatake, H.; Tsuchiya, M.; Yoshida, N.; Shirai, H.; Ino, T.; Ueno, H.; Matsuo, Y.; Fukuyama, T.; Asahi, K.
2014-03-01
An experimental search for an electric dipole moment in the diamagnetic atom 129Xe is in progress through the precision measurement of spin precession frequency using an active nuclear spin maser. A 3He comagnetometer has been incorporated into the active spin maser system in order to cancel out the long-term drifts in the external magnetic field. Also, a double-cell geometry has been adopted in order to suppress the frequency shifts due to interaction with polarized Rb atoms. The first EDM measurement with the 129Xe active spin maser and the 3He comagnetometer has been conducted.
Improved experimental limit on the electric dipole moment of the neutron.
Baker, C A; Doyle, D D; Geltenbort, P; Green, K; van der Grinten, M G D; Harris, P G; Iaydjiev, P; Ivanov, S N; May, D J R; Pendlebury, J M; Richardson, J D; Shiers, D; Smith, K F
2006-09-29
An experimental search for an electric dipole moment (EDM) of the neutron has been carried out at the Institut Laue-Langevin, Grenoble. Spurious signals from magnetic-field fluctuations were reduced to insignificance by the use of a cohabiting atomic-mercury magnetometer. Systematic uncertainties, including geometric-phase-induced false EDMs, have been carefully studied. The results may be interpreted as an upper limit on the neutron EDM of |d(n)|< 2.9 x 10(-26)e cm (90% C.L.). PMID:17026025
Improved Experimental Limit on the Electric Dipole Moment of the Neutron
Baker, C. A.; Iaydjiev, P.; Ivanov, S. N.; Doyle, D. D.; Harris, P. G.; May, D. J. R.; Pendlebury, J. M.; Richardson, J. D.; Shiers, D.; Smith, K. F.; Geltenbort, P.; Green, K.; Grinten, M. G. D. van der
2006-09-29
An experimental search for an electric dipole moment (EDM) of the neutron has been carried out at the Institut Laue-Langevin, Grenoble. Spurious signals from magnetic-field fluctuations were reduced to insignificance by the use of a cohabiting atomic-mercury magnetometer. Systematic uncertainties, including geometric-phase-induced false EDMs, have been carefully studied. The results may be interpreted as an upper limit on the neutron EDM of vertical bar d{sub n} vertical bar <2.9x10{sup -26}e cm (90% C.L.)
Reorientable electric dipoles and cooperative phenomena in human tooth enamel.
Hitmi, N; Lamure-Plaino, E; Lamure, A; LaCabanne, C; Young, R A
1986-05-01
A preliminary investigation of electric dipole reorientability in human tooth enamel (TE) in comparison to that in hydroxyapatite (OHAp) has been made with the fractional-polarization form of the thermally stimulated currents (TSC) method. The reorientable dipoles are the structural OH-ions. The OHAp exhibited compensation phenomena at 211.5 degrees C and at 356 degrees C which are associated here with the hexagonal form becoming quasi-statically stabilized and dynamically stabilized, respectively, against the monoclinic form. TE specimens were pretreated at various temperatures. All showed the onset of cooperative motions that could quasi-statically stabilize the hexagonal form at the same temperature, approximately 212 degrees C, as did OHAp, even though the TE was already statically stabilized in the hexagonal form. Parts of the TSC spectra that did not conform to the 212 degrees C compensation changed progressively with pretreatment temperature. Loss of incorporated H2O is identified as the most probable cause of most of these changes. This work shows considerable promise for TSC as a tool for further quantitative investigation of TE. PMID:3013384
Hadronic electric dipole moments in R-parity violating supersymmetry
Faessler, Amand; Gutsche, Thomas; Lyubovitskij, Valery E.; Kovalenko, Sergey
2006-06-01
We calculate the electric dipole moments (EDM) of the neutral {sup 199}Hg atom, neutron and deuteron within a generic R-parity violating SUSY model (Re{sub p} SUSY) on the basis of a one-pion-exchange model with CP-odd pion-nucleon interactions. We consider two types of the Re{sub p} SUSY contributions to the above hadronic EDMs: via the quark chromoelectric dipole moments (CEDM) and CP-violating 4-quark interactions. We demonstrate that the former contributes to all the three studied EDMs while the latter appears only in the nuclear EDMs via the CP-odd nuclear forces. We find that the Re{sub p} SUSY induced 4-quark interactions arise at tree level through the sneutrino exchange and involve only s and b quarks. Therefore, their effect in hadronic EDMs is determined by the strange and bottom-quark sea of the nucleon. From the null experimental results on the hadronic EDMs we derive the limits on the imaginary parts of certain products Im({lambda}{sup '}{lambda}{sup '}*) of the trilinear Re{sub p}-couplings and show that the currently best limits come from the {sup 199}Hg EDM experiments. We demonstrate that some of these limits are better than those existing in the literature. We argue that future storage ring experiments on the deuteron EDM are able to improve these limits by several orders of magnitude.
Green, M.A.
1991-05-01
Higher multipoles due to magnetization of the superconductor in four and five centimeter bore Superconducting Super Collider (SSC) superconducting dipole magnets have been observed. The use of passive superconductor to correct out the magnetization sextupole has been demonstrated on two dipoles built by the Lawrence Berkeley Laboratory (LBL). This reports shows how passive correction can be applied to the five centimeter SSC dipoles to remove sextupole and decapole caused by magnetization of the dipole superconductor. Two passive superconductor corrector options will be presented. The change in magnetization sextupole and decapole due to flux creep decay of the superconductor during injection can be partially compensated for using the passive superconductor. 9 refs; 5 figs.
The permanent electric dipole moment of CaOH
NASA Technical Reports Server (NTRS)
Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Steimle, Timothy; Shirley, Jeffrey E.
1990-01-01
The X 2 Sigma(+), A 2Pi, and B 2Sigma(+) states of CaOH are characterized theoretically and experimentally, with a focus on the value of the permanent electric dipole moment (mu). Calculations based on SCF and SDCI studies of CaOH (Bauschlicher et al., 1984 and 1986) give mu values of 0.98, 0.49, and 0.11 D for the X, A, and B states, respectively, in good agreement with experiments in which the pure rotational spectra of these states were not detected. Modified Rittner (1951) and ligand-field models of these states are explored in detail, and the applicability of these results to observational searches for CaOH in circumstellar envelopes is indicated.
The quest for an electric dipole moment of the neutron
NASA Astrophysics Data System (ADS)
Schmidt-Wellenburg, P.
2016-07-01
To date no electric dipole moment of the neutron (nEDM) has been observed. Why it is so vanishing small, escaping detection in the last 50 years, is not easy to explain. In general it is considered as the most sensitive probe for the violation of the combined symmetry of charge and parity (CP). A discovery could shed light on the poorly understood matter/anti-matter asymmetry of the universe. The neutron might one day help to distinguish different sources of CP-violation in combination with measurements of the electron and diamagnetic EDMs. This proceedings article presents an overview of the most important concepts in searches for an nEDM and presents a brief overview of the world wide efforts.
Thermal annealing-induced electric dipole relaxation in natural alexandrite
NASA Astrophysics Data System (ADS)
Scalvi, Rosa M. Fernandes; Li, Maximo Siu; Scalvi, Luis V. A.
2005-02-01
Electrical properties of natural alexandrite (BeAl2O4:Cr3+) are investigated by the thermally stimulated depolarization current (TSDC) technique. Samples are submitted to consecutive annealing processes and TSDC is carried out after each annealing, yielding bands with different parameters. These bands are fitted by a continuous distribution of relaxation parameters: activation energy and pre-exponential factor of the Arrhenius equation. It has been observed that annealing influences the dipole relaxation behavior, since it promotes a modification of Fe3+ and Cr3+ impurity distributions on sites of distinct symmetry: Al1 and Al2. In order to have a reference for comparison, TSDC is also carried out on a synthetic alexandrite sample, where the only impurity present is Cr3+ ion.
Electroweak baryogenesis, electric dipole moments, and Higgs diphoton decays
NASA Astrophysics Data System (ADS)
Chao, Wei; Ramsey-Musolf, Michael J.
2014-10-01
We study the viability of electroweak baryogenesis in a two Higgs doublet model scenario augmented by vector-like, electroweakly interacting fermions. Considering a limited, but illustrative region of the model parameter space, we obtain the observed cosmic baryon asymmetry while satisfying present constraints from the non-observation of the permanent electric dipole moment (EDM) of the electron and the combined ATLAS and CMS result for the Higgs boson diphoton decay rate. The observation of a non-zero electron EDM in a next generation experiment and/or the observation of an excess (over the Standard Model) of Higgs to diphoton events with the 14 TeV LHC run or a future e + e - collider would be consistent with generation of the observed baryon asymmetry in this scenario.
Nuclear electric dipole moment of {sup 3}He
Stetcu, I.; Friar, J. L.; Hayes, A. C.; Liu, C.-P.; Navratil, P.
2009-01-28
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.
Improved limit on the muon electric dipole moment
Bennett, G. W.; Brown, H. N.; Bunce, G.; Danby, G. T.; Larsen, R.; Lee, Y. Y.; Meng, W.; Mi, J.; Morse, W. M.; Nikas, D.; Prigl, R.; Semertzidis, Y. K.; Warburton, D.; Bousquet, B.; Cushman, P.; Duong, L.; Giron, S.; Kindem, J.; Kronkvist, I.; Qian, T.
2009-09-01
Three independent searches for an electric dipole moment (EDM) of the positive and negative muons have been performed, using spin precession data from the muon g-2 storage ring at Brookhaven National Laboratory. Details on the experimental apparatus and the three analyses are presented. Since the individual results on the positive and negative muons, as well as the combined result, d{sub {mu}}=(0.0{+-}0.9)x10{sup -19}e cm, are all consistent with zero, we set a new muon EDM limit, |d{sub {mu}}|<1.8x10{sup -19}e cm (95% C.L.). This represents a factor of 5 improvement over the previous best limit on the muon EDM.
Toward verification of electroweak baryogenesis by electric dipole moments
NASA Astrophysics Data System (ADS)
Fuyuto, Kaori; Hisano, Junji; Senaha, Eibun
2016-04-01
We study general aspects of the CP-violating effects on the baryon asymmetry of the Universe (BAU) and electric dipole moments (EDMs) in models extended by an extra Higgs doublet and a singlet, together with electroweak-interacting fermions. In particular, the emphasis is on the structure of the CP-violating interactions and dependences of the BAU and EDMs on masses of the relevant particles. In a concrete mode, we investigate a relationship between the BAU and the electron EDM for a typical parameter set. As long as the BAU-related CP violation predominantly exists, the electron EDM has a strong power in probing electroweak baryogenesis. However, once a BAU-unrelated CP violation comes into play, the direct correlation between the BAU and electron EDM can be lost. Even in such a case, we point out that verifiability of the scenario still remains with the help of Higgs physics.
Electric dipole moment constraints on minimal electroweak baryogenesis
Huber, Stephan J.; Pospelov, Maxim; Ritz, Adam
2007-02-01
We study the simplest generic extension of the standard model which allows for conventional electroweak baryogenesis, through the addition of dimension-six operators in the Higgs sector. At least one such operator is required to be CP-odd, and we study the constraints on such a minimal setup, and related scenarios with minimal flavor violation, from the null results of searches for electric dipole moments (EDMs), utilizing the full set of two-loop contributions to the EDMs. The results indicate that the current bounds are stringent, particularly that of the recently updated neutron EDM, but fall short of ruling out these scenarios. The next generation of EDM experiments should be sufficiently sensitive to provide a conclusive test.
NASA Astrophysics Data System (ADS)
Lazzeretti, P.; Malagoli, M.; Turci, L.; Zanasi, R.
1993-10-01
Theoretical methods based on the random-phase approximation have been applied to evaluate near Hartree-Fock dynamic electric polarizability and shielding tensors of carbon and hydrogen nuclei in the benzene molecule. Cauchy moments of the various properties have been determined. The results obtained in different gauges (dipole length, velocity, and acceleration) are reported.
Beam induced electron cloud resonances in dipole magnetic fields
NASA Astrophysics Data System (ADS)
Calvey, J. R.; Hartung, W.; Makita, J.; Venturini, M.
2016-07-01
The buildup of low energy electrons in an accelerator, known as electron cloud, can be severely detrimental to machine performance. Under certain beam conditions, the beam can become resonant with the cloud dynamics, accelerating the buildup of electrons. This paper will examine two such effects: multipacting resonances, in which the cloud development time is resonant with the bunch spacing, and cyclotron resonances, in which the cyclotron period of electrons in a magnetic field is a multiple of bunch spacing. Both resonances have been studied directly in dipole fields using retarding field analyzers installed in the Cornell Electron Storage Ring. These measurements are supported by both analytical models and computer simulations.
Magnetic field measurements of full length 50 mm aperture SSC dipole magnets at Fermilab
Strait, J.; Bossert, R.; Carson, J.; Delchamps, S.W.; Gourlay, S.; Hanft, R.; Koska, W.; Kuchnir, M.; Lamm, M.J.; Mazur, P.O.; Mokhtarani, A.; Orris, D.; Ozelis, J.; Wake, M. ); Devred, A.; DiMarco, J.; Kuzminski, J.; Puglisi, M.; Tompkins, J.C.; Yu, Y.; Zhao, Y.; Zheng, H. ); Ogitsu, T. (Supe
1992-09-01
Thirteen 16 m long, 50 mm aperture SSC dipole magnets, designed jointly by Fermilab, Brookhaven National Laboratory, Lawrence Berkeley Laboratory and the SSC Laboratory, have been built at Fermilab. The first nine magnets have been fully tested to date. The allowed harmonics are systematically shifted from zero by amounts larger than the specification. The unallowed harmonics, with the exception of the skew sextupole, are consistent with zero. The magnet-to-magnet RMS variation of all harmonics is much smaller than the specification.
The electric dipole moment of magnesium deuteride, MgD
NASA Astrophysics Data System (ADS)
Steimle, Timothy C.; Zhang, Ruohan; Wang, Hailing
2014-06-01
The (0,0) A2Π-X 2Σ+ band of a cold molecular beam sample of magnesium monodeuteride, MgD, has been recorded field-free and in the presence of a static electric field of up to 11 kV/cm. The lines associated with the lowest rotational levels are detected for the first time. The field-free spectrum was analyzed to produce an improved set of fine structure parameters for the A2Π (v = 0) state. The observed electric field induced splittings and shifts were analyzed to produce permanent electric dipole moments, ěc μ _{el} of 2.567(10)D and 1.31(8)D for A2Π (v = 0) and X2Σ+(v = 0) states, respectively. The recommended value for ěc μ _{el}(X2Σ+ (v = 0)) for MgH, based upon the measured value for MgD, is 1.32(8)D.
The electric dipole moment of magnesium deuteride, MgD
Steimle, Timothy C. Zhang, Ruohan; Wang, Hailing
2014-06-14
The (0,0) A{sup 2}Π–X {sup 2}Σ{sup +} band of a cold molecular beam sample of magnesium monodeuteride, MgD, has been recorded field-free and in the presence of a static electric field of up to 11 kV/cm. The lines associated with the lowest rotational levels are detected for the first time. The field-free spectrum was analyzed to produce an improved set of fine structure parameters for the A{sup 2}Π (v = 0) state. The observed electric field induced splittings and shifts were analyzed to produce permanent electric dipole moments, μ{sup -vector}{sub el} of 2.567(10)D and 1.31(8)D for A{sup 2}Π (v = 0) and X{sup 2}Σ{sup +}(v = 0) states, respectively. The recommended value for μ{sup -vector}{sub el}(X{sup 2}Σ{sup +} (v = 0)) for MgH, based upon the measured value for MgD, is 1.32(8)D.
Systematics in a measurement of the electron's electric dipole moment using trapped molecular ions
NASA Astrophysics Data System (ADS)
Grau, Matt; Cossel, Kevin; Cairncross, William; Gresh, Dan; Zhou, Yan; Ye, Jun; Cornell, Eric
2015-05-01
A precision measurement of the electron's electric dipole moment (EDM) has important implications for physics beyond the Standard Model. Trapped molecular ions offer high sensitivity in such an experiment because of the large effective electric fields and long coherence times that are possible. Our experiment uses Ramsey spectroscopy of HfF+ ions in a linear RF trap with rotating bias fields, achieving coherence times beyond 1 second for 1000 trapped ions. Compared to other electron EDM experiments that use molecular beams, we will be sensitive to a different class of systematic errors. In this work we investigate systematic errors arising from all fields involved in the experiment, including the trapping and polarizing electric fields, magnetic field gradients, and motional effects such as geometric phases. This work was supported by NIST and NSF.
Fabrication and test results of a high field, Nb3Sn superconducting racetrack dipole magnet
Benjegerdes, R.; Bish, P.; Byford, D.; Caspi, S.; Dietderich, D.R.; Gourlay, S.A.; Hafalia, R.; Hannaford, R.; Higley, H.; Jackson, A.; Lietzke, A.; Liggins, N.; McInturff, A.D.; O'Neill, J.; Palmerston, E.; Sabbi, G.; Scanlan, R.M.; Swanson, J.
2001-06-15
The LBNL Superconducting Magnet Program is extending accelerator magnet technology to the highest possible fields. A 1 meter long, racetrack dipole magnet, utilizing state-of-the-art Nb{sub 3}Sn superconductor, has been built and tested. A record dipole filed of 14.7 Tesla has been achieved. Relevant features of the final assembly and tested results are discussed.
Local electric dipole moments for periodic systems via density functional theory embedding.
Luber, Sandra
2014-12-21
We describe a novel approach for the calculation of local electric dipole moments for periodic systems. Since the position operator is ill-defined in periodic systems, maximally localized Wannier functions based on the Berry-phase approach are usually employed for the evaluation of local contributions to the total electric dipole moment of the system. We propose an alternative approach: within a subsystem-density functional theory based embedding scheme, subset electric dipole moments are derived without any additional localization procedure, both for hybrid and non-hybrid exchange-correlation functionals. This opens the way to a computationally efficient evaluation of local electric dipole moments in (molecular) periodic systems as well as their rigorous splitting into atomic electric dipole moments. As examples, Infrared spectra of liquid ethylene carbonate and dimethyl carbonate are presented, which are commonly employed as solvents in Lithium ion batteries. PMID:25527922
Local electric dipole moments for periodic systems via density functional theory embedding
NASA Astrophysics Data System (ADS)
Luber, Sandra
2014-12-01
We describe a novel approach for the calculation of local electric dipole moments for periodic systems. Since the position operator is ill-defined in periodic systems, maximally localized Wannier functions based on the Berry-phase approach are usually employed for the evaluation of local contributions to the total electric dipole moment of the system. We propose an alternative approach: within a subsystem-density functional theory based embedding scheme, subset electric dipole moments are derived without any additional localization procedure, both for hybrid and non-hybrid exchange-correlation functionals. This opens the way to a computationally efficient evaluation of local electric dipole moments in (molecular) periodic systems as well as their rigorous splitting into atomic electric dipole moments. As examples, Infrared spectra of liquid ethylene carbonate and dimethyl carbonate are presented, which are commonly employed as solvents in Lithium ion batteries.
Local electric dipole moments for periodic systems via density functional theory embedding
Luber, Sandra
2014-12-21
We describe a novel approach for the calculation of local electric dipole moments for periodic systems. Since the position operator is ill-defined in periodic systems, maximally localized Wannier functions based on the Berry-phase approach are usually employed for the evaluation of local contributions to the total electric dipole moment of the system. We propose an alternative approach: within a subsystem-density functional theory based embedding scheme, subset electric dipole moments are derived without any additional localization procedure, both for hybrid and non-hybrid exchange–correlation functionals. This opens the way to a computationally efficient evaluation of local electric dipole moments in (molecular) periodic systems as well as their rigorous splitting into atomic electric dipole moments. As examples, Infrared spectra of liquid ethylene carbonate and dimethyl carbonate are presented, which are commonly employed as solvents in Lithium ion batteries.
Local spin dynamics with the electron electric dipole moment
NASA Astrophysics Data System (ADS)
Fukuda, Masahiro; Soga, Kota; Senami, Masato; Tachibana, Akitomo
2016-01-01
The local spin dynamics of the electron is studied from the viewpoint of the electric dipole moment (EDM) of the electron in the framework of the quantum field theory. The improvements of the computational accuracy of the effective electric field (Eeff) for the EDM and the understanding of spin precession are important for the experimental determination of the upper bound of the EDM. Calculations of Eeff in YbF (2Σ1 /2 ), BaF (2Σ1 /2 ), ThO (3Δ1 ), and HF+ (2Π1 /2 ) are performed on the basis of the restricted active space configuration interaction approach by using the four-component relativistic electronic structure calculation. The spin precession is also discussed from the viewpoint of local spin torque dynamics. We show that a contribution to the torque density for the spin is brought into by the EDM. Distributions of the local spin angular momentum density and torque densities induced by external fields in the above molecules are calculated and a property related with large Eeff is discussed.
Neutron electric dipole moment measurement with a buffer gas comagnetometer
NASA Astrophysics Data System (ADS)
Masuda, Yasuhiro; Asahi, Koichiro; Hatanaka, Kichiji; Jeong, Sun-Chan; Kawasaki, Shinsuke; Matsumiya, Ryohei; Matsuta, Kensaku; Mihara, Mototsugu; Watanabe, Yutaka
2012-03-01
A neutron EDM measurement with a comagnetometer is discussed. For magnetometry, polarized xenon atoms are injected into a cylindrical cell where a cylindrically symmetric magnetic field and an electric field are applied for the EDM measurement. The geometric phase effect (GPE), which originates from particle motion in a magnetic field gradient, is analyzed in terms of the Dyson series. The motion of the xenon atom is largely suppressed because of a small mean free path. The field gradient is controlled by means of NMR measurements, where the false effect of Earth's rotation is removed. As a result, the GPE is reduced below 10-28e cm.
Nonadiabatic behavior of the magnetic moment of a charged particle in a dipole magnetic field
NASA Technical Reports Server (NTRS)
Murakami, Sadayoshi; Sato, Tetsuya; Hasegawa, Akira
1990-01-01
This paper investigates the dynamic behavior of the magnetic moment of a particle confined in a magnetic dipole field in the presence of a low-frequency electrostatic wave. It is shown that there exist two kinds of resonances (the bounce-E x B drift resonance and the wave-drift resonance) by which the adiabaticity of the magnetic moment is broken. The unstable conditions obtained by theoretical considerations showed good agreement with the numerical results.
Communication: theoretical study of ThO for the electron electric dipole moment search.
Skripnikov, L V; Petrov, A N; Titov, A V
2013-12-14
An experiment to search for the electron electric dipole moment (eEDM) on the metastable H(3)Δ1 state of ThO molecule was proposed and now prepared by the ACME Collaboration [http://www.electronedm.org]. To interpret the experiment in terms of eEDM and dimensionless constant kT, P characterizing the strength of the T,P-odd pseudoscalar-scalar electron-nucleus neutral current interaction, an accurate theoretical study of an effective electric field on electron, Eeff, and a parameter of the T,P-odd pseudoscalar-scalar interaction, WT, P, in ThO is required. We report our results for Eeff (84 GV/cm) and WT, P (116 kHz) together with the hyperfine structure constant, molecule frame dipole moment, and H(3)Δ1 → X(1)Σ(+) transition energy, which can serve as a measure of reliability of the obtained Eeff and WT, P values. Besides, our results include a parity assignment and evaluation of the electric-field dependence for the magnetic g factors in the Ω-doublets of H(3)Δ1. PMID:24329049
Search for Electric dipole moment (EDM) in laser cooled and trapped 225Ra atoms
NASA Astrophysics Data System (ADS)
Kalita, Mukut; Bailey, Kevin; Dietrich, Matthew; Green, John; Holt, Roy; Korsch, Wolfgang; Lu, Zheng-Tian; Lemke, Nathan; Mueller, Peter; O'Connor, Tom; Parker, Richard; Singh, Jaideep; Trimble, Will; Argonne National Laboratory Collaboration; University Of Chicago Collabration; University Of Kentucky Collaboration
2014-05-01
We are searching for an EDM of the diamagnetic 225Ra atom. 225Ra has nuclear spin I =1/2. Experimental sensitivity to its EDM is enhanced due to its heavy mass and the increased Schiff moment of its octupole deformed nucleus. Our experiment involves collecting laser cooled Ra atoms in a magneto-optical trap (MOT), transporting them 1 meter with a far off-resonant optical dipole trap (ODT) and then transferring the atoms to a second standing-wave ODT in our experimental chamber. We will report our recent experiences in polarizing and observing Larmor precession of 225Ra atoms in parallel electric and magnetic fields in a magnetically shielded region and progress towards a first measurement of the EDM of 225Ra. This work is supported by DOE, Office of Nuclear Physics, under contract No. DE-AC02-06CH11357 and contract No. DE-FG02-99ER41101.
First Atomic Electric Dipole Moment Limit Derived from an Octupole-Deformed Nucleus
NASA Astrophysics Data System (ADS)
Parker, Richard; Bishof, Michael; Kalita, Mukut; Lemke, Nathan; Dietrich, Matt; Bailey, Kevin; Greene, John; Holt, Roy; Korsch, Wolfgang; Lu, Zheng-Tian; Mueller, Peter; O'Connor, T. P.; Singh, Jaideep
2015-05-01
Ra-225 (half-life = 15 d, nuclear spin = 1/2) is a promising isotope for a measurement of the EDM of a diamagnetic atom. Due to its large nuclear octupole deformation and high atomic mass, the EDM sensitivity of Ra-225 is expected to be 2-3 orders of magnitude larger than that of Hg-199. We demonstrate an efficient multiple-stage apparatus in which radium atoms are first loaded into a MOT, then transferred into a movable optical-dipole trap (ODT) that carries the atoms over 1 m to a magnetically-shielded science chamber, loaded into a standing-wave ODT, polarized, and then allowed to precess in magnetic and electric fields. We will discuss our first measurement of the EDM of Ra-225, as well as plans for future improvements. This work is supported by DOE, Office of Nuclear Physics (DE-AC02-06CH11357).
MAGNETIC MODELING VS MEASUREMENTS OF THE DIPOLES FOR THE JLAB 10 KW FREE ELECTRON LASER UPGRADE
David Douglas; Robin Wines; Tom Hiatt; George Biallas; Kenneth Baggett; T.J. Schultheiss; V.A. Christina; J.W. Rathke; A. Smirnov; D. Newsham; Y. Luo; D. Yu
2003-05-01
Magnetic measurements of the six families of dipoles for the infrared Free Electron Laser Upgrade at the Thomas Jefferson National Accelerator Facility (Jlab) are compared to the magnetic models on which their design is based. The magnets were designed in parallel by three organizations. They used ANSYS, Radia or Opera 3D as a 3D magnetic modeling program. Comparison of the discrepancies between model and magnet measurement is presented along with analysis of their potential causes. These dipoles operate in two field ranges. The Injector/ Extractor Dipoles operate around 0.05 T and the Arc Dipoles and Optical Chicane Dipoles operate between 0.22 to 0.71 T. All magnets are required to meet core field and field integral flatness to parts in 104 over their good field region.