Nuclear quadrupole moment of the 99Tc ground state
International Nuclear Information System (INIS)
Errico, Leonardo; Darriba, German; Renteria, Mario; Tang Zhengning; Emmerich, Heike; Cottenier, Stefaan
2008-01-01
By combining first-principles calculations and existing nuclear magnetic resonance (NMR) experiments, we determine the quadrupole moment of the 9/2 + ground state of 99 Tc to be (-)0.14(3)b. This confirms the value of -0.129(20)b, which is currently believed to be the most reliable experimental determination, and disagrees with two earlier experimental values. We supply ab initio calculated electric-field gradients for Tc in YTc 2 and ZrTc 2 . If this calculated information would be combined with yet to be performed Tc-NMR experiments in these compounds, the error bar on the 99 Tc ground state quadrupole moment could be further reduced
Measurement of the ground state spectroscopic quadrupole moments of 191Os and 193Os
International Nuclear Information System (INIS)
Ernst, H.; Hagn, E.; Zech, E.
1979-01-01
Radioactive 191 Os and 193 Os nuclei have been aligned in an Os single crystal at temperatures down to 4 mK. From the temperature dependence of the γ-anisotropy the quadrupole frequencies vsub(Q) = e 2 qQ/h have been determined as vsub(Q)( 191 OsOs) = -278+-9 MHz and vsub(Q)( 193 OsOs) = -96+-15 MHz. With the known electric field gradient for OsOs of eq = (-4.54+-0.24) x 10 17 V/cm 2 the ground state spectroscopic quadrupole moments are deduced to be Q( 191 Os) = +2.53+-0.16 b and Q( 193 Os) = +0.87+-0.15 b. (orig.)
International Nuclear Information System (INIS)
Antony, M.S.; Britz, J.
1986-01-01
A compilation of experimental root-mean square radii, isotope shifts, ground-state magnetic dipole and electric quadrupole moments of nuclei 1≤A≤239 is presented. Shell, sub-subshell closures and changes in nuclear deformations discernible from data are displayed graphically. The nuclear charge distribution, for 1≤A≤ 239 nuclei deduced from Coulomb displacement energies is shown for comparison
International Nuclear Information System (INIS)
Krivoruchenko, M.I.
1985-01-01
In chiral bag model an expression is obtained for the quark wave functions with account of color and pion interaction of quarks. The quadrupole moments of nonstrange hadrons are calculated. Quadrupole moment of nucleon isobar is found to be Q(Δ)=-6.3x10 -28 esub(Δ)(cm)sup(2). Fredictions of the chiral bag model are in strong disagreement with the non-relativistic quark model
Table of Nuclear Electric Quadrupole Moments
International Nuclear Information System (INIS)
Stone, N.J.
2013-12-01
This Table is a compilation of experimental measurements of static electric quadrupole moments of ground states and excited states of atomic nuclei throughout the periodic table. To aid identification of the states, their excitation energy, half-life, spin and parity are given, along with a brief indication of the method and any reference standard used in the particular measurement. Experimental data from all quadrupole moment measurements actually provide a value of the product of the moment and the electric field gradient [EFG] acting at the nucleus. Knowledge of the EFG is thus necessary to extract the quadrupole moment. A single recommended value of the moment is given for each state, based, for each element, wherever possible, upon a standard reference moment for a nuclear state of that element studied in a situation in which the electric field gradient has been well calculated. For several elements one or more subsidiary reference EFG/moment references are required and their use is specified. The literature search covers the period to mid-2013. (author)
Ground state energy values and moments of the anharmonic oscillator
International Nuclear Information System (INIS)
Seetharaman, M.; Raghavan, Sekhar; Subba Rao, G.
1981-01-01
It is shown that a very satisfactory estimate of the energy values (for all values of the anharmonicity) and moments of the ground state of the quartic anharmonic oscillator can be obtained in the variational method, by considering trial wavefunctions which have the correct asymptotic properties. The results derived with a single variational parameter are a considerable improvement over the recent results of C.A. Ginsburg and E.W. Montroll (1978). (author)
Table of Nuclear Magnetic Dipole and Electric Quadrupole Moments
International Nuclear Information System (INIS)
Stone, N.J.
2011-04-01
This Table is a compilation of experimental measurements of static magnetic dipole and electric quadrupole moments of ground states and excited states of atomic nuclei throughout the periodic table. To aid identification of the states, their excitation energy, half-life, spin and parity are given, along with a brief indication of the method and any reference standard used in the particular measurement. The literature search covers the period to late 2010. Many of the entries prior to 1988 follow those in Raghavan P., Atomic and Nuclear Data Tables 42, 189 (1989). (author)
Table of Nuclear Magnetic Dipole and Electric Quadrupole Moments
International Nuclear Information System (INIS)
Stone, N.J.
2014-02-01
This Table is a compilation of experimental measurements of static magnetic dipole and electric quadrupole moments of ground states and excited states of atomic nuclei throughout the periodic table. To aid identification of the states, their excitation energy, half-life, spin and parity are given, along with a brief indication of the method and any reference standard used in the particular measurement. The literature search covers the period to early 2014. Many of the entries prior to 1988 follow those in Raghavan P., Atomic and Nuclear Data Tables 42, 189 (1989). (author)
Relativistic Quadrupole Polarizability for the Ground State of Hydrogen-Like Ions
International Nuclear Information System (INIS)
Zhang Yong-Hu; Zhang Xian-Zhou; Tang Li-Yan; Shi Ting-Yun; Mitroy Jim
2012-01-01
The static quadrupole polarizabilities for hydrogen-like ions from Z = 1 to Z = 100 in the 1S 1/2 ground state are calculated to high precision by solving the Dirac equation using the B-spline Galerkin method. The results are consistent with the expression of Kaneko [J. Phys. B 10 (1977) 3347] at low Z. The quadrupole oscillator strength sum Σ n f (2) gn is computed to be zero to a very high degree of precision. (atomic and molecular physics)
Quadrupole moments measured by nuclear orientation
International Nuclear Information System (INIS)
Bouchta, H.
1985-01-01
Quadrupole interactions between the nuclei and solids have been studied with the low temperature nuclear orientation technique. The first series of measurements have been effected on the orientation of 195H g m and 197 Hg m , long lived daughter states in the 195 Au and 197 Au decay. The lifetimes of these states are of the same order as the spin-lattice relaxation time. The reorientation of the intermediate states has been taken into account extending the dipole relaxation mechanism to non-equidistant relaxing substates. The experimental nuclear quadrupole moments, thus deduced are slightly different from theoretical estimations. A new high precision method accessible to levels with 100 ns to 1 m lifetimes, the level mixing resonance on oriented nuclei (LMR/ON) has been elaborated in collaboration with LEUVEN university (Belgium). In this technique the nucleus is subject to a non colinear electric plus magnetic combined interaction. The quadrupole interaction of Ag[7/2, = 40 s] isomer with the electric field gradient in zinc has been established to better than 1% observing its level mixing resonances; and also the ratio of electric field gradients of silver in zinc to cadmium. The electric quadrupole moments of 106 Ag m , 107 Ag m and 109 Ag m have been established combining the level mixing resonances with classical low temperature quadrupole alignment measurements. The experimental values are in good agreement with theoretical calculations based on a semi-microscopical model using Yukawa potential [fr
Precise calculations of the deuteron quadrupole moment
Energy Technology Data Exchange (ETDEWEB)
Gross, Franz L. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2016-06-01
Recently, two calculations of the deuteron quadrupole moment have have given predictions that agree with the measured value to within 1%, resolving a long-standing discrepancy. One of these uses the covariant spectator theory (CST) and the other chiral effective field theory (cEFT). In this talk I will first briefly review the foundations and history of the CST, and then compare these two calculations with emphasis on how the same physical processes are being described using very different language. The comparison of the two methods gives new insights into the dynamics of the low energy NN interaction.
Ground-state and pairing-vibrational bands with equal quadrupole collectivity in 124Xe
Radich, A. J.; Garrett, P. E.; Allmond, J. M.; Andreoiu, C.; Ball, G. C.; Bianco, L.; Bildstein, V.; Chagnon-Lessard, S.; Cross, D. S.; Demand, G. A.; Diaz Varela, A.; Dunlop, R.; Finlay, P.; Garnsworthy, A. B.; Hackman, G.; Hadinia, B.; Jigmeddorj, B.; Laffoley, A. T.; Leach, K. G.; Michetti-Wilson, J.; Orce, J. N.; Rajabali, M. M.; Rand, E. T.; Starosta, K.; Sumithrarachchi, C. S.; Svensson, C. E.; Triambak, S.; Wang, Z. M.; Wood, J. L.; Wong, J.; Williams, S. J.; Yates, S. W.
2015-04-01
The nuclear structure of 124Xe has been investigated via measurements of the β+/EC decay of 124Cs with the 8 π γ -ray spectrometer at the TRIUMF-ISAC facility. The data collected have enabled branching ratio measurements of weak, low-energy transitions from highly excited states, and the 2+→0+ in-band transitions have been observed. Combining these results with those from a previous Coulomb excitation study, B (E 2 ;23+→02+) =78 (13 ) W.u. and B (E 2 ;24+→03+) =53 (12 ) W.u. were determined. The 03+ state, in particular, is interpreted as the main fragment of the proton-pairing vibrational band identified in a previous 122Te (3He,n )124Xe measurement, and has quadrupole collectivity equal to, within uncertainty, that of the ground-state band.
Quadrupole moment and a proton halo structure in 17F (Iπ = 5/2+)
International Nuclear Information System (INIS)
Zhou Dongmei; Zheng Yongnan; Yuan Daqing; Xizhen, Zhang; Zuo Yi; Minamisono, T; Matsuta, M; Fukuda, M; Mihara, M; Zhang Chunlei; Zhiqiang, Wang; Du Enpeng; Luo Hailong; Xu Guoji; Zhu Shengyun
2007-01-01
The quadrupole moment of light nuclei 17 F in the ground state (I π = 5/2 + ) is measured by the β-NMR method. The effective charge of the last proton in a d 5/2 orbit for 17 F is extracted from the measured quadrupole moment Q( 17 F) divided by the quadrupole moment Q sp calculated with a single particle model. A proton effective charge of e eff p = 1.12 ± 0.07e is obtained, which is in agreement with that given by a particle-vibration coupling model calculation within the experimental error. The present value of the proton effective charge is strong evidence for the existence of a proton skin in 17 F (I π = 5/2 + )
Ab initio determination of the nuclear quadrupole moments of 114In, 115In, and 117In
International Nuclear Information System (INIS)
Errico, Leonardo A.; Renteria, Mario
2006-01-01
We present here ab initio determinations of the nuclear-quadrupole moment Q of hyperfine-probe-nuclear states of three different In isotopes: the 5 + 192 keV excited state of 114 In (probe for nuclear quadrupole alignment spectroscopy), the 9/2 + ground state of 115 In (nuclear magnetic and nuclear quadrupole resonance probe), and the 3/2 + 659 keV excited state of 117 In (perturbed angular correlations probe). These nuclear-quadrupole moments were determined by comparing experimental nuclear-quadrupole frequencies to the electric field gradient tensor calculated with high accuracy at In sites in metallic indium within the density functional theory. These ab initio calculations were performed with the full-potential linearized augmented plane wave method. The results obtained for the quadrupole moments of 114 In [Q( 114 In)=-0.14(1) b] are in clear discrepancy with those reported in the literature [Q( 114 In)=+0.16(6) b and +0.739(12) b]. For 115 In and 117 In our results are in excellent agreement with the literature and in the last case Q( 117 In) is determined with more precision. In the case of Q( 117 In), its sign cannot be determined because standard γ-γ perturbed angular correlations experiments are not sensitive to the sign of the nuclear-quadrupole frequency
Puzzle of the 6Li Quadrupole Moment: Steps toward Solving It
International Nuclear Information System (INIS)
Blokhintsev, L.D.; Kukulin, V.I.; Pomerantsev, V.N.
2005-01-01
The problem of the origin of the quadrupole deformation in the 6 Li ground state is investigated with allowance for the three-deuteron component of the 6 Li wave function. Two long-standing puzzles related to the tensor interaction in the 6 Li nucleus are known: that of an anomalous smallness of the 6 Li quadrupole moment (being negative, it is smaller in magnitude than the 7 Li quadrupole moment by a factor of 5) and that of an anomalous behavior of the tensor analyzing power T 2q in the scattering of polarized 6 Li nuclei on various targets. It is shown that a large (in magnitude) negative exchange contribution to the 6 Li quadrupole moment from the three-deuteron configuration cancels almost completely the 'direct' positive contribution due to the αd folding potential. As a result, the total quadrupole moment proves to be close to zero and highly sensitive to fine details of the tensor nucleon-nucleon interaction in the 4 He nucleus and of its wave function
Electric quadrupole moments of neutron-rich nuclei {sup 32}Al and {sup 31}Al
Energy Technology Data Exchange (ETDEWEB)
Kameda, D., E-mail: kameda@ribf.riken.jp; Ueno, H. [RIKEN Nishina Center (Japan); Asahi, K.; Nagae, D.; Takemura, M.; Shimada, K. [Tokyo Institute of Technology, Department of Physics (Japan); Yoshimi, A.; Nagatomo, T.; Sugimoto, T. [RIKEN Nishina Center (Japan); Uchida, M.; Arai, T.; Takase, K.; Suda, S.; Inoue, T. [Tokyo Institute of Technology, Department of Physics (Japan); Murata, J.; Kawamura, H. [Rikkyo University, Department of Physics (Japan); Watanabe, H. [Australian National University, Department of Nuclear Physics (Australia); Kobayashi, Y.; Ishihara, M. [RIKEN Nishina Center (Japan)
2007-11-15
The electric quadrupole moments for the ground states of {sup 32}Al and {sup 31}Al have been measured by the {beta} ray-detected nuclear quadrupole resonance method. Spin-polarized {sup 32}Al and {sup 31}Al nuclei were obtained from the fragmentation of {sup 40}Ar projectiles at E/A = 95 MeV/nucleon, and were implanted in a single crystal {alpha}-Al{sub 2}O{sub 3} stopper. The measured Q moment of {sup 32}Al, |Q({sup 32}Al)| = 24(2) mb, is in good agreement with a conventional shell-model calculation with a full sd model space and empirical effective charges, while that of {sup 31}Al is considerably smaller than the sd calculations.
The puzzle of the 6Li quadrupole moment: steps toward the solution
International Nuclear Information System (INIS)
Blokhintsev, L.D.; Kukulin, V.I.; Pomerantsev, V.N.
2005-01-01
The problem of origin of the ground-state 6 Li quadrupole deformation has been investigated with account of the three-deuteron component of this nucleus wave function. two long-standing puzzles related to the tensor interaction in 6 Li are known. The first one lies in the anomalously small value of the 6 Li quadrupole moment which, being negative, is in absolute magnitude smaller by the factor of 5 than that of 6 Li. The second puzzle consists in the anomalous behavior of the tensor analyzing power T 2q in scattering of polarized 6 Li nuclei from various targets. It is shown that the large (in absolute magnitude) negative contribution to the 6 Li quadrupole moment resulting from the three-deuteron configuration cancels almost completely the direct positive contribution due to the folding αd-potential. As a result, the total quadrupole moment turns out to be close to zero and highly sensitive to fine details of the tensor NN interaction and of the 4 He wave function [ru
Quadrupole moment of the superdeformed band in 131Ce
International Nuclear Information System (INIS)
He, Y.; Godfrey, M.J.; Jenkins, I.; Kirwan, A.J.; Nolan, P.J.
1990-01-01
A mean lifetime measurement has been carried out on the states in the superdeformed band found in 131 Ce using the Doppler shift attenuation method (DSAM). The measured intrinsic nuclear quadrupole moment is Q o approx= 6 eb, assuming constant deformation, which corresponds to a quadrupole deformation β 2 approx= 0.35. This is considerably smaller than the value deduced for 132 Ce. (author)
The ground state magnetic moment and susceptibility of a two electron Gaussian quantum dot
Boda, Aalu; Chatterjee, Ashok
2018-04-01
The problem of two interacting electrons moving in a two-dimensional semiconductor quantum dot with Gaussian confinement under the influence of an external magnetic field is studied by using a method of numerical diagonalization of the Hamiltonian matrix with in the effective-mass approximation. The energy spectrum is calculated as a function of the magnetic field. We find the ground state magnetic moment and the magnetic susceptibility show zero temperature diamagnetic peaks due to exchange induced singlet-triplet oscillations. The position and the number of these peaks depend on the size of the quantum dot and also strength of the electro-electron interaction. The theory is applied to a GaAs quantum dot.
Impurity quadrupole Kondo ground state in a dilute Pr system Y1-xPrxIr2Zn20
Yamane, Yu; Onimaru, Takahiro; Uenishi, Kazuto; Wakiya, Kazuhei; Matsumoto, Keisuke T.; Umeo, Kazunori; Takabatake, Toshiro
2018-05-01
The electrical resistivity ρ and specific heat C of a dilute Pr system Y1-xPrxIr2Zn20 for 0 ≤ x ≤ 0.44 were measured to study the phenomena arising from active quadrupoles of the Pr3+ ion with 4f2 configuration. On cooling, ρ's of all samples monotonically decrease, while the residual resistivity ratio ρ(300 K)/ρ(3 K) drastically decreases with x. In the whole range x ≤ 0.44, the magnetic contribution to the specific heat divided by temperature Cm/T shows a broad maximum at around 10 K, which can be reproduced by a two-level model with a first-excited triplet separated by 30 K from a ground state doublet. This indicates that the crystalline electric field ground state of the Pr ions remains in the Γ3 doublet for the cubic Td point group. On cooling, the Cm/T data for x = 0.085 and 0.44 approach constant values at Texpected from the random two-level model. By contrast, Cm/T for x = 0.044 increases continuously down to 0.08 K, suggesting a non-Fermi liquid state due to the impurity quadrupole Kondo effect.
Vingerhoets, P; Avgoulea, M; Billowes, J; Bissell, M L; Blaum, K; Brown, B A; Cheal, B; De Rydt, M; Forest, D H; Geppert, Ch; Honma, M; Kowalska, M; Kramer, J; Krieger, A; Mane, E; Neugart, R; Neyens, G; Nortershauser, W; Otsuka, T; Schug, M; Stroke, H H; Tungate, G; Yordanov, D T
2010-01-01
Measurements of the ground-state nuclear spins, magnetic and quadrupole moments of the copper isotopes from 61Cu up to 75Cu are reported. The experiments were performed at the ISOLDE facility, using the technique of collinear laser spectroscopy. The trend in the magnetic moments between the N=28 and N=50 shell closures is reasonably reproduced by large-scale shell-model calculations starting from a 56Ni core. The quadrupole moments reveal a strong polarization of the underlying Ni core when the neutron shell is opened, which is however strongly reduced at N=40 due to the parity change between the $pf$ and $g$ orbits. No enhanced core polarization is seen beyond N=40. Deviations between measured and calculated moments are attributed to the softness of the 56Ni core and weakening of the Z=28 and N=28 shell gaps.
Quadrupole moments of low-lying baryons with spin
Indian Academy of Sciences (India)
The chiral constituent quark model ( CQM) with general parametrization (GP) method has been formulated to calculate the quadrupole moments of the spin − 3 2 + decuplet baryons and spin − 3 2 + → 1 2 + transitions. The implications of such a model have been investigated in detail for the effects of symmetry breaking ...
Quadrupole moments of wobbling excitations in 163Lu
International Nuclear Information System (INIS)
Goergen, A.; Clark, R.M.; Cromaz, M.; Fallon, P.; Lee, I.Y.; Macchiavelli, A.O.; Ward, D.; Hagemann, G.B.; Sletten, G.; Huebel, H.; Bengtsson, R.
2004-01-01
Lifetimes of states in the triaxial strongly deformed bands of 163 Lu have been measured with the Gammasphere spectrometer using the Doppler-shift attenuation method. The bands have been interpreted as wobbling-phonon excitations from the characteristic electromagnetic properties of the transitions connecting the bands. Quadrupole moments are extracted for the zero-phonon yrast band and, for the first time, for the one-phonon wobbling band. The very similar results found for the two bands suggest a similar intrinsic structure and support the wobbling interpretation. While the in-band quadrupole moments for the bands show a decreasing trend towards higher spin, the ratio of the interband to the in-band transition strengths remains constant. Both features can be understood by a small increase in triaxiality towards higher spin. Such a change in triaxiality is also found in cranking calculations, to which the experimental results are compared
Reorientation precession measurements of quadrupole moments in 103Rh
International Nuclear Information System (INIS)
Gelberg, A.; Herskind, B.; Kalish, R.; Neiman, M.
1976-01-01
The quadrupole moments of the 3/2 - and 5/2 - states in 103 Rh have been determined by measuring the precession of the gamma-ray angular distribution following Coulomb excitation; 16 O and 32 S beams have been used. The structure of the negative-parity states in 103 Rh is found to be in agreement with the model of Arima and Iachello. (orig.) [de
Static quadrupole moment of the Kπ = 14+ isomer in 176W
International Nuclear Information System (INIS)
Ionescu-Bujor, M.; Iordachescu, A.; Bucurescu, D.; Brandolini, F.; Lenzi, S. M.; Pavan, P.; Rossi Alvarez, C.; Marginean, N.; Medina, N.H.; Ribas, R.V.; De Poli, M.; Napoli, D. R.; Podolyak, Zs.; Ur, C. A.
2001-01-01
The investigation of high-K isomeric states in the deformed nuclei of the A∼180 region has found renewed interest in recent years. Much experimental and theoretical work was devoted to understand the mechanisms which govern their decay to lower-lying states, particularly the anomalous strong decays to low-K states. Other questions of great importance are the quenching of the pairing correlations and the shape polarization effects in the high-seniority multi-quasiparticle excitations. Our interest focused on the 41 ns K π =14 + 3746 keV isomeric state with anomalous decay in 176 W. On the basis of a precise g-factor measurement we assigned to this isomer a pure four-quasiparticle configuration, composed by two protons in the 7/2 + [404] and 9/2 - [514] orbitals and two neutrons in the 7/2 + [633] and 5/2 - [512] orbitals. In the present work the measurement of its static quadrupole moment has been performed. Prior to our experiment, static quadrupole moments have been measured only for three high-K isomeric states of seniority ≥ 4 in the A∼180 region: 16 + in 178 Hf, 35/2 - in 179 W and 25 + in 182 Os. A deformation very similar to that of the ground state has been deduced for the 16 + isomer in 178 Hf, while for the high-K isomers in 179 W and 182 Os significantly smaller deformations were reported. The quadrupole interaction of the 14 + isomeric state in 176 W has been investigated in the electric field gradient (EFG) of the polycrystalline lattice of metallic Tl by applying the time-differential perturbed angular distribution method. For W impurities in Tl host the EFG strength and its temperature dependence have been recently reported. The isomer was populated in the 164 Dy( 16 O,4n) 176 W reaction using a 83 MeV 16 O pulsed beam (pulse width 1.5 ns, repetition period 800 ns) delivered by the XTU-Tandem of Laboratori Nazionali di Legnaro. The target consisted of 0.5 mg/cm 2 metallic 164 Dy on thick Tl backing in which both the recoiling 176 W nuclei and
Extracting the Omega- electric quadrupole moment from lattice QCD data
Energy Technology Data Exchange (ETDEWEB)
G. Ramalho, M.T. Pena
2011-03-01
The Omega- has an extremely long lifetime, and is the most stable of the baryons with spin 3/2. Therefore the Omega- magnetic moment is very accurately known. Nevertheless, its electric quadrupole moment was never measured, although estimates exist in different formalisms. In principle, lattice QCD simulations provide at present the most appropriate way to estimate the Omega- form factors, as function of the square of the transferred four-momentum, Q2, since it describes baryon systems at the physical mass for the strange quark. However, lattice QCD form factors, and in particular GE2, are determined at finite Q2 only, and the extraction of the electric quadrupole moment, Q_Omega= GE2(0) e/(2 M_Omega), involves an extrapolation of the numerical lattice results. In this work we reproduce the lattice QCD data with a covariant spectator quark model for Omega- which includes a mixture of S and two D states for the relative quark-diquark motion. Once the model is calibrated, it is used to determine Q_Omega. Our prediction is Q_Omega= (0.96 +/- 0.02)*10^(-2) efm2 [GE2(0)=0.680 +/- 0.012].
International Nuclear Information System (INIS)
Steffen, R.M.
1982-10-01
Until June 1982 all muonic x-ray experiments were performed at the Stopped Muon Channel (SMC) in experimental area A of LAMPF. The SMC channel, consisting of 3 bending magnets and 21 quadrupole magnets, is specifically designed for a clean muon beam and incorporates a long path for the decay of the pions. Recently a number of long-time experiments (rare decay modes of the muon, etc.) have been assigned to the SMC and running time for the muonic x-ray experiments has become very precious. For these reasons considerable time was spent in the summer of 1982 to study the feasibility of doing muonic experiments at the abandoned Biomed channel which has been designed for pion-irradiation therapy of cancer patients. Since the length of the Biomed channel is short, the available experimental area is close to the production target, and hence the neutron background in the experimental area is intolerably large (about 50 times larger than in the SMC experimental area). To reduce this background, the muonic x-ray detector and counter telescope arrangement was modified and surrounded by a concrete and steel shielding house of 1.5 feet minimum wall thickness. The dimensions of the house were 10' x 14' x 6' (H). The background was thus reduced to an acceptable level, even though the signal-to-noise ratio is still twice as large as in the SMC. Nevertheless, the Biomed channel is now usable for Muonic x-ray experiments that do not involve the observation of muonic x-rays of less than 0.5 MeV energy. The muonic x-ray experiments on 233 U described in this Progress Report have been performed at the Biomed channel
The quadrupole moments of Cd and Zn isotopes - an apology
Haas, H.; Barbosa, M. B.; Correia, J. G.
2016-12-01
In 2010 we presented an update of the nuclear quadrupole moments (Q) for the Cd and Zn isotopes, based essentially on straightforward density functional (DF) calculations (H. Haas and J.G. Correia, Hyperfine Interact 198, 133-137 (2010)). It has been apparent for some years that the standard DF procedure obviously fails, however, to reproduce the known electric-field gradient (EFG) for various systems, typical cases being Cu2O, As and Sb, and the solid halogens. Recently a cure for this deficiency has been found in the hybrid DF technique. This method is now applied to solid Cd and Zn, and the resultant quadrupole moments are about 15 % smaller than in our earlier report. Also nuclear systematics, using the recently revised values of Q for the long-lived 11/2 isomers in111Cd to129Cd, together with earlier PAD data for107,109Cd, leads to the same conclusion. In addition, EFG calculations for the cadmium dimethyl molecule further support the new values: Q(111Cd, 5/2+) = .683(20) b, Q(67Zn, gs) = .132(5) b. This implies, that the value for the atomic EFG in the 3it {P}1 state of Zn must be revised, as it has been for Cd.
Transition quadrupole moments in the superdeformed band of 40Ca
International Nuclear Information System (INIS)
Chiara, C.J.; Ideguchi, E.; Devlin, M.; LaFosse, D.R.; Lerma, F.; Reviol, W.; Ryu, S.K.; Sarantites, D.G.; Baktash, C.; Galindo-Uribarri, A.; Carpenter, M.P.; Janssens, R.V.F.; Lauritsen, T.; Lister, C.J.; Reiter, P.; Seweryniak, D.; Fallon, P.; Goergen, A.; Macchiavelli, A.O.; Rudolph, D.
2003-01-01
The transition quadrupole moments Q t for the superdeformed band in 40 Ca have been determined through thin-target Doppler-shift attenuation analyses. A best-fit value of Q t =1.30±0.05 e b is obtained when a single value is assumed for the entire band. Fitting separate quadrupole moments for in-band transitions decaying from the high-spin states and the presumably admixed low-spin states results in Q t (high)=1.81 -0.26 +0.41 e b and Q t (low)=1.18 -0.05 +0.06 e b, respectively. Q t values extracted for individual transitions in a Doppler-broadened line-shape analysis also indicate smaller Q t values at lower spins. These results are consistent with the interpretation of this band as an eight-particle-eight-hole superdeformed band with a significant admixture of less-collective configurations at low spins
Sensitivity of (α,α') cross sections to excited-state quadrupole moments
International Nuclear Information System (INIS)
Baker, F.T.; Scott, A.; Ronningen, R.M.; Hamilton, J.H.; Kruse, T.H.; Suchannek, R.; Savin, W.
1977-01-01
Inelastic α particle scattering at 21 and 24 MeV has been used to estimate the electric quadrupole moment of the second 2 + state in 180 Hf. Sensitivity to the assumed quadrupole moment is due almost entirely to reorientation via the nuclear force. Results suggest that the technique may be a useful method of estimating excited state quadrupole moments, particularly for states with high excitation energies or with J greater than 2
Does the small CMB quadrupole moment suggest new physics?
Cline, J M; Lesgourgues, Julien; Cline, James M.; Crotty, Patrick; Lesgourgues, Julien
2003-01-01
Motivated by WMAP's confirmation of an anomalously low value of the quadrupole moment of the CMB temperature fluctuations, we investigate the effects on the CMB of cutting off the primordial power spectrum P(k) at low wave numbers. This could arise, for example, from a break in the inflaton potential, a prior period of matter or radiation domination, or an oscillating scalar field which couples to the inflaton. We reanalyze the full WMAP parameter space supplemented by a low-k cutoff for P(k). The temperature correlations by themselves are better fit by a cutoff spectrum, but including the TE temperature-polarization spectrum reduces this preference to a 1.4 sigma effect. Inclusion of large scale structure data does not change the conclusion. If taken seriously, the low-k cutoff is correlated with optical depth so that reionization occurs even earlier than indicated by the WMAP analysis.
International Nuclear Information System (INIS)
Guerout, R.; Aymar, M.; Dulieu, O.
2010-01-01
In this study, we investigate the structure of the polar alkali-metal-atom-strontium diatomic molecules as possible candidates for the realization of samples of ultracold polar molecular species not yet investigated experimentally. Using a quantum chemistry approach based on effective core potentials and core polarization potentials, we model these systems as effective three-valence-electron systems, allowing for calculation of electronic properties with full configuration interaction. The potential curve and the permanent dipole moment of the 2 Σ + ground state are determined as functions of the internuclear distance for LiSr, NaSr, KSr, RbSr, and CsSr molecules. These molecules are found to exhibit a significant permanent dipole moment, though smaller than those of the alkali-metal-atom-Rb molecules.
Electric dipole moment function and line intensities for the ground state of carbon monxide
International Nuclear Information System (INIS)
Chen Hua-Jun; Cheng Xin-Lu; Wu Jie; Liu Hao
2015-01-01
An accurate electric dipole moment function (EDMF) is obtained for the carbon monoxide (CO) molecule (X 1 Σ + ) by fitting the experimental rovibrational transitional moments. Additionally, an accurate ab initio EDMF is found using the highly accurate, multi-reference averaged coupled-pair functional (ACPF) approach with the basis set, aug-cc-pV6Z, and a finite-field with ±0.005 a.u. (The unit a.u. is the abbreviation of atomic unit). This ab initio EDMF is very consistent with the fitted ones. The vibrational transition matrix moments and the Herman–Wallis factors, calculated with the Rydberg–Klein–Rees (RKR) potential and the fitted and ab initio EDMFs, are compared with experimental measurements. The consistency of these line intensities with the high-resolution transmission (HITRAN) molecular database demonstrates the improved accuracy of the fitted and ab initio EDMFs derived in this work. (paper)
Quadrupole moment in the excited 2Psub(1/2) state
International Nuclear Information System (INIS)
Amusia, M.Ya.; Yakhontov, V.L.
1984-01-01
Computation of the quadrupole moment values in the 2Psub(1/2) states of hydrogen and meso-hydrogen is carried out. It is shown that allowance for the hyperfine interaction of the electron with the proton in the first order of perturbation theory results in giant values of the quadrupole moment of the atoms. (author)
International Nuclear Information System (INIS)
Dracoulis, G.D.
1978-11-01
The recrossing of the ground state band with the super band as an explanation for the second anomaly in 158 Er is examined in terms of the moment of inertia. A two band mixing calculation does not reproduce the experimenal moment of inertia curve
Quadrupole moments as measures of electron correlation in two-electron atoms
International Nuclear Information System (INIS)
Ceraulo, S.C.; Berry, R.S.
1991-01-01
We have calculated quadrupole moments, Q zz , of helium in several of its doubly excited states and in two of its singly excited Rydberg states, and of the alkaline-earth atoms Be, Mg, Ca, Sr, and Ba in their ground and low-lying excited states. The calculations use well-converged, frozen-core configuration-interaction (CI) wave functions and, for interpretive purposes, Hartree-Fock (HF) atomic wave functions and single-term, optimized, molecular rotor-vibrator (RV) wave functions. The quadrupole moments calculated using RV wave functions serve as a test of the validity of the correlated, moleculelike model, which has been used to describe the effects of electron correlation in these two-electron and pseudo-two-electron atoms. Likewise, the quadrupole moments calculated with HF wave functions test the validity of the independent-particle model. In addition to their predictive use and their application to testing simple models, the quadrupole moments calculated with CI wave functions reveal previously unavailable information about the electronic structure of these atoms. Experimental methods by which these quadrupole moments might be measured are also discussed. The quadrupole moments computed from CI wave functions are presented as predictions; measurements of Q zz have been made for only two singly excited Rydberg states of He, and a value of Q zz has been computed previously for only one of the states reported here. We present these results in the hope of stimulating others to measure some of these quadrupole moments
The electric dipole moments in the ground states of gold oxide, AuO, and gold sulfide, AuS.
Zhang, Ruohan; Yu, Yuanqin; Steimle, Timothy C; Cheng, Lan
2017-02-14
The B 2 Σ - - X 2 Π 3/2 (0,0) bands of a cold molecular beam sample of gold monoxide, AuO, and gold monosulfide, AuS, have been recorded at high resolution both field free and in the presence of a static electric field. The observed electric field induced splittings and shifts were analyzed to produce permanent electric dipole moments, μ→ el , of 2.94±0.06 D and 2.22±0.05 D for the X 2 Π 3/2 (v = 0) states of AuO and AuS, respectively. A molecular orbital correlation diagram is used to rationalize the trend in ground state μ→ el values for AuX (X = F, Cl, O, and S) molecules. The experimentally determined μ→ el are compared to those computed at the coupled-cluster singles and doubles (CCSD) level augmented with a perturbative inclusion of triple excitations (CCSD(T)) level of theory.
Energy Technology Data Exchange (ETDEWEB)
Kellö, Vladimir [Department of Physical Chemistry, Comenius University, SK-842 15 Bratislava (Slovakia)
2015-01-22
Highly correlated scalar relativistic calculations of electric field gradients at nuclei in diatomic molecules in combination with accurate nuclear quadrupole coupling constants obtained from microwave spectroscopy are used for determination of nuclear quadrupole moments.
Bandyopadhyay, Debades; Bhat, Sajad A.; Char, Prasanta; Chatterjee, Debarati
2018-02-01
We investigate the impact of strange-matter equations of state involving Λ hyperons, Bose-Einstein condensate of K- mesons and first-order hadron-quark phase transition on moment of inertia, quadrupole moment and tidal deformability parameter of slowly rotating neutron stars. All these equations of state are compatible with the 2 M_{solar} constraint. The main findings of this investigation are the universality of the I- Q and I -Love number relations, which are preserved by the EoSs including Λ hyperons and antikaon condensates, but broken in the presence of a first-order hadron-quark phase transition. Furthermore, it is also noted that the quadrupole moment approaches the Kerr value of a black hole for maximum-mass neutron stars.
Electric quadrupole moments of {beta}-emitter {sup 21}F and {sup 23}Mg
Energy Technology Data Exchange (ETDEWEB)
Onishi, Takashi; Matsuta, Kensaku; Fukuda, Mitsunori [Osaka Univ., Toyonaka (Japan). Faculty of Science] [and others
1997-03-01
For the systematic study of nuclear electromagnetic moments, electric quadrupole moments Q of {beta}-emitting nuclei {sup 21}F and {sup 23}Mg have been measured for the first time through combined technique of the polarized nuclear beams and {beta}-NMR technique. From the quadrupole coupling constants of {sup 21}F and {sup 23}Mg in MgF{sub 2} single crystal, the ratios of the Q`s with the known Q were determined as |Q({sup 21}F)|/|Q({sup 19}F{sup *})|=1.001{+-}0.034 and |Q({sup 23}Mg)|/|Q({sup 25}Mg)|=0.571{+-}0.017. (author)
Static quadrupole moment of the first excited state of 24Mg
International Nuclear Information System (INIS)
Fewell, M.P.; Hinds, S.; Kean, D.C.; Zabel, T.H.
1979-01-01
The static quadrupole moment Qsub(2+) and the B(E2;0 + → 2 + ) value for the first excited state of 24 Mg have been determined using the reorientation effect in Coulomb excitation. Surface barrier detectors at 90 0 and 172 0 were used to detect 24 Mg ions scattered from 208 Pb. It is found that Qsub(2+) = -18.1 +- 1.3 e.fm 2 , suggesting that, contrary to most previous experimental evidence, the quadrupole moment is in agreement with theoretical predictions. For B(E2;0 + → 2 + ) the value 443 +- 24 e 2 . fm 4 was obtained
Hyperfine structure in the Gd II spectrum and the nuclear electric quadrupole moment of 157Gd
International Nuclear Information System (INIS)
Clieves, H.P.; Steudel, A.
1979-01-01
The hyperfine structure of 157 Gd was investigated in 20 Gd II lines by means of a photoelectric recording Fabry-Perot interferometer with digital data processing. The hyperfine splitting factors, A and B, were obtained by computer fits to the observed line structures. Using a multiconfigurational set of wave functions in intermediate coupling derived by Wyart, mono-electronic parameters were deduced by a parametric treatment. The nuclear electric quadrupole moment of 157 Gd was evaluated from the quadrupole interaction of the 5d electron in 4f 7 5d6s, the 5d electron in 4f 7 5d6p, and the 6p electron in 4f 7 5d6p. The three values obtained for the quadrupole moment agree very well. The final result, corrected for Sternheimer shielding, is Q( 157 Gd) = 1.34(7) x 10 -24 cm 2 . (orig.) [de
Energy Technology Data Exchange (ETDEWEB)
Stone, N. J., E-mail: n.stone@physics.ox.ac.uk [Department of Physics and Astronomy, University of Tennessee, Knoxville Tennessee 37996 (United States)
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.
Erratum to: Quadrupole moments of low-lying baryons with spin ...
Indian Academy of Sciences (India)
physics pp. 1083. Erratum to: Quadrupole moments of low-lying baryons with spin-. 1. 2. +. , spin-. 3. 2. +. , and spin-. 3. 2. +. → 1. 2. + transitions. NEETIKA SHARMA and HARLEEN DAHIYA. ∗. Department of Physics, Dr. B.R. Ambedkar National Institute of Technology,. Jalandhar 144 011, India. ∗. Corresponding author.
Spin, quadrupole moment, and deformation of the magnetic-rotational band head in Pb193
Balabanski, D. L.; Ionescu-Bujor, M.; Iordachescu, A.; Bazzacco, D.; Brandolini, F.; Bucurescu, D.; Chmel, S.; Danchev, M.; de Poli, M.; Georgiev, G.; Haas, H.; Hübel, H.; Marginean, N.; Menegazzo, R.; Neyens, G.; Pavan, P.; Rossi Alvarez, C.; Ur, C. A.; Vyvey, K.; Frauendorf, S.
2011-01-01
The spectroscopic quadrupole moment of the T1/2=9.4(5) ns isomer in Pb193 at an excitation energy Eex=(2585+x) keV is measured by the time-differential perturbed angular distribution method as |Qs|=2.6(3) e b. Spin and parity Iπ=27/2- are assigned to it based on angular distribution measurements. This state is the band head of a magnetic-rotational band, described by the 1i13/2 subshell with the (3s1/2-21h9/21i13/2)11- proton excitation. The pairing-plus-quadrupole tilted-axis cranking calculations reproduce the measured quadrupole moment with a moderate oblate deformation ɛ2=-0.11, similar to that of the 11-proton intruder states, which nuclei in the region. This is the first direct measurement of a quadrupole moment and thus of the deformation of a magnetic-rotational band head.
Spin, quadrupole moment, and deformation of the magnetic-rotational band head in (193)Pb
Balabanski, D L; Iordachescu, A; Bazzacco, D; Brandolini, F; Bucurescu, D; Chmel, S; Danchev, M; De Poli, M; Georgiev, G; Haas, H; Hubel, H; Marginean, N; Menegazzo, R; Neyens, G; Pavan, P; Rossi Alvarez, C; Ur, C A; Vyvey, K; Frauendorf, S
2011-01-01
The spectroscopic quadrupole moment of the T(1/2) = 9.4(5) ns isomer in (193)Pb at an excitation energy E(ex) = (2585 + x) keV is measured by the time-differential perturbed angular distribution method as vertical bar Q(s)vertical bar = 2.6(3) e b. Spin and parity I(pi) = 27/2(-) are assigned to it based on angular distribution measurements. This state is the band head of a magnetic-rotational band, described by the coupling of a neutron hole in the 1i(13/2) subshell with the (3s(1/2)(-2)1h(9/2)1i(13/2))(11-) proton excitation. The pairing-plus-quadrupole tilted-axis cranking calculations reproduce the measured quadrupole moment with a moderate oblate deformation epsilon(2) = -0.11, similar to that of the 11(-)proton intruder states, which occur in the even-even Pb nuclei in the region. This is the first direct measurement of a quadrupole moment and thus of the deformation of a magnetic-rotational band head.
Determination of the effective quadrupole moment in $^{181}$Ta with pionic x-rays
Beetz, R; Fransson, K; Konijn, J; Panman, J; Tauscher, Ludwig; Tibell, G
1978-01-01
From the hyperfine splitting of the 5g to 4f and the 6g to 4f pionic X-rays in /sup 181/Ta, an effective quadrupole moment of Q/sub eff /=3.58+or-0.03 b was determined. The strong interaction monopole shift epsilon /sub 0/ and the width Gamma /sub 0/ of the 4f level were measured to be epsilon /sub 0/=540+or-100 eV and Gamma /sub 0 /=225+or-57 eV, in good agreement with the values obtained with the standard optical potential description of the pion-nucleus interaction. Estimating the influence of the finite nuclear size, the deformation induced through the strong interaction between the pion and the finite nucleus, and the relative magnitude between the strong and the electromagnetic quadrupole coupling constants values for the spectroscopic quadrupole moment of Q=3.30+or-0.06 b, and for the intrinsic quadrupole moment of Q/sub 0/=7.06+or-0.12 b are obtained. (28 refs).
Quadrupole moments of the 12+ isomers in 188Hg and 190Hg
International Nuclear Information System (INIS)
Dracoulis, G.D.; Lonnroth, T.; Vajda, S.; Dafni, E.; Schatz, G.
1984-01-01
The electric quadrupole interaction of the 12 + isomers in 188 Hg and 190 Hg has been measured in solid Hg. The quadrupole moments deduced, vertical strokeQ[ 188 Hg(12 + )]vertical stroke = 91(11) e fm 2 and vertical strokeQ[ 190 Hg(12 + )]vertical stroke = 117(14) e fm 2 suggest a possible change in γ-deformation due to the rotation alignment of the isub(13/2) quasi-neutrons. The temperature dependence of the electric field gradient tensor in Hg was also determined. (orig.)
Directory of Open Access Journals (Sweden)
Andrzej Magiera
2017-09-01
Full Text Available Measurements of electric dipole moment (EDM for light hadrons with use of a storage ring have been proposed. The expected effect is very small, therefore various subtle effects need to be considered. In particular, interaction of particle’s magnetic dipole moment and electric quadrupole moment with electromagnetic field gradients can produce an effect of a similar order of magnitude as that expected for EDM. This paper describes a very promising method employing an rf Wien filter, allowing to disentangle that contribution from the genuine EDM effect. It is shown that both these effects could be separated by the proper setting of the rf Wien filter frequency and phase. In the EDM measurement the magnitude of systematic uncertainties plays a key role and they should be under strict control. It is shown that particles’ interaction with field gradients offers also the possibility to estimate global systematic uncertainties with the precision necessary for an EDM measurement with the planned accuracy.
Magiera, Andrzej
2017-09-01
Measurements of electric dipole moment (EDM) for light hadrons with use of a storage ring have been proposed. The expected effect is very small, therefore various subtle effects need to be considered. In particular, interaction of particle's magnetic dipole moment and electric quadrupole moment with electromagnetic field gradients can produce an effect of a similar order of magnitude as that expected for EDM. This paper describes a very promising method employing an rf Wien filter, allowing to disentangle that contribution from the genuine EDM effect. It is shown that both these effects could be separated by the proper setting of the rf Wien filter frequency and phase. In the EDM measurement the magnitude of systematic uncertainties plays a key role and they should be under strict control. It is shown that particles' interaction with field gradients offers also the possibility to estimate global systematic uncertainties with the precision necessary for an EDM measurement with the planned accuracy.
Quadrupole moments of odd-A 53−63Mn: Onset of collectivity towards N=40
Directory of Open Access Journals (Sweden)
C. Babcock
2016-09-01
Full Text Available The spectroscopic quadrupole moments of the odd–even Mn isotopes between N=28 and N=38 have been measured using bunched-beam collinear laser spectroscopy at ISOLDE, CERN. In order to increase sensitivity to the quadrupole interaction, the measurements have been done using a transition in the ion rather than in the atom, with the additional advantage of better spectroscopic efficiency. Since the chosen transition is from a metastable state, optical pumping in ISOLDE's cooler and buncher (ISCOOL was used to populate this state. The extracted quadrupole moments are compared to large-scale shell model predictions using three effective interactions, GXPF1A, LNPS and modified A3DA. The inclusion of both the 1νg9/2 and 2νd5/2 orbitals in the model space is shown to be necessary to reproduce the observed increase in the quadrupole deformation from N=36 onwards. Specifically, the inclusion of the 2νd5/2 orbital induces an increase in neutron and proton excitations across the reduced gaps at N=40 and Z=28, leading to an increase in deformation above N=36.
The quadrupole moment of the first 3- state in 208Pb
International Nuclear Information System (INIS)
Joye, A.M.R.; Baxter, A.M.; Fewell, M.P.; Kean, D.C.; Spear, R.H.
1977-04-01
The B(E3; 0 + →3 - ) and quadrupole moment, Qsub(3 - ), of the first excited state of 208 Pb have been measured by the reorientation effect in Coulomb excitation, giving B(E3; 0 + →3 - ) = 0.665 +- E 2 B 3 and Qsub(3 - ) = -0.42 +- 0.32 EB. This value for Qsub(3 - ) is much smaller in magnitude than those obtained by Barnett et al., and is consistent with most theoretical predictions. (Author)
The charge form factor, the quadrupole moment and the photodisintegration of 6Li
International Nuclear Information System (INIS)
Susila, S.; Srinivasa Rao, K.
1981-01-01
The root mean square radius, the charge form factor, the charge density, the quadrupole moment and the bremsstrahlung weighted cross section for the photodisintegration of 6 Li, are calculated using a polarised cluster model wave function, which is modified to take into account, in its relative motion part, the requirement of a shell model node. A set of parameters, in the modified cluster model wave function, which account for the available experimental data for the afore-said quantities, is determined. (author)
Rotating effects on the Landau quantization for an atom with a magnetic quadrupole moment
Energy Technology Data Exchange (ETDEWEB)
Fonseca, I. C.; Bakke, K., E-mail: kbakke@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, João Pessoa, PB 58051-970 (Brazil)
2016-01-07
Based on the single particle approximation [Dmitriev et al., Phys. Rev. C 50, 2358 (1994) and C.-C. Chen, Phys. Rev. A 51, 2611 (1995)], the Landau quantization associated with an atom with a magnetic quadrupole moment is introduced, and then, rotating effects on this analogue of the Landau quantization is investigated. It is shown that rotating effects can modify the cyclotron frequency and breaks the degeneracy of the analogue of the Landau levels.
Rotating effects on the Landau quantization for an atom with a magnetic quadrupole moment
Fonseca, I. C.; Bakke, K.
2016-01-01
Based on the single particle approximation [Dmitriev et al., Phys. Rev. C 50, 2358 (1994) and C.-C. Chen, Phys. Rev. A 51, 2611 (1995)], the Landau quantization associated with an atom with a magnetic quadrupole moment is introduced, and then, rotating effects on this analogue of the Landau quantization is investigated. It is shown that rotating effects can modify the cyclotron frequency and breaks the degeneracy of the analogue of the Landau levels.
Rotating effects on the Landau quantization for an atom with a magnetic quadrupole moment
International Nuclear Information System (INIS)
Fonseca, I. C.; Bakke, K.
2016-01-01
Based on the single particle approximation [Dmitriev et al., Phys. Rev. C 50, 2358 (1994) and C.-C. Chen, Phys. Rev. A 51, 2611 (1995)], the Landau quantization associated with an atom with a magnetic quadrupole moment is introduced, and then, rotating effects on this analogue of the Landau quantization is investigated. It is shown that rotating effects can modify the cyclotron frequency and breaks the degeneracy of the analogue of the Landau levels
Energy Technology Data Exchange (ETDEWEB)
Yurchenko, Sergei N. [Technische Universitaet Dresden, Institut fuer Physikalische Chemie und Elektrochemie, D-01062 Dresden (Germany); Thiel, Walter [Max-Planck-Institut fuer Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Muelheim an der Ruhr (Germany); Carvajal, Miguel [Departamento de Fisica Aplicada, Facultad de Ciencias Experimentales, Avenida de las Fuerzas Armadas s/n, Universidad de Huelva, E-21071 Huelva (Spain); Jensen, Per [Theoretische Chemie, Bergische Universitaet, D-42097 Wuppertal (Germany)], E-mail: jensen@uni-wuppertal.de
2008-05-04
We report the calculation of a six-dimensional CCSD(T)/aug-cc-pVQZ potential energy surface for the electronic ground state of NH{sub 3}{sup +} together with the corresponding CCSD(T)/aug-cc-pVTZ dipole moment and polarizability surface of {sup 14}NH{sub 3}{sup +}. These electronic properties have been computed on a large grid of molecular geometries. A number of newly calculated band centers are presented along with the associated electric-dipole transition moments. We further report the first calculation of vibrational matrix elements of the polarizability tensor components for {sup 14}NH{sub 3}{sup +}; these matrix elements determine the intensities of Raman transitions. In addition, the rovibrational absorption spectra of the {nu}{sub 2}, {nu}{sub 3}, {nu}{sub 4}, 2{nu}{sub 2}-{nu}{sub 2}, and {nu}{sub 2}+{nu}{sub 3}-{nu}{sub 2} bands have been simulated.
Quadrupole Moments And Gamma Deformation Of Wobbling Excitations In 163Ln
International Nuclear Information System (INIS)
Goergen, A.; Hagemann, G.B.; Sletten, G.; Hamamoto, I.; Bengtsson, R.; Clark, R.M.; Cromaz, M.; Fallon, P.; Lee, I.Y.; Macchiavelli, A.O.; Ward, D.; Huebel, H.
2005-01-01
Wobbling is an excitation mode unique to triaxial nuclei. Even though it is a general consequence of triaxiality in nuclei, it has so far only been observed in the odd-mass Lu isotopes around 163Lu. The principal evidence for the wobbling mode is based on the pattern of rotational bands characterized and described by a wobbling phonon number and the decay between different bands belonging to the same family. A new measurement revealed lifetimes of states in an excited wobbling band for the first time and gave access to absolute transition probabilities for both in-band and interband transitions. A general recipe how to derive quadrupole moments for triaxial nuclei from experimental data is discussed. The results show a remarkable similarity of the quadrupole moments for the different bands, further supporting the wobbling scenario. A decrease of the quadrupole moments is observed with increasing spin. This is attributed to an increase in triaxiality with spin, which can at the same time explain the dependence of the interband transitions on spin. Such an increase in triaxiality is qualitatively reproduced by cranking calculations to which the experimental results are compared
International Nuclear Information System (INIS)
Tanaka, K.; Nakahara, Y.; Yamaguchi, M.; Tanaka, T.
1987-01-01
The method of CO 2 -laser-microwave double resonance (LMDR) with an intense electric field was used to measure Stark shifts of ground-state microwave transitions of D 2 CO. Thirty LMDR signals originating from 15 K-doublet transitions were observed, associated with the infrared transitions of the ν 4 and ν 6 bands. Least-squares analysis of the observed LMDR signals yields precise values of the coefficients in the dipole-moment expansion, μ 0 +μ/sub J/ J(J+1)+μ/sub K/ K 2 : μ 0 , 2.347 134(8) D; μ/sub j/, -4.76(10) x 10 -6 D; μ/sub K/, -28.7(18) x 10 -6 D; where one-standard-deviation uncertainties are given in parentheses. The infrared--infrared double-resonance signals of PH 3 , which were calibrated against the OCS dipole moment, were used for the electric-field calibration, allowing us to determine the dipole moment with a precision of 10 parts in 10 6 (ppm). However, the absolute accuracy of the dipole moment obtained is 50 ppm, as limited by the uncertainty of the OCS dipole moment. The effective dipole moment for the 1/sub 1.0/ reverse arrow 1/sub 1.1/ transition measured in the present study agrees well with the effective dipole moment for the 1/sub 1.0/ rotational level from a molecular-beam electric resonance experiment. The μ/sub J/ and μ/sub K/ coefficients calculated from Watson's θ/sub γ//sup α//sup β/ constants agree well with the experimental values
International Nuclear Information System (INIS)
Denton, Peter B.; Weiler, Thomas J.
2015-01-01
Determining anisotropies in the arrival directions of cosmic rays at the highest energy is an important task in astrophysics. It is common and useful to partition the sky into spherical harmonics as a measure of anisotropy. The two lowest nontrivial spherical harmonics, the dipole and the quadrupole, are of particular interest, since these distributions encapsulate a dominant single source and a plane of sources, as well as offering relatively high statistics. The best experiments for the detection of ultra high energy cosmic rays currently are all ground-based, with highly nonuniform exposures on the sky resulting from the fixed experimental locations on the Earth. This nonuniform exposure increases the complexity and error in inferring anisotropies. It turns out that there is an optimal latitude for an experiment at which nonuniform exposure does not diminish the inference of the quadrupole moment. We derive the optimal latitude and find that (presumably by a fortuitous coincidence) this optimal latitude runs through the largest cosmic ray experiment, the Pierre Auger Observatory (PAO) in the Southern Hemisphere, and close to the largest cosmic ray experiment in the Northern Hemisphere, the Telescope Array (TA). Consequently, assuming a quadrupole distribution, PAO and TA can reconstruct the cosmic ray quadrupole distribution to a high precision without concern for their partial sky exposure
Ground state properties of exotic nuclei in deformed medium mass region
International Nuclear Information System (INIS)
Manju; Chatterjee, R.; Singh, Jagjit; Shubhchintak
2017-01-01
The dipole moment, size of the nucleus and other ground state properties of deformed nuclei 37 Mg and 31 Ne are presented. Furthermore with this deformed wave function the electric dipole strength distribution for deformed nuclei 37 Mg and 31 Ne is calculated. This will allow us to investigate the two dimensional scaling phenomenon with two parameters: quadrupole deformation and separation energy
Patterns of the ground states in the presence of random interactions : Nucleon systems
Zhao, YM; Arima, A; Shimizu, N; Ogawa, K; Yoshinaga, N; Scholten, O
We present our results on properties of ground states for nucleonic systems in the presence of random two-body interactions. In particular, we calculate probability distributions for parity, seniority, spectroscopic (i.e., in the laboratory frame) quadrupole moments, and discuss a clustering in the
Hurst, A M
2007-01-01
Using a method whereby molecular and atomic ions are independently selected, an isobarically pure beam of 70Se ions was postaccelerated to an energy of 206 MeV using REX-ISOLDE. Coulomb-excitation yields for states in the beam and target nuclei were deduced by recording deexcitation γ rays in the highly segmented MINIBALL γ-ray spectrometer in coincidence with scattered particles in a silicon detector. At these energies, the Coulomb-excitation yield for the first 2+ state is expected to be strongly sensitive to the sign of the spectroscopic quadrupole moment through the nuclear reorientation effect. Experimental evidence is presented here for a prolate shape for the first 2+ state in 70Se, reopening the question over whether there are, as reported earlier, deformed oblate shapes near to the ground state in the light selenium isotopes.
International Nuclear Information System (INIS)
Bini, Donato; Geralico, Andrea; Luongo, Orlando; Quevedo, Hernando
2009-01-01
An exact solution of Einstein's field equations in empty space first found in 1985 by Quevedo and Mashhoon is analyzed in detail. This solution generalizes Kerr spacetime to include the case of matter with an arbitrary mass quadrupole moment and is specified by three parameters, the mass M, the angular momentum per unit mass a and the quadrupole parameter q. It reduces to the Kerr spacetime in the limiting case q = 0 and to the Erez-Rosen spacetime when the specific angular momentum a vanishes. The geometrical properties of such a solution are investigated. Causality violations, directional singularities and repulsive effects occur in the region close to the source. Geodesic motion and accelerated motion are studied on the equatorial plane which, due to the reflection symmetry property of the solution, also turns out to be a geodesic plane.
On a Neutral Particle with a Magnetic Quadrupole Moment in a Uniform Effective Magnetic Field
International Nuclear Information System (INIS)
Fonseca, I. C.; Bakke, K.
2016-01-01
Quantum effects on a Landau-type system associated with a moving atom with a magnetic quadrupole moment subject to confining potentials are analysed. It is shown that the spectrum of energy of the Landau-type system can be modified, where the degeneracy of the energy levels can be broken. In three particular cases, it is shown that the analogue of the cyclotron frequency is modified, and the possible values of this angular frequency of the system are determined by the quantum numbers associated with the radial modes and the angular momentum and by the parameters associated with confining potentials in order that bound states solutions can be achieved.
Energy Technology Data Exchange (ETDEWEB)
Hasselgren, L; Fahlander, C; Edvardson, L O; Thun, J E; Falk, F; Ghumman, B S
1975-04-01
The orientation precession technique, REPREC, for measurements of quadrupole moments is described. The application of REPREC to the measurement of the static electric quadrupole moments of the first excited 2/sup +/-states in /sup 108/ /sup 110/Pd is presented. The possibility to measure the matrix product P/sub 4/ = M/sub 02/M/sub 22/,M/sub 02/M/sub 22/ is also discussed. Such measurements are presented for /sup 108/ /sup 110/Pd. The results of these measurements are P/sub 4/O for both /sup 108/Pd and /sup 110/Pd. For /sup 108/Pd the quadrupole moment of the first excited 2/sup +/-state was found to be -.66 +- .18 eb and for /sup 110/Pd -.72 +- .14 eb. Intrinsic nuclear properties for /sup 106 -110/Pd are derived using the sum rules suggested by Kumar.
Energy Technology Data Exchange (ETDEWEB)
Hasselgren, L; Fahlander, C; Falk, F; Edvardson, L O; Thun, J E; Ghuman, B S [Uppsala Univ. (Sweden). Fysiska Institutionen; Skaali, B [Oslo Univ. (Norway). Fysisk Institutt
1976-06-28
The reorientation precession technique, REPREC, for measurements of quadrupole moments is described. The application of REPREC to the measurement of the static electric quadrupole moments of the first excited 2/sup +/ states in /sup 108/ /sup 110/Pd is presented. The possibility to measure the sign of the matrix product P/sub 4/ = M/sub 02/Msub(22')Msub(02')M/sub 22/ is also discussed. Such measurements are presented for /sup 108/ /sup 110/Pd. The results of these measurements are P/sub 4/ < 0 for both /sup 108/Pd and /sup 110/Pd. For /sup 108/Pd the quadrupole moment of the first excited 2/sup +/ state was found to be -0.66+-0.18e.b and for /sup 110/Pd, -0.72+-0.14e.b. Intrinsic nuclear properties for /sup 106 -110/Pd are derived using the sum rules suggested by Kumar.
International Nuclear Information System (INIS)
Netz, G.
1974-01-01
The quadrupole moments of two single particle proton states were measured in the strongly deformed nuclei region. Both measurements are independent of model because the field gradient is known in a rhenium lattice as well as at the nucleus site of a rhenium atom and also at the nucleus site of an incorporated tantalum atom. The quadrupole moments could thus be directly extracted from the quadrupole interaction frequency, the product of quadrupole moment and field gradient. For the 482 keV state (I = 5/2 + ) in 181 73 Ta 108 one obtains a quadrupole moment of: Q (5/2) = 2.5 +- 0.2 barn. For the 496 keV state (I = 9/2 - ) in 183 75 Re 108 , a quadrupole moment of: Q (0/2) = 3.6 +- 0.4 barn is found. This value agrees well with other experimental data within the framework of the collective model. (orig./LH) [de
Quadrupole moments of Cd and Zn nuclei: When solid-state, molecular, atomic, and nuclear theory meet
DEFF Research Database (Denmark)
Haas, Heinz; Sauer, Stephan P. A.; Hemmingsen, Lars Bo Stegeager
2017-01-01
The nuclear quadrupole moment (Q) of the 5/2+ isomeric state of 111Cd, of particular importance to the interpretation of Perturbed Angular Correlation experiments in condensed matter, was determined by combining existing PAC data with high-level ab initio (CCSD(T)) calculations for Cd-dimethyl an......The nuclear quadrupole moment (Q) of the 5/2+ isomeric state of 111Cd, of particular importance to the interpretation of Perturbed Angular Correlation experiments in condensed matter, was determined by combining existing PAC data with high-level ab initio (CCSD(T)) calculations for Cd...
International Nuclear Information System (INIS)
Sakai, Hisashi; Takiyama, Ken; Kimura, Masahiko; Yamasaki, Motokuni; Fujita, Toshiaki; Oda, Toshiatsu; Kawasaki, Ken.
1993-01-01
The electric quadrupole moment transition and the Stark effect are investigated in a He hollow cathode discharge with laser-induced fluorescence method. It is shown that the forbidden transition from 2 1 S to 3 1 D in the negative glow is dominantly due to the quadrupole moment transition. This absorption coefficient is obtained from the laser-induced fluorescence intensity measurement in which the collisional transfers are taken into account. The result agrees with the theoretical coefficient. In the cathode dark space the fluorescence due to the Stark effect is also observed. Spatial distribution of the fluorescence is discussed, compared with the electric field distribution in the dark space. (author)
International Nuclear Information System (INIS)
Gou, Dezhi; Kuang, Xiaoyu; Gao, Yufeng; Huo, Dongming
2015-01-01
In this paper, we systematically investigate the electronic structure for the 2 Σ + ground state of the polar alkali-metal-alkaline-earth-metal molecules BaAlk (Alk = Li, Na, K, Rb, and Cs). Potential energy curves and permanent dipole moments (PDMs) are determined using power quantum chemistry complete active space self-consistent field and multi-reference configuration interaction methods. Basic spectroscopic constants are derived from ro-vibrational bound state calculation. From the calculations, it is shown that BaK, BaRb, and BaCs molecules have moderate values of PDM at the equilibrium bond distance (BaK:1.62 D, BaRb:3.32 D, and BaCs:4.02 D). Besides, the equilibrium bond length (4.93 Å and 5.19 Å) and dissociation energy (0.1825 eV and 0.1817 eV) for the BaRb and BaCs are also obtained
The quadrupole moment of the first excited state of 18O
International Nuclear Information System (INIS)
Fewel, M.P.; Baxter, A.M.; Kean, D.C.; Spear, R.H.
1976-11-01
Using the re-orientation effect in Coulomb excitation, the quadrupole moment, Qsub(2 + ), of the first excited state of 18 O is found to be -0.100 +- 0.030 eb. The analysis assumes, on the basis of previous measurements, that B(E2; 0 + → 2 + ) = 0.0044 +- 0.0004 e 2 b 2 . A correction (+0.032 eb) for the effect of the giant dipole resonance, based on the hydrodynamic model, has been applied. Evidence is presented that some other determinations of Qsub(2 + ) were performed at too high a bombarding energy. The present value of Qsub(2 + ) is smaller in magnitude than that reported by Kleinfeld et al. (1975), but remains larger than the value of -0.034 eb predicted by a recent shell-model calculation. (Author)
The charge form factor and quadrupole moment of lithium-6 and -7
International Nuclear Information System (INIS)
Srinivasa Rao, K.; Susila, S.; Sridhar, R.
1980-01-01
The cluster model wave functions for lithium-6 and -7 are constructed from a two oscillator shell model wave function assuming the nucleons belonging to the clusters to be in the 1s- and 1p-shells, respectively. After first finding the range of values of the parameters in the wave function for which acceptable values of the r.m.s. radius are obtained, the range is considerably refined by a study of the form factors of these cluster nuclei. A deformation parameter is introduced in the wave functions, to get a non-spherical charge density. This parameter is uniquely fixed by the quadrupole moment for the nucleus. The model wave functions are considered to be the desirable ones for the study of cluster-knock-out reactions. (author)
Electric quadrupole moments of the 2$_{1}^{+}$ states in $^{100,102,104}$Cd
Ekström, A; DiJulio, D D; Fahlander, C; Hjorth-Jensen, M; Blazhev, A; Bruyneel, B; Butler, P A; Davinson, T; Eberth, J; Fransen, C; Geibel, K; Hess, H; Ivanov, O; Iwanicki, J; Kester, O; Kownacki, J; Köster, U; Marsh, B A; Reiter, P; Scheck, M; Siebeck, B; Siem, S; Stefanescu, I; Toft, H K; Tveten, G M; van de Walle, J; Voulot, D; Warr, N; Weisshaar, D; Wenander, F; Wrzosek, K; Zielińska, M
2009-01-01
Using the REX-ISOLDE facility at CERN the Coulomb excitation cross sections for the 0gs+→21+ transition in the β-unstable isotopes 100,102,104Cd have been measured for the first time. Two different targets were used, which allows for the first extraction of the static electric quadrupole moments Q(21+) in 102,104Cd. In addition to the B(E2) values in 102,104Cd, a first experimental limit for the B(E2) value in 100Cd is presented. The data was analyzed using the maximum likelihood method. The provided probability distributions impose a test for theoretical predictions of the static and dynamic moments. The data are interpreted within the shell-model using realistic matrix elements obtained from a G-matrix renormalized CD-Bonn interaction. In view of recent results for the light Sn isotopes the data are discussed in the context of a renormalization of the neutron effective charge. This study is the first to use the reorientation effect for post-accelerated short-lived radioactive isotopes to simultaneously d...
Quadrupole moment of the 7/21- isomer state in 43S. Shell model study of sulfur isotopes around N=28
International Nuclear Information System (INIS)
Chevrier, Raphael
2013-01-01
The goal of this work consists in providing new insights in the shape coexistence expected in neutron-rich nuclei around the N=28 shell closure. In 43 S, recent experimental data as well as their interpretation in the shell model framework were used to predict the coexistence between a J π =3/2 1 - prolate deformed ground state and a 7/2 1 - rather spherical isomer state. We report on the quadrupole moment measurement Q s of the 7/2 1 - isomer state [E*=320.5(5) keV, T 1/2 =415(3) ns] in 43 S. The TDPAD method was applied on 43 S nuclei produced by the fragmentation of a 48 Ca primary beam at 345 A.MeV, and selected in-flight through the BigRIPS spectrometer at RIKEN (Japan). The measured value, |Q s |=23(3) efm 2 , is in remarkable agreement with that calculated in the shell model framework, although it is significantly larger than that expected for a single-particle state. In order to understand the nature of the correlations responsible for the departure of the isomer state from a pure spherical shape, we report on the results of a shell model study using the modern SDPF-U interaction of the neighbors sulfur isotopes 42,44,46 S. Those calculations allowed to identify a slight triaxial degree of freedom in the structure of these nuclei, although the latter happens to be highly hindered at N=28 in 44 S. Spectroscopic factor calculations show that this slight triaxial degree of freedom also impacts the low-lying structure in 43 S. It allows to better understand the deviation of the spectroscopic quadrupole moment value of the isomer state from the limit case of a pure spherical state. (author) [fr
Hyperfine interaction of {sup 25}Al in {alpha}-Al{sub 2}O{sub 3} and its quadrupole moment
Energy Technology Data Exchange (ETDEWEB)
Matsuta, K., E-mail: matsuta@vg.phys.sci.osaka-u.ac.jp; Mihara, M. [Osaka University, Department of Physics (Japan); Nagatomo, T. [RIKEN (Japan); Matsumiya, R. [Osaka University, Department of Physics (Japan); Momota, S. [Kochi University of Technology (Japan); Ohtsubo, T. [Niigata University, Department of Physics (Japan); Izumikawa, T. [Niigata University, Radioisotope Center (Japan); Hirano, H.; Takahashi, S. [Niigata University, Department of Physics (Japan); Nishimura, D.; Komurasaki, J. [Osaka University, Department of Physics (Japan); Kitagawa, A.; Kanazawa, M.; Torikoshi, M.; Sato, S. [National Institute of Radiological Sciences (Japan); Fukuda, M. [Osaka University, Department of Physics (Japan); Minamisono, T. [Fukui University of Technology (Japan); Sumikama, T. [Tokyo University of Science (Japan); Tanaka, K.; Takechi, M. [RIKEN (Japan)
2007-11-15
The electric quadrupole (Q) moment of short-lived nucleus {sup 25}Al (I{sup {pi}} = 5/2{sup +}, T{sub 1/2} = 7.18 s) has been measured for the first time, by means of the {beta}-NQR technique. The spin polarization of {sup 25}Al was produced in heavy ion collisions and was kept in a {alpha}-Al{sub 2}O{sub 3} single crystal for as long as 2 s and the quadrupole coupling frequency was obtained as vertical bar eqQ / h({sup 25}Al in Al{sub 2}O{sub 3}) vertical bar = (4.05 {+-}0.30) MHz. From the result, the Q moment was determined as |Q({sup 25}Al)| = (240 {+-}20) mb. The present Q moment is larger by 30% than the shell model value of 184 mb, calculated by OXBASH code, which may show additional deformation of the nucleus.
The g-factor and the electric quadrupole moment of the 7/2+ isomer in 125Xe
International Nuclear Information System (INIS)
Alber, D.; Bertschat, H.H.; Grawe, H.; Haas, H.; Mahnke, H.E.; Menningen, M.; Semmler, W.; Sielemann, R.; Zeitz, W.D.; Freie Univ. Berlin
1983-01-01
The time differential perturbed angular distribution method (PAD) was used to measure the g-factor and the electric quadrupole interaction in a Cd single crystal for the tsub(1/2)=140 ns, Isup(π)=7/2 + isomer in 125 Xe. The g-factor is g=+0.264(10) and the quadrupole coupling constant e 2 Qq/h=122.1(6) MHz at 552 K. The lifetime of the Isup(π)=11/2 + state was measured to be tau=11.3(1.1) ps by the recoil distance method (RDM). From an analysis of the spectroscopic data using the triaxial-rotor-pulse-particle (TRPP) model the quadrupole moment of the 7/2 + isomer is deduced to be Q=1.40(15) b yielding an electric field gradient (efg) eq=3.6(4)x10 17 V/cm 2 for Xe Cd. (orig.)
The g-factor and the electric quadrupole moment of the 7/2+ isomer in 125Xe
International Nuclear Information System (INIS)
Alber, D.; Bertschat, H.H.; Grawe, H.; Haas, H.; Mahnke, H.E.; Menningen, M.; Semmler, W.; Sielemann, R.; Zeitz, W.D.
1983-01-01
The time differential perturbed angular distribution method (PAD) was used to measure the g-factor and the electric quadrupole interaction in a Cd single crystal for the tsub(1/2) = 140 ns, Isup(π) = 7/2 + isomer in 125 Xe. The g-factor is g = +0.264(10) and the quadrupole coupling constant e 2 Qq/h = 122.1(6) MHz at 552 K. The lifetime of the Isup(π) = 11/2 + state was measured to be tau = 11.3(1.1) ps by the recoil distance method (RDM). From an analysis of the spectroscopic data using the triaxial-rotor-plus-particle (TRPP) model the quadrupole moment of the 7/2 + isomer is deduced to be Q = 1.40(15) b yielding an electric field gradient (efg) eq = 3.6(4)x10 17 V/cm 2 for Xe Cd. (orig.)
Dirkes, Alain
2018-04-01
We recently suggested a nonlocal modification of Einstein’s field equations in which Newton’s constant G was promoted to a covariant differential operator G_Λ(\\Box_g) . The latter contains two independent contributions which operate respectively in the infrared (IR) and ultraviolet (UV) energy regimes. In the light of the recent direct gravitational radiation measurements we aim to determine the UV-modified 1.5 post-Newtonian radiative quadrupole moment of a generic n-body system. We eventually use these preliminary results in the context of a binary system and observe that in the limit vanishing UV parameters we precisely recover the corresponding general relativistic results. Moreover we notice that the leading order deviation of the UV-modified radiative quadrupole moment numerically coincides with findings obtained in the framework of calculations performed previously in the context of the perihelion precession of Mercury.
Sudden change of quadrupole moment between the first 5/2- states of 197Hg and 199Hg
International Nuclear Information System (INIS)
Herzog, P.; Krien, K.; Freitag, M.; Reuschenbach, M.; Walitzki, H.
1980-01-01
Low-temperature time differential perturbed angular correlation experiments with the 164 KeV-134 keV cascade of sup(197m)Hg in a zinc matrix give evidence that the hitherto accepted value of the quadrupole moment of the first 5/2 - state of 197 Hg is erroneous. A new value is derived from a time differential perturbed angular correlation experiment with the 374 keV-158 keV cascade of sup(199m)Hg implanted into a Be single crystal and comparison with an analogous experiment for sup(197m)Hg. Taking Q(5/2 - , 199 Hg) = +0.95(7) b we derive Q(5/2 - , 197 Hg) = 0.081(6) b. This change of quadrupole moment is discussed in the framework of the shell model. (orig.)
LEMS: application of the method to study the static quadrupole moment of the K=35/2 isomer in 179W
International Nuclear Information System (INIS)
Neyens, G.; Vyvey, K.; Byrne, A.P.; Dracoulis, G.D.; Blaha, P.
1997-01-01
The method of the level mixing spectroscopy (LEMS) was applied for the first time for the study of the static quadrupole moments of high-K isomers in the A∼180 mass region. Results from a preliminary experiment for the static quadrupole moment of the 35/2 - (750 ns) isomer in 179 W give a limit for its upper value Q 2 <0.343. (orig.). With 1 fig
Smolic, E; Hagn, E; Zech, E; Seewald, G
2002-01-01
The aim of the experiments is the measurement of $\\,$i) nuclear magnetic moments and electric quadrupole moments of neutron-deficient isotopes in the region Os-Ir-Pt-Au with the methods of quadrupole-interaction-resolved NMR on oriented nuclei " QI-NMR-ON " and modulated adiabatic passage on oriented nuclei " MAPON " and $\\,$ii) the magnetic hyperfine field, electric field gradient (EFG), and spin-lattice relaxation of 5d elements in ferromagnetic Fe, Ni, fcc-Co and hcp-Co.\\\\ The measurements on Au isotopes have been finished successfully. The quadrupole moments of $^{186}$Au, $^{193m}$Au, $^{195}$Au, $^{195m}$Au, $^{197m}$Au, $^{198}$Au and $^{199}$Au were determined with high precision.\\\\ For neutron-deficient Ir isotopes QI-NMR-ON measurements were performed after implantation of Hg precursors. The EFG of Ir in hcp-Co has been calibrated. Thus precise values for the spectroscopic quadrupole mo...
Static quadrupole moments of first 2+ states in the 2s1d shell: a review of experiment and theory
International Nuclear Information System (INIS)
Spear, R.H.
1981-01-01
Available experimental information on the static electric quadrupole moments Q 2 + of the 2 + first excited states of even-mass nuclei in the 2s-1d shell is tabulated and critically reviewed, and adopted values are presented. The results reveal a well defined pattern for the variation of Q 2 + through the shell. Predictions of Q 2 + made from various nuclear models are tabulated and compared with experiment. For each nucleus the quantity and quality of the existing data for Q 2 + , together with the current theoretical significance of the result, are used as criteria to determine whether new experimental work is desirable
Deterioration of the Skew Quadrupole Moment in Tevatron Dipoles Over Time
Syphers, Michael J
2005-01-01
During the 20 years since it was first commissioned, the Fermilab Tevatron has developed strong coupling between the two transverse degrees of freedom. A circuit of skew quadrupole magnets is used to correct for coupling and, though capable, its required strength has increased since 1983 by more than an order of magnitude. In more recent years changes to the Tevatron for colliding beams operation have altered the skew quadrupole corrector distribution and strong local coupling become evident, often encumbering routine operation during the present physics run. Detailed magnet measurements were performed on each individual magnet during construction, and in early 2003 it was realized that measurements could be performed on the magnets in situ which could determine coil movements within the iron yoke since the early 1980's. It was discovered that the superconducting coils had become vertically displaced relative to their yokes since their construction. The ensuing systematic skew quadrupole field introduced by t...
An effect of nuclear electric quadrupole moments in thermonuclear fusion plasmas
De, B. R.; Srnka, L. J.
1978-01-01
Consideration of the nuclear electric quadrupole terms in the expression for the fusion Coulomb barrier suggests that this electrostatic barrier may be substantially modified from that calculated under the usual plasma assumption that the nuclei are electric monopoles. This effect is a result of the nonspherical potential shape and the spatial quantization of the nuclear spins of the fully stripped ions in the presence of a magnetic field. For monopole-quadrupole fuel cycles like p-B-11, the fusion cross-section may be substantially increased at low energies if the protons are injected at a small angle relative to the confining magnetic field.
International Nuclear Information System (INIS)
Laat, C.T.A.M. de; Taal, A.; Duinker, W.; Konijn, J.; Petitjean, C.; Reist, H.W.; Mueller, W.; Commission of the European Communities, Geel
1987-01-01
The X-ray spectrum of muonic and pionic 237 Np has been investigated with muons and pions stopped in a NpO 2 target. The nuclear spectroscopic quadrupole moment was determined to be Q=3.886±0.006 b from the splittings of the muonic 5g→4f hyperfine complexes. The B(E2)↓-values for the first and second excited states were evaluated as 3.17±0.08 and 2.77±0.10 e 2 b 2 , respectively. A comparison between the muonic and pionic 5g→4f hyperfine complexes yields the strong interaction parameter for the pionic 4f state. For the first time a change of sign as function of Z for the strong interaction quadrupole shift ε 2 (4f) has been observed. The standard optical model predictions agree reasonably well with the measured strong interaction monopole shift, ε 0 (4f), and width, Γ 0 (4f), while they disagree with the experimental value for ε 2 . A stronger s-wave repulsion in the optical potential could explain this effect. (orig.)
DEFF Research Database (Denmark)
Hansen, Flemming Yssing; Alldredge, G. P.; Bruch, L. W.
1985-01-01
and gives a repulsive rather than an attractive electrostatic interaction at typical intermolecular distances. In the local multipole model, the atom-site dipoles give the largest contribution to both the molecular quadrupole moment and the intermolecular interaction. The Journal of Chemical Physics...
Friedrich, Manuel; Stefanelli, Ulisse
2018-06-01
Graphene is locally two-dimensional but not flat. Nanoscale ripples appear in suspended samples and rolling up often occurs when boundaries are not fixed. We address this variety of graphene geometries by classifying all ground-state deformations of the hexagonal lattice with respect to configurational energies including two- and three-body terms. As a consequence, we prove that all ground-state deformations are either periodic in one direction, as in the case of ripples, or rolled up, as in the case of nanotubes.
International Nuclear Information System (INIS)
Negele, J.W.
1975-01-01
The nuclear ground state is surveyed theoretically, and specific suggestions are given on how to critically test the theory experimentally. Detailed results on 208 Pb are discussed, isolating several features of the charge density distributions. Analyses of 208 Pb electron scattering and muonic data are also considered. 14 figures
Singlet Ground State Magnetism:
DEFF Research Database (Denmark)
Loidl, A.; Knorr, K.; Kjems, Jørgen
1979-01-01
The magneticGamma 1 –Gamma 4 exciton of the singlet ground state system TbP has been studied by inelastic neutron scattering above the antiferromagnetic ordering temperature. Considerable dispersion and a pronounced splitting was found in the [100] and [110] directions. Both the band width...
International Nuclear Information System (INIS)
Laird, R.W.; Riley, M.A.; Brown, T.B.; Pfohl, J.; Sheline, R.K.; Kondev, F.G.; Archer, D.E.; Clark, R.M.; Fallon, P.; Devlin, M.; LaFosse, D.R.; Sarantites, D.G.; Hartley, D.J.; Hibbert, I.M.; O'Brien, N.J.; Wadsworth, R.; Joss, D.T.; Nolan, P.J.; Paul, E.S.; Shepherd, S.L.
2002-01-01
The latest generation γ-ray detection system, GAMMASPHERE, coupled with the Microball charged-particle detector, has made possible a new class of nuclear lifetime measurement. For the first time differential lifetime measurements free from common systematic errors for over 15 different nuclei (>30 rotational bands in various isotopes of Ce, Pr, Nd, Pm, and Sm) have been extracted at high spin within a single experiment. This comprehensive study establishes the effective single-particle transition quadrupole moments in the A∼135 light rare-earth region. Detailed comparisons are made with theoretical calculations using the self-consistent cranked mean-field theory which convincingly demonstrates the validity of the additivity of single-particle quadrupole moments in this mass region
International Nuclear Information System (INIS)
Pedersen, J.; Goerlach, U.; Habs, D.; Just, M.; Metag, V.; Mosler, E.; Schukraft, J.; Singer, P.; Specht, H.J.; Ulfert, G.
1978-01-01
A modified version of the charge plunger method has been developed which, by utilizing electrostatic fields, renders possible the separation of low- and high-charge recoil ions over short flight distances. With this technique the quadrupole moment of the 200 ns fission isomer in 238 U has been determined to be (29 +- 3) b. The corresponding deformation of c/a = (1.8 +- 0.1) provides another quantitative proof for shape isomerism in the actinide region. (orig.) [de
International Nuclear Information System (INIS)
Olaniyi, B.; Shor, A.; Cheng, S.C.; Dugan, G.; Wu, C.S.
1981-05-01
The effective quadrupole moments Q sub(eff) of the nuclei of 165 Ho, 175 Lu, 176 Lu, 179 Hf and 181 Ta were accurately measured by detecting the pionic atom 5g-4f x-rays of the elements. The spectroscopic quadrupole moments, Q sub(spec), were obtained by correcting Q sub(eff) for nuclear finite size effect, distortion of the pion wave function by the pion-nucleus strong interaction, and contribution to the energy level splittings by the strong interaction. The intrinsic quadrupole moments, Q 0 , were obtained by projecting Q sub(spec) into the frame of reference fixed on the nucleus. The shift, epsilon 0 , and broadening, GAMMA 0 , of the 4f energy level due to the strong interactions between the pion and the nucleons for all the elements were also measured. Theoretical values of epsilon 0 and GAMMA 0 were calculated and compared to the experimental values. The measured values of Q 0 were compared with the existing results in muonic and pionic atoms. The measured values of epsilon 0 and GAMMA 0 were also compared with existing values. (auth)
International Nuclear Information System (INIS)
Wei, Jie; Li, Xiao-Ping; Sessler, A.M.
1993-01-01
In order to employ Molecular Dynamics method, commonly used in condensed matter physics, we have derived the equations of motion for a beam of charged particles in the rotating rest frame of the reference particle. We include in the formalism that the particles are confined by the guiding and focusing magnetic fields, and that they are confined in a conducting vacuum pipe while interacting with each other via a Coulomb force. Numerical simulations has been performed to obtain the equilibrium structure. The effects of the shearing force, centrifugal force, and azimuthal variation of the focusing strength are investigated. It is found that a constant gradient storage ring can not give a crystalline beam, but that an alternating-gradient (AG) structure can. In such a machine the ground state is, except for one-dimensional (1-D) crystals, time-dependent. The ground state is a zero entropy state, despite the time-dependent, periodic variation of the focusing force. The nature of the ground state, similar to that found by Rahman and Schiffer, depends upon the density and the relative focusing strengths in the transverse directions. At low density, the crystal is 1-D. As the density increases, it transforms into various kinds of 2-D and 3-D crystals. If the energy of the beam is higher than the transition energy of the machine, the crystalline structure can not be formed for lack of radial focusing
International Nuclear Information System (INIS)
Wei, Jie; Li, Xiao-Ping
1993-01-01
In order to employ molecular dynamics (MD) methods, commonly used in condensed matter physics, we have derived the equations of motion for a beam of charged particles in the rotating rest frame of the reference particle. We include in the formalism that the particles are confined by the guiding and focusing magnetic fields, and that they are confined in a conducting vacuum pipe while interacting with each other via a Coulomb force. Numerical simulations using MD methods has been performed to obtain the equilibrium crystalline beam structure. The effect of the shearing force, centrifugal force, and azimuthal variation of the focusing strength are investigated. It is found that a constant gradient storage ring can not give a crystalline beam, but that an alternating-gradient (AG) structure can. In such a machine the ground state is, except for one-dimensional (1-D) crystals, time dependent. The ground state is a zero entropy state, despite the time-dependent, periodic variation of the focusing force. The nature of the ground state, similar to that found by Schiffer et al. depends upon the density and the relative focusing strengths in the transverse directions. At low density, the crystal is 1-D. As the density increases, it transforms into various kinds of 2-D and 3-D crystals. If the energy of the beam is higher than the transition energy of the machine, the crystalline structure can not be formed for lack of radial focusing
International Nuclear Information System (INIS)
Wei, J.; Li, X.P.
1993-01-01
In order to employ the Molecular Dynamics method, commonly used in condensed matter physics, the authors have derived the equations of motion for a beam of charged particles in the rotating rest frame of the reference particle. They include in the formalism that the particles are confined by the guiding and focusing magnetic fields, and that they are confined in a conducting vacuum pipe while interacting with each other via a Coulomb force. Numerical simulations has been performed to obtain the equilibrium structure. The effects of the shearing force, centrifugal force, and azimuthal variation of the focusing strength are investigated. It is found that a constant gradient storage ring can not give a crystalline beam, but that an alternating-gradient (AG) structure can. In such a machine the ground state is, except for one-dimensional (1-D) crystals, time-dependent. The ground state is a zero entropy state, despite the time-dependent, periodic variation of the focusing force. The nature of the ground state, similar to that found by Rahman and Schiffer, depends upon the density and the relative focusing strengths in the transverse directions. At low density, the crystal is 1-D. As the density increases, it transforms into various kinds of 2-D and 3-D crystals. If the energy of the beam is higher than the transition energy of the machine, the crystalline structure can not be formed for lack of radial focusing
Lattice distortion and spontaneous Γ5g ferro-quadrupole moment in phase IV of CexLa1-xB6
International Nuclear Information System (INIS)
Nemoto, Yuichi; Akatsu, Mitsuhiro; Goto, Terutaka; Suzuki, Osamu; Nakamura, Shintaro; Kunii, Satoru
2005-01-01
We have performed low-temperature thermal expansion measurements to investigate lattice effect of the phase IV in Ce x La 1-x B 6 , for x=0.75 and 0.70. In phase IV of both compounds, lattice length along the [111] direction shrinks notably, on the other hand length along the [001] direction expands. These results provide evidence that the spontaneous Γ 5g ferro-quadrupole moment yz >= zx >= xy > 0 is relevant in phase IV because the trigonal lattice distortion is described by the symmetry strain yz >= zx >= xy > 0 simultaneously
Kopferman, H; Massey, H S W
1958-01-01
Nuclear Moments focuses on the processes, methodologies, reactions, and transformations of molecules and atoms, including magnetic resonance and nuclear moments. The book first offers information on nuclear moments in free atoms and molecules, including theoretical foundations of hyperfine structure, isotope shift, spectra of diatomic molecules, and vector model of molecules. The manuscript then takes a look at nuclear moments in liquids and crystals. Discussions focus on nuclear paramagnetic and magnetic resonance and nuclear quadrupole resonance. The text discusses nuclear moments and nucl
International Nuclear Information System (INIS)
Forssen, C.; Caurier, E.; Navratil, P.
2009-01-01
Recently, charge radii and ground-state electromagnetic moments of Li and Be isotopes were measured precisely. We have performed large-scale ab initio no-core shell model calculations for these isotopes using high-precision nucleon-nucleon potentials. The isotopic trends of our computed charge radii and quadrupole and magnetic-dipole moments are in good agreement with experimental results with the exception of the 11 Li charge radius. The magnetic moments are in particular well described, whereas the absolute magnitudes of the quadrupole moments are about 10% too small. The small magnitude of the 6 Li quadrupole moment is reproduced, and with the CD-Bonn NN potential, also its correct sign
A comparative icMRCI study of some NO+, NO and NO- electronic ground state properties
International Nuclear Information System (INIS)
Polak, R.; Fiser, J.
2004-01-01
Potential energy, electric field gradient (EFG) at both nuclei, and electric dipole moment functions for the electronic ground states of NO + , NO and NO - were calculated at the internally contracted multireference configuration interaction (icMRCI) level using augmented correlation-consistent basis sets. The changes in the EFG's with internuclear separation R were used to interpret the character of bonding in the triad of NO species. The vibrational dependences of the electric properties were estimated and the EFG's were employed to determine the 14 N nuclear quadrupole coupling constants. The effects of the choice of the basis set and reference configuration space were investigated. While the results obtained for NO + and NO served primarily to assess the quality of calculations by comparison with available experimental and theoretical data, new information was obtained on NO - , including electric property functions and some notions about the existence of metastable states
Energy Technology Data Exchange (ETDEWEB)
Yoruk, Abdulkadir, E-mail: yorukabdulkadir@hotmail.com [Süleyman Demirel University, Nursery Medical School (Turkey); Turkan, Nureddin, E-mail: nureddin.turkan@medeniyet.edu.tr [Istanbul Medeniyet University, Faculty of Science (Turkey)
2016-09-15
We have carried out the calculation of the quadrupole moments Q(2{sub 1}{sup +}) and electromagnetic transition rates B(E2) of some levels within the framework of the interacting boson model for even-mass Ge nuclei. The presented predictions of the quadrupole moments and B(E2) ratios for Ge nuclei are compared with the results of some previous experimental and theoretical ones along with those of the neighboring Kr and Se isotopes and then it was seen that they agree well with the previous experimental and theoretical ones.
Clément, E; Zielińska, M; Görgen, A; Korten, W; Péru, S; Libert, J; Goutte, H; Hilaire, S; Bastin, B; Bauer, C; Blazhev, A; Bree, N; Bruyneel, B; Butler, P A; Butterworth, J; Delahaye, P; Dijon, A; Doherty, D T; Ekström, A; Fitzpatrick, C; Fransen, C; Georgiev, G; Gernhäuser, R; Hess, H; Iwanicki, J; Jenkins, D G; Larsen, A C; Ljungvall, J; Lutter, R; Marley, P; Moschner, K; Napiorkowski, P J; Pakarinen, J; Petts, A; Reiter, P; Renstrøm, T; Seidlitz, M; Siebeck, B; Siem, S; Sotty, C; Srebrny, J; Stefanescu, I; Tveten, G M; Van de Walle, J; Vermeulen, M; Voulot, D; Warr, N; Wenander, F; Wiens, A; De Witte, H; Wrzosek-Lipska, K
2016-01-15
Neutron-rich {96,98}Sr isotopes have been investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross sections. These results allow, for the first time, the drawing of definite conclusions about the shape coexistence of highly deformed prolate and spherical configurations. In particular, a very small mixing between the coexisting states is observed, contrary to other mass regions where strong mixing is present. Experimental results have been compared to beyond-mean-field calculations using the Gogny D1S interaction in a five-dimensional collective Hamiltonian formalism, which reproduce the shape change at N=60.
Spins, moments and charge radii beyond $^{48}$Ca
Neyens, G; Rajabali, M M; Hammen, M; Blaum, K; Froemmgen, N E; Garcia ruiz, R F; Kreim, K D; Budincevic, I
Laser spectroscopy of $^{49-54}$Ca is proposed as a continuation of the experimental theme initiated with IS484 “Ground-state properties of K-isotopes from laser and $\\beta$-NMR spectroscopy” and expanded in INTC-I-117 “Moments, Spins and Charge Radii Beyond $^{48}$Ca.” It is anticipated that the charge radii of these isotopes can show strong evidence for the existence of a sub-shell closure at N=32 and could provide a first tentative investigation into the existence of a shell effect at N=34. Furthermore the proposed experiments will simultaneously provide model-independent measurements of the spins, magnetic moments and quadrupole moments of $^{51,53}$Ca permitting existing and future excitation spectra to be pinned to firm unambiguous ground states.
Global study of quadrupole correlation effects
International Nuclear Information System (INIS)
Bender, M.; Bertsch, G.F.; Heenen, P.-H.
2006-01-01
We discuss the systematics of ground-state quadrupole correlations of binding energies and mean-square charge radii for all even-even nuclei, from 16 O up to the superheavies, for which data are available. To that aim we calculate their correlated J=0 ground state by means of the angular-momentum and particle-number projected generator coordinate method, using the axial mass quadrupole moment as the generator coordinate and self-consistent mean-field states restricted only by axial, parity, and time-reversal symmetries. The calculation is performed within the framework of a nonrelativistic self-consistent mean-field model by use of the same Skyrme interaction SLy4 and to a density-dependent pairing force to generate the mean-field configurations and to mix them. These are the main conclusions of our study: (i) The quadrupole correlation energy varies between a few 100 keV and about 5.5 MeV. It is affected by shell closures, but varies only slightly with mass and asymmetry. (ii) Projection on angular momentum J=0 provides the major part of the energy gain of up to about 4 MeV; all nuclei in the study, including doubly magic ones, gain energy by deformation. (iii) The mixing of projected states with different intrinsic axial deformations adds a few 100 keV up to 1.5 MeV to the correlation energy. (iv) Typically nuclei below mass A≤60 have a larger correlation energy than static deformation energy whereas the heavier deformed nuclei have larger static deformation energy than correlation energy. (v) Inclusion of the quadrupole correlation energy improves the description of mass systematics, particularly around shell closures, and of differential quantities, namely two-nucleon separation energies and two-nucleon gaps. The correlation energy provides an explanation of 'mutually enhanced magicity'. (vi) The correlation energy tends to decrease the shell effect on binding energies around magic numbers, but the magnitude of the suppression is not large enough to explain
Directory of Open Access Journals (Sweden)
Irzaman
2004-12-01
Full Text Available ZT (PbZr1-xTixO3 is a perovskite crystal that can be used for IR sensor. Small amount of dopant can drastically change the specific characteristic of ferroelectric ceramic such as spontaneous polarization, dielectric constant, electromechanical and also electro-optic properties. The addition of In3+ ion (called as hard doping has been applied in this research. Thin film of PIZT (PbInxZryTi1-x-yO3-x/2 has been deposited on Si(100 substrate with Chemical Solution Deposition (CSD method. The concentration of solution is 0,5 M and the angular speed applied of spin coating is 3000 rpm. The PIZT sample has been analyzed with x-ray diffraction method. Rietveld analyses using GSAS-EXPGUI software resulted lattice parameter of crystal and phase compositions of PIZT samples. The values of all sample PIZT spontaneous polarization (Ps have been calculated lower than PZT. The optimally Ps was reached at 0,5% to 1% In2O3 doping. Quadrupole moment of electric potential (ΦQ(r at point P (0,0,2a reached optimum at 6% In2O3 doping and they also showed that PIZT thin film have ΦQ(r higher value than their bulk form for In2O3 doping >1%.
Measurement of the ground-state hyperfine splitting of antihydrogen
Juhász, B; Federmann, S
2011-01-01
The ASACUSA collaboration at the Antiproton Decelerator of CERN is planning to measure the ground-state hyperfine splitting of antihydrogen using an atomic beam line, consisting of a cusp trap as a source of partially polarized antihydrogen atoms, a radiofrequency spin-flip cavity, a superconducting sextupole magnet as spin analyser, and an antihydrogen detector. This will be a measurement of the antiproton magnetic moment, and also a test of the CPT invariance. Monte Carlo simulations predict that the antihydrogen ground-state hyperfine splitting can be determined with a relative precision of ~10−7. The first preliminary measurements of the hyperfine transitions will start in 2011.
International Nuclear Information System (INIS)
Tanida, Hiroshi; Takagi, Shigeru; Suzuki, Hiroyuki S.; Satoh, Isamu; Komatsubara, Takemi
2006-01-01
Microscopic properties have been investigated on a cubic nonmagnetic non-Kramers Γ 3 doublet ground-state (GS) system PrAg 2 In by complementarily utilizing 115 In (I=9/2) and 109 Ag (I=1/2) NMR with particular emphasis on the low-frequency (low-ω) dipole and multipole (octupole and/or quadrupole) fluctuations of f-electrons as probed by the nuclear spin relaxation rates 1/ 115 T 1 and 1/ 109 T 1 . We show that 1/ 115 T 1 and 1/ 109 T 1 are anomalously enhanced respectively below≅50 K and ≅100K over those expected for the low-ω dipole fluctuations of the excited magnetic Γ 4 and Γ 5 states in a simple crystalline-electric-field model for a Γ 3 GS system. By comparing 1/( 115 T 1 T) and 1/( 109 T 1 T) and also by considering an invariant form of the hyperfine and/or quadrupole couplings of Γ 3 octupole and/or quadrupole moments with Ag/In nuclear dipole and/or quadrupole moments, we show that Γ 3 octupole fluctuations dominate 1/ 109 T 1 and quadrupole ones can possibly contribute to 1/ 115 T 1 at low T. (author)
Nuclear Ground State Properties in Strontium by Fast Beam Laser Spectroscopy
2002-01-01
Hyperfine structures and isotope shifts of strontium isotopes with A=78 to A=100 were measured by collinear fast beam laser spectroscopy. Nuclear spins, moments and changes in mean square charge radii are extracted from the data. The spins and moments of most of the odd isotopes are explained in the framework of the single particle model. The changes in mean square charge radii show a decrease with increasing neutron number below the N=50 shell closure. Above N=50 the charge radii increase regularly up to N=59 before revealing a strong discontinuity, indicating the onset of strong ground state deformation. A comparison of the droplet model shows that for the transitional isotopes below and above N=50, the zero point quadrupole motion describes part of the observed shell effect. Calculations carried out in the Hartree-Fock plus BCS model suggest an additional change in the surface region of the charge distribution at spherical shape. From these calculations it is furthermore proposed, that the isotopes $^7
Ground states of quantum spin systems
International Nuclear Information System (INIS)
Bratteli, Ola; Kishimoto, Akitaka; Robinson, D.W.
1978-07-01
The authors prove that ground states of quantum spin systems are characterized by a principle of minimum local energy and that translationally invariant ground states are characterized by the principle of minimum energy per unit volume
Electric quadrupole strength in nuclei
International Nuclear Information System (INIS)
Kirson, M.W.
1979-01-01
Isoscalar electric quadrupole strength distributions in nuclei are surveyed, and it is concluded that the strength is shared, in most cases, roughly equally between low-lying transitions and the giant quadrupole state. The same is not true of the isovector case. A simple extension of the schematic model gives a remarkably successul description of the data, and emphasizes the vital importance of the coupling between high-lying and low-lying quadrupole modes. The standadrd simple representation of the giant quadrupole resonance as produced by operating on the nuclear ground state with the quadrupole transition operator is not applicable to the isoscalar case. It is suggested that giant resonances fall into broad classes of similar states, with considerable qualitative differences between the distinct classes. (author)
Line list for the ground state of CaF
Hou, Shilin; Bernath, Peter F.
2018-05-01
The molecular potential energy function and electronic dipole moment function for the ground state of CaF were studied with MRCI, ACPF, and RCCSD(T) ab initio calculations. The RCCSD(T) potential function reproduces the experimental vibrational intervals to within ∼2 cm-1. The RCCSD(T) dipole moment at the equilibrium internuclear separation agrees well with the experimental value. Over a wide range of internuclear separations, far beyond the range associated with the observed spectra, the ab initio dipole moment functions are similar and highly linear. An extended Morse oscillator (EMO) potential function was also obtained by fitting the observed lines of the laboratory vibration-rotation and pure rotation spectra of the 40CaF X2Σ+ ground state. The fitted potential reproduces the observed transitions (v ≤ 8, N ≤ 121, Δv = 0, 1) within their experimental uncertainties. With this EMO potential and the RCCSD(T) dipole moment function, line lists for 40CaF, 42CaF, 43CaF, 44CaF, 46CaF, and 48CaF were computed for v ≤ 10, N ≤ 121, Δv = 0-10. The calculated emission spectra are in good agreement with an observed laboratory spectrum of CaF at a sample temperature of 1873 K.
Ground state of the parallel double quantum dot system.
Zitko, Rok; Mravlje, Jernej; Haule, Kristjan
2012-02-10
We resolve the controversy regarding the ground state of the parallel double quantum dot system near half filling. The numerical renormalization group predicts an underscreened Kondo state with residual spin-1/2 magnetic moment, ln2 residual impurity entropy, and unitary conductance, while the Bethe ansatz solution predicts a fully screened impurity, regular Fermi-liquid ground state, and zero conductance. We calculate the impurity entropy of the system as a function of the temperature using the hybridization-expansion continuous-time quantum Monte Carlo technique, which is a numerically exact stochastic method, and find excellent agreement with the numerical renormalization group results. We show that the origin of the unconventional behavior in this model is the odd-symmetry "dark state" on the dots.
Centrifugal stretching along the ground state band of 168Hf
International Nuclear Information System (INIS)
Costin, A.; Pietralla, N.; Reese, M.; Moeller, O.; Ai, H.; Casten, R. F.; Heinz, A.; McCutchan, E. A.; Meyer, D. A.; Qian, J.; Werner, V.; Dusling, K.; Fitzpatrick, C. R.; Guerdal, G.; Petkov, P.; Rainovski, G.
2009-01-01
The lifetimes of the J π =4 + , 6 + , 8 + , and 10 + levels along the ground state band in 168 Hf were measured by means of the recoil distance Doppler shift (RDDS) method using the New Yale Plunger Device (NYPD) and the SPEEDY detection array at Wright Nuclear Structure Laboratory of Yale University. Excited states in 168 Hf were populated using the 124 Sn( 48 Ti,4n) fusion evaporation reaction. The new lifetime values are sufficiently precise to clearly prove the increase of quadrupole deformation as a function of angular momentum in the deformed nucleus 168 Hf. The data agree with the predictions from the geometrical confined β-soft (CBS) rotor model that involves centrifugal stretching in a soft potential
Consistent calculation of the polarization electric dipole moment by the shell-correction method
International Nuclear Information System (INIS)
Denisov, V.Yu.
1992-01-01
Macroscopic calculations of the polarization electric dipole moment which arises in nuclei with an octupole deformation are discussed in detail. This dipole moment is shown to depend on the position of the center of gravity. The conditions of consistency of the radii of the proton and neutron potentials and the radii of the proton and neutron surfaces, respectively, are discussed. These conditions must be incorporated in a shell-correction calculation of this dipole moment. A correct calculation of this moment by the shell-correction method is carried out. Dipole transitions between (on the one hand) levels belonging to an octupole vibrational band and (on the other) the ground state in rare-earth nuclei with a large quadrupole deformation are studied. 19 refs., 3 figs
Search for the QCD ground state
International Nuclear Information System (INIS)
Reuter, M.; Wetterich, C.
1994-05-01
Within the Euclidean effective action approach we propose criteria for the ground state of QCD. Despite a nonvanishing field strength the ground state should be invariant with respect to modified Poincare transformations consisting of a combination of translations and rotations with suitable gauge transformations. We have found candidate states for QCD with four or more colours. The formation of gluon condensates shows similarities with the Higgs phenomenon. (orig.)
Collective Quadrupole Excitations of Transactinide Nuclei
Zajac, K; Pomorski, K; Rohozinski, S G; Srebrny, J
2003-01-01
The quadrupole excitations of transuranic nuclei are described in the frame of the microscopic Bohr Hamiltonian modified by adding the coupling with the collective pairing vibrations. The energies of the states from the ground-state bands in U to No even-even isotopes as well as the B(E2) transition probabilities are reproduced within the model containing no adjustable parameters.
Measurement of nuclear moments and radii by collinear laser spectroscopy
Geithner, W R; Lievens, P; Kotrotsios, G; Silverans, R; Kappertz, S
2002-01-01
%IS304 %title\\\\ \\\\Collinear laser spectroscopy on a fast beam has proven to be a widely applicable and very efficient tool for measurements of changes in mean square nuclear charge radii, nuclear spins, magnetic dipole and electric quadrupole moments. Recent developments of extremely sensitive non-optical detection schemes enabled for some elements the extension of the measurements towards the very short-lived isotopes in the far wings of the ISOLDE production curves. The gain in sensitivity opens up new perspectives, particularly for measurements on lighter nuclei whose ground-state properties can be interpreted by large scale microscopic calculations instead of the more phenomenologic models used for heavier nuclei.\\\\ \\\\ For the sequence of argon isotopes $^{32-40}$Ar and $^{46}$Ar isotope shifts and nuclear moments were measured by optical pumping followed by state selective collisional ionization and detection of the $\\beta$-decay. Similarly, the low-background $\\alpha$-detection was used to extend earlie...
Energy Technology Data Exchange (ETDEWEB)
Nemoto, Yuichi [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan)]. E-mail: nemoto@phys.sc.niigata-u.ac.jp; Akatsu, Mitsuhiro [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Goto, Terutaka [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Suzuki, Osamu [National Institute for Materials Science, Tukuba 305-0003 (Japan); Nakamura, Shintaro [Center for Low Temperature Science, Tohoku University, Sendai 980-8577 (Japan); Kunii, Satoru [Department of Physics, Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan)
2005-04-30
We have performed low-temperature thermal expansion measurements to investigate lattice effect of the phase IV in Ce{sub x}La{sub 1-x}B{sub 6}, for x=0.75 and 0.70. In phase IV of both compounds, lattice length along the [111] direction shrinks notably, on the other hand length along the [001] direction expands. These results provide evidence that the spontaneous {gamma}{sub 5g} ferro-quadrupole moment
Unambiguous assignment of the ground state of a nearly degenerate cluster
International Nuclear Information System (INIS)
Gutsev, G. L.; Khanna, S. N.; Jena, P.
2000-01-01
A synergistic approach that combines first-principles theory and electron photodetachment experiment is shown to be able to uniquely identify the ground state of a nearly degenerate cluster in the gas phase. Additionally, this approach can complement the Stern-Gerlach technique in determining the magnetic moment of small clusters unambiguously. The method, applied to a Fe 3 cluster, reveals its ground state to have a magnetic moment of 10μ B --in contrast with earlier predictions. (c) 2000 The American Physical Society
A quantized microwave quadrupole insulator with topologically protected corner states
Peterson, Christopher W.; Benalcazar, Wladimir A.; Hughes, Taylor L.; Bahl, Gaurav
2018-03-01
The theory of electric polarization in crystals defines the dipole moment of an insulator in terms of a Berry phase (geometric phase) associated with its electronic ground state. This concept not only solves the long-standing puzzle of how to calculate dipole moments in crystals, but also explains topological band structures in insulators and superconductors, including the quantum anomalous Hall insulator and the quantum spin Hall insulator, as well as quantized adiabatic pumping processes. A recent theoretical study has extended the Berry phase framework to also account for higher electric multipole moments, revealing the existence of higher-order topological phases that have not previously been observed. Here we demonstrate experimentally a member of this predicted class of materials—a quantized quadrupole topological insulator—produced using a gigahertz-frequency reconfigurable microwave circuit. We confirm the non-trivial topological phase using spectroscopic measurements and by identifying corner states that result from the bulk topology. In addition, we test the critical prediction that these corner states are protected by the topology of the bulk, and are not due to surface artefacts, by deforming the edges of the crystal lattice from the topological to the trivial regime. Our results provide conclusive evidence of a unique form of robustness against disorder and deformation, which is characteristic of higher-order topological insulators.
Cavity optomechanics -- beyond the ground state
Meystre, Pierre
2011-05-01
The coupling of coherent optical systems to micromechanical devices, combined with breakthroughs in nanofabrication and in ultracold science, has opened up the exciting new field of cavity optomechanics. Cooling of the vibrational motion of a broad range on oscillating cantilevers and mirrors near their ground state has been demonstrated, and the ground state of at least one such system has now been reached. Cavity optomechanics offers much promise in addressing fundamental physics questions and in applications such as the detection of feeble forces and fields, or the coherent control of AMO systems and of nanoscale electromechanical devices. However, these applications require taking cavity optomechanics ``beyond the ground state.'' This includes the generation and detection of squeezed and other non-classical states, the transfer of squeezing between electromagnetic fields and motional quadratures, and the development of measurement schemes for the characterization of nanomechanical structures. The talk will present recent ``beyond ground state'' developments in cavity optomechanics. We will show how the magnetic coupling between a mechanical membrane and a BEC - or between a mechanical tuning fork and a nanoscale cantilever - permits to control and monitor the center-of-mass position of the mechanical system, and will comment on the measurement back-action on the membrane motion. We will also discuss of state transfer between optical and microwave fields and micromechanical devices. Work done in collaboration with Dan Goldbaum, Greg Phelps, Keith Schwab, Swati Singh, Steve Steinke, Mehmet Tesgin, and Mukund Vengallatore and supported by ARO, DARPA, NSF, and ONR.
Thermodynamic Ground States of Complex Oxide Heterointerfaces
DEFF Research Database (Denmark)
Gunkel, F.; Hoffmann-Eifert, S.; Heinen, R. A.
2017-01-01
The formation mechanism of 2-dimensional electron gases (2DEGs) at heterointerfaces between nominally insulating oxides is addressed with a thermodynamical approach. We provide a comprehensive analysis of the thermodynamic ground states of various 2DEG systems directly probed in high temperature...
Dewberry, C. T.; Grubbs, G. S.; Cooke, S. A.
2009-09-01
Using pulsed jet chirped-pulse, and cavity-based Fourier transform microwave spectroscopies over 900 transitions have been recorded for the title molecule in the 1-4 GHz and 8-18 GHz regions. The C,C and C carbon-13 species have been observed in natural abundance allowing a substitution structure for the CCC backbone to be determined. Nearly all the transitions observed were either a-type R branches or b-type Q branches. No c-type transitions were observed consistent with only the trans conformer being present under our experimental conditions. The χaa,χbb,χcc and χab components of the iodine nuclear quadrupole coupling tensor have been determined. Of note, several forbidden, ΔJ±2 transitions, and one ΔJ±3 transition were observed with quite reasonable intensity. These observations have been rationalized through considerations of near degeneracies between energy levels connected via a large χab value (≈1 GHz).
International Nuclear Information System (INIS)
Yu Lei; Liu Shuxin; Zeng Jinyan
2004-01-01
The microscopic mechanism of the variation with rotational frequency of moments of inertia and their odd-even differences for well-deformed actinide nuclei are analyzed by using the particle-number conserving (PNC) method for treating nuclear pairing interaction. The moments of inertia for bands building on high j intruder orbitals in odd-A nuclei, e.g., the 235 U (ν[743]7/2) band, are found to be much larger than those of ground-state bands in neighboring even-even nuclei. Moreover, there exist large odd-even differences in the ω variation of moments of inertia. All these experimental odd-even differences are reproduced quite well in the PNC calculation, in which the effective monopole and quadrupole pairing interaction strengths are determined by the experimental odd-even differences in binding energies and bandhead moments of inertia, and no free parameter is involved in the PNC calculation
Magnetostriction-driven ground-state stabilization in 2H perovskites
International Nuclear Information System (INIS)
Porter, D. G.; Senn, M. S.; University of Oxford; Khalyavin, D. D.; Cortese, A.
2016-01-01
In this paper, the magnetic ground state of Sr_3ARuO_6, with A =(Li,Na), is studied using neutron diffraction, resonant x-ray scattering, and laboratory characterization measurements of high-quality crystals. Combining these results allows us to observe the onset of long-range magnetic order and distinguish the symmetrically allowed magnetic models, identifying in-plane antiferromagnetic moments and a small ferromagnetic component along the c axis. While the existence of magnetic domains masks the particular in-plane direction of the moments, it has been possible to elucidate the ground state using symmetry considerations. We find that due to the lack of local anisotropy, antisymmetric exchange interactions control the magnetic order, first through structural distortions that couple to in-plane antiferromagnetic moments and second through a high-order magnetoelastic coupling that lifts the degeneracy of the in-plane moments. Finally, the symmetry considerations used to rationalize the magnetic ground state are very general and will apply to many systems in this family, such as Ca_3ARuO_6, with A = (Li,Na), and Ca_3LiOsO_6 whose magnetic ground states are still not completely understood.
Study of ground state optical transfer for ultracold alkali dimers
Bouloufa-Maafa, Nadia; Londono, Beatriz; Borsalino, Dimitri; Vexiau, Romain; Mahecha, Jorge; Dulieu, Olivier; Luc-Koenig, Eliane
2013-05-01
Control of molecular states by laser pulses offer promising potential applications. The manipulation of molecules by external fields requires precise knowledge of the molecular structure. Our motivation is to perform a detailed analysis of the spectroscopic properties of alkali dimers, with the aim to determine efficient optical paths to form molecules in the absolute ground state and to determine the optimal parameters of the optical lattices where those molecules are manipulated to avoid losses by collisions. To this end, we use state of the art molecular potentials, R-dependent spin-orbit coupling and transition dipole moment to perform our calculations. R-dependent SO coupling are of crucial importance because the transitions occur at internuclear distances where they are affected by this R-dependence. Efficient schemes to transfer RbCs, KRb and KCs to the absolute ground state as well as the optimal parameters of the optical lattices will be presented. This work was supported in part by ``Triangle de la Physique'' under contract 2008-007T-QCCM (Quantum Control of Cold Molecules).
Trapping cold ground state argon atoms.
Edmunds, P D; Barker, P F
2014-10-31
We trap cold, ground state argon atoms in a deep optical dipole trap produced by a buildup cavity. The atoms, which are a general source for the sympathetic cooling of molecules, are loaded in the trap by quenching them from a cloud of laser-cooled metastable argon atoms. Although the ground state atoms cannot be directly probed, we detect them by observing the collisional loss of cotrapped metastable argon atoms and determine an elastic cross section. Using a type of parametric loss spectroscopy we also determine the polarizability of the metastable 4s[3/2](2) state to be (7.3±1.1)×10(-39) C m(2)/V. Finally, Penning and associative losses of metastable atoms in the absence of light assisted collisions, are determined to be (3.3±0.8)×10(-10) cm(3) s(-1).
Magnetic properties of singlet ground state systems
International Nuclear Information System (INIS)
Diederix, K.M.
1979-01-01
Experiments are described determining the properties of a magnetic system consisting of a singlet ground state. Cu(NO 3 ) 2 .2 1/2H 2 O has been studied which is a system of S = 1/2 alternating antiferromagnetic Heisenberg chains. The static properties, spin lattice relaxation time and field-induced antiferromagnetically ordered state measurements are presented. Susceptibility and magnetic cooling measurements of other compounds are summarised. (Auth.)
Ground state searches in fcc intermetallics
International Nuclear Information System (INIS)
Wolverton, C.; de Fontaine, D.; Ceder, G.; Dreysse, H.
1991-12-01
A cluster expansion is used to predict the fcc ground states, i.e., the stable phases at zero Kelvin as a function of composition, for alloy systems. The intermetallic structures are not assumed, but derived regorously by minimizing the configurational energy subject to linear constraints. This ground state search includes pair and multiplet interactions which spatially extend to fourth nearest neighbor. A large number of these concentration-independent interactions are computed by the method of direct configurational averaging using a linearized-muffin-tin orbital Hamiltonian cast into tight binding form (TB-LMTO). The interactions, derived without the use of any adjustable or experimentally obtained parameters, are compared to those calculated via the generalized perturbation method extention of the coherent potential approximation within the context of a KKR Hamiltonian (KKR-CPA-GPM). Agreement with the KKR-CPA-GPM results is quite excellent, as is the comparison of the ground state results with the fcc-based portions of the experimentally-determined phase diagrams under consideration
DEFF Research Database (Denmark)
Severin, Gregory; Knutson, L. D.; Voytas, P. A.
2014-01-01
The ground state branch of the β decay of 66Ga is an allowed Fermi (0+ → 0+) transition with a relatively high f t value. The large f t and the isospin-forbidden nature of the transition indicates that the shape of the β spectrum of this branch may be sensitive to higher order contributions...... to the decay. Two previous measurements of the shape have revealed deviations from an allowed spectrum but disagree about whether the shape factor has a positive or negative slope. As a test of a new iron-free superconducting β spectrometer, we have measured the shape of the ground state branch of the 66Ga β...... spectrum above a positron energy of 1.9 MeV. The spectrum is consistent with an allowed shape, with the slope of the shape factor being zero to within ±3 × 10−3 per MeV. We have also determined the endpoint energy for the ground state branch to be 4.1535 ± 0.0003 (stat.) ±0.0007 (syst.) MeV, in good...
International Nuclear Information System (INIS)
Furukawa, Y.; Watanabe, K.; Kumagai, K.; Borsa, F.; Gatteschi, D.
2001-01-01
55 Mn nuclear magnetic resonance (NMR) measurements have been carried out in an oriented powder sample of Mn12 acetate at low temperature (1.4--3 K) in order to investigate locally the static and dynamic magnetic properties of the molecule in its high-spin S=10 ground state. We report the observation of three 55 MnNMR lines under zero external magnetic field. From the resonance frequency and the width of the lines we derive the internal hyperfine field and the quadrupole coupling constant at each of the three nonequivalent Mn ion sites. From the field dependence of the spectrum we obtain a direct confirmation of the standard picture, in which spin moments of Mn 4+ ions (S=3/2) of the inner tetrahedron are polarized antiparallel to that of Mn 3+ ions (S=2) of the outer ring with no measurable canting from the easy axis up to an applied field of 6 T. It is found that the splitting of the 55 Mn-NMR lines when a magnetic field is applied at low temperature allows one to monitor the off-equilibrium population of the molecules in the different low lying magnetic states. The measured nuclear spin-lattice relaxation time T 1 strongly depends on temperature and magnetic field. The behavior could be fitted well by considering the local-field fluctuations at the nuclear 55 Mn site due to the thermal reorientation of the total S=10 spin of the molecule. From the fit of the data one can derive the product of the spin-phonon coupling constant times the mean-square value of the fluctuating hyperfine field. The two constants could be estimated separately by making some assumptions. The comparison of the mean-square fluctuation from relaxation with the static hyperfine field from the spectrum suggests that nonuniform terms (q≠0) are important in describing the spin dynamics of the local Mn moments in the ground state
Traces of Lorentz symmetry breaking in a hydrogen atom at ground state
Borges, L. H. C.; Barone, F. A.
2016-02-01
Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schrödinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector.
Traces of Lorentz symmetry breaking in a hydrogen atom at ground state
Energy Technology Data Exchange (ETDEWEB)
Borges, L.H.C. [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas, Santo Andre, SP (Brazil); Barone, F.A. [IFQ-Universidade Federal de Itajuba, Itajuba, MG (Brazil)
2016-02-15
Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schroedinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector. (orig.)
Traces of Lorentz symmetry breaking in a hydrogen atom at ground state
International Nuclear Information System (INIS)
Borges, L.H.C.; Barone, F.A.
2016-01-01
Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schroedinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector. (orig.)
Variational approach to magnetic moments
Energy Technology Data Exchange (ETDEWEB)
Lipparini, E; Stringari, S; Traini, M [Dipartimento di Matematica e Fisica, Libera Universita di Trento, Italy
1977-11-07
Magnetic moments in nuclei with a spin unsaturated core plus or minus an extra nucleon have been studied using a restricted Hartree-Fock approach. The method yields simple explicit expressions for the deformed ground state and for magnetic moments. Different projection techniques of the HF scheme have been discussed and compared with perturbation theory.
Ground states of a spin-boson model
International Nuclear Information System (INIS)
Amann, A.
1991-01-01
Phase transition with respect to ground states of a spin-boson Hamiltonian are investigated. The spin-boson model under discussion consists of one spin and infinitely many bosons with a dipole-type coupling. It is shown that the order parameter of the model vanishes with respect to arbitrary ground states if it vanishes with respect to ground states obtained as (biased) temperature to zero limits of thermic equilibrium states. The ground states of the latter special type have been investigated by H. Spohn. Spohn's respective phase diagrams are therefore valid for arbitrary ground states. Furthermore, disjointness of ground states in the broken symmetry regime is examined
A Model Ground State of Polyampholytes
International Nuclear Information System (INIS)
Wofling, S.; Kantor, Y.
1998-01-01
The ground state of randomly charged polyampholytes (polymers with positive and negatively charged groups along their backbone) is conjectured to have a structure similar to a necklace, made of weakly charged parts of the chain, compacting into globules, connected by highly charged stretched 'strings' attempted to quantify the qualitative necklace model, by suggesting a zero approximation model, in which the longest neutral segment of the polyampholyte forms a globule, while the remaining part will form a tail. Expanding this approximation, we suggest a specific necklace-type structure for the ground state of randomly charged polyampholyte's, where all the neutral parts of the chain compact into globules: The longest neutral segment compacts into a globule; in the remaining part of the chain, the longest neutral segment (the second longest neutral segment) compacts into a globule, then the third, and so on. A random sequence of charges is equivalent to a random walk, and a neutral segment is equivalent to a loop inside the random walk. We use analytical and Monte Carlo methods to investigate the size distribution of loops in a one-dimensional random walk. We show that the length of the nth longest neutral segment in a sequence of N monomers (or equivalently, the nth longest loop in a random walk of N steps) is proportional to N/n 2 , while the mean number of neutral segments increases as √N. The polyampholytes in the ground state within our model is found to have an average linear size proportional to dN, and an average surface area proportional to N 2/3
RPA ground state correlations in nuclei
International Nuclear Information System (INIS)
Lenske, H.
1990-01-01
Overcounting in the RPA theory of ground state correlations is shown to be avoided if exact rather than quasiboson commutators are used. Single particle occupation probabilities are formulated in a compact way by the RPA Green function. Calculations with large configuration spaces and realistic interactions are performed with 1p1h RPA and second RPA (SRPA) including 2p2h mixing in excited states. In 41 Ca valence hole states are found to be quenched by about 10% in RPA and up to 18% in SRPA. Contributions from low and high lying excitations and their relation to long and short range correlations in finite nuclei are investigated. (orig.)
Ground-state structures of Hafnium clusters
Energy Technology Data Exchange (ETDEWEB)
Ng, Wei Chun; Yoon, Tiem Leong [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lim, Thong Leng [Faculty of Engineering and Technoloty, Multimedia University, Melaca Campus, 75450 Melaka (Malaysia)
2015-04-24
Hafnium (Hf) is a very large tetra-valence d-block element which is able to form relatively long covalent bond. Researchers are interested to search for substitution to silicon in the semi-conductor industry. We attempt to obtain the ground-state structures of small Hf clusters at both empirical and density-functional theory (DFT) levels. For calculations at the empirical level, charge-optimized many-body functional potential (COMB) is used. The lowest-energy structures are obtained via a novel global-minimum search algorithm known as parallel tempering Monte-Carlo Basin-Hopping and Genetic Algorithm (PTMBHGA). The virtue of using COMB potential for Hf cluster calculation lies in the fact that by including the charge optimization at the valence shells, we can encourage the formation of proper bond hybridization, and thus getting the correct bond order. The obtained structures are further optimized using DFT to ensure a close proximity to the ground-state.
Ground-State Band and Deformation of the Z = 102 Isotope N 254
International Nuclear Information System (INIS)
Reiter, P.; Khoo, T.L.; Lister, C.J.; Seweryniak, D.; Ahmad, I.; Alcorta, M.; Carpenter, M.P.; Cizewski, J.A.; Davids, C.N.; Gervais, G.; Greene, J.P.; Henning, W.F.; Janssens, R.V.; Lauritsen, T.; Siem, S.; Sonzogni, A.A.; Sullivan, D.; Uusitalo, J.; Wiedenhoever, I.; Amzal, N.; Butler, P.A.; Chewter, A.J.; Greenlees, P.T.; Herzberg, R.; Jones, G.D.; Cizewski, J.A.; Ding, K.Y.; Fotiades, N.; Fox, J.D.; Korten, W.; Leino, M.; Vetter, K.; Siem, S.
1999-01-01
The ground-state band of the Z=102 isotope 254 No has been identified up to spin 14, indicating that the nucleus is deformed. The deduced quadrupole deformation, β=0.27 , is in agreement with theoretical predictions. These observations confirm that the shell-correction energy responsible for the stability of transfermium nuclei is partly derived from deformation. The survival of 254 No up to spin 14 means that its fission barrier persists at least up to that spin. copyright 1999 The American Physical Society
Rotations as coherent states of SU(6) quadrupole phonons in the SU(3) limit
Energy Technology Data Exchange (ETDEWEB)
Canto, L F [Rio de Janeiro Univ. (Brazil). Inst. de Fisica; Paar, V [Zagreb Univ. (Yugoslavia). Prirodoslovno Matematicki Fakultet; Rio de Janeiro Univ. (Brazil). Inst. de Fisica)
1981-06-18
Analytic expressions for the wavefunctions of the ground-state rotational band for even and odd nuclei are derived in terms of spherical quadrupole phonons truncated at N(max) phonons. For N(max) ..-->.. infinite the Bohr-Mottelson rotational states are generated as an asymptotic gaussian distribution of quadrupole phonons.
Ground state of high-density matter
Copeland, ED; Kolb, Edward W.; Lee, Kimyeong
1988-01-01
It is shown that if an upper bound to the false vacuum energy of the electroweak Higgs potential is satisfied, the true ground state of high-density matter is not nuclear matter, or even strange-quark matter, but rather a non-topological soliton where the electroweak symmetry is exact and the fermions are massless. This possibility is examined in the standard SU(3) sub C tensor product SU(2) sub L tensor product U(1) sub Y model. The bound to the false vacuum energy is satisfied only for a narrow range of the Higgs boson masses in the minimal electroweak model (within about 10 eV of its minimum allowed value of 6.6 GeV) and a somewhat wider range for electroweak models with a non-minimal Higgs sector.
2D XXZ model ground state properties using an analytic Lanczos expansion
International Nuclear Information System (INIS)
Witte, N.S.; Hollenberg, L.C.L.; Weihong Zheng
1997-01-01
A formalism was developed for calculating arbitrary expectation values for any extensive lattice Hamiltonian system using a new analytic Lanczos expansion, or plaquette expansion, and a recently proved exact theorem for ground state energies. The ground state energy, staggered magnetisation and the excited state gap of the 2D anisotropic antiferromagnetic Heisenberg Model are then calculated using this expansion for a range of anisotropy parameters and compared to other moment based techniques, such as the t-expansion, and spin-wave theory and series expansion methods. It was found that far from the isotropic point all moment methods give essentially very similar results, but near the isotopic point the plaquette expansion is generally better than the others. 20 refs., 6 tabs
Ground-state properties of K-isotopes from laser and $\\beta$-NMR spectroscopy
Lievens, P; Rajabali, M M; Krieger, A R
By combining high-resolution laser spectroscopy with $\\beta$-NMR spectroscopy on polarized K-beams we aim to establish the ground-state spins and magnetic moments of the neutron-rich $^{48,49,50,51}$K isotopes from N=29 to N=32. Spins and magnetic moments of the odd-K isotopes up to N=28 reveal an inversion of the ground-state, from the normal $\\,{I}$=3/2 ($\\pi{d}_{3/2}^{-1}$) in $^{41-45}$K$\\to\\,{I}$=1/2 ($\\pi{s}_{1/2}^{-1}$) in $^{47}$K. This inversion of the proton single particle levels is related to the strong proton $d_{3/2}$ - neutron $f_{7/2}$ interaction which lowers the energy of the $\\pi{d}_{3/2}$ single particle state when filling the $\
Neutrino ground state in a dense star
International Nuclear Information System (INIS)
Kiers, K.; Tytgat, M.H.
1998-01-01
It has recently been argued that long range forces due to the exchange of massless neutrinos give rise to a very large self-energy in a dense, finite-ranged, weakly charged medium. Such an effect, if real, would destabilize a neutron star. To address this issue we have studied the related problem of a massless neutrino field in the presence of an external, static electroweak potential of finite range. To be precise, we have computed to one loop the exact vacuum energy for the case of a spherical square well potential of depth α and radius R. For small wells, the vacuum energy is reliably determined by a perturbative expansion in the external potential. For large wells, however, the perturbative expansion breaks down. A manifestation of this breakdown is that the vacuum carries a non-zero neutrino charge. The energy and neutrino charge of the ground state are, to a good approximation for large wells, those of a neutrino condensate with chemical potential μ=α. Our results demonstrate explicitly that long-range forces due to the exchange of massless neutrinos do not threaten the stability of neutron stars. copyright 1998 The American Physical Society
Electromagnetic properties of the three-nucleon ground state
International Nuclear Information System (INIS)
Strueve, W.
1985-01-01
The electromagnetic form factors of the three-nucleon ground state are calculated on the base of an exact solution of the Faddeev equations. In a Hilbert space of nucleons and a possible Δ-isobar the effects of a non-perturbative description of the Δ-isobar on the magnetic form factors are studied. Pure nucleonic current operators with two- and three-particle character can be described in the extended Hilbert space by simpler one-body operators. Additionally nonrelativistic meson-exchange corrections due to π and ρ exchange are calculated consistently with the requirements of current conservation. Further relativistic corrections are estimated on selected examples. The calculations yield a total magnetic contribution of the Δ-isobar which is smaller than hitherto assumed, a static approximation of the Δ propagation is proved as inadmissible and must be rejected. Together with the meson-exchange corrections a well agreement with the experimental data at low momentum transfers results. Especially the magnetic moments and magnetization radii can be explained. For higher momentum transfers the results show the importance of further corrections. The regard of selected relativistic corrections leads to a good description of the experimental magnetic form factors. Also by this way the position of the minimum and the height of the second maximum in the 3 He charge form factor can be explained. The comparison with the latest experimental results reveals furthermore unresolved problems in the description of the 3 H charge form factor. (orig.) [de
On the ground state of Yang-Mills theory
Bakry, Ahmed S.; Leinweber, Derek B.; Williams, Anthony G.
2011-01-01
We investigate the overlap of the ground state meson potential with sets of mesonic-trial wave functions corresponding to different gluonic distributions. We probe the transverse structure of the flux tube through the creation of non-uniform smearing profiles for the string of glue connecting two color sources in Wilson loop operator. The non-uniformly UV-regulated flux-tube operators are found to optimize the overlap with the ground state and display interesting features in the ground state ...
Is the ground state of Yang-Mills theory Coulombic?
Heinzl, Thomas; Ilderton, Anton; Langfeld, Kurt; Lavelle, Martin; Lutz, Wolfgang; McMullan, David
2008-01-01
We study trial states modelling the heavy quark-antiquark ground state in SU(2) Yang-Mills theory. A state describing the flux tube between quarks as a thin string of glue is found to be a poor description of the continuum ground state; the infinitesimal thickness of the string leads to UV artifacts which suppress the overlap with the ground state. Contrastingly, a state which surrounds the quarks with non-abelian Coulomb fields is found to have a good overlap with the ground state for all ch...
Nuclear electric quadrupole interactions in liquids entrapped in cavities
Energy Technology Data Exchange (ETDEWEB)
Furman, Gregory B., E-mail: gregoryf@bgu.ac.il; Meerovich, Victor M.; Sokolovsky, Vladimir L. [Ben Gurion University of the Negev, Physics Department (Israel)
2016-12-15
Liquids entrapped in cavities and containing quadrupole nuclei are considered. The interaction of the quadrupole moment of a nucleus with the electric field gradient is studied. In such a system, molecules are in both rotational and translational Brownian motions which are described by the diffusion equation. Solving this equation, we show that the intra- and intermolecular nuclear quadrupole interactions are averaged to zero in cavities with the size larger than several angstroms.
Solving satisfiability problems by the ground-state quantum computer
International Nuclear Information System (INIS)
Mao Wenjin
2005-01-01
A quantum algorithm is proposed to solve the satisfiability (SAT) problems by the ground-state quantum computer. The scale of the energy gap of the ground-state quantum computer is analyzed for the 3-bit exact cover problem. The time cost of this algorithm on the general SAT problems is discussed
Ground state phase diagram of extended attractive Hubbard model
International Nuclear Information System (INIS)
Robaszkiewicz, S.; Chao, K.A.; Micnas, R.
1980-08-01
The ground state phase diagram of the extended Hubbard model with intraatomic attraction has been derived in the Hartree-Fock approximation formulated in terms of the Bogoliubov variational approach. For a given value of electron density, the nature of the ordered ground state depends essentially on the sign and the strength of the nearest neighbor coupling. (author)
Is the ground state of Yang-Mills theory Coulombic?
Heinzl, T.; Ilderton, A.; Langfeld, K.; Lavelle, M.; Lutz, W.; McMullan, D.
2008-08-01
We study trial states modelling the heavy quark-antiquark ground state in SU(2) Yang-Mills theory. A state describing the flux tube between quarks as a thin string of glue is found to be a poor description of the continuum ground state; the infinitesimal thickness of the string leads to UV artifacts which suppress the overlap with the ground state. Contrastingly, a state which surrounds the quarks with non-Abelian Coulomb fields is found to have a good overlap with the ground state for all charge separations. In fact, the overlap increases as the lattice regulator is removed. This opens up the possibility that the Coulomb state is the true ground state in the continuum limit.
On the ground state of Yang-Mills theory
International Nuclear Information System (INIS)
Bakry, Ahmed S.; Leinweber, Derek B.; Williams, Anthony G.
2011-01-01
Highlights: → The ground state overlap for sets of meson potential trial states is measured. → Non-uniform gluonic distributions are probed via Wilson loop operator. → The locally UV-regulated flux-tube operators can optimize the ground state overlap. - Abstract: We investigate the overlap of the ground state meson potential with sets of mesonic-trial wave functions corresponding to different gluonic distributions. We probe the transverse structure of the flux tube through the creation of non-uniform smearing profiles for the string of glue connecting two color sources in Wilson loop operator. The non-uniformly UV-regulated flux-tube operators are found to optimize the overlap with the ground state and display interesting features in the ground state overlap.
Ground-state properties of axially deformed Sr isotopes in Skyrme-Hartree-Fock-Bogolyubov method
International Nuclear Information System (INIS)
Yilmaz, A.H.; Bayram, T.; Demirci, M.; Engin, B.; Bayram, T.
2010-01-01
Binding energies, the mean-square nuclear radii, neutron radii, quadrupole moments and deformation parameters to axially deformed Strontium isotopes were evaluated using Hartree-Fock-Bogolyubov method. Shape coexistence was also discussed. The results were compared with experimental data and some estimates obtained within some nuclear models. The calculations were performed for SIy4 set of Skyrme forces and for wide range of the neutron numbers of Sr isotopes
Towards the measurement of the ground-state hyperfine splitting of antihydrogen
Energy Technology Data Exchange (ETDEWEB)
Juhasz, Bertalan, E-mail: bertalan.juhasz@oeaw.ac.at [Austrian Academy of Sciences, Stefan Meyer Institute for Subatomic Physics (Austria)
2012-12-15
The ASACUSA collaboration at the Antiproton Decelerator of CERN is planning to measure the ground-state hyperfine splitting of antihydrogen using an atomic beam line, which will consist of a superconducting cusp trap as a source of partially polarized antihydrogen atoms, a radiofrequency spin-flip cavity, a superconducting sextupole magnet as spin analyser, and an antihydrogen detector. This will be a measurement of the antiproton magnetic moment, and also a test of the CPT invariance. Monte Carlo simulations predict that the antihydrogen ground-state hyperfine splitting can be determined with a relative precision of better than {approx} 10{sup - 6}. The first preliminary measurements of the hyperfine transitions will start in 2011.
Study of polonium isotopes ground state properties by simultaneous atomic- and nuclear-spectroscopy
Koester, U H; Kalaninova, Z; Imai, N
2007-01-01
We propose to systematically study the ground state properties of neutron deficient $^{192-200}$Po isotopes by means of in-source laser spectroscopy using the ISOLDE laser ion source coupled with nuclear spectroscopy at the detection setup as successfully done before by this collaboration with neutron deficient lead isotopes. The study of the change in mean square charge radii along the polonium isotope chain will give an insight into shape coexistence above the mid-shell N = 104 and above the closed shell Z = 82. The hyperfine structure of the odd isotopes will also allow determination of the nuclear spin and the magnetic moment of the ground state and of any identifiable isomer state. For this study, a standard UC$_{x}$ target with the ISOLDE RILIS is required for 38 shifts.
Energy Technology Data Exchange (ETDEWEB)
Michael Ramsey-Musolf; Wick Haxton; Ching-Pang Liu
2002-03-29
Nuclear anapole moments are parity-odd, time-reversal-even E1 moments of the electromagnetic current operator. Although the existence of this moment was recognized theoretically soon after the discovery of parity nonconservation (PNC), its experimental isolation was achieved only recently, when a new level of precision was reached in a measurement of the hyperfine dependence of atomic PNC in 133Cs. An important anapole moment bound in 205Tl also exists. In this paper, we present the details of the first calculation of these anapole moments in the framework commonly used in other studies of hadronic PNC, a meson exchange potential that includes long-range pion exchange and enough degrees of freedom to describe the five independent S-P amplitudes induced by short-range interactions. The resulting contributions of pi-, rho-, and omega-exchange to the single-nucleon anapole moment, to parity admixtures in the nuclear ground state, and to PNC exchange currents are evaluated, using configuration-mixed shell-model wave functions. The experimental anapole moment constraints on the PNC meson-nucleon coupling constants are derived and compared with those from other tests of the hadronic weak interaction. While the bounds obtained from the anapole moment results are consistent with the broad ''reasonable ranges'' defined by theory, they are not in good agreement with the constraints from the other experiments. We explore possible explanations for the discrepancy and comment on the potential importance of new experiments.
International Nuclear Information System (INIS)
Michael Ramsey-Musolf; Wick Haxton; Ching-Pang Liu
2002-01-01
Nuclear anapole moments are parity-odd, time-reversal-even E1 moments of the electromagnetic current operator. Although the existence of this moment was recognized theoretically soon after the discovery of parity nonconservation (PNC), its experimental isolation was achieved only recently, when a new level of precision was reached in a measurement of the hyperfine dependence of atomic PNC in 133Cs. An important anapole moment bound in 205Tl also exists. In this paper, we present the details of the first calculation of these anapole moments in the framework commonly used in other studies of hadronic PNC, a meson exchange potential that includes long-range pion exchange and enough degrees of freedom to describe the five independent S-P amplitudes induced by short-range interactions. The resulting contributions of pi-, rho-, and omega-exchange to the single-nucleon anapole moment, to parity admixtures in the nuclear ground state, and to PNC exchange currents are evaluated, using configuration-mixed shell-model wave functions. The experimental anapole moment constraints on the PNC meson-nucleon coupling constants are derived and compared with those from other tests of the hadronic weak interaction. While the bounds obtained from the anapole moment results are consistent with the broad ''reasonable ranges'' defined by theory, they are not in good agreement with the constraints from the other experiments. We explore possible explanations for the discrepancy and comment on the potential importance of new experiments
Spins, moments and radii of Cd isotopes
International Nuclear Information System (INIS)
Hammen, Michael
2013-01-01
The complex nature of the nucleon-nucleon interaction and the wide range of systems covered by the roughly 3000 known nuclides leads to a multitude of effects observed in nuclear structure. Among the most prominent ones is the occurence of shell closures at so-called ''magic numbers'', which are explained by the nuclear shell model. Although the shell model already is on duty for several decades, it is still constantly extended and improved. For this process of extension, fine adjustment and verification, it is important to have experimental data of nuclear properties, especially at crucial points like in the vicinity of shell closures. This is the motivation for the work performed in this thesis: the measurement and analysis of nuclear ground state properties of the isotopic chain of 100-130 Cd by collinear laser spectroscopy. The experiment was conducted at ISOLDE/CERN using the collinear laser spectroscopy apparatus COLLAPS. This experiment is the continuation of a run on neutral atomic cadmium from A = 106 to A = 126 and extends the measured isotopes to even more exotic species. The required gain in sensitivity is mainly achieved by using a radiofrequency cooler and buncher for background reduction and by using the strong 5s 2 S 1/2 →5p 2 P 3/2 transition in singly ionized Cd. The latter requires a continuous wave laser system with a wavelength of 214.6 nm, which has been developed during this thesis. Fourth harmonic generation of an infrared titanium sapphire laser is achieved by two subsequent cavity-enhanced second harmonic generations, leading to the production of deep-UV laser light up to about 100 mW. The acquired data of the Z=48 Cd isotopes, having one proton pair less than the Z=50 shell closure at tin, covers the isotopes from N=52 up to N=82 and therefore almost the complete region between the neutron shell closures N=50 and N=82. The isotope shifts and the hyperfine structures of these isotopes have been recorded and the magnetic dipole moments
Spins, moments and radii of Cd isotopes
Energy Technology Data Exchange (ETDEWEB)
Hammen, Michael
2013-10-30
The complex nature of the nucleon-nucleon interaction and the wide range of systems covered by the roughly 3000 known nuclides leads to a multitude of effects observed in nuclear structure. Among the most prominent ones is the occurence of shell closures at so-called ''magic numbers'', which are explained by the nuclear shell model. Although the shell model already is on duty for several decades, it is still constantly extended and improved. For this process of extension, fine adjustment and verification, it is important to have experimental data of nuclear properties, especially at crucial points like in the vicinity of shell closures. This is the motivation for the work performed in this thesis: the measurement and analysis of nuclear ground state properties of the isotopic chain of {sup 100-130}Cd by collinear laser spectroscopy. The experiment was conducted at ISOLDE/CERN using the collinear laser spectroscopy apparatus COLLAPS. This experiment is the continuation of a run on neutral atomic cadmium from A = 106 to A = 126 and extends the measured isotopes to even more exotic species. The required gain in sensitivity is mainly achieved by using a radiofrequency cooler and buncher for background reduction and by using the strong 5s {sup 2}S{sub 1/2}→5p{sup 2}P{sub 3/2} transition in singly ionized Cd. The latter requires a continuous wave laser system with a wavelength of 214.6 nm, which has been developed during this thesis. Fourth harmonic generation of an infrared titanium sapphire laser is achieved by two subsequent cavity-enhanced second harmonic generations, leading to the production of deep-UV laser light up to about 100 mW. The acquired data of the Z=48 Cd isotopes, having one proton pair less than the Z=50 shell closure at tin, covers the isotopes from N=52 up to N=82 and therefore almost the complete region between the neutron shell closures N=50 and N=82. The isotope shifts and the hyperfine structures of these isotopes have been
Directory of Open Access Journals (Sweden)
Akrawy Dashty T.
2018-01-01
Full Text Available Theoretical α-decay half-lives of some nuclei from ground state to ground state are calculated using different nuclear potential model including Coulomb proximity potential (CPPM, Royer proximity potential and Broglia and Winther 1991. The calculated values comparing with experimental data, it is observed that the CPPM model is in good agreement with the experimental data.
Classical many-particle systems with unique disordered ground states
Zhang, G.; Stillinger, F. H.; Torquato, S.
2017-10-01
Classical ground states (global energy-minimizing configurations) of many-particle systems are typically unique crystalline structures, implying zero enumeration entropy of distinct patterns (aside from trivial symmetry operations). By contrast, the few previously known disordered classical ground states of many-particle systems are all high-entropy (highly degenerate) states. Here we show computationally that our recently proposed "perfect-glass" many-particle model [Sci. Rep. 6, 36963 (2016), 10.1038/srep36963] possesses disordered classical ground states with a zero entropy: a highly counterintuitive situation . For all of the system sizes, parameters, and space dimensions that we have numerically investigated, the disordered ground states are unique such that they can always be superposed onto each other or their mirror image. At low energies, the density of states obtained from simulations matches those calculated from the harmonic approximation near a single ground state, further confirming ground-state uniqueness. Our discovery provides singular examples in which entropy and disorder are at odds with one another. The zero-entropy ground states provide a unique perspective on the celebrated Kauzmann-entropy crisis in which the extrapolated entropy of a supercooled liquid drops below that of the crystal. We expect that our disordered unique patterns to be of value in fields beyond glass physics, including applications in cryptography as pseudorandom functions with tunable computational complexity.
On the ground state of Yang-Mills theory
Bakry, Ahmed S.; Leinweber, Derek B.; Williams, Anthony G.
2011-08-01
We investigate the overlap of the ground state meson potential with sets of mesonic-trial wave functions corresponding to different gluonic distributions. We probe the transverse structure of the flux tube through the creation of non-uniform smearing profiles for the string of glue connecting two color sources in Wilson loop operator. The non-uniformly UV-regulated flux-tube operators are found to optimize the overlap with the ground state and display interesting features in the ground state overlap.
Light-cone distribution amplitudes of the ground state bottom baryons in HQET
Energy Technology Data Exchange (ETDEWEB)
Ali, A.; Wang, W. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Hambrock, C. [Technische Univ. Dortmund (Germany); Parkhomenko, A.Ya. [P.G. Demidov Yaroslavl State Univ., Yaroslavl (Russian Federation)
2012-12-15
We provide the definition of the complete set of light-cone distribution amplitudes (LCDAs) for the ground state heavy bottom baryons with the spin-parities J{sup P}=1/2{sup +} and J{sup P}=3/2{sup +} in the heavy quark limit. We present the renormalization effects on the twist-2 light-cone distribution amplitudes and use the QCD sum rules to compute the moments of twist-2, twist-3, and twist-4 LCDAs. Simple models for the heavy baryon distribution amplitudes are analyzed with account of their scale dependence.
Ground State Energy of the Modified Nambu-Goto String
Hadasz, Leszek
We calculate, using zeta function regularization method, semiclassical energy of the Nambu-Goto string supplemented with the boundary, Gauss-Bonnet term in the action and discuss the tachyonic ground state problem.
Ground state energy of the modified Nambu-Goto string
Hadasz, Leszek
1997-01-01
We calculate, using zeta function regularization method, semiclassical energy of the Nambu-Goto string supplemented with the boundary, Gauss-Bonnet term in the action and discuss the tachyonic ground state problem.
Approximating the ground state of gapped quantum spin systems
Energy Technology Data Exchange (ETDEWEB)
Michalakis, Spyridon [Los Alamos National Laboratory; Hamza, Eman [NON LANL; Nachtergaele, Bruno [NON LANL; Sims, Robert [NON LANL
2009-01-01
We consider quantum spin systems defined on finite sets V equipped with a metric. In typical examples, V is a large, but finite subset of Z{sup d}. For finite range Hamiltonians with uniformly bounded interaction terms and a unique, gapped ground state, we demonstrate a locality property of the corresponding ground state projector. In such systems, this ground state projector can be approximated by the product of observables with quantifiable supports. In fact, given any subset {chi} {contained_in} V the ground state projector can be approximated by the product of two projections, one supported on {chi} and one supported on {chi}{sup c}, and a bounded observable supported on a boundary region in such a way that as the boundary region increases, the approximation becomes better. Such an approximation was useful in proving an area law in one dimension, and this result corresponds to a multi-dimensional analogue.
On the ground state for fractional quantum hall effect
International Nuclear Information System (INIS)
Jellal, A.
1998-09-01
In the present letter, we investigate the ground state wave function for an explicit model of electrons in an external magnetic field with specific inter-particle interactions. The excitation states of this model are also given. (author)
The ground state energy of a classical gas
International Nuclear Information System (INIS)
Conlon, J.G.
1983-01-01
The ground state energy of a classical gas is treated using a probability function for the position of the particles and a potential function. The lower boundary for the energy when the particle number is large is defined as ground state energy. The coulomb gas consisting of positive and negative particles is also treated (fixed and variable density case) the stability of the relativistic system is investigated as well. (H.B.)
Theory of ground state factorization in quantum cooperative systems.
Giampaolo, Salvatore M; Adesso, Gerardo; Illuminati, Fabrizio
2008-05-16
We introduce a general analytic approach to the study of factorization points and factorized ground states in quantum cooperative systems. The method allows us to determine rigorously the existence, location, and exact form of separable ground states in a large variety of, generally nonexactly solvable, spin models belonging to different universality classes. The theory applies to translationally invariant systems, irrespective of spatial dimensionality, and for spin-spin interactions of arbitrary range.
Ground state energy fluctuations in the nuclear shell model
International Nuclear Information System (INIS)
Velazquez, Victor; Hirsch, Jorge G.; Frank, Alejandro; Barea, Jose; Zuker, Andres P.
2005-01-01
Statistical fluctuations of the nuclear ground state energies are estimated using shell model calculations in which particles in the valence shells interact through well-defined forces, and are coupled to an upper shell governed by random 2-body interactions. Induced ground-state energy fluctuations are found to be one order of magnitude smaller than those previously associated with chaotic components, in close agreement with independent perturbative estimates based on the spreading widths of excited states
On calculations of the ground state energy in quantum mechanics
International Nuclear Information System (INIS)
Efimov, G.V.
1991-02-01
In nonrelativistic quantum mechanics the Wick-ordering method called the oscillator representation suggested to calculate the ground-state energy for a wide class of potentials allowing the existence of a bound state. The following examples are considered: the orbital excitations of the ground-state in the Coulomb plus linear potential, the Schroedinger equation with a ''relativistic'' kinetic energy √p 2 +m 2 , the Coulomb three-body problem. (author). 22 refs, 2 tabs
Kinetic energy in the collective quadrupole Hamiltonian from the experimental data
Energy Technology Data Exchange (ETDEWEB)
Jolos, R.V., E-mail: jolos@theor.jinr.ru [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Dubna State University, 141980 Dubna (Russian Federation); Kolganova, E.A. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Dubna State University, 141980 Dubna (Russian Federation)
2017-06-10
Dependence of the kinetic energy term of the collective nuclear Hamiltonian on collective momentum is considered. It is shown that the fourth order in collective momentum term of the collective quadrupole Hamiltonian generates a sizable effect on the excitation energies and the matrix elements of the quadrupole moment operator. It is demonstrated that the results of calculation are sensitive to the values of some matrix elements of the quadrupole moment. It stresses the importance for a concrete nucleus to have the experimental data for the reduced matrix elements of the quadrupole moment operator taken between all low lying states with the angular momenta not exceeding 4.
Electromagnetic moments and electric dipole transitions in carbon isotopes
International Nuclear Information System (INIS)
Suzuki, Toshio; Sagawa, Hiroyuki; Hagino, Kouichi
2003-01-01
We carry out shell model calculations to study electromagnetic moments and electric dipole transitions of C isotopes. We point out the configuration dependence of the quadrupole and magnetic moments of the odd C isotopes, which will be useful to find out the deformations and the spin parities of the ground states of these nuclei. We also study the electric dipole states of C isotopes, focusing on the interplay between low energy pigmy strength and giant dipole resonances. As far as the energies of the resonances are concerned, reasonable agreement is obtained with available experimental data for the photoreaction cross sections in 12 C, 13 C, and 14 C, both in the low energy region below (ℎ/2π)ω=14 MeV and in the high energy giant resonance region (14 MeV 15 C is found to exhaust about 12-16 % of the classical Thomas-Reiche-Kuhn sum rule value and 50-80 % of the cluster sum rule value
ISABELLE insertion quadrupoles
International Nuclear Information System (INIS)
Kaugerts, J.; Polk, I.; Sampson, W.; Dahl, P.F.
1979-01-01
Beam focussing and control at the beam intersection regions of ISABELLE is accomplished by a number of superconducting insertion quadrupoles. These magnets differ from the standard ISABELLE quadrupoles in various ways. In particular, the requirements of limited space near the intersections and aperture for beam extraction impose constraints on their configuration. To achieve optimum beam focussing and provide tuning flexibility calls for stronger quadrupole trim windings than those in the standard quadrupoles. The magnetic and mechanical design of the insertion quadrupoles and their associated correction and steering windings to accomplish the above tasks is presented
AUTHOR|(CDS)2083426
The hyperfine structure of the odd-even $^{51−63}$Mn isotopes (N = 26 − 38) were measured using bunched beam collinear laser spectroscopy with the COLLAPS experimental setup at ISOLDE, CERN. The properties of these nuclei were investigated over the course of two experiments. During the first experiment, nuclear spins and magnetic dipole moments were extracted from spectroscopy on manganese atoms. These nuclear properties were then compared to the predictions of two large-scale shell model effective interactions (GXPF1A [1, 2] and LNPS [3]) which use different model spaces. In the case of $^{61,63}$Mn, these results show the increasing importance of neutron excitations across the proposed N = 40 subshell closure, and of proton excitations across the Z = 28 shell gap. These measurements provide the first direct proof that proton and neutron excitations across shell gaps are playing an important role in the ground state wave functions of the neutron-rich Mn isotopes. The electric quadrupole moment provides c...
Initial value gravitational quadrupole radiation theorem
International Nuclear Information System (INIS)
Winicour, J.
1987-01-01
A rigorous version of the quadrupole radiation formula is derived using the characteristic initial value formulation of a general relativistic fluid space-time. Starting from initial data for a Newtonian fluid, an algorithm is presented that determines characteristic initial data for a one-parameter family of general relativistic fluid space-times. At the initial time, a one-parameter family of space-times with this initial data osculates the evolution of the Newtonian fluid and has leading order news function equal to the third time derivative of the transverse Newtonian quadrupole moment
International Nuclear Information System (INIS)
Flocard, H.
1975-04-01
Hartree-Fock results concerning the ground state properties of some S-D shell nuclei are discussed. Two different Skyrme interactions have been used. They both lead to good agreement with the experimental total binding energies, charge radii and multipole moments. In particular the observed prolate-oblate transitions occuring in the S-D shell are reproduced. The calculated spectroscopic factors are also shown to be consistent with experimental data [fr
Towards 6Li-40K ground state molecules
International Nuclear Information System (INIS)
Brachmann, Johannes Felix Simon
2013-01-01
The production of a quantum gas with strong long - range dipolar interactions is a major scientific goal in the research field of ultracold gases. In their ro - vibrational ground state Li-K dimers possess a large permanent dipole moment, which could possibly be exploited for the realization of such a quantum gas. A production of these molecules can be achieved by the association of Li and K at a Feshbach resonance, followed by a coherent state transfer. In this thesis, detailed theoretical an experimental preparations to achieve state transfer by means of Stimulated Raman Adiabatic Passage (STIRAP) are described. The theoretical preparations focus on the selection of an electronically excited molecular state that is suitable for STIRAP transfer. In this context, molecular transition dipole moments for both transitions involved in STIRAP transfer are predicted for the first time. This is achieved by the calculation of Franck-Condon factors and a determination of the state in which the 6 Li- 40 K Feshbach molecules are produced. The calculations show that state transfer by use of a single STIRAP sequence is experimentally very well feasible. Further, the optical wavelengths that are needed to address the selected states are calculated. The high accuracy of the data will allow to carry out the molecular spectroscopy in a fast and efficient manner. Further, only a comparatively narrow wavelength tuneability of the spectroscopy lasers is needed. The most suitable Feshbach resonance for the production of 6 Li- 40 K molecules at experimentally manageable magnetic field strengths is occurring at 155 G. Experimentally, this resonance is investigated by means of cross-dimensional relaxation. The application of the technique at various magnetic field strengths in the vicinity of the 155 G Feshbach resonance allows a determination of the resonance position and width with so far unreached precision. This reveals the production of molecules on the atomic side of the resonance
Probing quantum frustrated systems via factorization of the ground state.
Giampaolo, Salvatore M; Adesso, Gerardo; Illuminati, Fabrizio
2010-05-21
The existence of definite orders in frustrated quantum systems is related rigorously to the occurrence of fully factorized ground states below a threshold value of the frustration. Ground-state separability thus provides a natural measure of frustration: strongly frustrated systems are those that cannot accommodate for classical-like solutions. The exact form of the factorized ground states and the critical frustration are determined for various classes of nonexactly solvable spin models with different spatial ranges of the interactions. For weak frustration, the existence of disentangling transitions determines the range of applicability of mean-field descriptions in biological and physical problems such as stochastic gene expression and the stability of long-period modulated structures.
Ground-state fidelity in the BCS-BEC crossover
International Nuclear Information System (INIS)
Khan, Ayan; Pieri, Pierbiagio
2009-01-01
The ground-state fidelity has been introduced recently as a tool to investigate quantum phase transitions. Here, we apply this concept in the context of a crossover problem. Specifically, we calculate the fidelity susceptibility for the BCS ground-state wave function, when the intensity of the fermionic attraction is varied from weak to strong in an interacting Fermi system, through the BCS-Bose-Einstein Condensation crossover. Results are presented for contact and finite-range attractive potentials and for both continuum and lattice models. We conclude that the fidelity susceptibility can be useful also in the context of crossover problems.
Ground state correlations and structure of odd spherical nuclei
International Nuclear Information System (INIS)
Mishev, S.; Voronov, V. V.
2006-01-01
It is well known that the Pauli principle plays a substantial role at low energies because the phonon operators are not ideal boson operators. Calculating the exact commutators between the quasiparticle and phonon operators one can take into account the Pauli principle corrections. Besides the ground state correlations due to the quasiparticle interaction in the ground state influence the single particle fragmentation as well. In this paper, we generalize the basic QPM equations to account for both mentioned effects. As an illustration of our approach, calculations on the structure of the low-lying states in "1"3"1Ba have been performed.
Ground state correlations and structure of odd spherical nuclei
International Nuclear Information System (INIS)
Mishev, S.; Voronov, V.V.
2008-01-01
It is well known that the Pauli principle plays a substantial role at low energies because the phonon operators are not ideal boson operators. Calculating the exact commutators between the quasiparticle and phonon operators one can take into account the Pauli principle corrections. Besides, the ground state correlations due to the quasiparticle interaction in the ground state influence the single-particle fragmentation as well. In this paper, we generalize the basic equations of the quasiparticle-phonon nuclear model to account for both effects mentioned. As an illustration of our approach, calculations on the structure of the low-lying states in 133 Ba have been performed
Ground-state electronic structure of actinide monocarbides and mononitrides
DEFF Research Database (Denmark)
Petit, Leon; Svane, Axel; Szotek, Z.
2009-01-01
The self-interaction corrected local spin-density approximation is used to investigate the ground-state valency configuration of the actinide ions in the actinide monocarbides, AC (A=U,Np,Pu,Am,Cm), and the actinide mononitrides, AN. The electronic structure is characterized by a gradually increa...
A Ground State Tri-pí-Methane Rearrangement
Czech Academy of Sciences Publication Activity Database
Zimmerman, H. E.; Církva, Vladimír; Jiang, L.
2000-01-01
Roč. 41, č. 49 (2000), s. 9585-9587 ISSN 0040-4039 Institutional research plan: CEZ:AV0Z4072921 Keywords : tri-pi-methane * ground state Subject RIV: CC - Organic Chemistry Impact factor: 2.558, year: 2000
Calculations of the ground state of 16O
International Nuclear Information System (INIS)
Pieper, S.C.
1989-01-01
One of the central problems in nuclear physics is the description of nuclei as systems of nucleons interacting via realistic potentials. There are two main aspects of this problem: specification of the Hamiltonian, and calculation of the ground states of nuclei with the given interaction. Realistic interactions must contain both two- and three-nucleon potentials and these potentials have a complicated non-central operator structure consisting, for example, of spin, isospin and tensor dependences. This structure results in formidable many-body problems in the computation of the ground states of nuclei. At present, reliable solutions of the Faddeev equations for the A = 3 nuclei with such interactions are routine. Recently, Carlson has made an essentially exact GFMC calculation of the He ground state using just a two-nucleon interaction, and there are reliable variational calculations for more complete potential models. Nuclear matter calculations can also be made with reasonable reliability. However, there have been very few calculations of nuclei with A > 5 using realistic interactions, and none with a modern three-nucleon interaction. In the present paper I present a new technique for variational calculations for such nuclei and apply it to the ground state of 16 O. 15 refs., 2 figs., 3 tabs
Ground state energy of a polaron in a superlattice
International Nuclear Information System (INIS)
Mensah, S.Y.; Allotey, F.K.A.; Nkrumah, G.; Mensah, N.G.
2000-10-01
The ground state energy of a polaron in a superlattice was calculated using the double-time Green functions. The effective mass of the polaron along the planes perpendicular to the superlattice axis was also calculated. The dependence of the ground state energy and the effective mass along the planes perpendicular to the superlattice axis on the electron-phonon coupling constant α and on the superlattice parameters (i.e. the superlattice period d and the bandwidth Δ) were studied. It was observed that if an infinite square well potential is assumed, the ground state energy of the polaron decreases (i.e. becomes more negative) with increasing α and d, but increases with increasing Δ. For small values of α, the polaron ground state energy varies slowly with Δ, becoming approximately constant for large Δ. The effective mass along the planes perpendicular to the superlattice axis was found to be approximately equal to the mass of an electron for all typical values of α, d and Δ. (author)
Observation of Hyperfine Transitions in Trapped Ground-State Antihydrogen
Olin, Arthur
2015-01-01
This paper discusses the first observation of stimulated magnetic resonance transitions between the hyperfine levels of trapped ground state atomic antihydrogen, confirming its presence in the ALPHA apparatus. Our observations show that these transitions are consistent with the values in hydrogen to within 4~parts~in~$10^3$. Simulations of the trapped antiatoms in a microwave field are consistent with our measurements.
Search for C+ C clustering in Mg ground state
Indian Academy of Sciences (India)
2017-01-04
Jan 4, 2017 ... Finite-range knockout theory predictions were much larger for (12C,212C) reaction, indicating a very small 12C−12C clustering in 24Mg. (g.s.) . Our present results contradict most of the proposed heavy cluster (12C+12C) structure models for the ground state of 24Mg. Keywords. Direct nuclear reactions ...
Fast Preparation of Critical Ground States Using Superluminal Fronts
Agarwal, Kartiek; Bhatt, R. N.; Sondhi, S. L.
2018-05-01
We propose a spatiotemporal quench protocol that allows for the fast preparation of ground states of gapless models with Lorentz invariance. Assuming the system initially resides in the ground state of a corresponding massive model, we show that a superluminally moving "front" that locally quenches the mass, leaves behind it (in space) a state arbitrarily close to the ground state of the gapless model. Importantly, our protocol takes time O (L ) to produce the ground state of a system of size ˜Ld (d spatial dimensions), while a fully adiabatic protocol requires time ˜O (L2) to produce a state with exponential accuracy in L . The physics of the dynamical problem can be understood in terms of relativistic rarefaction of excitations generated by the mass front. We provide proof of concept by solving the proposed quench exactly for a system of free bosons in arbitrary dimensions, and for free fermions in d =1 . We discuss the role of interactions and UV effects on the free-theory idealization, before numerically illustrating the usefulness of the approach via simulations on the quantum Heisenberg spin chain.
Entanglement of two ground state neutral atoms using Rydberg blockade
DEFF Research Database (Denmark)
Miroshnychenko, Yevhen; Browaeys, Antoine; Evellin, Charles
2011-01-01
We report on our recent progress in trapping and manipulation of internal states of single neutral rubidium atoms in optical tweezers. We demonstrate the creation of an entangled state between two ground state atoms trapped in separate tweezers using the effect of Rydberg blockade. The quality...... of the entanglement is measured using global rotations of the internal states of both atoms....
α-clustering in the ground state of 40Ca
International Nuclear Information System (INIS)
Michel, F.
1976-01-01
The anomalous large angle scattering observed in 40 Ca(α, α) is studied in the frame of a semi-microscopic model taking into account the presence of α-correlations in the ground state of 40 Ca. The calculations, performed between 18 and 29 MeV, assert the potential, non resonant nature of the phenomenon. (Auth.)
Ground states of the massless Derezinski-Gerard model
International Nuclear Information System (INIS)
Ohkubo, Atsushi
2009-01-01
We consider the massless Derezinski-Gerard model introduced by Derezinski and Gerard in 1999. We give a sufficient condition for the existence of a ground state of the massless Derezinski-Gerard model without the assumption that the Hamiltonian of particles has compact resolvent.
Magnetic excitons in singlet-ground-state ferromagnets
DEFF Research Database (Denmark)
Birgeneau, R.J.; Als-Nielsen, Jens Aage; Bucher, E.
1971-01-01
The authors report measurements of the dispersion of singlet-triplet magnetic excitons as a function of temperature in the singlet-ground-state ferromagnets fcc Pr and Pr3Tl. Well-defined excitons are observed in both the ferromagnetic and paramagnetic regions, but with energies which are nearly...
Correlation induced paramagnetic ground state in FeAl
Czech Academy of Sciences Publication Activity Database
Mohn, P.; Persson, C.; Blaha, P.; Schwarz, K.; Novák, Pavel; Eschrig, H.
2001-01-01
Roč. 87, č. 19 (2001), s. 196401-1-196401-4 ISSN 0031-9007 Institutional research plan: CEZ:AV0Z1010914 Keywords : FeAl * paramagnetic ground state Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 6.668, year: 2001
Observation of hyperfine transitions in trapped ground-state antihydrogen
Energy Technology Data Exchange (ETDEWEB)
Collaboration: A. Olin for the ALPHA Collaboration
2015-08-15
This paper discusses the first observation of stimulated magnetic resonance transitions between the hyperfine levels of trapped ground state atomic antihydrogen, confirming its presence in the ALPHA apparatus. Our observations show that these transitions are consistent with the values in hydrogen to within 4 parts in 10{sup 3}. Simulations of the trapped antiatoms in a microwave field are consistent with our measurements.
Centering of quadrupole family
International Nuclear Information System (INIS)
Pinayev, Igor
2007-01-01
A procedure for finding the individual centers for a family of quadrupoles fed with a single power supply is described. The method is generalized for using the correctors adjacent to the quadrupoles. Theoretical background is presented as well as experimental data for the NSLS rings. The method accuracy is also discussed
Antiferrodistortive phase transitions and ground state of PZT ceramics
International Nuclear Information System (INIS)
Pandey, Dhananjai
2013-01-01
The ground state of the technologically important Pb(Zr x Ti (1-x) )O 3 , commonly known as PZT, ceramics is currently under intense debate. The phase diagram of this material shows a morphotropic phase boundary (MPB) for x∼0.52 at 300K, across which a composition induced structural phase transition occurs leading to maximization of the piezoelectric properties. In search for the true ground state of the PZT in the MPB region, Beatrix Noheda and coworkers first discovered a phase transition from tetragonal (space group P4mm) to an M A type monoclinic phase (space group Cm) at low temperatures for x=0.52. Soon afterwards, we discovered yet another low temperature phase transition for the same composition in which the M A type (Cm) monoclinic phase transforms to another monoclinic phase with Cc space group. We have shown that the Cm to Cc phase transition is an antiferrodistortive (AFD) transition involving tilting of oxygen octahedra leading to unit cell doubling and causing appearance of superlattice reflections which are observable in the electron and neutron diffraction patterns only and not in the XRD patterns, as a result of which Noheda and coworkers missed the Cc phase in their synchrotron XRD studies at low temperatures. Our findings were confirmed by leading groups using neutron, TEM, Raman and high pressure diffraction studies. The first principles calculations also confirmed that the true ground state of PZT in the MPB region has Cc space group. However, in the last couple of years, the Cc space group of the ground state has become controversial with an alternative proposal of R3c as the space group of the ground state phase which is proposed to coexist with the metastable Cm phase. In order to resolve this controversy, we recently revisited the issue using pure PZT and 6% Sr 2+ substituted PZT, the latter samples show larger tilt angle on account of the reduction in the average cationic radius at the Pb 2+ site. Using high wavelength neutrons and high
Gross shell structure of moments of inertia
International Nuclear Information System (INIS)
Deleplanque, M.A.; Frauendorf, S.; Pashkevich, V.V.; Chu, S.Y.; Unzhakova, A.
2002-01-01
Average yrast moments of inertia at high spins, where the pairing correlations are expected to be largely absent, were found to deviate from the rigid-body values. This indicates that shell effects contribute to the moment of inertia. We discuss the gross dependence of moments of inertia and shell energies on the neutron number in terms of the semiclassical periodic orbit theory. We show that the ground-state shell energies, nuclear deformations and deviations from rigid-body moments of inertia are all due to the same periodic orbits
International Nuclear Information System (INIS)
Towner, I.S.; Khanna, F.C.
1984-01-01
Consideration of core polarization, isobar currents and meson-exchange processes gives a satisfactory understanding of the ground-state magnetic moments in closed-shell-plus (or minus)-one nuclei, A = 3, 15, 17, 39 and 41. Ever since the earliest days of the nuclear shell model the understanding of magnetic moments of nuclear states of supposedly simple configurations, such as doubly closed LS shells +-1 nucleon, has been a challenge for theorists. The experimental moments, which in most cases are known with extraordinary precision, show a small yet significant departure from the single-particle Schmidt values. The departure, however, is difficult to evaluate precisely since, as will be seen, it results from a sensitive cancellation between several competing corrections each of which can be as large as the observed discrepancy. This, then, is the continuing fascination of magnetic moments. In this contribution, we revisit the subjet principally to identify the role played by isobar currents, which are of much concern at this conference. But in so doing we warn quite strongly of the dangers of considering just isobar currents in isolation; equal consideration must be given to competing processes which in this context are the mundane nuclear structure effects, such as core polarization, and the more popular meson-exchange currents
Superconducting magnetic quadrupole
Energy Technology Data Exchange (ETDEWEB)
Kim, J.W.; Shepard, K.W.; Nolen, J.A.
1995-08-01
A design was developed for a 350 T/m, 2.6-cm clear aperture superconducting quadrupole focussing element for use in a very low q/m superconducting linac as discussed below. The quadrupole incorporates holmium pole tips, and a rectangular-section winding using standard commercially-available Nb-Ti wire. The magnet was modeled numerically using both 2D and 3D codes, as a basis for numerical ray tracing using the quadrupole as a linac element. Components for a prototype singlet are being procured during FY 1995.
Cluster expansion for ground states of local Hamiltonians
Directory of Open Access Journals (Sweden)
Alvise Bastianello
2016-08-01
Full Text Available A central problem in many-body quantum physics is the determination of the ground state of a thermodynamically large physical system. We construct a cluster expansion for ground states of local Hamiltonians, which naturally incorporates physical requirements inherited by locality as conditions on its cluster amplitudes. Applying a diagrammatic technique we derive the relation of these amplitudes to thermodynamic quantities and local observables. Moreover we derive a set of functional equations that determine the cluster amplitudes for a general Hamiltonian, verify the consistency with perturbation theory and discuss non-perturbative approaches. Lastly we verify the persistence of locality features of the cluster expansion under unitary evolution with a local Hamiltonian and provide applications to out-of-equilibrium problems: a simplified proof of equilibration to the GGE and a cumulant expansion for the statistics of work, for an interacting-to-free quantum quench.
Coherent Control of Ground State NaK Molecules
Yan, Zoe; Park, Jee Woo; Loh, Huanqian; Will, Sebastian; Zwierlein, Martin
2016-05-01
Ultracold dipolar molecules exhibit anisotropic, tunable, long-range interactions, making them attractive for the study of novel states of matter and quantum information processing. We demonstrate the creation and control of 23 Na40 K molecules in their rovibronic and hyperfine ground state. By applying microwaves, we drive coherent Rabi oscillations of spin-polarized molecules between the rotational ground state (J=0) and J=1. The control afforded by microwave manipulation allows us to pursue engineered dipolar interactions via microwave dressing. By driving a two-photon transition, we are also able to observe Ramsey fringes between different J=0 hyperfine states, with coherence times as long as 0.5s. The realization of long coherence times between different molecular states is crucial for applications in quantum information processing. NSF, AFOSR- MURI, Alfred P. Sloan Foundation, DARPA-OLE
Ground-state properties of a supersymmetric fermion chain
International Nuclear Information System (INIS)
Fendley, Paul; Hagendorf, Christian
2011-01-01
We analyze the ground state of a strongly interacting fermion chain with a supersymmetry. We conjecture a number of exact results, such as a hidden duality between weak and strong couplings. By exploiting a scale-free property of the perturbative expansions, we find exact expressions for the order parameters, yielding the critical exponents. We show that the ground state of this fermion chain and another model in the same universality class, the XYZ chain along a line of couplings, are both written in terms of the same polynomials. We demonstrate this explicitly for up to N = 24 sites and provide consistency checks for large N. These polynomials satisfy a recursion relation related to the Painlevé VI differential equation and, using a scale-free property of these polynomials, we derive a simple and exact formula for their N→∞ limit
Dissociation energy of the ground state of NaH
International Nuclear Information System (INIS)
Huang, Hsien-Yu; Lu, Tsai-Lien; Whang, Thou-Jen; Chang, Yung-Yung; Tsai, Chin-Chun
2010-01-01
The dissociation energy of the ground state of NaH was determined by analyzing the observed near dissociation rovibrational levels. These levels were reached by stimulated emission pumping and fluorescence depletion spectroscopy. A total of 114 rovibrational levels in the ranges 9≤v '' ≤21 and 1≤J '' ≤14 were assigned to the X 1 Σ + state of NaH. The highest vibrational level observed was only about 40 cm -1 from the dissociation limit in the ground state. One quasibound state, above the dissociation limit and confined by the centrifugal barrier, was observed. Determining the vibrational quantum number at dissociation v D from the highest four vibrational levels yielded the dissociation energy D e =15 815±5 cm -1 . Based on new observations and available data, a set of Dunham coefficients and the rotationless Rydberg-Klein-Rees curve were constructed. The effective potential curve and the quasibound states were discussed.
Three-body problem in the ground-state representation
International Nuclear Information System (INIS)
Gonzalez, A.
1993-01-01
The ground-state probability density of a three-body system is used to construct a classical potential U whose minimum coincides exactly with the ground-state energy. The spectrum of excited states may approximately be obtained by imposing quasiclassical quantization conditions over the classical motion in U. We show nontrivial one-dimensional models in which either this quantization condition is exact or considerably improves the usual semiclassical quantization. For three-dimensional problems, the small-oscillation frequencies in states with total angular momentum L = 0 are computed. These frequencies could represent an improvement over the frequencies of triatomic molecules computed with the use of ordinary quasiclassics for the motion of the nuclei in the molecular term. By providing a semiclassical description of the first excited quantum states, the sketched approach rises some interesting questions such as, for example, the relevance (once again) of classical chaos to quantum mechanics
Variational calculation for the ground state of 12C
International Nuclear Information System (INIS)
Consoni, L.H.A.; Coelho, H.T.; Das, T.K.
1983-01-01
A variational calculation is done for the ground state of a 3α-particle system. Two simple trial wavefunctions are used and results are compared with an exact calculation done by the Hyperspherical Harmonic method. A modifed Ali-Bodmer potential for the α-α interaction is considered for all calculations. It is found that these simple wave functions can be very useful for phenomenological calculations. (Author) [pt
Bethe ansatz study for ground state of Fateev Zamolodchikov model
International Nuclear Information System (INIS)
Ray, S.
1997-01-01
A Bethe ansatz study of a self-dual Z N spin lattice model, originally proposed by V. A. Fateev and A. B. Zamolodchikov, is undertaken. The connection of this model to the Chiral Potts model is established. Transcendental equations connecting the zeros of Fateev endash Zamolodchikov transfer matrix are derived. The free energies for the ferromagnetic and the anti-ferromagnetic ground states are found for both even and odd spins. copyright 1997 American Institute of Physics
Ground-state correlations within a nonperturbative approach
Czech Academy of Sciences Publication Activity Database
De Gregorio, G.; Herko, J.; Knapp, F.; Lo Iudice, N.; Veselý, Petr
2017-01-01
Roč. 95, č. 2 (2017), č. článku 024306. ISSN 2469-9985 R&D Projects: GA ČR GA13-07117S Institutional support: RVO:61389005 Keywords : ground state * harmonic oscillator frequency * space dimensions Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 3.820, year: 2016
Ground state solutions for non-local fractional Schrodinger equations
Directory of Open Access Journals (Sweden)
Yang Pu
2015-08-01
Full Text Available In this article, we study a time-independent fractional Schrodinger equation with non-local (regional diffusion $$ (-\\Delta^{\\alpha}_{\\rho}u + V(xu = f(x,u \\quad \\text{in }\\mathbb{R}^{N}, $$ where $\\alpha \\in (0,1$, $N > 2\\alpha$. We establish the existence of a non-negative ground state solution by variational methods.
Electronic and ground state properties of ThTe
Energy Technology Data Exchange (ETDEWEB)
Bhardwaj, Purvee, E-mail: purveebhardwaj@gmail.com; Singh, Sadhna, E-mail: drsadhna100@gmail.com [High Pressure Research Lab. Department of Physics Barkatullah University, Bhopal (MP) 462026 (India)
2016-05-06
The electronic properties of ThTe in cesium chloride (CsCl, B2) structure are investigated in the present paper. To study the ground state properties of thorium chalcogenide, the first principle calculations have been calculated. The bulk properties, including lattice constant, bulk modulus and its pressure derivative are obtained. The calculated equilibrium structural parameters are in good agreement with the available experimental and theoretical results.
Ground states for light and heavy quark hadrons
Energy Technology Data Exchange (ETDEWEB)
Anderson, J T [Physics Dept., Philippines Univ., Manila (Philippines)
1994-01-01
According to de Rujula et al. if the degenerate multiplet masses are known then it is not necessary to parametrize the interactions. With degenerate multiplet masses calculated from the spinorial decomposition of the SU(2)xSU(2) part of the SU(6)xSU(6) symmetry, the ground states for 3, 4 and 5 quark hadrons are calculated in terms of the Cartan matrix integers n[sub [alpha
Ground state solutions for diffusion system with superlinear nonlinearity
Directory of Open Access Journals (Sweden)
Zhiming Luo
2015-03-01
where $z=(u,v\\colon\\mathbb{R}\\times\\mathbb{R}^{N}\\rightarrow\\mathbb{R}^{2}$, $b\\in C^{1}(\\mathbb{R}\\times\\mathbb{R}^{N}, \\mathbb{R}^{N}$ and $V(x\\in C(\\mathbb{R}^{N},\\mathbb{R}$. Under suitable assumptions on the nonlinearity, we establish the existence of ground state solutions by the generalized Nehari manifold method developed recently by Szulkin and Weth.
Ground state and elementary excitations of a model valence-fluctuation system
International Nuclear Information System (INIS)
Brandow, B.H.
1979-01-01
The nature of the valence fluctuation problem is described, and motivations are given for an Anderson-lattice model Hamiltonian. A simple trial wave function is posed for the ground state, and the variational problem is solved. This demonstrates clearly that there is no Kondo-like divergence; the present concentrated Kondo problem is thus more simple mathematically than the sngle-impurity problem. Elementary excitations are studies by the Green's function techniques of Zubarev and Hubbard. Quenching of local moments and a large specific heat are found at low temperatures. The quasi-particle spectrum exhibits a gap, but epsilon/sub F/ does not lie in this gap. The insulation-like feature of SmB 6 , SmS, and TmSe at very low temperatures is explained in terms of a strongly reduced mobility for states near the gap, and reasons are given why this feature is not observed in other valence-fluctuation compounds. 73 references
Indian Academy of Sciences (India)
to do precision spectroscopic measurements on these ions. ... Bonn, investigated the non-magnetic quadrupole mass filter, .... the details of which will be discussed in the subse- ... the radial plane the ion undergoes a circular motion with the.
1974-01-01
A stack of SPS Quadrupole Magnets ready for installation in the tunnel. The SPS uses a total of 216 laminated normal conducting lattice quadrupoles with a length of 3.13 m for the core, 3.3 m overall. The F and D quads. have identical characteristics: inscribed circle radius 44 mm, core height and width 800 mm, maximum gradient 20 Tesla/m.
Observation of a phononic quadrupole topological insulator
Serra-Garcia, Marc; Peri, Valerio; Süsstrunk, Roman; Bilal, Osama R.; Larsen, Tom; Villanueva, Luis Guillermo; Huber, Sebastian D.
2018-03-01
The modern theory of charge polarization in solids is based on a generalization of Berry’s phase. The possibility of the quantization of this phase arising from parallel transport in momentum space is essential to our understanding of systems with topological band structures. Although based on the concept of charge polarization, this same theory can also be used to characterize the Bloch bands of neutral bosonic systems such as photonic or phononic crystals. The theory of this quantized polarization has recently been extended from the dipole moment to higher multipole moments. In particular, a two-dimensional quantized quadrupole insulator is predicted to have gapped yet topological one-dimensional edge modes, which stabilize zero-dimensional in-gap corner states. However, such a state of matter has not previously been observed experimentally. Here we report measurements of a phononic quadrupole topological insulator. We experimentally characterize the bulk, edge and corner physics of a mechanical metamaterial (a material with tailored mechanical properties) and find the predicted gapped edge and in-gap corner states. We corroborate our findings by comparing the mechanical properties of a topologically non-trivial system to samples in other phases that are predicted by the quadrupole theory. These topological corner states are an important stepping stone to the experimental realization of topologically protected wave guides in higher dimensions, and thereby open up a new path for the design of metamaterials.
2002-01-01
We aim at establishing an unambiguous spin determination of the ground and isomeric states in the neutron rich Cu-isotopes from A=72 up to A=78 and to measure the magnetic and quadrupole moments between the N=28 and N=50 shell closures. This study will provide information on the double-magicity of $^{56}$Ni and $^{78}$Ni, both at the extremes of nuclear stability. It will provide evidence on the suggested inversion of ground state spin around A$\\approx$74, due to the monopole migration of the $\\pi f_{5/2}$ level. The collinear laser spectroscopy technique will be used, which furthermore provides information on the changes in mean square charge radii between both neutron shell closures, probing a possible onset of deformation in this region.
Hartree–Fock variational bounds for ground state energy of ...
Indian Academy of Sciences (India)
volume V0, with mass m, electric charge zero, and magnetic moment μ, interacting through magnetic dipole–dipole ... like neutrinos, with finite magnetic dipole moment has not drawn too much at- tention. In an earlier .... to its value in the equatorial kx − ky plane for the same value of the magnitude of the wave vector. Note ...
Sideband cooling of micromechanical motion to the quantum ground state.
Teufel, J D; Donner, T; Li, Dale; Harlow, J W; Allman, M S; Cicak, K; Sirois, A J; Whittaker, J D; Lehnert, K W; Simmonds, R W
2011-07-06
The advent of laser cooling techniques revolutionized the study of many atomic-scale systems, fuelling progress towards quantum computing with trapped ions and generating new states of matter with Bose-Einstein condensates. Analogous cooling techniques can provide a general and flexible method of preparing macroscopic objects in their motional ground state. Cavity optomechanical or electromechanical systems achieve sideband cooling through the strong interaction between light and motion. However, entering the quantum regime--in which a system has less than a single quantum of motion--has been difficult because sideband cooling has not sufficiently overwhelmed the coupling of low-frequency mechanical systems to their hot environments. Here we demonstrate sideband cooling of an approximately 10-MHz micromechanical oscillator to the quantum ground state. This achievement required a large electromechanical interaction, which was obtained by embedding a micromechanical membrane into a superconducting microwave resonant circuit. To verify the cooling of the membrane motion to a phonon occupation of 0.34 ± 0.05 phonons, we perform a near-Heisenberg-limited position measurement within (5.1 ± 0.4)h/2π, where h is Planck's constant. Furthermore, our device exhibits strong coupling, allowing coherent exchange of microwave photons and mechanical phonons. Simultaneously achieving strong coupling, ground state preparation and efficient measurement sets the stage for rapid advances in the control and detection of non-classical states of motion, possibly even testing quantum theory itself in the unexplored region of larger size and mass. Because mechanical oscillators can couple to light of any frequency, they could also serve as a unique intermediary for transferring quantum information between microwave and optical domains.
Ground-State Structures of Ice at High-Pressures
McMahon, Jeffrey M.
2011-01-01
\\textit{Ab initio} random structure searching based on density functional theory is used to determine the ground-state structures of ice at high pressures. Including estimates of lattice zero-point energies, ice is found to adopt three novel crystal phases. The underlying sub-lattice of O atoms remains similar among them, and the transitions can be characterized by reorganizations of the hydrogen bonds. The symmetric hydrogen bonds of ice X and $Pbcm$ are initially lost as ice transforms to s...
Spectroscopic factor of the 7He ground state
International Nuclear Information System (INIS)
Beck, F.; Frekers, D.; Neumann-Cosel, P. von; Richter, A.; Ryezayeva, N.; Thompson, I.J.
2007-01-01
The neutron spectroscopic factor S n of the 7 He ground state is extracted from an R-matrix analysis of a recent measurement of the 7 Li(d, 2 He) 7 He reaction with good energy resolution. The width extracted from a deconvolution of the spectrum is Γ=183(22) keV (full width at half maximum, FWHM). The result S n =0.64(9) is slightly larger than predictions of recent 'ab initio' Green's function Monte Carlo and fermionic molecular dynamics calculations
Kohn-Sham Theory for Ground-State Ensembles
International Nuclear Information System (INIS)
Ullrich, C. A.; Kohn, W.
2001-01-01
An electron density distribution n(r) which can be represented by that of a single-determinant ground state of noninteracting electrons in an external potential v(r) is called pure-state v -representable (P-VR). Most physical electronic systems are P-VR. Systems which require a weighted sum of several such determinants to represent their density are called ensemble v -representable (E-VR). This paper develops formal Kohn-Sham equations for E-VR physical systems, using the appropriate coupling constant integration. It also derives local density- and generalized gradient approximations, and conditions and corrections specific to ensembles
Quadrupolar order, hidden octupolar order and tiny magnetic moment in URu2Si2
International Nuclear Information System (INIS)
Tsuruta, Atsushi; Matsuura, Tamifusa; Kuroda, Yoshihiro
2000-01-01
Possible orders in URu 2 Si 2 are investigated using a two-channel degenerate Anderson model. The ground state of uranium ions is the non-Kramers quadrupolar doublet Γ 5 with (5f) 2 , and its relevant excited state is the Kramers dipolar doublet Γ 7 with (5f) 1 . These states mix with each other via conduction electrons. At low temperatures, the system forms renormalized bands with both quadrupole and dipole degrees of freedom due to the quadrupolar Kondo effect which slightly mixes quadrupolar Γ 5 , a primary state of uranium ions, with dipolar Γ 7 . At a certain low temperature, conduction electrons in the renormalized bands undergo quadrupolar ordering with a large quadrupolar moment. At a further lower temperature, octupolar ordering occurs, accompanied by a tiny dipolar moment which is attributed to the property of the renormalized bands with primarily the Γ 5 -character slightly mixed with the Γ 7 -character. These phenomena are well described by the 1/N-expansion method with pseudo-fermions for the non-Kramers doublet Γ 5 and slave bosons for the Kramers doublet Γ 7 . (author)
International Nuclear Information System (INIS)
Bush, E.D. Jr.
1976-01-01
A family of quadrupole magnets using a soft iron return yoke and circular cross-section permanent magnet poles were fabricated to investigate the feasibility for use in ion or electron beam focusing applications in accelerators and transport lines. Magnetic field measurements yielded promising results. In fixed-field applications, permanent magnets with sufficient gradients would be a low cost substitute for conventional electromagnets, eliminating the need for power supplies, associated wiring, and cooling. Based on preliminary tests, it was seen that permanent quadrupole magnets can offer a low cost, reliable solution in applications requiring small, fixed-field focusing devices for use in ion or electron-beam transport systems. Permanent magnets do require special considerations in design, fabrication, handling, and service that are different than encountered in conventional quadrupole magnets. If these basic conditions are satisfied, the resulting beam-focusing device would be stable, maintenance free, with virtually an indefinite lifetime
Cluster decay of Ba isotopes from ground state and as an excited ...
Indian Academy of Sciences (India)
otherwise, inclusion of excitation energy decreases the T1/2 values. ... penetrates the nuclear barrier and reaches scission configuration after running .... between the ground-state energy levels of the parent nuclei and the ground-state energy.
A new representation for ground states and its Legendre transforms
International Nuclear Information System (INIS)
Cedillo, A.
1994-01-01
The ground-state energy of an electronic system is a functional of the number of electrons (N) and the external potential (v): E = E(N,V), this is the energy representation for ground states. In 1982, Nalewajski defined the Legendre transforms of this representation, taking advantage of the strict concavity of E with respect to their variables (concave respect v and convex respect N), and he also constructed a scheme for the reduction of derivatives of his representations. Unfortunately, N and the electronic density (p) were the independent variables of one of these representations, but p depends explicitly on N. In this work, this problem is avoided using the energy per particle (ε) as the basic variables, and the Legendre transformations can be defined. A procedure for the reduction of derivatives is generated for the new four representations and, in contrast to the Nalewajski's procedure, it only includes derivatives of the four representations. Finally, the reduction of derivatives is used to test some relationships between the hardness and softness kernels
International Nuclear Information System (INIS)
Terlain, Anne
1984-01-01
The 2D (two-dimensional) phase transitions and orientational order in N 2 O, CO 2 , C 2 N 2 and C 2 D 2 films physi-sorbed on the (0001) face of graphite or lamellar halides, were studied experimentally by adsorption isotherm measurements and neutron diffraction. The thermodynamic functions derived from sets of isotherms suggest that crystal monolayers of N 2 O, CO 2 , and C 2 N 2 adsorbed on graphite are orientationally ordered and that the quadrupolar interaction stabilizes the 2D crystal with respect to the 2D liquid. This stabilization leads to an increase in the 2D triple point temperature, T 2t as compared with the 2D critical temperature T 2c . For C 2 N 2 this stabilization is so pronounced that T 2t becomes virtually higher than T 2c , and the phase diagram qualitatively different, having no gas-liquid coexistence domain. From a neutron diffraction experiment we have determined the crystal structure of the C 2 N 2 monolayer. It supports our interpretation of the monolayer phase diagram. In N 2 O, CO 2 , C 2 N 2 films adsorbed on graphite the molecules lie flat on the surface and their orientational order hence differs from that in the bulk crystals resulting in a loss of adsorbate-adsorbate interaction energy. Beyond a given film thickness this loss will not be compensated by the adsorbate-substrate interaction and the film will stop growing. For most of the films studied a partial wetting transition is observed at which the film thickness increases discontinuously with temperature. Although C 2 N 2 and C 2 D 2 monolayers on graphite have comparable adsorption energies, only C 2 D 2 is adsorbed on lamellar halides. This adsorption is possible only because the monolayer has a large entropy due to orientational disorder. For C 2 N 2 , which has a higher moment of inertia, such an orientational disorder cannot exist. (author) [fr
Can the magnetic moment contribution explain the Ay puzzle?
International Nuclear Information System (INIS)
Stoks, V.G.
1998-01-01
We evaluate the full one-photon-exchange Born amplitude for Nd scattering. We include the contributions due to the magnetic moment of the proton or neutron, and the magnetic moment and quadrupole moment of the deuteron. It is found that the inclusion of the magnetic-moment interaction in the theoretical description of the Nd scattering observables cannot resolve the long-standing A y puzzle. copyright 1998 The American Physical Society
Torres del Castillo, G.F; Méndez Garrido, A
2006-01-01
Making use of the fact that a 2l-pole can be represented by means of l vectors of the same magnitude, the torque on a quadrupole in an inhomogeneous external field is expressed in terms of the vectors that represent the quadrupole and the gradient of the external field. The conditions for rotational equilibrium are also expressed in terms of these vectors. Haciendo uso de que un multipolo de orden 2l puede representarse mediante l vectores de la misma magnitud, la torca sobre un cuadripolo...
High gradient superconducting quadrupoles
International Nuclear Information System (INIS)
Lundy, R.A.; Brown, B.C.; Carson, J.A.; Fisk, H.E.; Hanft, R.H.; Mantsch, P.M.; McInturff, A.D.; Remsbottom, R.H.
1987-07-01
Prototype superconducting quadrupoles with a 5 cm aperture and gradient of 16 kG/cm have been built and tested as candidate magnets for the final focus at SLC. The magnets are made from NbTi Tevatron style cable with 10 inner and 14 outer turns per quadrant. Quench performance and multipole data are presented. Design and data for a low current, high gradient quadrupole, similar in cross section but wound with a cable consisting of five insulated conductors are also discussed
International Nuclear Information System (INIS)
Bredbacka, A.; Brenner, M.; Malik, F.B.; Aabo Akademi, Turku
1989-01-01
Properties of low-lying positive- and negative-parity states of 97,99,101,103,105,107,109 Rh at low excitation energies have been analyzed in terms of a Coriolis coupling model. The model can account for the general trend of the level schemes for states of both parties. In particular, the 9/2, 7/2, and 5/2 triplet near the ground state, the occurrence of multiple 13/2 and at least one 15/2 and 19/2 state of positive parity are reasonably reproduced by the model. Similarly, 1/2 ground-state spin followed by a (3/2, 5/2) doublet, and one or more 13/2 and 17/2 states of negative parity are adequately understood in terms of the model. The calculated electromagnetic dipole and quadrupole moments and magnetic dipole and electric quadrupole transition rates are in broad agreement with the observed ones. This is achieved without the use of any effective charge. The general trend of observed spectroscopic factors for pick-up reactions is in agreement with the calculated ones. The results are presented as a function of deformation. Because of the sparsity of data on many of these isotopes, no attempt has been made to find the best fit for each isotope individually. Since the model can reasonably reproduce the general trend of level schemes, electromagnetic properties and spectroscopic factors, one may conclude that the Coriolis coupling model provides a good description of the nuclear properties of these isotopes. (orig.)
The relation between the (N) and (N-1) electrons atomic ground state
International Nuclear Information System (INIS)
Briet, P.
1984-05-01
The relation between the ground state of an N and (N-1) electrons atomic system are studied. We show that in some directions of the configuration space, the ratio of the N electrons atomic ground state to the one particle density is asymptotically equivalent to the (N-1) electrons atomic ground state
Ground state magnetic properties of Fe nanoislands on Cu(111)
International Nuclear Information System (INIS)
Kishi, Tomoya; David, Melanie; Nakanishi, Hiroshi; Kasai, Hideaki; Dino, Wilson Agerico; Komori, Fumio
2005-01-01
We investigate magnetic properties of Fe nanoislands on Cu(111) in the relaxed structure within the density functional theory. We observe that the nanoislands exhibit the ferromagnetic properties with large magnetic moment. We find that the change in the magnetic moment of each Fe atom is induced by deposition on Cu(111) and structure relaxation of Fe nanoislands. Moreover, we examine the stability of ferromagnetic states of Fe nanoislands by performing the total energy calculations. (author)
Ground state configurations in antiferromagnetic ultrathin films with dipolar anisotropy
International Nuclear Information System (INIS)
León, H.
2013-01-01
The formalism developed in a previous work to calculate the dipolar energy in quasi-two-dimensional crystals with ferromagnetic order is now extended to collinear antiferromagnetic order. Numerical calculations of the dipolar energy are carried out for systems with tetragonally distorted fcc [001] structures, the case of NiO and MnO ultrathin film grown in non-magnetic substrates, where the magnetic phase is a consequence of superexchange and dipolar interactions. The employed approximation allows to demonstrate that dipolar coupling between atomic layers is responsible for the orientation of the magnetization when it differs from the one in a single layer. The ground state energy of a given NiO or MnO film is found to depend not only on the strain, but also on how much the interlayer separation and the 2D lattice constant are changed with respect to the ideal values corresponding to the non-distorted cubic structure. Nevertheless, it is shown that the orientation of the magnetization in the magnetic phase of any of these films is determined by the strain exclusively. A striped phase with the magnetization along the [112 ¯ ] direction appears as the ground state configuration of NiO and MnO ultrathin films. In films with equally oriented stripes along the layers this magnetic phase is twofold degenerate, while in films with multidomain layers it is eightfold degenerate. These results are not in contradiction with experimentally observed out-of-plane or in-plane magnetization of striped phases in NiO and MnO ultrathin films. - Highlights: ► Dipolar energy in collinear antiferromagnetic ultrathin films is calculated. ► Numerical results are presented for distorted fcc [001] structures. ► The lowest energy of a system depends on how the tetragonal distortion is achieved. ► A striped phase with magnetization in the [112 ¯ ] direction is the ground state. ► In multidomain NiO and MnO films it is eightfold degenerate.
Effects of particle-number-projection on nuclear moment of intertia
International Nuclear Information System (INIS)
Rozmej, P.
1976-01-01
The formalism of the moment of inertia in cranking model and BCS theory has been extended for the partially particle-number-projected BCS wave functions. The ground state moments of inertia obtained by this method are a little greater than those calculated by BCS method. A smooth growth of the moments of inertia for diminishing pairing strength constant has been obtained. (author)
The Erez–Rosen metric and the role of the quadrupole on light propagation
International Nuclear Information System (INIS)
Bini, Donato; Crosta, Mariateresa; Vecchiato, Alberto; De Felice, Fernando; Geralico, Andrea
2013-01-01
The gravitational field of a static body with the quadrupole moment is described by an exact solution found by Erez and Rosen. Here, we investigate the role of the quadrupole in the motion, deflection and lensing of a light ray in the above metric. The standard lensing observables such as image positions and magnification have been explicitly obtained in the weak-field and small-quadrupole limit. In this limit, the spacetime metric appears as the natural generalization to quadrupole corrections of the metric form adopted also in current astrometric models. Hence, the corresponding analytical solution of the inverse ray tracing problem and the consistency with other approaches are also discussed. (paper)
ISR Superconducting Quadrupoles
1977-01-01
Michel Bouvier is preparing for curing the 6-pole superconducting windings inbedded in the cylindrical wall separating liquid helium from vacuum in the quadrupole aperture. The heat for curing the epoxy glue was provided by a ramp of infrared lamps which can be seen above the slowly rotating cylinder. See also 7703512X, 7702690X.
International Nuclear Information System (INIS)
Stokes, R.H.; Crandall, K.R.; Stovall, J.E.; Swenson, D.A.
1979-01-01
A method has been developed to analyze the beam dynamics of the radiofrequency quadrupole accelerating structure. Calculations show that this structure can accept a dc beam at low velocity, bunch it with high capture efficiency, and accelerate it to a velocity suitable for injection into a drift tube linac
1983-01-01
There were 48 of these Quadrupoles in the ISR. They were distributed around the rings according to the so-called Terwilliger scheme. Their aperture was 184 mm, their core length 300 mm, their gradient 5 T/m. Due to their small length as compared to the aperture, the end fringe field errors had to be compensated by suitably shaping the poles.
Energy of ground state of laminar electron-hole liquid
International Nuclear Information System (INIS)
Andryushin, E.A.
1976-01-01
The problem of a possible existence of metal electron-hole liquid in semiconductors is considered. The calculation has been carried out for the following model: two parallel planes are separated with the distance on one of the planes electrons moving, on the other holes doing. Transitions between the planes are forbidden. The density of particles for both planes is the same. The energy of the ground state and correlation functions for such electron-and hole system are calculated. It is shown that the state of a metal liquid is more advantageous against the exciton gas. For the mass ratio of electrons and holes, msub(e)/msub(h) → 0 a smooth rearrangement of the system into a state with ordered heavy particles is observed
Liquid 4He: Modified LOCV ground-state energy calculations
International Nuclear Information System (INIS)
Skjetne, B.; Ostgaard, E.
1996-01-01
The ground-state energetics of liquid 4 He is studied in a constrained variational approach, where the significance of neglecting terms beyond second order in the cluster expansion is estimated in a crude way. An adjustment to the conditions of healing on the two-body correlation function excludes from the global average field the effects of pairwise clustering to higher orders. To this end, open-quotes virtualclose quotes particles beyond nearest neighbors are included in the average correlation volume. Results within the scope of such modifications are consistent with GFMC and QDMC calculations, falling within the range -7.25 ± 0.05 K when recent interaction models are used
Electron scattering from the ground state of mercury
International Nuclear Information System (INIS)
Fursa, D.; Bray, I.
2000-01-01
Full text: Close-coupling calculations have been performed for electron scattering from the ground state of mercury. We have used non-relativistic convergent close-coupling computer code with only minor modifications in order to account for the most prominent relativistic effects. These are the relativistic shift effect and singlet-triplet mixing. Very good agreement with measurements of differential cross sections for elastic scattering and excitation of 6s6p 1 P state at all energies is obtained. It is well recognised that a consistent approach to electron scattering from heavy atoms (like mercury, with nuclear charge Z=80) must be based on a fully relativistic Dirac equations based technique. While development of such technique is under progress in our group, the complexity of the problem ensures that results will not be available in the near future. On other hand, there is considerable interest in reliable theoretical results for electron scattering from heavy atoms from both applications and the need to interpret existing experimental data. This is particularly the case for mercury, which is the major component in fluorescent lighting devices and has been the subject of intense experimental study since nineteen thirties. Similarly to our approach for alkaline-earth atoms we use a model of two valence electrons above an inert Hartree-Fock core to describe the mercury atom. Note that this model does not account for any core excited states which are present in the mercury discrete spectrum. The major effect of missing core-excited states is substantial underestimation of the static dipole polarizability of the mercury ground state (34 a.u.) and consequent underestimation of the forward scattering elastic cross sections. We correct for this by adding in the scattering calculations a phenomenological polarization potential. In order to obtain correct ground state ionization energy for mercury one has to account for the relativistic shift effect. We model this
Symmetry Breakdown in Ground State Dissociation of HD+
International Nuclear Information System (INIS)
Ben-Itzhak, I.; Wells, E.; Carnes, K. D.; Krishnamurthi, Vidhya; Weaver, O. L.; Esry, B. D.
2000-01-01
Experimental studies of the dissociation of the electronic ground state of HD + following ionization of HD by fast proton impact indicate that the H + +D 1s dissociation channel is more likely than the H1s+D + dissociation channel by about 7% . This isotopic symmetry breakdown is due to the finite nuclear mass correction to the Born-Oppenheimer approximation which makes the 1sσ state 3.7 meV lower than the 2pσ state at the dissociation limit. The measured fractions of the two dissociation channels are in agreement with coupled-channels calculations of 1sσ to 2pσ transitions. (c) 2000 The American Physical Society
Ground-state properties of neutron magic nuclei
Energy Technology Data Exchange (ETDEWEB)
Saxena, G., E-mail: gauravphy@gmail.com [Govt. Women Engineering College, Department of Physics (India); Kaushik, M. [Shankara Institute of Technology, Department of Physics (India)
2017-03-15
A systematic study of the ground-state properties of the entire chains of even–even neutron magic nuclei represented by isotones of traditional neutron magic numbers N = 8, 20, 40, 50, 82, and 126 has been carried out using relativistic mean-field plus Bardeen–Cooper–Schrieffer approach. Our present investigation includes deformation, binding energy, two-proton separation energy, single-particle energy, rms radii along with proton and neutron density profiles, etc. Several of these results are compared with the results calculated using nonrelativistic approach (Skyrme–Hartree–Fock method) along with available experimental data and indeed they are found with excellent agreement. In addition, the possible locations of the proton and neutron drip-lines, the (Z, N) values for the new shell closures, disappearance of traditional shell closures as suggested by the detailed analyzes of results are also discussed in detail.
Magnetic ground state of Ti{sub 1-x}Sc{sub x}Fe{sub 2} system
Energy Technology Data Exchange (ETDEWEB)
Saoudi, M.; Deportes, J.; Ouladdiaf, B. E-mail: ouladdiaf@ill.fr
2001-06-01
The magnetic ground states of the Laves phases Ti{sub 1-x}Sc{sub x}Fe{sub 2} system have been investigated by means of powder neutron diffraction and magnetisation techniques. For x=0.23, a transition is observed from a collinear ferromagnet along the c-axis to a canted one at T{sub f}=200 K. For x=0.27, 0.3, 0.33, an additional first-order transition is observed at T{sub t1}{approx}120 K accompanied by a large magnetovolume anomaly associated to a jump of the magnetic moment of the Fe atoms at the 2a site. The magnetic moment instability in a frustrated lattice should be considered to interpret this transition, although most of the other magnetic states can be discussed within Moriya's theory for itinerant electron systems with competing ferromagnetic and antiferromagnetic spin fluctuations.
Quadrupole Transfer Function for Emittance Measurement
Cameron, Peter; Jansson, Andreas; Tan, Cheng-Yang
2008-01-01
Historically the use of the quadrupole moment measurement has been impeded by the requirement for large dynamic range, as well as measurement sensitivity to beam position. We investigate the use of the transfer function technique [1-3] in combination with the sensitivity and 160dB revolution line rejection of the direct diode detection analog front end [4] to open the possibility of an emittance diagnostic that may be implemented without operational complication, quasi- parasitic to the operation of existing tune measurement systems. Such a diagnostic would be particularly useful as an emittance monitor during acceleration ramp development in machines like RHIC and the LHC.
Global set of quadrupole deformation parameters for even-even nuclei
International Nuclear Information System (INIS)
Raman, S.; Nestor, C.W. Jr.
1986-01-01
A compilation of experimental results has been completed for the reduced electric quadrupole transition probability [B(E2)up arrow] between the 0 + ground state and the first 2 + state in even-even nuclei. This compilation together with certain simple relationships noted by other authors can be used to make reasonable predictions of unmeasured B(E2)up arrow values. The quadrupole deformation parameter β 2 immediately follows, because β 2 is proportional to [B(E2)up arrow]/sup 1/2/. 8 refs., 7 figs
Quadrupole interactions in pionic and muonic tantalum and rhenium
International Nuclear Information System (INIS)
Konijn, J.; Doesburg, W. van; Ewan, G.T; Johansson, T.; Tibell, G.
1981-01-01
The hyperfine splitting of pionic and muonic X-rays in natural Re has been studied using the known ratio (accurate to 1.6 parts in 10 5 ) of the quadrupole moments of the two naturally occurring 185 Re and 187 Re isotopes. From the hyperfine splitting of the 5g → 4f and 4f → 3d pionic X-rays the effective quadrupole hyperfine constants were determined to be 187 A 2 sup(e)sup(f)sup(f) (4f) = 1.163 +- 0.010 keV and 187 A 2 sup(e)sup(f)sup(f) (3d) = 5.39 +- 0.63 keV, giving strong interaction quadrupole shifts epsilon 2 (4f) = 46 +- 10 eV and epsilon 2 (3d) = 1.3 +- 0.6 keV. The strong interaction monopole shifts epsilon 0 and widths GAMMA 0 of the 5g, 4f and 3d levels have also been measured. For the two higher orbits, standard optical-potential calculations fit the measured shifts and widths quite well. The observed deeper-lying 3d state, however, has shifts and widths that differ by a factor of 2 or more from the predictions. From the measured quadrupole hyperfine constants of the 4f level we calculate the spectroscopic quadrupole moments to be 187 Qsup(μ) = 2.09 +- 0.04 b, 187 Qsup(π) = 2.07 +- 0.02 b, 185 Qsup(μ) = 2.21 +- 0.04 b, and 185 Qsup(π) = 2.18 +- 0.02 b. In addition, muonic X-rays from 181 Ta were observed; using the same methods for determining the quadrupole moments as above, a value of 181 Qsup(μ) = 3.28 +- 0.06 b was obtained, in good agreement with earlier published data. (orig.)
Variable Permanent Magnet Quadrupole
International Nuclear Information System (INIS)
Mihara, T.; Iwashita, Y.; Kyoto U.; Kumada, M.; NIRS, Chiba; Spencer, C.M.; SLAC
2007-01-01
A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four parts and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments
Electric moments in molecule interferometry
International Nuclear Information System (INIS)
Eibenberger, Sandra; Gerlich, Stefan; Arndt, Markus; Tuexen, Jens; Mayor, Marcel
2011-01-01
We investigate the influence of different electric moments on the shift and dephasing of molecules in a matter wave interferometer. Firstly, we provide a quantitative comparison of two molecules that are non-polar yet polarizable in their thermal ground state and that differ in their stiffness and response to thermal excitations. While C 25 H 20 is rather rigid, its larger derivative C 49 H 16 F 52 is additionally equipped with floppy side chains and vibrationally activated dipole moment variations. Secondly, we elucidate the role of a permanent electric dipole momentby contrasting the quantum interference pattern of a (nearly) non-polar and a polar porphyrin derivative. We find that a high molecular polarizability and even sizeable dipole moment fluctuations are still well compatible with high-contrast quantum interference fringes. The presence of permanent electric dipole moments, however, can lead to a dephasing and rapid degradation of the quantum fringe pattern already at moderate electric fields. This finding is of high relevance for coherence experiments with large organic molecules, which are generally equipped with strong electric moments.
International Nuclear Information System (INIS)
Bush, E.D. Jr.
1976-01-01
A family of quadrupole magnets using a soft iron return yoke and circular cross-section permanent magnet poles were fabricated to investigate the feasibility for use in ion or electron beam focusing applications in accelerators and transport lines. Magnetic field measurements yielded promising results. In fixed-field applications, permanent magnets with sufficient gradients would be a low cost substitute for conventional electromagnets, eliminating the need for power supplies, associated wiring, and cooling. (author)
On quantum quadrupole radiation
International Nuclear Information System (INIS)
Fonda, L.; Mankoc-Borstnik, N.
1981-02-01
In this paper it is shown that for the electromagnetic decay of a quantum system in a coherent rotational state the total quadrupole radiation is proportional to (d 5 Q/dt 5 )(dQ/dt)sup(*)+c.c. For the radiation flux out of a sphere of large radius a different quantity, closer to the classical expression (d 3 Q/dt 3 ) 2 , is found. (author)
Superconducting Panofsky quadrupoles
International Nuclear Information System (INIS)
Harwood, L.H.
1981-01-01
A design for a rectangular aperture quadrupole magnet without pole-tips was introduced by Hand and Panofsky in 1959. This design was quite radical but simple to construct. Few magnets of this design were ever built because of the large power needed. With the advent of superconducting coils there has been a renewed interest in them. The mathematical basis, field characteristics, and present and future construction of these magnets are described
Measurements of quadrupole magnets
International Nuclear Information System (INIS)
Conradie, J.L.; Fourie, D.T.; Cornell, J.C.; Lloyd, G.C.W.
1987-01-01
Measurements carried out on quadrupole magnets using a long asymmetric rotating coil are described. Although the method itself is fairly well-known, the introduction of microprocessors has made this once-tedious technique into a useful and simple method of evaluating quadrupole magnets. The rotating-coil device and a variety of coil sizes are now commercially available. The coil contains a large number of extremely fine wires, embedded in a carefully balanced fibre-glass rotor, resulting in a reasonable induced voltage when the coil is rotated. A digital harmonic analyser is then used to obtain the integrated multipole content of the waveform, while the coil is rotating. By integrating over time, one can average out random noise and increase the reliability and repeatability of the measurements. Because the harmonic analysis is done in real time, the method is quick, easy and accurate, and has been extended to locate the precise magnetic centre of the quadrupole magnet by adjusting its position relative to the coil axis so as to minimize the dipole content of the output waveform. Results of these measurements are compared with those obtained with an optical method using a suspension of magnetite. The observed light pattern is explained analytically. (author)
Ground state analysis of magnetic nanographene molecules with modified edge
International Nuclear Information System (INIS)
Gorjizadeh, Narjes; Ota, Norio; Kawazoe, Yoshiyuki
2013-01-01
Highlights: ► Graphene molecules can become ferromagnetic by edge modifications. ► Dihydrogenation of one zigzag edge of rectangular flakes make them ferromagnetic. ► Triangular flakes become high-spin state by dehydrogenization of one zigzag edge. - Abstract: We study spin states of edge modified nanographene molecules with rectangular and triangular shapes by first principle calculations using density functional theory (DFT) and Hartree–Fock (HF) methods with Møller–Plesset (MP) correlation energy correction at different levels. Anthracene (C 14 H 10 ) and phenalenyl (C 13 H 9 ), which contain three benzene rings combined in two different ways, can be considered as fragments of a graphene sheet. Carbon-based ferromagnetic materials are of great interest both in fundamental science and technological potential in organic spintronics devices. We show that non-magnetic rectangular molecules such as C 14 H 10 can become ferromagnetic with high-spin state as the ground state by dihydrogenization of one of the zigzag edges, while triangular molecules such as C 13 H 9 become ferromagnetic with high-spin state by dehydrogenization of one of the zigzag edges
Hara, Akito; Awano, Teruyoshi
2017-06-01
Ultrashallow thermal donors (USTDs), which consist of light element impurities such as carbon, hydrogen, and oxygen, have been found in Czochralski silicon (CZ Si) crystals. To the best of our knowledge, these are the shallowest hydrogen-like donors with negative central-cell corrections in Si. We observed the ground-state splitting of USTDs by far-infrared optical absorption at different temperatures. The upper ground-state levels are approximately 4 meV higher than the ground-state levels. This energy level splitting is also consistent with that obtained by thermal excitation from the ground state to the upper ground state. This is direct evidence that the wave function of the USTD ground state is made up of a linear combination of conduction band minimums.
The first LHC insertion quadrupole
2004-01-01
An important milestone was reached in December 2003 at the CERN Magnet Assembly Facility. The team from the Accelerator Technology - Magnet and Electrical Systems group, AT-MEL, completed the first special superconducting quadrupole for the LHC insertions which house the experiments and major collider systems. The magnet is 8 metres long and contains two matching quadrupole magnets and an orbit corrector, a dipole magnet, used to correct errors in quadrupole alignment. All were tested in liquid helium and reached the ultimate performance criteria required for the LHC. After insertion in the cryostat, the superconducting magnet will be installed as the Q9 quadrupole in sector 7-8, the first sector of the LHC to be put in place in 2004. Members of the quadrupole team, from the AT-MEL group, gathered around the Q9 quadrupole at its inauguration on 12 December 2003 in building 181.
Quadrupole moments of low-lying baryons with spin
Indian Academy of Sciences (India)
2015-11-27
Proceedings of the International Workshop/Conference on Computational Condensed Matter Physics and Materials Science (IWCCMP-2015). Posted on November 27, 2015. Guest Editors: Anurag Srivastava, C. S. Praveen, H. S. Tewari. © 2015 Indian Academy of Sciences, Bengaluru. Contact | Site index.
Anomalous Ground State of the Electrons in Nano-confined Water
2016-06-13
Anomalous ground state of the electrons in nano -confined water G. F. Reiter1*, Aniruddha Deb2*, Y. Sakurai3, M. Itou3, V. G. Krishnan4, S. J...electronic ground state of nano -confined water must be responsible for these anomalies but has so far not been investigated. We show here for the first time...using x-ray Compton scattering and a computational model, that the ground state configuration of the valence electrons in a particular nano
Ion trajectories quadrupole mass filters
International Nuclear Information System (INIS)
Ursu, D.; Lupsa, N.; Muntean, F.
1994-01-01
The present paper aims at bringing some contributions to the understanding of ion motion in quadrupole mass filters. The theoretical treatment of quadrupole mass filter is intended to be a concise derivation of the important physical relationships using Mathieu functions. A simple iterative method of numerical computation has been used to simulate ion trajectories in an ideal quadrupole field. Finally, some examples of calculation are presented with the aid of computer graphics. (Author) 14 Figs., 1 Tab., 20 Refs
MQXFS1 Quadrupole Design Report
Energy Technology Data Exchange (ETDEWEB)
Ambrosio, Giorgio [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); et al.
2016-04-14
This report presents the reference design of MQXFS1, the first 1.5 m prototype of the low-beta quadrupoles (MQXF) for the LHC High Luminosity Upgrade. The MQXF quadrupoles have 150 mm aperture, coil peak field of about 12 T, and use $Nb_{3}Sn$ conductor. The design is based on the LARP HQ quadrupoles, which had 120 mm aperture. MQXFS1 has 1st generation cable cross-section and magnetic design.
Ground state solutions for asymptotically periodic Schrodinger equations with critical growth
Directory of Open Access Journals (Sweden)
Hui Zhang
2013-10-01
Full Text Available Using the Nehari manifold and the concentration compactness principle, we study the existence of ground state solutions for asymptotically periodic Schrodinger equations with critical growth.
Correlated ground state and E2 giant resonance built on it
International Nuclear Information System (INIS)
Tohyama, Mitsuru
1995-01-01
Taking 16 O as an example of realistic nuclei, we demonstrate that a correlated ground state can be obtained as a long time solution of a time-dependent density-matrix formalism (TDDM) when the residual interaction is adiabatically treated. We also study in TDDM the E2 giant resonance of 16 O built on the correlated ground state and compare it with that built on the Hartree-Fock ground state. It is found that a spurious mixing of low frequency components seen in the latter is eliminated by using the correlated ground state. (author)
Czech Academy of Sciences Publication Activity Database
Arnold, Zdeněk; Kuchin, A.; Kamarád, Jiří
2012-01-01
Roč. 111, č. 7 (2012), "07E310-1"-"07E310-3" ISSN 0021-8979 R&D Projects: GA ČR GA202/09/1027 Institutional research plan: CEZ:AV0Z10100521 Keywords : ferromagnetic ground state, Magnetic moments * magnetic moments Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.210, year: 2012
Shell model calculation of the nuclear moments of 9Li in a 2hω space
International Nuclear Information System (INIS)
Chang, Y.; Meder, M.R.
1984-01-01
A recent measurement of the magnitude of quadrupole moment of the ground state of 9 Li, Q( 9 Li), finds that Vertical BarQ( 9 Li)/Q( 7 Li)Vertical Bar = 0.88 +- 0.18. A variety of shell-model calculations, using p-shell wave functions, predict Q( 9 Li)approx. =1.3Q( 7 Li) and yield quadrupole moments whose magnitudes are approximately half the experimental values. Agreement between theory and experiment is improved when effective charges are used, although the results are still not completely satisfactory. A calculation of the wave functions of the low-lying states of 7 Li and 9 Li using a modified version of the Sussex matrix elements in a model space, including all 0hω and 2hω excitations, has been performed. The resulting value for Q( 9 Li) was -3.46 fm 2 as ray transitions in /sup 52,53/Cr and /sup 54,55/Mn have been observed using 7 Li( 51 V,xn yp zα γ) fusion-evaporation reactions and γ-particle coincidence techniques. The experiment involved the same reaction at the same center-of-mass energy as the earlier work of Poletti et al., but with target and projectile interchanged. In the present work, eight additional transitions have been identified as occurring in 52 Cr. This provides corroboration of results obtained more recently via 50 Ti(α,2nγ) 52 Cr reaction studies. A simple, efficient approach to the spectroscopy of weakly populated nuclear states which provides for unambiguous isotopic assignments is thus demonstrated
Magnetic ground states in nanocuboids of cubic magnetocrystalline anisotropy
Energy Technology Data Exchange (ETDEWEB)
Bonilla, F.J., E-mail: fbonilla@cicenergigune.com; Lacroix, L.-M.; Blon, T., E-mail: thomas.blon@insa-toulouse.fr
2017-04-15
Flower and easy-axis vortex states are well-known magnetic configurations that can be stabilized in small particles. However, <111> vortex (V<111>), i.e. a vortex state with its core axis along the hard-axis direction, has been recently evidenced as a stable configuration in Fe nanocubes of intermediate sizes in the flower/vortex transition. In this context, we present here extensive micromagnetic simulations to determine the different magnetic ground states in ferromagnetic nanocuboids exhibiting cubic magnetocrystalline anisotropy (MCA). Focusing our study in the single-domain/multidomain size range (10–50 nm), we showed that V<111> is only stable in nanocuboids exhibiting peculiar features, such as a specific size, shape and magnetic environment, contrarily to the classical flower and easy-axis vortex states. Thus, to track experimentally these V<111> states, one should focused on (i) nanocuboids exhibiting a nearly perfect cubic shape (size distorsion <12%) made of (ii) a material which combines a zero or positive MCA and a high saturation magnetization, such as Fe or FeCo; and (iii) a low magnetic field environment, V<111> being only observed in virgin or remanent states. - Highlights: • The <111> vortex is numerically determined in nanocubes of cubic anisotropy. • It constitutes an intermediate state in the single-domain limit. • Such a vortex can only be stabilized in perfect or slightly deformed nanocuboids. • It exists in nanocuboids made of materials with zero or positive cubic anisotropy. • The associated magnetization reversal is described by a rotation of the vortex axis.
Mathematical aspects of ground state tunneling models in luminescence materials
International Nuclear Information System (INIS)
Pagonis, Vasilis; Kitis, George
2015-01-01
Luminescence signals from a variety of natural materials have been known to decrease with storage time at room temperature due to quantum tunneling, a phenomenon known as anomalous fading. This paper is a study of several mathematical aspects of two previously published luminescence models which describe tunneling phenomena from the ground state of a donor–acceptor system. It is shown that both models are described by the same type of integral equation, and two new analytical equations are presented. The first new analytical equation describes the effect of anomalous fading on the dose response curves (DRCs) of naturally irradiated samples. The DRCs in the model were previously expressed in the form of integral equations requiring numerical integration, while the new analytical equation can be used immediately as a tool for analyzing experimental data. The second analytical equation presented in this paper describes the anomalous fading rate (g-Value per decade) as a function of the charge density in the model. This new analytical expression for the g-Value is tested using experimental anomalous fading data for several apatite crystals which exhibit high rate of anomalous fading. The two new analytical results can be useful tools for analyzing anomalous fading data from luminescence materials. In addition to the two new analytical equations, an explanation is provided for the numerical value of a constant previously introduced in the models. - Highlights: • Comparative study of two luminescence models for feldspars. • Two new analytical equations for dose response curves and anomalous fading rate. • The numerical value z=1.8 of previously introduced constant in models explained.
Moment methods and Lanczos methods
International Nuclear Information System (INIS)
Whitehead, R.R.
1980-01-01
In contrast to many of the speakers at this conference I am less interested in average properties of nuclei than in detailed spectroscopy. I will try to show, however, that the two are very closely connected and that shell-model calculations may be used to give a great deal of information not normally associated with the shell-model. It has been demonstrated clearly to us that the level spacing fluctuations in nuclear spectra convey very little physical information. This is true when the fluctuations are averaged over the entire spectrum but not if one's interest is in the lowest few states, whose spacings are relatively large. If one wishes to calculate a ground state (say) accurately, that is with an error much smaller than the excitation energy of the first excited state, very high moments, μ/sub n/, n approx. 200, are needed. As I shall show, we use such moments as a matter of course, albeit without actually calculating them; in fact I will try to show that, if at all possible, the actual calculations of moments is to be avoided like the plague. At the heart of the new shell-model methods embodied in the Glasgow shell-model program and one or two similar ones is the so-called Lanczos method and this, it turns out, has many deep and subtle connections with the mathematical theory of moments. It is these connections that I will explore here
High-field magnetoconductance in La-Sr manganites of FM and AFM ground states
Jirák, Zdeněk; Kaman, Ondřej; Knížek, Karel; Levinský, Petr; Míšek, Martin; Veverka, Pavel; Hejtmánek, Jiří
2018-06-01
Large-grain La1-xSrxMnO3 ceramic samples of compositions x = 0.45 and 0.55, representing the ferromagnetic (FM) and A-type antiferromagnetic (AFM) ground states, were produced via classical sintering at 1500 °C of cold-pressed sol-gel prepared single-phase nanoparticles. Using the same precursors, nanogranular forms of both manganite ceramics were prepared by fast spark plasma sintering at low temperature of 900 °C, which limits the growth of crystal grains. The magnetotransport of both the bulk and nanogranular forms was investigated in a broad range of magnetic fields up to 130 kOe and analyzed on the basis of detailed magnetic measurements. Both the large-grain and nanogranular systems with x = 0.45, possessing a pure FM state with similar Curie tempereature TC ≈ 345 K), show nearly the same conductivity enhancement in external fields when expressed relatively to the zero-field values. This positive magnetoconductance (MC) can be separated into two terms: (i) the hysteretic low-field MC that reflects the field-induced orientation of magnetic moments of individual grains, and (ii) the high-field MC that depends linearly on external field. In the case of large-grain ceramics with x = 0.55, a partially ordered FM state formed below TC = 264 K is replaced by pure A-type AFM ground state below 204 K. This A-type AFM state is characterized by positive magnetoconductance that is essentially of quadratic dependence on external field in the investigated range up to 130 kOe. On contrary, the nanogranular product with x = 0.55 exhibits a mixed FM/AFM state at low temperatures, and, as a consequence, its magnetotransport combines the features of FM and A-type AFM systems, in which the quadratic term is much enhanced and clearly dominates at high fields. For interpretation of observed behaviors, the theory of grain-boundary tunneling is revisited.
Study of Nuclear Moments and Mean Square Charge Radii by Collinear Fast-Beam Laser Spectroscopy
2002-01-01
The collinear fast-beam laser technique is used to measure atomic hyperfine structures and isotope shifts of unstable nuclides produced at ISOLDE. This gives access to basic nuclear ground-state and isomeric-state properties such as spins, magnetic dipole and electric quadrupole moments, and the variation of the nuclear mean square charge radius within a sequence of isotopes. \\\\ \\\\ Among the various techniques used for this purpose, the present approach is of greatest versatility, due to the direct use of the beams from the isotope separator. Their phase-space properties are exploited to achieve high sensitivity and resolution. The optical spectra of neutral atoms are made accessible by converting the ion beams into fast atomic beams. This is accomplished in the charge-exchange cell which is kept at variable potential ($\\pm$10~kV) for Doppler-tuning of the effective laser wavelength. The basic optical resolution of 10$^{-8}$ requires a 10$^{-5}$ stability of the 60~kV main acceleration voltage and low energy ...
Tricriticality for dimeric Coulomb molecular crystals in ground state
Travěnec, Igor; Šamaj, Ladislav
2017-12-01
We study the ground-state properties of a system of dimers. Each dimer consists in a pair of equivalent charges at a fixed distance, immersed in a neutralizing homogeneous background. All charges interact pairwisely by Coulomb potential. The dimer centers form a two-dimensional rectangular lattice with the aspect ratio α\\in [0, 1] and each dimer is allowed to rotate around its center. The previous numerical simulations, made for the more general Yukawa interaction, indicate that only two basic dimer configurations can appear: either all dimers are parallel or they have two different angle orientations within alternating (checkerboard) sublattices. As the dimer size increases, two second-order phase transitions, related to two kinds of the symmetry breaking in dimer’s orientations, were reported. In this paper, we use a recent analytic method based on an expansion of the interaction energy in Misra functions which converges quickly and provides an analytic derivation of the critical behaviour. Our main result is that there exists a specific aspect ratio of the rectangular lattice α^*=0.714 106 840 000 71\\ldots which divides the space of model’s phases onto two distinct regions. If the lattice aspect ratio α>α* , we recover both types of the second-order phase transitions and find that they are of mean-field type with the critical exponent β = 1/2 . If 0.711 535≤slantα<α* , the phase transition associated with the discontinuity of dimer’s angles on alternating sublattices becomes of first order. For α=α* , the first- and second-order phase transitions meet at the tricritical point, characterized by the different critical index β = 1/4 . Such phenomenon is known from literature about the Landau theory of one-component fields, but in our two-component version the scenario is more complicated: the component which is already in the symmetry-broken state at the tricritical point also interferes and exhibits unexpectedly the mean-field singular
Derivation of novel human ground state naive pluripotent stem cells.
Gafni, Ohad; Weinberger, Leehee; Mansour, Abed AlFatah; Manor, Yair S; Chomsky, Elad; Ben-Yosef, Dalit; Kalma, Yael; Viukov, Sergey; Maza, Itay; Zviran, Asaf; Rais, Yoach; Shipony, Zohar; Mukamel, Zohar; Krupalnik, Vladislav; Zerbib, Mirie; Geula, Shay; Caspi, Inbal; Schneir, Dan; Shwartz, Tamar; Gilad, Shlomit; Amann-Zalcenstein, Daniela; Benjamin, Sima; Amit, Ido; Tanay, Amos; Massarwa, Rada; Novershtern, Noa; Hanna, Jacob H
2013-12-12
Mouse embryonic stem (ES) cells are isolated from the inner cell mass of blastocysts, and can be preserved in vitro in a naive inner-cell-mass-like configuration by providing exogenous stimulation with leukaemia inhibitory factor (LIF) and small molecule inhibition of ERK1/ERK2 and GSK3β signalling (termed 2i/LIF conditions). Hallmarks of naive pluripotency include driving Oct4 (also known as Pou5f1) transcription by its distal enhancer, retaining a pre-inactivation X chromosome state, and global reduction in DNA methylation and in H3K27me3 repressive chromatin mark deposition on developmental regulatory gene promoters. Upon withdrawal of 2i/LIF, naive mouse ES cells can drift towards a primed pluripotent state resembling that of the post-implantation epiblast. Although human ES cells share several molecular features with naive mouse ES cells, they also share a variety of epigenetic properties with primed murine epiblast stem cells (EpiSCs). These include predominant use of the proximal enhancer element to maintain OCT4 expression, pronounced tendency for X chromosome inactivation in most female human ES cells, increase in DNA methylation and prominent deposition of H3K27me3 and bivalent domain acquisition on lineage regulatory genes. The feasibility of establishing human ground state naive pluripotency in vitro with equivalent molecular and functional features to those characterized in mouse ES cells remains to be defined. Here we establish defined conditions that facilitate the derivation of genetically unmodified human naive pluripotent stem cells from already established primed human ES cells, from somatic cells through induced pluripotent stem (iPS) cell reprogramming or directly from blastocysts. The novel naive pluripotent cells validated herein retain molecular characteristics and functional properties that are highly similar to mouse naive ES cells, and distinct from conventional primed human pluripotent cells. This includes competence in the generation
Construction and study of exact ground states for a class of quantum antiferromagnets
International Nuclear Information System (INIS)
Fannes, M.
1989-01-01
Techniques of quantum probability are used to construct the exact ground states for a class of quantum spin systems in one dimension. This class in particular contains the antiferromagnetic models introduced by various authors under the name of VBS-models. The construction permits a detailed study of these ground states. (A.C.A.S.) [pt
Ground state of charged Base and Fermi fluids in strong coupling
International Nuclear Information System (INIS)
Mazighi, R.
1982-03-01
The ground state and excited states of the charged Bose gas were studied (wave function, equation of state, thermodynamics, application of Feynman theory). The ground state of the charged Fermi gas was also investigated together with the miscibility of charged Bose and Fermi gases at 0 deg K (bosons-bosons, fermions-bosons and fermions-fermions) [fr
Long range order in the ground state of two-dimensional antiferromagnets
International Nuclear Information System (INIS)
Neves, E.J.; Perez, J.F.
1985-01-01
The existence of long range order is shown in the ground state of the two-dimensional isotropic Heisenberg antiferromagnet for S >= 3/2. The method yields also long range order for the ground state of a larger class of anisotropic quantum antiferromagnetic spin systems with or without transverse magnetic fields. (Author) [pt
Ab initio calculation atomics ground state wave function for interactions Ion- Atom
International Nuclear Information System (INIS)
Shojaee, F.; Bolori zadeh, M. A.
2007-01-01
Ab initio calculation atomics ground state wave function for interactions Ion- Atom Atomic wave function expressed in a Slater - type basis obtained within Roothaan- Hartree - Fock for the ground state of the atoms He through B. The total energy is given for each atom.
Ground State Structure of a Coupled 2-Fermion System in Supersymmetric Quantum Mechanics
Finster, Felix
1997-05-01
We prove the uniqueness of the ground state for a supersymmetric quantum mechanical system of two fermions and two bosons, which is closely related to theN=1 WZ-model. The proof is constructive and gives detailed information on what the ground state looks like
Ground state structure of a coupled 2-fermion system in supersymmetric quantum mechanics
International Nuclear Information System (INIS)
Finster, F.
1997-01-01
We prove the uniqueness of the ground state for a supersymmetric quantum mechanical system of two fermions and two bosons, which is closely related to the N=1 WZ-model. The proof is constructive and gives detailed information on what the ground state looks like. copyright 1997 Academic Press, Inc
Quadrupole shunt experiments at SPEAR
International Nuclear Information System (INIS)
Corbett, W.J.; Hettel, R.O.; Nuhn, H.-D.
1996-05-01
As part of a program to align and stabilize the SPEAR storage ring, a switchable shunt resistor was installed on each quadrupole to bypass a small percentage of the magnet current. The impact of a quadrupole shunt is to move the electron beam orbit in proportion to the off-axis beam position at the quadrupole, and to shift the betatron tune. Initially, quadrupole shunts in SPEAR were used to position the electron beam in the center of the quadrupoles. This provided readback offsets for nearby beam position monitors, and helped to steer the photon beams with low-amplitude corrector currents. The shunt-induced tune shift measurements were then processed in MAD to derive a lattice model
Quadrupole shunt experiments at SPEAR
International Nuclear Information System (INIS)
Corbett, W.J.; Hettel, R.O.; Nuhn, H.
1997-01-01
As part of a program to align and stabilize the SPEAR storage ring, a switchable shunt resistor was installed on each quadrupole to bypass a small percentage of the magnet current. The impact of a quadrupole shunt is to move the electron beam orbit in proportion to the off-axis beam position at the quadrupole and to shift the betatron tune. Initially, quadrupole shunts in SPEAR were used to position the electron beam in the center of the quadrupoles. This provided readback offsets for nearby beam position monitors and helped to steer the photon beams with low-amplitude corrector currents. The shunt-induced tune shift measurements were then processed in MAD to derive a lattice model. copyright 1997 American Institute of Physics
CLIC Quadrupole Module final report
Artoos, K; Mainaud-Durand, H
2013-01-01
Future Linear colliders will need particle beam sizes in the nanometre range. The beam also needs to be stable all along the beam line. The CLIC Main Beam Quadrupole (MBQ) module has been defined and studied. It is meant as a test stand for stabilisation and pre-alignment with a MB Quadrupole. The main topic that has been tackled concerns the Quadrupole magnet stabilisation to 1nm at 1Hz. This is needed to obtain the desired CLIC luminosity of 2.1034 cm-2m-1. The deliverable was demonstrated by procuring a MBQ and by stabilising a powered and cooled CLIC MBQ quadrupole. In addition, the stabilisation system has to be compatible with the pre-alignment procedures. Pre-alignment movement resolution has been demonstrated to 1m. The last step is the combined test of stability with a quadrupole on a CLIC Module with the pre-alignment.
Emittance growth from rotated quadrupoles in heavy ion accelerators
International Nuclear Information System (INIS)
Barnard, J.J.
1995-01-01
We derive a set of moment equations which incorporates linear quadrupolar focusing and space-charge defocusing, in the presence of rotational misalignments of the quadrupoles about the direction of beam propagation. Although the usual beam emittance measured relative to fixed transverse x and y coordinate axes is not constant, a conserved emittance-like quantity has been found. Implications for alignment tolerances in accelerators for heavy-ion inertial fusion are discussed
Ground-state magnetization of the molecular cluster Mn12O12-acetate as seen by proton NMR
International Nuclear Information System (INIS)
Furukawa, Y.; Watanabe, K.; Kumagai, K.; Jang, Z. H.; Lascialfari, A.; Borsa, F.; Gatteschi, D.
2000-01-01
1 H nuclear magnetic resonance (NMR) measurements have been carried out in Mn 12 O 12 -acetate clusters at low temperature in order to investigate microscopically the static and dynamic magnetic properties of the molecule in its high-spin S=10 ground state. Below liquid helium temperature it is found that the local hyperfine fields at the proton sites are static as expected for the very slow superparamagnetic relaxation of Mn 12 O 12 at low temperature. The magnitude and distribution of the hyperfine fields can be reproduced to a good approximation by considering only the dipolar interaction of protons with the local Mn magnetic moments and by assigning the magnitude and orientation of the local moments of the different Mn 3+ and Mn 4+ ions according to an accepted coupling scheme for the total S=10 ground state. The relaxation time of the macroscopic magnetization of the cluster was measured by monitoring the change of the intensity of the 1 H-NMR shifted lines following inversion of the applied magnetic field. This is possible because the sudden change of the field orientation changes the sign of the shift of the NMR lines in the proton spectrum. Although important differences are noticed, the relaxation time of the magnetization as measured indirectly by the 1 H-NMR method is comparable to the one obtained directly with a superconducting quantum interference device magnetometer. In particular we could reproduce the minima in the relaxation time as a function of magnetic field at the fields for level crossing, minima which are considered to be a signature of the quantum tunneling of the magnetization
Appel, Markus; Frick, Bernhard; Elbert, Johannes; Gallei, Markus; Stühn, Bernd
2015-01-01
The quantum mechanical splitting of states by interaction of a magnetic moment with an external magnetic field is well known, e.g., as Zeeman effect in optical transitions, and is also often seen in magnetic neutron scattering. We report excitations observed in inelastic neutron spectroscopy on the redox-responsive polymer poly(vinylferrocene). They are interpreted as splitting of the electronic ground state in the organometallic ferrocene units attached to the polymer chain where a magnetic moment is created by oxidation. In a second experiment using high resolution neutron backscattering spectroscopy we observe the hyperfine splitting, i.e., interaction of nuclear magnetic moments with external magnetic fields leading to sub-μeV excitations observable in incoherent neutron spin-flip scattering on hydrogen and vanadium nuclei.
Skocek, Oliver; Uiberacker, Christoph; Jakubetz, Werner
2011-06-30
A computational investigation of HCN → HNC isomerization in the electronic ground state by one- and few-cycle infrared pulses is presented. Starting from a vibrationally pre-excited reagent state, isomerization yields of more than 50% are obtained using single one- to five-cycle pulses. The principal mechanism includes two steps of population transfer by dipole-resonance (DR), and hence, the success of the method is closely linked to the polarity of the system and, in particular, the stepwise change of the dipole moment from reactant to transition state and on to products. The yield drops massively if the diagonal dipole matrix elements are artificially set to zero. In detail, the mechanism includes DR-induced preparation of a delocalized vibrational wavepacket, which traverses the barrier region and is finally trapped in the product well by DR-dominated de-excitation. The excitation and de-excitation steps are triggered by pulse lobes of opposite field direction. As the number of optical cycles is increased, the leading field lobes prepare a vibrational superposition state by off-resonant ladder climbing, which is then subjected to the three steps of the principal isomerization mechanism. DR excitation is more efficient from a preformed vibrational wavepacket than from a molecular eigenstate. The entire process can be loosely described as Tannor-Kosloff-Rice type transfer mechanism on a single potential surface effected by a single pulse, individual field lobes assuming the roles of pump- and dump-pulses. Pre-excitation to a transient wavepacket can be enhanced by applying a separate, comparatively weak few-cycle prepulse, in which the prepulse prepares a vibrational wavepacket. The two-pulse setup corresponds to a double Tannor-Kosloff-Rice control scheme on a single potential surface.
The significant role of covalency in determining the ground state of cobalt phthalocyanines molecule
Directory of Open Access Journals (Sweden)
Jing Zhou
2016-03-01
Full Text Available To shed some light on the metal 3d ground state configuration of cobalt phthalocyanines system, so far in debate, we present an investigation by X-ray absorption spectroscopy (XAS at Co L2,3 edge and theoretical calculation. The density functional theory calculations reveal highly anisotropic covalent bond between central cobalt ion and nitrogen ligands, with the dominant σ donor accompanied by weak π-back acceptor interaction. Our combined experimental and theoretical study on the Co-L2,3 XAS spectra demonstrate a robust ground state of 2A1g symmetry that is built from 73% 3d7 character and 27% 3 d 8 L ¯ ( L ¯ denotes a ligand hole components, as the first excited-state with 2Eg symmetry lies about 158 meV higher in energy. The effect of anisotropic and isotropic covalency on the ground state was also calculated and the results indicate that the ground state with 2A1g symmetry is robust in a large range of anisotropic covalent strength while a transition of ground state from 2A1g to 2Eg configuration when isotropic covalent strength increases to a certain extent. Here, we address a significant anisotropic covalent effect of short Co(II-N bond on the ground state and suggest that it should be taken into account in determining the ground state of analogous cobalt complexes.
Exact many-electron ground states on diamond and triangle Hubbard chains
International Nuclear Information System (INIS)
Gulacsi, Zsolt; Kampf, Arno; Vollhardt, Dieter
2009-01-01
We construct exact ground states of interacting electrons on triangle and diamond Hubbard chains. The construction requires (1) a rewriting of the Hamiltonian into positive semidefinite form, (2) the construction of a many-electron ground state of this Hamiltonian, and (3) the proof of the uniqueness of the ground state. This approach works in any dimension, requires no integrability of the model, and only demands sufficiently many microscopic parameters in the Hamiltonian which have to fulfill certain relations. The scheme is first employed to construct exact ground state for the diamond Hubbard chain in a magnetic field. These ground states are found to exhibit a wide range of properties such as flat-band ferromagnetism and correlation induced metallic, half-metallic or insulating behavior, which can be tuned by changing the magnetic flux, local potentials, or electron density. Detailed proofs of the uniqueness of the ground states are presented. By the same technique exact ground states are constructed for triangle Hubbard chains and a one-dimensional periodic Anderson model with nearest-neighbor hybridization. They permit direct comparison with results obtained by variational techniques for f-electron ferromagnetism due to a flat band in CeRh 3 B 2 . (author)
International Nuclear Information System (INIS)
Beyer, Thomas
2014-01-01
The dominant fraction of elements heavier than iron was created in stellar nucleosynthesis by neutron-capture reactions. The isotopic compositions of these elements are the fingerprints of the involved processes, and a huge amount of experimental data on these isotopes is required to support corresponding astrophysical calculations and models. The TRIGA-SPEC experiment aims to contribute to these data by the measurement of ground-state properties of neutron-rich heavy nuclides. It consists of the Penning-trap mass spectrometer TRIGA-TRAP for the determination of masses, Q-values and binding energies, and the collinear laser spectroscopy setup TRIGALASER for the determination of charge radii, nuclear spins, and moments. The nuclides of interest are produced by neutron-induced fission of an actinide target inside the research reactor TRIGA Mainz and ionized in an online ion source. In the context of this thesis, the two experiments were coupled to the reactor, completing the ion beam preparation transfer line. This included the implementation and commissioning of a radio-frequency quadrupole for the emittance reduction and accumulation of the ions. The functionality of the ion beam preparation was verified by successful test measurements of stable nuclides produced in the online ion source.
International Nuclear Information System (INIS)
Piskunov, V.A.
1981-01-01
The following connection of windings of electromagnet is suggested for simplification of the design of qUadrupole magnetic lens intended for use in radiotechnical and electron-optical devices. The mentioned windings are connected with each other by a bridge scheme and the variable resistors are switched in its diagonals in the lens containing four electromagnet with windings connected with two variable resistors the mobile contacts of which are connected with a direct current source. Current redistribution between left windings and right windings takes place at shift of mobile contact of variable resistor, and current redistribution between upper and low coils of electromagnets takes place at shifting mobile contact of the other variable resistor. In this case smooth and independent electron-optical misalignment of lens by two mutually perpendicular directions proceeds. Use of the given design of the lens in the oscillograph permits to use printing assembly for alignment plate and to reduce the number of connections at the expense of decreasing the number of resistors
Dipole and electric quadrupole excitations in 40,48Ca
International Nuclear Information System (INIS)
Hartmann, T.; Enders, J.; Mohr, P.; Vogt, K.; Volz, S.; Zilges, A.
2001-11-01
Photon scattering experiments have been performed to investigate the structure of the two doubly magic nuclei 40,48 Ca. The method is highly selective to induce low-order multipole transitions i.e., E1, M1, and E2 from the ground state. We determined the energies and spins of excited states and the absolute strengths of the γ-decays in a model independent way. We find the summed electric dipole strengths below 10 MeV to exhaust the energy weighted sum rule (EWSR) by 0.023% and 0.27%, respectively. The summed electric quadrupole strengths are Σ B(E2) ↑ = 332 e 2 fm 4 and 407 e 2 fm 4 for 40 Ca and 48 Ca, respectively. In order to explain the difference in the E1 strengths of the two isotopes several theoretical models are discussed. (orig.)
Quantum tunneling of the magnetic moment in a free nanoparticle
International Nuclear Information System (INIS)
O'Keeffe, M.F.; Chudnovsky, E.M.; Garanin, D.A.
2012-01-01
We study tunneling of the magnetic moment in a particle that has full rotational freedom. Exact energy levels are obtained and the ground-state magnetic moment is computed for a symmetric rotor. The effect of mechanical freedom on spin tunneling manifests itself in a strong dependence of the magnetic moment on the moments of inertia of the rotor. The energy of the particle exhibits quantum phase transitions between states with different values of the magnetic moment. Particles of various shapes are investigated and the quantum phase diagram is obtained. - Highlights: ► We obtain an exact analytical solution of a tunneling spin in a mechanical rotator. ► The quantum phase diagram shows magnetic moment dependence on rotator shape and size. ► Our work explains magnetic properties of free atomic clusters and magnetic molecules.
Quantum tunneling of the magnetic moment in a free nanoparticle
Energy Technology Data Exchange (ETDEWEB)
O' Keeffe, M.F. [Physics Department, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, New York, 10468-1589 (United States); Chudnovsky, E.M., E-mail: eugene.chudnovsky@lehman.cuny.edu [Physics Department, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, New York, 10468-1589 (United States); Garanin, D.A. [Physics Department, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, New York, 10468-1589 (United States)
2012-09-15
We study tunneling of the magnetic moment in a particle that has full rotational freedom. Exact energy levels are obtained and the ground-state magnetic moment is computed for a symmetric rotor. The effect of mechanical freedom on spin tunneling manifests itself in a strong dependence of the magnetic moment on the moments of inertia of the rotor. The energy of the particle exhibits quantum phase transitions between states with different values of the magnetic moment. Particles of various shapes are investigated and the quantum phase diagram is obtained. - Highlights: Black-Right-Pointing-Pointer We obtain an exact analytical solution of a tunneling spin in a mechanical rotator. Black-Right-Pointing-Pointer The quantum phase diagram shows magnetic moment dependence on rotator shape and size. Black-Right-Pointing-Pointer Our work explains magnetic properties of free atomic clusters and magnetic molecules.
Nonspherical atomic ground-state densities and chemical deformation densities from x-ray scattering
International Nuclear Information System (INIS)
Ruedenberg, K.; Schwarz, W.H.E.
1990-01-01
Presuming that chemical insight can be gained from the difference between the molecular electron density and the superposition of the ground-state densities of the atoms in a molecule, it is pointed out that, for atoms with degenerate ground states, an unpromoted ''atom in a molecule'' is represented by a specific ensemble of the degenerate atomic ground-state wave functions and that this ensemble is determined by the anisotropic local surroundings. The resulting atomic density contributions are termed oriented ground state densities, and the corresponding density difference is called the chemical deformation density. The constraints implied by this conceptual approach for the atomic density contributions are formulated and a method is developed for determining them from x-ray scattering data. The electron density of the appropriate promolecule and its x-ray scattering are derived, the determination of the parameters of the promolecule is outlined, and the chemical deformation density is formulated
Pade approximants for the ground-state energy of closed-shell quantum dots
International Nuclear Information System (INIS)
Gonzalez, A.; Partoens, B.; Peeters, F.M.
1997-08-01
Analytic approximations to the ground-state energy of closed-shell quantum dots (number of electrons from 2 to 210) are presented in the form of two-point Pade approximants. These Pade approximants are constructed from the small- and large-density limits of the energy. We estimated that the maximum error, reached for intermediate densities, is less than ≤ 3%. Within that present approximation the ground-state is found to be unpolarized. (author). 21 refs, 3 figs, 2 tabs
A simple parameter-free wavefunction for the ground state of two-electron atoms
International Nuclear Information System (INIS)
Ancarani, L U; Rodriguez, K V; Gasaneo, G
2007-01-01
We propose a simple and pedagogical wavefunction for the ground state of two-electron atoms which (i) is parameter free (ii) satisfies all two-particle cusp conditions (iii) yields reasonable ground-state energies, including the prediction of a bound state for H - . The mean energy, and other mean physical quantities, is evaluated analytically. The simplicity of the result can be useful as an easy-to-use wavefunction when testing collision models
Many electron variational ground state of the two dimensional Anderson lattice
International Nuclear Information System (INIS)
Zhou, Y.; Bowen, S.P.; Mancini, J.D.
1991-02-01
A variational upper bound of the ground state energy of two dimensional finite Anderson lattices is determined as a function of lattice size (up to 16 x 16). Two different sets of many-electron basis vectors are used to determine the ground state for all values of the coulomb integral U. This variational scheme has been successfully tested for one dimensional models and should give good estimates in two dimensions
Ground-state energy for 1D (t,U,X)-model at low densities
International Nuclear Information System (INIS)
Buzatu, F.D.
1992-09-01
In describing the properties of quasi-1D materials with a highly-screened interelectronic potential, an attractive hopping term has to be added to the Hubbard Hamiltonian. The effective interaction and the ground-state energy in ladder approximation are analyzed. At low electronic densities, the attractive part of the interaction, initially smaller than the repulsive term, can become more effective, the ground-state energy decreasing below the unperturbed value. (author). 12 refs, 4 figs
Quadrupole formula for Kaluza-Klein modes in the braneworld
International Nuclear Information System (INIS)
Kinoshita, Shunichiro; Kudoh, Hideaki; Sendouda, Yuuiti; Sato, Katsuhiko
2005-01-01
The quadrupole formula in four-dimensional Einstein gravity is a useful tool to describe gravitational wave radiation. We derive the quadrupole formula for the Kaluza-Klein (KK) modes in the Randall-Sundrum braneworld model. The quadrupole formula provides a transparent representation of the exterior weak gravitational field induced by localized sources. We find that a general isolated dynamical source gives rise to the 1/r 2 correction to the leading 1/r gravitational field. We apply the formula to an evaluation of the effective energy carried by the KK modes from the viewpoint of an observer on the brane. Contrary to the ordinary gravitational waves (zero mode), the flux of the induced KK modes by the non-spherical part of the quadrupole moment vanishes at infinity and only the spherical part contributes to the flux. Since the effect of the KK modes appears in the linear order of the metric perturbations, the effective energy flux observed on the brane is not always positive, but can become negative depending on the motion of the localized sources
Pairing field and moments of inertia of superdeformed nuclei
International Nuclear Information System (INIS)
Chen Yongjing; Chen Yongshou; Xu Fuxin
2002-01-01
The authors have systematically analysed the dynamic moments of inertia of the experimental superdeformed (SD) bands observed in the A = 190, 150 and 60-80 mass regions as functions of rotational frequency. By combining the different mass regions, the dramatic features of the dynamic moments of inertia were found and explained based on the calculations of the pairing fields of SD nuclei with the anisotropic harmonic oscillator quadrupole pairing Hartree-Fock-Bogoliubov model
International Nuclear Information System (INIS)
Witte, N.S.; Shankar, R.
1999-01-01
We examine the Ising chain in a transverse field at zero temperature from the point of view of a family of moment formalisms based upon the cumulant generating function, where we find exact solutions for the generating functions and cumulants at arbitrary couplings and hence for both the ordered and disordered phases of the model. In a t-expansion analysis, the exact Horn-Weinstein function E(t) has cuts along an infinite set of curves in the complex Jt-plane which are confined to the left-hand half-plane ImJt < -((1)/(4)) for the phase containing the trial state (disordered), but are not so for the other phase (ordered). For finite couplings the expansion has a finite radius of convergence. Asymptotic forms for this function exhibit a crossover at the critical point, giving the excited state gap in the ground state sector for the disordered phase, and the first excited state gap in the ordered phase. Convergence of the t-expansion with respect to truncation order is found in the disordered phase right up to the critical point, for both the ground state energy and the excited state gap. However, convergence is found in only one of the connected moments expansions (CMX), the CMX-LT, and the ground state energy shows convergence right to the criticalpoint again, although to a limited accuracy
International Nuclear Information System (INIS)
Ghosh, Barnali; Raychaudhuri, A.K.; Siruguri, V.; Chatterji, Tapan; Thomas, Hansen; Mukovskii, Ya.M.
2013-01-01
Depending on the doping level x the hole-doped perovskite manganites, like La 1-x Ca x MnO 3 exhibit a wide variety of physical properties. These compounds lead their high sensitivity to thermodynamic variables like temperature, magnetic field and pressure. The structure can be modified by application of high pressure and it can be quantitative that changes the Mn-O bond length and increases the Mn-O-Mn bond angle. In some cases the pressure can bring about qualitative changes in the structure like change in the lattice structure or its symmetry. These structural factors can contribute to the effective electron transfer integral between Mn ions, which in turn can change the magnetic exchanges like the double-exchange as well as the super exchange. For low hole doping (0.15 ≤ x ≤ 0.2), the low temperature ground state is Ferromagnetic insulator (FMI). The ground state of the low doped manganite La 0.79 Ca 0.21 MnO 3 (LCMO) can be destabilized by external hydrostatic pressure. We have done electrical transport measurement under magnetic field and under high pressure for understanding the nature of the resulting phase(s) that arise from the applied hydrostatic pressure. We find that the metallic phase so created under pressure has no appreciable magnetoresistance (MR). The Neutron powder diffraction measurement done on D20 diffractometer (λ=1.3Å) at ILL, Grenoble, France under high hydrostatic pressure up to 10GPa shows that the pressure leads to a change in the crystal structure from orthorhombic to rhombohedral and leading to a change in magnetic structure also; and most importantly collapse of the magnetic moment to a low value that leads to absence of any MR under pressure induced metallization. (author)
Theory of nuclear magnetic moments - LT-35
Energy Technology Data Exchange (ETDEWEB)
Kerman, A. K.
1952-09-15
The purpose of these notes is to give an account of some attempts at interpreting the observed values of nuclear magnetic moments. There is no attempt at a complete summary of the field as that would take much more space than is used here. In many cases the arguments are only outlined and references are given for those interested in further details. A discussion of the theory of nuclear magnetic moments necessitates many excursions into the details of the nuclear models because the magnetic moments have a direct bearing on the validity of these models. However the main emphasis here is on those features which tend to explain the magnetic moments and other evidence is not discussed unless it has a direct bearing on the problem. In the first part of the discussion the Shell Model of the nucleus is used, as this model seems to correlate a large body of data relating to the heavier nuclei. Included here are the modifications proposed to explain the fact that the experimental magnetic moments do not fit quantitatively with the exact predictions of the Shell Model. The next sections deal with some of the more drastic modifications introduced to explain the large nuclear quadrupole moments and the effect of these modifications on the magnetic moments. Finally we turn to more detailed investigations of the light nuclei, in particular the - Conjugate nuclei. (author)
From ground state to fission fragments: A complex, multi-dimensional multi-path problem
International Nuclear Information System (INIS)
Moeller, P.; Nix, J.R.; Swiatecki, W.J.
1992-01-01
Experimental results on the fission properties of nuclei close to 264 Fm show sudden and large changes with a change of only one or two neutrons or protons. The nucleus 258 Fm, for instance, undergoes symmetric fission with a half-life of about 0.4 ms and a kinetic-energy distribution peaked at about 235 MeV whereas 256 Fm undergoes asymmetric fission with a half-life of about 3 h and a kinetic-energy distribution peaked at about 200 MeV. Qualitatively, these sudden changes have been postulated to be due to the emergence of fragment shells in symmetric-fission products close to 132 Sn. Here we present a quantitative calculation that shows where high-kinetic-energy symmetric fusion occurs and why it is associated with a sudden and large decrease in fission half-lives. We base our study on calculations of potential-energy surfaces in the macroscopic-microscopic model and a semi-empirical model for the nuclear inertia. We use the three-quadratic-surface parameterization to generate the shapes for which the potential-energy surfaces are calculated. The use of this parameterization and the use of the finite-range macroscopic model allows for the study of two touching spheres and similar shapes. Since these shapes are thought to correspond to the scission shapes for the high-kinetic-energy events it is of crucial importance that a continuous sequence of shapes leading from the nuclear ground state to these configurations can be studied within the framework of the model. We present the results of the calculations in terms of potential-energy surfaces and fission half-lives for heavy even nuclei. The surfaces are displayed in the form of contour diagrams as functions of two moments of the shape. They clearly show the appearance of a second fission valley, which leads to scission configurations close to tow touching spheres, for fissioning systems in the vicinity of 264 Fm
Li, Li; Nishihara, Sadafumi; Inoue, Katsuya; Kurmoo, Mohamedally
2016-03-21
We report the exceptional observation of two different magnetic ground states (MGS), spin glass (SG, T(B) = 7 K) and ferrimagnet (FI, T(C) = 18 K), for one crystal structure of [{Mn(II)(D/L-NH2ala)}3{Mn(III)(CN)6}]·3H2O obtained from [Mn(CN)6](3-) and D/L-aminoalanine, in contrast to one MGS for [{Mn(II)(L-NH2ala)}3{Cr(III)(CN)6}]·3H2O. They consist of three Mn(NH2ala) helical chains bridged by M(III)(CN)6 to give the framework with disordered water molecules in channels and between the M(III)(CN)6. Both MGS are characterized by a negative Weiss constant, bifurcation in ZFC-FC magnetizations, blocking of the moments, both components of the ac susceptibilities, and hysteresis. They differ in the critical temperatures, absolute magnetization for 5 Oe FC (lack of spontaneous magnetization for the SG), and the shapes of the hysteresis and coercive fields. While isotropic pressure increases both T(crit) and the magnetizations linearly and reversibly in each case, dehydration progressively transforms the FI into the SG as followed by concerted in situ magnetic measurements and single-crystal diffraction. The relative strengths of the two moderate Mn(III)-CN-Mn(II) antiferromagnetic (J1 and J2), the weak Mn(II)-OCO-Mn(II) (J3), and Dzyaloshinkii-Moriya antisymmetric (DM) interactions generate the two sets of characters. Examination of the bond lengths and angles for several crystals and their corresponding magnetic properties reveals a correlation between the distortion of Mn(III)(CN)6 and the MGS. SG is favored by higher magnetic anisotropy by less distorted Mn(III)(CN)6 in good accordance with the Mn-Cr system. This conclusion is also born out of the magnetization measurements on orientated single crystals with fields parallel and perpendicular to the unique c axis of the hexagonal space group.
International Nuclear Information System (INIS)
Yamanaka, Masanori; Honjo, Shinsuke; Kohmoto, Mahito
1996-01-01
We investigate one-dimensional strongly correlated electron models which have the resonating-valence-bond state as the exact ground state. The correlation functions are evaluated exactly using the transfer matrix method for the geometric representations of the valence-bond states. In this method, we only treat matrices with small dimensions. This enables us to give analytical results. It is shown that the correlation functions decay exponentially with distance. The result suggests that there is a finite excitation gap, and that the ground state is insulating. Since the corresponding noninteracting systems may be insulating or metallic, we can say that the gap originates from strong correlation. The persistent currents of the present models are also investigated and found to be exactly vanishing
Communication: On the isotope anomaly of nuclear quadrupole coupling in molecules
Filatov, Michael; Zou, Wenli; Cremer, Dieter
2012-10-01
The dependence of the nuclear quadrupole coupling constants (NQCC) on the interaction between electrons and a nucleus of finite size is theoretically analyzed. A deviation of the ratio of the NQCCs obtained from two different isotopomers of a molecule from the ratio of the corresponding bare nuclear electric quadrupole moments, known as quadrupole anomaly, is interpreted in terms of the logarithmic derivatives of the electric field gradient at the nuclear site with respect to the nuclear charge radius. Quantum chemical calculations based on a Dirac-exact relativistic methodology suggest that the effect of the changing size of the Au nucleus in different isotopomers can be observed for Au-containing molecules, for which the predicted quadrupole anomaly reaches values of the order of 0.1%. This is experimentally detectable and provides an insight into the charge distribution of non-spherical nuclei.
Mandrà, Salvatore; Zhu, Zheng; Katzgraber, Helmut G
2017-02-17
We study the performance of the D-Wave 2X quantum annealing machine on systems with well-controlled ground-state degeneracy. While obtaining the ground state of a spin-glass benchmark instance represents a difficult task, the gold standard for any optimization algorithm or machine is to sample all solutions that minimize the Hamiltonian with more or less equal probability. Our results show that while naive transverse-field quantum annealing on the D-Wave 2X device can find the ground-state energy of the problems, it is not well suited in identifying all degenerate ground-state configurations associated with a particular instance. Even worse, some states are exponentially suppressed, in agreement with previous studies on toy model problems [New J. Phys. 11, 073021 (2009)NJOPFM1367-263010.1088/1367-2630/11/7/073021]. These results suggest that more complex driving Hamiltonians are needed in future quantum annealing machines to ensure a fair sampling of the ground-state manifold.
Construction of ground-state preserving sparse lattice models for predictive materials simulations
Huang, Wenxuan; Urban, Alexander; Rong, Ziqin; Ding, Zhiwei; Luo, Chuan; Ceder, Gerbrand
2017-08-01
First-principles based cluster expansion models are the dominant approach in ab initio thermodynamics of crystalline mixtures enabling the prediction of phase diagrams and novel ground states. However, despite recent advances, the construction of accurate models still requires a careful and time-consuming manual parameter tuning process for ground-state preservation, since this property is not guaranteed by default. In this paper, we present a systematic and mathematically sound method to obtain cluster expansion models that are guaranteed to preserve the ground states of their reference data. The method builds on the recently introduced compressive sensing paradigm for cluster expansion and employs quadratic programming to impose constraints on the model parameters. The robustness of our methodology is illustrated for two lithium transition metal oxides with relevance for Li-ion battery cathodes, i.e., Li2xFe2(1-x)O2 and Li2xTi2(1-x)O2, for which the construction of cluster expansion models with compressive sensing alone has proven to be challenging. We demonstrate that our method not only guarantees ground-state preservation on the set of reference structures used for the model construction, but also show that out-of-sample ground-state preservation up to relatively large supercell size is achievable through a rapidly converging iterative refinement. This method provides a general tool for building robust, compressed and constrained physical models with predictive power.
Electromagnetic design of superconducting quadrupoles
Directory of Open Access Journals (Sweden)
L. Rossi
2006-10-01
Full Text Available We study how the critical gradient depends on the coil layout in a superconducting quadrupole for particle accelerators. We show that the results relative to a simple sector coil are well representative of the coil layouts that have been used to build several quadrupoles in the past 30 years. Using a semianalytical approach, we derive a formula that gives the critical gradient as a function of the coil cross-sectional area, of the magnet aperture, and of the superconducting cable parameters. This formula is used to evaluate the efficiency of several types of coil layouts (shell, racetrack, block, open midplane.
An online database of nuclear electromagnetic moments
International Nuclear Information System (INIS)
Mertzimekis, T.J.; Stamou, K.; Psaltis, A.
2016-01-01
Measurements of nuclear magnetic dipole and electric quadrupole moments are considered quite important for the understanding of nuclear structure both near and far from the valley of stability. The recent advent of radioactive beams has resulted in a plethora of new, continuously flowing, experimental data on nuclear structure – including nuclear moments – which hinders the information management. A new, dedicated, public and user friendly online database ( (http://magneticmoments.info)) has been created comprising experimental data of nuclear electromagnetic moments. The present database supersedes existing printed compilations, including also non-evaluated series of data and relevant meta-data, while putting strong emphasis on bimonthly updates. The scope, features and extensions of the database are reported.
Collisions involving energy transfer between atoms with large angular moments
International Nuclear Information System (INIS)
Vdovin, Yu.A.; Galitskij, V.M.
1975-01-01
Study is made of the collisions of excited and nonexcited atoms with a small resonance defect, assuming that the excited and ground states of each atom are bound via an allowed dipole transition and that intrinsic moments of states are great. In such an approximation the atomic interaction is defined by a dipole-dipole interaction operator. Equations for amplitudes are derived for two cases: (1) the first atom is in an excited state while the second is in the ground state and (2) the first atom is in the ground state while the second is in an excited state. The problem is solved in the approximation that the moments of the excited and ground states of each atom are equal. An expression for the excitation transfer cross section is written down. Analysis of this expression shows that the excitation transfer cross section at first increases with removal from the exact resonance and reaches resonance at lambda approximately 0.1 (lambda is a dimensionless parameter which is equal to the ratio of the resonance defect Δ to the interaction at spacings of the order of the Weisskopf radius). Only at lambda >0.16 does the cross section become smaller than the resonance one. This effect is due to the interaction Hamiltonian approximation adopted in the present study
Rathjen, C
2002-01-01
A method based on analytical formulas is described to calculate bending moments, stresses, and deformations of vacuum chambers and beam screens in dipole and in quadrupole fields during a magnet quench. Solutions are given for circular and racetrack shaped structures. Without the need of time consuming calculations the solutions enable a quick design and verification of vacuum chambers and beam screens.
On the theoretical description of nuclear quadrupole coupling in Π states of small molecules
Czech Academy of Sciences Publication Activity Database
Fišer, J.; Polák, Rudolf
2013-01-01
Roč. 425, NOV 2013 (2013), s. 126-133 ISSN 0301-0104 Institutional support: RVO:61388955 Keywords : Π States * Nuclear quadrupole coupling constant * Electric dipole moment Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.028, year: 2013
Towards {sup 6}Li-{sup 40}K ground state molecules
Energy Technology Data Exchange (ETDEWEB)
Brachmann, Johannes Felix Simon
2013-02-08
The production of a quantum gas with strong long - range dipolar interactions is a major scientific goal in the research field of ultracold gases. In their ro - vibrational ground state Li-K dimers possess a large permanent dipole moment, which could possibly be exploited for the realization of such a quantum gas. A production of these molecules can be achieved by the association of Li and K at a Feshbach resonance, followed by a coherent state transfer. In this thesis, detailed theoretical an experimental preparations to achieve state transfer by means of Stimulated Raman Adiabatic Passage (STIRAP) are described. The theoretical preparations focus on the selection of an electronically excited molecular state that is suitable for STIRAP transfer. In this context, molecular transition dipole moments for both transitions involved in STIRAP transfer are predicted for the first time. This is achieved by the calculation of Franck-Condon factors and a determination of the state in which the {sup 6}Li-{sup 40}K Feshbach molecules are produced. The calculations show that state transfer by use of a single STIRAP sequence is experimentally very well feasible. Further, the optical wavelengths that are needed to address the selected states are calculated. The high accuracy of the data will allow to carry out the molecular spectroscopy in a fast and efficient manner. Further, only a comparatively narrow wavelength tuneability of the spectroscopy lasers is needed. The most suitable Feshbach resonance for the production of {sup 6}Li-{sup 40}K molecules at experimentally manageable magnetic field strengths is occurring at 155 G. Experimentally, this resonance is investigated by means of cross-dimensional relaxation. The application of the technique at various magnetic field strengths in the vicinity of the 155 G Feshbach resonance allows a determination of the resonance position and width with so far unreached precision. This reveals the production of molecules on the atomic side
Gapless Spin-Liquid Ground State in the S =1 /2 Kagome Antiferromagnet
Liao, H. J.; Xie, Z. Y.; Chen, J.; Liu, Z. Y.; Xie, H. D.; Huang, R. Z.; Normand, B.; Xiang, T.
2017-03-01
The defining problem in frustrated quantum magnetism, the ground state of the nearest-neighbor S =1 /2 antiferromagnetic Heisenberg model on the kagome lattice, has defied all theoretical and numerical methods employed to date. We apply the formalism of tensor-network states, specifically the method of projected entangled simplex states, which combines infinite system size with a correct accounting for multipartite entanglement. By studying the ground-state energy, the finite magnetic order appearing at finite tensor bond dimensions, and the effects of a next-nearest-neighbor coupling, we demonstrate that the ground state is a gapless spin liquid. We discuss the comparison with other numerical studies and the physical interpretation of this result.
Extended random-phase approximation with three-body ground-state correlations
International Nuclear Information System (INIS)
Tohyama, M.; Schuck, P.
2008-01-01
An extended random-phase approximation (ERPA) which contains the effects of ground-state correlations up to a three-body level is applied to an extended Lipkin model which contains an additional particle-scattering term. Three-body correlations in the ground state are necessary to preserve the hermiticity of the Hamiltonian matrix of ERPA. Two approximate forms of ERPA which neglect the three-body correlations are also applied to investigate the importance of three-body correlations. It is found that the ground-state energy is little affected by the inclusion of the three-body correlations. On the contrary, three-body correlations for the excited states can become quite important. (orig.)
Quantum ground state and single-phonon control of a mechanical resonator.
O'Connell, A D; Hofheinz, M; Ansmann, M; Bialczak, Radoslaw C; Lenander, M; Lucero, Erik; Neeley, M; Sank, D; Wang, H; Weides, M; Wenner, J; Martinis, John M; Cleland, A N
2010-04-01
Quantum mechanics provides a highly accurate description of a wide variety of physical systems. However, a demonstration that quantum mechanics applies equally to macroscopic mechanical systems has been a long-standing challenge, hindered by the difficulty of cooling a mechanical mode to its quantum ground state. The temperatures required are typically far below those attainable with standard cryogenic methods, so significant effort has been devoted to developing alternative cooling techniques. Once in the ground state, quantum-limited measurements must then be demonstrated. Here, using conventional cryogenic refrigeration, we show that we can cool a mechanical mode to its quantum ground state by using a microwave-frequency mechanical oscillator-a 'quantum drum'-coupled to a quantum bit, which is used to measure the quantum state of the resonator. We further show that we can controllably create single quantum excitations (phonons) in the resonator, thus taking the first steps to complete quantum control of a mechanical system.
Learning Approach on the Ground State Energy Calculation of Helium Atom
International Nuclear Information System (INIS)
Shah, Syed Naseem Hussain
2010-01-01
This research investigated the role of learning approach on the ground state energy calculation of Helium atom in improving the concepts of science teachers at university level. As the exact solution of several particles is not possible here we used approximation methods. Using this method one can understand easily the calculation of ground state energy of any given function. Variation Method is one of the most useful approximation methods in estimating the energy eigen values of the ground state and the first few excited states of a system, which we only have a qualitative idea about the wave function.The objective of this approach is to introduce and involve university teacher in new research, to improve their class room practices and to enable teachers to foster critical thinking in students.
Van der Waals potential and vibrational energy levels of the ground state radon dimer
Sheng, Xiaowei; Qian, Shifeng; Hu, Fengfei
2017-08-01
In the present paper, the ground state van der Waals potential of the Radon dimer is described by the Tang-Toennies potential model, which requires five essential parameters. Among them, the two dispersion coefficients C6 and C8 are estimated from the well determined dispersion coefficients C6 and C8 of Xe2. C10 is estimated by using the approximation equation that C6C10/C82 has an average value of 1.221 for all the rare gas dimers. With these estimated dispersion coefficients and the well determined well depth De and Re the Born-Mayer parameters A and b are derived. Then the vibrational energy levels of the ground state radon dimer are calculated. 40 vibrational energy levels are observed in the ground state of Rn2 dimer. The last vibrational energy level is bound by only 0.0012 cm-1.
Probing the 8He ground state via the 8He(p,t)6He reaction
International Nuclear Information System (INIS)
Keeley, N.; Skaza, F.; Lapoux, V.; Alamanos, N.; Auger, F.; Beaumel, D.; Becheva, E.; Blumenfeld, Y.; Delaunay, F.; Drouart, A.; Gillibert, A.; Giot, L.; Kemper, K.W.; Nalpas, L.; Pakou, A.; Pollacco, E.C.; Raabe, R.; Roussel-Chomaz, P.; Rusek, K.; Scarpaci, J.-A.; Sida, J.-L.; Stepantsov, S.; Wolski, R.
2007-01-01
The weakly-bound 8 He nucleus exhibits a neutron halo or thick neutron skin and is generally considered to have an α+4n structure in its ground state, with the four valence neutrons each occupying 1p 3/2 states outside the α core. The 8 He(p,t) 6 He reaction is a sensitive probe of the ground state structure of 8 He, and we present a consistent analysis of new and existing data for this reaction at incident energies of 15.7 and 61.3A MeV, respectively. Our results are incompatible with the usual assumption of a pure (1p 3/2 ) 4 structure and suggest that other configurations such as (1p 3/2 ) 2 (1p 1/2 ) 2 may be present with significant probability in the ground state wave function of 8 He
Antibonding hole ground state in InAs quantum dot molecules
Energy Technology Data Exchange (ETDEWEB)
Planelles, Josep [Departament de Química Física i Analítica, Universitat Jaume I, E-12080, Castelló (Spain)
2015-01-22
Using four-band k⋅p Hamiltonians, we study how strain and position-dependent effective masses influence hole tunneling in vertically coupled InAs/GaAs quantum dots. Strain reduces the tunneling and hence the critical interdot distance required for the ground state to change from bonding to antibonding. Variable mass has the opposite effect and a rough compensation leaves little affected the critical bonding-to-antibonding ground state crossover. An alternative implementation of the magnetic field in the envelope function Hamiltonian is given which retrieves the experimental denial of possible after growth reversible magnetically induced bonding-to-antibonding ground state transition, predicted by the widely used Luttinger-Kohn Hamiltonian.
Exact ground-state correlation functions of an atomic-molecular Bose–Einstein condensate model
Links, Jon; Shen, Yibing
2018-05-01
We study the ground-state properties of an atomic-molecular Bose–Einstein condensate model through an exact Bethe Ansatz solution. For a certain range of parameter choices, we prove that the ground-state Bethe roots lie on the positive real-axis. We then use a continuum limit approach to obtain a singular integral equation characterising the distribution of these Bethe roots. Solving this equation leads to an analytic expression for the ground-state energy. The form of the expression is consistent with the existence of a line of quantum phase transitions, which has been identified in earlier studies. This line demarcates a molecular phase from a mixed phase. Certain correlation functions, which characterise these phases, are then obtained through the Hellmann–Feynman theorem.
Natoli, Calogero R.; Krüger, Peter; Bartolomé, Juan; Bartolomé, Fernando
2018-04-01
We determine the magnetic ground state of the FePc molecule on Au-supported thin films based on the observed values of orbital anisotropy and spectroscopic x-ray magnetic circular dichroism (XMCD) measurements at the Fe K and L edges. Starting from ab initio molecular orbital multiplet calculations for the isolated molecule, we diagonalize the spin-orbit interaction in the subspace spanned by the three lowest spin triplet states of 3A2 g and 3Eg symmetry in the presence of a saturating magnetic field at a polar angle θ with respect to the normal to the plane of the film, plus an external perturbation representing the effect of the molecules in the stack on the FePc molecule under consideration. We find that the orbital moment of the ground state strongly depends on the magnetic field direction in agreement with the sum rule analysis of the L23-edge XMCD data. We calculate integrals over the XMCD spectra at the Fe K and L23 edges as used in the sum rules and explicitly show that they agree with the expectation values of the orbital moment and effective spin moment of the ground state. On the basis of this analysis, we can rule out alternative candidates proposed in the literature.
Electromagnetic moments and effective operators in nuclei near and far from the stability line
International Nuclear Information System (INIS)
Matsuta, Kensaku; Minamisono, Tadanori; Ogawa, Yoko; Miyake, Toru; Morishita, Akio; Sato, Kazunori; Momota, Sadao; Nojiri, Yoichi; Mihara, Mototsugu; Fukuda, Mitsunori; Zhu, Sheng-Yung; Onishi, Takashi; Sasaki, Makoto; Yamaguchi, Takayuki; Minamisono, Kei; Akai, Hisazumi; Atsushi, Kitagawa; Torikoshi, Masami; Kanazawa, Mitsutaka; Nishio, Teiji; Koda, Shigeru; Otsubo, Tatashi; Fukuda, Shigekazu; Tanihata, Isao; Yoshida, Koichi; Ozawa, Akira; Kitagawa, Hisashi; Sagawa, Hiroyuki; Hanna, Stanley S.; Alonso, Jose R.; Krebs, Gary F.; Symons, T. James M.; Osaka-RIKEN-HIMAC Collaboration
2003-12-01
Quenching of neutron effective charge has been observed by measuring the quadrupole moment of 16 N. Moreover, the neutron effective charge may be quenched in the quadrupole moment of 21 F. This quenching of effective charges is discussed in terms of the overlap integrals of the wave functions of the valence nucleons and the core. Effective g-factors may be required to explain the large spin expectation value for the mass number 9 mirror nuclei, deduced from the iso-scalar magnetic moment
Stability of the electroweak ground state in the Standard Model and its extensions
International Nuclear Information System (INIS)
Di Luzio, Luca; Isidori, Gino; Ridolfi, Giovanni
2016-01-01
We review the formalism by which the tunnelling probability of an unstable ground state can be computed in quantum field theory, with special reference to the Standard Model of electroweak interactions. We describe in some detail the approximations implicitly adopted in such calculation. Particular attention is devoted to the role of scale invariance, and to the different implications of scale-invariance violations due to quantum effects and possible new degrees of freedom. We show that new interactions characterized by a new energy scale, close to the Planck mass, do not invalidate the main conclusions about the stability of the Standard Model ground state derived in absence of such terms.
Stability of the electroweak ground state in the Standard Model and its extensions
Energy Technology Data Exchange (ETDEWEB)
Di Luzio, Luca, E-mail: diluzio@ge.infn.it [Dipartimento di Fisica, Università di Genova and INFN, Sezione di Genova, Via Dodecaneso 33, I-16146 Genova (Italy); Isidori, Gino [Department of Physics, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland); Ridolfi, Giovanni [Dipartimento di Fisica, Università di Genova and INFN, Sezione di Genova, Via Dodecaneso 33, I-16146 Genova (Italy)
2016-02-10
We review the formalism by which the tunnelling probability of an unstable ground state can be computed in quantum field theory, with special reference to the Standard Model of electroweak interactions. We describe in some detail the approximations implicitly adopted in such calculation. Particular attention is devoted to the role of scale invariance, and to the different implications of scale-invariance violations due to quantum effects and possible new degrees of freedom. We show that new interactions characterized by a new energy scale, close to the Planck mass, do not invalidate the main conclusions about the stability of the Standard Model ground state derived in absence of such terms.
Stability of the electroweak ground state in the Standard Model and its extensions
Directory of Open Access Journals (Sweden)
Luca Di Luzio
2016-02-01
Full Text Available We review the formalism by which the tunnelling probability of an unstable ground state can be computed in quantum field theory, with special reference to the Standard Model of electroweak interactions. We describe in some detail the approximations implicitly adopted in such calculation. Particular attention is devoted to the role of scale invariance, and to the different implications of scale-invariance violations due to quantum effects and possible new degrees of freedom. We show that new interactions characterized by a new energy scale, close to the Planck mass, do not invalidate the main conclusions about the stability of the Standard Model ground state derived in absence of such terms.
Ground State of Bosons in Bose-Fermi Mixture with Spin-Orbit Coupling
Sakamoto, Ryohei; Ono, Yosuke; Hatsuda, Rei; Shiina, Kenta; Arahata, Emiko; Mori, Hiroyuki
2017-07-01
We study an effect of spin-1/2 fermions on the ground state of a Bose system with equal Rashba and Dresselhaus spin-orbit coupling. By using mean-field and tight-binding approximations, we show the ground state phase diagram of the Bose system in the spin-orbit coupled Bose-Fermi mixture and find that the characteristic phase domain, where a spin current of fermions may be induced, can exist even in the presence of a significantly large number of fermions.
Numerical study of the t-J model: Exact ground state and flux phases
International Nuclear Information System (INIS)
Hasegawa, Y.; Poilblanc, D.
1990-01-01
Strongly correlated 2D electrons described by the t-J model are investigated numerically. Exact ground state for one and two holes in a finite cluster with periodic boundary conditions are obtained by using the Lanczos algorithm. The effects of Coulomb repulsion of the holes on the nearest neighbor sites are taken into account. Commensurate flux phases are investigated for the same size of clusters. They are shown to be a good approximation for the ground state specially in the intermediate value of J/t. (author). 21 refs, 3 figs
Fission barriers and asymmetric ground states in the relativistic mean-field theory
International Nuclear Information System (INIS)
Rutz, K.; Reinhard, P.G.; Greiner, W.
1995-01-01
The symmetric and asymmetric fission path for 240 Pu, 232 Th and 226 Ra is investigated within the relativistic mean-field model. Standard parametrizations which are well fitted to nuclear ground-state properties are found to deliver reasonable qualitative and quantitative features of fission, comparable to similar nonrelativistic calculations. Furthermore, stable octupole deformations in the ground states of radium isotopes are investigated. They are found in a series of isotopes, qualitatively in agreement with nonrelativistic models. But the quantitative details differ amongst the models and between the various relativistic parametrizations. (orig.)
Numerical study of ground state and low lying excitations of quantum antiferromagnets
International Nuclear Information System (INIS)
Trivedi, N.; Ceperley, D.M.
1989-01-01
The authors have studied, via Green function Monte Carlo (GFMC), the S = 1/2 Heisenberg quantum antiferromagnet in two dimensions on a square lattice. They obtain the ground state energy with only statistical errors E 0 /J = -0.6692(2), the staggered magnetization m † = 0.31(2), and from the long wave length behavior of the structure factor, the spin wave velocity c/c o = 1.14(5). They show that the ground state wave function has long range pair correlations arising from the zero point motion of spin waves
Ground state energy and width of 7He from 8Li proton knockout
International Nuclear Information System (INIS)
Denby, D. H.; DeYoung, P. A.; Hall, C. C.; Baumann, T.; Bazin, D.; Spyrou, A.; Breitbach, E.; Howes, R.; Brown, J.; Frank, N.; Gade, A.; Mosby, S. M.; Peters, W. A.; Thoennessen, M.; Hinnefeld, J.; Hoffman, C. R.; Jenson, R. A.; Luther, B.; Olson, C. W.; Schiller, A.
2008-01-01
The ground state energy and width of 7 He has been measured with the Modular Neutron Array (MoNA) and superconducting dipole Sweeper magnet experimental setup at the National Superconducting Cyclotron Laboratory. 7 He was produced by proton knockout from a secondary 8 Li beam. The measured decay energy spectrum is compared to simulations based on Breit-Wigner line shape with an energy-dependent width for the resonant state. The energy of the ground state is found to be 400(10) keV with a full-width at half-maximum of 125( -15 +40 ) keV
The ground-state phase diagrams of the spin-3/2 Ising model
International Nuclear Information System (INIS)
Canko, Osman; Keskin, Mustafa
2003-01-01
The ground-state spin configurations are obtained for the spin-3/2 Ising model Hamiltonian with bilinear and biquadratic exchange interactions and a single-ion crystal field. The interactions are assumed to be only between nearest-neighbors. The calculated ground-state phase diagrams are presented on diatomic lattices, such as the square, honeycomb and sc lattices, and triangular lattice in the (Δ/z vertical bar J vertical bar ,K/ vertical bar J vertical bar) and (H/z vertical bar J vertical bar, K/ vertical bar J vertical bar) planes
Singlet Ground State Magnetism: III Magnetic Excitons in Antiferromagnetic TbP
DEFF Research Database (Denmark)
Knorr, K.; Loidl, A.; Kjems, Jørgen
1981-01-01
The dispersion of the lowest magnetic excitations of the singlet ground state system TbP has been studied in the antiferromagnetic phase by inelastic neutron scattering. The magnetic exchange interaction and the magnetic and the rhombohedral molecular fields have been determined.......The dispersion of the lowest magnetic excitations of the singlet ground state system TbP has been studied in the antiferromagnetic phase by inelastic neutron scattering. The magnetic exchange interaction and the magnetic and the rhombohedral molecular fields have been determined....
Ground-state properties of third-row elements with nonlocal density functionals
International Nuclear Information System (INIS)
Bagno, P.; Jepsen, O.; Gunnarsson, O.
1989-01-01
The cohesive energy, the lattice parameter, and the bulk modulus of third-row elements are calculated using the Langreth-Mehl-Hu (LMH), the Perdew-Wang (PW), and the gradient expansion functionals. The PW functional is found to give somewhat better results than the LMH functional and both are found to typically remove half the errors in the local-spin-density (LSD) approximation, while the gradient expansion gives worse results than the local-density approximation. For Fe both the LMH and PW functionals correctly predict a ferromagnetic bcc ground state, while the LSD approximation and the gradient expansion predict a nonmagnetic fcc ground state
International Nuclear Information System (INIS)
Fuchs, J; Duffy, G J; Rowlands, W J; Lezama, A; Hannaford, P; Akulshin, A M
2007-01-01
We present an experimental study of sub-natural width resonances in fluorescence from a collimated beam of 6 Li atoms excited on the D 1 and D 2 lines by a bichromatic laser field. We show that in addition to ground-state Zeeman coherence, coherent population oscillations between ground and excited states contribute to the sub-natural resonances. High-contrast resonances of electromagnetically induced transparency and electromagnetically induced absorption due to both effects, i.e., ground-state Zeeman coherence and coherent population oscillations, are observed
On the ground state of the two-dimensional non-ideal Bose gas
International Nuclear Information System (INIS)
Lozovik, Yu.E.; Yudson, V.I.
1978-01-01
The theory of the ground state of the two-dimensional non-ideal Bose gas is presented. The conditions for the validity of the ladder and the Bogolubov approximations are derived. These conditions ensure the existence of a Bose condensate in the ground state of two-dimensional systems. These conditions are different from the corresponding conditions for the three-dimensional case. The connection between the effective interaction and the two-dimensional scattering amplitude at some characteristic energy kappa 2 /2m (not equal to 0) is obtained (f(kappa = 0) = infinity in the two-dimensional case). (Auth.)
Ground-state configuration of neutron-rich Aluminum isotopes through Coulomb Breakup
Directory of Open Access Journals (Sweden)
Chakraborty S.
2014-03-01
Full Text Available Neutron-rich 34,35Al isotopes have been studied through Coulomb excitation using LAND-FRS setup at GSI, Darmstadt. The method of invariant mass analysis has been used to reconstruct the excitation energy of the nucleus prior to decay. Comparison of experimental CD cross-section with direct breakup model calculation with neutron in p3/2 orbital favours 34Al(g.s⊗νp3/2 as ground state configuration of 35Al. But ground state configuration of 34Al is complicated as evident from γ-ray spectra of 33Al after Coulomb breakup of 34Al.
Trapping cold ground state argon atoms for sympathetic cooling of molecules
Edmunds, P. D.; Barker, P. F.
2014-01-01
We trap cold, ground-state, argon atoms in a deep optical dipole trap produced by a build-up cavity. The atoms, which are a general source for the sympathetic cooling of molecules, are loaded in the trap by quenching them from a cloud of laser-cooled metastable argon atoms. Although the ground state atoms cannot be directly probed, we detect them by observing the collisional loss of co-trapped metastable argon atoms using a new type of parametric loss spectroscopy. Using this technique we als...
International Nuclear Information System (INIS)
Chakraborty, S.; Datta Pramanik, U.; Chatterjee, S.
2013-01-01
The region of the nuclear chart around neutron magic number, N∼20 and proton number (Z), 10≤ Z≤12 is known as the Island of Inversion. The valance neutron(s) of these nuclei, even in their ground state, are most likely occupying the upper pf orbitals which are normally lying above sd orbitals, N∼20 shell closure. Nuclei like 34,35 Al are lying at the boundary of this Island of Inversion. Little experimental information about their ground state configuration are available in literature
Ziegler, Tom; Krykunov, Mykhaylo; Autschbach, Jochen
2014-09-09
The random phase approximation (RPA) equation of adiabatic time dependent density functional ground state response theory (ATDDFT) has been used extensively in studies of excited states. It extracts information about excited states from frequency dependent ground state response properties and avoids, thus, in an elegant way, direct Kohn-Sham calculations on excited states in accordance with the status of DFT as a ground state theory. Thus, excitation energies can be found as resonance poles of frequency dependent ground state polarizability from the eigenvalues of the RPA equation. ATDDFT is approximate in that it makes use of a frequency independent energy kernel derived from the ground state functional. It is shown in this study that one can derive the RPA equation of ATDDFT from a purely variational approach in which stationary states above the ground state are located using our constricted variational DFT (CV-DFT) method and the ground state functional. Thus, locating stationary states above the ground state due to one-electron excitations with a ground state functional is completely equivalent to solving the RPA equation of TDDFT employing the same functional. The present study is an extension of a previous work in which we demonstrated the equivalence between ATDDFT and CV-DFT within the Tamm-Dancoff approximation.
Some fundamental properties of the ground state of atoms and molecules
International Nuclear Information System (INIS)
Lieb, E.H.
1986-01-01
This paper studies the ground states of atoms and molecules in quantum mechanics and reports on some mathematically rigourous results pertaining to the matter. The non-relativistic Hamiltonian for a molecule in the static nucleus approximation is presented along with notations
Search for 12 C+ 12 C clustering in 24 Mg ground state
Indian Academy of Sciences (India)
Home; Journals; Pramana – Journal of Physics; Volume 88; Issue 2. Search for 12C+12C clustering in 24Mg ground state. B N JOSHI ARUN K JAIN D C BISWAS B V JOHN Y K GUPTA L S DANU R P VIND G K PRAJAPATI S MUKHOPADHYAY A SAXENA. Regular Volume 88 Issue 2 February 2017 Article ID 29 ...
A Rigorous Investigation on the Ground State of the Penson-Kolb Model
Yang, Kai-Hua; Tian, Guang-Shan; Han, Ru-Qi
2003-05-01
By using either numerical calculations or analytical methods, such as the bosonization technique, the ground state of the Penson-Kolb model has been previously studied by several groups. Some physicists argued that, as far as the existence of superconductivity in this model is concerned, it is canonically equivalent to the negative-U Hubbard model. However, others did not agree. In the present paper, we shall investigate this model by an independent and rigorous approach. We show that the ground state of the Penson-Kolb model is nondegenerate and has a nonvanishing overlap with the ground state of the negative-U Hubbard model. Furthermore, we also show that the ground states of both the models have the same good quantum numbers and may have superconducting long-range order at the same momentum q = 0. Our results support the equivalence between these models. The project partially supported by the Special Funds for Major State Basic Research Projects (G20000365) and National Natural Science Foundation of China under Grant No. 10174002
A projection gradient method for computing ground state of spin-2 Bose–Einstein condensates
Energy Technology Data Exchange (ETDEWEB)
Wang, Hanquan, E-mail: hanquan.wang@gmail.com [School of Statistics and Mathematics, Yunnan University of Finance and Economics, Kunming, Yunnan Province, 650221 (China); Yunnan Tongchang Scientific Computing and Data Mining Research Center, Kunming, Yunnan Province, 650221 (China)
2014-10-01
In this paper, a projection gradient method is presented for computing ground state of spin-2 Bose–Einstein condensates (BEC). We first propose the general projection gradient method for solving energy functional minimization problem under multiple constraints, in which the energy functional takes real functions as independent variables. We next extend the method to solve a similar problem, where the energy functional now takes complex functions as independent variables. We finally employ the method into finding the ground state of spin-2 BEC. The key of our method is: by constructing continuous gradient flows (CGFs), the ground state of spin-2 BEC can be computed as the steady state solution of such CGFs. We discretized the CGFs by a conservative finite difference method along with a proper way to deal with the nonlinear terms. We show that the numerical discretization is normalization and magnetization conservative and energy diminishing. Numerical results of the ground state and their energy of spin-2 BEC are reported to demonstrate the effectiveness of the numerical method.
Lower bounds for the ground states of He-isoelectronic series
International Nuclear Information System (INIS)
Fraga, Serafin
1981-01-01
A formulation, based on the concept of null local kinetic energy regions, has been developed for the determination of lower bounds for the ground state of a two-electron atom. Numerical results, obtained from Hartree-Fock functions, are presented for the elements He through Kr of the two-electron series
Ground states and formal duality relations in the Gaussian core model
Cohn, H.; Kumar, A.; Schürmann, A.
2009-01-01
We study dimensional trends in ground states for soft-matter systems. Specifically, using a high-dimensional version of Parrinello-Rahman dynamics, we investigate the behavior of the Gaussian core model in up to eight dimensions. The results include unexpected geometric structures, with surprising
Experimental Insights into Ground-State Selection of Quantum XY Pyrochlores
Hallas, Alannah M.; Gaudet, Jonathan; Gaulin, Bruce D.
2018-03-01
Extensive experimental investigations of the magnetic structures and excitations in the XY pyrochlores have been carried out over the past decade. Three families of XY pyrochlores have emerged: Yb2B2O7, Er2B2O7, and, most recently, [Formula: see text]Co2F7. In each case, the magnetic cation (either Yb, Er, or Co) exhibits XY anisotropy within the local pyrochlore coordinates, a consequence of crystal field effects. Materials in these families display rich phase behavior and are candidates for exotic ground states, such as quantum spin ice, and exotic ground-state selection via order-by-disorder mechanisms. In this review, we present an experimental summary of the ground-state properties of the XY pyrochlores, including evidence that they are strongly influenced by phase competition. We empirically demonstrate the signatures for phase competition in a frustrated magnet: multiple heat capacity anomalies, suppressed TN or TC, sample- and pressure-dependent ground states, and unconventional spin dynamics.
On the topological ground state of E-infinity spacetime and the super string connection
International Nuclear Information System (INIS)
El Naschie, M.S.
2007-01-01
There are at present a huge number of valid super string ground states, making the one corresponding to our own universe extremely hard to determine. Therefore it may come as quite a surprise that it is a rather simple undertaking to determine the exact topological ground state of E-infinity Cantorian spacetime theory. Similar to the ground state of the Higgs for E-infinity, the expectation value of the topological ground state is non-zero and negative. Its value is given exactly by -bar o -∼ n(1/φ) n =-(4+φ 3 ) where φ=(5-1)/2 and n represents an integer Menger-Uhryson dimension running from n=0 to n=-∼. Recalling that the average dimension of ε (∼) is given by ∼ =4+φ 3 , one could interpret this result as saying that our E-infinity spacetime may be viewed as an in itself closed manifold given by the remarkable equation: + =zeroThus in a manner of speaking, the universe could have spontaneously tunnelled into existence from virtual nothingness
Search for 12 C+ 12 C clustering in 24 Mg ground state
Indian Academy of Sciences (India)
In the backdrop of many models, the heavy cluster structure of the ground state of 24 Mg has been probed experimentally for the first time using the heavy cluster knockout reaction 24 Mg( 12 C, 212 C) 12 C in thequasifree scattering kinematic domain. In the ( 12 C, 212 C) reaction, the direct 12 C-knockout cross-section was ...
Ground state properties of the bond alternating spin-1/2 anisotropic Heisenberg chain
Directory of Open Access Journals (Sweden)
S. Paul
2017-06-01
Full Text Available Ground state properties, dispersion relations and scaling behaviour of spin gap of a bond alternating spin-1/2 anisotropic Heisenberg chain have been studied where the exchange interactions on alternate bonds are ferromagnetic (FM and antiferromagnetic (AFM in two separate cases. The resulting models separately represent nearest neighbour (NN AFM-AFM and AFM-FM bond alternating chains. Ground state energy has been estimated analytically by using both bond operator and Jordan-Wigner representations and numerically by using exact diagonalization. Dispersion relations, spin gap and several ground state orders have been obtained. Dimer order and string orders are found to coexist in the ground state. Spin gap is found to develop as soon as the non-uniformity in alternating bond strength is introduced in the AFM-AFM chain which further remains non-zero for the AFM-FM chain. This spin gap along with the string orders attribute to the Haldane phase. The Haldane phase is found to exist in most of the anisotropic region similar to the isotropic point.
Relativistic analysis of nuclear ground state densities at 135 to 200 ...
Indian Academy of Sciences (India)
fitting of differential cross-section and analyzing power, and the appearance of wine-bottle- ... So, the effect of different nuclear density distributions is quite conspicuous in the relativistic ap- proach. Hence, we have analyzed five different nuclear ground state .... The NEG and FNEG densities have been used to see the effect.
Quantum double-well chain: Ground-state phases and applications to hydrogen-bonded materials
International Nuclear Information System (INIS)
Wang, X.; Campbell, D.K.; Gubernatis, J.E.
1994-01-01
Extrapolating the results of hybrid quantum Monte Carlo simulations to the zero temperature and infinite-chain-length limits, we calculate the ground-state phase diagram of a system of quantum particles on a chain of harmonically coupled, symmetric, quartic double-well potentials. We show that the ground state of this quantum chain depends on two parameters, formed from the ratios of the three natural energy scales in the problem. As a function of these two parameters, the quantum ground state can exhibit either broken symmetry, in which the expectation values of the particle's coordinate are all nonzero (as would be the case for a classical chain), or restored symmetry, in which the expectation values of the particle's coordinate are all zero (as would be the case for a single quantum particle). In addition to the phase diagram as a function of these two parameters, we calculate the ground-state energy, an order parameter related to the average position of the particle, and the susceptibility associated with this order parameter. Further, we present an approximate analytic estimate of the phase diagram and discuss possible physical applications of our results, emphasizing the behavior of hydrogen halides under pressure
Reactive ground-state pathways are not ubiquitous in red/green cyanobacteriochromes.
Chang, Che-Wei; Gottlieb, Sean M; Kim, Peter W; Rockwell, Nathan C; Lagarias, J Clark; Larsen, Delmar S
2013-09-26
Recent characterization of the red/green cyanobacteriochrome (CBCR) NpR6012g4 revealed a high quantum yield for its forward photoreaction [J. Am. Chem. Soc. 2012, 134, 130-133] that was ascribed to the activity of hidden, productive ground-state intermediates. The dynamics of the pathways involving these ground-state intermediates was resolved with femtosecond dispersed pump-dump-probe spectroscopy, the first such study reported for any CBCR. To address the ubiquity of such second-chance initiation dynamics (SCID) in CBCRs, we examined the closely related red/green CBCR NpF2164g6 from Nostoc punctiforme. Both NpF2164g6 and NpR6012g4 use phycocyanobilin as the chromophore precursor and exhibit similar excited-state dynamics. However, NpF2164g6 exhibits a lower quantum yield of 32% for the generation of the isomerized Lumi-R primary photoproduct, compared to 40% for NpR6012g4. This difference arises from significantly different ground-state dynamics between the two proteins, with the SCID mechanism deactivated in NpF2164g6. We present an integrated inhomogeneous target model that self-consistently fits the pump-probe and pump-dump-probe signals for both forward and reverse photoreactions in both proteins. This work demonstrates that reactive ground-state intermediates are not ubiquitous phenomena in CBCRs.
Ground state structures and properties of Si3Hn (n= 1–6) clusters
Indian Academy of Sciences (India)
The ground state structures and properties of Si3H (1 ≤ ≤ 6) clusters have been calculated using Car–Parrinello molecular dynamics with simulated annealing and steepest descent optimization methods. We have studied cohesive energy per particle and first excited electronic level gap of the clusters as a function of ...
Soluble and stable heptazethrenebis(dicarboximide) with a singlet open-shell ground state
Sun, Zhe; Huang, Kuo-Wei; Wu, Jishan
2011-01-01
A soluble and stable heptazethrene derivative was synthesized and characterized for the first time. This molecule exhibits a singlet biradical character in the ground state, which is the first case among zethrene homologue series. Exceptional stability of this heptazethrenebis(dicarboximide) raises the likelihood of its practical applications in materials science. © 2011 American Chemical Society.
A projection gradient method for computing ground state of spin-2 Bose–Einstein condensates
International Nuclear Information System (INIS)
Wang, Hanquan
2014-01-01
In this paper, a projection gradient method is presented for computing ground state of spin-2 Bose–Einstein condensates (BEC). We first propose the general projection gradient method for solving energy functional minimization problem under multiple constraints, in which the energy functional takes real functions as independent variables. We next extend the method to solve a similar problem, where the energy functional now takes complex functions as independent variables. We finally employ the method into finding the ground state of spin-2 BEC. The key of our method is: by constructing continuous gradient flows (CGFs), the ground state of spin-2 BEC can be computed as the steady state solution of such CGFs. We discretized the CGFs by a conservative finite difference method along with a proper way to deal with the nonlinear terms. We show that the numerical discretization is normalization and magnetization conservative and energy diminishing. Numerical results of the ground state and their energy of spin-2 BEC are reported to demonstrate the effectiveness of the numerical method
Long-range interactions of excited He atoms with ground-state noble-gas atoms
Zhang, J.-Y.; Qian, Ying; Schwingenschlö gl, Udo; Yan, Z.-C.
2013-01-01
The dispersion coefficients C6, C8, and C10 for long-range interactions of He(n1,3S) and He(n1,3P), 2≤n≤10, with the ground-state noble-gas atoms Ne, Ar, Kr, and Xe are calculated by summing over the reduced matrix elements of multipole transition
A nonlinear programming approach to lower bounds for the ground-state energy of helium
International Nuclear Information System (INIS)
Porras, I.; Feldmann, D.M.; King, F.W.
1999-01-01
Lower-bound estimates for the ground-state energy of the helium atom are determined using nonlinear programming techniques. Optimized lower bounds are determined for single-particle, radially correlated, and general correlated wave functions. The local nature of the method employed makes it a very severe test of the accuracy of the wave function
Soluble and stable heptazethrenebis(dicarboximide) with a singlet open-shell ground state
Sun, Zhe
2011-08-10
A soluble and stable heptazethrene derivative was synthesized and characterized for the first time. This molecule exhibits a singlet biradical character in the ground state, which is the first case among zethrene homologue series. Exceptional stability of this heptazethrenebis(dicarboximide) raises the likelihood of its practical applications in materials science. © 2011 American Chemical Society.
Ground-state energy of an exciton-(LO) phonon system in a parabolic quantum well
Gerlach, B.; Wüsthoff, J.; Smondyrev, M. A.
1999-12-01
This paper presents a variational study of the ground-state energy of an exciton-(LO) phonon system, which is spatially confined to a quantum well. The exciton-phonon interaction is of Fröhlich type, the confinement potentials are assumed to be parabolic functions of the coordinates. Making use of functional integral techniques, the phonon part of the problem can be eliminated exactly, leading us to an effective two-particle system, which has the same spectral properties as the original one. Subsequently, Jensen's inequality is applied to obtain an upper bound on the ground-state energy. The main intention of this paper is to analyze the influence of the quantum-well-induced localization of the exciton on its ground-state energy (or its binding energy, respectively). To do so, we neglect any mismatch of the masses or the dielectric constants, but admit an arbitrary strength of the confinement potentials. Our approach allows for a smooth interpolation of the ultimate limits of vanishing and infinite confinement, corresponding to the cases of a free three-dimensional and a free two-dimensional exciton-phonon system. The interpolation formula for the ground-state energy bound corresponds to similar formulas for the free polaron or the free exciton-phonon system. These bounds in turn are known to compare favorably with all previous ones, which we are aware of.
Barbosa, Marcelo
A review about the nuclear properties, namely the nuclear moments (magnetic dipole moment and electric quadrupole moment) and their interaction with electromagnetic fields external to the nucleus (hyperfine interactions), as well as the angular distribution of radiation produced by $\\gamma$-decay, is presented. A detailed description about the theory of Perturbed Angular Correlations was done, including the comparison between $\\gamma-\\gamma$- correlations and $e^{-}- \\gamma$ correlations. For dynamic nuclear interactions, an introduction to the theory of stochastic states in PAC was performed. We focused on ab-initio implementation of observables for analyzing fluctuating quadrupole hyperfine interactions on time dependent perturbed angular correlations experiments. The development of computacional codes solving the full problem, adapted to fit data obtained on single crystals or polycrystals for two-state transient fields with any axial symmetry and orientation was the main purpose of this work. The final pa...
Origin-independent calculation of quadrupole intensities in X-ray spectroscopy
International Nuclear Information System (INIS)
Bernadotte, Stephan; Atkins, Andrew J.; Jacob, Christoph R.
2012-01-01
For electronic excitations in the ultraviolet and visible range of the electromagnetic spectrum, the intensities are usually calculated within the dipole approximation, which assumes that the oscillating electric field is constant over the length scale of the transition. For the short wavelengths used in hard X-ray spectroscopy, the dipole approximation may not be adequate. In particular, for metal K-edge X-ray absorption spectroscopy (XAS), it becomes necessary to include higher-order contributions. In quantum-chemical approaches to X-ray spectroscopy, these so-called quadrupole intensities have so far been calculated by including contributions depending on the square of the electric-quadrupole and magnetic-dipole transition moments. However, the resulting quadrupole intensities depend on the choice of the origin of the coordinate system. Here, we show that for obtaining an origin-independent theory, one has to include all contributions that are of the same order in the wave vector consistently. This leads to two additional contributions depending on products of the electric-dipole and electric-octupole and of the electric-dipole and magnetic-quadrupole transition moments, respectively. We have implemented such an origin-independent calculation of quadrupole intensities in XAS within time-dependent density-functional theory, and demonstrate its usefulness for the calculation of metal and ligand K-edge XAS spectra of transition metal complexes.
International Nuclear Information System (INIS)
Furukawa, Y.; Kumagai, K.; Lascialfari, A.; Aldrovandi, S.; Borsa, F.; Sessoli, R.; Gatteschi, D.
2001-01-01
The magnetic molecular cluster [Fe 8 (N 3 C 6 H 15 ) 6 O 2 (OH) 12 ] 8+ [Br 8 ·9H 2 O] 8- , in short Fe8, has been investigated at low temperature by 1 H-NMR and relaxation measurements. Some measurements of 2 D-NMR in partially deuterated Fe8 clusters will also be reported. Upon decreasing temperature the NMR spectra display a very broad and structured signal which is the result of the internal local fields at the proton sites due to the local moments of the Fe(III) ions in the total S=10 magnetic ground state. The proton and deuteron NMR spectra have been analyzed and the different resonance peaks have been attributed to the different proton groups in the molecule. The simulation of the spectra by using a dipolar hyperfine field and the accepted model for the orientation of the Fe(III) local moments do not agree with the experiments even when the magnitude of the local Fe(III) moments is allowed to vary. It is concluded that a positive contact hyperfine interaction of the same order of magnitude as the dipolar interaction is present for all proton sites except the water molecules. The temperature and magnetic field dependence of the nuclear spin-lattice relaxation rate is ascribed to the fluctuations of the local Fe(III) moments, which follow rigidly the fluctuations of the total ground state magnetization of the nanomagnet. By using a simple model already utilized for the Mn12 cluster, we derive the value of the spin phonon coupling constant which determines the lifetime broadening of the different magnetic quantum number m substates of the S=10 ground state. It is shown that the lifetime broadening decreases rapidly on lowering the temperature. When the lifetime becomes longer than the reciprocal of the frequency shift of the proton lines a structure emerges in the NMR spectrum reflecting the ''frozen'' local moment configuration
Assembling Transgender Moments
Greteman, Adam J.
2017-01-01
In this article, the author seeks to assemble moments--scholarly, popular, and aesthetic--in order to explore the possibilities that emerge as moments collect in education's encounters with the needs, struggles, and possibilities of transgender lives and practices. Assembling moments, the author argues, illustrates the value of "moments"…
Quadrupole collectivity in {sup 128}Cd
Energy Technology Data Exchange (ETDEWEB)
Boenig, Esther Sabine
2014-07-07
The regions around shell closures, especially around doubly magic nuclei, are of major interest in nuclear structure physics, as they provide a perfect test for nuclear structure theory. The neutron-rich Cd isotopes in the region of {sup 132}Sn are only two protons away from the shell closure at Z=50 and in close proximity to the N=82 magic number. Nevertheless they show an irregular behaviour regarding the excitation energy of the first excited 2{sup +} state. This is not reproduced by shell model calculations, which is astonishing due to the proximity of the shell closures. In order to shed light on the much discussed region around doubly magic {sup 132}Sn, a Coulomb excitation experiment of {sup 128}Cd has been performed at REX-ISOLDE, CERN. The reduced transition strength B(E2;0{sup +}{sub gs} → 2{sup +}{sub 1}), which is a measure of collectivity, and the spectroscopic quadrupole moment Q{sub s}(2{sup +}{sub 1}) as a measure of deformation could be determined for the first time. The results are shown as the continuation of already measured neutron-rich Cd isotopes and are compared to both beyond mean field and shell model calculations, which give different predictions for these observables.
Permanent electric dipole moments of PtX (X = H, F, Cl, Br, and I) by the composite approach
Deng, Dan; Lian, Yongqin; Zou, Wenli
2017-11-01
Using the FPD composite approach of Peterson et. al. we calculate the permanent electric dipole moments of PtX (X = H, F, Cl, Br, and I) at the equilibrium geometries of their ground states. The dipole moment of PtF is estimated to be 3.421 Debye, being very close to the experimental value of 3.42(6) Debye. This research also suggests the ordering of dipole moments of PtX being proportional to the electronegativity of X.
Nuclear quadrupole resonance of arsenolite
International Nuclear Information System (INIS)
Madarazo, R.
1988-01-01
A pulsed Nuclear Quadrupole Resonance (NQR) spectrometer was constructed using imported Matec units. Peripherical components were specially assembled and tested for the implantation of the spin-echo technique in the Laboratorio de Centros de Cor of IFUSP. The R.F. operation range is from 50 to 1 ) and spin-spin (T 2 ) relaxation times were carried out at room temperature in arsenolite. The 75 As NQR frequency measured at room temperature is 116.223 MHz. (author) [pt
Determination of anisotropic dipole moments in self-assembled quantum dots using Rabi oscillations
Muller, Andreas; Wang, Qu-Quan; Bianucci, Pablo; Xue, Qi-Kun; Shih, Chih-Kang
2004-03-01
By investigating the polarization-dependent Rabi oscillations using photoluminescence spectroscopy, we determined the respective transition dipole moments of the two excited excitonic states |Ex> and |Ey> of a single self-assembled quantum dot that are nondegenerate due to shape anisotropy. We find that the ratio of the two dipole moments is close to the physical elongation ratio of the quantum dot. We also measured the ground state radiative lifetimes of several quantum dots. The dipole moments calculated from the latter are in reasonable agreement with the dipole moments determined from the periodicity of the Rabi oscillations.
International Nuclear Information System (INIS)
Nomura, K.; Vretenar, D.; Niksic, T.; Otsuka, T.; Shimizu, N.
2011-01-01
Microscopic energy density functionals have become a standard tool for nuclear structure calculations, providing an accurate global description of nuclear ground states and collective excitations. For spectroscopic applications, this framework has to be extended to account for collective correlations related to restoration of symmetries broken by the static mean field, and for fluctuations of collective variables. In this paper, we compare two approaches to five-dimensional quadrupole dynamics: the collective Hamiltonian for quadrupole vibrations and rotations and the interacting boson model (IBM). The two models are compared in a study of the evolution of nonaxial shapes in Pt isotopes. Starting from the binding energy surfaces of 192,194,196 Pt, calculated with a microscopic energy density functional, we analyze the resulting low-energy collective spectra obtained from the collective Hamiltonian, and the corresponding IBM Hamiltonian. The calculated excitation spectra and transition probabilities for the ground-state bands and the γ-vibration bands are compared to the corresponding sequences of experimental states.
Ground-state kinetics of bistable redox-active donor-acceptor mechanically interlocked molecules.
Fahrenbach, Albert C; Bruns, Carson J; Li, Hao; Trabolsi, Ali; Coskun, Ali; Stoddart, J Fraser
2014-02-18
The ability to design and confer control over the kinetics of theprocesses involved in the mechanisms of artificial molecular machines is at the heart of the challenge to create ones that can carry out useful work on their environment, just as Nature is wont to do. As one of the more promising forerunners of prototypical artificial molecular machines, chemists have developed bistable redox-active donor-acceptor mechanically interlocked molecules (MIMs) over the past couple of decades. These bistable MIMs generally come in the form of [2]rotaxanes, molecular compounds that constitute a ring mechanically interlocked around a dumbbell-shaped component, or [2]catenanes, which are composed of two mechanically interlocked rings. As a result of their interlocked nature, bistable MIMs possess the inherent propensity to express controllable intramolecular, large-amplitude, and reversible motions in response to redox stimuli. In this Account, we rationalize the kinetic behavior in the ground state for a large assortment of these types of bistable MIMs, including both rotaxanes and catenanes. These structures have proven useful in a variety of applications ranging from drug delivery to molecular electronic devices. These bistable donor-acceptor MIMs can switch between two different isomeric states. The favored isomer, known as the ground-state co-conformation (GSCC) is in equilibrium with the less favored metastable state co-conformation (MSCC). The forward (kf) and backward (kb) rate constants associated with this ground-state equilibrium are intimately connected to each other through the ground-state distribution constant, KGS. Knowing the rate constants that govern the kinetics and bring about the equilibration between the MSCC and GSCC, allows researchers to understand the operation of these bistable MIMs in a device setting and apply them toward the construction of artificial molecular machines. The three biggest influences on the ground-state rate constants arise from
Kowalska, M
2006-01-01
Studies in regions of the nuclear chart in which the model predictions of properties of nuclei fail can bring a better understanding of the strong interaction in the nuclear medium. To such regions belongs the so called "island of inversion" centered around Ne, Na and Mg isotopes with 20 neutrons in which unexpected ground-state spins, large deformations and dense low-energy spectra appear. This is a strong argument that the magic N=20 is not a closed shell in this area. In this thesis investigations of isotope shifts of stable $^{24-26}$Mg, as well as spins and magnetic moments of short-lived $^{29,31}$Mg are presented. The successful studies were performed at the ISOLDE facility at CERN using collinear laser and $\\beta$-NMR spectroscopy techniques. The isotopes were investigated as single-charged ions in the 280 nm transition from the atomic ground state $^2\\!$S$_{1/2}$ to one of the two lowest excited states $^2\\!$P$_{1/2 ,\\,3/2}$ using continuous wave laser beams. The isotope-shift measurements with fluor...
International Nuclear Information System (INIS)
Molayem, M.; Tayebi-Rad, Gh.; Esmaeli, L.; Namiranian, A.; Fouladvand, M. E.; Neek-Amal, M.
2006-01-01
Using the diffusion quantum monte Carlo method, the ground state energy of an Hydrogen atom confined in a carbon nano tube and a C60 molecule is calculated. For Hydrogen atom confined in small diameter tubes, the ground state energy shows significant deviation from a free Hydrogen atom, while with increasing the diameter this deviation tends to zero.
Luo, Ding; Lee, Sangsu; Zheng, Bin; Sun, Zhe; Zeng, Wangdong; Huang, Kuo-Wei; Furukawa, Ko; Kim, Dongho; Webster, Richard D.; Wu, Jishan
2014-01-01
and showed different ground states. Based on variable-temperature NMR/ESR measurements and density functional theory calculations, it was found that the indolo[2,3-b]carbazole derivative 1 is a persistent singlet biradical in the ground state with a moderate
Theory of Nonlinear Dispersive Waves and Selection of the Ground State
International Nuclear Information System (INIS)
Soffer, A.; Weinstein, M.I.
2005-01-01
A theory of time-dependent nonlinear dispersive equations of the Schroedinger or Gross-Pitaevskii and Hartree type is developed. The short, intermediate and large time behavior is found, by deriving nonlinear master equations (NLME), governing the evolution of the mode powers, and by a novel multitime scale analysis of these equations. The scattering theory is developed and coherent resonance phenomena and associated lifetimes are derived. Applications include Bose-Einstein condensate large time dynamics and nonlinear optical systems. The theory reveals a nonlinear transition phenomenon, 'selection of the ground state', and NLME predicts the decay of excited state, with half its energy transferred to the ground state and half to radiation modes. Our results predict the recent experimental observations of Mandelik et al. in nonlinear optical waveguides
The influence of nonlocal hybridization on ground-state properties of the Falicov-Kimball model
International Nuclear Information System (INIS)
Farkasovsky, Pavol
2005-01-01
The density matrix renormalization group is used to examine effects of nonlocal hybridization on ground-state properties of the Falicov-Kimball model (FKM) in one dimension. Special attention is devoted to the problem of hybridization-induced insulator-metal transition. It is shown that the picture of insulator-metal transitions found for the FKM with nonlocal hybridization strongly differs from one found for the FKM without hybridization (as well as with local hybridization). The effect of nonlocal hybridization is so strong that it can induce the insulator-metal transition, even in the half-filled band case where the ground states of the FKM without hybridization are insulating for all finite Coulomb interactions. Outside the half-filled band case the metal-insulator transition driven by pressure is found for finite values of nonlocal hybridization
Rayleigh approximation to ground state of the Bose and Coulomb glasses
Ryan, S. D.; Mityushev, V.; Vinokur, V. M.; Berlyand, L.
2015-01-01
Glasses are rigid systems in which competing interactions prevent simultaneous minimization of local energies. This leads to frustration and highly degenerate ground states the nature and properties of which are still far from being thoroughly understood. We report an analytical approach based on the method of functional equations that allows us to construct the Rayleigh approximation to the ground state of a two-dimensional (2D) random Coulomb system with logarithmic interactions. We realize a model for 2D Coulomb glass as a cylindrical type II superconductor containing randomly located columnar defects (CD) which trap superconducting vortices induced by applied magnetic field. Our findings break ground for analytical studies of glassy systems, marking an important step towards understanding their properties. PMID:25592417
The Ground State Energy of a Dilute Bose Gas in Dimension $n\\geq 3$
DEFF Research Database (Denmark)
Aaen, Anders Gottfred
We consider a Bose gas in spatial dimension n≥3 with a repulsive, radially symmetric two-body potential V. In the limit of low density ρ, the ground state energy per particle in the thermodynamic limit is shown to be (n−2)|Sn−1|an−2ρ, where |Sn−1| denotes the surface measure of the unit sphere...... in Rn, and a is the scattering length of V. Furthermore, for smooth and compactly supported two-body potentials, we derive an upper bound to the ground state energy with a correction term (1+γ)8π4a6ρ2|ln(a4ρ)| in 4 dimensions, where 0... dimensions. Finally, we use a grand canonical construction to give a simplified proof of the second order upper bound to the Lee-Huang-Yang formula, a result first obtained by Yau and Yin. We also test this method in 4 dimensions, but with a negative outcome....
Ground state properties of new element Z=113 and its alpha decay chain
International Nuclear Information System (INIS)
Tai Fei; Chen Dinghan; Xu Chang; Ren Zhongzhou
2005-01-01
The authors investigate the ground state properties of the new element 278 113 and of the α-decay chain with different models, where the new element Z=113 has been produced at RIKEN in Japan by cold-fusion reaction. The experimental decay energies are reproduced by the deformed relativistic mean-field model, by the Skyrme-Hartree-Fock (SHF) model, and by the macroscopic-microscopic model. Theoretical half-lives also reasonably agree with the data. Calculations further show that prolate deformation is important for the ground states of the nuclei in the α-decay chain of 278 113. The common points and differences among different models are compared and discussed. (author)
The ground state energy of 3He droplet in the LOCV framework
International Nuclear Information System (INIS)
Modarres, M.; Motahari, S.; Rajabi, A.
2012-01-01
The (extended) lowest order constrained variational method was used to calculate the ground state energy of liquid helium 3 ( 3 He) droplets at zero temperature. Different types of density distribution profiles, such as the Gaussian, the Quasi-Gaussian and the Woods-Saxon were used. It was shown that at least, on average, near 20 3 He atoms are needed to get the bound state for 3 He liquid droplet. Depending on the choice of the density profiles and the atomic radius of 3 He, the above estimate can increase to 300. Our calculated ground state energy and the number of atoms in liquid 3 He droplet were compared with those of Variational Monte Carlo method, Diffusion Monte Carlo method and Density Functional Theory, for which a reasonable agreement was found.
Non-Gaussian ground-state deformations near a black-hole singularity
Hofmann, Stefan; Schneider, Marc
2017-03-01
The singularity theorem by Hawking and Penrose qualifies Schwarzschild black holes as geodesic incomplete space-times. Albeit this is a mathematically rigorous statement, it requires an operational framework that allows us to probe the spacelike singularity via a measurement process. Any such framework necessarily has to be based on quantum theory. As a consequence, the notion of classical completeness needs to be adapted to situations where the only adequate description is in terms of quantum fields in dynamical space-times. It is shown that Schwarzschild black holes turn out to be complete when probed by self-interacting quantum fields in the ground state and in excited states. The measure for populating quantum fields on hypersurfaces in the vicinity of the black-hole singularity goes to zero towards the singularity. This statement is robust under non-Gaussian deformations of and excitations relative to the ground state. The physical relevance of different completeness concepts for black holes is discussed.
The resonating group method three cluster approach to the ground state 9 Li nucleus structure
International Nuclear Information System (INIS)
Filippov, G.F.; Pozdnyakov, Yu.A.; Terenetsky, K.O.; Verbitsky, V.P.
1994-01-01
The three-cluster approach for light atomic nuclei is formulated in frame of the algebraic version of resonating group method. Overlap integral and Hamiltonian matrix elements on generating functions are obtained for 9 Li nucleus. All permissible by Pauli principle 9 Li different cluster nucleon permutations were taken into account in the calculations. The results obtained can be easily generalised on any three-cluster system up to 12 C. Matrix elements obtained in the work were used in the variational calculations of the ground state energetic and geometric 9 Li characteristics. It is shown that 9 Li ground state is not adequate to the shell model limit and has pronounced three-cluster structure. (author). 16 refs., 4 tab., 2 figs
Stability of quantum-dot excited-state laser emission under simultaneous ground-state perturbation
Energy Technology Data Exchange (ETDEWEB)
Kaptan, Y., E-mail: yuecel.kaptan@physik.tu-berlin.de; Herzog, B.; Schöps, O.; Kolarczik, M.; Woggon, U.; Owschimikow, N. [Institut für Optik und Atomare Physik, Technische Universität Berlin, Berlin (Germany); Röhm, A.; Lingnau, B.; Lüdge, K. [Institut für Theoretische Physik, Technische Universität Berlin, Berlin (Germany); Schmeckebier, H.; Arsenijević, D.; Bimberg, D. [Institut für Festkörperphysik, Technische Universität Berlin, Berlin (Germany); Mikhelashvili, V.; Eisenstein, G. [Technion Institute of Technology, Faculty of Electrical Engineering, Haifa (Israel)
2014-11-10
The impact of ground state amplification on the laser emission of In(Ga)As quantum dot excited state lasers is studied in time-resolved experiments. We find that a depopulation of the quantum dot ground state is followed by a drop in excited state lasing intensity. The magnitude of the drop is strongly dependent on the wavelength of the depletion pulse and the applied injection current. Numerical simulations based on laser rate equations reproduce the experimental results and explain the wavelength dependence by the different dynamics in lasing and non-lasing sub-ensembles within the inhomogeneously broadened quantum dots. At high injection levels, the observed response even upon perturbation of the lasing sub-ensemble is small and followed by a fast recovery, thus supporting the capacity of fast modulation in dual-state devices.
Hylleraas-Configuration Interaction study of the 1S ground state of the negative Li ion.
Sims, James S
2017-12-28
In a previous work Sims and Hagstrom [J. Chem. Phys. 140, 224312 (2014)] reported Hylleraas-Configuration Interaction (Hy-CI) method variational calculations for the neutral atom and positive ion 1 S ground states of the beryllium isoelectronic sequence. The Li - ion, nominally the first member of this series, has a decidedly different electronic structure. This paper reports the results of a large, comparable calculation for the Li - ground state to explore how well the Hy-CI method can represent the more diffuse L shell of Li - which is representative of the Be(2sns) excited states as well. The best non-relativistic energy obtained was -7.500 776 596 hartree, indicating that 10 - 20 nh accuracy is attainable in Hy-CI and that convergence of the r 12 r 34 double cusp is fast and that this correlation type can be accurately represented within the Hy-CI model.
Influence of mass-asymmetry and ground state spin on fission fragment angular distributions
International Nuclear Information System (INIS)
Thomas, R.G.; Biswas, D.C.; Saxena, A.; Pant, L.M.; Nayak, B.K.; Vind, R.P.; Sahu, P.K.; Sinha, Shrabani; Choudhury, R.K.
2001-01-01
The strong influence of the target or/and projectile ground state spin on the anomalously large anisotropies of fission fragments produced in the heavy-ion induced fission of actinide targets were reported earlier. Interestingly, all those systems studied were having a mass asymmetry greater than the Businaro-Gallone critical asymmetry and hence the presence of pre-equilibrium fission was unambiguously ruled out. The observed anisotropies were successfully explained using the ECD-K-States model. It is of interest to know the influence of the target/projectile ground state spin on systems having an entrance channel mass asymmetry less than the critical value where pre-equilibrium fission cannot be ignored. With this motivation we performed measurements of fission fragment angular distributions of the 16 O+ 235 U (spin=7/2) system
Ground state of a hydrogen ion molecule immersed in an inhomogeneous electron gas
International Nuclear Information System (INIS)
Diaz-Valdes, J.; Gutierrez, F.A.; Matamala, A.R.; Denton, C.D.; Vargas, P.; Valdes, J.E.
2007-01-01
In this work we have calculated the ground state energy of the hydrogen molecule, H 2 + , immersed in the highly inhomogeneous electron gas around a metallic surface within the local density approximation. The molecule is perturbed by the electron density of a crystalline surface of Au with the internuclear axis parallel to the surface. The surface spatial electron density is calculated through a linearized band structure method (LMTO-DFT). The ground state of the molecule-ion was calculated using the Born-Oppenheimer approximation for a fixed-ion while the screening effects of the inhomogeneous electron gas are depicted by a Thomas-Fermi like electrostatic potential. We found that within our model the molecular ion dissociates at the critical distance of 2.35a.u. from the first atomic layer of the solid
Green function iterative solution of ground state wave function for Yukawa potential
International Nuclear Information System (INIS)
Zhang Zhao
2003-01-01
The newly developed single trajectory quadrature method is applied to solve central potentials. First, based on the series expansion method an exact analytic solution of the ground state for Hulthen potential and an approximate solution for Yukawa potential are obtained respectively. Second, the newly developed iterative method based on Green function defined by quadratures along the single trajectory is applied to solve Yukawa potential using the Coulomb solution and Hulthen solution as the trial functions respectively. The results show that a more proper choice of the trial function will give a better convergence. To further improve the convergence the iterative method is combined with the variational method to solve the ground state wave function for Yukawa potential, using variational solutions of the Coulomb and Hulthen potentials as the trial functions. The results give much better convergence. Finally, the obtained critical screen coefficient is applied to discuss the dissociate temperature of J/ψ in high temperature QGP
Mandal, Sudhansu S.; Mukherjee, Sutirtha; Ray, Koushik
2018-03-01
A method for determining the ground state of a planar interacting many-electron system in a magnetic field perpendicular to the plane is described. The ground state wave-function is expressed as a linear combination of a set of basis functions. Given only the flux and the number of electrons describing an incompressible state, we use the combinatorics of partitioning the flux among the electrons to derive the basis wave-functions as linear combinations of Schur polynomials. The procedure ensures that the basis wave-functions form representations of the angular momentum algebra. We exemplify the method by deriving the basis functions for the 5/2 quantum Hall state with a few particles. We find that one of the basis functions is precisely the Moore-Read Pfaffian wave function.
International Nuclear Information System (INIS)
Farasat, M; Golzan, M M; Shojaei, S H R; Morini, F; Deleuze, M S
2016-01-01
The electronic structure, electron binding energy spectrum and (e, 2e) momentum distributions of aniline have been theoretically predicted at an electron impact energy of 1.500 keV on the basis of Born–Oppenheimer molecular dynamical simulations, in order to account for thermally induced nuclear motions in the initial electronic ground state. Most computed momentum profiles are rather insensitive to thermally induced alterations of the molecular structure, with the exception of the profiles corresponding to two ionization bands at electron binding energies comprised between ∼10.0 and ∼12.0 eV (band C) and between ∼16.5 and ∼20.0 eV (band G). These profiles are found to be strongly influenced by nuclear dynamics in the electronic ground state, especially in the low momentum region. The obtained results show that thermal averaging smears out most generally the spectral fingerprints that are induced by nitrogen inversion. (paper)
Global optimization of proteins using a dynamical lattice model: Ground states and energy landscapes
Dressel, F.; Kobe, S.
2004-01-01
A simple approach is proposed to investigate the protein structure. Using a low complexity model, a simple pairwise interaction and the concept of global optimization, we are able to calculate ground states of proteins, which are in agreement with experimental data. All possible model structures of small proteins are available below a certain energy threshold. The exact lowenergy landscapes for the trp cage protein (1L2Y) is presented showing the connectivity of all states and energy barriers.
Prospects for studies of ground-state proton decays with the Holifield Radioactive Ion Beam Facility
International Nuclear Information System (INIS)
Toth, K.S.
1994-01-01
By using radioactive ions from the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory it should be possible to identify many new ground-state proton emitters in the mass region from Sn to Pb. During this production and search process the limits of stability on the proton-rich side of the nuclidic chart will be delineated for a significant fraction of medium-weight elements and our understanding of the proton-emission process will be expanded and improved
Ground-state triply and doubly heavy baryons in a relativistic three-quark model
International Nuclear Information System (INIS)
Martynenko, A.P.
2008-01-01
Mass spectra of the ground-state baryons consisting of three or two heavy (b or c) and one light (u,d,s) quarks are calculated in the framework of the relativistic quark model and the hyperspherical expansion. The predictions of masses of the triply and doubly heavy baryons are obtained by employing the perturbation theory for the spin-independent and spin-dependent parts of the three-quark Hamiltonian
Structural Distortion Stabilizing the Antiferromagnetic and Semiconducting Ground State of BaMn2As2
Directory of Open Access Journals (Sweden)
Ekkehard Krüger
2016-09-01
Full Text Available We report evidence that the experimentally found antiferromagnetic structure as well as the semiconducting ground state of BaMn 2 As 2 are caused by optimally-localized Wannier states of special symmetry existing at the Fermi level of BaMn 2 As 2 . In addition, we find that a (small tetragonal distortion of the crystal is required to stabilize the antiferromagnetic semiconducting state. To our knowledge, this distortion has not yet been established experimentally.
On the ground state and infrared divergences of Goldstone bosons in two dimensions
International Nuclear Information System (INIS)
Jevicki, A.
1977-01-01
The O(N) invariant Goldstone field theory is studied in two dimensions where rigorous theorems forbid the occurrence of spontaneous symmetry breaking. It is agreed that for computation of the ground state energy at weak coupling it is still the standard Goldstone perturbation expansion that is applicable. This happens due to cancellation of infrared divergences and this fact is demonstrated explicitly at the two-loop level. (Auth.)
Ground state representation of the infinite one-dimensional Heisenberg ferromagnet. Pt. 2
International Nuclear Information System (INIS)
Babbitt, D.; Thomas, L.
1977-01-01
In its ground state representation, the infinite, spin 1/2 Heisenberg chain provides a model for spin wave scattering, which entails many features of the quantum mechanical N-body problem. Here, we give a complete eigenfunction expansion for the Hamiltonian of the chain in this representation, for all numbers of spin waves. Our results resolve the questions of completeness and orthogonality of the eigenfunctions given by Bethe for finite chains, in the infinite volume limit. (orig.) [de
Czech Academy of Sciences Publication Activity Database
Vackář, Jiří; Šipr, Ondřej; Šimůnek, Antonín
2008-01-01
Roč. 77, č. 4 (2008), 045112/1-045112/6 ISSN 1098-0121 R&D Projects: GA AV ČR IAA100100514; GA AV ČR(CZ) IAA100100637 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z10100521 Keywords : core levels * ab-initio calculations * electronic states * ground state properties Subject RIV: BE - Theoretical Physics Impact factor: 3.322, year: 2008
Engineering an all-optical route to ultracold molecules in their vibronic ground state
Koch, Christiane P.; Moszynski, Robert
2008-01-01
We propose an improved photoassociation scheme to produce ultracold molecules in their vibronic ground state for the generic case where non-adiabatic effects facilitating transfer to deeply bound levels are absent. Formation of molecules is achieved by short laser pulses in a Raman-like pump-dump process where an additional near-infrared laser field couples the excited state to an auxiliary state. The coupling due to the additional field effectively changes the shape of the excited state pote...
International Nuclear Information System (INIS)
Radozycki, T.
1990-01-01
The properties of the virtual cloud around the hydrogen atom in the ground state are studied with the use of quantum field theory methods. The relativistic expression for the electromagnetic energy density around the atom, with the electron spin taken into account, is obtained. The distribution of the angular momentum contained in the cloud and the self-interaction kernel for the electrons bound in atom are also investigated. (author)
Ground-state projection multigrid for propagators in 4-dimensional SU(2) gauge fields
International Nuclear Information System (INIS)
Kalkreuter, T.
1991-09-01
The ground-state projection multigrid method is studied for computations of slowly decaying bosonic propagators in 4-dimensional SU(2) lattice gauge theory. The defining eigenvalue equation for the restriction operator is solved exactly. Although the critical exponent z is not reduced in nontrivial gauge fields, multigrid still yields considerable speedup compared with conventional relaxation. Multigrid is also able to outperform the conjugate gradient algorithm. (orig.)
Ground State of the Universe and the Cosmological Constant. A Nonperturbative Analysis.
Husain, Viqar; Qureshi, Babar
2016-02-12
The physical Hamiltonian of a gravity-matter system depends on the choice of time, with the vacuum naturally identified as its ground state. We study the expanding Universe with scalar field in the volume time gauge. We show that the vacuum energy density computed from the resulting Hamiltonian is a nonlinear function of the cosmological constant and time. This result provides a new perspective on the relation between time, the cosmological constant, and vacuum energy.
Induced quadrupolar singlet ground state of praseodymium in a modulated pyrochlore
van Duijn, J.; Kim, K. H.; Hur, N.; Ruiz-Bustos, R.; Adroja, D. T.; Bridges, F.; Daoud-Aladine, A.; Fernandez-Alonso, F.; Wen, J. J.; Kearney, V.; Huang, Q. Z.; Cheong, S.-W.; Perring, T. G.; Broholm, C.
2017-09-01
The complex structure and magnetism of Pr2 -xBixRu2O7 was investigated by neutron scattering and extended x-ray absorption fine structure. Pr has an approximate doublet ground state and the first excited state is a singlet. While the B -site (Ru) is well ordered throughout, this is not the case for the A -site (Pr/Bi). A broadened distribution for the Pr-O2 bond length at low temperature indicates the Pr environment varies from site to site even for x =0 . The environment about the Bi site is highly disordered ostensibly due to the 6 s lone pairs on Bi3 +. Correspondingly, we find that the non-Kramers doublet ground-state degeneracy, otherwise anticipated for Pr in the pyrochlore structure, is lifted so as to produce a quadrupolar singlet ground state with a spatially varying energy gap. For x =0 , below TN, the Ru sublattice orders antiferromagnetically, with propagation vector k =(0 ,0 ,0 ) as for Y2Ru2O7 . No ordering associated with the Pr sublattice is observed down to 100 mK. The low-energy magnetic response of Pr2 -xBixRu2O7 features a broad spectrum of magnetic excitations associated with inhomogeneous splitting of the Pr quasidoublet ground state. For x =0 (x =0.97 ), the spectrum is temperature dependent (independent). It appears disorder associated with Bi alloying enhances the inhomogeneous Pr crystal-field level splitting so that intersite interactions become irrelevant for x =0.97 . The structural complexity for the A -site may be reflected in the hysteretic uniform magnetization of B -site ruthenium in the Néel phase.
Stable π-Extended p -Quinodimethanes: Synthesis and Tunable Ground States
Zeng, Zebing
2014-12-18
© 2014 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. p-Quinodimethane (p-QDM) is a highly reactive hydrocarbon showing large biradical character in the ground state. It has been demonstrated that incorporation of the p-QDM moiety into an aromatic hydrocarbon framework could lead to new π-conjugated systems with significant biradical character and unique optical, electronic and magnetic properties. On the other hand, the extension of p-QDM is expected to result in molecules with even larger biradical character and higher reactivity. Therefore, the synthesis of stable π-extended p-QDMs is very challenging. In this Personal Account we will briefly discuss different stabilizing strategies and synthetic methods towards stable π-extended p-QDMs with tunable ground states and physical properties, including two types of polycyclic hydrocarbons: (1) tetrabenzo-Tschitschibabin\\'s hydrocarbons, and (2) tetracyano-rylenequinodimethanes. We will discuss how the aromaticity, substituents and steric hindrance play important roles in determining their ground states and properties. Incorporation of the p-quinodimethane moiety into aromatic hydrocarbon frameworks can lead to new π-conjugated systems with significant biradical character and unique optical, electronic and magnetic properties. Furthermore, the extension of p-QDM is expected to result in molecules with even larger biradical character and higher reactivity. In this Personal Account, different stabilizing strategies and synthetic methods towards stable π-extended p-QDMs with tunable ground states and physical properties are briefly discussed, including the roles of aromaticity, substituents and steric hindrance.
The electromagnetic multipole moments of the charged open-flavor {Z}_{\\bar{c}q} states
Azizi, K.; Özdem, U.
2018-05-01
The electromagnetic multipole moments of the open-flavor {Z}\\bar{cq} states are investigated by assuming a diquark–antidiquark picture for their internal structure and quantum numbers {J}{PC}={1}+- for their spin-parity. In particular, their magnetic and quadrupole moments are extracted in the framework of light-cone QCD sum rule by the help of the photon distribution amplitudes. The electromagnetic multipole moments of the open-flavor {Z}\\bar{cq} states are important dynamical observables, which encode valuable information on their underlying structure. The results obtained for the magnetic moments of different structures are considerably large and can be measured in future experiments. We obtain very small values for the quadrupole moments of {Z}\\bar{cq} states indicating a nonspherical charge distribution.
Aaron, Jean-Jacques; Diabou Gaye, Mame; Párkányi, Cyril; Cho, Nam Sook; Von Szentpály, László
1987-01-01
The ground-state dipole moments of seven biologically important purines (purine, 6-chloropurine, 6-mercaptopurine, hypoxanthine, theobromine, theophylline and caffeine) were determined at 25°C in acetic acid (all the above compounds with the exception of purine) and in ethyl acetate (purine, theophylline and caffeine). Because of its low solubility, it was not possible to measure the dipole moment of uric acid. The first excited singlet-state dipole moments were obtained on the basis of the Bakhshiev and Chamma—Viallet equations using the variation of the Stokes shift with the solvent dielectric constant-refractive index term. The theoretical dipole moments for all the purines listed above and including uric acid were calculated by combining the use of the PPP (π-LCI-SCF-MO) method for the π-contribution to the overall dipole moment with the σ-contribution obtained as a vector sum of the σbond moments and group moments. The experimental and theoretical values were compared with the data available in the literature for some of the purines under study. For several purines, the calculations were carried out for different tautomeric forms. Excited singlet-state dipole moments are smaller than the ground-state values by 0.8 to 2.2 Debye units for all purines under study with the exception of 6-chloropurine. The effects of the structure upon the ground- and excited-state dipole moments of the purines are discussed.
Ground state structure of U2Mo: static and lattice dynamics study
International Nuclear Information System (INIS)
Mukherjee, D.; Sahoo, B.D.; Joshi, K.D.; Kaushik, T.C.
2016-01-01
According to experimental reports, the ground state stable structure of U 2 Mo is tetragonal. However, various theoretical studies performed in past do not get tetragonal phase as the stable structure at ambient conditions. Therefore, the ground state structure of U 2 Mo is still unresolved. In an attempt to understand the ground state properties of this system, we have carried out first principle electronic band structure calculations. The structural stability analysis carried out using evolutionary structure search algorithm in conjunction with ab-inito method shows that a hexagonal structure (space group P6/mmm) is the lowest enthalpy structure at ambient condition and remains stable upto 200 GPa. The elastic and lattice dynamical stability further supports the stability of this phase at ambient condition. Further, using the 0 K calculations in conjunction with finite temperature corrections, we have derived the isotherm and shock adiabat (Hugoniot) of this material. Various equilibrium properties such as ambient pressure volume, bulk modulus, pressure derivative of bulk modulus etc. are derived from equation of state. (author)
Effect of the ground state correlations in the density distribution and zero point fluctuations
International Nuclear Information System (INIS)
Barranco, F.; Broglia, R.A.
1985-01-01
The existence of collective vibrations in the spectrum implies that the description of the ground state in an independent particle model must be corrected. This is because of the zero point fluctuations induced by the collective vibrations, so that ground state correlations have to be included. These are taken into account via the diagrammatic expansion of the Nuclear Field Theory, giving place to a renormalization in the different properties of the ground state. As far as the density distribution is concerned, in a NFT consistent calculation, the largest contributions arise from diagrams that cannot be expressed in terms of backward going amplitudes of the phonon RPA wave function. For a given multipolarity the main correction comes from the low lying state. The giant resonance is of smaller relevance since it lies at larger energies in the response function. The octupole modes give the dominant contribution, and the effect in average becomes smaller as the multipolarity increases. These results agree quite well with those obtained taking into account the zero point fluctuations of the nuclear surface in the collective model with the Esbensen and Bertsch prescription, which the authors use to explain the anomalous behaviour of the mean square radii of the Calcium isotopes
Random interactions, isospin, and the ground states of odd-A and odd-odd nuclei
International Nuclear Information System (INIS)
Horoi, Mihai; Volya, Alexander; Zelevinsky, Vladimir
2002-01-01
It was recently shown that the ground state quantum numbers of even-even nuclei have a high probability to be reproduced by an ensemble of random but rotationally invariant two-body interactions. In the present work we extend these investigations to odd-A and odd-odd nuclei, considering in particular the isospin effects. Studying the realistic shell model as well as the single-j model, we show that random interactions have a tendency to assign the lowest possible total angular momentum and isospin to the ground state. In the sd shell model this reproduces correctly the isospin but not the spin quantum numbers of actual odd-odd nuclei. An odd-even staggering effect in probability of various ground state quantum numbers is present for even-even and odd-odd nuclei, while it is smeared out for odd-A nuclei. The observed regularities suggest the underlying mechanism of bosonlike pairing of fermionic pairs in T=0 and T=1 states generated by the off-diagonal matrix elements of random interactions. The relation to the models of random spin interactions is briefly discussed
Normal ground state of dense relativistic matter in a magnetic field
International Nuclear Information System (INIS)
Gorbar, E. V.; Miransky, V. A.; Shovkovy, I. A.
2011-01-01
The properties of the ground state of relativistic matter in a magnetic field are examined within the framework of a Nambu-Jona-Lasinio model. The main emphasis of this study is the normal ground state, which is realized at sufficiently high temperatures and/or sufficiently large chemical potentials. In contrast to the vacuum state, which is characterized by the magnetic catalysis of chiral symmetry breaking, the normal state is accompanied by the dynamical generation of the chiral shift parameter Δ. In the chiral limit, the value of Δ determines a relative shift of the longitudinal momenta (along the direction of the magnetic field) in the dispersion relations of opposite chirality fermions. We argue that the chirality remains a good approximate quantum number even for massive fermions in the vicinity of the Fermi surface and, therefore, the chiral shift is expected to play an important role in many types of cold dense relativistic matter, relevant for applications in compact stars. The qualitative implications of the revealed structure of the normal ground state on the physics of protoneutron stars are discussed. A noticeable feature of the Δ parameter is that it is insensitive to temperature when T 0 , where μ 0 is the chemical potential, and increases with temperature for T>μ 0 . The latter implies that the chiral shift parameter is also generated in the regime relevant for heavy ion collisions.
Exact ground state of finite Bose-Einstein condensates on a ring
International Nuclear Information System (INIS)
Sakmann, Kaspar; Streltsov, Alexej I.; Alon, Ofir E.; Cederbaum, Lorenz S.
2005-01-01
The exact ground state of the many-body Schroedinger equation for N bosons on a one-dimensional ring interacting via a pairwise δ-function interaction is presented for up to 50 particles. The solutions are obtained by solving Lieb and Liniger's system of coupled transcendental equations numerically for finite N. The ground-state energies for repulsive and attractive interactions are shown to be smoothly connected at the point of zero interaction strength, implying that the Bethe ansatz can be used also for attractive interactions for all cases studied. For repulsive interactions the exact energies are compared to (i) Lieb and Liniger's thermodynamic limit solution and (ii) the Tonks-Girardeau gas limit. It is found that the energy of the thermodynamic limit solution can differ substantially from that of the exact solution for finite N when the interaction is weak or when N is small. A simple relation between the Tonks-Girardeau gas limit and the solution for finite interaction strength is revealed. For attractive interactions we find that the true ground-state energy is given to a good approximation by the energy of the system of N attractive bosons on an infinite line, provided the interaction is stronger than the critical interaction strength of mean-field theory
DEFF Research Database (Denmark)
Johnsen, Kristinn; Yngvason, Jakob
1996-01-01
We report on a numerical study of the density matrix functional introduced by Lieb, Solovej, and Yngvason for the investigation of heavy atoms in high magnetic fields. This functional describes exactly the quantum mechanical ground state of atoms and ions in the limit when the nuclear charge Z...... and the electron number N tend to infinity with N/Z fixed, and the magnetic field B tends to infinity in such a way that B/Z4/3→∞. We have calculated electronic density profiles and ground-state energies for values of the parameters that prevail on neutron star surfaces and compared them with results obtained...... by other methods. For iron at B=1012 G the ground-state energy differs by less than 2% from the Hartree-Fock value. We have also studied the maximal negative ionization of heavy atoms in this model at various field strengths. In contrast to Thomas-Fermi type theories atoms can bind excess negative charge...
Ground state properties of a spin chain within Heisenberg model with a single lacking spin site
International Nuclear Information System (INIS)
Mebrouki, M.
2011-01-01
The ground state and first excited state energies of an antiferromagnetic spin-1/2 chain with and without a single lacking spin site are computed using exact diagonalization method, within the Heisenberg model. In order to keep both parts of a spin chain with a lacking site connected, next nearest neighbors interactions are then introduced. Also, the Density Matrix Renormalization Group (DMRG) method is used, to investigate ground state energies of large system sizes; which permits us to inquire about the effect of large system sizes on energies. Other quantum quantities such as fidelity and correlation functions are also studied and compared in both cases. - Research highlights: → In this paper we compute ground state and first excited state energies of a spin chain with and without a lacking spin site. The next nearest neighbors are introduced with the antiferromagnetic Heisenberg spin-half. → Exact diagonalization is used for small systems, where DMRG method is used to compute energies for large systems. Other quantities like quantum fidelity and correlation are also computed. → Results are presented in figures with comments. → E 0 /N is computed in a function of N for several values of J 2 and for both systems. First excited energies are also investigated.
Emergent Ising degrees of freedom above a double-stripe magnetic ground state
Zhang, Guanghua; Flint, Rebecca
2017-12-01
Double-stripe magnetism [Q =(π /2 ,π /2 )] has been proposed as the magnetic ground state for both the iron-telluride and BaTi2Sb2O families of superconductors. Double-stripe order is captured within a J1-J2-J3 Heisenberg model in the regime J3≫J2≫J1 . Intriguingly, besides breaking spin-rotational symmetry, the ground-state manifold has three additional Ising degrees of freedom associated with bond ordering. Via their coupling to the lattice, they give rise to an orthorhombic distortion and to two nonuniform lattice distortions with wave vector (π ,π ) . Because the ground state is fourfold degenerate, modulo rotations in spin space, only two of these Ising bond order parameters are independent. Here, we introduce an effective field theory to treat all Ising order parameters, as well as magnetic order, and solve it within a large-N limit. All three transitions, corresponding to the condensations of two Ising bond order parameters and one magnetic order parameter are simultaneous and first order in three dimensions, but lower dimensionality, or equivalently weaker interlayer coupling, and weaker magnetoelastic coupling can split the three transitions, and in some cases allows for two separate Ising phase transitions above the magnetic one.
High spin polarization and the origin of unique ferromagnetic ground state in CuFeSb
International Nuclear Information System (INIS)
Sirohi, Anshu; Saha, Preetha; Gayen, Sirshendu; Gaurav, Abhishek; Jyotsna, Shubhra; Sheet, Goutam; Singh, Chandan K.; Kabir, Mukul; Thakur, Gohil S.; Haque, Zeba; Gupta, L. C.; Ganguli, Ashok K.
2016-01-01
CuFeSb is isostructural to the ferro-pnictide and chalcogenide superconductors and it is one of the few materials in the family that are known to stabilize in a ferromagnetic ground state. Majority of the members of this family are either superconductors or antiferromagnets. Therefore, CuFeSb may be used as an ideal source of spin polarized current in spin-transport devices involving pnictide and the chalcogenide superconductors. However, for that the Fermi surface of CuFeSb needs to be sufficiently spin polarized. In this paper we report direct measurement of transport spin polarization in CuFeSb by spin-resolved Andreev reflection spectroscopy. From a number of measurements using multiple superconducting tips we found that the intrinsic transport spin polarization in CuFeSb is high (∼47%). In order to understand the unique ground state of CuFeSb and the origin of large spin polarization at the Fermi level, we have evaluated the spin-polarized band structure of CuFeSb through first principles calculations. Apart from supporting the observed 47% transport spin polarization, such calculations also indicate that the Sb-Fe-Sb angles and the height of Sb from the Fe plane are strikingly different for CuFeSb than the equivalent parameters in other members of the same family thereby explaining the origin of the unique ground state of CuFeSb.
High spin polarization and the origin of unique ferromagnetic ground state in CuFeSb
Energy Technology Data Exchange (ETDEWEB)
Sirohi, Anshu; Saha, Preetha; Gayen, Sirshendu; Gaurav, Abhishek; Jyotsna, Shubhra; Sheet, Goutam, E-mail: goutam@iisermohali.ac.in [Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S. A. S. Nagar, Manauli PO 140306 (India); Singh, Chandan K.; Kabir, Mukul [Department of Physics, Indian Institute of Science Education and Research, Pune 411008 (India); Thakur, Gohil S.; Haque, Zeba; Gupta, L. C. [Department of Chemistry, Indian Institute of Technology, New Delhi 110016 (India); Ganguli, Ashok K. [Department of Chemistry, Indian Institute of Technology, New Delhi 110016 (India); Institute of Nano Science & Technology, Mohali 160064 (India)
2016-06-13
CuFeSb is isostructural to the ferro-pnictide and chalcogenide superconductors and it is one of the few materials in the family that are known to stabilize in a ferromagnetic ground state. Majority of the members of this family are either superconductors or antiferromagnets. Therefore, CuFeSb may be used as an ideal source of spin polarized current in spin-transport devices involving pnictide and the chalcogenide superconductors. However, for that the Fermi surface of CuFeSb needs to be sufficiently spin polarized. In this paper we report direct measurement of transport spin polarization in CuFeSb by spin-resolved Andreev reflection spectroscopy. From a number of measurements using multiple superconducting tips we found that the intrinsic transport spin polarization in CuFeSb is high (∼47%). In order to understand the unique ground state of CuFeSb and the origin of large spin polarization at the Fermi level, we have evaluated the spin-polarized band structure of CuFeSb through first principles calculations. Apart from supporting the observed 47% transport spin polarization, such calculations also indicate that the Sb-Fe-Sb angles and the height of Sb from the Fe plane are strikingly different for CuFeSb than the equivalent parameters in other members of the same family thereby explaining the origin of the unique ground state of CuFeSb.
Design of an electrostatic magnetic quadrupole accelerator
International Nuclear Information System (INIS)
Mizuno, M.; Ohara, Y.
1993-01-01
A new type of electrostatic acceleration system, electrostatic magnetic quadrupole (ESMQ) acceleration system, is proposed for efficient acceleration of negative ion beams. In this system, permanent magnets are buried in the acceleration electrodes so as to produce a quadrupole magnetic field in the electrode aperture region. Envelope simulation indicates that the quadrupole field can deflect electrons stripped from the negative ions. Beam envelope simulations for deuterium ions and electrons have been carried out using the beam envelope code TRACE. Electrons are largely divergent and most appear likely to hit downstream electrodes. Furthermore, maximum beam divergence of the deuterium ions is reduced to the focusing effect of the quadrupole magnetic field
International Nuclear Information System (INIS)
Clement, H.; Frick, R.; Graw, G.; Schiemenz, P.; Seichert, N.
1983-01-01
The 2 1 + -excitation of deformed nuclei by tensor polarized deuterons provides an alignment of both nuclei and thus a means to study specifically the quadrupole-quadrupole interaction between both nuclei. The tensor analyzing power Asub(xz)(theta) has been measured for the elastic and inelastic scattering on 24 Mg and 28 Si. The coupled channel analysis including a deformed tensor potential reveals a clear signature of the quadrupole-quadrupole part of the nuclear projectile-target interaction. (orig.)
Kvaal, Simen; Helgaker, Trygve
2015-11-14
The relationship between the densities of ground-state wave functions (i.e., the minimizers of the Rayleigh-Ritz variation principle) and the ground-state densities in density-functional theory (i.e., the minimizers of the Hohenberg-Kohn variation principle) is studied within the framework of convex conjugation, in a generic setting covering molecular systems, solid-state systems, and more. Having introduced admissible density functionals as functionals that produce the exact ground-state energy for a given external potential by minimizing over densities in the Hohenberg-Kohn variation principle, necessary and sufficient conditions on such functionals are established to ensure that the Rayleigh-Ritz ground-state densities and the Hohenberg-Kohn ground-state densities are identical. We apply the results to molecular systems in the Born-Oppenheimer approximation. For any given potential v ∈ L(3/2)(ℝ(3)) + L(∞)(ℝ(3)), we establish a one-to-one correspondence between the mixed ground-state densities of the Rayleigh-Ritz variation principle and the mixed ground-state densities of the Hohenberg-Kohn variation principle when the Lieb density-matrix constrained-search universal density functional is taken as the admissible functional. A similar one-to-one correspondence is established between the pure ground-state densities of the Rayleigh-Ritz variation principle and the pure ground-state densities obtained using the Hohenberg-Kohn variation principle with the Levy-Lieb pure-state constrained-search functional. In other words, all physical ground-state densities (pure or mixed) are recovered with these functionals and no false densities (i.e., minimizing densities that are not physical) exist. The importance of topology (i.e., choice of Banach space of densities and potentials) is emphasized and illustrated. The relevance of these results for current-density-functional theory is examined.
MQXFS1 Quadrupole Fabrication Report
Ambrosio, G; Bossert, R; Cavanna, E; Cheng, D; Chlachidize, G; Cooley, L D; Dietderich, D; Felice, H; Ferracin, P; Ghosh, A; Hafalia, R; Holik, E F; Izquierdo Bermudez, S; Juchno, M; Krave, S; Marchevsky, M; Muratore, J; Nobrega, F; Pan, H; Perez, J C; Pong, I; Prestemon, S; Ravaioli, E; Sabbi, G L; Santini, C; Schmalzle, J; Schmalzle, J; Stoynev, S; Strauss, T; Vallone, G; Wanderer, P; Wang, X; Yu, M
2017-01-01
This report presents the fabrication and QC data of MQXFS1, the first short model of the low-beta quadrupoles (MQXF) for the LHC High Luminosity Upgrade. It describes the conductor, the coils, and the structure that make the MQXFS1 magnet. Qualification tests and non-conformities are also presented and discussed. The fabrication of MQXFS1 was started before the finalization of conductor and coil design for MQXF magnets. Two strand design were used (RRP 108/127 and RRP 132/169). Cable and coil cross-sections were “first generation”.
MQXFS1 Quadrupole Fabrication Report
Energy Technology Data Exchange (ETDEWEB)
Ambrosio, G. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Anerella, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Bossert, R. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Cavanna, E. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Cheng, D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chlachidize, G. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Cooley, L. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Dietderich, D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Felice, H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ferracin, P. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Ghosh, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hafalia, R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Holik, E. F. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Bermudez, S. Izquierdo [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Juchno, M. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Krave, S. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Marchevsky, M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Muratore, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Nobrega, F. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Pan, H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Perez, J. C. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Pong, I. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Prestemon, S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ravaioli, E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sabbi, G. L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Santini, C. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Schmalzle, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Stoynev, S. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Strauss, T. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Vallone, G. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Wanderer, P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wang, X. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Yu, M. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
2017-07-16
This report presents the fabrication and QC data of MQXFS1, the first short model of the low-beta quadrupoles (MQXF) for the LHC High Luminosity Upgrade. It describes the conductor, the coils, and the structure that make the MQXFS1 magnet. Qualification tests and non-conformities are also presented and discussed. The fabrication of MQXFS1 was started before the finalization of conductor and coil design for MQXF magnets. Two strand design were used (RRP 108/127 and RRP 132/169). Cable and coil cross-sections were “first generation”.
Electric quadruple moments of high-spin isomers in 209Po
International Nuclear Information System (INIS)
Ivanov, E.A.; Nicolescu, G.; Plostinaru, D.
1998-01-01
The electric quadrupole interaction of the 209 Po (17/2) - and (13/2) - isomers in a Bi single-crystal was measured. The results for the quadrupole moments are connected with studies of isomers in Po isotopes. A two level analysis procedure was employed for the combined data of (17/2) - and (13/2) - isomers. The quadrupole moments of the Po isotopes are of special interest for testing nuclear models because of supposed simple nuclear structure with two protons outside a closed magic number shell. While the g-factors are significant for the predominant few-particle structures often present at high spins, the quadrupole moments are sensitive to additional contributions arising from core deformation effects. A systematic study of quadrupole moments of 12 + isomers in Pb isotopes has indeed demonstrated that the valence neutron effective charge increases as more particle pairs are removed from the 208 Pb core. In the present work, quadrupole coupling constants were measured for the isomers by the time-differential perturbed angular distribution (TDPAD) technique, in the presence of quadrupole interactions from the internal electric field gradient (EFG) in Bi crystal. The experiments were performed using a pulsed deuteron-beam of 13 MeV. The (17/2) - isomer state (T 1/2 = 88 ns) and the (13/2) - isomer state (T 1/2 = 24 ns) were populated and aligned by the 209 Bi(d,2n) reaction. The repetition time of the pulse was 10 μs and the width was around 5 ns (FWHM). The rather low bombardment energy was chosen to reduce population of higher spin isomers and to optimize the population of 209 Po((17/2) - ) and 209 Po((13/2) - ). The 209 Po single crystal target was held at a temperature of 470 K in order to reduce possible radiation damage effects. The experiments have been performed with the c axis of the single crystal at 45 angle and 90 angle to the beam direction. We chose to use a calibration based on isomers with well-understood nuclear structure allowing a reliable
Istomin, S Ya; Tyablikov, O A; Kazakov, S M; Antipov, E V; Kurbakov, A I; Tsirlin, A A; Hollmann, N; Chin, Y Y; Lin, H-J; Chen, C T; Tanaka, A; Tjeng, L H; Hu, Z
2015-06-21
The crystal and magnetic structures of brownmillerite-like Sr(2)Co(1.2)Ga(0.8)O(5) with a stable Co(3+) oxidation state at both octahedral and tetrahedral sites are refined using neutron powder diffraction data collected at 2 K (S.G. Icmm, a = 5.6148(6) Å, b = 15.702(2) Å, c = 5.4543(6) Å; R(wp) = 0.0339, R(p) = 0.0443, χ(2) = 0.775). The very large tetragonal distortion of CoO(6) octahedra (1.9591(4) Å for Co-O(eq) and 2.257(6) Å for Co-O(ax)) could be beneficial for the stabilization of the long-sought intermediate-spin state of Co(3+) in perovskite-type oxides. However, the large magnetic moment of octahedral Co(3+) (3.82(7)μ(B)) indicates the conventional high-spin state of Co(3+) ions, which is further supported by the results of a combined theoretical and experimental soft X-ray absorption spectroscopy study at the Co-L(2,3) edges on Sr(2)Co(1.2)Ga(0.8)O(5). A high-spin ground state of Co(3+) in Sr(2)Co(1.2)Ga(0.8)O(5) resulted in much lower in comparison with a LaCoO(3) linear thermal expansion coefficient of 13.1 ppm K(-1) (298-1073 K) determined from high-temperature X-ray powder diffraction data collected in air.
Simulation of a quadrupole resonator
Energy Technology Data Exchange (ETDEWEB)
Kleindienst, Raphael [Helmholtz Zentrum Berlin (Germany)
2013-07-01
Modern particle accelerators often rely on superconducting radio frequency (SRF) technology for accelerating cavities. In particular in CW operation, very high quality factors up into the high range are desirable, since one of the main cost drivers of such an accelerator, the cryogenic refrigeration plant, is inversely proportional to Q{sub 0}. Present day superconducting cavities are generally made of solid Niobium. A possibility to increase the quality factor as well as accelerating fields is to use thin film coated cavities. Apart from Niobium thin films, other superconducting materials, such as MgB{sub 2}, NbN and Nb{sub 3}Sn are promising candidates. Measuring and understanding the RF-properties of superconducting thin films, specifically the surface resistance, is needed to drive forward this development. Currently only few facilities exist capable of measuring the surface resistance of thin films samples with a resolution in the nano-ohm range at the operating frequency of typical cavities(e.g. L-band). A dedicated test stand consisting of a quadrupole resonator is therefore being constructed at the Helmholtz Zentrum Berlin. This system is based on the 400 MHz quadrupole resonator at CERN, with the design adapted to 433 MHz (making available the higher harmonic mode at 1.3 GHz) and optimized with respect to resolution and maximum achievable fields using simulation data obtained with CST Microwave Studio as well as ANSYS. The simulated design is being manufactured. An outlook for future physics runs is given.
International Nuclear Information System (INIS)
Lipkin, H.J.
1983-06-01
The new experimental values of hyperon magnetic moments are compared with sum rules predicted from general quark models. Three difficulties are encountered which are not easily explained by simple models. The isovector contributions of nonstrange quarks to hyperon moments are smaller than the corresponding contribution to nucleon moments, indicating either appreciable configuration mixing present in hyperon wave functions and absent in nucleons or an additional isovector contribution beyond that of valence quarks; e.g. from a pion cloud. The large magnitude of the ω - moment may indicate that the strange quark contribution to the ω moments is considerably larger than the value μ(#betta#) predicted by simple models which have otherwise been very successful. The set of controversial values from different experiments of the μ - moment include a value very close to -(1/2)μ(μ + ) which would indicate that strange quarks do not contribute at all to the μ moments. (author)
Electrostatic quadrupoles for heavy-ion fusion
International Nuclear Information System (INIS)
Seidl, P.; Faltens, A.
1993-05-01
Voltage-holding data for three quadrupole electrode sizes and inter-electrode spacings are reported. The dependence of the breakdown voltage on system size and its influence on the optimum quadrupole size for beam transport in a multiple beam array are discussed
A strong focussing cylindrical electrostatic quadrupole
International Nuclear Information System (INIS)
Sheng Yaochang
1986-01-01
The construction and performance of small cylindrical electrostatic quadrupole, which is installed in JM-400 pulse electrostatic accelerator, are described. This electrostatic quadrupole is not only used in neutron generator, but also suitable for ion injector as well as for low energy electron accelerator
Molecular multipole moments of water molecules in ice Ih
International Nuclear Information System (INIS)
Batista, E.R.; Xantheas, S.S.; Jonsson, H.
1998-01-01
We have used an induction model including dipole, dipole endash quadrupole, quadrupole endash quadrupole polarizability and first hyperpolarizability as well as fixed octopole and hexadecapole moments to study the electric field in ice. The self-consistent induction calculations gave an average total dipole moment of 3.09 D, a 67% increase over the dipole moment of an isolated water molecule. A previous, more approximate induction model study by Coulson and Eisenberg [Proc. R. Soc. Lond. A 291, 445 (1966)] suggested a significantly smaller average value of 2.6 D. This value has been used extensively in recent years as a reference point in the development of various polarizable interaction potentials for water as well as for assessment of the convergence of water cluster properties to those of bulk. The reason for this difference is not due to approximations made in the computational scheme of Coulson and Eisenberg but rather due to the use of less accurate values for the molecular multipoles in these earlier calculations. copyright 1998 American Institute of Physics
International Nuclear Information System (INIS)
Siddlingeshwar, B.; Hanagodimath, S.M.; Kirilova, E.M.; Kirilov, Georgii K.
2011-01-01
The effect of solvents on absorption and fluorescence spectra and dipole moments of novel benzanthrone derivatives such as 3-N-(N',N'-Dimethylformamidino) benzanthrone (1), 3-N-(N',N'-Diethylacetamidino) benzanthrone (2) and 3-morpholinobenzanthrone (3) have been studied in various solvents. The fluorescence lifetime of the dyes (1-3) in chloroform were also recorded. Bathochromic shift observed in the absorption and fluorescence spectra of these molecules with increasing solvent polarity indicates that the transitions involved are π→π * . Using the theory of solvatochromism, the difference in the excited-state (μ e ) and the ground-state (μ e ) dipole moments was estimated from Lippert-Mataga, Bakhshiev, Kawski-Chamma-Viallet, and McRae equations by using the variation of Stokes shift with the solvent's relative permittivity and refractive index. AM1 and PM6 semiempirical molecular calculations using MOPAC and ab-initio calculations at B3LYP/6-31 G * level of theory using Gaussian 03 software were carried out to estimate the ground-state dipole moments and some other physicochemical properties. Further, the change in dipole moment value (Δμ) was also calculated by using the variation of Stokes shift with the molecular-microscopic empirical solvent polarity parameter (E T N ). The excited-state dipole moments observed are larger than their ground-state counterparts, indicating a substantial redistribution of the π-electron densities in a more polar excited state for all the systems investigated.
Energy Technology Data Exchange (ETDEWEB)
Harrington, B J; Shepard, H K [New Hampshire Univ., Durham (USA). Dept. of Physics
1976-03-22
By fully exploiting the mathematical and physical analogy to the Ginzburg-Landau theory of superconductivity, a complete discussion of the ground state behavior of the four-dimensional Abelian Higgs model in the static tree level approximation is presented. It is shown that a sufficiently strong external magnetic field can alter the ground state of the theory by restoring a spontaneously broken symmetry, or by creating a qualitatively different 'vortex' state. The energetically favored ground state is explicitly determined as a function of the external field and the ratio between coupling constants of the theory.
International Nuclear Information System (INIS)
Yuan Qingxin; Ding Guohui
2005-01-01
We investigate the phenomena of symmetry breaking and phase transition in the ground state of Bose-Einstein condensates (BECs) trapped in a double square well and in an optical lattice well, respectively. By using standing-wave expansion method, we present symmetric and asymmetric ground state solutions of nonlinear Schroedinger equation (NLSE) with a symmetric double square well potential for attractive nonlinearity. In particular, we study the ground state wave function's properties by changing the depth of potential and atomic interactions (here we restrict ourselves to the attractive regime). By using the Fourier grid Hamiltonian method, we also reveal a phase transition of BECs trapped in one-dimensional optical lattice potential.
International Nuclear Information System (INIS)
Paraan, Francis N. C.; Korepin, Vladimir E.
2010-01-01
We calculate the first-order perturbation correction to the ground-state energy and chemical potential of a harmonically trapped boson gas with contact interactions about the infinite repulsion Tonks-Girardeau limit. With c denoting the interaction strength, we find that, for a large number of particles N, the 1/c correction to the ground-state energy increases as N 5/2 , in contrast to the unperturbed Tonks-Girardeau value that is proportional to N 2 . We describe a thermodynamic scaling limit for the trapping frequency that yields an extensive ground-state energy and reproduces the zero temperature thermodynamics obtained by a local-density approximation.
Gropengiesser, Uwe
1995-06-01
We compare various evlutionary strategies to determine the ground-state energy of the ± J spin glass. We show that the choice of different evolution laws is less important than a suitable treatment of the "free spins" of the system At least one combination of these strategies does not give the correct results, but the ground states of the other different strategies coincide. Therefore we are able to extrapolate the infinit-size ground-state energy for the square lattice to -1.401±0.0015 and for the simple cubic lattice to -1.786±0.004.
International Nuclear Information System (INIS)
Cirak, C.; Saglam, A.; Ucun, F.
2010-01-01
The ground state hydrogen conformations of 2-, 3-, 4- and 5-dihydroxybenzaldehyde have been investigated using density functional theory (B3LYP) methods with 6-31G (d,p) basis set. The calculations have indicated that the compounds in the ground state exist with the carbonyl group O atom linked intra molecularly by the two hydrogen bonds of the two hydroxyl groups. The vibrational analyses of the ground state conformers of all the compounds were done and their optimized geometry parameters were given.
Exact ground-state phase diagrams for the spin-3/2 Blume-Emery-Griffiths model
International Nuclear Information System (INIS)
Canko, Osman; Keskin, Mustafa; Deviren, Bayram
2008-01-01
We have calculated the exact ground-state phase diagrams of the spin-3/2 Ising model using the method that was proposed and applied to the spin-1 Ising model by Dublenych (2005 Phys. Rev. B 71 012411). The calculated, exact ground-state phase diagrams on the diatomic and triangular lattices with the nearest-neighbor (NN) interaction have been presented in this paper. We have obtained seven and 15 topologically different ground-state phase diagrams for J>0 and J 0 and J<0, respectively, the conditions for the existence of uniform and intermediate phases have also been found
Application of the random phase approximation to some atoms with ns2 ground state configurations
International Nuclear Information System (INIS)
Wright, L.A.
1975-01-01
Atomic bound state properties such as excitation energies and oscillator strengths were calculated by the Random Phase Approximation (RPA), also known as the Time Dependent Hartree-Fock Approximation (TDHFA). The RPA is equivalent to describing excited states as the creation of particle-hole pairs and the application to atoms is important for two reasons: the wide range of densities in an atom will cause the physical interpretation and mathematical approximations to be much different than with a uniform density system, such as an electron gas; this method could detect the existence of collective states in atoms similar to those responsible for the giant dipole resonances in nuclei. The method is shown to be superior to the H-F method in three basic ways: (1) The RPA contains explicit correlations between the excited and ground states. These are not included in the H-F theory. One can apply this method to large atoms since only these correlations are explicitly included. (2) The RPA calculates excitation energies directly without recourse to highly correlated ground state wavefunctions. This is in contrast to the method of configuration mixing which is known to have slow convergence properties. (3) Oscillator strengths and photoionization cross sections can be calculated by finding the eigenvectors corresponding excitation energy eigenvalues. The strength of the RPA is that the excitation energies and oscillator strengths, which are relative quantities, are calculated directly. The results for the oscillator strengths show an improvement of up to 45 percent over the H-F values and an improvement over the RPA done with Hartree wavefunctions by as much as 65 percent. The work was limited to atoms with an ns 2 ground state configuration. These atoms were He, Be, Mg and Ca
Structural instability and ground state of the U{sub 2}Mo compound
Energy Technology Data Exchange (ETDEWEB)
Losada, E.L., E-mail: losada@cab.cnea.gov.ar [SIM" 3, Centro Atómico Bariloche, Comisión Nacional de Energía Atómica (Argentina); Garcés, J.E. [Gerencia de Investigación y Aplicaciones Nucleares, Comisión Nacional de Energía Atómica (Argentina)
2015-11-15
This work reports on the structural instability at T = 0 °K of the U{sub 2}Mo compound in the C11{sub b} structure under the distortion related to the C{sub 66} elastic constant. The electronic properties of U{sub 2}Mo such as density of states (DOS), bands and Fermi surface (FS) are studied to understand the source of the instability. The C11{sub b} structure can be interpreted as formed by parallel linear chains along the z-directions each one composed of successive U–Mo–U blocks. Hybridization due to electronic interactions inside the U–Mo–U blocks is slightly modified under the D{sub 6} distortion. The change in distance between chains modifies the U–U interaction and produces a split of f-states. The distorted structure is stabilized by a decrease in energy of the hybridized states, mainly between d-Mo and f-U states, together with the f-band split. Consequently, an induced Peierls distortion is produced in U{sub 2}Mo due to the D{sub 6} distortion. It is important to note that the results of this work indicate that the structure of the ground state of the U{sub 2}Mo compound is not the assumed C11{sub b} structure. It is suggested for the ground state a structure with hexagonal symmetry (P6 #168), ∼0.1 mRy below the energy of the recently proposed Pmmn structure. - Highlights: • Structural instability of the C11b compound due to the D6 deformation. • Induced Peierls distortion due to the D6 deformation. • Distorted structure is stabilized by hybridization and split of f-Uranium state. • P6 (#168) suggested ground state for the U{sub 2}Mo compound.
Spin-polarized ground state and exact quantization at ν=5/2
Pan, Wei
2002-03-01
The nature of the even-denominator fractional quantum Hall effect at ν=5/2 remains elusive, in particular, its ground state spin-polarization. An earlier, so-called "hollow core" model arrived at a spin-unpolarized wave function. The more recent calculations based on a model of BCS-like pairing of composite fermions, however, suggest that its ground state is spin-polarized. In this talk, I will first review the earlier experiments and then present our recent experimental results showing evidence for a spin-polarized state at ν=5/2. Our ultra-low temperature experiments on a high quality sample established the fully developed FQHE state at ν=5/2 as well as at ν=7/3 and 8/3, manifested by a vanishing R_xx and exact quantization of the Hall plateau. The tilted field experiments showed that the added in-plane magnetic fields not only destroyed the FQHE at ν=5/2, as seen before, but also induced an electrical anisotropy, which is now interpreted as a phase transition from a paired, spin-polarized ν=5/2 state to a stripe phase, not unlike the ones at ν=9/2, 11/2, etc in the N > 1 higher Landau levels. Furthermore, in the experiments on the heterojunction insulated-gate field-effect transistors (HIGFET) at dilution refrigerator temperatures, a strong R_xx minimum and a concomitant developing Hall plateau were observed at ν=5/2 in a magnetic field as high as 12.6 Tesla. This and the subsequent density dependent studies of its energy gap largely rule out a spin-singlet state and point quite convincingly towards a spin-polarized ground state at ν=5/2.
Structural instability and ground state of the U_2Mo compound
International Nuclear Information System (INIS)
Losada, E.L.; Garcés, J.E.
2015-01-01
This work reports on the structural instability at T = 0 °K of the U_2Mo compound in the C11_b structure under the distortion related to the C_6_6 elastic constant. The electronic properties of U_2Mo such as density of states (DOS), bands and Fermi surface (FS) are studied to understand the source of the instability. The C11_b structure can be interpreted as formed by parallel linear chains along the z-directions each one composed of successive U–Mo–U blocks. Hybridization due to electronic interactions inside the U–Mo–U blocks is slightly modified under the D_6 distortion. The change in distance between chains modifies the U–U interaction and produces a split of f-states. The distorted structure is stabilized by a decrease in energy of the hybridized states, mainly between d-Mo and f-U states, together with the f-band split. Consequently, an induced Peierls distortion is produced in U_2Mo due to the D_6 distortion. It is important to note that the results of this work indicate that the structure of the ground state of the U_2Mo compound is not the assumed C11_b structure. It is suggested for the ground state a structure with hexagonal symmetry (P6 #168), ∼0.1 mRy below the energy of the recently proposed Pmmn structure. - Highlights: • Structural instability of the C11b compound due to the D6 deformation. • Induced Peierls distortion due to the D6 deformation. • Distorted structure is stabilized by hybridization and split of f-Uranium state. • P6 (#168) suggested ground state for the U_2Mo compound.
Isospin mixing in the ground state of sup 5 sup 2 Mn
Schuurmans, P; Phalet, T; Severijns, N; Vereecke, B; Versyck, S
2000-01-01
The presence of isospin mixing into the ground state of sup 5 sup 2 Mn was studied via anisotropic positron emission from nuclei. With this method the isospin forbidden Fermi-component in the Gamow-Teller dominated beta decay was determined. It is shown that sample purity and the control of positron scattering is of vital importance. Comparison between theory and experiment shows that shell model calculations of the isospin mixing probability deviate by a factor three to seven from experiment. For more recent Hartree-Fock-RPA based calculations the difference is over two orders of magnitude.
Ground state shape and crossing of near spherical and deformed bands in 182Hg
International Nuclear Information System (INIS)
Ma, W.C.; Ramayya, A.V.; Hamilton, J.H.; Robinson, S.J.; Barclay, M.E.; Zhao, K.; Cole, J.D.; Zganjar, E.F.; Spejewski, E.H.
1983-01-01
The energy levels of 182 Hg have been identified for the first time through comparison of in-beam studies of the reactions 156 154 Gd( 32 S,4n) 184 182 Hg. Levels up to 12 + in 182 Hg were established from γ-γ coincidence and singles measurement. The data establish that the ground state shape is near spherical, and that the ground band is crossed by a well deformed band at 4 + . In contrast to IBA model predictions that the deformed band will rise in energy in 182 Hg compared to 184 Hg, the energies of the deformed levels in 182 Hg continue to drop. 7 references
Directory of Open Access Journals (Sweden)
Zhigang Hu
2014-01-01
Full Text Available In this paper, we apply the method of the Nehari manifold to study the fractional differential equation (d/dt((1/2 0Dt-β(u′(t+(1/2 tDT-β(u′(t= f(t,u(t, a.e. t∈[0,T], and u0=uT=0, where 0Dt-β, tDT-β are the left and right Riemann-Liouville fractional integrals of order 0≤β<1, respectively. We prove the existence of a ground state solution of the boundary value problem.
Ran, Shi-Ju
2016-05-01
In this work, a simple and fundamental numeric scheme dubbed as ab initio optimization principle (AOP) is proposed for the ground states of translational invariant strongly correlated quantum lattice models. The idea is to transform a nondeterministic-polynomial-hard ground-state simulation with infinite degrees of freedom into a single optimization problem of a local function with finite number of physical and ancillary degrees of freedom. This work contributes mainly in the following aspects: (1) AOP provides a simple and efficient scheme to simulate the ground state by solving a local optimization problem. Its solution contains two kinds of boundary states, one of which play the role of the entanglement bath that mimics the interactions between a supercell and the infinite environment, and the other gives the ground state in a tensor network (TN) form. (2) In the sense of TN, a novel decomposition named as tensor ring decomposition (TRD) is proposed to implement AOP. Instead of following the contraction-truncation scheme used by many existing TN-based algorithms, TRD solves the contraction of a uniform TN in an opposite way by encoding the contraction in a set of self-consistent equations that automatically reconstruct the whole TN, making the simulation simple and unified; (3) AOP inherits and develops the ideas of different well-established methods, including the density matrix renormalization group (DMRG), infinite time-evolving block decimation (iTEBD), network contractor dynamics, density matrix embedding theory, etc., providing a unified perspective that is previously missing in this fields. (4) AOP as well as TRD give novel implications to existing TN-based algorithms: A modified iTEBD is suggested and the two-dimensional (2D) AOP is argued to be an intrinsic 2D extension of DMRG that is based on infinite projected entangled pair state. This paper is focused on one-dimensional quantum models to present AOP. The benchmark is given on a transverse Ising
Ground-state properties of trapped Bose-Fermi mixtures: Role of exchange correlation
International Nuclear Information System (INIS)
Albus, Alexander P.; Wilkens, Martin; Illuminati, Fabrizio
2003-01-01
We introduce density-functional theory for inhomogeneous Bose-Fermi mixtures, derive the associated Kohn-Sham equations, and determine the exchange-correlation energy in local-density approximation. We solve numerically the Kohn-Sham system, and determine the boson and fermion density distributions and the ground-state energy of a trapped, dilute mixture beyond mean-field approximation. The importance of the corrections due to exchange correlation is discussed by a comparison with current experiments; in particular, we investigate the effect of the repulsive potential-energy contribution due to exchange correlation on the stability of the mixture against collapse
Composite model approach to the 2He4 nucleus ground state
International Nuclear Information System (INIS)
Mehrotra, I.; Agarwal, B.K.
1986-12-01
Assuming that the nucleons are (πμ) composite systems the helium nucleus is compared to a molecule consisting of four hydrogen-like atoms where pions are like nuclei and muons are like electrons. Ground state energy of 2 He 4 nucleus has been estimated in the framework of valence-bond method. Good agreement with the experimental value can be obtained if it is assumed that μ + μ - coupling is 3% stronger than the μ ± μ ± coupling. (author). 11 refs, 1 tab
Existence of a ground state for the confined hydrogen atom in non-relativistic QED
International Nuclear Information System (INIS)
Amour, Laurent; Faupin, Jeremy
2008-01-01
We consider a system of a hydrogen atom interacting with the quantized electromagnetic field. Instead of fixing the nucleus, we assume that the system is confined by its center of mass. This model is used in theoretical physics to explain the Lamb-Dicke effect. After a brief review of the literature, we explain how to verify some properly chosen binding conditions which lead to the existence of a ground state for our model, and for all values of the fine-structure constant
Ground-state properties of a dilute homogeneous Bose gas of hard disks in two dimensions
International Nuclear Information System (INIS)
Mazzanti, F.; Polls, A.; Fabrocini, A.
2005-01-01
The energy and structure of a dilute hard-disks Bose gas are studied in the framework of a variational many-body approach based on a Jastrow correlated ground-state wave function. The asymptotic behaviors of the radial distribution function and the one-body density matrix are analyzed after solving the Euler equation obtained by a free minimization of the hypernetted chain energy functional. Our results show important deviations from those of the available low density expansions, already at gas parameter values x∼0.001. The condensate fraction in 2D is also computed and found generally lower than the 3D one at the same x
Highly twisted 1,2:8,9-dibenzozethrenes: Synthesis, ground state, and physical properties
Sun, Zhe; Zheng, Bin; Hu, Pan; Huang, Kuo-Wei; Wu, Jishan
2014-01-01
Two soluble and stable 1,2:8,9-dibenzozethrene derivatives (3a,b) are synthesized through a palladium-catalyzed cyclodimerization reaction. X-ray crystallographic analysis shows that these molecules are highly twisted owing to congestion at the cove region. Broken-symmetry DFT calculations predict that they have a singlet biradical ground state with a smaller biradical character and a large singlet-triplet energy gap; these predictions are supported by NMR and electronic absorption measurements. They have small energy gaps and exhibit farred/near-infrared absorption/emission and amphoteric redox behaviors.
The magnetic structure on the ground state of the equilateral triangular spin tube
International Nuclear Information System (INIS)
Matsui, Kazuki; Goto, Takayuki; Manaka, Hirotaka; Miura, Yoko
2016-01-01
The ground state of the frustrated equilateral triangular spin tube CsCrF_4 is still hidden behind a veil though NMR spectrum broaden into 2 T at low temperature. In order to investigate the spin structure in an ordered state by "1"9F-NMR, we have determined the anisotropic hyperfine coupling tensors for each three fluorine sites in the paramagnetic state. The measurement field was raised up to 10 T to achieve highest resolution. The preliminary analysis using the obtained hyperfine tensors has shown that the archetypal 120°-type structure in ab-plane does not accord with the NMR spectra of ordered state.
Quantifying confidence in density functional theory predictions of magnetic ground states
Houchins, Gregory; Viswanathan, Venkatasubramanian
2017-10-01
Density functional theory (DFT) simulations, at the generalized gradient approximation (GGA) level, are being routinely used for material discovery based on high-throughput descriptor-based searches. The success of descriptor-based material design relies on eliminating bad candidates and keeping good candidates for further investigation. While DFT has been widely successfully for the former, oftentimes good candidates are lost due to the uncertainty associated with the DFT-predicted material properties. Uncertainty associated with DFT predictions has gained prominence and has led to the development of exchange correlation functionals that have built-in error estimation capability. In this work, we demonstrate the use of built-in error estimation capabilities within the BEEF-vdW exchange correlation functional for quantifying the uncertainty associated with the magnetic ground state of solids. We demonstrate this approach by calculating the uncertainty estimate for the energy difference between the different magnetic states of solids and compare them against a range of GGA exchange correlation functionals as is done in many first-principles calculations of materials. We show that this estimate reasonably bounds the range of values obtained with the different GGA functionals. The estimate is determined as a postprocessing step and thus provides a computationally robust and systematic approach to estimating uncertainty associated with predictions of magnetic ground states. We define a confidence value (c-value) that incorporates all calculated magnetic states in order to quantify the concurrence of the prediction at the GGA level and argue that predictions of magnetic ground states from GGA level DFT is incomplete without an accompanying c-value. We demonstrate the utility of this method using a case study of Li-ion and Na-ion cathode materials and the c-value metric correctly identifies that GGA-level DFT will have low predictability for NaFePO4F . Further, there
Topological Invariants and Ground-State Wave functions of Topological Insulators on a Torus
Directory of Open Access Journals (Sweden)
Zhong Wang
2014-01-01
Full Text Available We define topological invariants in terms of the ground-state wave functions on a torus. This approach leads to precisely defined formulas for the Hall conductance in four dimensions and the topological magnetoelectric θ term in three dimensions, and their generalizations in higher dimensions. They are valid in the presence of arbitrary many-body interactions and disorder. These topological invariants systematically generalize the two-dimensional Niu-Thouless-Wu formula and will be useful in numerical calculations of disordered topological insulators and strongly correlated topological insulators, especially fractional topological insulators.
Optimized RVB states of the 2-d antiferromagnet: ground state and excitation spectrum
Chen, Yong-Cong; Xiu, Kai
1993-10-01
The Gutzwiller projection of the Schwinger-boson mean-field solution of the 2-d spin- {1}/{2} antiferromagnet in a square lattice is shown to produce the optimized, parameter-free RVB ground state. We get -0.6688 J/site and 0.311 for the energy and the staggered magnetization. The spectrum of the excited states is found to be linear and gapless near k≅0. Our calculation suggests, upon breaking of the rotational symmetry, ɛ k≅2JZ r1-γ 2k with Zr≅1.23.
Resonant Ion Pair Formation in Electron Collisions with Ground State Molecular Ions
International Nuclear Information System (INIS)
Zong, W.; Dunn, G.H.; Djuric, N.; Greene, C.H.; Neau, A.; Zong, W.; Larsson, M.; Al-Khalili, A.; Neau, A.; Derkatch, A.M.; Vikor, L.; Shi, W.; Rosen, S.; Le Padellec, A.; Danared, H.; Ugglas, M. af
1999-01-01
Resonant ion pair formation from collisions of electrons with ground state diatomic molecular ions has been observed and absolute cross sections measured. The cross section for HD + is characterized by an abrupt threshold at 1.9thinspthinspeV and 14 resolved peaks in the range of energies 0≤E≤14 eV . The dominant mechanism responsible for the structures appears to be resonant capture and stabilization, modified by two-channel quantum interference. Data on HF + show structure correlated with photoionization of HF and with dissociative recombination of electrons with this ion. copyright 1999 The American Physical Society
The ground state energy of a bound polaron in the presence of a magnetic field
Energy Technology Data Exchange (ETDEWEB)
Zorkani, I [International Centre for Theoretical Physics, Trieste (Italy); Belhissi, R [Faculte des Sciences Dhar Mahraz, Fes (Morocco). Dept. de Physique
1995-09-01
A theoretical calculation for the ground state energy of a bound polaron as a function of the magnetic field is presented. The theory is based on a variational approach using a trial wave function proposed by Devreese et al. in the absence of the magnetic field. It was shown that his function is adequate for all electron - phonon coupling {alpha} and all parameter {gamma}{sub 0} which is the ratio between the L.O. phonon energy and the Colombian one. Analytical results are obtained in the weak coupling limit. (author). 27 refs, 4 figs, 1 tab.
Positive ground state solutions to Schrodinger-Poisson systems with a negative non-local term
Directory of Open Access Journals (Sweden)
Yan-Ping Gao
2015-04-01
Full Text Available In this article, we study the Schrodinger-Poisson system $$\\displaylines{ -\\Delta u+u-\\lambda K(x\\phi(xu=a(x|u|^{p-1}u, \\quad x\\in\\mathbb{R}^3, \\cr -\\Delta\\phi=K(xu^{2},\\quad x\\in\\mathbb{R}^3, }$$ with $p\\in(1,5$. Assume that $a:\\mathbb{R}^3\\to \\mathbb{R^{+}}$ and $K:\\mathbb{R}^3\\to \\mathbb{R^{+}}$ are nonnegative functions and satisfy suitable assumptions, but not requiring any symmetry property on them, we prove the existence of a positive ground state solution resolved by the variational methods.
Fahrenbach, Albert C; Bruns, Carson J; Cao, Dennis; Stoddart, J Fraser
2012-09-18
Fashioned through billions of years of evolution, biological molecular machines, such as ATP synthase, myosin, and kinesin, use the intricate relative motions of their components to drive some of life's most essential processes. Having control over the motions in molecules is imperative for life to function, and many chemists have designed, synthesized, and investigated artificial molecular systems that also express controllable motions within molecules. Using bistable mechanically interlocked molecules (MIMs), based on donor-acceptor recognition motifs, we have sought to imitate the sophisticated nanoscale machines present in living systems. In this Account, we analyze the thermodynamic characteristics of a series of redox-switchable [2]rotaxanes and [2]catenanes. Control and understanding of the relative intramolecular movements of components in MIMs have been vital in the development of a variety of applications of these compounds ranging from molecular electronic devices to drug delivery systems. These bistable donor-acceptor MIMs undergo redox-activated switching between two isomeric states. Under ambient conditions, the dominant translational isomer, the ground-state coconformation (GSCC), is in equilibrium with the less favored translational isomer, the metastable-state coconformation (MSCC). By manipulating the redox state of the recognition site associated with the GSCC, we can stimulate the relative movements of the components in these bistable MIMs. The thermodynamic parameters of model host-guest complexes provide a good starting point to rationalize the ratio of GSCC to MSCC at equilibrium. The bistable [2]rotaxanes show a strong correlation between the relative free energies of model complexes and the ground-state distribution constants (K(GS)). This relationship does not always hold for bistable [2]catenanes, most likely because of the additional steric and electronic constraints present when the two rings are mechanically interlocked with each other
Frequency dependent polarizabilities for the ground state of H2, HD, and D2
International Nuclear Information System (INIS)
Rychlewski, J.
1983-01-01
A variation-perturbation method has been employed to calculate the dynamic dipole polarizability for the ground state of the hydrogen molecule. The explicit correlated electronic wave functions were used. The averaged values of α(#betta#) and #betta#(#betta#) for several vibration-rotation states of HD and D 2 are presented. Similar values for H 2 have also been calculated and were used to test the efficiency of the method and the validity of the assumption applied in the present calculation. The agreement of the present theoretical results with the existing experimental data is found to be satisfactory
Simulations of ground state fluctuations in mean-field Ising spin glasses
International Nuclear Information System (INIS)
Boettcher, Stefan
2010-01-01
The scaling of fluctuations in the distribution of ground state energies or costs with the system size N for Ising spin glasses is considered using an extensive set of simulations with the extremal optimization heuristic across a range of different models on sparse and dense graphs. These models exhibit very diverse behaviors, and an asymptotic extrapolation is often complicated by higher-order corrections in size. The clearest picture, in fact, emerges from the study of graph bipartitioning, a combinatorial optimization problem closely related to spin glasses. Asides from two-spin interactions with discrete bonds, we also consider problems with Gaussian bonds and three-spin interactions, which behave quite differently
Ground state solutions for Choquard type equations with a singular potential
Directory of Open Access Journals (Sweden)
Tao Wang
2017-02-01
Full Text Available This article concerns the Choquard type equation $$ -\\Delta u+V(xu=\\Big(\\int_{\\mathbb{R}^N}\\frac{|u(y|^p}{|x-y|^{N-\\alpha}}dy\\Big |u|^{p-2}u,\\quad x\\in \\mathbb{R}^N, $$ where $N\\geq3$, $\\alpha\\in ((N-4_+,N$, $2\\leq p <(N+\\alpha/(N-2$ and V(x is a possibly singular potential and may be unbounded below. Applying a variant of the Lions' concentration-compactness principle, we prove the existence of ground state solution of the above equations.
Highly twisted 1,2:8,9-dibenzozethrenes: Synthesis, ground state, and physical properties
Sun, Zhe
2014-08-08
Two soluble and stable 1,2:8,9-dibenzozethrene derivatives (3a,b) are synthesized through a palladium-catalyzed cyclodimerization reaction. X-ray crystallographic analysis shows that these molecules are highly twisted owing to congestion at the cove region. Broken-symmetry DFT calculations predict that they have a singlet biradical ground state with a smaller biradical character and a large singlet-triplet energy gap; these predictions are supported by NMR and electronic absorption measurements. They have small energy gaps and exhibit farred/near-infrared absorption/emission and amphoteric redox behaviors.
Ground-state candidate for the classical dipolar kagome Ising antiferromagnet
Chioar, I. A.; Rougemaille, N.; Canals, B.
2016-06-01
We have investigated the low-temperature thermodynamic properties of the classical dipolar kagome Ising antiferromagnet using Monte Carlo simulations, in the quest for the ground-state manifold. In spite of the limitations of a single-spin-flip approach, we managed to identify certain ordering patterns in the low-temperature regime and we propose a candidate for this unknown state. This configuration presents some intriguing features and is fully compatible with the extrapolations of the at-equilibrium thermodynamic behavior sampled so far, making it a very likely choice for the dipolar long-range ordered state of the classical kagome Ising antiferromagnet.
An algebraic description of identical bands and of high-spin quadrupole collectivity
International Nuclear Information System (INIS)
Guidry, M.W.
1993-01-01
The Fermion Dynamical Symmetry Model (FDSM) has been used to describe electric quadrupole transition rates and static moments at high angular momentum in deformed nuclei. A quantitative description of these phenomena appears possible by these means. The formalism accounts naturally for those cases where significant reductions in B(E2) values are accompanied by relatively constant moments of inertia. A discussion of identical bands as being due to a dynamical symmetry will be given. The empirical properties of these bands and general principles of group theory will be used to place constraints on an acceptable symmetry. A model that represents a minimal implementation of these criteria will be presented
Quadrupole interaction in zinc metal
International Nuclear Information System (INIS)
Vetterling, W.T.; Pound, R.V.
1977-01-01
To allow measurement of the quadrupole interaction in zinc metal, the enriched ZnO was reduced to zinc metal powder and compressed into a pill of thickness 1.4 gm/cm 2 . Sources were made by diffusing 20 mCi of 67 Ga into sintered copper pills. The transducer was based on a cylinder of PZT-4 with 1 / 2 -inch length and could cover linearly a velocity range of +-100 μ/s at 200 Hz. The multiscalar was a modified Northern model NS600, with a minimum dwell time of 20 μs, and with a 10-count buffer at the input to eliminate deadtime from memory cycling
Exact ground-state phase diagrams for the spin-3/2 Blume-Emery-Griffiths model
Energy Technology Data Exchange (ETDEWEB)
Canko, Osman; Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Deviren, Bayram [Institute of Science, Erciyes University, 38039 Kayseri (Turkey)], E-mail: keskin@erciyes.edu.tr
2008-05-15
We have calculated the exact ground-state phase diagrams of the spin-3/2 Ising model using the method that was proposed and applied to the spin-1 Ising model by Dublenych (2005 Phys. Rev. B 71 012411). The calculated, exact ground-state phase diagrams on the diatomic and triangular lattices with the nearest-neighbor (NN) interaction have been presented in this paper. We have obtained seven and 15 topologically different ground-state phase diagrams for J>0 and J<0, respectively, on the diatomic lattice and have found the conditions for the existence of uniform and intermediate or non-uniform phases. We have also constructed the exact ground-state phase diagrams of the model on the triangular lattice and found 20 and 59 fundamental phase diagrams for J>0 and J<0, respectively, the conditions for the existence of uniform and intermediate phases have also been found.
Accurate Ground-State Energies of Solids and Molecules from Time-Dependent Density-Functional Theory
DEFF Research Database (Denmark)
Olsen, Thomas; Thygesen, Kristian Sommer
2014-01-01
We demonstrate that ground-state energies approaching chemical accuracy can be obtained by combining the adiabatic-connection fluctuation-dissipation theorem with time-dependent densityfunctional theory. The key ingredient is a renormalization scheme, which eliminates the divergence...
CSIR Research Space (South Africa)
de Clercq, L
2010-09-01
Full Text Available Coherent control of the upper vibrational level populations in the electronic ground state of a polyatomic molecule was simulated. Results indicate that selective excitation of a specific upper state level is possible...
International Nuclear Information System (INIS)
Liu Jia; Xiao Jingling
2006-01-01
We study theoretically the ground state energy of a polaron near the interface of a polar-polar semiconductor by considering the Rashba spin-orbit (SO) coupling with the Lee-Low-Pines intermediate coupling method. Our numerical results show that the Rashba SO interaction originating from the inversion asymmetry in the heterostructure splits the ground state energy of the polaron. The electron areal density and vector dependence of the ratio of the SO interaction to the total ground state energy or other energy composition are obvious. One can see that even without any external magnetic field, the ground state energy can be split by the Rashba SO interaction, and this split is not a single but a complex one. Since the presents of the phonons, whose energy gives negative contribution to the polaron's, the spin-splitting states of the polaron are more stable than electron's.
Marciano, William J
2010-01-01
This book provides a self-contained description of the measurements of the magnetic dipole moments of the electron and muon, along with a discussion of the measurements of the fine structure constant, and the theory associated with magnetic and electric dipole moments. Also included are the searches for a permanent electric dipole moment of the electron, muon, neutron and atomic nuclei. The related topic of the transition moment for lepton flavor violating processes, such as neutrinoless muon or tauon decays, and the search for such processes are included as well. The papers, written by many o
Rich Ground State Chemical Ordering in Nanoparticles: Exact Solution of a Model for Ag-Au Clusters
DEFF Research Database (Denmark)
Larsen, Peter Mahler; Jacobsen, Karsten Wedel; Schiøtz, Jakob
2018-01-01
We show that nanoparticles can have very rich ground state chemical order. This is illustrated by determining the chemical ordering of Ag-Au 309-atom Mackay icosahedral nanoparticles. The energy of the nanoparticles is described using a cluster expansion model, and a Mixed Integer Programming (MIP......) approach is used to find the exact ground state configurations for all stoichiometries. The chemical ordering varies widely between the different stoichiometries, and display a rich zoo of structures with non-trivial ordering....
High Fidelity Preparation of a Single Atom in Its 2D Center of Mass Ground State
Sompet, Pimonpan; Fung, Yin Hsien; Schwartz, Eyal; Hunter, Matthew D. J.; Phrompao, Jindaratsamee; Andersen, Mikkel F.
2017-04-01
Complete control over quantum states of individual atoms is important for the study of the microscopic world. Here, we present a push button method for high fidelity preparation of a single 85Rb atom in the vibrational ground state of tightly focused optical tweezers. The method combines near-deterministic preparation of a single atom with magnetically-insensitive Raman sideband cooling. We achieve 2D cooling in the radial plane with a ground state population of 0.85, which provides a fidelity of 0.7 for the entire procedure (loading and cooling). The Raman beams couple two sublevels (| F = 3 , m = 0 〉 and | F = 2 , m = 0 〉) that are indifferent to magnetic noise to first order. This leads to long atomic coherence times, and allows us to implement the cooling in an environment where magnetic field fluctuations prohibit previously demonstrated variations. Additionally, we implement the trapping and manipulation of two atoms confined in separate dynamically reconfigurable optical tweezers, to study few-body dynamics.
Gozem, Samer; Huntress, Mark; Schapiro, Igor; Lindh, Roland; Granovsky, Alexander A; Angeli, Celestino; Olivucci, Massimo
2012-11-13
The ground state potential energy surface of the retinal chromophore of visual pigments (e.g., bovine rhodopsin) features a low-lying conical intersection surrounded by regions with variable charge-transfer and diradical electronic structures. This implies that dynamic electron correlation may have a large effect on the shape of the force fields driving its reactivity. To investigate this effect, we focus on mapping the potential energy for three paths located along the ground state CASSCF potential energy surface of the penta-2,4-dieniminium cation taken as a minimal model of the retinal chromophore. The first path spans the bond length alternation coordinate and intercepts a conical intersection point. The other two are minimum energy paths along two distinct but kinetically competitive thermal isomerization coordinates. We show that the effect of introducing the missing dynamic electron correlation variationally (with MRCISD) and perturbatively (with the CASPT2, NEVPT2, and XMCQDPT2 methods) leads, invariably, to a stabilization of the regions with charge transfer character and to a significant reshaping of the reference CASSCF potential energy surface and suggesting a change in the dominating isomerization mechanism. The possible impact of such a correction on the photoisomerization of the retinal chromophore is discussed.
Ground-state and dynamical properties of two-dimensional dipolar Fermi liquids
International Nuclear Information System (INIS)
Abedinpour, Saeed H.; Asgari, Reza; Tanatar, B.; Polini, Marco
2014-01-01
We study the ground-state properties of a two-dimensional spin-polarized fluid of dipolar fermions within the Euler–Lagrange Fermi-hypernetted-chain approximation. Our method is based on the solution of a scattering Schrödinger equation for the “pair amplitude” √(g(r)), where g(r) is the pair distribution function. A key ingredient in our theory is the effective pair potential, which includes a bosonic term from Jastrow–Feenberg correlations and a fermionic contribution from kinetic energy and exchange, which is tailored to reproduce the Hartree–Fock limit at weak coupling. Very good agreement with recent results based on quantum Monte Carlo simulations is achieved over a wide range of coupling constants up to the liquid-to-crystal quantum phase transition. Using the fluctuation–dissipation theorem and a static approximation for the effective inter-particle interactions, we calculate the dynamical density–density response function, and furthermore demonstrate that an undamped zero-sound mode exists for any value of the interaction strength, down to infinitesimally weak couplings. -- Highlights: •We have studied the ground state properties of a strongly correlated two-dimensional fluid of dipolar fermions. •We have calculated the effective inter-particle interaction and the dynamical density–density response function. •We have shown that an undamped zero sound mode exists at any value of the interaction strength
The use of quadratic forms in the calculation of ground state electronic structures
International Nuclear Information System (INIS)
Keller, Jaime; Weinberger, Peter
2006-01-01
There are many examples in theoretical physics where a fundamental quantity can be considered a quadratic form ρ=Σ i ρ i =vertical bar Ψ vertical bar 2 and the corresponding linear form Ψ=Σ i ψ i is highly relevant for the physical problem under study. This, in particular, is the case of the density and the wave function in quantum mechanics. In the study of N-identical-fermion systems we have the additional feature that Ψ is a function of the 3N configuration space coordinates and ρ is defined in three-dimensional real space. For many-electron systems in the ground state the wave function and the Hamiltonian are to be expressed in terms of the configuration space (CS), a replica of real space for each electron. Here we present a geometric formulation of the CS, of the wave function, of the density, and of the Hamiltonian to compute the electronic structure of the system. Then, using the new geometric notation and the indistinguishability and equivalence of the electrons, we obtain an alternative computational method for the ground state of the system. We present the method and discuss its usefulness and relation to other approaches
Hartree–Fock many-body perturbation theory for nuclear ground-states
Directory of Open Access Journals (Sweden)
Alexander Tichai
2016-05-01
Full Text Available We investigate the order-by-order convergence behavior of many-body perturbation theory (MBPT as a simple and efficient tool to approximate the ground-state energy of closed-shell nuclei. To address the convergence properties directly, we explore perturbative corrections up to 30th order and highlight the role of the partitioning for convergence. The use of a simple Hartree–Fock solution for the unperturbed basis leads to a convergent MBPT series for soft interactions, in contrast to the divergent MBPT series obtained with a harmonic oscillator basis. For larger model spaces and heavier nuclei, where a direct high-order MBPT calculation is not feasible, we perform third-order calculations and compare to advanced ab initio coupled-cluster results for the same interactions and model spaces. We demonstrate that third-order MBPT provides ground-state energies for nuclei up into the tin isotopic chain in excellent agreement with the best available coupled-cluster calculations at a fraction of the computational cost.
Hartree–Fock many-body perturbation theory for nuclear ground-states
Energy Technology Data Exchange (ETDEWEB)
Tichai, Alexander, E-mail: alexander.tichai@physik.tu-darmstadt.de [Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt (Germany); Langhammer, Joachim [Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt (Germany); Binder, Sven [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Roth, Robert, E-mail: robert.roth@physik.tu-darmstadt.de [Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt (Germany)
2016-05-10
We investigate the order-by-order convergence behavior of many-body perturbation theory (MBPT) as a simple and efficient tool to approximate the ground-state energy of closed-shell nuclei. To address the convergence properties directly, we explore perturbative corrections up to 30th order and highlight the role of the partitioning for convergence. The use of a simple Hartree–Fock solution for the unperturbed basis leads to a convergent MBPT series for soft interactions, in contrast to the divergent MBPT series obtained with a harmonic oscillator basis. For larger model spaces and heavier nuclei, where a direct high-order MBPT calculation is not feasible, we perform third-order calculations and compare to advanced ab initio coupled-cluster results for the same interactions and model spaces. We demonstrate that third-order MBPT provides ground-state energies for nuclei up into the tin isotopic chain in excellent agreement with the best available coupled-cluster calculations at a fraction of the computational cost.
Electron pumping of the ground state of 21Ne. Transfers and multiple diffusion processes
International Nuclear Information System (INIS)
Stoeckel, F.; Lombardi, M.
1978-01-01
The electron-pumping process of the ground state of 21 Ne has been studied. It is demonstrated how in a neon cell at a pressure of 10 -4 to 10 -2 torr, a high frequency discharge can create a nuclear spin alignment in the fundamental level (I=3/2) when the excited levels are themselves aligned. The nuclear alignment is observed by monitoring the change of the linear polarization of several optical transitions during the magnetic resonance of the fundamental level. Various transfers of the alignments are investigated and a detailed study of the influence of the multiple diffusion is carried out. The multiple diffusion produces a depolarization and a relaxation of the nuclear spin. A theoretical calculation has been made for a two-level system with a J=1 radiative level and a J=0 ground state. Experimentally a relaxation time of the nuclear alignment varying from 37 ms to 240 ms is observed when the neon pressure decreases from 10 -2 to 10 -4 torr [fr
Ground-state energy of the interacting Bose gas in two dimensions: An explicit construction
International Nuclear Information System (INIS)
Beane, Silas R.
2010-01-01
The isotropic scattering phase shift is calculated for nonrelativistic bosons interacting at low energies via an arbitrary finite-range potential in d space-time dimensions. Scattering on a (d-1)-dimensional torus is then considered, and the eigenvalue equation relating the energy levels on the torus to the scattering phase shift is derived. With this technology in hand, and focusing on the case of two spatial dimensions, a perturbative expansion is developed for the ground-state energy of N identical bosons which interact via an arbitrary finite-range potential in a finite area. The leading nonuniversal effects due to range corrections and three-body forces are included. It is then shown that the thermodynamic limit of the ground-state energy in a finite area can be taken in closed form to obtain the energy per particle in the low-density expansion by explicitly summing the parts of the finite-area energy that diverge with powers of N. The leading and subleading finite-size corrections to the thermodynamic limit equation of state are also computed. Closed-form results--some well known, others perhaps not--for two-dimensional lattice sums are included in an Appendix.
The magnetic ground state and relationship to Kitaev physics in α-RuCl3
Banerjee, Arnab
The 2D Kitaev candidate alpha-RuCl3 consists of stacked honeycomb layers weakly coupled by Van der Waals interactions. Here we report the measurements of bulk properties and neutron diffraction in both powder and single crystal samples. Our results show that the full three dimensional magnetic ground state is highly pliable with at least two dominant phases corresponding to two different out-of-plane magnetic orders. They have different Neel temperatures dependent on the stacking of the 2D layers, such as a broad magnetic transition at TN = 14 K as observed in phase-pure powder samples, or a sharp magnetic transition at a lower TN = 7 K as observed in homogeneous single crystals with no evidence for stacking faults. The magnetic refinements of the neutron scattering data will be discussed, which in all cases shows the in-plane magnetic ground state is the zigzag phase common in Kitaev related materials including the honeycomb lattice Iridates. Inelastic neutron scattering in all cases shows that this material consistently exhibit strong two-dimensional magnetic fluctuations leading to a break-down of the classical spin-wave picture. Work performed at ORNL is supported by U.S. Dept. of Energy, Office of Basic Energy Sciences and Office of User Facilities Division.
Structure and magnetic ground states of spin-orbit coupled compound alpha-RuCl3
Banerjee, Arnab; Bridges, Craig; Yan, Jiaqiang; Mandrus, David; Stone, Matthew; Aczel, Adam; Li, Ling; Yiu, Yuen; Lumsden, Mark; Chakoumakos, Bryan; Tennant, Alan; Nagler, Stephen
2015-03-01
The layered material alpha-RuCl3 is composed of stacks of weakly coupled honeycomb lattices of octahedrally coordinated Ru3 + ions. The Ru ion ground state has 5 d electrons in the low spin state, with spin-orbit coupling very strong compared to other terms in the single ion Hamiltonian. The material is therefore an excellent candidate for investigating possible Heisenberg-Kitaev physics. In addition, this compound is very amenable to investigation by neutron scattering to explore the magnetic ground state and excitations in detail. In this talk, we discuss the synthesis of phase-pure alpha-RuCl3 and the characterization of the magnetization, susceptibility, and heat-capacity. We also report neutron diffraction on both powder and single crystal alpha-RuCl3, identifying the low temperature magnetic order observed in the material. The results, when compared to theoretical calculations, shed light on the relative importance of Kitaev and Heisenberg terms in the Hamiltonian. The research is supported by the DOE BES Scientific User Facility Division.
Energy Technology Data Exchange (ETDEWEB)
Gumberidze, A.; Stoehlker, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)]|[Frankfurt Univ. (Germany). Inst. fuer Kernphysik; Banas, D. [Pedagogical Univ., Kielce (PL). Inst. of Phys.] [and others
2005-05-01
X-ray spectra following radiative recombination of free electrons with bare uranium ions (U{sup 92+}) were measured at the electron cooler of the ESR storage ring. The most intense lines observed in the spectra can be attributed to the characteristic Lyman ground-state transitions and to the recombination of free electrons into the K-shell of the ions. Our experiment was carried out by utilizing the deceleration technique which leads to a considerable reduction of the uncertainties associated with Doppler corrections. This, in combination with the 0 observation geometry, allowed us to determine the ground-state Lamb shift in hydrogen-like uranium (U{sup 91+}) from the observed X-ray lines with an accuracy of 1%. The present result is about 3 times more precise than the most accurate value available up to now and provides the most stringent test of bound-state quantum electrodynamics for one-electron systems in the strong-field regime. (orig.)
International Nuclear Information System (INIS)
Morini, Filippo; Deleuze, Michael Simon; Watanabe, Noboru; Kojima, Masataka; Takahashi, Masahiko
2015-01-01
The influence of nuclear dynamics in the electronic ground state on the (e,2e) momentum profiles of dimethyl ether has been analyzed using the harmonic analytical quantum mechanical and Born-Oppenheimer molecular dynamics approaches. In spite of fundamental methodological differences, results obtained with both approaches consistently demonstrate that molecular vibrations in the electronic ground state have a most appreciable influence on the momentum profiles associated to the 2b 1 , 6a 1 , 4b 2 , and 1a 2 orbitals. Taking this influence into account considerably improves the agreement between theoretical and newly obtained experimental momentum profiles, with improved statistical accuracy. Both approaches point out in particular the most appreciable role which is played by a few specific molecular vibrations of A 1 , B 1 , and B 2 symmetries, which correspond to C–H stretching and H–C–H bending modes. In line with the Herzberg-Teller principle, the influence of these molecular vibrations on the computed momentum profiles can be unraveled from considerations on the symmetry characteristics of orbitals and their energy spacing
Skyrme's interaction beyond the mean-field. The DGCM+GOA Hamiltonian of nuclear quadrupole motion
International Nuclear Information System (INIS)
Kluepfel, Peter
2008-01-01
This work focuses on the microscopic description of nuclear collective quadrupole motion within the framework of the dynamic Generator-Coordinate-Method(DGCM)+Gaussian-Overlap-Approximation(GOA). Skyrme-type effective interactions are used as the fundamental many-particle interaction. Starting from a rotational invariant, polynomial and topologic consistent formulation of the GCM+GOA Hamiltonian an interpolation scheme for the collective masses and potential is developed. It allows to define the collective Hamiltonian of fully triaxial collective quadrupole dynamics from a purely axial symmetric configuration space. The substantial gain in performance allows the self-consistent evaluation of the dynamic quadrupole mass within the ATDHF-cranking model. This work presents the first large-scale analysis of quadrupole correlation energies and lowlying collective states within the DGCM+GOA model. Different Skyrme- and pairing interactions are compared from old standards up to more recent parameterizations. After checking the validity of several approximations to the DGCM+GOA model - both on the mean-field and the collective level - we proceed with a detailed investigation of correlation effects along the chains of semi-magic isotopes and isotones. This finally allows to define a set of observables which are hardly affected by collective correlations. Those observables were used for a refit of a Skyrme-type effective interaction which is expected to cure most of the problems of the recent parameterizations. Preparing further work, estimates for the correlated ground state energy are proposed which can be evaluated directly from the mean-field model. (orig.)
Skyrme's interaction beyond the mean-field. The DGCM+GOA Hamiltonian of nuclear quadrupole motion
Energy Technology Data Exchange (ETDEWEB)
Kluepfel, Peter
2008-07-29
This work focuses on the microscopic description of nuclear collective quadrupole motion within the framework of the dynamic Generator-Coordinate-Method(DGCM)+Gaussian-Overlap-Approximation(GOA). Skyrme-type effective interactions are used as the fundamental many-particle interaction. Starting from a rotational invariant, polynomial and topologic consistent formulation of the GCM+GOA Hamiltonian an interpolation scheme for the collective masses and potential is developed. It allows to define the collective Hamiltonian of fully triaxial collective quadrupole dynamics from a purely axial symmetric configuration space. The substantial gain in performance allows the self-consistent evaluation of the dynamic quadrupole mass within the ATDHF-cranking model. This work presents the first large-scale analysis of quadrupole correlation energies and lowlying collective states within the DGCM+GOA model. Different Skyrme- and pairing interactions are compared from old standards up to more recent parameterizations. After checking the validity of several approximations to the DGCM+GOA model - both on the mean-field and the collective level - we proceed with a detailed investigation of correlation effects along the chains of semi-magic isotopes and isotones. This finally allows to define a set of observables which are hardly affected by collective correlations. Those observables were used for a refit of a Skyrme-type effective interaction which is expected to cure most of the problems of the recent parameterizations. Preparing further work, estimates for the correlated ground state energy are proposed which can be evaluated directly from the mean-field model. (orig.)
Effect on the variation of the moment of inertia in band K=1/2
International Nuclear Information System (INIS)
Liu Yanxin; Yu Shaoying; Inner Mongolia Univ. for Nationalities, Tongliao; Chinese Academy of Sciences, Beijing
2004-01-01
The effect on the variation of the moment of inertia in band 171 Yb[521]1/2 is investigated using the particle number conserving (PNC) method for treating the cranked shell model with monopole and Y 20 quadrupole pairing interactions. The experimental moments of inertia of 171 Yb[521]1/2 (signature α=±1/2) and the blocking effect of proton are reproduced well by the PNC calculation, in which no free parameter is involved. (authors)
On the multipole moments of charge distributions
International Nuclear Information System (INIS)
Khare, P.L.
1977-01-01
There are two different standard methods for showing the equivalence of a charge distribution in a small volume tau surrounding a point O, to the superposition of a monopole, a dipole, a quadrupole and poles of higher moments at the point O: (a) to show that the electrostatic potential due to the charge distribution at an outside point is the same as due to these superposed multipoles (including a monopole). (b) to show that the energy of interaction of an external field with the charge distribution is the same as with the superposed equivalent monopole and multipoles. Neither of these methods gives a physical picture of the equivalence of a charge distribution to the superposition of different multipoles. An attempt is made to interpret in physical terms the emergence of the multipoles of different order, that are equivalent to a charge distribution and to show that the magnitudes of the moments of these multipoles are in agreement with the results of both the approaches (a) and (b). This physical interpretation also helps to understand, in a simple manner, some of the wellknown properties of the multipole moments of atoms and nuclei. (K.B.)
Electric dipole moments reconsidered
International Nuclear Information System (INIS)
Rupertsberger, H.
1989-01-01
The electric dipole moments of elementary particles, atoms, molecules and their connection to the electric susceptibility are discussed for stationary states. Assuming rotational invariance it is emphasized that for such states only in the case of a parity and time reversal violating interaction the considered particles can obtain a nonvanishing expectation value for the electric dipole moment. 1 fig., 13 refs. (Author)
DEFF Research Database (Denmark)
Swann, Andrew Francis; Madsen, Thomas Bruun
2012-01-01
We introduce a notion of moment map adapted to actions of Lie groups that preserve a closed three-form. We show existence of our multi-moment maps in many circumstances, including mild topological assumptions on the underlying manifold. Such maps are also shown to exist for all groups whose second...
Magnetic moment of extremely proton-rich nucleus 23Al
International Nuclear Information System (INIS)
Nagatomo, T; Matsuta, K; Ozawa, A; Nakashima, Y; Matsumiya, R; Mihara, M; Yasuno, T; Chiba, A; Yamada, K; Momota; Ohtsubo, T; Ohta, M; Shinojima, D; Izumikawa, T; Tanaka, H; Yamaguchi, T; Nakajima, S; Maemura, H; Muranaka, K; Kumashiro, S; Fujiwara, H; Yoshida, K; Sumikama, T; Tanaka, K; Ogura, M; Minamisono, K; Fukuda, M; Minamisono, T; Nojiri, Y; Suzuki, T; Tanihata, I; Alonso, J R; Krebs, G F; Symons, T J M
2005-01-01
The g-factor of the extremely proton-rich nucleus 23 Al (T 1/2 = 0.47 s) has been measured by means of the β-NMR method for the first time. The g-factor were determined as |g| = 1.557(88) from the obtained NMR spectra. From the comparison between the experimental value and the shell model calculation, the spin parity of the ground state of 23 Al was determined as I π = 5/2 + . Thus, the magnetic moment of 23 Al was determined as vertical bar μvertical bar = 3.89(22)μ N
Eight piece quadrupole magnet, method for aligning quadrupole magent pole tips
Jaski, Mark S.; Liu, Jie; Donnelly, Aric T.; Downey, Joshua S.; Nudell, Jeremy J.; Jain, Animesh
2018-01-30
The invention provides an alternative to the standard 2-piece or 4-piece quadrupole. For example, an 8-piece and a 10-piece quadrupole are provided whereby the tips of each pole may be adjustable. Also provided is a method for producing a quadrupole using standard machining techniques but which results in a final tolerance accuracy of the resulting construct which is better than that obtained using standard machining techniques.
Schmüdgen, Konrad
2017-01-01
This advanced textbook provides a comprehensive and unified account of the moment problem. It covers the classical one-dimensional theory and its multidimensional generalization, including modern methods and recent developments. In both the one-dimensional and multidimensional cases, the full and truncated moment problems are carefully treated separately. Fundamental concepts, results and methods are developed in detail and accompanied by numerous examples and exercises. Particular attention is given to powerful modern techniques such as real algebraic geometry and Hilbert space operators. A wide range of important aspects are covered, including the Nevanlinna parametrization for indeterminate moment problems, canonical and principal measures for truncated moment problems, the interplay between Positivstellensätze and moment problems on semi-algebraic sets, the fibre theorem, multidimensional determinacy theory, operator-theoretic approaches, and the existence theory and important special topics of multidime...
Multipole moments of water molecules in clusters and ice Ih from first principles calculations
International Nuclear Information System (INIS)
Batista, E.R.; Xantheas, S.S.; Jonsson, H.
1999-01-01
We have calculated molecular multipole moments for water molecules in clusters and in ice Ih by partitioning the charge density obtained from first principles calculations. Various schemes for dividing the electronic charge density among the water molecules were used. They include Bader close-quote s zero flux surfaces and Voronoi partitioning schemes. A comparison was also made with an induction model including dipole, dipole-quadrupole, quadrupole-quadrupole polarizability and first hyperpolarizability as well as fixed octopole and hexadecapole moments. We have found that the different density partitioning schemes lead to widely different values for the molecular multipoles, illustrating how poorly defined molecular multipoles are in clusters and condensed environments. For instance, the magnitude of the molecular dipole moment in ice Ih ranges between 2.3 D and 3.1 D depending on the partitioning scheme used. Within each scheme, though, the value for the molecular dipole moment in ice is larger than in the hexamer. The magnitude of the molecular dipole moment in the clusters shows a monotonic increase from the gas phase value to the one in ice Ih, with the molecular dipole moment in the water ring hexamer being smaller than the one in ice Ih for all the partitioning schemes used. copyright 1999 American Institute of Physics
Zethrenes, Extended p -Quinodimethanes, and Periacenes with a Singlet Biradical Ground State
Sun, Zhe
2014-08-19
ConspectusResearchers have studied polycyclic aromatic hydrocarbons (PAHs) for more than 100 years, and most PAHs in the neutral state reported so far have a closed-shell electronic configuration in the ground state. However, recent studies have revealed that specific types of polycyclic hydrocarbons (PHs) could have a singlet biradical ground state and exhibit unique electronic, optical, and magnetic activities. With the appropriate stabilization, these new compounds could prove useful as molecular materials for organic electronics, nonlinear optics, organic spintronics, organic photovoltaics, and energy storage devices. However, before researchers can use these materials to design new devices, they need better methods to synthesize these molecules and a better understanding of the fundamental relationship between the structure and biradical character of these compounds and their physical properties. Their biradical character makes these compounds difficult to synthesize. These compounds are also challenging to physically characterize and require the use of various experimental techniques and theoretic methods to comprehensively describe their unique properties.In this Account, we will discuss the chemistry and physics of three types of PHs with a significant singlet biradical character, primarily developed in our group. These structures are zethrenes, Z-shaped quinoidal hydrocarbons; hydrocarbons that include a proaromatic extended p-quinodimethane unit; and periacenes, acenes fused in a peri-Arrangement. We used a variety of synthetic methods to prepare these compounds and stabilized them using both thermodynamic and kinetic approaches. We probed their ground-state structures by electronic absorption, NMR, ESR, SQUID, Raman spectroscopy, and X-ray crystallography and also performed density functional theory calculations. We investigated the physical properties of these PHs using various experimental methods such as one-photon absorption, two-photon absorption
Nonuniform radiation damage in permanent magnet quadrupoles.
Danly, C R; Merrill, F E; Barlow, D; Mariam, F G
2014-08-01
We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL's pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.
Nonuniform radiation damage in permanent magnet quadrupoles
International Nuclear Information System (INIS)
Danly, C. R.; Merrill, F. E.; Barlow, D.; Mariam, F. G.
2014-01-01
We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL’s pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components
Nonuniform radiation damage in permanent magnet quadrupoles
Energy Technology Data Exchange (ETDEWEB)
Danly, C. R.; Merrill, F. E.; Barlow, D.; Mariam, F. G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)
2014-08-15
We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL’s pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.
AA, shims and washers on quadrupole ends
CERN PhotoLab
1981-01-01
Due to the fact that much of the field of the quadrupoles was outside the iron (in particular with the wide quadrupoles) and that thus the fields of quadrupoles and bending magnets interacted, the lattice properties of the AA could not be predicted with the required accuracy. After a first running period in 1980, during which detailed measurements were made with proton test beams, corrections to the quadrupoles were made in 1981, in the form of laminated shims at the ends of the poles, and with steel washers. With the latter ones, further refinements were made in an iterative procedure with measurements on the circulating beam. This eventually resulted, amongst other things, in a very low chromaticity, with the Q-values being constant to within +- 0.001 over the total momentum range of 6 %. Here we see the shims and washers on a narrow qudrupole (QFN, QDN). See also 8103203, 8103204, 8103205, 8103206.
Puzzle of magnetic moments of Ni clusters revisited using quantum Monte Carlo method.
Lee, Hung-Wen; Chang, Chun-Ming; Hsing, Cheng-Rong
2017-02-28
The puzzle of the magnetic moments of small nickel clusters arises from the discrepancy between values predicted using density functional theory (DFT) and experimental measurements. Traditional DFT approaches underestimate the magnetic moments of nickel clusters. Two fundamental problems are associated with this puzzle, namely, calculating the exchange-correlation interaction accurately and determining the global minimum structures of the clusters. Theoretically, the two problems can be solved using quantum Monte Carlo (QMC) calculations and the ab initio random structure searching (AIRSS) method correspondingly. Therefore, we combined the fixed-moment AIRSS and QMC methods to investigate the magnetic properties of Ni n (n = 5-9) clusters. The spin moments of the diffusion Monte Carlo (DMC) ground states are higher than those of the Perdew-Burke-Ernzerhof ground states and, in the case of Ni 8-9 , two new ground-state structures have been discovered using the DMC calculations. The predicted results are closer to the experimental findings, unlike the results predicted in previous standard DFT studies.
Superfluid quenching of the moment of inertia in a strongly interacting Fermi gas
Riedl, S.; Sánchez Guajardo, E. R.; Kohstall, C.; Hecker Denschlag, J.; Grimm, R.
2011-03-01
We report on the observation of a quenched moment of inertia resulting from superfluidity in a strongly interacting Fermi gas. Our method is based on setting the hydrodynamic gas in slow rotation and determining its angular momentum by detecting the precession of a radial quadrupole excitation. The measurements distinguish between the superfluid and collisional origins of hydrodynamic behavior, and show the phase transition.
Laser measurements of radii and moments of barium nuclei near the proton drip line
International Nuclear Information System (INIS)
Eastham; Smith, J.R.H.; Groves, J.
1987-01-01
A new technique of laser spectroscopy has been used to measure the magnetic dipole and electric quadrupole moment of /sup 121/Ba, and the r.m.s. charge radii of /sup 120,121/Ba. The results are discussed in terms of the unified model
Nuclei quadrupole coupling constants in diatomic molecule
International Nuclear Information System (INIS)
Ivanov, A.I.; Rebane, T.K.
1993-01-01
An approximate relationship between the constants of quadrupole interaction of nuclei in a two-atom molecule is found. It enabled to establish proportionality of oscillatory-rotation corrections to these constants for both nuclei in the molecule. Similar results were obtained for the factors of electrical dipole-quadrupole screening of nuclei. Applicability of these relationships is proven by the example of lithium deuteride molecule. 4 refs., 1 tab
AA, wide quadrupole on measurement stand
CERN PhotoLab
1981-01-01
Please look up 8101024 first. Shims and washers on the wide quadrupoles (QFW, QDW; located in the lattice where dispersion was large) served mostly for corrections of those lattice parameters which were a function of momentum. After mounting shims and washers, the quadrupoles were measured to determine their magnetic centre and to catalogue the effect of washer constellations. Raymond Brown is busy measuring a wide quad.