Reduction of a Z(3) gauge theory on the flat lattices to the spin-1 BEG model

International Nuclear Information System (INIS)

Ananikian, N.S.; Shcherbakov, R.R.

1995-01-01

The Z(3) gauge model with double plaquette representation of the action on the flat triangular and square lattices is constructed. It is reduced to the spin-1 Blume-Emery-Griffiths (BEG) model. An Ising-type critical line of a second-order phase transition is found. ((orig.))

Effective Hamiltonian for 2-dimensional arbitrary spin Ising model

International Nuclear Information System (INIS)

Sznajd, J.; Polska Akademia Nauk, Wroclaw. Inst. Niskich Temperatur i Badan Strukturalnych)

1983-08-01

The method of the reduction of the generalized arbitrary-spin 2-dimensional Ising model to spin-half Ising model is presented. The method is demonstrated in detail by calculating the effective interaction constants to the third order in cumulant expansion for the triangular spin-1 Ising model (the Blume-Emery-Griffiths model). (author)

Multicritical dynamical phase diagrams of the kinetic Blume-Emery-Griffiths model with repulsive biquadratic coupling in an oscillating field

Energy Technology Data Exchange (ETDEWEB)

Temizer, Umuet [Department of Physics, Bozok University, 66100 Yozgat (Turkey); Kantar, Ersin [Institute of Science, Erciyes University, 38039 Kayseri (Turkey); Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)], E-mail: keskin@erciyes.edu.tr; Canko, Osman [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

2008-06-15

We study, within a mean-field approach, the stationary states of the kinetic Blume-Emery-Griffiths model with repulsive biquadratic coupling under the presence of a time-varying (sinusoidal) magnetic field. We employ the Glauber-type stochastic dynamics to construct set of dynamic equations of motion. The behavior of the time dependence of the order parameters and the behavior of the average order parameters in a period, which is also called the dynamic order parameters, as functions of the reduced temperature are investigated. The dynamic phase transition points are calculated and phase diagrams are presented in the reduced magnetic field amplitude and reduced temperature plane. The dynamical transition from one regime to the other can be of first- or second order depending on the region in the phase diagram. According to the values of the crystal field interaction or single-ion anisotropy constant and biquadratic exchange constant, we find 20 fundamental types of phase diagrams which exhibit many dynamic critical points, such as tricritical points, zero-temperature critical points, double critical end points, critical end point, triple point and multicritical point. Moreover, besides a disordered and ordered phases, seven coexistence phase regions exist in the system.

Multicritical phase diagrams of the Blume-Emery-Griffiths model with repulsive biquadratic coupling including metastable phases: the pair approximation and the path probability method with pair distribution

International Nuclear Information System (INIS)

Keskin, Mustafa; Erdinc, Ahmet

2004-01-01

As a continuation of the previously published work, the pair approximation of the cluster variation method is applied to study the temperature dependences of the order parameters of the Blume-Emery-Griffiths model with repulsive biquadratic coupling on a body centered cubic lattice. We obtain metastable and unstable branches of the order parameters besides the stable branches and phase transitions of these branches are investigated extensively. We study the dynamics of the model by the path probability method with pair distribution in order to make sure that we find and define the metastable and unstable branches of the order parameters completely and correctly. We present the metastable phase diagram in addition to the equilibrium phase diagram and also the first-order phase transition line for the unstable branches of the quadrupole order parameter is superimposed on the phase diagrams. It is found that the metastable phase diagram and the first-order phase boundary for the unstable quadrupole order parameter always exist at the low temperatures which are consistent with experimental and theoretical works

Critical regions with central charge c=1/2,7/10,4/5 in the spin-1 quantum chain

International Nuclear Information System (INIS)

Mueller, E.

1991-01-01

The phase diagramm of the Blume-Emery-Griffiths spin-1-quantum chain is calculated by finite-size scaling with respect to all four parameters. We locate the three-dimensional critical manifold and determine a two-dimensional tricritical surface where the spectra exhibit conformal invariance corresponding to the central charges c=7/10 and 4/5. Choosing one parameter to be zero, we can treat the model analytically and from this the spectrum on a large part of the Ising-like critical region can be understood: there the spectrum consists of conformal c=1/2-levels on which a massive spectrum is superimposed. Calculating three-point functions we study which perturbations by primary fields lead from c=4/5 or c=7/10-critical points to Ising-type regions. (orig.) [de

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

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.

Maximum Entropy Estimation of Transition Probabilities of Reversible Markov Chains

Directory of Open Access Journals (Sweden)

Erik Van der Straeten

2009-11-01

Full Text Available In this paper, we develop a general theory for the estimation of the transition probabilities of reversible Markov chains using the maximum entropy principle. A broad range of physical models can be studied within this approach. We use one-dimensional classical spin systems to illustrate the theoretical ideas. The examples studied in this paper are: the Ising model, the Potts model and the Blume-Emery-Griffiths model.

A renormalization-group analysis of a spin-1 Ising ferromagnet with competing crystal-field and repulsive biquadratic interactions

International Nuclear Information System (INIS)

Snowman, Daniel P.

2009-01-01

Phase diagrams have been produced and critical exponents calculated for a Blume-Emery-Griffiths system with competing biquadratic and crystal-field interactions with uniform ferromagnetic bilinear interactions. This competition directly effects the clustering and density of nonmagnetic impurities. These results have been produced using renormalization-group methods with a hierarchical lattice. A series of planes of constant, repulsive biquadratic coupling have been probed while varying the temperature and concentration of annealed vacancies in the system. The sinks have been analyzed and interpreted, and critical exponents calculated for the higher order transitions.

Mixed spin-((1)/(2)) and spin-1 Blume-Capel Ising ferrimagnetic system on the Bethe lattice

International Nuclear Information System (INIS)

Albayrak, Erhan; Keskin, Mustafa

2003-01-01

The mixed spin-((1)/(2)) and spin-1 Blume-Capel Ising ferrimagnetic system is studied on the Bethe lattice by using the exact recursion equations. Exact expressions for the magnetization, the quadrupolar moment, the Curie temperature and the free energy are found and the phase diagrams are constructed on the Bethe lattice with the coordination numbers q=3, 4, 5 and 6. The existence of a tricritical point is investigated for different values of q. The results are compared with those of other approximate methods and with the exact result on the Bethe lattice by using a discrete nonlinear map and also the exact results that are available for the case of the honeycomb lattice

Generalized partition function zeros of 1D spin models and their critical behavior at edge singularities

International Nuclear Information System (INIS)

Dalmazi, D; Sa, F L

2010-01-01

Here we study the partition function zeros of the one-dimensional Blume-Emery-Griffiths model close to their edge singularities. The model contains four couplings (H, J, Δ, K) including the magnetic field H and the Ising coupling J. We assume that only one of the three couplings (J, Δ, K) is complex and the magnetic field is real. The generalized zeros z i tend to form continuous curves on the complex z-plane in the thermodynamic limit. The linear density at the edges z E diverges usually with ρ(z) ∼ |z - z E | σ and σ = -1/2. However, as in the case of complex magnetic fields (Yang-Lee edge singularity), if we have a triple degeneracy of the transfer matrix eigenvalues a new critical behavior with σ = -2/3 can appear as we prove here explicitly for the cases where either Δ or K is complex. Our proof applies for a general three-state spin model with short-range interactions. The Fisher zeros (complex J) are more involved; in practice, we have not been able to find an explicit example with σ = -2/3 as far as the other couplings (H, Δ, K) are kept as real numbers. Our results are supported by numerical computations of zeros. We show that it is absolutely necessary to have a non-vanishing magnetic field for a new critical behavior. The appearance of σ = -2/3 at the edge closest to the positive real axis indicates its possible relevance for tricritical phenomena in higher-dimensional spin models.

The phase diagrams and compensation behaviors of mixed spin Blume-Capel model in a trimodal magnetic field

Energy Technology Data Exchange (ETDEWEB)

Zhang, Y.F. [Department of Physics, Suzhou University, Suzhou 215006 (China); Yan, S.L. [Department of Physics, Suzhou University, Suzhou 215006 (China); Jiangsu Key Loboratory of Film Materials, Suzhou University, Suzhou 215006 (China); CCAST (World Laboratory), PO Box 8730, Beijing 100080 (China)], E-mail: slyan@suda.edu.cn

2008-04-07

The phase diagrams and compensation behaviors of mixed spin-1/2 and spin-1 Blume-Capel model in a trimodal magnetic field are investigated in the framework of the effective field theory on simple cubic lattice. The change of negative crystal field and trimodal concentration can affect the TCP, the second-order phase and the magnetic field degeneration at ground state in T-H space. In T-D space, the trajectory of the TCP takes on the acre curve and there exist the two TCPs under certain condition. In addition to giving one or two compensation temperature points in M-T space, the mixed spin Blume-Capel model also provides one or two novel compensation magnetic field points in M-H space. Some results are not revealed in previous works.

Dynamic magnetic hysteresis behavior and dynamic phase transition in the spin-1 Blume-Capel model

Energy Technology Data Exchange (ETDEWEB)

Deviren, Bayram, E-mail: bayram.deviren@nevsehir.edu.tr [Department of Physics, Nevsehir University, 50300 Nevsehir (Turkey); Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

2012-03-15

The nature (time variation) of response magnetization m(wt) of the spin-1 Blume-Capel model in the presence of a periodically varying external magnetic field h(wt) is studied by employing the effective-field theory (EFT) with correlations as well as the Glauber-type stochastic dynamics. We determine the time variations of m(wt) and h(wt) for various temperatures, and investigate the dynamic magnetic hysteresis behavior. We also investigate the temperature dependence of the dynamic magnetization, hysteresis loop area and correlation near the transition point in order to characterize the nature (first- or second-order) of the dynamic transitions as well as obtain the dynamic phase transition temperatures. The hysteresis loops are obtained for different reduced temperatures and we find that the areas of the loops are decreasing with the increasing of the reduced temperatures. We also present the dynamic phase diagrams and compare the results of the EFT with the results of the dynamic mean-field approximation. The phase diagrams exhibit many dynamic critical points, such as tricritical ( Bullet ), zero-temperature critical (Z), triple (TP) and multicritical (A) points. According to values of Hamiltonian parameters, besides the paramagnetic (P), ferromagnetic (F) fundamental phases, one coexistence or mixed phase region, (F+P) and the reentrant behavior exist in the system. The results are in good agreement with some experimental and theoretical results. - Highlights: Black-Right-Pointing-Pointer Kinetic spin-1 Blume-Capel model is studied using the effective-field theory. Black-Right-Pointing-Pointer We investigated the dynamic magnetic hysteresis behavior. Black-Right-Pointing-Pointer Dynamic magnetization, hysteresis loop area and correlation are investigated. Black-Right-Pointing-Pointer System exhibits tricritical, zero-temperature, triple and multicritical points. Black-Right-Pointing-Pointer We present the dynamic phase diagrams and compare the results of the EFT

A new effective correlation mean-field theory for the ferromagnetic spin-1 Blume-Capel model in a transverse crystal field

Science.gov (United States)

Roberto Viana, J.; Rodriguez Salmon, Octavio D.; Neto, Minos A.; Carvalho, Diego C.

2018-02-01

A new approximation technique is developed so as to study the quantum ferromagnetic spin-1 Blume-Capel model in the presence of a transverse crystal field in the square lattice. Our proposal consists of approaching the spin system by considering islands of finite clusters whose frontiers are surrounded by noninteracting spins that are treated by the effective-field theory. The resulting phase diagram is qualitatively correct, in contrast to most effective-field treatments, in which the first-order line exhibits spurious behavior by not being perpendicular to the anisotropy axis at low-temperatures. The effect of the transverse anisotropy is also verified by the presence of quantum phase transitions. The possibility of using larger sizes constitutes an advantage to other approaches where the implementation of larger sizes is computationally costly.

Three-critical phenomena in the He3-He4 mixture

International Nuclear Information System (INIS)

Carvalho Filho, C.A.A. de.

1976-07-01

A review of the phenomenology of tricritical behaviour in He 3 -He 4 mixtures is made. Starting from a model proposed by Blume, Emery and Griffiths the tricritical transition is investigated by means of the Renormalization Group making use of the Callan-Symanzik equation and usual perturbative methods of Relativistic Quantum Field Theory. Mean-field tricritical exponents and logarithmic corrections are found in a sup(n) unified context. The structure of scaling laws is also studied. (author) [pt

Multicritical phase diagrams of the antiferromagnetic spin-3/2 Blume-Capel model

Energy Technology Data Exchange (ETDEWEB)

Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)]. E-mail: keskin@erciyes.edu.tr; Ali Pinar, M. [Institute of Science, Erciyes University, 38039 Kayseri (Turkey); Erdinc, Ahmet [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Canko, Osman [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

2006-04-24

The antiferromagnetic spin-3/2 Blume-Capel model in an external magnetic field is investigated, and the phase diagrams are obtained in detail by using the cluster variation method. The model exhibits distinct critical regions, including the first-order, second-order and special points: two double critical points, a critical end point, a tricritical point and a zero-temperature critical point. The new phase diagram topology is also found that was not obtained previously. Comparison of the results with those of other studies on this, and closely related systems, is made.

Multicritical phase diagrams of the antiferromagnetic spin-3/2 Blume-Capel model

International Nuclear Information System (INIS)

Keskin, Mustafa; Ali Pinar, M.; Erdinc, Ahmet; Canko, Osman

2006-01-01

The antiferromagnetic spin-3/2 Blume-Capel model in an external magnetic field is investigated, and the phase diagrams are obtained in detail by using the cluster variation method. The model exhibits distinct critical regions, including the first-order, second-order and special points: two double critical points, a critical end point, a tricritical point and a zero-temperature critical point. The new phase diagram topology is also found that was not obtained previously. Comparison of the results with those of other studies on this, and closely related systems, is made

Dynamic phase transition in the kinetic spin-1 Blume-Capel model: Phase diagrams in the temperature and crystal-field interaction plane

International Nuclear Information System (INIS)

Keskin, M.; Canko, O.; Temizer, U.

2007-01-01

Within a mean-field approach, the stationary states of the kinetic spin-1 Blume-Capel model in the presence of a time-dependent oscillating external magnetic field is studied. The Glauber-type stochastic dynamics is used to describe the time evolution of the system and obtain the mean-field dynamic equation of motion. The dynamic phase-transition points are calculated and phase diagrams are presented in the temperature and crystal-field interaction plane. According to the values of the magnetic field amplitude, three fundamental types of phase diagrams are found: One exhibits a dynamic tricritical point, while the other two exhibit a dynamic zero-temperature critical point

The spin-3/2 Blume-Capel model on the Bethe lattice using the recursion method

International Nuclear Information System (INIS)

Albayrak, Erhan; Keskin, Mustafa

2000-01-01

The spin-3/2 Blume-Capel model is solved on the Bethe lattice using the exact recursion equations. The nature of the variation of the Curie temperature with the ratio of the single-ion anisotropy term to the exchange-coupling constant is studied and the phase diagrams are constructed on the Bethe lattice with the co-ordination numbers q=3 and 6. A comparison is made with the results of the other approximation schemes

The spin-3/2 Blume-Capel model on the Bethe lattice using the recursion method

CERN Document Server

Albayrak, E

2000-01-01

The spin-3/2 Blume-Capel model is solved on the Bethe lattice using the exact recursion equations. The nature of the variation of the Curie temperature with the ratio of the single-ion anisotropy term to the exchange-coupling constant is studied and the phase diagrams are constructed on the Bethe lattice with the co-ordination numbers q=3 and 6. A comparison is made with the results of the other approximation schemes.

Luther-Emery liquid in the NMR relaxation rate of carbon nanotubes

International Nuclear Information System (INIS)

Gulacsi, Miklos; Simon, Ferenc; Wzietek, Pawel; Kuzmany, Hans; Dora, Balazs

2008-01-01

We analyze a recent NMR experiments by Singer et al.[Singer et al. Phys. Rev. Lett. 95, 236403 (2005).], which showed a deviation from Fermi-liquid behavior in carbon nanotubes with an energy gap evident at low temperatures. A comprehensive theory for the magnetic field and temperature dependent NMR 13 C spin-lattice relaxation is given in the framework of the Luther-Emery and Luttinger liquids. The low temperature properties are governed by a gapped relaxation due to a spin gap (∝30 K), described by the Luther-Emery liquid picture, which crosses over smoothly to the Luttinger liquid behaviour with increasing temperature. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Magnetocaloric properties of a frustrated Blume-Capel antiferromagnet

Directory of Open Access Journals (Sweden)

Žukovič Milan

2014-07-01

Full Text Available Low-temperature magnetization processes and magnetocaloric properties of a geometrically frustrated spin-1 Blume-Capel model on a triangular lattice are studied by Monte Carlo simulations. The model is found to display qualitatively different behavior depending on the sign of the single-ion anisotropy D. For positive values of D we observe two magnetization plateaus, similar to the spin-1/2 Ising antiferromagnet, and negative isothermal entropy changes for any field intensity. For a range of small negative values of D there are four magnetization plateaus and the entropy changes can be either negative or positive, depending on the field. If D is negative but large in absolute value then the entropy changes are solely positive.

Luther-Emery Phase and Atomic-Density Waves in a Trapped Fermion Gas

International Nuclear Information System (INIS)

Gao Xianlong; Rizzi, M.; Polini, Marco; Tosi, M. P.; Fazio, Rosario; Campo, V. L. Jr.; Capelle, K.

2007-01-01

The Luther-Emery liquid is a state of matter that is predicted to occur in one-dimensional systems of interacting fermions and is characterized by a gapless charge spectrum and a gapped spin spectrum. In this Letter we discuss a realization of the Luther-Emery phase in a trapped cold-atom gas. We study by means of the density-matrix renormalization-group technique a two-component atomic Fermi gas with attractive interactions subject to parabolic trapping inside an optical lattice. We demonstrate how this system exhibits compound phases characterized by the coexistence of spin pairing and atomic-density waves. A smooth crossover occurs with increasing magnitude of the atom-atom attraction to a state in which tightly bound spin-singlet dimers occupy the center of the trap. The existence of atomic-density waves could be detected in the elastic contribution to the light-scattering diffraction pattern

Signature of Griffith phase in (Tb1-xCex)MnO3

Science.gov (United States)

Kumar, Abhishek; Dwivedi, G. D.; Singh, A.; Singh, R.; Shukla, K. K.; Yang, H. D.; Ghosh, A. K.; Chatterjee, Sandip

2016-05-01

Griffith phase phenomena is attributed to existence of FM (ferromagnetic) cluster in AFM (antiferromagnetic) ordering which usually occurs in ferromagnetic and antiferromagnetic bilayers or multilayers. In (Tb1-xCex)MnO3 evolution of Griffith phase have been observed. The observed Griffith phase might be due to the exchange interaction between Mn3+/Mn2+ states.

Critical and Griffiths-McCoy singularities in quantum Ising spin glasses on d -dimensional hypercubic lattices: A series expansion study

Science.gov (United States)

Singh, R. R. P.; Young, A. P.

2017-08-01

We study the ±J transverse-field Ising spin-glass model at zero temperature on d -dimensional hypercubic lattices and in the Sherrington-Kirkpatrick (SK) model, by series expansions around the strong-field limit. In the SK model and in high dimensions our calculated critical properties are in excellent agreement with the exact mean-field results, surprisingly even down to dimension d =6 , which is below the upper critical dimension of d =8 . In contrast, at lower dimensions we find a rich singular behavior consisting of critical and Griffiths-McCoy singularities. The divergence of the equal-time structure factor allows us to locate the critical coupling where the correlation length diverges, implying the onset of a thermodynamic phase transition. We find that the spin-glass susceptibility as well as various power moments of the local susceptibility become singular in the paramagnetic phase before the critical point. Griffiths-McCoy singularities are very strong in two dimensions but decrease rapidly as the dimension increases. We present evidence that high enough powers of the local susceptibility may become singular at the pure-system critical point.

Kinetics of the spin-2 Blume-Capel model under a time-dependent oscillating external field

International Nuclear Information System (INIS)

Keskin, M.; Canko, O.; Ertas, M.

2007-01-01

Within a mean-field approach and using the Glauber-type stochastic dynamics, we study the kinetics of the spin-2 Blume-Capel model in the presence of a time-varying (sinusoidal) magnetic field. We investigate the time dependence of the average order parameter and the behavior of the average order parameter in a period, which is also called the dynamic order parameter, as a function of the reduced temperature. The nature (continuous and discontinuous) of the transition is characterized by the dynamic order parameter. The dynamic phase transition points are obtained and the phase diagrams are presented in the reduced magnetic field amplitude and reduced temperature plane. The phase diagrams exhibit one dynamic tricritical point; besides a disordered and an ordered phases, there are three phase coexistence regions that are strongly dependent on the interaction parameter

Tri-critical behavior of the Blume Capel model on a diamond lattice

Energy Technology Data Exchange (ETDEWEB)

Santos, Jander P., E-mail: jander@ufsj.edu.br [Departamento de Ciências Naturais, Universidade Federal de São João del Rei, C.P. 110, CEP 36301-160 São João del Rei, MG (Brazil); Departamento de Matemática, Universidade Federal de São João del Rei, C.P. 110, CEP 36301-160 São João del Rei, MG (Brazil); Sá Barreto, F.C., E-mail: fcsabarreto@gmail.com [Departamento de Ciências Naturais, Universidade Federal de São João del Rei, C.P. 110, CEP 36301-160 São João del Rei, MG (Brazil); Emeritus Professor, Departamento de Física, Universidade Federal de Minas Gerais, C.P. 110, CEP 31270-901 Belo Horizonte, MG (Brazil); Rosa, D.S., E-mail: derick@ift.unesp.br [Instituto de Física Teórica, Universidade Estadual Paulista, C.P. 110, CEP 01140-070 São Paulo, SP (Brazil)

2017-02-01

The mean field approximation results are obtained in a five-site cluster on the diamond lattice from the Bogoliubov inequality. Spin correlation identities for the Blume-Capel model on diamond lattice are derived from a five-site cluster and used to obtain an effective field approximation. The free-energy, magnetization, critical frontiers and tricritical points are obtained from the mean field approximation and the effective field approximation and are compared to those obtained by other methods. From the mean-field approximation, we also studied the unstable and metastable states besides the stable states present in the model. - Highlights: • From the Bogoliubov inequality the mean field approximation is applied. • Correlation identities for the Blume-Capel model on a diamond lattice are obtained. • From the spin correlation identities the effective-field theory is applied. • Lines of phase transitions of first order and continuous are obtained. • Multicritical points are obtained according to this procedure.

Modeling premartensitic effects in Ni2MnGa: A mean-field and Monte Carlo simulation study

DEFF Research Database (Denmark)

Castan, T.; Vives, E.; Lindgård, Per-Anker

1999-01-01

is constructed and justified based on the analysis of the experimentally observed strain variables and precursor phenomena. The description includes the (local) tetragonal distortion, the amplitude of the plane-modulating strain, and the magnetization. The model is solved by means of mean-field theory and Monte......The degenerate Blume-Emery-Griffiths model for martensitic transformations is extended by including both structural and magnetic degrees of freedom in order to elucidate premartensitic effects. Special attention is paid to the effect of the magnetoelastic coupling in Ni2MnGa. The microscopic model...... heat, not always associated with a true phase transition. The main conclusion is that premartensitic effects result from the interplay between the softness of the anomalous phonon driving the modulation and the magnetoelastic coupling. In particular, the premartensitic transition occurs when...

Dynamic phase transition in the kinetic spin-32 Blume-Capel model: Phase diagrams in the temperature and crystal-field interaction plane

Energy Technology Data Exchange (ETDEWEB)

Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)]. E-mail: keskin@erciyes.edu.tr; Canko, Osman [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Deviren, Bayram [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

2007-06-15

We analyze, within a mean-field approach, the stationary states of the kinetic spin-32 Blume-Capel (BC) model by the Glauber-type stochastic dynamics and subject to a time-dependent oscillating external magnetic field. The dynamic phase transition (DPT) points are obtained by investigating the behavior of the dynamic magnetization as a function of temperature and as well as calculating the Liapunov exponent. Phase diagrams are constructed in the temperature and crystal-field interaction plane. We find five fundamental types of phase diagrams for the different values of the reduced magnetic field amplitude parameter (h) in which they present a disordered, two ordered phases and the coexistences phase regions. The phase diagrams also exhibit a dynamic double-critical end point for 01.44, one dynamic tricritical point for 1.445.06.

Blume-Capel ferromagnet driven by propagating and standing magnetic field wave: Dynamical modes and nonequilibrium phase transition

Energy Technology Data Exchange (ETDEWEB)

Acharyya, Muktish, E-mail: muktish.physics@presiuniv.ac.in; Halder, Ajay, E-mail: ajay.rs@presiuniv.ac.in

2017-03-15

The dynamical responses of Blume-Capel (S=1) ferromagnet to the plane propagating (with fixed frequency and wavelength) and standing magnetic field waves are studied separately in two dimensions by extensive Monte Carlo simulation. Depending on the values of temperature, amplitude of the propagating magnetic field and the strength of anisotropy, two different dynamical phases are observed. For a fixed value of anisotropy and the amplitude of the propagating magnetic field, the system undergoes a dynamical phase transition from a driven spin wave propagating phase to a pinned or spin frozen state as the system is cooled down. The time averaged magnetisation over a full cycle of the propagating magnetic field plays the role of the dynamic order parameter. A comprehensive phase diagram is plotted in the plane formed by the amplitude of the propagating wave and the temperature of the system. It is found that the phase boundary shrinks inward as the anisotropy increases. The phase boundary, in the plane described by the strength of the anisotropy and temperature, is also drawn. This phase boundary was observed to shrink inward as the field amplitude increases. - Highlights: • The Blume-Capel ferromagnet in propagating and standing magnetic wave. • Monte Carlo single spin flip Metropolis algorithm is employed. • The dynamical modes are observed. • The nonequilibrium phase transitions are studied. • The phase boundaries are drawn.

Dynamic phase transition in the kinetic spin-32 Blume-Capel model: Phase diagrams in the temperature and crystal-field interaction plane

International Nuclear Information System (INIS)

Keskin, Mustafa; Canko, Osman; Deviren, Bayram

2007-01-01

We analyze, within a mean-field approach, the stationary states of the kinetic spin-32 Blume-Capel (BC) model by the Glauber-type stochastic dynamics and subject to a time-dependent oscillating external magnetic field. The dynamic phase transition (DPT) points are obtained by investigating the behavior of the dynamic magnetization as a function of temperature and as well as calculating the Liapunov exponent. Phase diagrams are constructed in the temperature and crystal-field interaction plane. We find five fundamental types of phase diagrams for the different values of the reduced magnetic field amplitude parameter (h) in which they present a disordered, two ordered phases and the coexistences phase regions. The phase diagrams also exhibit a dynamic double-critical end point for 0 5.06

Dynamical replica analysis of processes on finitely connected random graphs: II. Dynamics in the Griffiths phase of the diluted Ising ferromagnet

International Nuclear Information System (INIS)

Mozeika, A; Coolen, A C C

2009-01-01

We study the Glauber dynamics of Ising spin models with random bonds, on finitely connected random graphs. We generalize a recent dynamical replica theory with which to predict the evolution of the joint spin-field distribution, to include random graphs with arbitrary degree distributions. The theory is applied to Ising ferromagnets on randomly diluted Bethe lattices, where we study the evolution of the magnetization and the internal energy. It predicts a prominent slowing down of the flow in the Griffiths phase, it suggests a further dynamical transition at lower temperatures within the Griffiths phase, and it is verified quantitatively by the results of Monte Carlo simulations

New performance data for {open_quotes}Emery 3002{close_quotes} and {open_quotes}Emery 3004,{close_quotes} two Army-approved safe materials to replace DOP in mask and filter testing

Energy Technology Data Exchange (ETDEWEB)

Carlon, H.R.; Guelta, M.A. [Army Edgewood Research, Development and Engineering Center, Aberdeen Proving Ground, MD (United States)

1995-02-01

At the 22nd Conference in Denver, we reported that the U.S. Army Surgeon General (SGJ) had approved our developmental material {open_quotes}Emery 3004{close_quotes} as a safe replacement for the suspected carcinogen DOP (dioctyl phthalate) in mask and filter testing throughout the Army. Subsequently the SG approved a second, less viscous material, {open_quotes}Emery 3002,{close_quotes} for similar applications. We have measured the viscosities and surface tensions of these liquids over a wide range of temperatures, and have initiated liquid breakup studies through Laskin and two-fluid nozzles. New measurements have been carried out with both liquids, e.g. using the ATI, Inc., TDA-4A cold generator to disperse aerosols for which droplet size distributions were measured using the TSI, Inc., Differential Mobility Particle Sizer (DMPS). Among the findings were that Emery 3004 performs much like DOP in the TDA-4A, with some possible advantages, while Emery 3002 in the TDA-4A produces mean droplet diameters about one-half those of Emery 3004 or DOP. This suggests that Emery 3002 could yield more rigorous filter tests with a smaller consumption of material. New laboratory results will be summarized. Sources of the {open_quotes}Emery{close_quotes} materials will be discussed since the production facility formerly operated by Emery is now run by the Ethyl Corporation and the source products are now known as {open_quotes}Ethylflo 192{close_quotes} (Emery 3002) and{open_quotes}Ethylflo 194{close_quotes} (Emery 3004).

Existence of Griffiths phase in La0.67Ca0.33Mn0.93Fe0.07O3

International Nuclear Information System (INIS)

Joshi, L.; Dayal, V.; Rama, N.; Keshri, S.

2009-01-01

Temperature variation of electrical resistivity, AC susceptibility and electron spin resonance measurements are reported for La 0.67 Ca 0.33 Mn 0.93 Fe 0.07 O 3 . The inverse of AC susceptibility shows a downturn with decreasing temperature before T c indicating the existence of Griffiths phase for the temperature range T c ≤ T ≤ T G , where T G is the Griffiths temperature. The ESR results show the existence of FM clusters in the PM region above T c which supports the presence of Griffiths phase. The ESR results also show the existence of inhomogeneous distribution of magnetic phases in the sample. A possible mechanism of the obtained results has been explained.

Dynamic phase transitions and dynamic phase diagrams of the spin-2 Blume-Capel model under an oscillating magnetic field within the effective-field theory

Energy Technology Data Exchange (ETDEWEB)

Ertas, Mehmet [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Institute of Science, Erciyes University, 38039 Kayseri (Turkey); Deviren, Bayram [Department of Physics, Nevsehir University, 50300 Nevsehir (Turkey); Keskin, Mustafa, E-mail: keskin@erciyes.edu.tr [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

2012-03-15

The dynamic phase transitions are studied in the kinetic spin-2 Blume-Capel model under a time-dependent oscillating magnetic field using the effective-field theory with correlations. The effective-field dynamic equation for the average magnetization is derived by employing the Glauber transition rates and the phases in the system are obtained by solving this dynamic equation. The nature (first- or second-order) of the dynamic phase transition is characterized by investigating the thermal behavior of the dynamic magnetization and the dynamic phase transition temperatures are obtained. The dynamic phase diagrams are constructed in the reduced temperature and magnetic field amplitude plane and are of seven fundamental types. Phase diagrams contain the paramagnetic (P), ferromagnetic-2 (F{sub 2}) and three coexistence or mixed phase regions, namely the F{sub 2}+P, F{sub 1}+P and F{sub 2}+F{sub 1}+P, which strongly depend on the crystal-field interaction (D) parameter. The system also exhibits the dynamic tricritical behavior. - Highlights: Black-Right-Pointing-Pointer Dynamic phase transitions are studied in spin-2 BC model using EFT. Black-Right-Pointing-Pointer Dynamic phase diagrams are constructed in (T/zJ, h/zJ) plane. Black-Right-Pointing-Pointer Seven fundamental types of dynamic phase diagrams are found in the system. Black-Right-Pointing-Pointer System exhibits dynamic tricritical behavior.

Ferrimagnetic Properties of Bond Dilution Mixed Blume-Capel Model with Random Single-Ion Anisotropy

International Nuclear Information System (INIS)

Liu Lei; Yan Shilei

2005-01-01

We study the ferrimagnetic properties of spin 1/2 and spin-1 systems by means of the effective field theory. The system is considered in the framework of bond dilution mixed Blume-Capel model (BCM) with random single-ion anisotropy. The investigation of phase diagrams and magnetization curves indicates the existence of induced magnetic ordering and single or multi-compensation points. Special emphasis is placed on the influence of bond dilution and random single-ion anisotropy on normal or induced magnetic ordering states and single or multi-compensation points. Normal magnetic ordering states take on new phase diagrams with increasing randomness (bond and anisotropy), while anisotropy induced magnetic ordering states are always occurrence no matter whether concentration of anisotropy is large or small. Existence and disappearance of compensation points rely strongly on bond dilution and random single-ion anisotropy. Some results have not been revealed in previous papers and predicted by Neel theory of ferrimagnetism.

Evidence of emerging Griffiths singularity in La{sub 0.5} Sr{sub 0.5} MnO{sub 3} nanocrystalline probed by magnetization and electron paramagnetic resonance

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiyuan [Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Fan, Jiyu, E-mail: jiyufan@nuaa.edu.cn [Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Xu, Lisa [Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Tong, Wei [High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031 (China); Hu, Dazhi [Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); He, Xun [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Zhang, Lei; Pi, Li; Zhang, Yuheng [High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031 (China)

2016-06-01

We present an investigation of Griffiths singularity in La{sub 0.5} Sr{sub 0.5} MnO{sub 3} nanocrystalline by means of magnetic susceptibility and electron paramagnetic resonance (EPR). An unusual platform was found in paramagnetic region. Based on the analysis of EPR spectrum and magnetization variation across the whole temperature range of phase transition, we confirm it is due to the presence of Griffiths singularity rather than a superparamagnetic state in the nanocrystalline system. Such a singularity phase is constituted with some correlated ferromagnetic clusters which embed in paramagnetic matrix. Although they form ferromagnetic spin correlation, the system do not yield any spontaneous magnetization. According to core–shell model, the emergence of Griffiths singularity can be considered due to the presence of local ferromagnetic fluctuations originated from surface spin disorder as the sample size is confined to nanoscale. - Highlights: • Griffiths singularity rather than superparamagnetism occurs in La{sub 0.5}Sr{sub 0.5}MnO{sub 3} nanoparticals. • The sample’s size reduced to nanoscale results in the short-range ferromagnetic interaction. • The core-shell model is used to understand the formation of Griffiths phase in nanometer La{sub 0.5}Sr{sub 0.5}MnO{sub 3}.

Exactly solved mixed spin-(1,1/2) Ising–Heisenberg diamond chain with a single-ion anisotropy

International Nuclear Information System (INIS)

Lisnyi, Bohdan; Strečka, Jozef

2015-01-01

The mixed spin-(1,1/2) Ising–Heisenberg diamond chain with a single-ion anisotropy is exactly solved through the generalized decoration–iteration transformation and the transfer-matrix method. The decoration–iteration transformation is first used for establishing a rigorous mapping equivalence with the corresponding spin-1 Blume–Emery–Griffiths chain, which is subsequently exactly treated within the transfer-matrix technique. Apart from three classical ground states the model exhibits three striking quantum ground states in which a singlet-dimer state of the interstitial Heisenberg spins is accompanied either with a frustrated state or a polarized state or a non-magnetic state of the nodal Ising spins. It is evidenced that two magnetization plateaus at zero and/or one-half of the saturation magnetization may appear in low-temperature magnetization curves. The specific heat may display remarkable temperature dependences with up to three and four distinct round maxima in a zero and non-zero magnetic field, respectively. - Highlights: • Mixed spin-(1,1/2) Ising–Heisenberg diamond chain is exactly solved. • Quantum ground states with a singlet-dimer state of the Heisenberg spins are found. • Magnetization curve displays intermediate plateaus at zero and half of full magnetization. • Thermal dependences of specific heat may display up to four distinct peaks

Gastrodia elata Blume extract ameliorates exercise- induced fatigue

African Journals Online (AJOL)

ONOS

2010-09-06

Sep 6, 2010 ... depletion of energy materials in the body. It is also related ... Gastrodia elata Blume (GEB) (Tianma in Chinese) is a traditional herbal plant. ... were adapted to diet for 1 week before the experiment began. 120 mice were ...

DAYA KECAMBAH BENIH ROTAN JERNANG (Daemonorops draco Blume DENGAN BERBAGAI PERLAKUAN PERENDAMAN DALAM AIR

Directory of Open Access Journals (Sweden)

Emmy Winarni

2018-01-01

Full Text Available Good germination of rattan seed (DaemonoropsdracoBlume will increase the germination rate, germination rate, and germination rate. However, to germinate undergoes any obstacles because the seed of jernangrattan has a period of dormancy. The immersion in cold water or at normal temperature (28o - 32o C is one way that can be used to break the dormancy period of the seed. This study aims to determine the long immersion to the value of germination of rattan seed jernang (D. dracoBlume. This study used 3 treatments and 1 replication. The treatment in this research is soaking time without immersion (control, soaking for 24 hours, and 48 hours. The result research is that the long immersion has the effect on germination of rattan seed jernang (D. dracoBlume. The results showed that the best percentage of rattan seed germination (D.dracoBlume got the preliminary treatment with water immersion for 24 hours with a percentage of 80%. The best seed germination rate is at 48 hours of water immersion treatment at 33.89% / day. The highest germination rate was found in seeds treated by water immersion for 48 hours with an average of 0.0122% / day. Keywords : germination capacity; rotan jernang Perkecambahan benih rotan jernang (Daemonorops draco Blume yang baik akan meningkatkan daya kecambah, laju perkecambahan,dan nilai perkecambahan. Namun demikian untuk mengecambahkan masih terdapat kendala, karena benih rotan jernang memiliki masa dormansi. Perendam dalam air dingin atau pada suhu normal (28o - 32o C merupakan salah satu cara yang dapat digunakan untuk mematahkan masa dormansi benih. Penelitian ini bertujuan untuk mengetahui lama perendaman terhadap nilai perkecambahan benih rotan jernang (D. draco Blume . Penelitian menggunakan 3 perlakuan dan 1 ulangan. Perlakuan pada penelitian ini adalah waktu perendaman yaitu tanpa perendaman (kontrol, perendaman selama 24 jam, dan 48 jam. Hasil penelitian yang didapat adalah lama perendaman berpengaruh terhadap

A new phenylpropanoid glycoside from Jasminum subtriplinerve Blume.

Science.gov (United States)

Huong, Nguyen Thi Hong; Cu, Nguyen Khac Quynh; Quy, Trinh Van; Zidorn, Christian; Ganzera, Markus; Stuppner, Hermann

2008-01-01

From the ethyl acetate extract of the aerial parts of Jasminum subtriplinerve Blume (Oleaceae), 6'-O-menthiafoloylverbascoside (1), rutin (2), isoverbascoside (4), isooleoverbascoside (6), apiosylverbascoside (7), astragalin (9), isoquercitrin (10), and verbascoside (11) were isolated. Their structures were elucidated by extensive MS and NMR spectroscopy. Amongst 6'-O-menthiafoloylverbascoside (1) is a new phenylpropanoid glycoside.

Griffith energy project final environmental impact statement

International Nuclear Information System (INIS)

1999-03-01

Griffith Energy Limited Liability Corporation (Griffith) proposes to construct and operate the Griffith Energy Project (Project), a natural gas-fired, combined cycle power plant, on private lands south of Kingman, Arizona. The Project would be a merchant plant which means that it is not owned by a utility and there is currently no long-term commitment or obligation by any utility to purchase the capacity and energy generated by the power plant. Griffith applied to interconnect its proposed power plant with the Western Area Power Administration's (Western) Pacific Northwest-Pacific Southwest Intertie and Parker-Davis transmission systems. Western, as a major transmission system owner, needs to provide access to its transmission system when it is requested by an eligible organization per existing policies, regulations and laws. The proposed interconnection would integrate the power generated by the Project into the regional transmission grid and would allow Griffith to supply its power to the competitive electric wholesale market. Based on the application, Western's proposed action is to enter into an interconnection and construction agreement with Griffith for the requested interconnections. The proposed action includes the power plant, water wells and transmission line, natural gas pipelines, new electrical transmission lines and a substation, upgrade of an existing transmission line, and access road to the power plant. Construction of segments of the transmission lines and a proposed natural gas pipeline also require a grant of right-of-way across Federal lands administered by the Bureau of Land Management. Public comments on the Draft EIS are addressed in the Final EIS, including addenda and modifications made as a result of the comments and/or new information

Griffith Energy Project Final Environmental Impact Statement

Energy Technology Data Exchange (ETDEWEB)

N/A

1999-04-02

Griffith Energy Limited Liability Corporation (Griffith) proposes to construct and operate the Griffith Energy Project (Project), a natural gas-fuel, combined cycle power plant, on private lands south of Kingman, Ariz. The Project would be a ''merchant plant'' which means that it is not owned by a utility and there is currently no long-term commitment or obligation by any utility to purchase the capacity and energy generated by the power plant. Griffith applied to interconnect its proposed power plant with the Western Area Power Administration's (Western) Pacific Northwest-Pacific Southwest Intertie and Parker-Davis transmission systems. Western, as a major transmission system owner, needs to provide access to its transmission system when it is requested by an eligible organization per existing policies, regulations and laws. The proposed interconnection would integrate the power generated by the Project into the regional transmission grid and would allow Griffith to supply its power to the competitive electric wholesale market. Based on the application, Western's proposed action is to enter into an interconnection and construction agreement with Griffith for the requested interconnections. The proposed action includes the power plant, water wells and transmission line, natural gas pipelines, new electrical transmission lines and a substation, upgrade of an existing transmission line, and access road to the power plant. Construction of segments of the transmission lines and a proposed natural gas pipeline also require a grant of right-of-way across Federal lands administered by the Bureau of Land Management. Public comments on the Draft EIS are addressed in the Final EIS, including addenda and modifications made as a result of the comments and/or new information.

Griffith energy project draft environmental impact statement

International Nuclear Information System (INIS)

1998-10-01

Griffith Energy Limited Liability Corporation (Griffith) proposes to construct and operate the Griffith Energy Project (Project), a natural gas-fired, combined cycle power plant, on private lands south of Kingman, Arizona. The Project would be a merchant plant which means that it is not owned by a utility and there is currently no long-term commitment or obligation by any utility to purchase the capacity and energy generated by the power plant. Griffith applied to interconnect its proposed power plant with the Western Area Power Administration's (Western) Pacific Northwest-Pacific Southwest Intertie and Parker-Davis transmission systems. Western, as a major transmission system owner, needs to provide access to its transmission system when it is requested by an eligible organization per existing policies, regulations and laws. The proposed interconnection would integrate the power generated by the Project into the regional transmission grid and would allow Griffith to supply its power to the competitive electric wholesale market. Based on the application, Western's proposed action is to enter into an interconnection and construction agreement with Griffith for the requested interconnections. The proposed action includes the power plant, water wells and transmission line, natural gas pipelines, new electrical transmission lines and a substation, upgrade of an existing transmission line, and access road to the power plant. The existing environmental resource conditions in the Project area and the potential impacts on the resources by the proposed action and alternatives are described. Construction of segments of the transmission lines and a proposed natural gas pipeline also require a grant of right-of-way across Federal lands administered by the Bureau of Land Management

Quantum Griffiths phase in CePd1-xRhx with x ∼ 0.8

International Nuclear Information System (INIS)

Brando, M; Westerkamp, T; Deppe, M; Geibel, C; Steglich, F; Gegenwart, P

2010-01-01

The magnetic field dependence of the magnetisation (M) and the temperature dependence of the ac susceptibility (χ' = dM/dH) of CePd 1-x Rh x single crystals with 0.80 ≤ x ≤ 0.86 are analysed within the frame of the quantum Griffiths phase scenario, which predicts M ∝ H λ and χ' ∝ T λ-1 with 0 ≤ λ ≤ 1. All M vs H and χ' vs T data follow the predicted power-law behaviour. The parameter λ, extracted from χ'(T), is very sensitive to the Rh content x and varies systematically with x from -0.1 to 0.4. The value of λ, derived from M(H) measurements on a CePdo 0.2 Rho 0.8 single crystal, seems to be rather constant, λ ∼ 0.2, in a broad range of temperatures between 0.05 and 2 K and fields up to about 10 T. All observed signatures and the λ values are thus compatible with the quantum Griffiths scenario.

Constrained dynamics of universally coupled massive spin 2-spin 0 gravities

International Nuclear Information System (INIS)

Pitts, J Brian

2006-01-01

The 2-parameter family of massive variants of Einsteins gravity (on a Minkowski background) found by Ogievetsky and Polubarinov by excluding lower spins can also be derived using universal coupling. A Dirac-Bergmann constrained dynamics analysis seems not to have been presented for these theories, the Freund-Maheshwari-Schonberg special case, or any other massive gravity beyond the linear level treated by Marzban, Whiting and van Dam. Here the Dirac-Bergmann apparatus is applied to these theories. A few remarks are made on the question of positive energy. Being bimetric, massive gravities have a causality puzzle, but it appears soluble by the introduction and judicious use of gauge freedom

Dynamic phase transitions and dynamic phase diagrams in the kinetic spin-5/2 Blume-Capel model in an oscillating external magnetic field: Effective-field theory and the Glauber-type stochastic dynamics approach

Energy Technology Data Exchange (ETDEWEB)

Ertas, Mehmet [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Keskin, Mustafa, E-mail: keskin@erciyes.edu.tr [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Deviren, Bayram [Department of Physics, Nevsehir University, 50300 Nevsehir (Turkey)

2012-04-15

Using an effective field theory with correlations, we study a kinetic spin-5/2 Blume-Capel model with bilinear exchange interaction and single-ion crystal field on a square lattice. The effective-field dynamic equation is derived by employing the Glauber transition rates. First, the phases in the kinetic system are obtained by solving this dynamic equation. Then, the thermal behavior of the dynamic magnetization, the hysteresis loop area and correlation are investigated in order to characterize the nature of the dynamic transitions and to obtain dynamic phase transition temperatures. Finally, we present the phase diagrams in two planes, namely (T/zJ, h{sub 0}/zJ) and (T/zJ, D/zJ), where T absolute temperature, h{sub 0}, the amplitude of the oscillating field, D, crystal field interaction or single-ion anisotropy constant and z denotes the nearest-neighbor sites of the central site. The phase diagrams exhibit four fundamental phases and ten mixed phases which are composed of binary, ternary and tetrad combination of fundamental phases, depending on the crystal field interaction parameter. Moreover, the phase diagrams contain a dynamic tricritical point (T), a double critical end point (B), a multicritical point (A) and zero-temperature critical point (Z). - Highlights: Black-Right-Pointing-Pointer The effective-field theory is used to study the kinetic spin-5/2 Ising Blume-Capel model. Black-Right-Pointing-Pointer Time variations of average order parameter have been studied to find phases in the system. Black-Right-Pointing-Pointer The dynamic magnetization, hysteresis loop area and correlation have been calculated. Black-Right-Pointing-Pointer The dynamic phase boundaries of the system depend on D/zJ. Black-Right-Pointing-Pointer The dynamic phase diagrams are presented in the (T/zJ, h{sub 0}/zJ) and (D/zJ, T/zJ) planes.

Comparison of Emery 3004 and 3006 characteristics with DOP for possible use in HEPA filter leak tests

Energy Technology Data Exchange (ETDEWEB)

Kovach, B.J.; Banks, E.M.; Kovacs, G. [Nuclear Consulting Services, Inc., Columbus, OH (United States)

1995-02-01

The particle size distribution, concentration, liquid to aerosol conversion rate and ignition properties of DOP, Emery 3004 and Emery 3006 aerosols generated by the NUCON Aerosol Generators Models SN-10 and DG-F were obtained. Results demonstrate the Emery products are acceptable replacements for DOP in performing leak testing of HEPA filters.

Mixed Spin-1/2 and Spin-5/2 Model by Renormalization Group Theory: Recursion Equations and Thermodynamic Study

Science.gov (United States)

Antari, A. El; Zahir, H.; Hasnaoui, A.; Hachem, N.; Alrajhi, A.; Madani, M.; Bouziani, M. El

2018-04-01

Using the renormalization group approximation, specifically the Migdal-Kadanoff technique, we investigate the Blume-Capel model with mixed spins S = 1/2 and S = 5/2 on d-dimensional hypercubic lattice. The flow in the parameter space of the Hamiltonian and the thermodynamic functions are determined. The phase diagram of this model is plotted in the (anisotropy, temperature) plane for both cases d = 2 and d = 3 in which the system exhibits the first and second order phase transitions and critical end-points. The associated fixed points are drawn up in a table, and by linearizing the transformation at the vicinity of these points, we determine the critical exponents for d = 2 and d = 3. We have also presented a variation of the free energy derivative at the vicinity of the first and second order transitions. Finally, this work is completed by a discussion and comparison with other approximation.

EMERIS: an advanced information system for a materials testing reactor

International Nuclear Information System (INIS)

Adorjan, F.; Buerger, L.; Lux, I.; Mesko, L.; Szabo, K.; Vegh, J.; Ivanov, V.V.; Mozhaev, A.A.; Yakovlev, V.V.

1990-06-01

The basic features of the Materials Testing Reactor of IAE, Moscow (MR) Information System (EMERIS) are outlined. The purpose of the system is to support reactor and experimental test loop operators by a flexible, fully computerized and user-friendly tool for the aquisition, analysis, archivation and presentation of data obtained during operation of the experimental facility. High availability of EMERIS services is ensured by redundant hardware and software components, and by automatic configuration procedure. A novel software feature of the system is the automatic Disturbance Analysis package, which is aimed to discover primary causes of irregularities occurred in the technology. (author) 2 refs.; 2 figs

CONSTRAINING THE SPIN-DOWN TIMESCALE OF THE WHITE DWARF PROGENITORS OF TYPE Ia SUPERNOVAE

International Nuclear Information System (INIS)

Meng, Xiangcun; Podsiadlowski, Philipp

2013-01-01

Justham and Di Stefano et al. proposed that the white dwarf progenitor of a Type Ia supernova (SN Ia) may have to spin down before it can explode. As the white dwarf spin-down timescale is not well known theoretically, here we try to constrain it empirically (within the framework of this spin-down model) for progenitor systems that contain a giant donor and for which circumbinary material has been detected after the explosion: we obtain an upper limit of a few 10 7 yr. Based on the study of Di Stefano and Kilic, this means that it is too early to rule out the existence of a surviving companion in SNR 0509–67.5

Griffith Observatory: Hollywood's Celestial Theater

Science.gov (United States)

Margolis, Emily A.; Dr. Stuart W. Leslie

2018-01-01

The Griffith Observatory, perched atop the Hollywood Hills, is perhaps the most recognizable observatory in the world. Since opening in 1935, this Los Angeles icon has brought millions of visitors closer to the heavens. Through an analysis of planning documentation, internal newsletters, media coverage, programming and exhibition design, I demonstrate how the Observatory’s Southern California location shaped its form and function. The astronomical community at nearby Mt. Wilson Observatory and Caltech informed the selection of instrumentation and programming, especially for presentations with the Observatory’s Zeiss Planetarium, the second installed in the United States. Meanwhile the Observatory staff called upon some of Hollywood’s best artists, model makers, and scriptwriters to translate the latest astronomical discoveries into spectacular audiovisual experiences, which were enhanced with Space Age technological displays on loan from Southern California’s aerospace companies. The influences of these three communities- professional astronomy, entertainment, and aerospace- persist today and continue to make Griffith Observatory one of the premiere sites of public astronomy in the country.

Emergence of Griffiths phase and glassy mixed phase in Sm0.5Ca0.5MnO3 nanomanganites

International Nuclear Information System (INIS)

Giri, S.K.; Yusuf, S.M.; Mukadam, M.D.; Nath, T.K.

2014-01-01

Graphical abstract: A detailed investigation on the effect of grain size on formation of Griffiths phase, and glassy mixed phase in CE-type antiferromagnetic Sm 0.5 Ca 0.5 MnO 3 manganite are carried out. A rigorous measurement of linear and non-linear ac magnetic susceptibilities, time dependent relaxation and aging phenomena in Sm 0.5 Ca 0.5 MnO 3 nanomanganite confirm the existence of a glassy mixed phase in the low temperature regime. The signature of Griffiths phase in nanosized manganite has been confirmed from the detailed ac and dc magnetization studies. The existence of Griffiths phase is verified through the anomalous behavior of the low field temperature dependent an inverse ac and dc magnetic susceptibility. Based on experimental results, the glassy phase of nanomanganites has been attributed to the phase separation effect and interaction between the ferromagnetic clusters. A phenomenological core/shell model has also been proposed based on the surface disorder to explain the observed Griffiths phase in these nanosized manganites. Fig. 1: (Left) The plot of inverse of ac susceptibility χ ac -1 measured at f = 1 Hz and H ac = 2 Oe as a function of temperature for S750 sample. Inset shows the same for S550 sample. (Right) A schematic of the proposed model to describe the magnetic state of the Sm 0.5 Ca 0.5 MnO 3 system at different average sizes. Highlights: • Effect of grain size on Griffiths phase and glassy mixed phase is discussed. • GP is confirmed by dc, linear and non-linear ac magnetization in nanomanganites. • Glassy mixed phase is discussed by time dependent relaxation and aging phenomena. • The existence of GP is verified through an inverse ac and dc magnetic susceptibility. • A phenomenological core/shell model has been proposed based on surface disorder. -- Abstract: A detailed investigation on the effect of grain size on formation of Griffiths phase (GP), and glassy mixed phase in CE-type antiferromagnetic Sm 0.5 Ca 0.5 MnO 3

Quantum phase transitions in random XY spin chains

International Nuclear Information System (INIS)

Bunder, J.E.; McKenzie, R.H.

2000-01-01

Full text: The XY spin chain in a transverse field is one of the simplest quantum spin models. It is a reasonable model for heavy fermion materials such as CeCu 6-x Au x . It has two quantum phase transitions: the Ising transition and the anisotropic transition. Quantum phase transitions occur at zero temperature. We are investigating what effect the introduction of randomness has on these quantum phase transitions. Disordered systems which undergo quantum phase transitions can exhibit new universality classes. The universality class of a phase transition is defined by the set of critical exponents. In a random system with quantum phase transitions we can observe Griffiths-McCoy singularities. Such singularities are observed in regions which have no long range order, so they are not classified as critical regions, yet they display phenomena normally associated with critical points, such as a diverging susceptibility. Griffiths-McCoy phases are due to rare regions with stronger than! average interactions and may be present far from the quantum critical point. We show how the random XY spin chain may be mapped onto a random Dirac equation. This allows us to calculate the density of states without making any approximations. From the density of states we can describe the conditions which should allow a Griffiths-McCoy phase. We find that for the Ising transition the dynamic critical exponent, z, is not universal. It is proportional to the disorder strength and inversely proportional to the energy gap, hence z becomes infinite at the critical point where the energy gap vanishes

Research Note Nutritional evaluation of Ficus thonningii Blume ...

African Journals Online (AJOL)

Research Note Nutritional evaluation of Ficus thonningii Blume leaves as ruminant livestock feed in the Ahferom district of Tigray, Ethiopia. ... Data on foliar nitrogen (N), phosphorus (P), potassium (K), dry matter (DM), crude protein (CP), digestible crude protein (DCP), ether extract (EE), crude fibre (CF), ash content and ...

Local persistence and blocking in the two-dimensional blume-capel model

OpenAIRE

Silva, Roberto da; Dahmen, S. R.

2004-01-01

In this paper we study the local persistence of the two-dimensional Blume-Capel Model by extending the concept of Glauber dynamics. We verify that for any value of the ratio alpha = D/J between anisotropy D and exchange J the persistence shows a power law behavior. In particular for alpha 0 (a ¹ 1) we observe the occurrence of blocking.

Strong-coupling behaviour of two t - J chains with interchain single-electron hopping

International Nuclear Information System (INIS)

Zhang Guangming; Feng Shiping; Yu Lu.

1994-01-01

Using the fermion-spin transformation to implement spin-charge separation of constrained electrons, a model of two t - J chains with interchain single-electron hopping is studied by abelian bosonization. After spin-charge decoupling the charge dynamics can be trivially solved, while the spin dynamics is determined by a strong-coupling fixed point where the correlation functions can be calculated explicitly. This is a generalization of the Luther-Emery line for two-coupled t - J chains. The interchain single-electron hopping changes the asymptotic behaviour of the interchain spin-spin correlation functions and the electron Green function, but their exponents are independent of the coupling strength. (author). 25 refs

Search of the Griffiths shield region

International Nuclear Information System (INIS)

Wei, I.C.; Scott, R.L.

1988-01-01

The van der Walls equation of state for binary mixtures has been used to determine the location and shape of the Griffiths shield region (where three tricritical lines intersect). If one takes the geometric means for a 12 , the arithmetic mean for b 12 , and the configurational free energy as ideal, the center of the Griffiths shield region is found only when the ratio of molecular sizes is infinite. When the Flory equation for the configurational free energy for mixtures of chain molecules is substituted for the ideal form, the results appear to be somewhat different. However, for all the cases studied, with systems which approach geometric mean behavior one finds the shield region only when the ratio of molecular size is very large and when the internal pressure of the small molecule is very much greater than that of the long-chain molecule

D. W. Griffith and the Warrior Ethos.

Science.gov (United States)

Quart, Leonard; Auster, Al

1989-01-01

Discusses D. W. Griffith's perceptions of war, his idealized vision of the South before and after the Civil War, and his racism as evidenced in the film, "The Birth of a Nation." Considers responses to and effects of the film. (DMM)

Distrofia muscular de Emery-Dreifuss: relato de caso Emery-Dreifuss muscular dystrophy: case report

Directory of Open Access Journals (Sweden)

Ana Lucila Moreira Carsten

2006-06-01

Full Text Available A distrofia muscular de Emery-Dreifuss é uma forma de distrofia muscular freqüentemente associada a contraturas articulares e defeitos de condução cardíaca, que pode ser causada pela deficiência da proteína emerina na membrana nuclear interna das fibras musculares. Descrevemos o caso de um homem de 19 anos com diminuição de força muscular, hipotrofia nas cinturas escapular e pélvica, disfagia, contraturas articulares em cotovelos e tornozelos, apresentando história familiar compatível com herança ligada ao cromossomo X. A investigação mostrou creatinaquinase sérica elevada, eletrocardiograma com bloqueio atrioventricular de primeiro grau e bloqueio de ramo direito, eletroneuromiografia normal, biópsia muscular com alterações miopáticas e a análise por imuno-histoquímica mostrou deficiência de emerina. São discutidas as manifestações clínicas e genéticas, alterações laboratoriais e eletroneuromiográficas, bem como, a importância do estudo do padrão de herança no aconselhamento genético destas famílias.The Emery-Dreifuss muscular dystrophy is a form of muscular dystrophy that frequently presents early contractures and cardiac conduction defects, caused by emerin deficiency in the inner nuclear membrane of the muscular fibers. A 19-years-old man it presented muscle weakness and hypotrophy in the proximal upper and lower limbs, dysphagia and early contractures in elbows and ankles, with familiar history compatible with X-linked inheritance form. The investigation showed increased serum creatinekinase levels electrocardiogram had a first degree atrioventricular block and right bundle branch block normal electromyography and nerve conduction study muscle biopsy disclosed myopathic characteristics and nuclear protein immunohystochemical analysis showed deficiency of emerin. The clinical and genetics manifestations, laboratorial and electromyography changes, as well as, the study of the pattern of inheritance for

1985 Maurice Ewing Medalist: K.O. Emery

Science.gov (United States)

Stevenson, Robert E.; Emery, K. O.

Kenneth O. Emery is the consummate scientist in his chosen field; inventive, curious, imaginative, a leader, a listener, a teacher, an iconoclast, and the inveterate producer, all carried out with ingenuity and a warm, humorous yet constant personality. He is the friend one always appreciates, who is ready with counsel for every idea, who can think through nearly any question, big or small, and provide the logical brackets in which your concept is comfortably enclosed. For all of us, he stands high as the exemplary marine geologist of our time.

Emery-Kivelson solution of the two-channel Kondo problem

Science.gov (United States)

Sengupta, Anirvan M.; Georges, Antoine

1994-04-01

We consider the two-channel Kondo model in the Emery-Kivelson approach, and calculate the total susceptibility enhancement due to the impurity χimp=χ-χbulk. We find that χimp exactly vanishes at the solvable point, in a completely analogous way to the singular part of the specific heat Cimp. A perturbative calculation around the solvable point yields the generic behavior χimp~log(1/T), Cimp~T logT and the known universal value of the Wilson ratio RW=8/3. From this calculation, the Kondo temperature can be identified and is found to behave as the inverse square of the perturbation parameter. The small-field, zero-temperature behavior χimp~log(1/h) is also recovered.

Ver o que aconteceu: Cinema e Histria em Griffith e Spielberg Regarding what happened: Cinema and History in Griffith and Spielberg

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Eduardo Victorio Morettin

2012-01-01

Full Text Available O objetivo deste texto discutir as conexes entre o discurso histrico e cinematogrfico, a partir das estratgias de autenticao em O Nascimento de uma Nao (The Birth of Nation, 1915, de David Griffith, e Amistad (1997, de Steven Spielberg. Sero examinadas as leituras que os filmes fazem da representao do tema da escravido e os vnculos com o contexto em que foram produzidos, analisando tambm as questes de estilo presentes nas duas obras.This text aims at discussing the connections between the historical and cinematographic discourse, starting from the authentication strategies employed by two films: The Birth of Nation (1915, from David Griffith, and Amistad (1997, from Steven Spielberg. This article will examine the different interpretations of the slavery theme and the link to the context in which they were produced, including the analysis of the style used on these two films.

Data analysis methods in physical oceanography. By Emery, W.J. and Thomson, R.E.

Digital Repository Service at National Institute of Oceanography (India)

Nayak, M.R.

in Physical Oceanography. Page 1 of 1 file://C:\\My Documents\\articles30.htm 2/11/05 William J. Emery and Richard E. Thomson. Pergamon Elsevier Science. 1998. hardbound. 400 pp. ISBN: 0-08-031434-1. Price: US$ 112/NLG 177.00 This book provides a comprehensive... and practical compilation of the essential information and analysis techniques required for the advanced processing and interpretation of digital spatio-temporal data in physical oceanography, as well as in other branches of the geophysical sciences. The book...

Electron spin resonance and quantum critical phenomena in VOx multiwall nanotubes

International Nuclear Information System (INIS)

Demishev, S.V.; Chernobrovkin, A.L.; Glushkov, V.V.; Samarin, N.A.; Sluchanko, N.E.; Semeno, A.V.; Goodilin, E.A.; Grigorieva, A.V.; Tretyakov, Yu.D.

2008-01-01

Basing on the high frequency (60 GHz) electron spin resonance study of the VO x multiwall nanotubes (VO x -NTs) carried out in the temperature range 4.2-200 K we report: (i) the first direct experimental evidence of the presence of the antiferromagnetic dimers in VO x -NTs and (ii) the observation of an anomalous low temperature growth of the magnetic susceptibility for quasi-free spins, which obey the power law χ(T)∝1/T α with the exponent α∼0.6 in a wide temperature range 4.2-50 K. We argue that the observed departures from the Curie-Weiss behaviour manifest the onset of the quantum critical regime and formation of the Griffiths phase as a magnetic ground state of these spin species. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Emery-Dreifuss muscular dystrophy: the most recognizable laminopathy

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Agnieszka Madej-Pilarczyk

2016-03-01

Full Text Available Emery-Dreifuss muscular dystrophy (EDMD, a rare inherited disease, is characterized clinically by humero-peroneal muscle atrophy and weakness, multijoint contractures, spine rigidity and cardiac insufficiency with conduction defects. There are at least six types of EDMD known so far, of which five have been associated with mutations in genes encoding nuclear proteins. The majority of the EDMD cases described so far are of the emerinopathy (EDMD1 kind, with a recessive X-linked mode of inheritance, or else laminopathy (EDMD2, with an autosomal dominant mode of inheritance. In the work described here, the authors have sought to describe the history by which EDMD came to be distinguished as a separate entity, as well as the clinical and genetic characteristics of the disease, the pathophysiology of lamin-related muscular diseases and, finally, therapeutic issues, prevention and ethical aspects.

Mixed spin-3/2 and spin-5/2 Ising system on the Bethe lattice

International Nuclear Information System (INIS)

Albayrak, Erhan; Yigit, Ali

2006-01-01

In order to study the critical behaviors of the half-integer mixed spin-3/2 and spin-5/2 Blume-Capel Ising ferrimagnetic system, we have used the exact recursion relations on the Bethe lattice. The system was studied for the coordination numbers with q=3, 4, 5 and 6, and the obtained phase diagrams are illustrated on the (kT c /|J|,D A /|J|) plane for constant values of D B /|J|, the reduced crystal field of the sublattice with spin-5/2, and on the (kT c /|J|,D B /|J|) plane for constant values of D A /|J|, the reduced crystal field of the sublattice with spin-3/2, for q=3 only, since the cases corresponding to q=4, 5 and 6 reproduce results similar to the case for q=3. In addition we have also presented the phase diagram with equal strengths of the crystal fields for q=3, 4, 5 and 6. Besides the second- and first-order phase transitions, the system also exhibits compensation temperatures for appropriate values of the crystal fields. In this mixed spin system while the second-order phase transition lines never cut the reduced crystal field axes as in the single spin type spin-3/2 and spin-5/2 Ising models separately, the first-order phase transition lines never connect to the second-order phase transition lines and they end at the critical points, therefore the system does not give any tricritical points. In addition to this, this mixed-spin model exhibits one or two compensation temperatures depending on the values of the crystal fields, as a result the compensation temperature lines show reentrant behavior

Constraining Δ G at Low-x with Double Longitudinal Spin Asymmetries for Forward Hadron and Di-Hadron Pairs in PHENIX

Science.gov (United States)

Wolin, Scott; Phenix Collaboration

2011-10-01

The gluon polarization, ΔG =∫01 g(x) dx , is constrained in the region 0 . 05 double spin asymmetries, ALL, for inclusive hadron and jet production at mid-rapidity at RHIC. Theoretical analysis of experimental results shows that ∫0. 05 0 . 2 Δg(x) dx = 0 .013-0 . 120 + 0 . 106 . This is not large enough to account for the missing proton spin. However, Δg(x) is unconstrained at low-x, and a measurement sensitive to this region will provide important input for future global analyses. The measurement of ALL for inclusive hadrons and di-hadrons with the Muon Piston Calorimeter (MPC) 3 . 1 < η < 3 . 9 provides this sensitivity down to x 10-3 and will lead to the first constraints of Δg(x) at x < 0 . 05 . The di-hadron measurement is especially interesting as it is sensitive to the sign of ΔG and best constrains the parton kinematics giving the most precise access to xgluon. The inclusive measurement provides a looser constraint on the event kinematics but has a higher yield. We will present the status of these measurements for the 2009 dataset at √{ s} = 500 GeV and √{ s} = 200 GeV.

Abnormal sympathetic innervation of the heart in a patient with Emery-Dreifuss muscular dystrophy.

Science.gov (United States)

Fujiita, Takashi; Shimizu, Masami; Kaku, Bunji; Kanaya, Hounin; Horita, Yuki; Uno, Yoshihide; Yamazaki, Tsukasa; Ohka, Takio; Sakata, Kenji; Mabuchi, Hiroshi

2005-07-01

A 33-year-old man was admitted for general malaise and vomiting. An electrocardiogram showed a complete atrioventricular block and an echocardiogram showed right atrial dilatation and normal wall motion of left ventricle (LV). Gene analysis showed nonsense mutation in the STA gene, which codes for emerin, and Emery-Dreifuss muscular dystrophy was diagnosed. An endomyocardial biopsy of right ventricle showed mild hypertrophy of myocytes. Myocardial scintigraphic studies with Tc-99m methoxyisobutylisonitrile (MIBI) and I-123-betamethyl-p-iodophenylpentadecanoic acid (BMIPP) scintigrams showed no abnormalities. In contrast, I-123 metaiodobenzylguanidine (MIBG) scintigrams showed a diffuse and severe decrease in accumulation of MIBG in the heart. Six months later, his LV wall motion on echocardiograms developed diffuse hypokinesis. These results suggest that the abnormality on I-123 MIBG myocardial scintigrams may predict LV dysfunction in Emery-Dreifuss muscular dystrophy.

Effects of rolling friction on a spinning coin or disk

Science.gov (United States)

Cross, Rod

2018-05-01

Experimental and theoretical results are presented concerning the motion of a spinning disk on a horizontal surface. The disk precesses about a vertical axis while falling either quickly or slowly onto the surface depending on the coefficient of rolling friction. The rate of fall also depends on the offset distance, in the rolling direction, between the centre of mass and the line of action of the normal reaction force. Euler’s angular momentum equations are solved to obtain estimates of both the coefficient of friction and the offset distance for a 50.6 mm diameter brass disk spinning on three different surfaces. The fall times varied from about 3 s on P800 emery paper to about 30 s on glass.

BIOACTIVITIES AND CHEMICAL CONSTITUENTS OF A VIETNAMESE MEDICINAL PLANT JASMINUM SUBTRIPLINERVE BLUME (CHE VANG )

OpenAIRE

Dai, Hue Ngan

2006-01-01

#This thesis encompasses two parts. The first part deals with general introduction to isolation, characterization, and bioactivities of natural products, with emphasis on Jasminum Subtriplinerve Blume spp., and its genus. The second is experimental study of J.subtriplinerve Bl. about its bioactivities and chemical constituents. In first part (from chapter 1 to 6), the botanical of two varieties of J.subtriplinerve Bl., a medicinal plant widely distributed in Middle area of Vietnam that has ju...

Distinct functional domains in nesprin-1α and nesprin-2β bind directly to emerin and both interactions are disrupted in X-linked Emery-Dreifuss muscular dystrophy

International Nuclear Information System (INIS)

Wheeler, Matthew A.; Davies, John D.; Zhang Qiuping; Emerson, Lindsay J.; Hunt, James; Shanahan, Catherine M.; Ellis, Juliet A.

2007-01-01

Emerin and specific isoforms of nesprin-1 and -2 are nuclear membrane proteins which are binding partners in multi-protein complexes spanning the nuclear envelope. We report here the characterisation of the residues both in emerin and in nesprin-1α and -2β which are involved in their interaction and show that emerin requires nesprin-1 or -2 to retain it at the nuclear membrane. Using several protein-protein interaction methods, we show that residues 368 to 627 of nesprin-1α and residues 126 to 219 of nesprin-2β, which show high homology to one another, both mediate binding to emerin residues 140-176. This region has previously been implicated in binding to F-actin, β-catenin and lamin A/C suggesting that it is critical for emerin function. Confirmation that these protein domains interact in vivo was shown using GFP-dominant negative assays. Exogenous expression of either of these nesprin fragments in mouse myoblast C2C12 cells displaced endogenous emerin from the nuclear envelope and reduced the targeting of newly synthesised emerin. Furthermore, we are the first to report that emerin mutations which give rise to X-linked Emery-Dreifuss muscular dystrophy, disrupt binding to both nesprin-1α and -2β isoforms, further indicating a role of nesprins in the pathology of Emery-Dreifuss muscular dystrophy

Comparative Aspects of Spin-Dependent Interaction Potentials for Spin-1/2 and Spin-1 Matter Fields

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P. C. Malta

2016-01-01

Full Text Available This paper sets out to establish a comparative study between classes of spin- and velocity-dependent potentials for spin-1/2 and spin-1 matter currents/sources in the nonrelativistic regime. Both (neutral massive scalar and vector particles are considered to mediate the interactions between (pseudo-scalar sources or (pseudo-vector currents. Though our discussion is more general, we contemplate specific cases in which our results may describe the electromagnetic interaction with a massive (Proca-type photon exchanged between two spin-1/2 or two spin-1 carriers. We highlight the similarities and peculiarities of the potentials for the two different types of charged matter and also focus our attention on the comparison between the particular aspects of two different field representations for spin-1 matter particles. We believe that our results may contribute to a further discussion of the relation between charge, spin, and extensibility of elementary particles.

Sb,123121 nuclear quadrupole resonance as a microscopic probe in the Te-doped correlated semimetal FeSb2: Emergence of electronic Griffith phase, magnetism, and metallic behavior

Science.gov (United States)

Gippius, A. A.; Zhurenko, S. V.; Hu, R.; Petrovic, C.; Baenitz, M.

2018-02-01

Sb,123121 nuclear quadrupole resonance (NQR) was applied to Fe(Sb1-xTex)2 in the low doping regime (x =0 , 0.01, and 0.05) as a microscopic zero field probe to study the evolution of 3 d magnetism and the emergence of metallic behavior. Whereas the NQR spectra itself reflects the degree of local disorder via the width of the individual NQR lines, the spin lattice relaxation rate (SLRR) 1 /T1(T ) probes the fluctuations at the Sb site. The fluctuations originate either from conduction electrons or from magnetic moments. In contrast to the semimetal FeSb2 with a clear signature of the charge and spin gap formation in 1 /T1(T ) T [˜exp/(Δ kBT ) ] , the 1% Te-doped system exhibits almost metallic conductivity and the SLRR nicely confirms that the gap is almost filled. A weak divergence of the SLRR coefficient 1 /T1(T ) T ˜T-n˜T-0.2 points towards the presence of electronic correlations towards low temperatures. This is supported by the electronic specific heat coefficient γ =(Cel/T ) showing a power-law divergence γ (T ) ˜T-m˜(1/T1T ) 1 /2˜T-n /2˜Cel/T which is expected in the renormalized Landau Fermi liquid theory for correlated electrons. In contrast to that the 5% Te-doped sample exhibits a much larger divergence in the SLRR coefficient showing 1 /T1(T ) T ˜T-0.72 . According to the specific heat divergence a power law with n =2 m =0.56 is expected for the SLRR. This dissimilarity originates from admixed critical magnetic fluctuations in the vicinity of antiferromagnetic long range order with 1 /T1(T ) T ˜T-3 /4 behavior. Furthermore Te-doped FeSb2 as a disordered paramagnetic metal might be a platform for the electronic Griffith phase scenario. NQR evidences a substantial asymmetric broadening of the Sb,123121 NQR spectrum for the 5% sample. This has a predominant electronic origin in agreement with the electronic Griffith phase and stems probably from an enhanced Sb-Te bond polarization and electronic density shift towards the Te atom inside Sb

Taxonomy of the African army ant Dorylus gribodoi Emery, 1892 (Hymenoptera, Formicidae) - new insights from DNA sequence data and morphology

DEFF Research Database (Denmark)

Schöning, Caspar; Gotwald, William H.; Kronauer, Daniel Jan Christoph

2008-01-01

Numerous species in the Old World army ant genus Dorylus have been described based on a single sex or caste. Our analysis of mitochondrial cytochrome oxidase II gene sequences of specimens from the same population reveals that D. gribodoi Emery males are conspecific with D. gerstaeckeri Emery...... a nest in Ivory Coast, is provided. Dorylus gerstaeckeri st. quadratus Santschi is shown to be distinct from D. gribodoi and synonymised under Dorylus kohli Wasmann. Similar studies examining the relationship between species described based on males and others described based on workers are needed...

The Effects of Davallic Acid from Davallia divaricata Blume on Apoptosis Induction in A549 Lung Cancer Cells

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Tsu-Liang Chang

2012-11-01

Full Text Available Traditional or folk medicinal herbs continue to be prescribed in the treatment of various diseases and conditions in many cultures. Recent scientific efforts have focused on the potential roles of extracts of traditional herbs as alternative and complementary medications for cancer treatment. In Taiwan, Davallia divaricata Blume has been traditionally employed in folk medicine for therapy of lung cancer, davallic acid being the major active compound of D. divaricata Blume. In this study, we investigated the inhibitory activity of davallic acid on the proliferation of A549 lung cancer cells. Davallic acid was extracted from D. divaricata Blume, and its effects on cell viability, cell cycle distribution, ROS level, and apoptotic protein expression in A549 cells were determined. Davallic acid significantly induced reactive oxygen species (ROS generation as well as caspase-3, -8, and -9 activation, thereby repressing A549 cell growth and elevating apoptotic activity. Since lung cancer has a high incidence of recurrence, these results indicate that davallic acid may have the potential to be a natural anti-lung cancer compound, and may provide a basis for further study of its use in combating cancer.

On the minima of the time integrated perturbation factor in the Scherer-Blume theory

International Nuclear Information System (INIS)

Silveira, E.F. da; Freire Junior, F.L.; Massolo, C.P.; Schaposnik, F.A.

1981-09-01

The minima in the correlation time dependence of the Scherer-Blume time integrated attenuation coefficients for the hyperfine perturbation of ions recoiling in gas are studied. Its position and depth are determined for different physical situations and comparison with experimental data is shown. (Author) [pt

LipSpin: A New Bioinformatics Tool for Quantitative 1H NMR Lipid Profiling.

Science.gov (United States)

Barrilero, Rubén; Gil, Miriam; Amigó, Núria; Dias, Cintia B; Wood, Lisa G; Garg, Manohar L; Ribalta, Josep; Heras, Mercedes; Vinaixa, Maria; Correig, Xavier

2018-02-06

The structural similarity among lipid species and the low sensitivity and spectral resolution of nuclear magnetic resonance (NMR) have traditionally hampered the routine use of 1 H NMR lipid profiling of complex biological samples in metabolomics, which remains mostly manual and lacks freely available bioinformatics tools. However, 1 H NMR lipid profiling provides fast quantitative screening of major lipid classes (fatty acids, glycerolipids, phospholipids, and sterols) and some individual species and has been used in several clinical and nutritional studies, leading to improved risk prediction models. In this Article, we present LipSpin, a free and open-source bioinformatics tool for quantitative 1 H NMR lipid profiling. LipSpin implements a constrained line shape fitting algorithm based on voigt profiles and spectral templates from spectra of lipid standards, which automates the analysis of severely overlapped spectral regions and lipid signals with complex coupling patterns. LipSpin provides the most detailed quantification of fatty acid families and choline phospholipids in serum lipid samples by 1 H NMR to date. Moreover, analytical and clinical results using LipSpin quantifications conform with other techniques commonly used for lipid analysis.

Bioactivities and chemical constituents of a vietnamese medicinal plant Che Vang, Jasminum subtriplinerve Blume (Oleaceae)

DEFF Research Database (Denmark)

Dai Hue, Ngan; Thi Cam, Hoai; Le Mai, Huong

2008-01-01

Five crude extracts were made from leaves and stems of Jasminum subtriplinerve Blume (Oleaceae) and investigated for antimicrobial, antioxidant and cytotoxic activities. The extractions were done with petroleum ether, ethyl acetate, ethanol, methanol or water. All extracts exhibited anti-bacteria...

ANATOMY OF GYNURA AURANTIACA (BLUME) SCH.BIP. EX DC. (ASTERACEAE)

OpenAIRE

Rodica BERCU

2014-01-01

The paper presents a detailed histoanatomical description, of the vegetative organs (root, stem and leaf) and photographs as well of Gynura aurantiaca (Blume) Sch.Bip. ex DC. It was observed that the root have typical primary dictos structure. The stem has a differentiated in two regions cortex and the stele comprise one ring of open collateral vascular bundles with secondary xylem due to the cambium activity. The petiole anatomy is quite similar in its basic structure with the stem. The blad...

Ischemic Stroke Due to Cardiac Involvement: Emery Dreifuss Patient

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Ersin Kasım Ulusoy

2015-08-01

Full Text Available Emery-Dreifuss muscular dystrophy (EDMD is a hereditary disease. It is characterized by early-onset contractures, slowly progressive weakness, fatigue related to skapulo-humero-peroneal muscle weakness, cardiomyopathy which develops in adulthood and cardiac conduction system block. Cardiac involvement has a prognostic significance in patients with EDMD and even sudden cardiac death may be the first clinical presentation. In this article, an EDMD patient with ischemic stroke clinic who didn’t have regular cardiac follow-up was reported and the importance of the treatment of cardiac diseases which could play a role in ischemic stroke etiology and the implantation of pace-maker was mentioned.

D. W. Griffith's Controversial Film, "The Birth of a Nation."

Science.gov (United States)

Pitcher, Conrad

1999-01-01

Presents a lesson plan that enables students to investigate race relations during the Progressive Era by analyzing D. W. Griffith's "The Birth of a Nation" and the controversy surrounding the release of the film. Explores the pros and cons of using motion pictures as teaching tool. Includes two student handouts. (CMK)

A Monte Carlo algorithm for sampling rare events: application to a search for the Griffiths singularity

International Nuclear Information System (INIS)

Hukushima, K; Iba, Y

2008-01-01

We develop a recently proposed importance-sampling Monte Carlo algorithm for sampling rare events and quenched variables in random disordered systems. We apply it to a two dimensional bond-diluted Ising model and study the Griffiths singularity which is considered to be due to the existence of rare large clusters. It is found that the distribution of the inverse susceptibility has an exponential tail down to the origin which is considered the consequence of the Griffiths singularity

Fe-doping induced Griffiths-like phase in La0.7Ba0.3CoO3

International Nuclear Information System (INIS)

Wan-Guo, Huang; Xiang-Qun, Zhang; Guo-Ke, Li; Young, Sun; Qing-An, Li; Zhao-Hua, Cheng

2009-01-01

The effect of Fe-doping on the magnetic properties of the ABO 3 -type perovskite cobaltites La 0.7 Ba 0.3 Co 1–y Fe y O 3 (0 ≤ y ≤ 0.80) is reported. With no apparent structural change in any doped sample, the Curie temperature (T C ) and the magnetization (M) are greatly suppressed for y ≤ 0.30 samples, while a distinct increase in T C for the y = 0.40 sample is observed. With the further increase of Fe concentration, T C increases monotonically. Griffiths-like phases in 0.40 ≤ y ≤ 0.60 samples are confirmed. The formation of the Griffiths-like phase is ascribed to B-site disordering induced isolation of ferromagnetic (FM) clusters above T C . (condensed matter: electronic structure, electrical, magnetic, and optical properties)

M-theory on eight-manifolds revisited: N = 1 supersymmetry and generalized Spin(7) structures

International Nuclear Information System (INIS)

Tsimpis, Dimitrios

2006-01-01

The requirement of N = 1 supersymmetry for M-theory backgrounds of the form of a warped product M x w X, where X is an eight-manifold and M is three-dimensional Minkowski or AdS space, implies the existence of a nowhere-vanishing Majorana spinor ξ on X. ξ lifts to a nowhere-vanishing spinor on the auxiliary nine-manifold Y: = X x S 1 , where S 1 is a circle of constant radius, implying the reduction of the structure group of Y to Spin(7). In general, however, there is no reduction of the structure group of X itself. This situation can be described in the language of generalized Spin(7) structures, defined in terms of certain spinors of Spin(TY+T*Y). We express the condition for N = 1 supersymmetry in terms of differential equations for these spinors. In an equivalent formulation, working locally in the vicinity of any point in X in terms of a 'preferred' Spin(7) structure, we show that the requirement of N = 1 supersymmetry amounts to solving for the intrinsic torsion and all irreducible flux components, except for the one lying in the 27 of Spin(7), in terms of the warp factor and a one-form L on X (not necessarily nowhere-vanishing) constructed as a ξ bilinear; in addition, L is constrained to satisfy a pair of differential equations. The formalism based on the group Spin(7) is the most suitable language in which to describe supersymmetric compactifications on eight-manifolds of Spin(7) structure, and/or small-flux perturbations around supersymmetric compactifications on manifolds of Spin(7) holonomy

Chemical Constituents from the Lianas of Gnetum cuspidatum Blume

International Nuclear Information System (INIS)

Nik Fatini Nik Azmin; Norizan Ahmat; Nik Khairunissa Nik Abdullah Zawawi; Norizan Ahmat; Nik Khairunissa Nik Abdullah Zawawi

2016-01-01

Gnetum is a genus of gymnosperms, the sole genus in the family Gnetaceae with approximately 40 species. Various species has been used for the treatment of rheumatitis, arthritis, bronchitis and asthma in folk medicines. Gnetum cuspidatum Blume is known throughout tropical Southeast Asia from Thailand, Vietnam, Cambodia, Malaysia, Sumatra, Java, and Borneo to the Maluku, Sulawesi and New Guinea. In this research work, a methanol extract of the lianas of Gnetum cuspidatum was subjected to vacuum liquid chromatography for fractionation. Later, several selective fractions had undergone the repetitive radial chromatography technique for further purification. Four known constituents categorized as stilbene type of compound have been successfully isolated and identified which include resveratrol (1), gnetucleistol C (2), gnetucleistol D (3) and gnemonol M (4). The structures and configuration of the reported compounds were elucidated on the basis of 2D-NMR correlations and comparison with the literature. (author)

Bioactivity of Indonesian mahogany, Toona sureni (Blume (Meliaceae, against the red flour beetle, Tribolium castaneum (Coleoptera, Tenebrionidae Bioatividade do mogno da Indonésia, Toona sureni (Blume (Meliaceae, contra o besouro-das-farinhas, Tribolium castaneum (Coleoptera, Tenebrionidae

Directory of Open Access Journals (Sweden)

Sahana Parvin

2012-09-01

Full Text Available Bioactivity of Indonesian mahogany, Toona sureni (Blume (Meliaceae, against the red flour beetle, Tribolium castaneum (Coleoptera, Tenebrionidae. The insecticidal activity of Toona sureni (Blume Merr. was evaluated considering repellency, mortality and progeny production of F1 adults of Tribolium castaneum (Herbst, 1797 (Coleoptera, Tenebrionidae. Dried extract of seeds of T. sureni was dissolved in acetone to prepare solution of various concentrations (0.5, 1.0, 2.5 and 5.0%. To test for repellency, the insects were exposed to treated filter paper. Mortality of larvae, pupae and adults was evaluated by the treatment of spraying the insects with different concentrations of T. sureni extract. Residual effect of the extract was also evaluated considering the production of progeny of F1 adults. The highest repellency (93.30% of T. castaneum occurred at the highest concentration (5.0% suspension of T. sureni; while the lowest (0.0% repellency occurred at 0.5% suspension after 1 day of treatment. The highest mortality against adults (86.71%, larvae (88.32% and pupae (85% occurred at 5% suspension at 8 days after application. There was a negative correlation between the concentrations of T. sureni and the production of F1 adult's progeny of T. castaneum. The highest number of progeny (147 of T. castaneum occurred in the control at 7 days after treatment; and the lowest number of progeny (43 occurred at 5.0% concentration in 1 day after treatment. The results show that T. sureni is toxic to T. castaneum and has the potential to control all stages of this insect in stored wheat.Bioatividade do mogno da Indonésia, Toona sureni (Blume (Meliaceae, contra o besouro-das-farinhas, Tribolium castaneum (Coleoptera, Tenebrionidae. A atividade inseticida de Toona sureni (Blume Merr. foi avaliada considerando repelência, mortalidade e a produção de progênie de adultos F1 de Tribolium castaneum (Herbst, 1797 (Coleoptera, Tenebrionidae. Extrato seco de sementes

Effects of disorder on atomic density waves and spin-singlet dimers in one-dimensional optical lattices

International Nuclear Information System (INIS)

Gao Xianlong

2008-01-01

Using the Bethe-ansatz density-functional theory, we study a one-dimensional Hubbard model of confined attractively interacting fermions in the presence of a uniformly distributed disorder. The strongly correlated Luther-Emery nature of the attractive one-dimensional Hubbard model is fully taken into account as the reference system in the density-functional theory. The effects of the disorder are investigated on the atomic density waves in the weak-to-intermediate attractive interaction and on the spin-singlet dimers of doubly occupied sites in the strongly attractive regime. It is found that atomic density waves are sensitive to the disorder and the spin-singlet dimers of doubly occupied sites are quite unstable against the disorder. We also show that a very weak disorder could smear the singularities in the stiffness, thus, suppresses the spin-singlet pairs

Caracterização de ninhos e atividade forrageadora de Trachymyrmex fuscus Emery (Hymenoptera, Formicidae em plantio de eucalipto Caracterization of nest and foraging activity of Trachymyrmex fuscus Emery (Hymenoptera, Formicidae in Eucalyptus stand

Directory of Open Access Journals (Sweden)

Márcio Silva Araújo

2002-06-01

Full Text Available Seven nests of T. fuscus Emery, 1834 have been studied for their structure. These nests, which opened at the soil surface, had two to four chambers located one above the other. Externally all of these nests presented a heap of brownish-yellow debris that was constituted basically by remains of vegetable material. The total nest population was, on average, 1,048 individuais. The diel pattern of foraging of this species was studied for four consecuti ve months on two nests. This activity occurred predominantly in the night period, and the workers transported, mainly, dry vegetation to the nest.

Electron-Spin Filters Would Offer Spin Polarization Greater than 1

Science.gov (United States)

Ting, David Z.

2009-01-01

A proposal has been made to develop devices that would generate spin-polarized electron currents characterized by polarization ratios having magnitudes in excess of 1. Heretofore, such devices (denoted, variously, as spin injectors, spin polarizers, and spin filters) have typically offered polarization ratios having magnitudes in the approximate range of 0.01 to 0.1. The proposed devices could be useful as efficient sources of spin-polarized electron currents for research on spintronics and development of practical spintronic devices.

Research in the School of Languages and Linguistics at Griffith University

Science.gov (United States)

Fenton-Smith, Ben; Walkinshaw, Ian

2014-01-01

Griffith University is set across five campuses in south-east Queensland, Australia, and has a student population of 43,000. The School of Languages and Linguistics (LAL) offers programs in linguistics, international English, Chinese, Italian, Japanese and Spanish, as well as English language enhancement courses. Research strands reflect the…

Ecologia do forrageio por Cyphomyrmex morschi Emery (Hymenoptera, Formicidae em vegetação de restinga no Sul do Brasil Foraging ecology of Cyphomyrmex morschi Emery (Hymenoptera, Formicidae in sand dune vegetation at Southern Brazil

Directory of Open Access Journals (Sweden)

Benedito Cortês Lopes

2007-03-01

Full Text Available Foram amostrados 400 ninhos de Cyphomyrmex morschi Emery, 1887 entre 1997 e 1998, nas dunas da praia da Joaquina, Florianópolis, SC, para a verificação do material transportado ao ninho. Estas formigas utilizam material de origem vegetal ou animal (fezes de lagartas de Lepidoptera ou partes de corpos de besouros ou formigas ou mesmo material não identificado que são introduzidos no ninho para o cultivo do fungo. Assim, do ponto de vista do papel ecológico desempenhado, pode-se considerar C. morschi como uma espécie detritófaga.A total of 400 nests of Cyphomyrmex morschi Emery, 1887 was evaluated between 1997 and 1998 at the dunes of the Joaquina Beach, Florianópolis, Santa Catarina, in order to verify the substrate brought back to the nests. These ants use vegetable or animal material (excrements of lepidopteran larvae or carcasses of beetles or ants or even not identified material that are used to culture the fungus. Thus, ecologically speaking, C. morschi can be considered a detritiphagous species.

Observation of a Griffiths-like Phase in the Magnetocaloric Compound Tb5Si2Ge2

International Nuclear Information System (INIS)

Magen, C.; Algarabel, P.A.; Morellon, L.; Ibarra, M.R.; Araujo, J.P.; Pereira, A.M.; Sousa, J.B.; Ritter, C.

2006-01-01

The onset of a Griffiths-like phase has been observed in Tb 5 Si 2 Ge 2 (T C =110 K) by means of magnetic susceptibility and small-angle neutron scattering experiments. We show the growth of a ferromagnetic cluster system characterized by an inverse susceptibility exponent lower than unity at T C G ≅200 K. We suggest that the Griffiths-like state is originated by local disorder within the crystallographic structure, stabilized and enhanced by competing intralayer and interlayer magnetic interactions. Both factors thus promote segregation of nanometric regions with ferromagnetic interactions

Final COMPASS results on the spin-dependent structure functions $g_1^p$ and $g_1^d$ in the deep-inelastic and nonperturbative regions

CERN Document Server

Badelek, Barbara

2018-01-01

This paper summarizes the COMPASS Collaboration legacy on measurements of the proton and deuteron spin-dependent structure functions, $g_1^p$ and $g_1^d$ at $Q^2 1$ (GeV/c)$^2$. In both regions and at the lowest measured $x, g^d_1 (x)$ is consistent with zero while $g^p_1 (x)$ is positive. This is the first time that the spin effects are observed at such low values of $x$. The NLO QCD fit of $g_1$ world data gives well constrained quark helicity distributions; gluons are poorly determined. Quark helicity contribution to nucleon spin is $0.26 < \\Delta \\Sigma < 0.36$. From the COMPASS data alone the Bjorken sum rule is verified to $9\\%$ accuracy and the extracted flavour-singlet axial charge is $a_0 (Q^2 = 3 (\\text{GeV/}c)^2) = 0.32 \\pm 0.02_{stat.} \\pm 0.04_{syst.} \\pm 0.05_{evol.}$.

Final COMPASS results on the spin-dependent structure functions $g_1^p$ and $g_1^d$ in the deep-inelastic and nonperturbative regions

CERN Document Server

Badelek, Barbara

2017-01-01

This paper summarizes the COMPASS Collaboration legacy on measurements of the proton and deuteron spin-dependent structure functions, $g_1^p$ and $g_1^d$ at $Q^2 1$ (GeV/c)$^2$. In both regions and at the lowest measured $x, g^d_1 (x)$ is consistent with zero while $g^p_1 (x)$ is positive. This is the first time that the spin effects are observed at such low values of $x$. The NLO QCD fit of $g_1$ world data gives well constrained quark helicity distributions; gluons are poorly determined. Quark helicity contribution to nucleon spin is $0.26 < \\Delta \\Sigma < 0.36$. From the COMPASS data alone the Bjorken sum rule is verified to $9\\%$ accuracy and the extracted flavour-singlet axial charge is $a_0 (Q^2 = 3 (\\text{GeV/}c)^2) = 0.32 \\pm 0.02_{stat.} \\pm 0.04_{syst.} \\pm 0.05_{evol.}$.

Bioactivity of Indonesian mahogany, Toona sureni (Blume (Meliaceae, against the red flour beetle, Tribolium castaneum (Coleoptera, Tenebrionidae

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Sahana Parvin

2012-09-01

Full Text Available Bioactivity of Indonesian mahogany, Toona sureni (Blume (Meliaceae, against the red flour beetle, Tribolium castaneum (Coleoptera, Tenebrionidae. The insecticidal activity of Toona sureni (Blume Merr. was evaluated considering repellency, mortality and progeny production of F1 adults of Tribolium castaneum (Herbst, 1797 (Coleoptera, Tenebrionidae. Dried extract of seeds of T. sureni was dissolved in acetone to prepare solution of various concentrations (0.5, 1.0, 2.5 and 5.0%. To test for repellency, the insects were exposed to treated filter paper. Mortality of larvae, pupae and adults was evaluated by the treatment of spraying the insects with different concentrations of T. sureni extract. Residual effect of the extract was also evaluated considering the production of progeny of F1 adults. The highest repellency (93.30% of T. castaneum occurred at the highest concentration (5.0% suspension of T. sureni; while the lowest (0.0% repellency occurred at 0.5% suspension after 1 day of treatment. The highest mortality against adults (86.71%, larvae (88.32% and pupae (85% occurred at 5% suspension at 8 days after application. There was a negative correlation between the concentrations of T. sureni and the production of F1 adult's progeny of T. castaneum. The highest number of progeny (147 of T. castaneum occurred in the control at 7 days after treatment; and the lowest number of progeny (43 occurred at 5.0% concentration in 1 day after treatment. The results show that T. sureni is toxic to T. castaneum and has the potential to control all stages of this insect in stored wheat.

Off-criticality behaviour of the Blume-Capel quantum chain as a check of Zamolodchikov's conjecture

International Nuclear Information System (INIS)

Gehlen, G. v.

1989-07-01

Using finite-size numerical calculations, we study the off-criticality behaviour of the Blume-Capel quantum chain in the neighbourhood of the c=7/10 tricritical Ising point. Moving from the tricritical point in the (1/10, 1/10)- and (3/5, 3/5)-directions into the disordered region, we find masses and thresholds in agreement with the structure proposed by Zamolodchikov from conformal field theory. Moving in the opposite directions, the spectrum is degenerate between the Z 2 -even and Z 2 -odd sectors, suggesting an underlying supersymmetry. The free-particle energy momentum relation and the scaling properties off criticality are checked. (orig.)

Uji Penghambatan Aktivitas Alfa-glukosidase Ekstrak Dan Fraksi Daun Antidesma Montanum Blume

OpenAIRE

Nofiantini,; Elya, Berna; Azizahwati,

2012-01-01

Alpha-Glucosidase inhibitor has known to be a therapeutic agent for diabetes mellitus (DM) treatment, especially type 2 DM. Based on previous studies. There are various plants that have the effect of inhibiting the activity of a-glucosidase, one of which is garu leaves (Antidesma montanum Blume). This research aimed to get the fraction which had the highest Il-glucosidase inhibiting activity from ethanol extract of garu leaves and identify the chemical compounds from the most active fraction....

Emery-Dreifuss muscular dystrophy: anatomical-clinical correlation (case report Distrofia muscular de Emery-Dreifuss: correlação anátomo-clínica (relato de caso

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ALZIRA ALVES DE SIQUEIRA CARVALHO

2000-12-01

Full Text Available We report on a man that had weakness of humeroperoneal distribution associated with limited range of motion of the cervical spine and elbows since he was 5 years old . At age 26 he developed tachycardia episodes. A complex arrhythmia was discovered, and a nodal ablation was done with a cardiac pacemaker implanted. The patient had an arrhythmia and sudden death followed this. Emery-Dreifuss muscular dystrophy is a rare recessive X-linked muscular disorder where mixed patterns in electromyography and muscle histology (neurogenic and/or myopathic have caused nosological confusion. The autopsy findings are here described and correlated to the clinical features in an attempt to better understand the ambiguous findings concerning the process etiology .Relatamos o caso de um paciente com fraqueza muscular de distribuição úmero-peroneal associada a limitação de movimentos da coluna cervical e cotovelos. Aos 26 anos, ele desenvolveu episódios de taquicardia. Uma arritmia complexa foi descoberta sendo feito ablação nodal seguida por implante de marcapasso cardíaco. O paciente evoluiu com arritmia e morte. A distrofia de Emery-Dreifuss é desordem muscular rara, recessiva, ligada ao cromossomo X cujo aspectos mistos (neurogênico e/ou miopático na eletroneuromiografia e biopsia muscular tem provocado dúvidas na nosologia. Os achados de autopsia são descritos e correlacionados aos critérios clínicos na tentativa de melhor compreender os achados ambíguos em relação à etiologia.

Observation of Griffiths-like phase and its tunability in La{sub 2}Ni{sub 1−x}Co{sub x}MnO{sub 6} (0≤x≤1) nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Krishna Murthy, J., E-mail: krishna.jk1@gmail.com [Cryogenic Engineering Centre, Indian Institute of Technology, Kharagpur 721302 (India); Department of Physics, Indian Institute of Science, Banglore 560012 (India); Devi Chandrasekhar, K. [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Venimadhav, A. [Cryogenic Engineering Centre, Indian Institute of Technology, Kharagpur 721302 (India)

2016-11-15

Temperature and magnetic field dependent magnetic properties of La{sub 2}Ni{sub 1−x}Co{sub x}MnO{sub 6} (0≤x≤ 1) nanoparticles prepared by sol–gel method with average particle size ∼25–60 nm have been investigated. X-ray diffraction and Raman spectra study have revealed the suppression of structural disorder with the increase of Co content. Magnetic ordering and magnetization properties like, transition temperature (T{sub C}), coercive field (H{sub C}) and spontaneous magnetization (M{sub S}) increases with the Co substitution at the Ni site. The inverse magnetic susceptibility above T{sub C} has shown a broad temperature regime with a downward deviation from the Curie–Weiss law, a characteristic feature of Griffiths-like phase. This temperature regime of magnetic inhomogeneity decreases with the increase of Co content and completely absent for La{sub 2}CoMnO{sub 6}. - Highlights: • The Reviewer's comments and suggestions are very good which will be more useful to which have strengthened the paper. • Regarding the Reviewer 2 comment about magnetic field dependent Griffith's phase is good. And we have done this measurement to check the GP at higher fields. • With this standard review and Editor comments, we tried to improve the paper quality.

Revisionary notes on the fungus-growing ant genus Mycetarotes Emery (Hymenoptera, Formicidae Notas sobre as formigas cultivadoras de fungos do gênero Mycetarotes Emery (Hymenoptera, Formicidae

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Antonio José Mayhé-Nunes

2006-12-01

Full Text Available Mycetarotes is a small genus of the exclusively Neotropical fungus-growing ants, that includes M. parallelus (Emery, M. senticosus Kempf, M. acutus Mayhé-Nunes and M. carinatus Mayhé-Nunes. We hereby revise historical and recent information regarding Mycetarotes species for the first time, providing an identification key to workers, diagnoses, synoptic illustrated redescriptions of the species, including those of sexuals when known, updates of distributional records, and nest pictures of M. carinatus and M. parallelus. We comment the taxonomy and phylogenetic relationships among Mycetarotes and related genera, and on their geographical distribution. The available biological information on the genus is summarized.O gênero Mycetarotes inclui quatro espécies de formigas cultivadoras de fungos, exclusivamente encontradas na região Neotropical: M. parallelus (Emery, M. senticosus Kempf, M. acutus Mayhé-Nunes and M. carinatus Mayhé-Nunes. Apresentamos pela primeira vez um resumo sobre as informações disponíveis para as espécies do gênero, fornecendo uma chave para a identificação das operárias, diagnoses e redescrições sinópticas ilustradas das espécies, incluindo as dos alados, quando conhecidos, atualização dos registros de distribuição e fotografias dos ninhos de M. carinatus e M. parallelus. Comentamos a taxonomia e as relações de parentesco entre Mycetarotes e gêneros cognatos, e sobre sua distribuição geográfica. As informações biológicas disponíveis sobre o gênero também foram resumidas.

Application of the Scherer-Blume theory to the intermediate ionization regime

International Nuclear Information System (INIS)

Zemel, A.; Niv, Y.

1977-01-01

Blume's formula for the time-differential attenuation coefficients for the hyperfine perturbation of ions recoiling in gas is rewritten in a form convenient for numerical solution when the number of precession frequencies is large. Asymptotic expressions for the behaviour of the solutions for very short, and very long correlation time are given. Approximate condition for the existence of a minimum in the pressure dependence of the time differential coefficients, as well as the position and depth of such a minimum, are also derived, and compared with the results of calculations for various physical systems. (Auth.)

Extracts and compounds with anti-diabetic complications and anti-cancer activity from Castanea mollissina Blume (Chinese chestnut).

Science.gov (United States)

Zhang, Lin; Gao, Hui-yuan; Baba, Masaki; Okada, Yoshihito; Okuyama, Toru; Wu, Li-jun; Zhan, Li-bin

2014-10-28

Castanea mollissima Blume (Chinese chestnut), as a food product is known for its various nutrients and functional values to the human health. The present study was carried out to analyze the anti-diabetic complications and anti-cancer activities of the bioactive compounds present in C. mollissima. The kernels (CK), shells (CS) and involucres (CI) parts of C. Blume were extracted with 90% alcohol. The water suspension of these dried alcohol extracts were extracted using EtOAc and n-BuOH successively. The n-BuOH fraction of CI (CI-B) was isolated by silica gel column, Sephadex LH 20 column and preparative HPLC. The isolated compounds were identified by 1H-NMR, 13C-NMR, HMBC, HMQC and ESI-Q-TOF MS, All the fractions and compounds isolated were evaluated on human recombinant aldose reductase (HR-AR) assay, advanced glycation end products (AGEs) formation assay and human COLO 320 DM colon cancer cells inhibitory assay. CI-B was found to show a significant inhibitory effect in above biological screenings. Six flavonoids and three polyphenolic acids were obtained from CI-B. They were identified as kaempferol (1), kaempferol-3-O-[6''-O-(E)-p-coumaroyl]-β-D-glucopyranoside (2), kaempferol-3-O-[6''-O-(E)-p-coumaroyl]-β-D-galactopyranoside (3), kaempferol-3-O-[2''-O-(E)-p-coumaroyl]-β-D-glucopyranoside (4), kaempferol-3-O-[2", 6"-di-O-(E)-p-coumaroyl]-β-D-glucopyranoside (5) and kaempferol-3-O-[2", 6"-di-O-(E)-p-coumaroyl]-β-D-galactopyranoside (6), casuariin (7), casuarinin (8) and castalagin (9). Compounds 2-9 were found to show higher activity than quercetin (positive control) in the AR assay. Compounds 3-6, 8, and 9 showed stronger inhibitory effects than amino guanidine (positive control) on AGEs production. Compounds 4-6, 7, and 8 showed much higher cytotoxic activity than 5-fluorouracil (positive control) against the human COLO 320 DM colon cancer cells. Our results suggest that flavonoids and polyphenolic acids possesses anti-diabetes complications and anti

'Searching for the people in charge': appraising the 1983 Griffiths NHS management inquiry.

Science.gov (United States)

Gorsky, Martin

2013-01-01

This is the first of two related articles in the present volume which examine the recent history of health services management using the case of the British National Health Service (NHS). In the historiography of the NHS the 1980s is widely seen as a watershed, when public policy first sought to introduce market disciplines into its operation. Administrative and managerial reforms were central to this process, and their origins and impact have been the subject of continuing debate. This article examines and evaluates one of the key events in this history, the Griffiths NHS Inquiry of 1983, which put in place the principles of 'general management' in the NHS. Drawing on both documentary records and oral evidence it offers fresh perspectives on the reasons why the Conservative government embarked on this reform, on the workings of the inquiry team under the leadership of the businessman Roy Griffiths, and on the uneven course of the implementation of his recommendations. While its initial impact arguably did not meet the expectations of its supporters, it is suggested that several of Griffiths' key concerns have grown, not diminished, in importance as aspects of subsequent health politics. These include: the need for clinician involvement in NHS management and financing; the conundrum of how to depoliticise the central direction of the service while retaining political accountability; the desirability of measuring and improving performance; and the question of how best to incorporate the wishes of patients and public in the decision-making arena.

Thermodynamically self-consistent theory for the Blume-Capel model.

Science.gov (United States)

Grollau, S; Kierlik, E; Rosinberg, M L; Tarjus, G

2001-04-01

We use a self-consistent Ornstein-Zernike approximation to study the Blume-Capel ferromagnet on three-dimensional lattices. The correlation functions and the thermodynamics are obtained from the solution of two coupled partial differential equations. The theory provides a comprehensive and accurate description of the phase diagram in all regions, including the wing boundaries in a nonzero magnetic field. In particular, the coordinates of the tricritical point are in very good agreement with the best estimates from simulation or series expansion. Numerical and analytical analysis strongly suggest that the theory predicts a universal Ising-like critical behavior along the lambda line and the wing critical lines, and a tricritical behavior governed by mean-field exponents.

The random field Blume-Capel model revisited

Science.gov (United States)

Santos, P. V.; da Costa, F. A.; de Araújo, J. M.

2018-04-01

We have revisited the mean-field treatment for the Blume-Capel model under the presence of a discrete random magnetic field as introduced by Kaufman and Kanner (1990). The magnetic field (H) versus temperature (T) phase diagrams for given values of the crystal field D were recovered in accordance to Kaufman and Kanner original work. However, our main goal in the present work was to investigate the distinct structures of the crystal field versus temperature phase diagrams as the random magnetic field is varied because similar models have presented reentrant phenomenon due to randomness. Following previous works we have classified the distinct phase diagrams according to five different topologies. The topological structure of the phase diagrams is maintained for both H - T and D - T cases. Although the phase diagrams exhibit a richness of multicritical phenomena we did not found any reentrant effect as have been seen in similar models.

Constraints on Exotic Spin-Dependent Interactions Between Matter and Antimatter from Antiprotonic Helium Spectroscopy

Science.gov (United States)

Ficek, Filip; Fadeev, Pavel; Flambaum, Victor V.; Jackson Kimball, Derek F.; Kozlov, Mikhail G.; Stadnik, Yevgeny V.; Budker, Dmitry

2018-05-01

Heretofore undiscovered spin-0 or spin-1 bosons can mediate exotic spin-dependent interactions between standard model particles. Here, we carry out the first search for semileptonic spin-dependent interactions between matter and antimatter. We compare theoretical calculations and spectroscopic measurements of the hyperfine structure of antiprotonic helium to constrain exotic spin- and velocity-dependent interactions between electrons and antiprotons.

Risk-constrained self-scheduling of a fuel and emission constrained power producer using rolling window procedure

International Nuclear Information System (INIS)

Kazempour, S. Jalal; Moghaddam, Mohsen Parsa

2011-01-01

This work addresses a relevant methodology for self-scheduling of a price-taker fuel and emission constrained power producer in day-ahead correlated energy, spinning reserve and fuel markets to achieve a trade-off between the expected profit and the risk versus different risk levels based on Markowitz's seminal work in the area of portfolio selection. Here, a set of uncertainties including price forecasting errors and available fuel uncertainty are considered. The latter uncertainty arises because of uncertainties in being called for reserve deployment in the spinning reserve market and availability of power plant. To tackle the price forecasting errors, variances of energy, spinning reserve and fuel prices along with their covariances which are due to markets correlation are taken into account using relevant historical data. In order to tackle available fuel uncertainty, a framework for self-scheduling referred to as rolling window is proposed. This risk-constrained self-scheduling framework is therefore formulated and solved as a mixed-integer non-linear programming problem. Furthermore, numerical results for a case study are discussed. (author)

Thomas L. Griffiths: Award for Distinguished Scientific Early Career Contributions to Psychology

Science.gov (United States)

American Psychologist, 2012

2012-01-01

Presents a short biography of one of the winners of the American Psychological Association's Award for Distinguished Scientific Early Career Contributions to Psychology (2012). Thomas L. Griffiths won the award for bringing mathematical precision to the deepest questions in human learning, reasoning, and concept formation. In his pioneering work,…

Transmission through a potential barrier in Luttinger liquids with a topological spin gap

Science.gov (United States)

Kainaris, Nikolaos; Carr, Sam T.; Mirlin, Alexander D.

2018-03-01

We study theoretically the transport of the one-dimensional single-channel interacting electron gas through a strong potential barrier in the parameter regime where the spin sector of the low-energy theory is gapped by interaction (Luther-Emery liquid). There are two distinct phases of this nature, of which one is of particular interest as it exhibits nontrivial interaction-induced topological properties. Focusing on this phase and using bosonization and an expansion in the tunneling strength we calculate the conductance through the barrier as a function of the temperature as well as the local density of states (LDOS) at the barrier. Our main result concerns the mechanism of bound-state-mediated tunneling. The characteristic feature of the topological phase is the emergence of protected zero-energy bound states with fractional spin located at the impurity position. By flipping this fractional spin, single electrons can tunnel across the impurity even though the bulk spectrum for spin excitations is gapped. This results in a finite LDOS below the bulk gap and in a nonmonotonic behavior of the conductance. The system represents an important physical example of an interacting symmetry-protected topological phase, which combines features of a topological spin insulator and a topological charge metal, in which the topology can be probed by measuring transport properties.

Data analysis methods in physical oceanography. By Emery, W.J. and Thomson, R.E.

Digital Repository Service at National Institute of Oceanography (India)

Nayak, M.R.

. 729-730 September 1999 Book Reviews DATA ANALYSIS METHODS IN PHYSICAL O~EAN~GRAFWY. By Wil- liam J. Emery and Richard E. Thomson. PERGAMON Else&r Sci- ence. 1998. 400 p. U.S. $112 / NLG 177.00. The book Data Analysis Methods in Physical... Oceanography pro- vides a comprehensive and practical compilation of the essential information and analysis techniques required for the advanced processing and interpretation of digital spat&temporal data in physical oceanography, as well as in other...

Analytic evidence of the equivalence of the alternating Heisenberg spin chain to the mixed spin (1, 1/2) Heisenberg chain

International Nuclear Information System (INIS)

Jiang Jianjun; Liu Yongjun; Tang Fei; Yang Cuihong

2011-01-01

We investigated the properties of the spin-1/2 ferromagnetic-antiferromagnetic-antiferromagnetic alternating Heisenberg chain using the spin-wave theory. The spin-wave excitation spectra, the sublattice magnetizations and the local bond energies of the model are calculated to be compared with the corresponding properties of the mixed spin (1, 1/2) chain for a range of α. The results demonstrate that all the properties show similar behaviours in the small α limit, so the properties of the mixed spin (1, 1/2) chain can be described using the spin-1/2 ferromagnetic-antiferromagnetic-antiferromagnetic alternating Heisenberg chain. -- Research Highlights: →The spin-wave excitation spectra, the sublattice magnetizations and the local bond energies of the spin-1/2 ferromagnetic-antiferromagnetic-antiferromagnetic alternating Heisenberg chain are calculated. →In the small α limit, the properties of the mixed spin (1,1/2) chain can be described using the spin-1/2 ferromagnetic-antiferromagnetic-antiferromagnetic alternating Heisenberg chain. →The spin-1/2 ferromagnetic-antiferromagnetic-antiferromagnetic alternating Heisenberg chain may be of interest for some real quasi-one-dimensional molecular magnetic materials.

E-Waste and the Sustainable Organisation: Griffith University's Approach to E-Waste

Science.gov (United States)

Davis, Georgina; Wolski, Malcolm

2009-01-01

Purpose: This paper seeks to provide details of Griffith University's (GU) approach for sustainably dealing with electronic waste (e-waste) and the benefits of using the e-waste programme as a valuable educational case study for ESD. Design/methodology/approach: The e-waste programme is explained with reference to key resources and literature, so…

Spin vectors in the Koronis family: III. (832) Karin

Science.gov (United States)

Slivan, Stephen M.; Molnar, Lawrence A.

2012-08-01

Studies of asteroid families constrain models of asteroid collisions and evolution processes, and the Karin cluster within the Koronis family is among the youngest families known (Nesvorný, D., Bottke, Jr., W.F., Dones, L., Levison, H.F. [2002]. Nature 417, 720-722). (832) Karin itself is by far the largest member of the Karin cluster, thus knowledge of Karin's spin vector is important to constrain family formation and evolution models that include spin, and to test whether its spin properties are consistent with the Karin cluster being a very young family. We observed rotation lightcurves of Karin during its four consecutive apparitions in 2006-2009, and combined the new observations with previously published lightcurves to determine its spin vector orientation and preliminary model shape. Karin is a prograde rotator with a period of (18.352 ± 0.003) h, spin obliquity near (42 ± 5)°, and pole ecliptic longitude near either (52 ± 5)° or (230 ± 5)°. The spin vector and shape results for Karin will constrain models of family formation that include spin properties; in the meantime we briefly discuss Karin's own spin in the context of those of other members of the Karin cluster and the parent body's siblings in the Koronis family.

Facebook addiction: a reply to Griffiths (2012).

Science.gov (United States)

Andreassen, Cecilie Schou; Pallesen, Ståle

2013-12-01

Our recent paper about a new Facebook addiction scale has stimulated an interesting and very welcome debate among researchers concerning the assessment of excessive use of social networking sites. The critique put forward by Griffiths (2012) is mainly built on the conception of "Facebook" as too narrow of a concept, and that assessment of addiction to social network sites in general would be more appropriate. We argue that the concept of "social network site" is not more specific than "Facebook," so "Facebook addiction" rather than "social network addiction" is defensible. We acknowledge that more research in this area is needed and point specifically to new and important directions for future research that can shed light on the mechanism of addiction to social network sites.

The World is Spinning: Constraining the Origin of Supermassive Gas Giant Planets at Wide Separations Using Planetary Spin

Science.gov (United States)

Bryan, Marta; Knutson, Heather; Batygin, Konstantin; Benneke, Björn; Bowler, Brendan

2017-01-01

Planetary spin can inform our understanding of planet accretion histories, which determine final masses and atmospheric compositions, as well as the formation of moons and rings. At present, the physics behind how gas giant planets spin up is still very poorly understood. We know that when giant planets form, they accrete material and angular momentum via a circumplanetary disk, causing the planet to spin up. In order to prevent planet spins from reaching break-up velocity, some mechanism must regulate these spins. However, there is currently no well-formulated picture for how planet spins evolve. This is in part due to the fact that there are very few measurements of giant planet spin rates currently available. Outside the solar system, to date there has only been one published spin measurement of a directly imaged planet, beta Pic b. We use Keck/NIRSPEC to measure spin rates for a sample of bound and free-floating directly imaged planetary mass objects, providing a first look at the distribution of spin rates for these objects.

Griffiths-like phase in high TC perovskite La2FeReO6 prepared in a controlled reducing atmosphere

Science.gov (United States)

Kaipamagalath, Aswathi; Palakkal, Jasnamol P.; Varma, Manoj R.

2018-05-01

The perovskite La2FeReO6 is prepared by solid-state reaction method. Calcination was done in a controlled reducing atmosphere. The structure of the compound is found to be orthorhombic with Pbnm space group. From the DC magnetic studies, the transition temperature (TC) of La2FeReO6 is found to be at 729 K. A Griffiths-like phase is present in the material with ferromagnetic short-range correlations above TC up to the Griffiths temperature TG = 863 K.

Taksonomic study on Micromelum Blume (Rutaceae in Indonesia

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TAHAN UJI

2005-04-01

Full Text Available Taxonomic study on Micromelum Blume was conducted at Herbarium Bogoriense (BO and Kew Herbarium (K and using 84 collections number of herbarium specimen. This research used descriptive method based on morphological characters. Terminology by Stearn (1983 was used, whereas the revision method as described by Rifai (1976 and Vogel (1987 were used. Based on this study were produced two species only of Micromelum respectively which occurred in Indonesia. They were Micromelum diversifolium Miq. and M. minutum (Forst. f. Wight. & Arn. M. diversifolium had two varieties, i.e. M. diversifolium Miq. var. diversifolium and M. diversifolium Miq. var. cuneata Miq. Whereas M. minutum had three varieties, i.e. M. minutum (Forst. f. Wight. & Arn. var. minutum, M. minutum (Forst. f. Wight & Arn. var. tomentosum Tan. and M. minutum (Forst. f. Wight & Arn. var. villosum Tan. New record specimen collections of M. diversifolium from Biak Island (Papua was reported also.

A new spin on causality constraints

Energy Technology Data Exchange (ETDEWEB)

Hartman, Thomas; Jain, Sachin; Kundu, Sandipan [Department of Physics, Cornell University, Ithaca, New York (United States)

2016-10-26

Causality in a shockwave state is related to the analytic properties of a four-point correlation function. Extending recent results for scalar probes, we show that this constrains the couplings of the stress tensor to light spinning operators in conformal field theory, and interpret these constraints in terms of the interaction with null energy. For spin-1 and spin-2 conserved currents in four dimensions, the resulting inequalities are a subset of the Hofman-Maldacena conditions for positive energy deposition. It is well known that energy conditions in holographic theories are related to causality on the gravity side; our results make a connection on the CFT side, and extend it to non-holographic theories.

Constraining ΔG at low-x with Double Longitudinal Spin Asymmetries for Forward Hadrons in PHENIX

Science.gov (United States)

McKinney, Cameron; Phenix Collaboration

2013-10-01

Recent global analyses that include polarized p+p data from RHIC through 2009 suggest for the first time a positive contribution of the gluon polarization, ΔG , to the overall proton spin. The data sets included in the analysis constrain Δg (x) in the range 0 . 05 double helicity asymmetry in hadron production at large pseudorapidity, with a dominant contribution from collisions between a high-momentum quark and a low-momentum gluon. At PHENIX, we measure cluster ALL at large pseudorapidity (3 . 1 Piston Calorimeter (MPC). The majority of the clusters (> 80 %) come from π0 decay where the photon showers in the calorimeter overlap. Simulations using the event generator PYTHIA have shown that measuring forward π0's can access Δg (x) for x 10-2 for inclusive π0's or down to x 10-3 for the dihadron channel. Here, we present the status of ALL measurements in the MPC at √{ s } = 500 GeV from the 2011 through 2013 runs. This data will help to provide stronger constraints on the form of Δg (x) in ongoing global analyses.

Ceriops zippeliana Blume (Rhizophoraceae, a New Record of a Mangrove Species in Singapore

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Chiou-Rong Sheue

2010-03-01

Full Text Available Ceriops zippeliana Blume is here reported as a new record for the mangrove forests in Singapore. The botanical description of this new record with color plates and a key to the two Ceriops species in Singapore are provided. It is noteworthy that C. tagal (Perr. C. B. Rob. is rarer than C. zippeliana in Singapore. Thus, special attention for conservation should be focused on C. tagal and a further survey of this genus would provide valuable information to better manage Singapore’s mangrove plant biodiversity.

Injection Induced Seismicity in Carbon and Emery Counties, Utah

Science.gov (United States)

Brown, M. R. M.; Liu, M.

2014-12-01

Utah is one of the top producers of oil and natural gas in the country. Over the past 18 years, more than 4.2 billion gallons of wastewater from the petroleum industry has been injected into the Navajo Sandstone, Kayenta Formation, and Wingate Sandstone in two areas in Carbon and Emery County, Utah. We found that the seismicity rate increased significantly 3 to 5 years following the commencement of wastewater injection. The increased seismicity consists almost entirely of earthquakes with magnitudes of less than 3 and is localized in areas seismically active prior to the injection. We suggest that the marked increase in the seismicity rate was induced by pore pressure increase along pre-existing faults in these areas. We have used simple groundwater models to estimate the change in pore pressure, calculate the pore pressure diffusion rate, and evaluate the observed time gap between the start of injection and the onset of the increased seismicity in the areas surrounding the injection wells.

Heavy spin-2 Dark Matter

Energy Technology Data Exchange (ETDEWEB)

Babichev, Eugeny [Laboratoire de Physique Théorique, CNRS, Univ. Paris-Sud, Université Paris-Saclay,91405 Orsay (France); UPMC-CNRS, UMR7095, Institut d’Astrophysique de Paris, GReCO,98bis boulevard Arago, F-75014 Paris (France); Marzola, Luca; Raidal, Martti [National Institute of Chemical Physics and Biophysics,Rävala 10, 10143 Tallinn (Estonia); Laboratory of Theoretical Physics, Institute of Physics, University of Tartu,Ravila 14c, 50411 Tartu (Estonia); Schmidt-May, Angnis [Institut für Theoretische Physik, Eidgenössische Technische Hochschule Zürich,Wolfgang-Pauli-Strasse 27, 8093 Zürich (Switzerland); Urban, Federico; Veermäe, Hardi [National Institute of Chemical Physics and Biophysics,Rävala 10, 10143 Tallinn (Estonia); Strauss, Mikael von [UPMC-CNRS, UMR7095, Institut d’Astrophysique de Paris, GReCO,98bis boulevard Arago, F-75014 Paris (France)

2016-09-12

We provide further details on a recent proposal addressing the nature of the dark sectors in cosmology and demonstrate that all current observations related to Dark Matter can be explained by the presence of a heavy spin-2 particle. Massive spin-2 fields and their gravitational interactions are uniquely described by ghost-free bimetric theory, which is a minimal and natural extension of General Relativity. In this setup, the largeness of the physical Planck mass is naturally related to extremely weak couplings of the heavy spin-2 field to baryonic matter and therefore explains the absence of signals in experiments dedicated to Dark Matter searches. It also ensures the phenomenological viability of our model as we confirm by comparing it with cosmological and local tests of gravity. At the same time, the spin-2 field possesses standard gravitational interactions and it decays universally into all Standard Model fields but not into massless gravitons. Matching the measured DM abundance together with the requirement of stability constrains the spin-2 mass to be in the 1 to 100 TeV range.

ANATOMY OF GYNURA AURANTIACA (BLUME SCH.BIP. EX DC. (ASTERACEAE

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Rodica BERCU

2014-06-01

Full Text Available The paper presents a detailed histoanatomical description, of the vegetative organs (root, stem and leaf and photographs as well of Gynura aurantiaca (Blume Sch.Bip. ex DC. It was observed that the root have typical primary dictos structure. The stem has a differentiated in two regions cortex and the stele comprise one ring of open collateral vascular bundles with secondary xylem due to the cambium activity. The petiole anatomy is quite similar in its basic structure with the stem. The blade presents a heterogenous and hypostomatic mesophyll and a number of vascular bundles in the midrib zone. Remarkable is the presence of the filamentous, uniseriate non-glandular hairs in the stem, petiole and leaf blade. The mechanical tissue is present in the stem, petiole and blade as well.

Griffith Saponite as an Analog for Clay Minerals at Yellowknife Bay in Gale Crater, Mars: A Marker for Low-temperature Hydrothermal Processes

Science.gov (United States)

Morris, R.V.; Treiman, A. H.; Agresti, D. G.; Graff, T. G.; Achilles, C. N.; Rampe, E. B.; Bristow, T. F.; Ming, D. W.; Blake, D. F.; Vaniman, D. T.;

Professional activity of Emery-Dreifuss muscular dystrophy patients in Poland

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Agnieszka Madej-Pilarczyk

2014-04-01

Full Text Available Objectives: Emery-Dreifuss muscular dystrophy (EDMD is a very rare genetic disorder affecting skeletal and heart muscles. The aim of this study was to identify factors which might influence the ability to work in EDMD patients in Poland. Material and Methods: The study included 24 patients suffering from either of the two EDMD forms: 17 with emerinopathy (EDMD1; EDMD caused by mutations in the emerin gene and 7 with laminopathy (EDMD2; EDMD caused by the lamin A/C gene mutations. After clinical evaluation of EDMD course, study participants were questioned about their education, current and former employment, and disability certificates and pensions. Results: 54% of the study participants were employed, and 90% of them had job position corresponding to their education. Undertaking work did not correlate with the level of physical performance or disease complication, but it revealed statistically significant correlation with a higher level of education (p = 0.015. Only 23% of professionally active patients were employed in a sheltered workplace. Disability certificate was granted to all EDMD2 and to 90% of EDMD1 patients. All EDMD2 and 50% of EDMD1 patients received a disability pension, which reflects more severe course of EDMD2. Conclusions: Higher level of education increased the chance of employment, even if significant disability was present. Therefore, I hypothesize that advice on education and jobcounseling should be applied as early as possible after the diagnosis of EDMD.

Double Spin Asymmetries, ALL, for Di-hadrons in PHENIX

Science.gov (United States)

McKinney, Cameron

2010-11-01

The Relativistic Heavy Ion Collider (RHIC), through its polarized proton-proton collisions, provides leading order access to δG, the gluon contribution to the proton spin. Previous measurements have shown δG(x) dx to be consistent with zero in the Bjorken-x range of 0.05 to 0.2, whereas there is presently no measurement constraining δG (x) for x below or above this range. The Muon Piston Calorimeter provides the opportunity to expand the constrained range by allowing measurements of double spin asymmetries for azimuthally-separated pairs of 0̂'s at forward rapidity, 3.1<=|η|<=3.9, for √s=200 GeV and 500 GeV data taken in 2009. We present PYTHIA simulations studying the kinematics and possible asymmetries from di-hadron production at RHIC.

Observation of a Griffiths-like phase in the paramagnetic regime of ErCo2

International Nuclear Information System (INIS)

Herrero-Albillos, Julia; GarcIa, Luis Miguel; Bartolome, Fernando

2009-01-01

A systematic x-ray magnetic circular dichroism study of the paramagnetic phase of ErCo 2 has recently allowed us to identify the inversion of the net magnetization of the Co net moment with respect to the applied field well above the ferrimagnetic ordering temperature, T c . The study of small-angle neutron scattering measurements has also shown the presence of short range order correlations in the same temperature region. This phenomenon, which we have denoted parimagnetism, may be related to the onset of a Griffiths-like phase in paramagnetic ErCo 2 . We have measured ac susceptibility on ErCo 2 as a function of temperature, applied field and excitation frequency. Several characteristics shared by systems showing a Griffiths phase are present in ErCo 2 , namely the formation of ferromagnetic clusters in the disordered phase, the loss of analyticity of the magnetic susceptibility and its extreme sensitivity to an applied magnetic field. The paramagnetic susceptibility allows us to establish that the magnetic clusters are only formed by Co moments as well as the intrinsic nature of those Co moments.

Comments on spin operators and spin-polarization states of 2+1 fermions

Energy Technology Data Exchange (ETDEWEB)

Gavrilov, S.P.; Tomazelli, J.L. [Departamento Fisica e Quimica, UNESP, Campus de Guaratingueta (Brazil); Gitman, D.M. [Universidade de Sao Paulo, Instituto de Fisica, Caixa Postal 66318-CEP, Sao Paulo, S.P. (Brazil)

2005-02-01

In this brief article we discuss spin-polarization operators and spin-polarization states of 2+1 massive Dirac fermions and find a convenient representation by the help of 4-spinors for their description. We stress that in particular the use of such a representation allows us to introduce the conserved covariant spin operator in the 2+1 field theory. Another advantage of this representation is related to the pseudoclassical limit of the theory. Indeed, quantization of the pseudoclassical model of a spinning particle in 2+1 dimensions leads to the 4-spinor representation as the adequate realization of the operator algebra, where the corresponding operator of a first-class constraint, which cannot be gauged out by imposing the gauge condition, is just the covariant operator previously introduced in the quantum theory. (orig.)

Spin-isotropic continuum of spin excitations in antiferromagnetically ordered Fe1.07Te

Science.gov (United States)

Song, Yu; Lu, Xingye; Regnault, L.-P.; Su, Yixi; Lai, Hsin-Hua; Hu, Wen-Jun; Si, Qimiao; Dai, Pengcheng

2018-02-01

Unconventional superconductivity typically emerges in the presence of quasidegenerate ground states, and the associated intense fluctuations are likely responsible for generating the superconducting state. Here we use polarized neutron scattering to study the spin space anisotropy of spin excitations in Fe1.07Te exhibiting bicollinear antiferromagnetic (AF) order, the parent compound of FeTe1 -xSex superconductors. We confirm that the low-energy spin excitations are transverse spin waves, consistent with a local-moment origin of the bicollinear AF order. While the ordered moments lie in the a b plane in Fe1.07Te , it takes less energy for them to fluctuate out of plane, similar to BaFe2As2 and NaFeAs. At energies above E ≳20 meV, we find magnetic scattering to be dominated by an isotropic continuum that persists up to at least 50 meV. Although the isotropic spin excitations cannot be ascribed to spin waves from a long-range-ordered local-moment antiferromagnet, the continuum can result from the bicollinear magnetic order ground state of Fe1.07Te being quasidegenerate with plaquette magnetic order.

Combining EPR spectroscopy and X-ray crystallography to elucidate the structure and dynamics of conformationally constrained spin labels in T4 lysozyme single crystals.

Science.gov (United States)

Consentius, Philipp; Gohlke, Ulrich; Loll, Bernhard; Alings, Claudia; Heinemann, Udo; Wahl, Markus C; Risse, Thomas

2017-08-09

Electron paramagnetic resonance (EPR) spectroscopy in combination with site-directed spin labeling is used to investigate the structure and dynamics of conformationally constrained spin labels in T4 lysozyme single crystals. Within a single crystal, the oriented ensemble of spin bearing moieties results in a strong angle dependence of the EPR spectra. A quantitative description of the EPR spectra requires the determination of the unit cell orientation with respect to the sample tube and the orientation of the spin bearing moieties within the crystal lattice. Angle dependent EPR spectra were analyzed by line shape simulations using the stochastic Liouville equation approach developed by Freed and co-workers and an effective Hamiltonian approach. The gain in spectral information obtained from the EPR spectra of single crystalline samples taken at different frequencies, namely the X-band and Q-band, allows us to discriminate between motional models describing the spectra of isotropic solutions similarly well. In addition, it is shown that the angle dependent single crystal spectra allow us to identify two spin label rotamers with very similar side chain dynamics. These results demonstrate the utility of single crystal EPR spectroscopy in combination with spectral line shape simulation techniques to extract valuable dynamic information not readily available from the analysis of isotropic systems. In addition, it will be shown that the loss of electron density in high resolution diffraction experiments at room temperature does not allow us to conclude that there is significant structural disorder in the system.

Spin Dynamics in Highly Spin Polarized Co1-xFexS2

Science.gov (United States)

Hoch, Michael J. R.; Kuhns, Philip L.; Moulton, William G.; Reyes, Arneil P.; Lu, Jun; Wang, Lan; Leighton, Chris

2006-09-01

Highly spin polarized or half-metallic systems are of considerable current interest because of their potential for spin injection in spintronics applications. The ferromagnet (FM) CoS2 is close to being a half-metal. Recent theoretical and experimental work has shown that the alloys Co1-xFexS2 (0.07 < x < 0.9) are highly spin polarized at low temperatures. The Fe concentration may be used to tune the spin polarization. Using 59Co FM- NMR we have investigated the spin dynamics in this family of alloys and have obtained information on the evolution of the d-band density of states at the Fermi level with x in the range 0 to 0.3. The results are compared with available theoretical predictions.

Magnetism of one-dimensional strongly repulsive spin-1 bosons with antiferromagnetic spin-exchange interaction

International Nuclear Information System (INIS)

Lee, J. Y.; Guan, X. W.; Batchelor, M. T.; Lee, C.

2009-01-01

We investigate magnetism and quantum phase transitions in a one-dimensional system of integrable spin-1 bosons with strongly repulsive density-density interaction and antiferromagnetic spin-exchange interaction via the thermodynamic Bethe ansatz method. At zero temperature, the system exhibits three quantum phases: (i) a singlet phase of boson pairs when the external magnetic field H is less than the lower critical field H c1 ; (ii) a ferromagnetic phase of atoms in the hyperfine state |F=1, m F =1> when the external magnetic field exceeds the upper critical field H c2 ; and (iii) a mixed phase of singlet pairs and unpaired atoms in the intermediate region H c1 c2 . At finite temperatures, the spin fluctuations affect the thermodynamics of the model through coupling the spin bound states to the dressed energy for the unpaired m F =1 bosons. However, such spin dynamics is suppressed by a sufficiently strong external field at low temperatures. Thus the singlet pairs and unpaired bosons may form a two-component Luttinger liquid in the strong coupling regime.

Minimal models from W-constrained hierarchies via the Kontsevich-Miwa transform

CERN Document Server

Gato-Rivera, Beatriz

1992-01-01

A direct relation between the conformal formalism for 2d-quantum gravity and the W-constrained KP hierarchy is found, without the need to invoke intermediate matrix model technology. The Kontsevich-Miwa transform of the KP hierarchy is used to establish an identification between W constraints on the KP tau function and decoupling equations corresponding to Virasoro null vectors. The Kontsevich-Miwa transform maps the $W^{(l)}$-constrained KP hierarchy to the $(p^\\prime,p)$ minimal model, with the tau function being given by the correlator of a product of (dressed) $(l,1)$ (or $(1,l)$) operators, provided the Miwa parameter $n_i$ and the free parameter (an abstract $bc$ spin) present in the constraints are expressed through the ratio $p^\\prime/p$ and the level $l$.

Spin-1 Dirac-Weyl fermions protected by bipartite symmetry

Energy Technology Data Exchange (ETDEWEB)

Lin, Zeren [College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); School of Physics, Peking University, Beijing 100871 (China); Liu, Zhirong, E-mail: LiuZhiRong@pku.edu.cn [College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), Peking University, Beijing 100871 (China)

2015-12-07

We propose that bipartite symmetry allows spin-1 Dirac-Weyl points, a generalization of the spin-1/2 Dirac points in graphene, to appear as topologically protected at the Fermi level. In this spirit, we provide methodology to construct spin-1 Dirac-Weyl points of this kind in a given 2D space group and get the classification of the known spin-1 systems in the literature. We also apply the workflow to predict two new systems, P3m1-9 and P31m-15, to possess spin-1 at K/K′ in the Brillouin zone of hexagonal lattice. Their stability under various strains is investigated and compared with that of T{sub 3}, an extensively studied model of ultracold atoms trapped in optical lattice with spin-1 also at K/K′.

A possible interaction between spin-1/2 and spin-3/2 fields

International Nuclear Information System (INIS)

Fleury, N.; Lopes, J.L.

1984-01-01

A straighforward extension of the standard Weinberg-Salam model to Rarita-Schwinger formalism, is a heuristic way to obtain electroweak currents for spin-3/2 leptons. A new interaction between spin-1/2 and spin-3/2 particles that maintains the SU(2) x U(1) gauge invariance is postulated and a possible form for the interaction involving these two types of particles and the gauge fields is obtained. This takes place through a coupling which involves derivatives of the electromagnetic field and the corresponding coupling constant is inversely proportional to the mass of spin-3/2 particles. Several reactions are possible with this new interaction such as the radiative decay of a charged Rarita-Schwinger particle. Other reactions are corrections to well-known processes: for instance, in the usual Compton effect, the fermionic virtual line can be replaced by the corresponding spin-3/2 one. But, due to the large mass of the spin-3/2 lepton, these corrections are significantly non negligible only at ultra relativistic energies. On the other hand, in the low energy limit this correction gives fortunately no contribution to the Thomson cross section because the coupling 3/2 - 1/2 - γ is proportional to the photon's momentum. If it is considered all the possible couplings of these fields, one can combine them in diagrams of lowest orders whose theoretical predictions have to be submitted to experimental pressure. (Author) [pt

A possible interaction between spin-1/2 and spin-3/2 fields

International Nuclear Information System (INIS)

Fleury, N.; Leite Lopes, J.

1984-01-01

A straightforward extension of the standard Weinberg-Salam model to Rarita-Schwinger formalism, is a heuristic way to obtain electroweak currents for spin-3/2 leptons. We postulate a new interaction between spin-1/2 and spin-3/2 particles that maintains the SU(2) x U(1) gauge invariance, and we obtain a possible form for the interaction involving these two types of particles and the gauge fields. This takes place through a coupling which involves derivatives of the electromagnetic field and the corresponding coupling constant is inversely proportional to the mass of spin-3/2 particles. Several reactions are possible with this new interaction such as the radiative decay of a charged Rarita-Schwinger particle. Other reactions are corrections to well-known processes: for instance, in the usual Compton effect, the fermionic virtual line can be replaced by the corresponding spin-3/2 one. But, due to the large mass of the spin-3/2 lepton, these corrections are significantly non negligible only at ultra relativistic energies. On the other hand, in the low energy limit this correction gives fortunately no contribution to the Thomson cross section because the coupling 3/2-1/2-γ is proportional to the photon's momentum. If one considers all the possible couplings of these fields, one can combine them in diagrams of lowest orders whose theoretical predictions have to be submitted to experimental pressure

Exact solution of the mixed spin-1/2 and spin-S Ising-Heisenberg diamond chain

Directory of Open Access Journals (Sweden)

L. Čanová

2009-01-01

Full Text Available The geometric frustration in a class of the mixed spin-1/2 and spin-S Ising-Heisenberg diamond chains is investigated by combining three exact analytical techniques: Kambe projection method, decoration-iteration transformation and transfer-matrix method. The ground state, the magnetization process and the specific heat as a function of the external magnetic field are particularly examined for different strengths of the geometric frustration. It is shown that the increase of the Heisenberg spin value S raises the number of intermediate magnetization plateaux, which emerge in magnetization curves provided that the ground state is highly degenerate on behalf of a sufficiently strong geometric frustration. On the other hand, all intermediate magnetization plateaux merge into a linear magnetization versus magnetic field dependence in the limit of classical Heisenberg spin S → ∞. The enhanced magnetocaloric effect with cooling rate exceeding the one of paramagnetic salts is also detected when the disordered frustrated phase constitutes the ground state and the external magnetic field is small enough.

Induced seismicity in Carbon and Emery counties, Utah

Science.gov (United States)

Brown, Megan R. M.

Utah is one of the top producers of oil and natural gas in the United States. Over the past 18 years, more than 4.2 billion gallons of wastewater from the petroleum industry have been injected into the Navajo Sandstone, Kayenta Formation, and Wingate Sandstone in two areas in Carbon and Emery County, Utah, where seismicity has increased during the same period. In this study, I investigated whether or not wastewater injection is related to the increased seismicity. Previous studies have attributed all of the seismicity in central Utah to coal mining activity. I found that water injection might be a more important cause. In the coal mining area, seismicity rate increased significantly 1-5 years following the commencement of wastewater injection. The increased seismicity consists almost entirely of earthquakes with magnitudes of less than 3, and is localized in areas seismically active prior to the injection. I have established the spatiotemporal correlations between the coal mining activities, the wastewater injection, and the increased seismicity. I used simple groundwater models to estimate the change in pore pressure and evaluate the observed time gap between the start of injection and the onset of the increased seismicity in the areas surrounding the injection wells. To ascertain that the increased seismicity is not fluctuation of background seismicity, I analyzed the magnitude-frequency relation of these earthquakes and found a clear increase in the b-value following the wastewater injection. I conclude that the marked increase of seismicity rate in central Utah is induced by both mining activity and wastewater injection, which raised pore pressure along pre-existing faults.

Correlation between the nucleation of a Griffiths-like Phase and Colossal Magnetoresistance across the compositional metal-insulator boundary in La1-xCaxMnO3

International Nuclear Information System (INIS)

Jiang Wanjun; Zhou Xuezhi; Williams, Gwyn; Privezentsev, R; Mukovskii, Y

2010-01-01

Detailed measurements of the magnetic and transport properties of single crystals La 1-x Ca x MnO 3 (0.18 ≤ x ≤ 0.27) are summarized; comparisons between which (i) not only confirm that Griffiths Phase-like(GP) features are not a prerequisite for CMR, but also demonstrate that the presence of GP-like characteristics do not guarantee the appearance of CMR; (ii) indicate that whereas continuous magnetic transitions occur for 0.18 ≤ x ≤ 0.25, the universality class of these transitions belongs to that of nearest-neighbour 3D Heisenberg model only for x ≤ 0.20, beyond which complications due to GP-like behaviour occur.

Evaluation of emery dust on the manufacture of abrasives by neutron activation analysis and atomic absorption spectroscopy

International Nuclear Information System (INIS)

Granados Correa, F.

1992-01-01

In this work it is presented an evaluation on the degree of contamination by emery dust in a working area where abrasives are manufactured, in a factory located in the industrial area of Toluca City by neutron activation analysis and atomic absorption spectroscopy. The samples were collected on Whatman filters and attacked with hot concentrated HCl. The elements founded were: Al, Si, V, Mg, Br, Mn, Ni, Zn, Fe, Cr, Ca and Pb. They are a risk for the health of the workers. (Author)

Gamma Irradiation on Growth and Development of Amorphophallus muelleri Blume.

Directory of Open Access Journals (Sweden)

Edi Santosa

2014-09-01

Full Text Available ABSTRACT Iles-iles (Amorphophallus muelleri Blume produces apomictic seeds lead to low genetic variation. In order to induce genetic variation, germinated seeds were exposed to Gamma irradiation (Co-60 at doses of 10 to 100 Gy. Seed irradiation was conducted at Center for the Application of Isotope and Irradiation Technology -National Nuclear Energy Agency (CAIRT, Indonesia. Morphology and yield of M1 generation were observed. Results showed that irradiation at a dose of 10 Gy close to LD50 with survival rate 56%. Gamma irradiation at a dose of 10 Gy delayed seeds germination.  Germination rates gradually increased and reached maximum at 4 weeks after planting (WAP for control plants, and 14 WAP of irradiated plants. At 16 WAP, germination rate of 10 Gy irradiated plants was 56% and 84% for those of control plants. Irradiation induced chimera as indicated by short petiole, variegated and abnornal shape of leaflets. Some irradiated plants entered dormancy at 8-10 weeks later than control ones. Prolong vegetative periode lead the plants to produce heavier corms. This study revealed the possibility to induce variation of A. muelleri by using gamma irradition. Keywords: Amorphophallus muelleri, gamma irradiation (Co-60, morphological variation, mutation breeding

Phase transitions and spin excitations of spin-1 bosons in optical lattice

Science.gov (United States)

Zhu, Min-Jie; Zhao, Bo

2018-03-01

For spin-1 bosonic system trapped in optical lattice, we investigate two main problems, including MI-SF phase transition and magnetic phase separations in MI phase, with extended standard basis operator (SBO) method. For both ferromagnetic (U2 0) systems, we analytically figure out the symmetry properties in Mott-insulator and superfluid phases, which would provide a deeper insight into the MI-SF phase transition process. Then by applying self-consistent approach to the method, we include the effect of quantum and thermal fluctuations and derive the MI-SF transition phase diagram, which is in quantitative agreement with recent Monte-Carlo simulation at zero temperature, and at finite temperature, we find the underestimation of finite-temperature-effect in the mean-field approximation method. If we further consider the spin excitations in the insulating states of spin-1 system in external field, distinct spin phases are expected. Therefore, in the Mott lobes with n = 1 and n = 2 atoms per site, we give analytical and numerical boundaries of the singlet, nematic, partially magnetic and ferromagnetic phases in the magnetic phase diagrams.

Spin 0 and spin 1/2 quantum relativistic particles in a constant gravitational field

International Nuclear Information System (INIS)

Khorrami, M.; Alimohammadi, M.; Shariati, A.

2003-01-01

The Klein-Gordon and Dirac equations in a semi-infinite lab (x>0), in the background metric ds 2 =u 2 (x)(-dt 2 +dx 2 )+dy 2 +dz 2 , are investigated. The resulting equations are studied for the special case u(x)=1+gx. It is shown that in the case of zero transverse-momentum, the square of the energy eigenvalues of the spin-1/2 particles are less than the squares of the corresponding eigenvalues of spin-0 particles with same masses, by an amount of mgℎc. Finally, for non-zero transverse-momentum, the energy eigenvalues corresponding to large quantum numbers are obtained and the results for spin-0 and spin-1/2 particles are compared to each other

Superstring sigma models from spin chains: the SU(1,1 vertical bar 1) case

International Nuclear Information System (INIS)

Bellucci, S.; Casteill, P.-Y.; Morales, J.F.

2005-01-01

We derive the coherent state representation of the integrable spin chain Hamiltonian with non-compact supersymmetry group G=SU(1,1 vertical bar 1). By passing to the continuous limit, we find a spin chain sigma model describing a string moving on the supercoset G/H, H being the stabilizer group. The action is written in a manifestly G-invariant form in terms of the Cartan forms and the string coordinates in the supercoset. The spin chain sigma model is shown to agree with that following from the Green-Schwarz action describing two-charged string spinning on AdS 5 xS 5

Measuring Quasar Spin via X-ray Continuum Fitting

Science.gov (United States)

Jenkins, Matthew; Pooley, David; Rappaport, Saul; Steiner, Jack

2018-01-01

We have identified several quasars whose X-ray spectra appear very soft. When fit with power-law models, the best-fit indices are greater than 3. This is very suggestive of thermal disk emission, indicating that the X-ray spectrum is dominated by the disk component. Galactic black hole binaries in such states have been successfully fit with disk-blackbody models to constrain the inner radius, which also constrains the spin of the black hole. We have fit those models to XMM-Newton spectra of several of our identified soft X-ray quasars to place constraints on the spins of the supermassive black holes.

The molecular spin filter constructed from 1D organic chain

International Nuclear Information System (INIS)

Chen, Wei; Xu, Ning; Wang, Baolin; Bian, Baoan

2014-01-01

We proposed a molecular spin filter, which is constructed from the 1D metallic organic chain (Fe n+1 (C 6 H 4 ) n ). The spin-polarized transport properties of the molecular spin filter are explored by combining density functional theory with nonequilibrium Green's function formalism. Theoretical results reveal that Fe n+1 (C 6 H 4 ) n molecular chain exhibits robust spin filtering effect, and only the spin-down electrons can transmit through the molecular chain. At the given bias voltage window [−1 eV,1 eV], the calculated spin filter efficiency is close to 100% in the case of n≥3. We find that the effect of spin polarization origin from both Fe n+1 and (C 6 H 4 ) n . In addition, negative difference resistance behavior appears in Fe n+1 (C 6 H 4 ) n molecular chain. The results can help us understand the spin transport properties of organic molecular chain. - Highlights: • Theoretical results reveal that Fe n+1 (C 6 H 4 ) n molecular chain exhibits robust spin filtering effect. • The effect of spin polarization origin from both of Fe n+1 and (C 6 H 4 ) n . • Negative difference resistance behavior appears in Fe n+1 (C 6 H 4 ) n molecular chain

Universality from disorder in the random-bond Blume-Capel model

Science.gov (United States)

Fytas, N. G.; Zierenberg, J.; Theodorakis, P. E.; Weigel, M.; Janke, W.; Malakis, A.

2018-04-01

Using high-precision Monte Carlo simulations and finite-size scaling we study the effect of quenched disorder in the exchange couplings on the Blume-Capel model on the square lattice. The first-order transition for large crystal-field coupling is softened to become continuous, with a divergent correlation length. An analysis of the scaling of the correlation length as well as the susceptibility and specific heat reveals that it belongs to the universality class of the Ising model with additional logarithmic corrections which is also observed for the Ising model itself if coupled to weak disorder. While the leading scaling behavior of the disordered system is therefore identical between the second-order and first-order segments of the phase diagram of the pure model, the finite-size scaling in the ex-first-order regime is affected by strong transient effects with a crossover length scale L*≈32 for the chosen parameters.

Review: Kandungan Mannan pada Tanaman Iles-iles (Amorphophallus muelleri Blume.

Directory of Open Access Journals (Sweden)

SUMARWOTO

2007-05-01

Full Text Available Mannan is a kind of polysaccharide that shaped from mannose and glucose with molar ratio 3:2. Sum of total mannan have a variation rate, influenced by the age, kind of plant, beginning treatment before drying and many other reason. This kind of carbohydrate is important for the plant, it self, and for human, it can be used for many industries. This polysaccharide produced most by a tuber like iles-iles (Amorphophallus muelleri Blume. mannan polymer has a special character which have an attitude between cellulose and galactomannan, so have and ability to crystallize and shaping soft patterns. Besides Amorphophallus, mannan can be found in a small number of another plant, like Ivory nut, and some of Orchidaceae and some in subdivision Gymnosperm. The way to isolate can be in physically and chemically. And the benefits are for the development of many industries, like food, medical, paper, laboratory, etc.

Scaling behavior of spin gap of the bond alternating anisotropic spin-1/2 Heisenberg chain

Energy Technology Data Exchange (ETDEWEB)

Paul, Susobhan, E-mail: suso.phy.paul@gmail.com [Department of Physics, Scottish Church College, 1 & 3 Urquhart Square, Kolkata-700006 (India); Ghosh, Asim Kumar, E-mail: asimkumar96@yahoo.com [Department of Physics, Jadavpur University, 188 Raja S C Mallik Road, Kolkata-700032 (India)

2016-05-06

Scaling behavior of spin gap of a bond alternating spin-1/2 anisotropic Heisenberg chain has been studied both in ferromagnetic (FM) and antiferromagnetic (AFM) cases. Spin gap has been estimated by using exact diagonalization technique. All those quantities have been obtained for a region of anisotropic parameter Δ defined by 0≤Δ≤1. Spin gap is found to develop as soon as the non-uniformity in the alternating bond strength is introduced in the AFM regime which furthermore sustains in the FM regime as well. Scaling behavior of the spin gap has been studied by introducing scaling exponent. The variation of scaling exponents with Δ is fitted with a regular function.

Magnetic monopole dynamics in spin ice.

Science.gov (United States)

Jaubert, L D C; Holdsworth, P C W

2011-04-27

One of the most remarkable examples of emergent quasi-particles is that of the 'fractionalization' of magnetic dipoles in the low energy configurations of materials known as 'spin ice' into free and unconfined magnetic monopoles interacting via Coulomb's 1/r law (Castelnovo et al 2008 Nature 451 42-5). Recent experiments have shown that a Coulomb gas of magnetic charges really does exist at low temperature in these materials and this discovery provides a new perspective on otherwise largely inaccessible phenomenology. In this paper, after a review of the different spin ice models, we present detailed results describing the diffusive dynamics of monopole particles starting both from the dipolar spin ice model and directly from a Coulomb gas within the grand canonical ensemble. The diffusive quasi-particle dynamics of real spin ice materials within the 'quantum tunnelling' regime is modelled with Metropolis dynamics, with the particles constrained to move along an underlying network of oriented paths, which are classical analogues of the Dirac strings connecting pairs of Dirac monopoles.

Aftermath of Griffith Park Fire

Science.gov (United States)

2007-01-01

In mid-May 2007, wind-driven flames raced through Griffith Park in Los Angeles, forcing hasty evacuations and threatening numerous famous landmarks and tourist spots, such as the Los Angeles Zoo and the Hollywood Sign. Ultimately, no one was injured in the fire, which may have been started by a cigarette. About 800 acres burned in the urban park, which is itself a Hollywood landmark, having been the location for several movies, including Rebel Without A Cause. This image of the park was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite on June 6, 2007, about a month after the fire. ASTER detects both visible and infrared wavelengths of light, and both kinds have been used to make this image. Vegetation appears in various shades of red, while the burned areas appear charcoal. Roads and dense urban areas appear purplish-gray or white. Water is dark blue. Large burned areas are evident in the northwest and southeast parts of the park, with scattered smaller patches along the southern margin. Some botanical gardens and parts of a bird sanctuary, as well as some park structures like restrooms, were destroyed. The park's unburned, natural vegetation appears brick red, while the irrigated golf courses adjacent to the park are bright red. NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

PENGGUNAAN MIKORIZA DAN PUPUK NPK DALAM PEMBIBITAN NYAWAI (Ficus variegata Blume

Directory of Open Access Journals (Sweden)

NFN Danu

2016-12-01

Full Text Available Kebutuhan bahan baku  untuk industri pengolahan kayu dan serat dari tahun ke tahun semakin meningkat, sedangkan pasokan bahan baku dari hutan alam semakin menurun, akibatnya terjadi kelangkaan bahan baku industri pengolahan kayu dan pulp. Oleh karena itu perlu dilakukan pengembangan hutan tanaman yang memadai. Tanaman nyawai (Ficus variegata Blume  merupakan jenis alternatif prioritas dalam pembangunan hutan tanaman penghasil kayu. Salah satu faktor yang menentukan keberhasilan pengembangan hutan tanaman nyawai adalah penggunaan bibit bermutu, karena bibit yang berkualitas akan menghasilkan tegakan dengan tingkat produktivitas tinggi. Pengadaan bibit nyawai bermutu dapat melalui teknik perbanyakan generatif maupun vegetatif. Tujuan penelitian ini adalah untuk mendapatkan kombinasi pemupukan dan mikoriza yang tepat untuk menghasilkan bibit nyawai yang berkualitas. Buah nyawai dikumpulkan dari Kebun Raya Cibodas (Cianjur. Lokasi Penelitian di persemaian Nagrak. Perkecambahan dilakukan dengan menabur benih pada bak kecambah yang berisi media yang telah disterilkan. Media penyapihan menggunakan tanah sub soil ditambah mikoriza: tanpa mikoriza (C0, Glomus sp. (C1, Acaulospora sp. (C2 dan dosis NPK sebanyak : 0,0 g (P0, 0,5 g/polybag (P1, 1,0 g/poybag (P2. Pengadaan bibit nyawai dapat menggunakan campuran media tanah subsoil + 30 % serbuk sabut kelapa (coco peat +10 % arang sekam padi (v/v, CMA Glomus sp dan Acaulospora sp mampu berkolonisasi dengan akar bibit nyawai. Pemberian pupuk NPK 0,5 – 1,0 gram per polybag dapat meningkatkan serapan hara P.

Dynamics of dimer and z spin component fluctuations in spin-1/2 XY chain

Directory of Open Access Journals (Sweden)

P.Hlushak

2005-01-01

Full Text Available One-dimensional quantum spin-1/2 XY models admit the rigorous analysis not only of their static properties (i.e. the thermodynamic quantities and the equal-time spin correlation functions but also of their dynamic properties (i.e. the different-time spin correlation functions, the dynamic susceptibilities, the dynamic structure factors. This becomes possible after exploiting the Jordan-Wigner transformation which reduces the spin model to a model of spinless noninteracting fermions. A number of dynamic quantities (e.g. related to transverse spin operator or dimer operator fluctuations are entirely determined by two-fermion excitations and can be examined in much detail.

Spin-polarized hydrogen, deuterium, and tritium : I

International Nuclear Information System (INIS)

Haugen, M.; Ostgaard, E.

1989-01-01

The ground-state energy of spin-polarized hydrogen, deuterium and tritium is calculated by means of a modified variational lowest order constrained-variation method, and the calculations are done for five different two-body potentials. Spin-polarized H is not self-bound according to our theoretical results for the ground-state binding energy. For spin-polarized D, however, we obtain theoretical results for the ground-state binding energy per particle from -0.4 K at an equilibrium particle density of 0.25 σ -3 or a molar volume of 121 cm 3 /mol to +0.32 K at an equilibrium particle density of 0.21 σ -3 or a molar volume of 142 cm 3 /mol, where σ = 3.69 A (1A = 10 -10 m). It is, therefore, not clear whether spin-polarized deuterium should be self-bound or not. For spin-polarized T, we obtain theoretical results for the ground-state binding energy per particle from -4.73 K at an equilibrium particle density of 0.41 σ -3 or a molar volume of 74 cm 3 /mol to -1.21 K at an equilibrium particle density of 0.28 σ -3 or a molar volume of 109 cm 3 /mol. (Author) 27 refs., 9 figs., tab

Spin-labeled 1-alkyl-1-nitrosourea synergists of antitumor antibiotics.

Science.gov (United States)

Gadjeva, V; Koldamova, R

2001-01-01

A new method for synthesis of four spin-labeled structural analogues of the antitumor drug 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), using ethyl nitrite for nitrosation of the intermediate spin-labeled ureas has been described. In vitro synergistic effects of 1-ethyl-3-[4-(2,2,6,6-tetramethylpiperidine-1-oxyl)]-1-nitrosourea (3b) on the cytotoxicity of bleomycin and farmorubicin were found in human lymphoid leukemia tumor cells. We measured the tissue distribution of 3b in organ homogenates of C57BL mice by an electron paramagnetic resonance method. The spin-labeled nitrosourea was mainly localized in the lungs. Our results strongly support the development and validation of a new approach for synthesis of less toxic nitrosourea derivatives as potential synergists of antitumor drugs.

Modeling Dzyaloshinskii-Moriya Interaction at Transition Metal Interfaces: Constrained Moment versus Generalized Bloch Theorem

KAUST Repository

Dong, Yao-Jun

2017-10-29

Dzyaloshinskii-Moriya interaction (DMI) at Pt/Co interfaces is investigated theoretically using two different first principles methods. The first one uses the constrained moment method to build a spin spiral in real space, while the second method uses the generalized Bloch theorem approach to construct a spin spiral in reciprocal space. We show that although the two methods produce an overall similar total DMI energy, the dependence of DMI as a function of the spin spiral wavelength is dramatically different. We suggest that long-range magnetic interactions, that determine itinerant magnetism in transition metals, are responsible for this discrepancy. We conclude that the generalized Bloch theorem approach is more adapted to model DMI in transition metal systems, where magnetism is delocalized, while the constrained moment approach is mostly applicable to weak or insulating magnets, where magnetism is localized.

Modeling Dzyaloshinskii-Moriya Interaction at Transition Metal Interfaces: Constrained Moment versus Generalized Bloch Theorem

KAUST Repository

Dong, Yao-Jun; Belabbes, Abderrezak; Manchon, Aurelien

2017-01-01

Dzyaloshinskii-Moriya interaction (DMI) at Pt/Co interfaces is investigated theoretically using two different first principles methods. The first one uses the constrained moment method to build a spin spiral in real space, while the second method uses the generalized Bloch theorem approach to construct a spin spiral in reciprocal space. We show that although the two methods produce an overall similar total DMI energy, the dependence of DMI as a function of the spin spiral wavelength is dramatically different. We suggest that long-range magnetic interactions, that determine itinerant magnetism in transition metals, are responsible for this discrepancy. We conclude that the generalized Bloch theorem approach is more adapted to model DMI in transition metal systems, where magnetism is delocalized, while the constrained moment approach is mostly applicable to weak or insulating magnets, where magnetism is localized.

On the spin-dependent sensitivity of XENON100

Energy Technology Data Exchange (ETDEWEB)

Garny, Mathias [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ibarra, Alejandro; Pato, Miguel; Vogl, Stefan [Technische Univ. Muenchen, Garching (Germany). Physik-Department

2012-11-15

The latest XENON100 data severely constrains dark matter elastic scattering off nuclei, leading to impressive upper limits on the spin-independent cross-section. The main goal of this paper is to stress that the same data set has also an excellent spin-dependent sensitivity, which is of utmost importance in probing dark matter models. We show in particular that the constraints set by XENON100 on the spin-dependent neutron cross-section are by far the best at present, whereas the corresponding spin-dependent proton limits lag behind other direct detection results. The effect of nuclear uncertainties on the structure functions of xenon isotopes is analysed in detail and found to lessen the robustness of the constraints, especially for spin-dependent proton couplings. Notwith-standing, the spin-dependent neutron prospects for XENON1T and DARWIN are very encouraging. We apply our constraints to well-motivated dark matter models and demonstrate that in both mass-degenerate scenarios and the minimal supersymmetric standard model the spin-dependent neutron limits can actually override the spin-independent limits. This opens the possibility of probing additional unexplored regions of the dark matter parameter space with the next generation of ton-scale direct detection experiments.

On the spin-dependent sensitivity of XENON100

International Nuclear Information System (INIS)

Garny, Mathias; Ibarra, Alejandro; Pato, Miguel; Vogl, Stefan

2012-11-01

The latest XENON100 data severely constrains dark matter elastic scattering off nuclei, leading to impressive upper limits on the spin-independent cross-section. The main goal of this paper is to stress that the same data set has also an excellent spin-dependent sensitivity, which is of utmost importance in probing dark matter models. We show in particular that the constraints set by XENON100 on the spin-dependent neutron cross-section are by far the best at present, whereas the corresponding spin-dependent proton limits lag behind other direct detection results. The effect of nuclear uncertainties on the structure functions of xenon isotopes is analysed in detail and found to lessen the robustness of the constraints, especially for spin-dependent proton couplings. Notwith-standing, the spin-dependent neutron prospects for XENON1T and DARWIN are very encouraging. We apply our constraints to well-motivated dark matter models and demonstrate that in both mass-degenerate scenarios and the minimal supersymmetric standard model the spin-dependent neutron limits can actually override the spin-independent limits. This opens the possibility of probing additional unexplored regions of the dark matter parameter space with the next generation of ton-scale direct detection experiments.

Spin-resolved photoemission of surface states of W(110)-(1x1)H

International Nuclear Information System (INIS)

Hochstrasser, M.; Tobin, J.G.; Rotenberg, Eli; Kevan, S.D.

2002-01-01

The surface electronic states of W(110)-(1x1)H have been measured using spin- and angle-resolved photoemission. We directly demonstrate that the surface bands are both split and spin-polarized by the spin-orbit interaction in association with the loss of inversion symmetry near a surface. We observe 100 percent spin polarization of the surface states, with the spins aligned in the plane of the surface and oriented in a circular fashion relative to the S-bar symmetry point. In contrast, no measurable polarization of nearby bulk states is observed

Magnetic and electric order in the spin-1/2 XX model with three-spin interactions

Energy Technology Data Exchange (ETDEWEB)

Thakur, Pradeep; Durganandini, P. [Department of Physics, University of Pune, Ganeshkhind, Pune - 411007 (India)

2016-05-23

We study the spin-1/2 XX model in the presence of three-spin interactions of the XZX+YZY and XZY-YZX types. We solve the problem exactly and show that there is both finite magnetization and electric polarization for low non-zero strengths of the three-spin interactions.

Bimodule structure in the periodic gℓ(1|1) spin chain

International Nuclear Information System (INIS)

Gainutdinov, A.M.; Read, N.; Saleur, H.

2013-01-01

This paper is the second in a series devoted to the study of periodic super-spin chains. In our first paper (Gainutdinov et al., 2013 [3]), we have studied the symmetry algebra of the periodic gℓ(1|1) spin chain. In technical terms, this spin chain is built out of the alternating product of the gℓ(1|1) fundamental representation and its dual. The local energy densities — the nearest neighbour Heisenberg-like couplings — provide a representation of the Jones–Temperley–Lieb (JTL) algebra JTL N . The symmetry algebra is then the centralizer of JTL N , and turns out to be smaller than for the open chain, since it is now only a subalgebra of U q sℓ(2) at q=i — dubbed U q odd sℓ(2) in Gainutdinov et al. (2013) [3]. A crucial step in our associative algebraic approach to bulk logarithmic conformal field theory (LCFT) is then the analysis of the spin chain as a bimodule over U q odd sℓ(2) and JTL N . While our ultimate goal is to use this bimodule to deduce properties of the LCFT in the continuum limit, its derivation is sufficiently involved to be the sole subject of this paper. We describe representation theory of the centralizer and then use it to find a decomposition of the periodic gℓ(1|1) spin chain over JTL N for any even N and ultimately a corresponding bimodule structure. Applications of our results to the analysis of the bulk LCFT will then be discussed in the third part of this series

Quantum Spin Models for Copper Oxide Chains in High-T{sub c} Superconductors

Energy Technology Data Exchange (ETDEWEB)

Haugerud, H.

1996-12-31

This doctoral thesis presents some of the most important features of high temperature superconductors, emphasizing the properties of YBa{sub 2}Cu{sub 3}O{sub 6+x} (YBCO). The family of Hubbard-like models is considered and a simplified version of the Emery model derived. This model is applied to fermions on a cyclic chain and solved analytically in the strong correlation limit. For realistic model parameter values the effects of an external magnetic field is investigated by numerical diagonalization. Applying the Emery model to finite cyclic Cu-O chains it is shown that the behaviour of the chains is typical for a 1D Fermi-liquid. The relatively small difference between the values of the local charge and the local magnetic moment indicates that the degree of correlation in this system is very high. The ground state of the Emery model is shown to be antiferromagnetic for half and quarter filling, resembling the ground state of the Heisenberg model. The role of the ensemble of Cu-O chain fragments of the oxygen deficient planes of YBCO is addressed. By applying the Emery model to short Cu-O chains and calculating the free energy of the chains, the parameters of an Ising like lattice gas model are estimated. Several thermodynamical quantities are calculated by applying Monte Carlo technique to the model. The charge transfer from the chains to the planes is shown to correspond to the measured values of T{sub c}. The phase diagram and the average chain length agree well with experiments. The model is also capable of explaining the behaviour of the REBCO series of superconductors, where RE are various rare earth ions. A framework for simultaneously visualizing and computing numerical quantities from lattice simulations is presented and illustrated. 195 refs., 69 figs., 4 tabs.

Dynamic behaviour of the icosahedral Al–Pd–Mn quasicrystal with a Griffith crack

International Nuclear Information System (INIS)

Xiao-Fang, Wang; Ai-Yu, Zhu; Tian-You, Fan

2009-01-01

The dynamic response of an icosahedral Al–Pd–Mn quasicrystal with a Griffith crack to impact loading is investigated in this paper. The elastohydrodynamic model for the wave propagation and diffusion together with their interaction is adopted. Numerical results of stress, displacement and dynamic stress intensity factors are obtained by using the finite difference method. The effects of wave propagation, diffusion and phonon–phason coupling on the quasicrystal in the dynamic process are discussed in detail, where the phason dynamics is explored particularly. (condensed matter: structure, thermal and mechanical properties)

Microwave Amplitude Modulation Technique to Measure Spin-Lattice (T 1) and Spin-Spin (T 2) Relaxation Times

Science.gov (United States)

Misra, Sushil K.

The measurement of very short spin-lattice, or longitudinal, relaxation (SLR) times (i.e., 10-10 Misra, 1998), and polymer resins doped with rare-earth ions (Pescia et al., 1999a; Pescia et al. 1999b). The ability to measure such fast SLR data on amorphous Si and copper-chromium-tin spinel led to an understanding of the role of exchange interaction in affecting spin-lattice relaxation, while the data on polymer resins doped with rare-earth ions provided evidence of spin-fracton relaxation (Pescia et al., 1999a, b). But such fast SLR times are not measurable by the most commonly used techniques of saturation- and inversion-recovery (Poole, 1982; Alger, 1968), which only measure spin-lattice relaxation times longer than 10-6 s. A summary of relevant experimental data is presented in Table 1.

Bioactivities and chemical constituents of a Vietnamese medicinal plant Che Vang, Jasminum subtriplinerve Blume (Oleaceae).

Science.gov (United States)

Ngan, Dai Hue; Hoai, Ho Thi Cam; Huong, Le Mai; Hansen, Poul Erik; Vang, Ole

2008-01-01

Five crude extracts were made from leaves and stems of Jasminum subtriplinerve Blume (Oleaceae) and investigated for antimicrobial, antioxidant and cytotoxic activities. The extractions were done with petroleum ether, ethyl acetate, ethanol, methanol or water. All extracts exhibited anti-bacterial activity except the water fraction. On the other hand, all extracts exhibit antioxidant activity except the petroleum ether fraction using the DPPH radical scavenging assay. Only the petroleum ether fraction showed a cytotoxicity activity against tested cell-lines, Hep-G2 and RD with IC(50) values of 19.2 and 20 microg mL(-1), respectively. From the petroleum ether and ethyl acetate extracts, two triterpenes namely 3beta-acetyl-oleanolic acid and lup-20-en-3beta-ol and a sterol, stigmast-5-en-3beta-ol were isolated. The structure of those compounds were elucidated by spectrometric methods IR, MS, 1D-NMR, 2D-NMR and simulated ACD/NMR spectra. The data presented here indicate that J. subtriplinerve do contain compounds with interesting biological activity.

Spin observables in p-barp → ΛΛ and density-matrix constraints

International Nuclear Information System (INIS)

Elchikh, Mokhtar; Richard, Jean-Marc

2005-01-01

The positivity conditions of the spin density matrix constrain the spin observables of the reaction p-barp → Λ-barΛ, leading to model-independent, non-trivial inequalities. The formalism is briefly presented and examples of inequalities are provided

Thermodynamic analysis of the tetragonal to monoclinic transformation in a constrained zirconia microcrystal

International Nuclear Information System (INIS)

Garvie, R.C.

1985-01-01

A thermodynamic analysis was made of a simple model comprising a transforming t-ZrO 2 microcrystal of size d constrained in a matrix subjected to a hydrostatic tensile stress field. The field generated a critical size range such that a t-particle transformed if dsub(cl) < d < dsub(cu). The lower limit dsub(cl) exists because at this point the maximum energy (supplied by the applied stress) which can be taken up by the crystal is insufficient to drive the transformation. The upper limit dsub(cu) is a consequence of the microcrystal being so large that it transforms spontaneously when the material is cooled to room temperature. Using the thermodynamic (Griffith) approach and assuming that transformation toughening is due to the dilational strain energy, this mechanism accounted for about one-third of the total observed effective surface energy in a peak-aged Ca-PSZ alloy. (author)

Spin Caloritronic Transport of 1,3,5-Triphenylverdazyl Radical

International Nuclear Information System (INIS)

Wu Qiu-Hua; Zhao Peng; Liu De-Sheng

2016-01-01

We investigate theoretically the spin caloritronic transport properties of a stable 1,3,5-triphenylverdazyl (TPV) radical sandwiched between Au electrodes through different connection fashions. Obvious spin Seebeck effect can be observed in the para-connection fashion. Furthermore, a pure spin current and a completely spin-polarized current can be realized by tuning the gate voltage. Furthermore, a 100% spin polarization without the need of gate voltage can be obtained in the meta-connection fashion. These results demonstrate that TPV radical is a promising material for spin caloritronic and spintronic applications. (paper)

Analytical Techniques and Pharmacokinetics of Gastrodia elata Blume and Its Constituents.

Science.gov (United States)

Wu, Jinyi; Wu, Bingchu; Tang, Chunlan; Zhao, Jinshun

2017-07-08

Gastrodia elata Blume ( G. elata ), commonly called Tianma in Chinese, is an important and notable traditional Chinese medicine (TCM), which has been used in China as an anticonvulsant, analgesic, sedative, anti-asthma, anti-immune drug since ancient times. The aim of this review is to provide an overview of the abundant efforts of scientists in developing analytical techniques and performing pharmacokinetic studies of G. elata and its constituents, including sample pretreatment methods, analytical techniques, absorption, distribution, metabolism, excretion (ADME) and influence factors to its pharmacokinetics. Based on the reported pharmacokinetic property data of G. elata and its constituents, it is hoped that more studies will focus on the development of rapid and sensitive analytical techniques, discovering new therapeutic uses and understanding the specific in vivo mechanisms of action of G. elata and its constituents from the pharmacokinetic viewpoint in the near future. The present review discusses analytical techniques and pharmacokinetics of G. elata and its constituents reported from 1985 onwards.

The magnetic properties of a mixed spin-1/2 and spin-1 Heisenberg ferrimagnetic system on a two-dimensional square lattice

Energy Technology Data Exchange (ETDEWEB)

Hu, Ai-Yuan, E-mail: huaiyuanhuyuanai@126.com [School of Physics and Electronic Engineering, Chongqing Normal University, Chongqing 401331 (China); Zhang, A.-Jie [Military Operational Research Teaching Division of the 4th Department, PLA Academy of National Defense Information, Wuhan 430000 (China)

2016-02-01

The magnetic properties of a mixed spin-1/2 and spin-1 Heisenberg ferrimagnetic system on a two-dimensional square lattice are investigated by means of the double-time Green's function technique within the random phase decoupling approximation. The role of the nearest-, next-nearest-neighbors interactions and the exchange anisotropy in the Hamiltonian is explored. And their effects on the critical and compensation temperature are discussed in detail. Our investigation indicates that both the next-nearest-neighbor interactions and the anisotropy have a great effect on the phase diagram. - Highlights: • Spin-1/2 and spin-1 ferrimagnetic model is examined. • Green's function technique is used. • The role of the nearest-, next-nearest-neighbors interactions and the exchange anisotropy in the Hamiltonian is explored. • The next-nearest-neighbor interactions and the anisotropy have a great effect on the phase diagram.

Moving Griffith crack in an orthotropic strip with punches at boundary faces

Directory of Open Access Journals (Sweden)

S. Mukherjee

2005-01-01

Full Text Available Integral transform technique is employed to solve the elastodynamic problem of steady-state propagation of a Griffith crack centrally situated along the midplane of orthotropic strip of finite thickness 2h and subjected to point loading with centrally situated moving punches under constant pressure along the boundaries of the layer. The problem is reduced to the solution of a pair of simultaneous singular integral equations with Cauchy-type singularities which have finally been solved through the finite Hilbert transform technique. For large h, analytical expression for the stress intensity factor at the crack tip is obtained. Graphical plots of the numerical results are also presented.

Probing spin-1 diquarks in deep inelastic structure functions

International Nuclear Information System (INIS)

Fredriksson, S.; Jaendel, M.; Larsson, T.

1983-01-01

Within the scope of a new diquark model for deep inelastic structure functions presented by us recently we use the existing data on F 1 sup(ep)(x,Q 2 ) to learn about the admixture of spin-1 diquarks in nucleons. It turns out that they are so rare, heavy and extended compared to spin-0 diquarks that they are presumably accidental and not dynamical. Their number and form factors can be understood qualitatively within this picture. Still, the spin-1 diquarks give interesting structures in data and, together with quarks and spin-0 diquarks, carry enough momentum to account for the full nucleon energy. A gluon component is hence not needed in the nucleon. (orig.)

Spin observables in antiproton-proton to AntiLambda-Lambda and density-matrix constraints

OpenAIRE

Elchikh, Mokhtar; Richard, Jean-Marc

2005-01-01

The positivity conditions of the spin density matrix constrain the spin observables of the reaction antiproton-proton to AntiLambda-Lambda, leading to model-independent, non-trivial inequalities. The formalism is briefly presented and examples of inequalities are provided.

Galaxy bispectrum from massive spinning particles

Science.gov (United States)

Moradinezhad Dizgah, Azadeh; Lee, Hayden; Muñoz, Julian B.; Dvorkin, Cora

2018-05-01

Massive spinning particles, if present during inflation, lead to a distinctive bispectrum of primordial perturbations, the shape and amplitude of which depend on the masses and spins of the extra particles. This signal, in turn, leaves an imprint in the statistical distribution of galaxies; in particular, as a non-vanishing galaxy bispectrum, which can be used to probe the masses and spins of these particles. In this paper, we present for the first time a new theoretical template for the bispectrum generated by massive spinning particles, valid for a general triangle configuration. We then proceed to perform a Fisher-matrix forecast to assess the potential of two next-generation spectroscopic galaxy surveys, EUCLID and DESI, to constrain the primordial non-Gaussianity sourced by these extra particles. We model the galaxy bispectrum using tree-level perturbation theory, accounting for redshift-space distortions and the Alcock-Paczynski effect, and forecast constraints on the primordial non-Gaussianity parameters marginalizing over all relevant biases and cosmological parameters. Our results suggest that these surveys would potentially be sensitive to any primordial non-Gaussianity with an amplitude larger than fNL≈ 1, for massive particles with spins 2, 3, and 4. Interestingly, if non-Gaussianities are present at that level, these surveys will be able to infer the masses of these spinning particles to within tens of percent. If detected, this would provide a very clear window into the particle content of our Universe during inflation.

The evolution of Griffiths-phase-like features and colossal magnetoresistance in La1-xCaxMnO3 (0.18 ≤ x ≤ 0.27) across the compositional metal-insulator boundary

International Nuclear Information System (INIS)

Jiang Wanjun; Zhou Xuezhi; Williams, Gwyn; Mukovskii, Y; Privezentsev, R

2009-01-01

Detailed measurements of the magnetic and transport properties of single crystals of La 1-x Ca x MnO 3 (0.18 ≤ x ≤ 0.27) are summarized, and lead to the following conclusions. While temperature-dependent (magneto-) resistance measurements narrow the compositionally modulated metal-insulator (M-I) transition to lie between 0.19 ≤ x c ≤ 0.20 in the series studied, comparisons between the latter magnetic data provide the first unequivocal demonstration that (i) the presence of Griffiths-phase-like (GP) features do not guarantee colossal magnetoresistance (CMR), while confirming (ii) that neither are the appearance of such features a prerequisite for CMR. These data also reveal that (iii) whereas continuous magnetic transitions occur for 0.18 ≤ x ≤ 0.25, the universality class of these transitions belongs to that of a nearest-neighbour 3D Heisenberg model only for x≤0.20, beyond which complications due to GP-like behaviour occur. The implications of the variation (or lack thereof) in critical exponents and particularly critical amplitudes and temperatures across the compositionally mediated M-I transition support the assertion that the dominant mechanism underlying ferromagnetism across the M-I transition changes from ferromagnetic super-exchange (SE) stabilized by orbital ordering in the insulating phase to double-exchange (DE) in the orbitally disordered metallic regime. The variations in the acoustic spin-wave stiffness, D, and the coercive field, H C , support this conclusion. These SE and DE interaction mechanisms are demonstrated to not only belong to the same universality class but are also characterized by comparable coupling strengths. Nevertheless, their percolation thresholds are manifestly different in this system.

Spin structure in high energy processes: Proceedings

Energy Technology Data Exchange (ETDEWEB)

DePorcel, L.; Dunwoodie, C. [eds.

1994-12-01

This report contains papers as the following topics: Spin, Mass, and Symmetry; physics with polarized Z{sup 0}s; spin and precision electroweak physics; polarized electron sources; polarization phenomena in quantum chromodynamics; polarized lepton-nucleon scattering; polarized targets in high energy physics; spin dynamics in storage rings and linear accelerators; spin formalism and applications to new physics searches; precision electroweak physics at LEP; recent results on heavy flavor physics from LEP experiments using 1990--1992 data; precise measurement of the left-right cross section asymmetry in Z boson production by electron-positron collisions; preliminary results on heavy flavor physics at SLD; QCD tests with SLD and polarized beams; recent results from TRISTAN at KEK; recent B physics results from CLEO; searching for the H dibaryon at Brookhaven; recent results from the compton observatory; the spin structure of the deuteron; spin structure of the neutron ({sup 3}HE) and the Bjoerken sum rule; a consumer`s guide to lattice QCD results; top ten models constrained by b {yields} sy; a review of the Fermilab fixed target program; results from the D0 experiment; results from CDF at FNAL; quantum-mechanical suppression of bremsstrahlung; report from the ZEUS collaboration at HERA; physics from the first year of H1 at HERA, and hard diffraction. These papers have been cataloged separately elsewhere.

Spin structure in high energy processes: Proceedings

International Nuclear Information System (INIS)

DePorcel, L.; Dunwoodie, C.

1994-12-01

This report contains papers as the following topics: Spin, Mass, and Symmetry; physics with polarized Z 0 s; spin and precision electroweak physics; polarized electron sources; polarization phenomena in quantum chromodynamics; polarized lepton-nucleon scattering; polarized targets in high energy physics; spin dynamics in storage rings and linear accelerators; spin formalism and applications to new physics searches; precision electroweak physics at LEP; recent results on heavy flavor physics from LEP experiments using 1990--1992 data; precise measurement of the left-right cross section asymmetry in Z boson production by electron-positron collisions; preliminary results on heavy flavor physics at SLD; QCD tests with SLD and polarized beams; recent results from TRISTAN at KEK; recent B physics results from CLEO; searching for the H dibaryon at Brookhaven; recent results from the compton observatory; the spin structure of the deuteron; spin structure of the neutron ( 3 HE) and the Bjoerken sum rule; a consumer's guide to lattice QCD results; top ten models constrained by b → sy; a review of the Fermilab fixed target program; results from the D0 experiment; results from CDF at FNAL; quantum-mechanical suppression of bremsstrahlung; report from the ZEUS collaboration at HERA; physics from the first year of H1 at HERA, and hard diffraction. These papers have been cataloged separately elsewhere

KARAKTERISTIK MORFOLOGI SERTA PERKEMBANGAN FIG NYAWAI (Ficus variegata Blume DI KEBUN RAYA CIBODAS

Directory of Open Access Journals (Sweden)

Agus Astho Pramono

2015-12-01

Full Text Available Nyawai (Ficus variegata Blume merupakan salah satu jenis pohon yang memiliki prospek yang baik untuk hutan tanaman. Informasi tentang aspek biologi reproduksinya masih terbatas. Penelitian ini bertujuan untuk mengetahui karakteristik morfologi bunga dan buah nyawai, serta tahapan perkembangan fig. Penelitian dilakukan di Kebun Raya Cibodas, Jawa Barat. Kegiatan penelitian meliputi: 1 pengamatan morfologi bunga dan buah, dan 2 pengamatan perkembangan fig. Hasil penelitian menunjukkan bahwa karakteristik morfologi fig nyawai yang dijumpai di Kebun Raya Cibodas, memiliki variasi yang tinggi dalam hal ukuran dan warna. Berdasarkan karakteristik morfologi bunga, secara individual ditemui dua tipe pohon yang mencirikan sebagai pohon menghasilkan bunga jantan dan penghasil bunga betina. Perbedaan antara tahap bunga, buah muda, dan buah matang tidak dapat dibakukan berdasarkan karakteristik morfologi eksternal dari fig. Tingkat kematangan buah nyawai dapat dilakukan dengan membelah fig. Nyawai tahap kuncup bunga berakhir sekitar 6-11 hari setelah munculya tunas fig, dan tahap bunga berakhir 11-26 hari. Perkembangan kuncup bunga menjadi buah yang matang memakan waktu sekitar 2-3 bulan. Hasil penelitian menyarankan untuk tidak mengumpulkan benih dari fig yang berukuran kecil, meskipun mereka memiliki karakteristik fisik fig yang matang.

Green function study of a mixed spin-((3)/(2)) and spin-((1)/(2)) Heisenberg ferrimagnetic model

International Nuclear Information System (INIS)

Li Jun; Wei Guozhu; Du An

2004-01-01

The magnetic properties of a mixed spin-((3)/(2)) and spin-((1)/(2)) Heisenberg ferrimagnetic system on a square lattice are investigated theoretically by a multisublattice Green-function technique which takes into account the quantum nature of Heisenberg spins. This model can be relevant for understanding the magnetic behavior of the new class of organometallic materials that exhibit spontaneous magnetic moments at room temperature. We discuss the spontaneous magnetic moments and the finite-temperature phase diagram. We find that there is no compensation point at finite temperature when only the nearest-neighbor interaction and the single-ion anisotropy are included. When the next-nearest-neighbor interaction between spin-((1)/(2)) is taken into account and exceeds a minimum value, a compensation point appears and it is basically unchanged for other values in Hamiltonian fixed. The next-nearest-neighbor interaction between spin-((3)/(2)) has the effect of changing the compensation temperature

Effective electric and magnetic polarizabilities of pointlike spin-1/2 particles

OpenAIRE

Silenko, A. J.

2014-01-01

Effective electric and magnetic polarizabilities of pointlike spin-1/2 particles possesing an anomalous magnetic moment are calculated with the transformation of an initial Hamiltonian to the Foldy-Wouthuysen representation. Polarizabilities of spin-1/2 and spin-1 particles are compared.

Engineering the Eigenstates of Coupled Spin-1/2 Atoms on a Surface.

Science.gov (United States)

Yang, Kai; Bae, Yujeong; Paul, William; Natterer, Fabian D; Willke, Philip; Lado, Jose L; Ferrón, Alejandro; Choi, Taeyoung; Fernández-Rossier, Joaquín; Heinrich, Andreas J; Lutz, Christopher P

2017-12-01

Quantum spin networks having engineered geometries and interactions are eagerly pursued for quantum simulation and access to emergent quantum phenomena such as spin liquids. Spin-1/2 centers are particularly desirable, because they readily manifest coherent quantum fluctuations. Here we introduce a controllable spin-1/2 architecture consisting of titanium atoms on a magnesium oxide surface. We tailor the spin interactions by atomic-precision positioning using a scanning tunneling microscope (STM) and subsequently perform electron spin resonance on individual atoms to drive transitions into and out of quantum eigenstates of the coupled-spin system. Interactions between the atoms are mapped over a range of distances extending from highly anisotropic dipole coupling to strong exchange coupling. The local magnetic field of the magnetic STM tip serves to precisely tune the superposition states of a pair of spins. The precise control of the spin-spin interactions and ability to probe the states of the coupled-spin network by addressing individual spins will enable the exploration of quantum many-body systems based on networks of spin-1/2 atoms on surfaces.

Constraining the electric dipole photon strength function in {sup 130}Te

Energy Technology Data Exchange (ETDEWEB)

Isaak, J.; Loeher, B.; Savran, D.; Silva, J. [ExtreMe Matter Institute EMMI and Research Division, Darmstadt (Germany); FIAS, Frankfurt (Germany); Ahmed, M.W.; Kelley, J.H.; Tornow, W.; Weller, H.R. [Department of Physics, Duke University, TUNL (United States); Beller, J.; Pietralla, N.; Romig, C.; Zweidinger, M. [Institut fuer Kernphysik, TU Darmstadt (Germany); Glorius, J.; Sonnabend, K. [Institut fuer Angewandte Physik, Goethe-Universitaet Frankfurt (Germany); Krticka, M. [Faculty of Mathematics and Physics, Charles University, Prague (Czech Republic); Rusev, G. [Chemistry Division, LANL (United States); Scheck, M. [School of Engineering, University of the West of Scotland (United Kingdom); Tonchev, A.P. [Physics Division, LLNL (United States)

2014-07-01

The decay properties of photo-excited states in {sup 130}Te have been investigated by means of Nuclear Resonance Fluorescence experiments at the Darmstadt High Intensity Photon Setup (DHIPS) and the High Intensity γ-ray Source (HIγS). The combination of continuous-energy bremsstrahlung on the one hand and the quasi-monoenergetic and linearly polarized photon beam on the other enables a detailed insight into the photoabsorption cross section and the decay behavior of spin-1 states. Comparing these results to simulations within the statistical model allow for constraining the electric dipole photon strength function (E1-PSF). Results are presented and discussed.

Predicting Near Edge X-ray Absorption Spectra with the Spin-Free Exact-Two-Component Hamiltonian and Orthogonality Constrained Density Functional Theory.

Science.gov (United States)

Verma, Prakash; Derricotte, Wallace D; Evangelista, Francesco A

2016-01-12

Orthogonality constrained density functional theory (OCDFT) provides near-edge X-ray absorption (NEXAS) spectra of first-row elements within one electronvolt from experimental values. However, with increasing atomic number, scalar relativistic effects become the dominant source of error in a nonrelativistic OCDFT treatment of core-valence excitations. In this work we report a novel implementation of the spin-free exact-two-component (X2C) one-electron treatment of scalar relativistic effects and its combination with a recently developed OCDFT approach to compute a manifold of core-valence excited states. The inclusion of scalar relativistic effects in OCDFT reduces the mean absolute error of second-row elements core-valence excitations from 10.3 to 2.3 eV. For all the excitations considered, the results from X2C calculations are also found to be in excellent agreement with those from low-order spin-free Douglas-Kroll-Hess relativistic Hamiltonians. The X2C-OCDFT NEXAS spectra of three organotitanium complexes (TiCl4, TiCpCl3, TiCp2Cl2) are in very good agreement with unshifted experimental results and show a maximum absolute error of 5-6 eV. In addition, a decomposition of the total transition dipole moment into partial atomic contributions is proposed and applied to analyze the nature of the Ti pre-edge transitions in the three organotitanium complexes.

Phase-space spinor amplitudes for spin-1/2 systems

International Nuclear Information System (INIS)

Watson, P.; Bracken, A. J.

2011-01-01

The concept of phase-space amplitudes for systems with continuous degrees of freedom is generalized to finite-dimensional spin systems. Complex amplitudes are obtained on both a sphere and a finite lattice, in each case enabling a more fundamental description of pure spin states than that previously given by Wigner functions. In each case the Wigner function can be expressed as the star product of the amplitude and its conjugate, so providing a generalized Born interpretation of amplitudes that emphasizes their more fundamental status. The ordinary product of the amplitude and its conjugate produces a (generalized) spin Husimi function. The case of spin-(1/2) is treated in detail, and it is shown that phase-space amplitudes on the sphere transform correctly as spinors under rotations, despite their expression in terms of spherical harmonics. Spin amplitudes on a lattice are also found to transform as spinors. Applications are given to the phase space description of state superposition, and to the evolution in phase space of the state of a spin-(1/2) magnetic dipole in a time-dependent magnetic field.

The Spin Vector of (832) Karin

Science.gov (United States)

Slivan, Stephen M.; Molnar, L. A.

2010-10-01

We observed rotation lightcurves of Koronis family and Karin cluster member (832) Karin during its four consecutive apparitions in 2006-2009, and combined the new observations with previously published lightcurves to determine its spin vector orientation and preliminary model shape. Karin is a prograde rotator with a period of 18.352 h, spin obliquity near 41°, and pole ecliptic longitude near either 51° or 228°. Although the two ambiguous pole solutions are near the clustered pole solutions of four Koronis family members whose spins are thought to be trapped in a spin-orbit resonance (Vokrouhlický et al., 2003), Karin does not seem to be trapped in the resonance; this is consistent with the expectation that the 6 My age of Karin (Nesvorný et al., 2002) is too young for YORP torques to have modified its spin since its formation. The spin vector and shape results for Karin will constrain family formation models that include spin properties, and we discuss the Karin results in the context of the other members of the Karin cluster, the Karin parent body, and the parent body's siblings in the Koronis family.

Effective Floquet Hamiltonian for spin I = 1 in magic angle spinning ...

Indian Academy of Sciences (India)

WINTEC

Floquet Hamiltonians; contact transformations in NMR; Spin-1 MAS NMR; effective Ham- iltonians. 1. Introduction. Solid state nuclear magnetic resonance spectroscopy is an important technique to study structures, dyna- mics and electric charge distribution around nuclei in solids. It is also more difficult to perform and ana-.

A new species of the ant genus Bothriomyrmex Emery, 1869 (Hymenoptera: Formicidae from the Caribbean region

Directory of Open Access Journals (Sweden)

Matthew Prebus

2016-07-01

Full Text Available Bothriomyrmex enigmaticus sp. nov. is described from the island of Hispañola based on one nest collection. This is the first collection of the genus Bothriomyrmex (Emery, 1869 from the Caribbean region, and the second species to be described from the Americas. While sharing several characters with B. paradoxus (Dubovikoff & Longino, 2004 from Costa Rica and Honduras, B. enigmaticus sp. nov. diverges in several key characters, including palp formula. However, a morphometric comparison to Palearctic species of the tribe Bothriomyrmecini suggests affinities to B. paradoxus, Chronoxenus wroughtoni (Forel, 1895 of the eastern Palearctic, and to a lesser extent an undescribed species of Arnoldius (Dubovikoff, 2005 from Australia and B. corsicus (Santschi,1923 of the western Palearctic.

Symmetric coupling of four spin-1/2 systems

Science.gov (United States)

Suzuki, Jun; Englert, Berthold-Georg

2012-06-01

We address the non-binary coupling of identical angular momenta based upon the representation theory for the symmetric group. A correspondence is pointed out between the complete set of commuting operators and the reference-frame-free subsystems. We provide a detailed analysis of the coupling of three and four spin-1/2 systems and discuss a symmetric coupling of four spin-1/2 systems.

Micropropagation of Codiaeum variegatum (L.) Blume and regeneration induction via adventitious buds and somatic embryogenesis.

Science.gov (United States)

Radice, Silvia

2010-01-01

Codiaeum variegatum (L) Blume cv. "Corazon de oro" and cv. "Norma" are successfully micropropagated when culture are initiated with explants taken from newly sprouted shoots. The establishment and multiplication steps are possible when 1 mg/L BA or 1 mg/L IAA and 3 mg/L 2iP are added to MS medium, according to the cultivar respectively selected.Adventive organogenesis and somatic embryogenesis are induced from leaf explants taken from in vitro buds of croton. On leaf-sectioned of "Corazon de oro" cultured in vitro, 1 mg/L BA stimulates continuous somatic embryos development and induces some shoots too. Replacing BA with 1 mg/L TDZ induces up to 100% bud regeneration in the same explants. On the other hand, leaf-sectioned of C. variegatum cv. Norma does not start somatic embryo differentiation if 1 mg/L TDZ is not added to the MS basal medium. Incipient callus is observed after 30 days of culture, and then, subculture to MS with 1 mg/L BA allows the same process to show on the "Corazon de oro" cultivar. Somatic embryos show growth arrest that is partially overcome by transfer to hormone-free basal medium with activated charcoal. Root induction is possible on basal medium plus 1 mg/L IBA. Plantlets in the greenhouse have variegated leaves true-to-type.

Magnetic exchange couplings from constrained density functional theory: an efficient approach utilizing analytic derivatives.

Science.gov (United States)

Phillips, Jordan J; Peralta, Juan E

2011-11-14

We introduce a method for evaluating magnetic exchange couplings based on the constrained density functional theory (C-DFT) approach of Rudra, Wu, and Van Voorhis [J. Chem. Phys. 124, 024103 (2006)]. Our method shares the same physical principles as C-DFT but makes use of the fact that the electronic energy changes quadratically and bilinearly with respect to the constraints in the range of interest. This allows us to use coupled perturbed Kohn-Sham spin density functional theory to determine approximately the corrections to the energy of the different spin configurations and construct a priori the relevant energy-landscapes obtained by constrained spin density functional theory. We assess this methodology in a set of binuclear transition-metal complexes and show that it reproduces very closely the results of C-DFT. This demonstrates a proof-of-concept for this method as a potential tool for studying a number of other molecular phenomena. Additionally, routes to improving upon the limitations of this method are discussed. © 2011 American Institute of Physics

Novel LMNA Mutation in a Taiwanese Family with Autosomal Dominant Emery-Dreifuss Muscular Dystrophy

Directory of Open Access Journals (Sweden)

Wen-Chen Liang

2007-01-01

Full Text Available Emery-Dreifuss muscular dystrophy (EDMD is characterized by early-onset contractures, slowly progressive weakness, and muscle wasting in humeroperoneal muscles, and adult-onset cardiomyopathy with conduction block. We analyzed blood samples from an EDMD family, including a mother and two daughters, and found a novel mutation in codon 520 in exon 9 of the lamin A/C (LMNA gene, resulting in a substitution of tryptophan (W by glycine (G in all three patients. The mother died after a stroke-like episode at the age of 43. The elder sister received pacemaker implantation, which improved symptoms of exercise intolerance and dizziness. These cases illustrate the necessity of correct diagnosis, evaluation, and follow-up of cardiac problems due to the wide clinical spectrum and high prevalence of cardiac conduction block in patients with autosomal dominant EDMD. [J Formos Med Assoc 2007;106(2 Suppl:S27-S31

Kinematics of semiclassical spin and spin fiber bundle associated with so(n) Lie-Poisson manifold

International Nuclear Information System (INIS)

Deriglazov, A A

2013-01-01

We describe geometric construction underlying the Lagrangian actions for non-Grassmann spinning particles proposed in our recent works. If we discard the spatial variables (the case of frozen spin), the problem reduces to formulation of a variational problem for Hamiltonian system on a manifold with so(n) Lie-Poisson bracket. To achieve this, we identify dynamical variables of the problem with coordinates of the base of a properly constructed fiber bundle. In turn, the fiber bundle is embedded as a surface into the phase space equipped with canonical Poisson bracket. This allows us to formulate the variational problem using the standard methods of Dirac theory for constrained systems.

Selective substitution in orbital domains of a low doped manganite: an investigation from Griffiths phenomenon and modification of glassy features

International Nuclear Information System (INIS)

Mukherjee, K; Banerjee, A

2009-01-01

An effort is made to study the contrast in magnetic behavior resulting from minimal disorder introduced by substitution of 2.5% Ga or Al in Mn site of La 0.9 Sr 0.1 MnO 3 . It is considered that Ga or Al selectively create disorder within the orbital domains or on its walls, causing enhancement of Griffiths phase (GP) singularity for the former and disappearance of it in the latter case. It is shown that Ga replaces Mn 3+ , which is considered to be concentrated within the domains, whereas Al replaces Mn 4+ , which is segregated on the hole-rich walls, without causing any significant effect on structure or ferromagnetic transition temperatures. Thus, it is presumed that the effect of disorder created by Ga extends across the bulk of the domain having correlation over a similar length scale, resulting in enhancement of the GP phenomenon. In contrast, the effect of disorder created by Al remains restricted to the walls, resulting in the modification of the dynamics arising from the domain walls and suppresses the GP. Moreover, contrasting features are observed in the low temperature region of the compounds; a re-entrant spin-glass-like behavior is observed in the Ga-doped sample, while the observed characteristics for the Al-doped sample are ascribed only to modified domain wall dynamics with the absence of any glassy phase. Distinctive features in third-order susceptibility measurements reveal that the magnetic ground state of the entire series comprises of orbital domain states. These observations bring out the role of the nature of disorder on the GP phenomenon and also reconfirms the character of self-organization in low doped manganites.

Low-temperature spin transport in a S = 1 one-dimensional antiferromagnet

International Nuclear Information System (INIS)

Pires, A S T; Lima, L S

2009-01-01

We study spin transport in the insulating antiferromagnet with S = 1 in one dimension. The spin conductivity is calculated, at zero temperature, using a modified spin wave theory and the Kubo formalism, within the ladder approximation. Two-magnon processes provide the dominant contribution to the spin conductivity. At finite temperature, free magnons are activated, and turn the system into a perfect spin conductor, i.e., the spin conductivity has a Drude form with infinite scattering time.

Ladder Ising spin configurations. Pt. 1. Heat capacity

International Nuclear Information System (INIS)

Mejdani, R.; Lambros, A.

1996-01-01

We consider a ladder Ising spin model (with two coupled Ising spin chains), characterized by two couplings (interchain and intrachain couplings), to study in detail, in an analytical way, its thermal behaviour and particularly the variation of the specific heat versus temperature, the ratio of interaction constants, and the magnetic field. It is interesting that when the competition between interchain and intrachain interactions is strong the specific heat exhibits a double peak and when the competition is not so strong the specific heat has a single peak. Further, without entering into details, we give, in a numerical way, some similar results for more complicated ladder configurations (with more than two linear Ising chains). The spin-1/2 ladders or systems of spin chains may be realized in nature by vanadyl pyrophosphate ((VO) 2 P 2 O 7 ) or similar materials. All these intermediate systems are today important to gain further insight into the physics of one-dimensional spin chains and two-dimensional high-T c spin systems, both of which have shown interesting and unusual magnetic and superconducting properties. It is plausible that experimental and theoretical studies of ladders may lead to other interesting physical phenomena. (orig.)

Spin dynamics of paramagnetic centers with anisotropic g tensor and spin of 1/2

Science.gov (United States)

Maryasov, Alexander G.; Bowman, Michael K.

2012-08-01

The influence of g tensor anisotropy on spin dynamics of paramagnetic centers having real or effective spin of 1/2 is studied. The g anisotropy affects both the excitation and the detection of EPR signals, producing noticeable differences between conventional continuous-wave (cw) EPR and pulsed EPR spectra. The magnitudes and directions of the spin and magnetic moment vectors are generally not proportional to each other, but are related to each other through the g tensor. The equilibrium magnetic moment direction is generally parallel to neither the magnetic field nor the spin quantization axis due to the g anisotropy. After excitation with short microwave pulses, the spin vector precesses around its quantization axis, in a plane that is generally not perpendicular to the applied magnetic field. Paradoxically, the magnetic moment vector precesses around its equilibrium direction in a plane exactly perpendicular to the external magnetic field. In the general case, the oscillating part of the magnetic moment is elliptically polarized and the direction of precession is determined by the sign of the g tensor determinant (g tensor signature). Conventional pulsed and cw EPR spectrometers do not allow determination of the g tensor signature or the ellipticity of the magnetic moment trajectory. It is generally impossible to set a uniform spin turning angle for simple pulses in an unoriented or 'powder' sample when g tensor anisotropy is significant.

Recent Spin Pump Experiments on Superfluid 3He-A1

Science.gov (United States)

Yamaguchi, A.; Kamada, N.; Motoyama, G.; Sumiyama, A.; Aoki, Y.; Okuda, Y.; Kubota, M.; Kojima, H.

2013-05-01

The superfluid 3He A1 phase, containing a spin-polarized condensate allows us to explore the dynamics of superfluid spin current. In the mechano-spin effect (MSE), a mechanically applied pressure gradient and a superleak-spin filter enable one to directly boost spin polarization of 3He in a small chamber. We are developing new apparatus for achieving greater enhancement of spin density. A development of a new-type 3He-hydraulic actuator has been already reported. We present here the construction of new-type of superleak-spin-filter made of packed powder aluminum oxide (referred as PAP-SL). The PAP-SL is popular in the study of superfluid 4He, but has not been established for that of the superfluid 3He. The attempt to construct the PAP-SL for the spin pump experiment was made by using aluminum oxide powder with nominal 1 μm powder diameter and with packing fraction of 40 %. Before executing the experiment, the nuclear demagnetization cryostat of ISSP, Univ. Tokyo which has been used for this experimental activity, was heavily damaged by the 2011 Great East Japan (Higashi Nihon) Earthquake. The repair work and earthquake damage protection strengthening has just been accomplished.

Prima facie evidence against spin-two Higgs impostors

OpenAIRE

Ellis, John; Sanz, Veronica; You, Tevong

2013-01-01

The new particle X recently discovered by the ATLAS and CMS Collaborations is widely expected to have spin zero, but this remains to be determined. The leading alternative is that X has spin two, presumably with graviton-like couplings. We show that measurements of the X particle to pairs of vector bosons constrain such scenarios. In particular, a graviton-like Higgs impostor in scenarios with a warped extra dimension of AdS type is prima facie excluded, principally because they predict too s...

Organic Additives Improves the in Vitro Growth of Native Orchid Vanda helvola Blume

Directory of Open Access Journals (Sweden)

Devina DAVID

2015-06-01

Full Text Available In vitro seed germination has been proven to be the most efficient technique to propagate orchid. The application of this aseptic technique has contributed to conservation of many endangered orchid species. In this study, undehisced capsules of Vanda helvola Blume were collected from Orchid Conservation Centre in Lagud Sebrang Agriculture Park, after 120 days from hand pollination and aseptically cultured on three types of basal media such as Murashige and Skoog (MS, Knudson C (KC and Vacin and Went (VW. After 90 days of culture, 66.40 ± 4.14% of seeds successfully germinated on KC medium. The effect of organic additives such as tomato juice, coconut water, peptone and yeast extract at different level of concentrations in KC basal medium were also tested on seed germination and seedling development of this native orchid. After 90 days of culture, over 90% of seeds were tremendously germinated on KC medium supplemented with 10% or 15% (v/v of tomato juice. The incorporation of peptone at 0.1% (w/v in KC basal media promoted rapid development of protocorm to seedling. Seedlings on this treatment produced an average of three leaves and two roots after 90 days of culture and were successfully acclimatized.

The Extreme Spin of the Black Hole Cygnus X-1

Science.gov (United States)

Gou, Lijun; McClintock, Jeffrey E.; Reid, Mark J.; Orosz, Jerome A.; Steiner, James F.; Narayan, Ramesh; Xiang, Jingen; Remillard, Ronald A.; Arnaud, Keith A.; Davis, Shane W.

2011-01-01

Remarkably, an astronomical black hole is completely described by the two numbers that specify its mass and its spin. Knowledge of spin is crucial for understanding how, for example, black holes produce relativistic jets. Recently, it has become possible to measure the spins of black holes by focusing on the very inner region of an accreting disk of hot gas orbiting the black hole. According to General Relativity (GR), this disk is truncated at an inner radius 1 that depends only on the mass and spin of the black hole. We measure the radius of the inner edge of this disk by fitting its continuum X-ray spectrum to a fully relativistic model. Using our measurement of this radius, we deduce that the spin of Cygnus X-1 exceeds 97% of the maximum value allowed by GR.

Magnetic field dependence of Griffith phase and magnetocaloric effect in Ca0.85Dy0.15MnO3

Science.gov (United States)

Nag, Ripan; Sarkar, Bidyut; Pal, Sudipta

2018-03-01

Temperature and Magnetic field dependent magnetization properties of electron doped polycrystalline sample Ca0.85Dy0.15MnO3 (CDMO) prepared by solid state reaction method have been studied. The sample undergoes ferromagnetic to paramagnetic phase transition at about 111k. From the study of magnetic properties in terms of Arrot plots it is observed that the phase transition is of 2nd order. The Griffith phase behavior of the sample is suppressed with the increase of the applied magnetic field strength H. We have estimated the magnetic entropy change from experimental magnetization and temperature data. For a magnetic field change of 8000 Oe, the maximum value of magnetic entropy change arrives at a value of 1.126 J-kg-1 k-1 in this magnetocaloric material.

Dark matter, constrained minimal supersymmetric standard model, and lattice QCD.

Science.gov (United States)

Giedt, Joel; Thomas, Anthony W; Young, Ross D

2009-11-13

Recent lattice measurements have given accurate estimates of the quark condensates in the proton. We use these results to significantly improve the dark matter predictions in benchmark models within the constrained minimal supersymmetric standard model. The predicted spin-independent cross sections are at least an order of magnitude smaller than previously suggested and our results have significant consequences for dark matter searches.

Higher-spin-matter gauge interactions in 2+1 dimensions

International Nuclear Information System (INIS)

Vasiliev, M.A.

1997-01-01

We discuss general properties of higher-spin gauge theories paying particular attention to specificities of higher-spin gauge interactions of massive matter fields in 2+1 dimensional space-time. The main conclusions are that the parameter of mass M appears as a module characterizing an appropriate vacuum solution of the full non-linear model and that M affects a structure of a global vacuum higher-spin symmetry which leaves invariant the chosen vacuum solution. Special attention is paid to local Lorentz symmetry as a guiding principle which fixes a form of non-linear higher-spin equations formulated as some zero-curvature conditions supplemented with non-linear constraints. (orig.)

Transform Domain Robust Variable Step Size Griffiths' Adaptive Algorithm for Noise Cancellation in ECG

Science.gov (United States)

Hegde, Veena; Deekshit, Ravishankar; Satyanarayana, P. S.

2011-12-01

The electrocardiogram (ECG) is widely used for diagnosis of heart diseases. Good quality of ECG is utilized by physicians for interpretation and identification of physiological and pathological phenomena. However, in real situations, ECG recordings are often corrupted by artifacts or noise. Noise severely limits the utility of the recorded ECG and thus needs to be removed, for better clinical evaluation. In the present paper a new noise cancellation technique is proposed for removal of random noise like muscle artifact from ECG signal. A transform domain robust variable step size Griffiths' LMS algorithm (TVGLMS) is proposed for noise cancellation. For the TVGLMS, the robust variable step size has been achieved by using the Griffiths' gradient which uses cross-correlation between the desired signal contaminated with observation or random noise and the input. The algorithm is discrete cosine transform (DCT) based and uses symmetric property of the signal to represent the signal in frequency domain with lesser number of frequency coefficients when compared to that of discrete Fourier transform (DFT). The algorithm is implemented for adaptive line enhancer (ALE) filter which extracts the ECG signal in a noisy environment using LMS filter adaptation. The proposed algorithm is found to have better convergence error/misadjustment when compared to that of ordinary transform domain LMS (TLMS) algorithm, both in the presence of white/colored observation noise. The reduction in convergence error achieved by the new algorithm with desired signal decomposition is found to be lower than that obtained without decomposition. The experimental results indicate that the proposed method is better than traditional adaptive filter using LMS algorithm in the aspects of retaining geometrical characteristics of ECG signal.

In Vitro Contracture Test Results and Anaesthetic Management of a Patient with Emery-Dreifuss Muscular Dystrophy for Cardiac Transplantation

Directory of Open Access Journals (Sweden)

Frank Schuster

2012-01-01

Full Text Available Emery-Dreifuss muscular dystrophy (EDMD is a hereditary neuromuscular disorder characterized by slowly progressive muscle weakness, early contractures, and dilated cardiomyopathy. We reported an uneventful general anaesthesia using total intravenous anaesthesia (TIVA for cardiac transplantation in a 19-year-old woman suffering from EDMD. In vitro contracture test results of two pectoralis major muscle bundles of the patient suggest that exposition to triggering agents does not induce a pathological sarcoplasmic calcium release in the lamin A/C phenotype. However, due to the lack of evidence in the literature, we would recommend TIVA for patients with EDMD if general anaesthesia is required.

Spin tunnelling dynamics for spin-1 Bose-Einstein condensates in a swept magnetic field

International Nuclear Information System (INIS)

Wang Guanfang; Fu Libin; Liu Jie

2008-01-01

We investigate the spin tunnelling of spin-1 Bose-Einstein condensates in a linearly swept magnetic field with a mean-field treatment. We focus on the two typical alkali Bose atoms 87 Rb and 23 Na condensates and study their tunnelling dynamics according to the sweep rates of the external magnetic fields. In the adiabatic (i.e. slowly sweeping) and sudden (i.e. fast sweeping) limits, no tunnelling is observed. For the case of moderate sweep rates, the tunnelling dynamics is found to be very sensitive to the sweep rates, so the plots of tunnelling probability versus sweep rate only become resolvable at a resolution of 10 -4 G s -1 . Moreover, a conserved quantity standing for the magnetization in experiments is found to affect dramatically the dynamics of the spin tunnelling. Theoretically we have given a complete interpretation of the above findings, and our studies could stimulate the experimental study of spinor Bose-Einstein condensates

Spin frustration of a spin-1/2 Ising–Heisenberg three-leg tube as an indispensable ground for thermal entanglement

International Nuclear Information System (INIS)

Strečka, Jozef; Alécio, Raphael Cavalcante; Lyra, Marcelo L.; Rojas, Onofre

2016-01-01

The spin-1/2 Ising–Heisenberg three-leg tube composed of the Heisenberg spin triangles mutually coupled through the Ising inter-triangle interaction is exactly solved in a zero magnetic field. By making use of the local conservation for the total spin on each Heisenberg spin triangle the model can be rigorously mapped onto a classical composite spin-chain model, which is subsequently exactly treated through the transfer-matrix method. The ground-state phase diagram, correlation functions, concurrence, Bell function, entropy and specific heat are examined in detail. It is shown that the spin frustration represents an indispensable ground for a thermal entanglement, which is quantified by the quantum concurrence. The specific heat displays diverse temperature dependences, which may include a sharp low-temperature peak mimicking a temperature-driven first-order phase transition. It is convincingly evidenced that this anomalous peak originates from massive thermal excitations from the doubly degenerate ground state towards an excited state with a high macroscopic degeneracy due to chiral degrees of freedom of the Heisenberg spin triangles. - Highlights: • Spin-1/2 Ising–Heisenberg three-leg tube is exactly solved in a zero magnetic field. • Thermal entanglement is only present in a frustrated part of the parameter space. • Spin frustration and thermal entanglement show antagonistic reentrance. • Specific heat may display a sharp narrow peak due to massive thermal excitations.

Spin currents of charged Dirac particles in rotating coordinates

Science.gov (United States)

Dayi, Ö. F.; Yunt, E.

2018-03-01

The semiclassical Boltzmann transport equation of charged, massive fermions in a rotating frame of reference, in the presence of external electromagnetic fields is solved in the relaxation time approach to establish the distribution function up to linear order in the electric field in rotating coordinates, centrifugal force and the derivatives. The spin and spin current densities are calculated by means of this distribution function at zero temperature up to the first order. It is shown that the nonequilibrium part of the distribution function yields the spin Hall effect for fermions constrained to move in a plane perpendicular to the angular velocity and magnetic field. Moreover it yields an analogue of Ohm's law for spin currents whose resistivity depends on the external magnetic field and the angular velocity of the rotating frame. Spin current densities in three-dimensional systems are also established.

Study of burahol (Stelechocarpus burahol (Blume Hook & Thomson as an anti-oxidative compounds containing fruit

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DJADJAT TISNADJAJA

2006-04-01

Full Text Available Burahol (Stelechocarpus burahol (Blume Hook & Thomson is one of fruit tree that originally was founded in Indonesia. Traditionally burahol is used as natural deodorance, but due to low economic value, the cultivation program of this plant species is almost abandoned. Regarding to this situation, currently this plant species could be categorized as one of endangered species. At present, economic value of this fruit is almost neglected and this is the main reason why not many people interested to cultivate this plant. In order to change the people opinion on this plant and to improve it economic value, study on the chemical content of this plant had been carried out. From the research work, it was founded that burahol fruit have a significant content of anti-oxidative compound. From the anti-oxidative analysis using DPPH (1,1-diphinil pycril hidrazil method, the lowest IC50 was showed by n-buthanol extract of flower (22.44 ppm and ethyl acetate extract of fruit (29.12 ppm. Flower part also showed low IC50 of ethyl acetate extract (35.07 ppm. Further purification through fractionation process of the plant extract was surprisingly followed by the decrease of anti-oxidative activity.

Entanglement in a two-spin (1/2, 3/2) mixed-spin Heisenberg XXZ chain with an inhomogeneous external magnetic field

International Nuclear Information System (INIS)

Guo Ketao; Liang Mingchao; Xu Hongyu; Zhu Chengbo

2010-01-01

Using the concept of negativity, we investigate the thermal entanglement of a two-spin (1/2, 3/2) mixed-spin Heisenberg XXZ chain with an inhomogeneous external magnetic field. We obtain the analytical results of entanglement of this model. For the case of uniform magnetic field, we find that the critical temperature increases with the increase of the anisotropy parameter k, and for the same couplings, the critical temperature is higher than the results of the spin-1/2 XXZ chain and (1/2, 1) mixed-spin XXZ chain. Evidence of the quantum phase transition is found, and by adjusting the inhomogeneous magnetic parameter b, one is able to obtain more entanglement at higher temperature.

Measurement of the proton spin structure function g1p

International Nuclear Information System (INIS)

Pussieux, T.

1994-10-01

In order to check the Bjorken sum rule and confirm the EMC surprising conclusion on the spin structure of the proton, the measurement of the spin structure function of the proton has been performed by the Spin Muon Collaboration via the polarized muon nucleon deep inelastic scattering. The results of the 1993 run are presented within a kinematical range of 0.003 2 = 10 GeV 2 . The first moment of the polarized spin structure function g 1 p is found to be two standard deviations below the Ellis-Jaffe sum rule. Assuming SU(3) for hyperons β decays, the quark spin contribution to the proton spin is extracted. Combining all available data on proton, neutron and deuton, The Bjorken sum rule is confirmed within 10%. (author). 25 refs., 3 figs., 2 tabs

Spin-1 diquark contributing to the formation of tetraquarks in light mesons

International Nuclear Information System (INIS)

Kim, Hungchong; Cheoun, Myung-Ki; Kim, K.S.

2017-01-01

We apply a mixing framework to the light-meson systems and examine tetraquark possibility in the scalar channel. In the diquark-antidiquark model, a scalar diquark is a compact object when its color and flavor structures are in (anti 3_c, anti 3_f). Assuming that all the quarks are in an S-wave, the spin-0 tetraquark formed out of this scalar diquark has only one spin configuration, vertical stroke J,J_1_2,J_3_4 right angle = vertical stroke 000 right angle, where J is the spin of the tetraquark, J_1_2 the diquark spin, J_3_4 the antidiquark spin. In this construction of the scalar tetraquark, we notice that another compact diquark with spin-1 in (6_c, anti 3_f) can be used although it is less compact than the scalar diquark. The spin-0 tetraquark constructed from this vector diquark leads to the spin configuration vertical stroke J,J_1_2,J_3_4 right angle = vertical stroke 011 right angle. The two configurations, vertical stroke 000 right angle and vertical stroke 011 right angle, are found to mix strongly through the color-spin interaction. The physical states can be identified with certain mixtures of the two configurations which diagonalize the hyperfine masses of the color-spin interaction. Matching these states to two scalar resonances a_0(980), a_0(1450) or to K"*_0(800), K"*_0(1430) depending on the isospin channel, we find that their mass splittings are qualitatively consistent with the hyperfine mass splittings, which can support their tetraquark structure. To test our mixing scheme further, we also construct the tetraquarks for J = 1, J = 2 with the spin configurations vertical stroke 111 right angle and vertical stroke 2011 right angle, and we discuss possible candidates in the physical spectrum. (orig.)

Inhibitory effect of the essential oil from Cinnamomum zeylanicum Blume leaves on some food-related bacteria Efeito inibitório do óleo essencial das folhas de Cinnamomum zeylanicum Blume sobre bactérias de interesse em alimentos

Directory of Open Access Journals (Sweden)

Vinicius Nogueira Trajano

2010-09-01

Full Text Available Cinnamomum zeylanicum Blume, Lauraceae, has long been known for having many biological properties. This study aimed to identify the constituents of the essential oil from C. zeylanicum leaves using GC-MS and to assess its inhibitory effect on Salmonella enterica, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa based on MIC and MBC determination and kill-time study. Eugenol (73.27% was the most prevalent compound in the essential oil followed by trans-β-cariophyllene (5.38%, linalool (3.31%, and alcohol cinamic acetate (2.53%. The results showed an interesting antibacterial activity of the oil with MIC ranging from 1.25 to 10 µL.mL-1. MBC values were in the range of 20 - 80 µL.mL-1. A concentration of 10 and 40 µL.mL-1 of the essential oil caused a fast and steady decrease in viable cell count (2 to 5 log cycles of all assayed strains along 24 hours. A concentration of 40 µL.mL-1 of the oil provided a total elimination of the initial inocula of S. aureus after 2 hours. These results show the possibility of regarding the essential oil from C. zeylanicum leaves as alternative sources of antimicrobial compounds to be applied in food conservation systems.Cinnamomum zeylanicum Blume, Lauraceae, é uma espécie vegetal reconhecida, a longo tempo, como possuidora de muitas propriedades biológicas. Este estudo objetivou identificar os constituintes do óleo essencial das folhas de C. zeylanicum, utilizando CG-EM, e avaliar seu efeito inibitório sobre Salmonella enterica, Escherichia coli, Staphylococcus aureus e Pseudomonas aeruginosa através da determinação da CIM e CBM, bem como através da análise do tempo de morte bacteriana. Eugenol (73,27% foi o composto mais prevalente no óleo essencial, seguido por trans-β-cariofileno (5,38%, linalol (3,31% e álcool acetato cinâmico (2,53%. Os resultados mostraram uma interessante atividade antibacteriana do óleo essencial com CIM, variando de 1,25 a 10 µL.mL-1. Os valores de

The Accelerating Spin Of 9P/Tempel 1

Science.gov (United States)

Belton, Michael J.; Drahus, M.

2007-10-01

Deep Impact approach photometry has been analyzed using the dynamical techniques introduced by Drahus and Waniak (2006). Clear indications of acceleration (0.70 +/- 0.24 x 10-7 h-2) in the spin rate are found together with a spin period of 40.850 +/- 0.017 h at the mid point of the data set (June 2.38304, 2005 UT). This measurement of acceleration in the spin is similar to that deduced independently from a combination of spin rate measurements derived from the Deep Impact Earth-based campaign (Meech et al. 2005), Spitzer observations (Lisse et al. 2005), and Deep Impact approach data (A'Hearn et al. 2005). Estimates of the spin rate from these sources (Belton et al. 2007) at epochs between 1999 and 2006 were coupled through the 2005 perihelion passage using a heuristic spin rate change model based on non-gravitational torques due to the outflow of H2O. This model yields a preliminary estimate of 1.15×10-7 h-2 for the acceleration of the spin at the mid point of the data set; it also suggests that the net torque is dominated by activity in the Northern hemisphere of the nucleus. Although non-constant periodicities have been reported for a few comets before, the evidence has never been detected as clearly and unambiguously as for 9P/Tempel 1. This discovery strongly impacts the preparations for the Stardust-NExT mission (http://stardust.jpl.nasa.gov/news/status/070703.html) scheduled to arrive at the comet in 2011. References: A'Hearn, M.F. and 32 colleagues, 2005. Science 310, 258-264. Belton, M.J.S. and 35 colleagues, 2007. In preparation. Drahus, M, and Waniak, W. 2006, Icarus 185, 544 Lisse, C.M and 8 colleagues 2005. Astrophys. J. 625, L139-L142. Meech, K.J. and 208 colleagues, 2005. Science 310, 265-269.

A new analysis of archival images of comet 29P/Schwassmann-Wachmann 1 to constrain the rotation state of and active regions on its nucleus

Science.gov (United States)

Schambeau, C.; Fernández, Y.; Samarasinha, N.; Mueller, B.; Woodney, L.; Lisse, C.; Kelley, M.; Meech, K.

2014-07-01

Introduction: 29P/Schwassmann-Wachmann 1 (SW1) is a unique comet (and Centaur) with an almost circular orbit just outside the orbit of Jupiter. This orbit results in SW1 receiving a nearly constant insolation, thus giving a simpler environment in which to study thermal properties and behaviors of this comet's nucleus. Such knowledge is crucial for improving our understanding of coma morphology, nuclear thermal evolution, and nuclear structure. To this end, our overarching goal is to develop a thermophysical model of SW1's nucleus that makes use of realistic physical and structural properties as inputs. This model will help to explain the highly variable gas- and dust-production rates of this comet; SW1 is well known for its frequent but stochastic outbursts of mass loss [1,2,3]. Here we will report new constraints on the effective radius, beaming parameter, spin state, and location of active regions on the nucleus of SW1. Results: The analysis completed so far consists of a re-analysis of Spitzer Space Telescope thermal-IR images of SW1 from UT 2003 November 21 and 24, when SW1 was observed outside of outburst. The images are from Spitzer's IRAC 5.8-μm and 8.0-μm bands and MIPS 24.0-μm and 70-μm bands. This analysis is similar to that of Stansberry et al. [4, 5], but with data products generated from the latest Spitzer pipeline. Also, analysis of the 5.8-μm image had not been reported before. Coma removal techniques (e.g., Fernández et al. [6]) were applied to each image letting us measure the nuclear point-source contribution to each image. The measured flux densities for each band were fit with a Near Earth Asteroid Thermal Model (NEATM, [7]) and resulted in values for the effective radius of SW1's nucleus, constraints on the thermal inertia, and an IR beaming-parameter value. Current efforts have shifted to constraining the spin properties of SW1's nucleus and surface areas of activity through use of an existing Monte Carlo model [8, 9] to reproduce

Spin glass transition in the rhombohedral LiNi1/3Mn1/3Co1/3O2

International Nuclear Information System (INIS)

Bie, Xiaofei; Yang, Xu; Han, Bing; Chen, Nan; Liu, Lina; Wei, Yingjin; Wang, Chunzhong; Chen, Hong; Du, Fei; Chen, Gang

2013-01-01

Highlights: •The Rietveld analysis of XRD data reveals a single phase with rhombohedral structure. •Dc susceptibility data suggest a spin glass behavior at low T in the 333 compound. •The ac susceptibility measurements have been observed in the typical SG system. •Three models have been employed to study the behavior of the spin glass state. •Both geometrical frustration and disorder play important role in the formation of SG. -- Abstract: Layered LiNi 1/3 Mn 1/3 Co 1/3 O 2 has been synthesized by co-precipitation method, and the magnetic properties were comprehensively studied by dc and ac susceptibilities. The dc magnetization curves show the irreversibility and spin freezing behavior at 109 K and 9 K. The evolution of real and imaginary part of ac susceptibility under different frequencies indicates a spin glass transition at low temperature. Three models (the Néel–Arrhenius law, the Vogel–Fulcher law, and the power law) have been employed to study the relaxation behavior of the spin glass state. Both frustration and disorder play important role in the formation of spin glass

Spin structure factors of Heisenberg spin chain in the presence of anisotropy and magnetic field

Energy Technology Data Exchange (ETDEWEB)

Rezania, H., E-mail: rezania.hamed@gmail.com

2017-02-01

We have theoretically studied the spin structure factors of spin chain in the presence of longitudinal field and transverse anisotropy. The possible effects of easy axis magnetization are investigated in terms of anisotropy in the Heisenberg interactions. This anisotropy is considered for exchange coupling constants perpendicular to magnetic field direction. The original spin model hamiltonian is mapped to a bosonic model via a hard core bosonic transformation where an infinite hard core repulsion is imposed to constrain one boson occupation per site. Using Green's function approach, the energy spectrum of quasiparticle excitation has been obtained. The spectrum of the bosonic gas has been implemented in order to obtain two particle propagator which corresponds to spin structure factor of original Heisenberg chain model Hamiltonian. The results show the position of peak in the longitudinal structure factor at fixed value for anisotropy moves to higher frequency with magnetic field. Also the intensity of dynamical structure factor decreases with magnetic field. A small dependence of longitudinal dynamical spin structure factor on the anisotropy is observed for fixed value of magnetic field. Our results show longitudinal static structure factor is found to be monotonically increasing with magnetic field due to increase of spins aligning along magnetic field. Furthermore the dispersion behaviors of static longitudinal and transverse structure factors for different magnetic fields and anisotropy parameters are addressed. - Highlights: • Theoretical calculation of spin structure factors of Heisenberg chain. • The investigation of the effect of anisotropy spin structure factors of Heisenberg chain. • The investigation of the effect of magnetic field on spin structure factors of Heisenberg chain.

Spin structure factors of Heisenberg spin chain in the presence of anisotropy and magnetic field

International Nuclear Information System (INIS)

Rezania, H.

2017-01-01

We have theoretically studied the spin structure factors of spin chain in the presence of longitudinal field and transverse anisotropy. The possible effects of easy axis magnetization are investigated in terms of anisotropy in the Heisenberg interactions. This anisotropy is considered for exchange coupling constants perpendicular to magnetic field direction. The original spin model hamiltonian is mapped to a bosonic model via a hard core bosonic transformation where an infinite hard core repulsion is imposed to constrain one boson occupation per site. Using Green's function approach, the energy spectrum of quasiparticle excitation has been obtained. The spectrum of the bosonic gas has been implemented in order to obtain two particle propagator which corresponds to spin structure factor of original Heisenberg chain model Hamiltonian. The results show the position of peak in the longitudinal structure factor at fixed value for anisotropy moves to higher frequency with magnetic field. Also the intensity of dynamical structure factor decreases with magnetic field. A small dependence of longitudinal dynamical spin structure factor on the anisotropy is observed for fixed value of magnetic field. Our results show longitudinal static structure factor is found to be monotonically increasing with magnetic field due to increase of spins aligning along magnetic field. Furthermore the dispersion behaviors of static longitudinal and transverse structure factors for different magnetic fields and anisotropy parameters are addressed. - Highlights: • Theoretical calculation of spin structure factors of Heisenberg chain. • The investigation of the effect of anisotropy spin structure factors of Heisenberg chain. • The investigation of the effect of magnetic field on spin structure factors of Heisenberg chain.

Continuous spin fields of mixed-symmetry type

Science.gov (United States)

Alkalaev, Konstantin; Grigoriev, Maxim

2018-03-01

We propose a description of continuous spin massless fields of mixed-symmetry type in Minkowski space at the level of equations of motion. It is based on the appropriately modified version of the constrained system originally used to describe massless bosonic fields of mixed-symmetry type. The description is shown to produce generalized versions of triplet, metric-like, and light-cone formulations. In particular, for scalar continuous spin fields we reproduce the Bekaert-Mourad formulation and the Schuster-Toro formulation. Because a continuous spin system inevitably involves infinite number of fields, specification of the allowed class of field configurations becomes a part of its definition. We show that the naive choice leads to an empty system and propose a suitable class resulting in the correct degrees of freedom. We also demonstrate that the gauge symmetries present in the formulation are all Stueckelberg-like so that the continuous spin system is not a genuine gauge theory.

Interplay between the Dzyaloshinskii-Moriya term and external fields on spin transport in the spin-1/2 one-dimensional antiferromagnet

Science.gov (United States)

Lima, L. S.

2018-05-01

We study the effect of the uniform Dzyaloshinskii-Moriya interaction (symmetric exchange anisotropy) and arbitrary oriented external magnetic fields on spin conductivity in the spin-1/2 one-dimensional Heisenberg antiferromagnet. The spin conductivity is calculated employing abelian bosonization and the Kubo formalism of transport. We investigate the influence of three competing phases at zero-temperature, (Néel phase, dimerized phase and gapless Luttinger liquid phase) on the AC spin conductivity.

Constraining new resonant physics with top spin polarisation information

Energy Technology Data Exchange (ETDEWEB)

Englert, Christoph; Nordstroem, Karl [University of Glasgow, SUPA, School of Physics and Astronomy, Glasgow (United Kingdom); Ferrando, James [DESY Hamburg, Hamburg (Germany)

2017-06-15

We provide a comprehensive analysis of the power of including top quark-polarisation information to kinematically challenging top pair resonance searches, for which ATLAS and CMS start losing sensitivity. Following the general modelling and analysis strategies pursued by the experiments, we analyse the semi-leptonic and the di-lepton channels and show that including polarisation information can lead to large improvements in the limit setting procedures with large data sets. This will allow us to set stronger limits for parameter choices where sensitivity from the invariant mass of the top pair is not sufficient. This highlights the importance of spin observables as part of a more comprehensive set of observables to gain sensitivity to BSM resonance searches. (orig.)

The Ginibre inequality

International Nuclear Information System (INIS)

Sylvester, G.S.

1980-01-01

In the Ising-type models of statistical mechanics and the related quantum field theories, an inequality of Ginibre implies useful positivity and monotonicity properties: the Griffiths correlation inequalities. Essentially, the Ginibre inequality states that certain functions on the cycle group of a graph are positive definite. This has been proved for arbitrary graphs when the spin dimensions is 1 or 2 (classical Ising or plane rotator models). We give a counterexample to show that these spin dimensions are the only ones for which the Ginibre inequality is generally true: there are graphs for which it never holds when the spin dimension is at least 3. On the other hand, we show that for any graph the inequality holds for the apparent leading term in the large-spin-dimension limit. (The leading term vanishes in the graph of the counterexample.) Based on these results, one expects the Ginibre inequality to be true in most instances, with infrequent exceptions. A numerical survey supports this. The surprising failure of the Ginibre inequality in higher dimensions need not necessarily mean the Griffiths inequalities fail as well, but a different approach to them is required. (orig.)

THE MOST MASSIVE ACTIVE BLACK HOLES AT z ∼ 1.5-3.5 HAVE HIGH SPINS AND RADIATIVE EFFICIENCIES

International Nuclear Information System (INIS)

Trakhtenbrot, Benny

2014-01-01

The radiative efficiencies (η) of 72 luminous unobscured active galactic nuclei at z ∼ 1.5-3.5, powered by some of the most massive black holes (BHs), are constrained. The analysis is based on accretion disk (AD) models, which link the continuum luminosity at rest-frame optical wavelengths and the BH mass (M BH ) to the accretion rate through the AD, M-dot AD . The data are gathered from several literature samples with detailed measurements of the Hβ emission line complex, observed at near-infrared bands. When coupled with standard estimates of bolometric luminosities (L bol ), the analysis suggests high radiative efficiencies, with most of the sources showing η > 0.2, that is, higher than the commonly assumed value of 0.1, and the expected value for non-spinning BHs (η = 0.057). Even under more conservative assumptions regarding L bol (i.e., L bol = 3 × L 5100 ), most of the extremely massive BHs in the sample (i.e., M BH ≳ 3 × 10 9 M ☉ ) show radiative efficiencies which correspond to very high BH spins (a * ), with typical values well above a * ≅ 0.7. These results stand in contrast to the predictions of a ''spin-down'' scenario, in which a series of randomly oriented accretion episodes leads to a * ∼ 0. Instead, the analysis presented here strongly supports a ''spin-up'' scenario, which is driven by either prolonged accretion or a series of anisotropically oriented accretion episodes. Considering the fact that these extreme BHs require long-duration or continuous accretion to account for their high masses, it is argued that the most probable scenario for the super-massive black holes under study is that of an almost continuous sequence of randomly yet not isotropically oriented accretion episodes

Report of 3 Cases of Emery-Dreifuss Muscular Dystrophy in a Family

Directory of Open Access Journals (Sweden)

P. Yazdanpanah

2004-01-01

Full Text Available Emery-Dreifuss muscular dystrophy (EDMDcan be seen in the middle childhood and the genetic patterns of them are X-linked recessive, autosomal dominant or recessive. The classic triad of this disease are: 1-early contractures, particularly of the elbows, achilles tendons, and posterior cervical muscles; 2-cardiac conduction defects ;and 3- a slowly progressive weakness and atrophy in a humeroperoneal distribution. The early onset of contractures before the onset of any significant weakness is unique to this disease. This case study was done in two 12 and 3.5 years old brothers and their 8 years old sister in a family. The first one referred to the medical center because of his weakness muscles of shoulders and arms. The second case was referred with tip toe walking which has been started 8 months ago. The third case was referred with difficulties in walking and sitting and surgery on achilles tendons for her and the first case was performed at 4 and 8 years ago respectively. In physical examination contractures of achilles tendons , weakness of pelvic girdle muscles, positive gowers sign and tip toe walking were observed in all three cases . Echocardiogram in both boys and CK enzyme in all 3 patients were normal. In ECGs atrial flutter with 3:1 AV block was seen in all 3 individuals. Muscle biopsy was nonspecific in the first case and mild focal atrophy was seen in the second case. Findings of myopathic patterns in electromyography were seen in all 3 patients. The genetic pattern of EDMD in this family is autosomal dominant. Stretching exercises and modalities such as ultrasound and hot pack were applied for these cases. The second was not responded and surgery of achilles tendons release was recommended for him.

Measuring the spin of black holes in binary systems using gravitational waves.

Science.gov (United States)

Vitale, Salvatore; Lynch, Ryan; Veitch, John; Raymond, Vivien; Sturani, Riccardo

2014-06-27

Compact binary coalescences are the most promising sources of gravitational waves (GWs) for ground-based detectors. Binary systems containing one or two spinning black holes are particularly interesting due to spin-orbit (and eventual spin-spin) interactions and the opportunity of measuring spins directly through GW observations. In this Letter, we analyze simulated signals emitted by spinning binaries with several values of masses, spins, orientations, and signal-to-noise ratios, as detected by an advanced LIGO-Virgo network. We find that for moderate or high signal-to-noise ratio the spin magnitudes can be estimated with errors of a few percent (5%-30%) for neutron star-black hole (black hole-black hole) systems. Spins' tilt angle can be estimated with errors of 0.04 rad in the best cases, but typical values will be above 0.1 rad. Errors will be larger for signals barely above the threshold for detection. The difference in the azimuth angles of the spins, which may be used to check if spins are locked into resonant configurations, cannot be constrained. We observe that the best performances are obtained when the line of sight is perpendicular to the system's total angular momentum and that a sudden change of behavior occurs when a system is observed from angles such that the plane of the orbit can be seen both from above and below during the time the signal is in band. This study suggests that direct measurement of black hole spin by means of GWs can be as precise as what can be obtained from x-ray binaries.

Terrestrial Sagnac delay constraining modified gravity models

Science.gov (United States)

Karimov, R. Kh.; Izmailov, R. N.; Potapov, A. A.; Nandi, K. K.

2018-04-01

Modified gravity theories include f(R)-gravity models that are usually constrained by the cosmological evolutionary scenario. However, it has been recently shown that they can also be constrained by the signatures of accretion disk around constant Ricci curvature Kerr-f(R0) stellar sized black holes. Our aim here is to use another experimental fact, viz., the terrestrial Sagnac delay to constrain the parameters of specific f(R)-gravity prescriptions. We shall assume that a Kerr-f(R0) solution asymptotically describes Earth's weak gravity near its surface. In this spacetime, we shall study oppositely directed light beams from source/observer moving on non-geodesic and geodesic circular trajectories and calculate the time gap, when the beams re-unite. We obtain the exact time gap called Sagnac delay in both cases and expand it to show how the flat space value is corrected by the Ricci curvature, the mass and the spin of the gravitating source. Under the assumption that the magnitude of corrections are of the order of residual uncertainties in the delay measurement, we derive the allowed intervals for Ricci curvature. We conclude that the terrestrial Sagnac delay can be used to constrain the parameters of specific f(R) prescriptions. Despite using the weak field gravity near Earth's surface, it turns out that the model parameter ranges still remain the same as those obtained from the strong field accretion disk phenomenon.

A many-body analysis of NMR in spin-1/2 system

International Nuclear Information System (INIS)

Roy, G.K.; Sinha, S.K.

1977-01-01

The NMR absorption in a spin-1/2 system at finite temperature has been analysed by using the linear response theory and calculating the finite-temperature retarted spin Green's function. In this calculations, the Drone-Fermion representation for the spin operators has been used. A model spin-lattice interaction which is linear in phonon and Fermion operators has been considered, and its effect on a mutually non-interacting spin system has been calculated using the diagrammatic expansions technique. It is found that the complete summing up of a particular class of diagrams yields the Lorentzian shape of the resonance line. (author)

Spin Torques in Systems with Spin Filtering and Spin Orbit Interaction

KAUST Repository

Ortiz Pauyac, Christian

2016-06-19

In the present thesis we introduce the reader to the field of spintronics and explore new phenomena, such as spin transfer torques, spin filtering, and three types of spin-orbit torques, Rashba, spin Hall, and spin swapping, which have emerged very recently and are promising candidates for a new generation of memory devices in computer technology. A general overview of these phenomena is presented in Chap. 1. In Chap. 2 we study spin transfer torques in tunnel junctions in the presence of spin filtering. In Chap. 3 we discuss the Rashba torque in ferromagnetic films, and in Chap. 4 we study spin Hall effect and spin swapping in ferromagnetic films, exploring the nature of spin-orbit torques based on these mechanisms. Conclusions and perspectives are summarized in Chap. 5.

Exactly solvable spin-1 Ising–Heisenberg diamond chain with the second-neighbor interaction between nodal spins

International Nuclear Information System (INIS)

Hovhannisyan, V V; Ananikian, N S; Strečka, J

2016-01-01

The spin-1 Ising–Heisenberg diamond chain with the second-neighbor interaction between nodal spins is rigorously solved using the transfer-matrix method. In particular, exact results for the ground state, magnetization process and specific heat are presented and discussed. It is shown that further-neighbor interaction between nodal spins gives rise to three novel ground states with a translationally broken symmetry, but at the same time, does not increases the total number of intermediate plateaus in a zero-temperature magnetization curve compared with the simplified model without this interaction term. The zero-field specific heat displays interesting thermal dependencies with a single- or double-peak structure. (paper)

Consistent equations for interacting gauge fields of all spins in 3+1 dimensions

Energy Technology Data Exchange (ETDEWEB)

Vasiliev, M A [AN SSSR, Moscow. Inst. Teoreticheskoj Fiziki (USSR)

1990-07-05

Consistent equations of motion of interacting gauge fields of all spins in 3+1 dimensions are formulated in a closed form. These equations are explicitly general coordinate invariant, possess all necessary higher spin gauge symmetries and reduce to the usual equations of free massless fields of all spins s=0, 1/2, 1, ..., {infinity} at the linearized level. In the spin-2 sector, the proposed equations are equivalent to the Einstein equations with the cosmological term. (orig.).

Fracton topological order from nearest-neighbor two-spin interactions and dualities

Science.gov (United States)

Slagle, Kevin; Kim, Yong Baek

2017-10-01

Fracton topological order describes a remarkable phase of matter, which can be characterized by fracton excitations with constrained dynamics and a ground-state degeneracy that increases exponentially with the length of the system on a three-dimensional torus. However, previous models exhibiting this order require many-spin interactions, which may be very difficult to realize in a real material or cold atom system. In this work, we present a more physically realistic model which has the so-called X-cube fracton topological order [Vijay, Haah, and Fu, Phys. Rev. B 94, 235157 (2016), 10.1103/PhysRevB.94.235157] but only requires nearest-neighbor two-spin interactions. The model lives on a three-dimensional honeycomb-based lattice with one to two spin-1/2 degrees of freedom on each site and a unit cell of six sites. The model is constructed from two orthogonal stacks of Z2 topologically ordered Kitaev honeycomb layers [Kitaev, Ann. Phys. 321, 2 (2006), 10.1016/j.aop.2005.10.005], which are coupled together by a two-spin interaction. It is also shown that a four-spin interaction can be included to instead stabilize 3+1D Z2 topological order. We also find dual descriptions of four quantum phase transitions in our model, all of which appear to be discontinuous first-order transitions.

SU(2) x U(1) unified theory for charge, orbit and spin currents

International Nuclear Information System (INIS)

Jin Peiqing; Li Youquan; Zhang Fuchun

2006-01-01

Spin and charge currents in systems with Rashba or Dresselhaus spin-orbit couplings are formulated in a unified version of four-dimensional SU(2) x U(1) gauge theory, with U(1) being the Maxwell field and SU(2) being the Yang-Mills field. While the bare spin current is non-conserved, it is compensated by a contribution from the SU(2) gauge field, which gives rise to a spin torque in the spin transport, consistent with the semi-classical theory of Culcer et al. Orbit current is shown to be non-conserved in the presence of electromagnetic fields. Similar to the Maxwell field inducing forces on charge and charge current, we derive forces acting on spin and spin current induced by the Yang-Mills fields such as the Rashba and Dresselhaus fields and the sheer strain field. The spin density and spin current may be considered as a source generating Yang-Mills field in certain condensed matter systems

The spin dependent structure function g1 of the deuteron and the proton

International Nuclear Information System (INIS)

Klostermann, L.

1995-01-01

This thesis presents a study on the spin structure of the nucleon, via deep inelastic scattering (DIS) of polarised nuons on polarised proton and deuterium targets. The work was done in the Spin Muon Collaboration (SMC) at CERN in Geneva. From the asymmetry in the scattering cross section for nucleon and lepton spins parallel and anti-parallel, one con determine the spin dependent structure function g 1 , which contains information on the quark and gluon spin distribution functions. The interpretation in the frame work of the quark parton model (QPM) of earlier results on g 1 p by the European Muon Collaboration (EMC), gave an indication that only a small fraction of the proton spin, compatible with zero, is carried by the spins of the constituent quarks. The SMC was set up to check this unexpected result with improved accuracy, and to combine measurements of g 1 p and g 1 d to test a fundamental sum rule in quantum chromodynamics (QCD), the Bjorken sum rule. (orig./WL)

Drones, quasi-spin or iso-spin. A comparison of many-body techniques for general spin

International Nuclear Information System (INIS)

McKenzie, B.J.; Stedman, G.E.

1976-01-01

For an effective-spin system with 2S + 1 levels there are a number of possible mappings of spin onto pseudo-fermion operators. The relative merits of three of these methods are investigated by calculating to second order the dispersion relation for coupled spin-phonon modes in crystals containing S = 1 effective spin impurities. It is found that the drone formalism quickly becomes intractable at higher spin values, as does the related quasi-spin formalism developed in contrast with the iso-spin (or Abrinkosov projection) formalism. (author)

TU-EF-BRA-02: Longitudinal Proton Spin Relaxation and T1-Imaging

International Nuclear Information System (INIS)

Lemen, L.

2015-01-01

NMR, and Proton Density MRI of the 1D Patient - Anthony Wolbarst Net Voxel Magnetization, m(x,t). T1-MRI; The MRI Device - Lisa Lemen ‘Classical’ NMR; FID Imaging in 1D via k-Space - Nathan Yanasak Spin-Echo; S-E/Spin Warp in a 2D Slice - Ronald Price Magnetic resonance imaging not only reveals the structural, anatomic details of the body, as does CT, but also it can provide information on the physiological status and pathologies of its tissues, like nuclear medicine. It can display high-quality slice and 3D images of organs and vessels viewed from any perspective, with resolution better than 1 mm. MRI is perhaps most extraordinary and notable for the plethora of ways in which it can create unique forms of image contrast, reflective of fundamentally different biophysical phenomena. As with ultrasound, there is no risk from ionizing radiation to the patient or staff, since no X-rays or radioactive nuclei are involved. Instead, MRI harnesses magnetic fields and radio waves to probe the stable nuclei of the ordinary hydrogen atoms (isolated protons) occurring in water and lipid molecules within and around cells. MRI consists, in essence, of creating spatial maps of the electromagnetic environments around these hydrogen nuclei. Spatial variations in the proton milieus can be related to clinical differences in the biochemical and physiological properties and conditions of the associated tissues. Imaging of proton density (PD), and of the tissue proton spin relaxation times known as T1 and T2, all can reveal important clinical information, but they do so with approaches so dissimilar from one another that each is chosen for only certain clinical situations. T1 and T2 in a voxel are determined by different aspects of the rotations and other motions of the water and lipid molecules involved, as constrained by the local biophysical surroundings within and between its cells – and they, in turn, depend on the type of tissue and its state of health. Three other common

TU-EF-BRA-02: Longitudinal Proton Spin Relaxation and T1-Imaging

Energy Technology Data Exchange (ETDEWEB)

Lemen, L. [Univ Cincinnati (United States)

2015-06-15

NMR, and Proton Density MRI of the 1D Patient - Anthony Wolbarst Net Voxel Magnetization, m(x,t). T1-MRI; The MRI Device - Lisa Lemen ‘Classical’ NMR; FID Imaging in 1D via k-Space - Nathan Yanasak Spin-Echo; S-E/Spin Warp in a 2D Slice - Ronald Price Magnetic resonance imaging not only reveals the structural, anatomic details of the body, as does CT, but also it can provide information on the physiological status and pathologies of its tissues, like nuclear medicine. It can display high-quality slice and 3D images of organs and vessels viewed from any perspective, with resolution better than 1 mm. MRI is perhaps most extraordinary and notable for the plethora of ways in which it can create unique forms of image contrast, reflective of fundamentally different biophysical phenomena. As with ultrasound, there is no risk from ionizing radiation to the patient or staff, since no X-rays or radioactive nuclei are involved. Instead, MRI harnesses magnetic fields and radio waves to probe the stable nuclei of the ordinary hydrogen atoms (isolated protons) occurring in water and lipid molecules within and around cells. MRI consists, in essence, of creating spatial maps of the electromagnetic environments around these hydrogen nuclei. Spatial variations in the proton milieus can be related to clinical differences in the biochemical and physiological properties and conditions of the associated tissues. Imaging of proton density (PD), and of the tissue proton spin relaxation times known as T1 and T2, all can reveal important clinical information, but they do so with approaches so dissimilar from one another that each is chosen for only certain clinical situations. T1 and T2 in a voxel are determined by different aspects of the rotations and other motions of the water and lipid molecules involved, as constrained by the local biophysical surroundings within and between its cells – and they, in turn, depend on the type of tissue and its state of health. Three other common

Caracterización de suelos bajo bosques de Nothofagus betuloides (Mirb Blume, en Tierra del Fuego, Chile Characterization of soils of Nothofagus betuloides (Mirb Blume forests, in Tierra del Fuego, Chile

Directory of Open Access Journals (Sweden)

VÍCTOR GERDING

2002-12-01

Full Text Available En tres sectores de la parte occidental de Tierra del Fuego (54º45'-54º15' S, 68º40'-70º10' O se caracterizó morfológica, física y químicamente los suelos bajo bosques de coigüe de Magallanes (Nothofagus betuloides (Mirb Blume y sus especies asociadas lenga (Nothofagus pumilio (P. et E. Krasser y canelo (Drimys winteri Forst.. Se describieron 85 perfiles de suelo y aproximadamente 250 observaciones con bastón pedológico. Los suelos bajo coigüe de Magallanes eran jóvenes, muy influidos por la actividad volcánica, topografía y clima. Se observó la presencia de los órdenes Spodosol e Iceptisol, principalmente. En general los suelos eran delgados a muy delgados (mayoritariamente entre 10 y 40 cm, con un alto volumen de esqueleto, textura franca, estructura masiva a granular, capacidad de agua aprovechable baja y drenaje externo e interno moderado a lento. Además, presentan una alta acidez (pH 4-5,5, una baja oferta nutricional y muy altos niveles de saturación de aluminio (promedio > 60 %. El mantillo (Oe/Oa presentó condiciones adecuadas para el desarrollo radicular. Existe comúnmente un horizonte blanco (frecuentemente 10 YR 5/1-2 inmediatamente debajo del mantillo, con textura franco limosa y estructura masiva, con arraigamiento muy bajo. Se plantea como hipótesis que este horizonte se originó por depósitos de cenizas volcánicas y procesos de podzolización. Se concluye que la fertilidad de estos suelos es baja debido a limitantes físicas (dificultades de arraigamiento y químicas (acidez, toxicidad de aluminio, baja oferta de basesSoils under coigüe de Magallanes (Nothofagus betuloides (Mirb Blume forests, located in the oriental part of Tierra del Fuego (54º45'-54º15' S, 68º40'-70º10' W, were characterized morphologically, physically and chemically. Associated tree species were lenga (Nothofagus pumilio (P. et E. Krasser and canelo (Drimys winterii Forst.. A total of 85 soil profiles and approximately 250 soil

Magnetization and ESR studies of La{sub 0.67}(Ca{sub 1−x}Mg{sub x}){sub 0.33}MnO{sub 3} systems

Energy Technology Data Exchange (ETDEWEB)

Sendil Kumar, A., E-mail: sendilphy@gmail.com [School of Physics, University of Hyderabad, Hyderabad, Telangana, 500 046 (India); Ravinder Reddy, K [School of Engineering Sciences & Technology, University of Hyderabad, Hyderabad, Telangana, 500 046 (India); Bhatnagar, Anil K. [School of Physics, University of Hyderabad, Hyderabad, Telangana, 500 046 (India); School of Engineering Sciences & Technology, University of Hyderabad, Hyderabad, Telangana, 500 046 (India)

2015-08-05

Highlights: • Mg substitution reduces the ferromagnetic strength. • Inhomogeneous broadening is due to phase separation. • Griffiths phase existence is probed. - Abstract: Magnetization studies and line shape analysis on Electron Spin Resonance (ESR) spectra of La{sub 0.67}(Ca{sub 1−x}Mg{sub x}){sub 0.33}MnO{sub 3} are carried out. In paramagnetic phase well above T{sub c}, the ESR spectra are single Lorentzian but below and near T{sup ∗}{sub ΔHPP}, (T{sup ∗}{sub ΔHPP} is temperature at which line width is minimum) inhomogeneous broadening with asymmetry in the signal is observed due to phase separation. The resonance field below T{sup ∗}{sub ΔHPP} decreases with decreasing temperature. Above T{sub c} the intensity of the ESR spectra obeys the thermally activated model (Arrhenius behavior). Substitution of Mg weakens the ferromagnetic interaction and evolution of change in lineshape near T{sub c} is an evidence of Griffiths phase (coexistence of paramagnetic and ferromagnetic) in Mg doped LCMO system.

Magnetoresistance in spin glass alloys: Theory and experiment

International Nuclear Information System (INIS)

Mookerjee, A.; Chowdhury, D.

1984-11-01

The magnetoresistance of spin glass alloys is examined within the percolation model of Mookerjee and Chowdhury (1983), the mode freezing model of Hertz (1983) and the constrained relaxation model of Palmer et al. (1984). All three models yield qualitatively similar results in excellent agreement with the experiments of Majumdar (1983, 1984) on AgMn. (author)

Higher-spin cluster algorithms: the Heisenberg spin and U(1) quantum link models

Energy Technology Data Exchange (ETDEWEB)

Chudnovsky, V

2000-03-01

I discuss here how the highly-efficient spin-1/2 cluster algorithm for the Heisenberg antiferromagnet may be extended to higher-dimensional representations; some numerical results are provided. The same extensions can be used for the U(1) flux cluster algorithm, but have not yielded signals of the desired Coulomb phase of the system.

Higher-spin cluster algorithms: the Heisenberg spin and U(1) quantum link models

International Nuclear Information System (INIS)

Chudnovsky, V.

2000-01-01

I discuss here how the highly-efficient spin-1/2 cluster algorithm for the Heisenberg antiferromagnet may be extended to higher-dimensional representations; some numerical results are provided. The same extensions can be used for the U(1) flux cluster algorithm, but have not yielded signals of the desired Coulomb phase of the system

Spin wave energy dispersion in KCuF/sub 3/: a nearly one-dimensional spin-1/2 antiferromagnet. [4. 7/sup 0/K

Energy Technology Data Exchange (ETDEWEB)

Hutchings, M T; Ikeda, H; Milne, J M

1979-09-28

Using inelastic neutron scattering techniques, the spin wave energy dispersion in the (010) plane of the distorted perovskite KCuF/sub 3/, which exhibits many magnetic properties of the spin-1/2 one-dimensional antiferromagnet, has been investigated at 4.7 K (T/sub N/ = 39 K). The measurements confirm the very strong exchange interaction between the spins in the (001) direction, and show that in this direction the expression for the excitation energies of the spin-1/2 antiferromagnetic chain given by J des Cloizeaux and J J Pearson is obeyed. The exchange interaction between these chains is found to be only 1.6% of that within the chains.

Quantum SU(2|1) supersymmetric Calogero-Moser spinning systems

Science.gov (United States)

Fedoruk, Sergey; Ivanov, Evgeny; Lechtenfeld, Olaf; Sidorov, Stepan

2018-04-01

SU(2|1) supersymmetric multi-particle quantum mechanics with additional semi-dynamical spin degrees of freedom is considered. In particular, we provide an N=4 supersymmetrization of the quantum U(2) spin Calogero-Moser model, with an intrinsic mass parameter coming from the centrally-extended superalgebra \\widehat{su}(2\\Big|1) . The full system admits an SU(2|1) covariant separation into the center-of-mass sector and the quotient. We derive explicit expressions for the classical and quantum SU(2|1) generators in both sectors as well as for the total system, and we determine the relevant energy spectra, degeneracies, and the sets of physical states.

Nuclear spin relaxation in a spin-1/2 antiferromagnetic Heisenberg chain at high fields

International Nuclear Information System (INIS)

Lyo, S.K.

1981-01-01

The proton spin relaxation rate is calculated in the one-dimensional spin-1/2 Heisenberg antiferromagnet α-bis (N-methylsalicylaldiminato)-copper (II), α-CuNSal by using a fermion representation for magnons above the critical field where the magnon spectrum develops a gap. The one-magnon process which is dominant below the critical field is shown to be absent in the presence of a gap in contrast to a previous theory. Instead, we find that the three-magnon rate is large enough to explain the data at low fields. The two-magnon off-resonance damping which enters the expression for the three-magnon rate is calculated by solving the two-magnon scattering exactly, leading to a much smaller value of the rate than that predicted by the Born approximation. Also, in an unsuccessful attempt to resolve the discrepancy between the recently calculated two-magnon rate (dominant at high fields) and the data of α-CuNSal reported by Azevedo et al., we carry out the vertex correction for the spin-density correlation function by summing the RPA series as well as the exchange ladders for the polarization part. We find that, although the exchange enhancement is significantly large, it is nearly canceled out by the RPA correction, and the net effect of the vertex correction is small. This result agrees with the recent data of the similar spin-1/2 antiferromagnetic Heisenberg chain system CuSO 4 x5H 2 O reported by Groen et al. On the other hand, it disagrees with a recent calculation of the two-magnon rate based on a boson representation of spins. To resolve this discrepancy we examine the effect of the boson self-energy correction on the two-magnon rate. The boson spectral shift is found to be quite large in the region where the cited two-boson rate deviates from the two-fermion rate. As a result the two-boson rate is significantly reduced, leading to reasonable agreement with the two-fermion rate

Characterization of nephelium mutabile blume-like structure of carbon nanotubes prepared from palm oil by CVD method

Science.gov (United States)

Maryam, M.; Shamsudin, M. S.; Rusop, M.

2017-09-01

A new structure of carbon nanotube was produced from the Single furnace Aerosol-assisted Catalytic CVD (SFAACVD) method using Palm Oil (PO) as the precursor and Ferrocene (Fe) as the catalyst. A nephelium mutabile blume (rambutan)-like structure of CNTs was found from the black substance collected from the Alumina boat substrate placed inside the furnace. Temperature of furnace which was heated at 600 °C - 800 °C plays an important role in determining the formation of structure. The formation rambutan-like structure of CNTs was optimized at 700 °C and the samples collected were characterized by Field Emission Scanning Electron Microscope (FE-SEM) to obtain the surface morphologies. Raman Spectroscopy (RS) and Thermogravimetric Analysis (TGA) were then used to further study the Raman Spectra and purity of samples.

Numerical study of the spin-1 Ashkin-Teller model

International Nuclear Information System (INIS)

Bekhechi, S.; Badehdah, M.; Benyoussef, A.; Ettaki, B.

1998-07-01

Two non perturbative methods by means of the Transfer-Matrix Finite-Size-Scaling (TMFSS) and Monte Carlo (MC) simulations are used to investigate the spin-1 Ashkin-Teller model (A.T.M.). We have obtained rich phase diagrams with first and second order phase transitions with several multicritical points of higher order. Also this model exhibits a new partially ordered phase PO2 which does not exist in the spin-1/2 Ashkin-Teller model (A.T.M.). Finally, the critical behaviour of this model is discussed. (author)

Anomalous behaviour of the magnetic susceptibility of the mixed spin-1 and spin- 1/2 anisotropic Heisenberg model in the Oguchi approximation

International Nuclear Information System (INIS)

Bobak, Andrej; Dely, Jan; Pokorny, Vladislav

2010-01-01

The effects of both an exchange anisotropy and a single-ion anisotropy on the magnetic susceptibility of the mixed spin-1 and spin- 1/2 Heisenberg model are investigated by the use of an Oguchi approximation. Particular emphasis is given to the simple cubic lattice with coordination number z = 6 for which the magnetic susceptibility is determined numerically. Anomalous behaviour in the thermal variation of the magnetic susceptibility in the low-temperature region is found due to the applied negative single-ion anisotropy field strength. Also, the difference between the behaviours of the magnetic susceptibility of the Heisenberg and Ising models is discussed.

The susceptibilities in the spin-S Ising model

International Nuclear Information System (INIS)

Ainane, A.; Saber, M.

1995-08-01

The susceptibilities of the spin-S Ising model are evaluated using the effective field theory introduced by Tucker et al. for studying general spin-S Ising model. The susceptibilities are studied for all spin values from S = 1/2 to S = 5/2. (author). 12 refs, 4 figs

Induksi Poliploidi Phalaenopsis amabilis (L. Blume dan Phalaenopsis amboinensis J. J. Smith dengan Kolkisin dalam Kultur In Vitro

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Eka Martha Della Rahayu

2016-02-01

Full Text Available ABSTRACTPhalaenopsis amabilis (L. Blume and Phalaenopsis amboinensis J.J. Smith (diploid are important in Phalaenopsis breeding. Polyploid species are needed for crossing with polyploid hybrid varities of Phalaenopsis. The objectives of this study were to obtain effective concentration of colchicine to induce polyploidy and to produce polyploid plantlets of P. amabilis and P. amboinensis. Experiment was arranged in randomized complete block design with one factor, the colchicine concentration. Protocorms of P. amabilis and P. amboinensis were immersed in half strength of Murashige-Skoog (1/2 MS liquid media added with colchicine (0; 0.5; 5; 25; 50, and 75 mg L-1 for 10 days. The results showed that higher concentration of colchicine on both species did not have significant effect on the survival of the plantlets at 24 weeks after treatment. The average number of leaves and roots of colchicine treated planlets from both species were less than the control plantlets. Immersing protocorm in colchicine at concentration of 50 mg L-1 for 10 days was effective in inducing polyploid plantlets of P. amabilis and P. amboinensis with the frequency of 33.3% and 40%, respectively. Polyploid plantlet has larger stomata size and lower stomata density than the diploid ones.Keywords: chromosome number, colchicine, polyploid, protocorm, stomatal density, stomatal size

Penggunaan Citra Satelit untuk Mengetahui Persebaran Dacrycarpus imbricatus (Blume de Laub. di Bukit Tapak, Cagar Alam Batukahu Bali

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Rajif Iryadi

2017-07-01

Full Text Available Pleaides image is an important asset to obtain data and information with regard to the structure of the vegetation in the forest that are difficult to measure directly as the area is inaccessible and has a large coverage. Dacrycarpus imbricatus (Blume de Laub. is the one of typical plants on the Tapak Hill which has the conservation and economic values. This study aimed to determine the location and distribution of D. imbricatus using Pleaides satellite image that had a high spatial resolution. The determination of site characteristics was conducted by visual interpretation of high resolution satellite imagery Pleiades 2014 and elevation spatial data. Pleaides accuracy in the identification cover of D. imbricatus reached 96.83% and total accuracy mapping reached 93.38% with kappa coefficient of 88.64%. The distribution of D. imbricatus in Tapak Hill showed actual habitat range narrower than of its potential, which was distributed on the elevation of 1,321 – 1,800 m asl with a percentage of 89,52% from its total cover. About 79.29% of the coverage laid on the slope of 25.1 to 55%, whereas the rest on the slope of >25%. This information is important related to sustainability and conservation efforts for this gymnosperm plant in Tapak Hill.

Spin nematics next to spin singlets

Science.gov (United States)

Yokoyama, Yuto; Hotta, Chisa

2018-05-01

We provide a route to generate nematic order in a spin-1/2 system. Unlike the well-known magnon-binding mechanism, our spin nematics requires neither the frustration effect nor spin polarization in a high field or in the vicinity of a ferromagnet, but instead appears next to the spin singlet phase. We start from a state consisting of a quantum spin-1/2 singlet dimer placed on each site of a triangular lattice, and show that interdimer ring exchange interactions efficiently dope the SU(2) triplets that itinerate and interact, easily driving a stable singlet state to either Bose-Einstein condensates or a triplet crystal, some hosting a spin nematic order. A variety of roles the ring exchange serves includes the generation of a bilinear-biquadratic interaction between nearby triplets, which is responsible for the emergent nematic order separated from the singlet phase by a first-order transition.

Emerging bosons with three-body interactions from spin-1 atoms in optical lattices

International Nuclear Information System (INIS)

Mazza, L.; Rizzi, M.; Cirac, J. I.; Lewenstein, M.

2010-01-01

We study two many-body systems of bosons interacting via an infinite three-body contact repulsion in a lattice: a pairs quasicondensate induced by correlated hopping and the discrete version of the Pfaffian wave function. We propose to experimentally realize systems characterized by such interaction by means of a proper spin-1 lattice Hamiltonian: spin degrees of freedom are locally mapped into occupation numbers of emerging bosons, in a fashion similar to spin-1/2 and hardcore bosons. Such a system can be realized with ultracold spin-1 atoms in a Mott insulator with a filling factor of 1. The high versatility of these setups allows us to engineer spin-hopping operators breaking the SU(2) symmetry, as needed to approximate interesting bosonic Hamiltonians with three-body hardcore constraint. For this purpose we combine bichromatic spin-independent superlattices and Raman transitions to induce a different hopping rate for each spin orientation. Finally, we illustrate how our setup could be used to experimentally realize the first setup, that is, the transition to a pairs quasicondensed phase of the emerging bosons. We also report on a route toward the realization of a discrete bosonic Pfaffian wave function and list some open problems for reaching this goal.

Kinetic analysis of spin current contribution to spectrum of electromagnetic waves in spin-1/2 plasma. I. Dielectric permeability tensor for magnetized plasmas

Science.gov (United States)

Andreev, Pavel A.

2017-02-01

The dielectric permeability tensor for spin polarized plasmas is derived in terms of the spin-1/2 quantum kinetic model in six-dimensional phase space. Expressions for the distribution function and spin distribution function are derived in linear approximations on the path of dielectric permeability tensor derivation. The dielectric permeability tensor is derived for the spin-polarized degenerate electron gas. It is also discussed at the finite temperature regime, where the equilibrium distribution function is presented by the spin-polarized Fermi-Dirac distribution. Consideration of the spin-polarized equilibrium states opens possibilities for the kinetic modeling of the thermal spin current contribution in the plasma dynamics.

Measurement of the deep-inelastic spin-dependent structure functions of the proton and neutron at HERA

International Nuclear Information System (INIS)

Beck, D.H.; Filippone, B.W.; Jourdan, J.

1988-01-01

It is possible to measure the deep-inelastic spin-dependent structure functions g 1 /sup p/(x) and g 1 /sup n/(x) for the proton and neutron using internal polarized hydrogen, deuterium, and 3 He targets of polarization 50% and thickness 10 14 to 10 15 cm -2 and the 60 mA longitudinally polarized 30 GeV electron beam in the HERA electron storage ring. The measurement of the deep-inelastic spin-structure of both isospin states of the nucleon at the same kinematics and using the same apparatus allows the Bjorken sum rule to be experimentally checked. In addition, it uniquely constrains the spin distribution of the u and d quarks as a function of x in any model of the nucleon. Possible target and detector configurations are described and an estimate of the accuracy of such a measurement is presented

Dynamic hysteresis behaviors in the kinetic Ising system on triangular lattice

Science.gov (United States)

Kantar, Ersin; Ertaş, Mehmet

2018-04-01

We studied dynamic hysteresis behaviors of the spin-1 Blume-Capel (BC) model in a triangular lattice by means of the effective-field theory (EFT) with correlations and using Glauber-type stochastic dynamics. The effects of the exchange interaction (J), crystal field (D), temperature (T) and oscillating frequency (w) on the hysteresis behaviors of the BC model in a triangular lattice are investigated in detail. Results are compared with some other dynamic studies and quantitatively good agreement is found.

Overexpression of PaFT gene in the wild orchid Phalaenopsis amabilis (L.) Blume

Science.gov (United States)

Semiarti, Endang; Mercuriani, Ixora S.; Rizal, Rinaldi; Slamet, Agus; Utami, Bekti S.; Bestari, Ida A.; Aziz-Purwantoro, Moeljopawiro, S.; Jang, Soenghoe; Machida, Y.; Machida, C.

2015-09-01

To shorten vegetative stage and induce transition from vegetative to reproductive stage in orchids, we overexpressed Phalaenopsis amabilis Flowering LocusT (PaFT) gene under the control of Ubiquitin promoter into protocorm of Indonesian Wild Orchid Phalaenopsis amabilis (L.) Blume. The dynamic expression of vegetative gene Phalaenopsis Homeobox1 (POH1) and flowering time gene PaFT has been analyzed. Accumulation of mRNA was detected in shoot and leaves of both transgenic and non transgenic plants by using Reverse transcriptase-PCR (RT-PCR) with specific gene primers for POH1 and PaFT in 24 months old plants. To analyze the POH1 and PaFT genes, three pairs of degenerate primers PaFT degF1R1, F2R2 and F3R3 that amplified 531 bp PaFT cDNA were used. We detected 700 bp PaFTcDNA from leaves and shoots of transgenic plants, but not in NT plants. POH1 mRNA was detected in plants. PaFT protein consists of Phospatidyl Ethanolamine-Binding Protein (PEBP) in interval base 73-483 and CETS family protein at base 7-519, which are important motif for transmembrane protein. We inserted Ubipro::PaFT/pGAS101 into P. amabilis protocorm using Agrobacterium. Analysis of transgenic plants showed that PaFTmRNA was accumulated in leaves of 12 months after sowing, although it is not detected in non transgeic plants. Compare to the wild type (NT plants), ectopic expression of PaFT shows alter phenotype as follows: 31% normal, 19% with short-wavy leaves, 5% form rosette leaves and 45% produced multishoots. Analysis of protein profiles of trasgenic plants showed that a putative PaFT protein (MW 19,7 kDa) was produced in 1eaves and shoots.This means that at 12 months, POH1 gene expression gradually decreased/negatively regulated, the expression of PaFT gene was activated, although there is no flower initiation yet. Some environmental factors might play a role to induce inflorescens. This experiment is in progress.

D=1 supergravity and spinning particles

International Nuclear Information System (INIS)

Holten, J.W. van.

1995-01-01

In this paper I review the multiplet calculus of N-1, D=1 local supersymmetry with applications to the construction of models for spinning particles in background fields, and models with space-time supersymmetry. New features include a non-linear realization of the local supersymmetry algebra and the coupling to anti-symmetric tensor fields of both odd and even rank. The non-linear realization allows the construction of a D=1 cosmological-constant term, which provides a mass term in the equations of motion. (orig.)

Genetic variability of Amorphophallus muelleri Blume in Java based on Random Amplified Polymorphic DNA

Directory of Open Access Journals (Sweden)

DIYAH MARTANTI

2008-10-01

Full Text Available Amorphophallus muelleri Blume (Araceae is valued for its glucomanan content for use in food industry (healthy diet food, paper industry, pharmacy and cosmetics. The species is triploid (2n=3x=39 and the seed is developed apomictically. The present research is aimed to identify genetic variability of six population of A. muelleri from Java (consisted of 50 accessions using random amplified polymorphic DNA (RAPD. The six populations of the species are: East Java: (1 Silo-Jember, (2 Saradan-Madiun, (3 IPB (cultivated, from Saradan-Madiun, (4 Panti-Jember, (5 Probolinggo; and Central Java: (6 Cilacap. The results showed that five RAPD primers generated 42 scorable bands of which 29 (69.05% were polymorphic. Size of the bands varied from 300bp to 1.5kbp. The 50 accessions of A. muelleri were divided into two main clusters, some of them were grouped based on their populations, and some others were not. The range of individual genetic dissimilarity was from 0.02 to 0.36. The results showed that among six populations investigated, Saradan population showed the highest levels of genetic variation with mean values of na = 1.500+ 0.5061, ne = 1.3174 + 0.3841, PLP = 50% and He = 0, 0.1832+0.2054, whereas Silo-Jember population showed the lowest levels of genetic variation with mean values na = 1.2619+ 0.4450, ne = 1.1890 + 0.3507, PLP = 26.19% and He = 0.1048+0.1887. Efforts to conserve, domesticate, cultivate and improve genetically should be based on the genetic properties of each population and individual within population, especially Saradan population which has the highest levels of genetic variation, need more attention for its conservation.

Magnetization and isothermal magnetic entropy change of a mixed spin-1 and spin-2 Heisenberg superlattice

Science.gov (United States)

Xu, Ping; Du, An

2017-09-01

A superlattice composed of spin-1 and spin-2 with ABAB … structure was described with Heisenberg model. The magnetizations and magnetic entropy changes under different magnetic fields were calculated by the Green's function method. The magnetization compensation phenomenon could be observed by altering the intralayer exchange interactions and the single-ion anisotropies of spins. Along with the temperature increasing, the system in the absence of magnetization compensation shows normal magnetic entropy change and displays a peak near the critical temperature, and yet the system with magnetization compensation shows normal magnetic entropy change near the compensation temperature but inverse magnetic entropy change near the critical temperature. Finally, we illustrated the reasons of different behaviors of magnetic entropy change by analyzing the contributions of two sublattices to the total magnetic entropy change.

Pseudo-spin band in the odd-odd nucleus sup 1 sup 7 sup 2 Lu

CERN Document Server

Venkova, T; Gast, W; Podsvirova, E O; Jäger, H M; Mihailescu, L; Bazzacco, D; Menegazzo, R; Lunardi, S; Alvarez, C R; Ur, C; Martínez, T; Angelis, G D; Axiotis, M; Napoli, D; Urban, W; Rzaca-Urban, T; Frauendorf, S

2003-01-01

High-spin states in the odd-odd nucleus sup 1 sup 7 sup 2 Lu have been populated in a sup 1 sup 7 sup 0 Er( sup 7 Li,5n) reaction and the emitted gamma-radiation was detected with the GASP array. Two sequences of a new identical band have been observed with the transition energies in the favoured and unfavoured sequences being identical within approx 3 keV at low spins and approx 1 keV at high spins over the whole observed spin range. An interpretation as a pseudo-spin singlet band of pi 1/2 sup - [541] x nu 1/2 sup - [420] configuration is proposed. It represents the best example of a pseudo-spin singlet band in normal deformed nuclei known until now.

Can we constrain the maximum value for the spin parameter of the super-massive objects in galactic nuclei without knowing their actual nature?

International Nuclear Information System (INIS)

Bambi, Cosimo

2011-01-01

In 4-dimensional General Relativity, black holes are described by the Kerr solution and are subject to the bound |a * |≤1, where a * is the black hole spin parameter. If current black hole candidates are not the black holes predicted in General Relativity, this bound does not hold and a * might exceed 1. In this Letter, I relax the Kerr black hole hypothesis and I find that the value of the spin parameter of the super-massive black hole candidates in galactic nuclei cannot be higher than about 1.2. A higher spin parameter would not be consistent with a radiative efficiency η>0.15, as observed at least for the most luminous AGN. While a rigorous proof is lacking, I conjecture that the bound |a * |≤1.2 is independent of the exact nature of these objects.

Spin asymmetry $A^d_1$ and the spin-dependent structure function $g^d_1$ of the deuteron at low values of $x$ and $Q^2$

CERN Document Server

Ageev, E.S.; Alexandrov, Yu.; Alexeev, G.D.; Amoroso, A.; Badelek, B.; Balestra, F.; Ball, J.; Baum, G.; Bedfer, Y.; Berglund, P.; Bernet, C.; Bertini, R.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bravar, A.; Bressan, A.; Burtin, E.; Bussa, M.P.; Bytchkov, V.N.; Cerini, L.; Chapiro, A.; Cicuttin, A.; Colantoni, M.; Colavita, A.A.; Costa, S.; Crespo, M.L.; d'Hose, N.; Dalla Torre, S.; Dasgupta, S.S.; De Masi, R.; Dedek, N.; Denisov, O.Yu.; Dhara, L.; Diaz Kavka, V.; Dinkelbach, A.M.; Dolgopolov, A.V.; Donskov, S.V.; Dorofeev, V.A.; Doshita, N.; Duic, V.; Dunnweber, W.; Ehlers, J.; Eversheim, P.D.; Eyrich, W.; Fabro, M.; Faessler, M.; Falaleev, V.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; Finger, M., Jr.; Fischer, H.; Franz, J.; Friedrich, J.M.; Frolov, V.; Fuchs, U.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A.M.; Grajek, O.A.; Grasso, A.; Grube, B.; Grunemaier, A.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Hedicke, S.; Heinsius, F.H.; Hermann, R.; He, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Ijaduola, R.B.; Ilgner, C.; Ioukaev, A.I.; Ishimoto, S.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N.I.; Kabuss, E.; Kalinnikov, V.; Kang, D.; Karstens, F.; Kastaun, W.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Khomutov, N.V.; Kisselev, Yu.; Klein, F.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Komissarov, E.V.; Kondo, K.; Konigsmann, Kay; Konoplyannikov, A.K.; Konorov, I.; Konstantinov, V.F.; Korentchenko, A.S.; Korzenev, A.; Kotzinian, A.M.; Koutchinski, N.A.; Kowalik, K.; Kravchuk, N.P.; Krivokhizhin, G.V.; Kroumchtein, Z.V.; Kuhn, R.; Kunne, F.; Kurek, K.; Ladygin, M.E.; Lamanna, M.; Le Goff, J.M.; Leberig, M.; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.K.; Manuilov, I.V.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Matsuda, T.; Maximov, A.N.; Medved, K.S.; Meyer, W.; Mielech, A.; Mikhailov, Yu.V.; Moinester, M.A.; Nahle, O.; Nassalski, J.; Neliba, S.; Neyret, D.P.; Nikolaenko, V.I.; Nozdrin, A.A.; Obraztsov, V.F.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Panzieri, D.; Paul, S.; Pereira, H.D.; Peshekhonov, D.V.; Peshekhonov, V.D.; Piragino, G.; Platchkov, S.; Platzer, K.; Pochodzalla, J.; Polyakov, V.A.; Popov, A.A.; Pretz, J.; Quintans, C.; Ramos, S.; Rebourgeard, P.C.; Reicherz, G.; Reymann, J.; Rith, K.; Rozhdestvensky, A.M.; Rondio, E.; Sadovski, A.B.; Saller, E.; Samoylenko, V.D.; Sandacz, A.; Sans, M.; Sapozhnikov, M.G.; Savin, Igor A.; Schiavon, P.; Schill, C.; Schmidt, T.; Schmitt, H.; Schmitt, L.; Shevchenko, O.Yu.; Shishkin, A.A.; Siebert, H.-W.; Sinha, L.; Sissakian, A.N.; Skachkova, A.; Slunecka, M.; Smirnov, G.I.; Sozzi, F.; Sugonyaev, V.P.; Srnka, A.; Stinzing, F.; Stolarski, M.; Sulc, M.; Sulej, R.; Takabayashi, N.; Tchalishev, V.V.; Tessarotto, F.; Teufel, A.; Thers, D.; Tkatchev, L.G.; Toeda, T.; Tretyak, V.I.; Trusov, Sergey V.; Varanda, M.; Virius, M.; Vlassov, N.V.; Wagner, M.; Webb, R.; Weise, E.; Weitzel, Q.; Wiedner, U.; Wiesmann, M.; Windmolders, R.; Wirth, S.; Wislicki, W.; Zanetti, A.M.; Zaremba, K.; Zhao, J.; Ziegler, R.; Zvyagin, A.

2007-01-01

We present a precise measurement of the deuteron longitudinal spin asymmetry $A_1^d$ and of the deuteron spin-dependent structure function $g_1^d$ at $Q^2 < $ 1~(GeV/$c$)$^2$ and $4\\cdot$10$^{-5} < x < $~2.5$\\cdot$10$^{-2}$ based on the data collected by the COMPASS experiment at CERN during the years 2002 and 2003. The statistical precision is tenfold better than that of the previous measurement in this region. The measured $A_1^d$ and $g_1^d$ are found to be consistent with zero in the whole range of $x$.

Improved spin wave theory: An application to the spin-1/2 antiferromagnetic Heisenberg model on a square lattice

International Nuclear Information System (INIS)

Tao, Ruibao.

1991-09-01

A method is developed to make a Bose transformation which is restricted in proper space. A self-consistent independent spin wave representation (SCISWR) is found for two dimensional isotropic antiferromagnet of Heisenberg square lattices. In the SCISWR, we have successfully done the renormalization from both the dynamic and kinematic interaction and calculated the corrections from the correlations of the nearest neighbour and next nearest neighbour sites. An anisotropic excitation energy of spin wave in improper space is found self-consistently and has a gap. The difficulty of divergence appearing from higher order perturbation terms in the conventional spin wave theory has been overcome and the convergence in our approach seems quite good. We find the energy of ground state E approx. -0.659 in low order approximation and the magnetization of sublattice M z = 0.430 x (N/2) for system with spin 1/2. It is also proved that a physical spin excitation restricted in proper space is still isotropic and has no gap. (author). 17 refs

Master actions for massive spin-3 particles in D = 2 + 1

Energy Technology Data Exchange (ETDEWEB)

Leite Mendonca, Elias; Dalmazi, Denis [UNESP, Campus de Guaratingueta, DFQ, Guaratingueta, SP (Brazil)

2016-04-15

We present here a relationship between massive self-dual models for spin-3 particles in D = 2 + 1 via the master action procedure. Starting with a first-order model (in the derivatives) S{sub SD(1)} we have constructed a master action which interpolates between a sequence of four self-dual models S{sub SD(i)} where i = 1, 2, 3, 4. By analyzing the particle content of the mixing terms, we give additional arguments that explain why it is apparently impossible to jump from the fourth-order model to a higher-order model. We have also analyzed similarities and differences between the fourth-order K-term in the spin-2 case and the analogous fourth-order term in the spin-3 context. (orig.)

Non-adiabatic Landau-Zener transitions in low-spin molecular magnet V sub 1 sub 5

CERN Document Server

Chiorescu, I; Müller, A; Bögge, H; Barbara, B

2000-01-01

The V sub 1 sub 5 polyoxovanadate molecule is made of 15 spins ((1)/(2)) with antiferromagnetic couplings. It belongs to the class of molecules with very large Hilbert space dimension (2 sup 1 sup 5 in V sub 1 sub 5 , 10 sup 8 in Mn sub 1 sub 2 -AC). It is a low spin/large molecule with spin S=((1)/(2)). Contrary to large spins/large molecules of the Mn sub 1 sub 2 -AC type, V sub 1 sub 5 has no energy barrier against spin rotation. Magnetization measurements have been performed and despite the absence of a barrier, magnetic hysteresis is observed over a timescale of several seconds. This new phenomenon characterized by a 'butterfly' hysteresis loop is due to the effect of the environment on the quantum rotation of the entangled 15 spins of the molecule, in which the phonon density of states is not at its equilibrium (phonon bottleneck).

Determination of the Pt spin diffusion length by spin-pumping and spin Hall effect

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wei; Pearson, John E.; Hoffmann, Axel [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Vlaminck, Vincent [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Colegio de Ciencias e Ingenería, Universidad San Fransciso de Quito, Quito (Ecuador); Divan, Ralu [Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States); Bader, Samuel D. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States)

2013-12-09

The spin diffusion length of Pt at room temperature and at 8 K is experimentally determined via spin pumping and spin Hall effect in permalloy/Pt bilayers. Voltages generated during excitation of ferromagnetic resonance from the inverse spin Hall effect and anisotropic magnetoresistance effect were investigated with a broadband approach. Varying the Pt layer thickness gives rise to an evolution of the voltage line shape due to the superposition of the above two effects. By studying the ratio of the two voltage components with the Pt layer thickness, the spin diffusion length of Pt can be directly extracted. We obtain a spin diffusion length of ∼1.2 nm at room temperature and ∼1.6 nm at 8 K.

Giant spin Hall angle from topological insulator BixSe(1 - x) thin films

Science.gov (United States)

Dc, Mahendra; Jamali, Mahdi; Chen, Junyang; Hickey, Danielle; Zhang, Delin; Zhao, Zhengyang; Li, Hongshi; Quarterman, Patrick; Lv, Yang; Mkhyon, Andre; Wang, Jian-Ping

Investigation on the spin-orbit torque (SOT) from large spin-orbit coupling materials has been attracting interest because of its low power switching of the magnetization and ultra-fast driving of the domain wall motion that can be used in future spin based memory and logic devices. We investigated SOT from topological insulator BixSe(1 - x) thin film in BixSe(1 - x) /CoFeB heterostructure by using the dc planar Hall method, where BixSe(1 - x) thin films were prepared by a unique industry-compatible deposition process. The angle dependent Hall resistance was measured in the presence of a rotating external in-plane magnetic field at bipolar currents. The spin Hall angle (SHA) from this BixSe(1 - x) thin film was found to be as large as 22.41, which is the largest ever reported at room temperature (RT). The giant SHA and large spin Hall conductivity (SHC) make this BixSe(1 - x) thin film a very strong candidate as an SOT generator in SOT based memory and logic devices.

Statistical mechanics of relativistic spin-1 bosons in a magnetic field

International Nuclear Information System (INIS)

Daicic, J.; Frankel, N.E.

1993-01-01

This paper investigates the statistical mechanics of a gas of spin-1 particles with pair creation in a homogeneous magnetic field. It is shown that expansions for the thermodynamic potential and magnetization in fields below the mass scale of the constituent particles are well behaved. However, when the field is at or above the mass scale, an intrinsic pathology of the single-particle energy spectrum manifests itself in the statistical mechanics of the system. Whilst for the spin-0 and spin-1/2 analog of this system there seemed to be no barrier ab initio to the field strength, the nature of the vacuum, and the role of interactions, were always borne in mind as matters to be considered in a high-order treatment, particularly when the field was at or above the mass scale. In the spin-1 case, the pathology in the single-particle energy spectrum heralds this from the beginning, and seems to be a warning that a single particle non-interacting picture of physics at high energies needs some reconsideration. 10 refs

Equations of motion of test particles for solving the spin-dependent Boltzmann–Vlasov equation

Energy Technology Data Exchange (ETDEWEB)

Xia, Yin [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Science, Beijing 100049 (China); Xu, Jun, E-mail: xujun@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Li, Bao-An [Department of Physics and Astronomy, Texas A& M University-Commerce, Commerce, TX 75429-3011 (United States); Department of Applied Physics, Xi' an Jiao Tong University, Xi' an 710049 (China); Shen, Wen-Qing [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

2016-08-10

A consistent derivation of the equations of motion (EOMs) of test particles for solving the spin-dependent Boltzmann–Vlasov equation is presented. The resulting EOMs in phase space are similar to the canonical equations in Hamiltonian dynamics, and the EOM of spin is the same as that in the Heisenburg picture of quantum mechanics. Considering further the quantum nature of spin and choosing the direction of total angular momentum in heavy-ion reactions as a reference of measuring nucleon spin, the EOMs of spin-up and spin-down nucleons are given separately. The key elements affecting the spin dynamics in heavy-ion collisions are identified. The resulting EOMs provide a solid foundation for using the test-particle approach in studying spin dynamics in heavy-ion collisions at intermediate energies. Future comparisons of model simulations with experimental data will help to constrain the poorly known in-medium nucleon spin–orbit coupling relevant for understanding properties of rare isotopes and their astrophysical impacts.

Approximate energy correction for particle number summetry breaking in constrained Hartree-Fock plus BCS calculations

International Nuclear Information System (INIS)

Redon, N.; Meyer, J.; Meyer, M.

1989-01-01

An approximate restoration of the particle number symmetry, a la Lipkin-Nogami, is numerically investigated in the context of Constrained Hartree-Fock plus BCS calculations. Its effect is assessed in a variety of physical situations like potential energy landscapes in transitional nuclei, shape isomerism at low spin and fission barriers of actinide nuclei

X- and γ-ray interaction characteristics of Griffith, Alderson, Frigerio, Goodman and Rossi tissue substitutes

International Nuclear Information System (INIS)

Singh, V. P.; Badiger, N. M.; Vega C, H. R.

2015-10-01

Detailed information of radiation interaction, exposure and dose delivery to tissue substitutes is necessary for various branches of radiation physics. In the present investigation X- and γ-ray interaction characteristics of some tissue substitutes such as Griffith, Alderson, Frigerio, Goodman and Rossi have been studied and compared with standard tissues. Effective atomic numbers and air-kerma have been computed using mass attenuation coefficients and mass energy-absorption coefficients, respectively. Energy-absorption buildup factors for photon energy 0.015 to 15 MeV up to 40 mean free path were calculated using G-P fitting method. These investigations provide further information on the X- and γ-ray interaction of tissue substitutes for various applications in radiation physics and medical physics. (Author)

X- and γ-ray interaction characteristics of Griffith, Alderson, Frigerio, Goodman and Rossi tissue substitutes

Energy Technology Data Exchange (ETDEWEB)

Singh, V. P.; Badiger, N. M. [Karnatak University, Department of Physics, Dharwad-580003, Karnataka (India); Vega C, H. R., E-mail: kudphyvps@rediffmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

2015-10-15

Detailed information of radiation interaction, exposure and dose delivery to tissue substitutes is necessary for various branches of radiation physics. In the present investigation X- and γ-ray interaction characteristics of some tissue substitutes such as Griffith, Alderson, Frigerio, Goodman and Rossi have been studied and compared with standard tissues. Effective atomic numbers and air-kerma have been computed using mass attenuation coefficients and mass energy-absorption coefficients, respectively. Energy-absorption buildup factors for photon energy 0.015 to 15 MeV up to 40 mean free path were calculated using G-P fitting method. These investigations provide further information on the X- and γ-ray interaction of tissue substitutes for various applications in radiation physics and medical physics. (Author)

Adiabatic demagnetization of the antiferromagnetic spin-1/2 Heisenberg hexagonal cluster

International Nuclear Information System (INIS)

Deb, Moumita; Ghosh, Asim Kumar

2016-01-01

Exact analytic expressions of eigenvalues of the antiferromagnetic spin-1/2 Heisenberg hexagon in the presence of uniform magnetic field have been obtained. Magnetization process, nature of isentrops and properties of magneto caloric effect in terms of adiabatic demagnetization have been investigated. Theoretical results have been used to study the magneto caloric effect of the spin-1/2 Heisenberg hexagonal compound Cu_3WO_6.

Noise in tunneling spin current across coupled quantum spin chains

Science.gov (United States)

Aftergood, Joshua; Takei, So

2018-01-01

We theoretically study the spin current and its dc noise generated between two spin-1 /2 spin chains weakly coupled at a single site in the presence of an over-population of spin excitations and a temperature elevation in one subsystem relative to the other, and we compare the corresponding transport quantities across two weakly coupled magnetic insulators hosting magnons. In the spin chain scenario, we find that applying a temperature bias exclusively leads to a vanishing spin current and a concomitant divergence in the spin Fano factor, defined as the spin current noise-to-signal ratio. This divergence is shown to have an exact analogy to the physics of electron scattering between fractional quantum Hall edge states and not to arise in the magnon scenario. We also reveal a suppression in the spin current noise that exclusively arises in the spin chain scenario due to the fermion nature of the spin-1/2 operators. We discuss how the spin Fano factor may be extracted experimentally via the inverse spin Hall effect used extensively in spintronics.

Spin-0± portal induced Dark Matter

Science.gov (United States)

Dutta, Sukanta; Goyal, Ashok; Saini, Lalit Kumar

2018-02-01

Standard model (SM) spin-zero singlets are constrained through their di-Bosonic decay channels via an effective coupling induced by a vector-like quark (VLQ) loop at the LHC for √{s}=13 TeV. These spin-zero resonances are then considered as portals for scalar, vector or fermionic dark matter particle interactions with SM gauge bosons. We find that the model is validated with respect to the observations from LHC data and from cosmology, indirect and direct detection experiments for an appreciable range of scalar, vector and fermionic DM masses greater than 300 GeV and VLQ masses ≥ 400 GeV, corresponding to the three choice of portal masses 270 GeV, 500 GeV and 750 GeV respectively.

Signatures of a gearwheel quantum spin liquid in a spin-1/2 pyrochlore molybdate Heisenberg antiferromagnet

Science.gov (United States)

Iqbal, Yasir; Müller, Tobias; Riedl, Kira; Reuther, Johannes; Rachel, Stephan; Valentí, Roser; Gingras, Michel J. P.; Thomale, Ronny; Jeschke, Harald O.

2017-12-01

We theoretically investigate the low-temperature phase of the recently synthesized Lu2Mo2O5N2 material, an extraordinarily rare realization of a S =1 /2 three-dimensional pyrochlore Heisenberg antiferromagnet in which Mo5 + are the S =1 /2 magnetic species. Despite a Curie-Weiss temperature (ΘCW) of -121 (1 ) K, experiments have found no signature of magnetic ordering or spin freezing down to T*≈0.5 K. Using density functional theory, we find that the compound is well described by a Heisenberg model with exchange parameters up to third nearest neighbors. The analysis of this model via the pseudofermion functional renormalization group method reveals paramagnetic behavior down to a temperature of at least T =| ΘCW|/100 , in agreement with the experimental findings hinting at a possible three-dimensional quantum spin liquid. The spin susceptibility profile in reciprocal space shows momentum-dependent features forming a "gearwheel" pattern, characterizing what may be viewed as a molten version of a chiral noncoplanar incommensurate spiral order under the action of quantum fluctuations. Our calculated reciprocal space susceptibility maps provide benchmarks for future neutron scattering experiments on single crystals of Lu2Mo2O5N2 .

Muonium spin exchange in spin-polarized media: Spin-flip and -nonflip collisions

International Nuclear Information System (INIS)

Senba, M.

1994-01-01

The transverse relaxation of the muon spin in muonium due to electron spin exchange with a polarized spin-1/2 medium is investigated. Stochastic calculations, which assume that spin exchange is a Poisson process, are carried out for the case where the electron spin polarization of the medium is on the same axis as the applied field. Two precession signals of muonium observed in intermediate fields (B>30 G) are shown to have different relaxation rates which depend on the polarization of the medium. Furthermore, the precession frequencies are shifted by an amount which depends on the spin-nonflip rate. From the two relaxation rates and the frequency shift in intermediate fields, one can determine (i) the encounter rate of muonium and the paramagnetic species, (ii) the polarization of the medium, and most importantly (iii) the quantum-mechanical phase shift (and its sign) associated with the potential energy difference between electron singlet and triplet encounters. Effects of spin-nonflip collisions on spin dynamics are discussed for non-Poisson as well as Poisson processes. In unpolarized media, the time evolution of the muon spin in muonium is not influenced by spin-nonflip collisions, if the collision process is Poissonian. This seemingly obvious statement is not true anymore in non-Poissonian processes, i.e., it is necessary to specify both spin-flip and spin-nonflip rates to fully characterize spin dynamics

Spin-1 diquark contributing to the formation of tetraquarks in light mesons

Energy Technology Data Exchange (ETDEWEB)

Kim, Hungchong [Korea Aerospace University, Research Institute of Basic Science, Goyang (Korea, Republic of); Cheoun, Myung-Ki [Soongsil University, Department of Physics, Seoul (Korea, Republic of); Kim, K.S. [Korea Aerospace University, School of Liberal Arts and Science, Goyang (Korea, Republic of)

2017-03-15

We apply a mixing framework to the light-meson systems and examine tetraquark possibility in the scalar channel. In the diquark-antidiquark model, a scalar diquark is a compact object when its color and flavor structures are in (anti 3{sub c}, anti 3{sub f}). Assuming that all the quarks are in an S-wave, the spin-0 tetraquark formed out of this scalar diquark has only one spin configuration, vertical stroke J,J{sub 12},J{sub 34} right angle = vertical stroke 000 right angle, where J is the spin of the tetraquark, J{sub 12} the diquark spin, J{sub 34} the antidiquark spin. In this construction of the scalar tetraquark, we notice that another compact diquark with spin-1 in (6{sub c}, anti 3{sub f}) can be used although it is less compact than the scalar diquark. The spin-0 tetraquark constructed from this vector diquark leads to the spin configuration vertical stroke J,J{sub 12},J{sub 34} right angle = vertical stroke 011 right angle. The two configurations, vertical stroke 000 right angle and vertical stroke 011 right angle, are found to mix strongly through the color-spin interaction. The physical states can be identified with certain mixtures of the two configurations which diagonalize the hyperfine masses of the color-spin interaction. Matching these states to two scalar resonances a{sub 0}(980), a{sub 0}(1450) or to K{sup *}{sub 0}(800), K{sup *}{sub 0}(1430) depending on the isospin channel, we find that their mass splittings are qualitatively consistent with the hyperfine mass splittings, which can support their tetraquark structure. To test our mixing scheme further, we also construct the tetraquarks for J = 1, J = 2 with the spin configurations vertical stroke 111 right angle and vertical stroke 2011 right angle, and we discuss possible candidates in the physical spectrum. (orig.)

Dynamic phase transitions of the Blume–Emery–Griffiths model under an oscillating external magnetic field by the path probability method

Energy Technology Data Exchange (ETDEWEB)

Ertaş, Mehmet, E-mail: mehmetertas@erciyes.edu.tr; Keskin, Mustafa

2015-03-01

By using the path probability method (PPM) with point distribution, we study the dynamic phase transitions (DPTs) in the Blume–Emery–Griffiths (BEG) model under an oscillating external magnetic field. The phases in the model are obtained by solving the dynamic equations for the average order parameters and a disordered phase, ordered phase and four mixed phases are found. We also investigate the thermal behavior of the dynamic order parameters to analyze the nature dynamic transitions as well as to obtain the DPT temperatures. The dynamic phase diagrams are presented in three different planes in which exhibit the dynamic tricritical point, double critical end point, critical end point, quadrupole point, triple point as well as the reentrant behavior, strongly depending on the values of the system parameters. We compare and discuss the dynamic phase diagrams with dynamic phase diagrams that were obtained within the Glauber-type stochastic dynamics based on the mean-field theory. - Highlights: • Dynamic magnetic behavior of the Blume–Emery–Griffiths system is investigated by using the path probability method. • The time variations of average magnetizations are studied to find the phases. • The temperature dependence of the dynamic magnetizations is investigated to obtain the dynamic phase transition points. • We compare and discuss the dynamic phase diagrams with dynamic phase diagrams that were obtained within the Glauber-type stochastic dynamics based on the mean-field theory.

Dynamic phase transitions of the Blume–Emery–Griffiths model under an oscillating external magnetic field by the path probability method

International Nuclear Information System (INIS)

Ertaş, Mehmet; Keskin, Mustafa

2015-01-01

By using the path probability method (PPM) with point distribution, we study the dynamic phase transitions (DPTs) in the Blume–Emery–Griffiths (BEG) model under an oscillating external magnetic field. The phases in the model are obtained by solving the dynamic equations for the average order parameters and a disordered phase, ordered phase and four mixed phases are found. We also investigate the thermal behavior of the dynamic order parameters to analyze the nature dynamic transitions as well as to obtain the DPT temperatures. The dynamic phase diagrams are presented in three different planes in which exhibit the dynamic tricritical point, double critical end point, critical end point, quadrupole point, triple point as well as the reentrant behavior, strongly depending on the values of the system parameters. We compare and discuss the dynamic phase diagrams with dynamic phase diagrams that were obtained within the Glauber-type stochastic dynamics based on the mean-field theory. - Highlights: • Dynamic magnetic behavior of the Blume–Emery–Griffiths system is investigated by using the path probability method. • The time variations of average magnetizations are studied to find the phases. • The temperature dependence of the dynamic magnetizations is investigated to obtain the dynamic phase transition points. • We compare and discuss the dynamic phase diagrams with dynamic phase diagrams that were obtained within the Glauber-type stochastic dynamics based on the mean-field theory

Observation of overlapping spin-1 and spin-3 D0K- resonances at mass 2.86 GeV/c2.

Science.gov (United States)

Aaij, R; Adeva, B; Adinolfi, M; Affolder, A; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Anderson, J; Andreassen, R; Andreotti, M; Andrews, J E; Appleby, R B; Aquines Gutierrez, O; Archilli, F; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Baalouch, M; Bachmann, S; Back, J J; Badalov, A; Baesso, C; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Batozskaya, V; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Belogurov, S; Belous, K; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bettler, M-O; van Beuzekom, M; Bien, A; Bifani, S; Bird, T; Bizzeti, A; Bjørnstad, P M; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borgia, A; Borsato, M; Bowcock, T J V; Bowen, E; Bozzi, C; Brambach, T; van den Brand, J; Bressieux, J; Brett, D; Britsch, M; Britton, T; Brodzicka, J; Brook, N H; Brown, H; Bursche, A; Busetto, G; Buytaert, J; Cadeddu, S; Calabrese, R; Calvi, M; Calvo Gomez, M; Campana, P; Campora Perez, D; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carson, L; Carvalho Akiba, K; Casse, G; Cassina, L; Castillo Garcia, L; Cattaneo, M; Cauet, Ch; Cenci, R; Charles, M; Charpentier, Ph; Chefdeville, M; Chen, S; Cheung, S-F; Chiapolini, N; Chrzaszcz, M; Ciba, K; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coco, V; Cogan, J; Cogneras, E; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombes, M; Coquereau, S; Corti, G; Corvo, M; Counts, I; Couturier, B; Cowan, G A; Craik, D C; Cruz Torres, M; Cunliffe, S; Currie, R; D'Ambrosio, C; Dalseno, J; David, P; David, P N Y; Davis, A; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Silva, W; De Simone, P; Decamp, D; Deckenhoff, M; Del Buono, L; Déléage, N; Derkach, D; Deschamps, O; Dettori, F; Di Canto, A; Dijkstra, H; Donleavy, S; Dordei, F; Dorigo, M; Dosil Suárez, A; Dossett, D; Dovbnya, A; Dreimanis, K; Dujany, G; Dupertuis, F; Durante, P; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Easo, S; Egede, U; Egorychev, V; Eidelman, S; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; El Rifai, I; Elsasser, Ch; Ely, S; Esen, S; Evans, H-M; Evans, T; Falabella, A; Färber, C; Farinelli, C; Farley, N; Farry, S; Fay, Rf; Ferguson, D; Fernandez Albor, V; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fiore, M; Fiorini, M; Firlej, M; Fitzpatrick, C; Fiutowski, T; Fontana, M; Fontanelli, F; Forty, R; Francisco, O; Frank, M; Frei, C; Frosini, M; Fu, J; Furfaro, E; Gallas Torreira, A; Galli, D; Gallorini, S; Gambetta, S; Gandelman, M; Gandini, P; Gao, Y; García Pardiñas, J; Garofoli, J; Garra Tico, J; Garrido, L; Gaspar, C; Gauld, R; Gavardi, L; Gavrilov, G; Geraci, A; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gianelle, A; Gianì, S; Gibson, V; Giubega, L; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gotti, C; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graziani, G; Grecu, A; Greening, E; Gregson, S; Griffith, P; Grillo, L; Grünberg, O; Gui, B; Gushchin, E; Guz, Yu; Gys, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hamilton, B; Hampson, T; Han, X; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; He, J; Head, T; Heijne, V; Hennessy, K; Henrard, P; Henry, L; Hernando Morata, J A; van Herwijnen, E; Heß, M; Hicheur, A; Hill, D; Hoballah, M; Hombach, C; Hulsbergen, W; Hunt, P; Hussain, N; Hutchcroft, D; Hynds, D; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jalocha, J; Jans, E; Jaton, P; Jawahery, A; Jing, F; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Jurik, N; Kaballo, M; Kandybei, S; Kanso, W; Karacson, M; Karbach, T M; Karodia, S; Kelsey, M; Kenyon, I R; Ketel, T; Khanji, B; Khurewathanakul, C; Klaver, S; Klimaszewski, K; Kochebina, O; Kolpin, M; Komarov, I; Koopman, R F; Koppenburg, P; Korolev, M; Kozlinskiy, A; Kravchuk, L; Kreplin, K; Kreps, M; Krocker, G; Krokovny, P; Kruse, F; Kucewicz, W; Kucharczyk, M; Kudryavtsev, V; Kurek, K; Kvaratskheliya, T; La Thi, V N; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lambert, R W; Lanfranchi, G; Langenbruch, C; Langhans, B; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J-P; Lefèvre, R; Leflat, A; Lefrançois, J; Leo, S; Leroy, O; Lesiak, T; Leverington, B; Li, Y; Likhomanenko, T; Liles, M; Lindner, R; Linn, C; Lionetto, F; Liu, B; Lohn, S; Longstaff, I; Lopes, J H; Lopez-March, N; Lowdon, P; Lu, H; Lucchesi, D; Luo, H; Lupato, A; Luppi, E; Lupton, O; Machefert, F; Machikhiliyan, I V; Maciuc, F; Maev, O; Malde, S; Malinin, A; Manca, G; Mancinelli, G; Mapelli, A; Maratas, J; Marchand, J F; Marconi, U; Marin Benito, C; Marino, P; Märki, R; Marks, J; Martellotti, G; Martens, A; Martín Sánchez, A; Martinelli, M; Martinez Santos, D; Martinez Vidal, F; Martins Tostes, D; Massafferri, A; Matev, R; Mathe, Z; Matteuzzi, C; Mazurov, A; McCann, M; McCarthy, J; McNab, A; McNulty, R; McSkelly, B; Meadows, B; Meier, F; Meissner, M; Merk, M; Milanes, D A; Minard, M-N; Moggi, N; Molina Rodriguez, J; Monteil, S; Morandin, M; Morawski, P; Mordà, A; Morello, M J; Moron, J; Morris, A-B; Mountain, R; Muheim, F; Müller, K; Mussini, M; Muster, B; Naik, P; Nakada, T; Nandakumar, R; Nasteva, I; Needham, M; Neri, N; Neubert, S; Neufeld, N; Neuner, M; Nguyen, A D; Nguyen, T D; Nguyen-Mau, C; Nicol, M; Niess, V; Niet, R; Nikitin, N; Nikodem, T; Novoselov, A; O'Hanlon, D P; Oblakowska-Mucha, A; Obraztsov, V; Oggero, S; Ogilvy, S; Okhrimenko, O; Oldeman, R; Onderwater, G; Orlandea, M; Otalora Goicochea, J M; Owen, P; Oyanguren, A; Pal, B K; Palano, A; Palombo, F; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Pappalardo, L L; Parkes, C; Parkinson, C J; Passaleva, G; Patel, G D; Patel, M; Patrignani, C; Pazos Alvarez, A; Pearce, A; Pellegrino, A; Pepe Altarelli, M; Perazzini, S; Perez Trigo, E; Perret, P; Perrin-Terrin, M; Pescatore, L; Pesen, E; Petridis, K; Petrolini, A; Picatoste Olloqui, E; Pietrzyk, B; Pilař, T; Pinci, D; Pistone, A; Playfer, S; Plo Casasus, M; Polci, F; Poluektov, A; Polycarpo, E; Popov, A; Popov, D; Popovici, B; Potterat, C; Price, E; Prisciandaro, J; Pritchard, A; Prouve, C; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Rachwal, B; Rademacker, J H; Rakotomiaramanana, B; Rama, M; Rangel, M S; Raniuk, I; Rauschmayr, N; Raven, G; Reichert, S; Reid, M M; Dos Reis, A C; Ricciardi, S; Richards, S; Rihl, M; Rinnert, K; Rives Molina, V; Roa Romero, D A; Robbe, P; Rodrigues, A B; Rodrigues, E; Rodriguez Perez, P; Roiser, S; Romanovsky, V; Romero Vidal, A; Rotondo, M; Rouvinet, J; Ruf, T; Ruffini, F; Ruiz, H; Ruiz Valls, P; Saborido Silva, J J; Sagidova, N; Sail, P; Saitta, B; Salustino Guimaraes, V; Sanchez Mayordomo, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santovetti, E; Sarti, A; Satriano, C; Satta, A; Saunders, D M; Savrie, M; Savrina, D; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmidt, B; Schneider, O; Schopper, A; Schune, M-H; Schwemmer, R; Sciascia, B; Sciubba, A; Seco, M; Semennikov, A; Sepp, I; Serra, N; Serrano, J; Sestini, L; Seyfert, P; Shapkin, M; Shapoval, I; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, V; Shires, A; Silva Coutinho, R; Simi, G; Sirendi, M; Skidmore, N; Skwarnicki, T; Smith, N A; Smith, E; Smith, E; Smith, J; Smith, M; Snoek, H; Sokoloff, M D; Soler, F J P; Soomro, F; Souza, D; Souza De Paula, B; Spaan, B; Sparkes, A; Spradlin, P; Sridharan, S; Stagni, F; Stahl, M; Stahl, S; Steinkamp, O; Stenyakin, O; Stevenson, S; Stoica, S; Stone, S; Storaci, B; Stracka, S; Straticiuc, M; Straumann, U; Stroili, R; Subbiah, V K; Sun, L; Sutcliffe, W; Swientek, K; Swientek, S; Syropoulos, V; Szczekowski, M; Szczypka, P; Szilard, D; Szumlak, T; T'Jampens, S; Teklishyn, M; Tellarini, G; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Tolk, S; Tomassetti, L; Tonelli, D; Topp-Joergensen, S; Torr, N; Tournefier, E; Tourneur, S; Tran, M T; Tresch, M; Tsaregorodtsev, A; Tsopelas, P; Tuning, N; Ubeda Garcia, M; Ukleja, A; Ustyuzhanin, A; Uwer, U; Vagnoni, V; Valenti, G; Vallier, A; Vazquez Gomez, R; Vazquez Regueiro, P; Vázquez Sierra, C; Vecchi, S; Velthuis, J J; Veltri, M; Veneziano, G; Vesterinen, M; Viaud, B; Vieira, D; Vieites Diaz, M; Vilasis-Cardona, X; Vollhardt, A; Volyanskyy, D; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; Voss, H; de Vries, J A; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wandernoth, S; Wang, J; Ward, D R; Watson, N K; Websdale, D; Whitehead, M; Wicht, J; Wiedner, D; Wilkinson, G; Williams, M P; Williams, M; Wilson, F F; Wimberley, J; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wright, S; Wu, S; Wyllie, K; Xie, Y; Xing, Z; Xu, Z; Yang, Z; Yuan, X; Yushchenko, O; Zangoli, M; Zavertyaev, M; Zhang, L; Zhang, W C; Zhang, Y; Zhelezov, A; Zhokhov, A; Zhong, L; Zvyagin, A

2014-10-17

The resonant substructure of B(s)(0) → D(0)K(-)π(+) decays is studied using a data sample corresponding to an integrated luminosity of 3.0 fb(-1) of pp collision data recorded by the LHCb detector. An excess at m(D(0)K(-))≈ 2.86 GeV/c(2) is found to be an admixture of spin-1 and spin-3 resonances. Therefore, the D(sJ)*(2860)(-) state previously observed in inclusive e(+)e(-) → D(0)K(-)X and pp → D(0)K(-)X processes consists of at least two particles. This is the first observation of a heavy flavored spin-3 resonance, and the first time that any spin-3 particle has been seen to be produced in B decays. The masses and widths of the new states and of the D(s2)*(2573)(-) meson are measured, giving the most precise determinations to date.

Magnetocaloric effect in quantum spin-s chains

Directory of Open Access Journals (Sweden)

A. Honecker

2009-01-01

Full Text Available We compute the entropy of antiferromagnetic quantum spin-s chains in an external magnetic field using exact diagonalization and Quantum Monte Carlo simulations. The magnetocaloric effect, i. e., temperature variations during adiabatic field changes, can be derived from the isentropes. First, we focus on the example of the spin-s=1 chain and show that one can cool by closing the Haldane gap with a magnetic field. We then move to quantum spin-s chains and demonstrate linear scaling with s close to the saturation field. In passing, we propose a new method to compute many low-lying excited states using the Lanczos recursion.

Influence of External Magnetic Fields on Tunneling of Spin-1 Bose Condensate

International Nuclear Information System (INIS)

Yu Zhaoxian; Jiao Zhiyong; Sun Jinzuo

2005-01-01

In this letter, we have studied the influence of the external magnetic fields on tunneling of the spin-1 Bose condensate. We find that the population transfer between spin-0 and spin-±1 exhibits the step structure under the external cosinusoidal magnetic field and a combination of static and cosinusoidal one, respectively. Compared with the longitudinal component of the external magnetic field, the smaller the transverse component of the magnetic field is, the larger the time scale of exhibiting the step structure does. The tunneling current may exhibit periodically oscillation behavior when the ratio of the transverse component of the magnetic field is smaller than that of the longitudinal component, otherwise it exhibits a damply oscillating behavior. This means that the dynamical spin localization can be adjusted by the external magnetic fields.

Thermal properties of the mixed spin-1 and spin-3/2 Ising ferrimagnetic system with two different random single-ion anisotropies

Science.gov (United States)

Pereira, J. R. V.; Tunes, T. M.; de Arruda, A. S.; Godoy, M.

2018-06-01

In this work, we have performed Monte Carlo simulations to study a mixed spin-1 and spin-3/2 Ising ferrimagnetic system on a square lattice with two different random single-ion anisotropies. This lattice is divided in two interpenetrating sublattices with spins SA = 1 in the sublattice A and SB = 3 / 2 in the sublattice B. The exchange interaction between the spins on the sublattices is antiferromagnetic (J single-ion anisotropies, DiA and DjB , on the sublattices A and B, respectively. We have determined the phase diagram of the model in the critical temperature Tc versus strength of the random single-ion anisotropy D plane and we shown that it exhibits only second-order phase transition lines. We also shown that this system displays compensation temperatures for some cases of the random single-ion distribution.

Constraints on Black Hole Spin in a Sample of Broad Iron Line AGN

Science.gov (United States)

Brenneman, Laura W.; Reynolds, Christopher S.

2008-01-01

We present a uniform X-ray spectral analysis of nine type-1 active galactic nuclei (AGN) that have been previously found to harbor relativistically broadened iron emission lines. We show that the need for relativistic effects in the spectrum is robust even when one includes continuum "reflection" from the accretion disk. We then proceed to model these relativistic effects in order to constrain the spin of the supermassive black holes in these AGN. Our principal assumption, supported by recent simulations of geometrically-thin accretion disks, is that no iron line emission (or any associated Xray reflection features) can originate from the disk within the innermost stable circular orbit. Under this assumption, which tends to lead to constraints in the form of lower limits on the spin parameter, we obtain non-trivial spin constraints on five AGN. The spin parameters of these sources range from moderate (a approximates 0.6) to high (a > 0.96). Our results allow, for the first time, an observational constraint on the spin distribution function of local supermassive black holes. Parameterizing this as a power-law in dimensionless spin parameter (f(a) varies as absolute value of (a) exp zeta), we present the probability distribution for zeta implied by our results. Our results suggest 90% and 95% confidence limits of zeta > -0.09 and zeta > -0.3 respectively.

Nonphonon mechanism of superconductivity in compounds of transition metals

International Nuclear Information System (INIS)

Ivanov, V.A.; Zaitsev, R.O.

1989-01-01

The kinematical mechanism of superconductivity is applied to the Emery-Hirsch model for the CuO 2 and BiO 3 layers. A superconducting region due to strong kinematic interaction of p- and s, d-electrons are determined as a function of n p and n s,d -degrees of non-filling of 2p 6 ,6s 2 ,3d 10 shells of O 2 - ,Bi 3 + ,Cu + . The T c is calculated taking into account the spin flip relaxation time. Magnetostatic properties of a superconducting state in a weak magnetic field are investigated. Coefficients of the Ginzburg-Landau equation are calculated. The ground state energy of the Emery-Hirsch model is also calculated

One dimensionalization in the spin-1 Heisenberg model on the anisotropic triangular lattice

Science.gov (United States)

Gonzalez, M. G.; Ghioldi, E. A.; Gazza, C. J.; Manuel, L. O.; Trumper, A. E.

2017-11-01

We investigate the effect of dimensional crossover in the ground state of the antiferromagnetic spin-1 Heisenberg model on the anisotropic triangular lattice that interpolates between the regime of weakly coupled Haldane chains (J'≪J ) and the isotropic triangular lattice (J'=J ). We use the density-matrix renormalization group (DMRG) and Schwinger boson theory performed at the Gaussian correction level above the saddle-point solution. Our DMRG results show an abrupt transition between decoupled spin chains and the spirally ordered regime at (J'/J) c˜0.42 , signaled by the sudden closing of the spin gap. Coming from the magnetically ordered side, the computation of the spin stiffness within Schwinger boson theory predicts the instability of the spiral magnetic order toward a magnetically disordered phase with one-dimensional features at (J'/J) c˜0.43 . The agreement of these complementary methods, along with the strong difference found between the intra- and the interchain DMRG short spin-spin correlations for sufficiently large values of the interchain coupling, suggests that the interplay between the quantum fluctuations and the dimensional crossover effects gives rise to the one-dimensionalization phenomenon in this frustrated spin-1 Hamiltonian.

Peroxide values of Aglaia argentea Blume, A. silvestria (M. Roemer Merr., dan A. tomentosa Teijsm. & Binn.

Directory of Open Access Journals (Sweden)

PRAPTIWI

2006-07-01

Full Text Available The objectives of this research were to determine the chemical components and the peroxide values of three Aglaia species (A. argentea Blume, A. silvestria (M. Roemer Merr and A. tomentosa Teijsm & Binn. Phytochemical screening was done by Cuiley method, while peroxide values were determined by iodometri-titration on methanol, hexane, chloroform and ethyl acetate extracts. The result of phytochemical screening indicated that all of Aglaia species tested (three species contained sterol and triterpenoids, base alkaloid, reduction sugar, and anthrasenoid while other components present only in one or two species of Aglaia. Peroxide values of the tested extracts were higher than that of vitamin E (40.996 mili-equivalent/1000 g samples as a standard reductor, except the peroxide value of chloroform extract of A. tomentosa (41.078 milli-equivalent/ 1000 g sample. It can be concluded that A. tomentosa chloroform extract might had similar ability with vitamin E in preventing or delaying oxidation process. A. tomentosa chloroform extract acted as reductor.

Ground-state phases of the spin-1 J1-J2 Heisenberg antiferromagnet on the honeycomb lattice

Science.gov (United States)

Li, P. H. Y.; Bishop, R. F.

2016-06-01

We study the zero-temperature quantum phase diagram of a spin-1 Heisenberg antiferromagnet on the honeycomb lattice with both nearest-neighbor exchange coupling J1>0 and frustrating next-nearest-neighbor coupling J2≡κ J1>0 , using the coupled cluster method implemented to high orders of approximation, and based on model states with different forms of classical magnetic order. For each we calculate directly in the bulk thermodynamic limit both ground-state low-energy parameters (including the energy per spin, magnetic order parameter, spin stiffness coefficient, and zero-field uniform transverse magnetic susceptibility) and their generalized susceptibilities to various forms of valence-bond crystalline (VBC) order, as well as the energy gap to the lowest-lying spin-triplet excitation. In the range 0 κc 2=0.340 (5 ) . Two different paramagnetic phases are found to exist in the intermediate region. Over the range κc1<κ<κci=0.305 (5 ) we find a gapless phase with no discernible magnetic order, which is a strong candidate for being a quantum spin liquid, while over the range κci<κ <κc 2 we find a gapped phase, which is most likely a lattice nematic with staggered dimer VBC order that breaks the lattice rotational symmetry.

Mechanisms for spin supersolidity in S=(1/2) spin-dimer antiferromagnets

International Nuclear Information System (INIS)

Picon, J.-D.; Albuquerque, A. F.; Schmidt, K. P.; Laflorencie, N.; Troyer, M.; Mila, F.

2008-01-01

Using perturbative expansions and the contractor renormalization (CORE) algorithm, we obtain effective hard-core bosonic Hamiltonians describing the low-energy physics of S=1/2 spin-dimer antiferromagnets known to display supersolid phases under an applied magnetic field. The resulting effective models are investigated by means of mean-field analysis and quantum Monte Carlo simulations. A ''leapfrog mechanism,'' through means of which extra singlets delocalize in a checkerboard-solid environment via correlated hoppings, is unveiled that accounts for the supersolid behavior

Evidence for quark-hadron duality in the proton spin asymmetry A1

International Nuclear Information System (INIS)

Airapetian, A.; Akopov, N.; Akopov, Z.; Avakian, R.; Avetissian, A.; Avetissian, E.; Elbakian, G.; Gharibyan, V.; Marukyan, H.; Rostomyan, A.; Taroian, S.; Zohrabian, H.; Amarian, M.; Ammosov, V.V.; Gapienko, V.; Aschenauer, E.C.; Boettcher, H.; Ehrenfried, M.; Ellinghaus, F.; Jung, P.

2003-01-01

Spin-dependent lepton-nucleon scattering data have been used to investigate the validity of the concept of quark-hadron duality for the spin asymmetry A 1 . Longitudinally polarized positrons were scattered off a longitudinally polarized hydrogen target for values of Q 2 between 1.2 and 12 GeV 2 and values of W 2 between 1 and 4 GeV 2 . The average double-spin asymmetry in the nucleon resonance region is found to agree with that measured in deep-inelastic scattering at the same values of the Bjorken scaling variable x. This finding implies that the description of A 1 in terms of quark degrees of freedom is valid also in the nucleon resonance region for values of Q 2 above 1.6 GeV 2

Level crossing, spin structure factor and quantum phases of the frustrated spin-1/2 chain with first and second neighbor exchange.

Science.gov (United States)

Kumar, Manoranjan; Parvej, Aslam; Soos, Zoltán G

2015-08-12

The spin-1/2 chain with isotropic Heisenberg exchange J1, J2  >  0 between first and second neighbors is frustrated for either sign of J1. Its quantum phase diagram has critical points at fixed J1/J2 between gapless phases with nondegenerate ground state (GS) and quasi-long-range order (QLRO) and gapped phases with doubly degenerate GS and spin correlation functions of finite range. In finite chains, exact diagonalization (ED) estimates critical points as level crossing of excited states. GS spin correlations enter in the spin structure factor S(q) that diverges at wave vector qm in QLRO(q(m)) phases with periodicity 2π/q(m) but remains finite in gapped phases. S(q(m)) is evaluated using ED and density matrix renormalization group (DMRG) calculations. Level crossing and the magnitude of S(q(m)) are independent and complementary probes of quantum phases, based respectively on excited and ground states. Both indicate a gapless QLRO(π/2) phase between  -1.2  quantum critical points at small frustration J2 but disagree in the sector of weak exchange J1 between Heisenberg antiferromagnetic chains on sublattices of odd and even-numbered sites.

Higher-spin currents in the Gross-Neveu model at 1/n"2

International Nuclear Information System (INIS)

Manashov, A.N.

2016-10-01

We calculate the anomalous dimensions of higher-spin currents, both singlet and non-singlet, in the Gross - Neveu model at the 1/n"2 order. It was conjectured that in the critical regime this model is dual to a higher-spin gauge theory on AdS_4. The AdS/CFT correspondence predicts that the masses of higher-spin fields correspond to the scaling dimensions of the singlet currents in the Gross - Neveu model.

Novel spin dynamics in ferrimagnetic molecular chains from 1H NMR and μSR spin-lattice relaxation measurements

International Nuclear Information System (INIS)

Micotti, E.; Lascialfari, A.; Rigamonti, A.; Aldrovandi, S.; Caneschi, A.; Gatteschi, D.; Bogani, L.

2004-01-01

The spin dynamics in the helical chain Co(hfac) 2 NITPhOMe has been investigated by 1 H NMR and μSR relaxation. In the temperature range 15< T<60 K, the results are consistent with the relaxation of the homogeneous magnetization. For T≤15 K, NMR and μSR evidence a second spin relaxation mechanism, undetected by the magnetization measurements. From the analysis of these data, insights on this novel relaxation process are derived

Novel spin dynamics in ferrimagnetic molecular chains from 1H NMR and μSR spin-lattice relaxation measurements

Science.gov (United States)

Micotti, E.; Lascialfari, A.; Rigamonti, A.; Aldrovandi, S.; Caneschi, A.; Gatteschi, D.; Bogani, L.

2004-05-01

The spin dynamics in the helical chain Co(hfac) 2NITPhOMe has been investigated by 1H NMR and μSR relaxation. In the temperature range 15spin relaxation mechanism, undetected by the magnetization measurements. From the analysis of these data, insights on this novel relaxation process are derived.

Violation of local realism by a system with N spin-(1/2) particles

International Nuclear Information System (INIS)

Wu, Xiao-Hua; Zong, Hong-Shi

2003-01-01

Recently, it was found that Mermin's inequalities may not always be optimal for the refutation of a local realistic description [Phys. Rev. Lett. 88, 210402 (2002)]. To complete this work, we derive an inequality for the Greenberger-Horne-Zeilinger-type pure state for a system with N spin-(1/2) particles and the violation of the inequality can be shown for all the non product pure states. Mermin's inequality for a system of N spin-(1/2) particles and Gisin's theorem for a system of two spin-(1/2) particles are both included in our inequality

Field-controlled spin current in frustrated spin chains

Directory of Open Access Journals (Sweden)

A.K. Kolezhuk

2009-01-01

Full Text Available We study states with spontaneous spin current, emerging in frustrated antiferromagnetic spin-S chains subject to a strong external magnetic field. As a numerical tool, we use a non-Abelian symmetry realization of the density matrix renormalization group. The field dependence of the order parameter and the critical exponents are presented for zigzag chains with S=1/2, 1, 3/2, and 2.

Temperature dependence of the NMR spin-lattice relaxation rate for spin-1/2 chains

Science.gov (United States)

Coira, E.; Barmettler, P.; Giamarchi, T.; Kollath, C.

2016-10-01

We use recent developments in the framework of a time-dependent matrix product state method to compute the nuclear magnetic resonance relaxation rate 1 /T1 for spin-1/2 chains under magnetic field and for different Hamiltonians (XXX, XXZ, isotropically dimerized). We compute numerically the temperature dependence of the 1 /T1 . We consider both gapped and gapless phases, and also the proximity of quantum critical points. At temperatures much lower than the typical exchange energy scale, our results are in excellent agreement with analytical results, such as the ones derived from the Tomonaga-Luttinger liquid (TLL) theory and bosonization, which are valid in this regime. We also cover the regime for which the temperature T is comparable to the exchange coupling. In this case analytical theories are not appropriate, but this regime is relevant for various new compounds with exchange couplings in the range of tens of Kelvin. For the gapped phases, either the fully polarized phase for spin chains or the low-magnetic-field phase for the dimerized systems, we find an exponential decrease in Δ /(kBT ) of the relaxation time and can compute the gap Δ . Close to the quantum critical point our results are in good agreement with the scaling behavior based on the existence of free excitations.

CONSTRAINING THE SPIN-DOWN OF THE NEARBY ISOLATED NEUTRON STAR RX J0806.4-4123, AND IMPLICATIONS FOR THE POPULATION OF NEARBY NEUTRON STARS

International Nuclear Information System (INIS)

Kaplan, D. L.; Van Kerkwijk, M. H.

2009-01-01

The nearby isolated neutron stars (INSs) are a group of seven relatively slowly rotating neutron stars that show thermal X-ray spectra, most with broad absorption features. They are interesting both because they may allow one to determine fundamental neutron-star properties by modeling their spectra, and because they appear to be a large fraction of the overall neutron-star population. Here, we describe a series of XMM -Newton observations of the nearby INS RX J0806.4-4123, taken as part of larger program of timing studies. From these, we limit the spin-down rate to ν-dot=(-4.3±2.3)x10 -16 Hz s -1 . This constrains the dipole magnetic field to be 13 G at 2σ, significantly less than the field of ∼10 14 G implied by simple models for the X-ray absorption found at 0.45 keV. We confirm that the spectrum is thermal and stable (to within a few percent), but find that the 0.45 keV absorption feature is broader and more complex than previously thought. Considering the population of INSs, we find that magnetic field decay from an initial field of ∼ 14 G accounts most naturally for their timing and spectral properties, both qualitatively and in the context of the models for field decay of Pons and collaborators.

Impact of mass generation for spin-1 mediator simplified models

International Nuclear Information System (INIS)

Bell, Nicole F.; Cai, Yi; Leane, Rebecca K.

2017-01-01

In the simplified dark matter models commonly studied, the mass generation mechanism for the dark fields is not typically specified. We demonstrate that the dark matter interaction types, and hence the annihilation processes relevant for relic density and indirect detection, are strongly dictated by the mass generation mechanism chosen for the dark sector particles, and the requirement of gauge invariance. We focus on the class of models in which fermionic dark matter couples to a spin-1 vector or axial-vector mediator. However, in order to generate dark sector mass terms, it is necessary in most cases to introduce a dark Higgs field and thus a spin-0 scalar mediator will also be present. In the case that all the dark sector fields gain masses via coupling to a single dark sector Higgs field, it is mandatory that the axial-vector coupling of the spin-1 mediator to the dark matter is non-zero; the vector coupling may also be present depending on the charge assignments. For all other mass generation options, only pure vector couplings between the spin-1 mediator and the dark matter are allowed. If these coupling restrictions are not obeyed, unphysical results may be obtained such as a violation of unitarity at high energies. These two-mediator scenarios lead to important phenomenology that does not arise in single mediator models. We survey two-mediator dark matter models which contain both vector and scalar mediators, and explore their relic density and indirect detection phenomenology.

Organic Additives Improves the in Vitro Growth of Native Orchid Vanda helvola Blume

Directory of Open Access Journals (Sweden)

Devina DAVID

2015-06-01

Full Text Available In vitro seed germination has been proven to be the most efficient technique to propagate orchid. The application of this aseptic technique has contributed to conservation of many endangered orchid species. In this study, undehisced capsules of Vanda helvola Blume were collected from Orchid Conservation Centre in Lagud Sebrang Agriculture Park, after 120 days from hand pollination and aseptically cultured on three types of basal media such as Murashige and Skoog (MS, Knudson C (KC and Vacin and Went (VW. After 90 days of culture, 66.40 ± 4.14% of seeds successfully germinated on KC medium. The effect of organic additives such as tomato juice, coconut water, peptone and yeast extract at different level of concentrations in KC basal medium were also tested on seed germination and seedling development of this native orchid. After 90 days of culture, over 90% of seeds were tremendously germinated on KC medium supplemented with 10% or 15% (v/v of tomato juice. The incorporation of peptone at 0.1% (w/v in KC basal media promoted rapid development of protocorm to seedling. Seedlings on this treatment produced an average of three leaves and two roots after 90 days of culture and were successfully acclimatized.

Investigation of Spinning and Tumbling Characteristics of a 1/20-Scale Model of the Consolidated Vultee XFY-1 Airplane in the Free-Spinning Tunnel, TED No. NACA DE 370

Science.gov (United States)

Lee, Henry A.

1952-01-01

An investigation has been conducted in the Langley 20-foot free-spinning tunnel on a l/20-scale model of the Consolidated Vultee XFY-1 airplane with a windmilling propeller simulated to determine the effects of control setting and movements upon the erect spin and recovery characteristics for a range of airplane-loading conditions. The effects on the model's spin-recovery characteristics of removing the lower vertical tail, removing the gun pods, and fixing the rudders at neutral were also investigated briefly. The investigation included determination of the size parachute required for emergency recovery from demonstration spins. The tumbling tendencies of the model were also investigated. Brief static force tests were made to determine the aerodynamic characteristics in pitch at high angles of attack. The investigation indicated that the spin and recovery characteristics of the airplane with propeller windmilling will be satisfactory for all loading conditions if recovery is attempted by full rudder reversal accompanied by simultaneous movement of the stick laterally to full with the spin (stick right in a right spin) and longitudinally to neutral. Inverted spins should be satisfactorily terminated by fully reversing the rudder followed immediately by moving the stick laterally towards the forward rudder pedal and longitudinally to neutral. Removal of the gun pods or fixing the rudders at neutral will not adversely affect the airplane's spin-recovery characteristics, but removal of the lower vertical tail will result in unsatisfactory spin-recovery characteristics. The model-test results showed that a 13.3-foot wing-tip conventional parachute (drag coefficient approximately 0.7) should be effective as an emergency spin-recovery device during demonstration spins of the airplane. It was indicated that the airplane should not tumble and that no unusual longitudinal-trim characteristics should be obtained for the center-of-gravity positions investigated.

Muon spin relaxation measurements of spin-correlation decay in spin-glass AgMn

Energy Technology Data Exchange (ETDEWEB)

Heffner, R.H.; Cooke, D.W.; Leon, M.; Schillaci, M.E. (Los Alamos National Lab., NM (USA)); MacLaughlin, D.E.; Gupta, L.C. (California Univ., Riverside (USA))

1984-01-01

The field (H) dependence of the muon longitudinal spin-lattice relaxation rate well below the spin glass temperature in AgMn is found to obey an algebraic form given by (H)sup(..gamma..-1), with ..gamma.. = 0.54 +- 0.05. This suggests that Mn spin correlations decay with time as tsup(-..gamma..), in agreement with mean field theories of spin-glass dynamics which yield ..gamma..

Current-State Constrained Filter Bank for Wald Testing of Spacecraft Conjunctions

Science.gov (United States)

Carpenter, J. Russell; Markley, F. Landis

2012-01-01

We propose a filter bank consisting of an ordinary current-state extended Kalman filter, and two similar but constrained filters: one is constrained by a null hypothesis that the miss distance between two conjuncting spacecraft is inside their combined hard body radius at the predicted time of closest approach, and one is constrained by an alternative complementary hypothesis. The unconstrained filter is the basis of an initial screening for close approaches of interest. Once the initial screening detects a possibly risky conjunction, the unconstrained filter also governs measurement editing for all three filters, and predicts the time of closest approach. The constrained filters operate only when conjunctions of interest occur. The computed likelihoods of the innovations of the two constrained filters form a ratio for a Wald sequential probability ratio test. The Wald test guides risk mitigation maneuver decisions based on explicit false alarm and missed detection criteria. Since only current-state Kalman filtering is required to compute the innovations for the likelihood ratio, the present approach does not require the mapping of probability density forward to the time of closest approach. Instead, the hard-body constraint manifold is mapped to the filter update time by applying a sigma-point transformation to a projection function. Although many projectors are available, we choose one based on Lambert-style differential correction of the current-state velocity. We have tested our method using a scenario based on the Magnetospheric Multi-Scale mission, scheduled for launch in late 2014. This mission involves formation flight in highly elliptical orbits of four spinning spacecraft equipped with antennas extending 120 meters tip-to-tip. Eccentricities range from 0.82 to 0.91, and close approaches generally occur in the vicinity of perigee, where rapid changes in geometry may occur. Testing the method using two 12,000-case Monte Carlo simulations, we found the

Spin Tests of 1/20-Scale Models of the Chance Vought Revised XF6U-1 and F6U-1 Airplanes, TED No. NACA 2390

Science.gov (United States)

Klinar, Walter J.; Berman, Theodore

1948-01-01

An investigation has been conducted in the Langley 20-foot free-spinning tunnel on the 1/20-scale model of the Chance Vought XF6U-1 airplane altered to represent the XF6U-1 airplane as it will be spin-tested in flight, and also altered to represent the F6U-1 airplane as it will be produced for service use. Spin tests were made to determine the effects of control settings and movements at the normal loading. The results show that the spins obtained on the revised XF6U-1 airplane will be oscillatory in roll and yaw and that recoveries by rudder reversal will be rapid. Model test results indicate that the F6U-1 airplane will probably not spin. Inasmuch as the results of this investigation show that the new designs are as good as or better than the original XF6U-1 design in regard to spin recovery, it is felt that the conclusions and recommendations reached for the original design can be applied to the new designs for all loading conditions.

Spin texture and magnetoroton excitations at nu=1/3.

Science.gov (United States)

Groshaus, Javier G; Dujovne, Irene; Gallais, Yann; Hirjibehedin, Cyrus F; Pinczuk, Aron; Tan, Yan-Wen; Stormer, Horst; Dennis, Brian S; Pfeiffer, Loren N; West, Ken W

2008-02-01

Neutral spin texture (ST) excitations at nu=1/3 are directly observed for the first time by resonant inelastic light scattering. They are determined to involve two simultaneous spin flips. At low magnetic fields, the ST energy is below that of the magnetoroton minimum. With increasing in-plane magnetic field these mode energies cross at a critical ratio of the Zeeman and Coulomb energies of eta(c)=0.020+/-0.001. Surprisingly, the intensity of the ST mode grows with temperature in the range in which the magnetoroton modes collapse. The temperature dependence is interpreted in terms of a competition between coexisting phases supporting different excitations. We consider the role of the ST excitations in activated transport at nu=1/3.

Empowerment through education and science: three intersecting strands in the career of Griffith Edwards.

Science.gov (United States)

Crome, Ilana

2015-07-01

This paper describes three important strands in the career of Griffith Edwards that define him as a leader and an innovator. Believing that education and science were critical for the development of addiction as a profession and as a field of inquiry, his approach was multi-faceted: educating all doctors to appreciate the fundamental issues in addiction; training psychiatrists in the complexity of 'dual diagnosis' and specific specialist intervention; and teaching that addiction could be a chronic condition which required care management over the life course. These three inter-related areas are directly related to the need for a range of practitioners to have an understanding of addiction so that patients can be properly managed. The greater our understanding of the nature of addiction behaviour, the more likely the potential to optimize treatment and train practitioners from different professional disciplines. © 2015 Society for the Study of Addiction.

Prima facie evidence against spin-two Higgs impostors

Science.gov (United States)

Ellis, John; Sanz, Verónica; You, Tevong

2013-10-01

The new particle X recently discovered by the ATLAS and CMS Collaborations is widely expected to have spin zero, but this remains to be determined. The leading alternative is that X has spin two, presumably with graviton-like couplings. We show that measurements of the X particle to pairs of vector bosons constrain such scenarios. In particular, a graviton-like Higgs impostor in scenarios with a warped extra dimension of AdS type is prima facie excluded, principally because they predict too small a ratio between the X couplings to WW and ZZ, compared with that to photons. The data also disfavour universal couplings to pairs of photons and gluons, which would be predicted in a large class of graviton-like models.

Prima Facie Evidence against Spin-Two Higgs Impostors

CERN Document Server

Ellis, John; You, Tevong

2013-01-01

The new particle X recently discovered by the ATLAS and CMS Collaborations is widely expected to have spin zero, but this remains to be determined. The leading alternative is that X has spin two, presumably with graviton-like couplings. We show that measurements of the X particle to pairs of vector bosons constrain such scenarios. In particular, a graviton-like Higgs impostor in scenarios with a warped extra dimension of AdS type is prima facie excluded, principally because they predict too small a ratio between the X couplings to WW and ZZ, compared with that to photons. The data also disfavour universal couplings to pairs of photons and gluons, which would be predicted in a large class of graviton-like models.

Prima facie evidence against spin-two Higgs impostors

International Nuclear Information System (INIS)

Ellis, John; Sanz, Verónica; You, Tevong

2013-01-01

The new particle X recently discovered by the ATLAS and CMS Collaborations is widely expected to have spin zero, but this remains to be determined. The leading alternative is that X has spin two, presumably with graviton-like couplings. We show that measurements of the X particle to pairs of vector bosons constrain such scenarios. In particular, a graviton-like Higgs impostor in scenarios with a warped extra dimension of AdS type is prima facie excluded, principally because they predict too small a ratio between the X couplings to WW and ZZ, compared with that to photons. The data also disfavour universal couplings to pairs of photons and gluons, which would be predicted in a large class of graviton-like models

Prima facie evidence against spin-two Higgs impostors

Energy Technology Data Exchange (ETDEWEB)

Ellis, John [Theoretical Particle Physics and Cosmology Group, Physics Department, King' s College London, London WC2R 2LS (United Kingdom); TH Division, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Sanz, Verónica, E-mail: vsanz@yorku.ca [TH Division, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Department of Physics and Astronomy, York University, Toronto, ON, M3J 1P3 (Canada); You, Tevong [Theoretical Particle Physics and Cosmology Group, Physics Department, King' s College London, London WC2R 2LS (United Kingdom)

2013-10-07

The new particle X recently discovered by the ATLAS and CMS Collaborations is widely expected to have spin zero, but this remains to be determined. The leading alternative is that X has spin two, presumably with graviton-like couplings. We show that measurements of the X particle to pairs of vector bosons constrain such scenarios. In particular, a graviton-like Higgs impostor in scenarios with a warped extra dimension of AdS type is prima facie excluded, principally because they predict too small a ratio between the X couplings to WW and ZZ, compared with that to photons. The data also disfavour universal couplings to pairs of photons and gluons, which would be predicted in a large class of graviton-like models.

An S=1/2 impurity spin in the antiferromagnetic S=1 bond-alternating chain

Energy Technology Data Exchange (ETDEWEB)

Ogawa, Nobuyuki [Gifu National College of Technology, Dept. of Fundamental Science, Gifu (Japan); Hikihara, Toshiya [National Inst. for Materials Science, Computational Material Research Group, Tsukuba, Ibaraki (Japan); Kaburagi, Makoto [Kobe Univ., Faculty of Cross-Cultural Studies, Kobe, Hyogo (Japan); Tonegawa, Takashi [Fukui Univ. of Technology, Dept. of Mechanical Engineering, Fukui (Japan)

2002-06-01

We explore low-lying excited states as well as the ground state of the antiferromagnetic S=1 bond-alternating chain with an S=1/2 impurity spin. For the case where the ground-state phase of the host system is the Haldane phase, we review a numerical analysis of the electron-spin-resonance experimental results on the NENP: Cu{sup 2+} system. For the case where the ground-state phase of the host system is the dimer phase, on the other hand, we calculate, using the exact-diagonalization method, the dependences of the energy differences between the ground and low-lying excited states upon both the impurity-host exchange constant and the single-ion-type anisotropy constant, and also calculate, using the density-matrix renormalization-group method, the external-magnetic-field dependence of the impurity-spin magnetization in the ground state. In these calculations, we keep the NTENP: Cu{sup 2+} system in mind to choose the value of the bond-alternation parameter. We find that a few low-lying excited states which are expected from the valence-bond-solid picture appear as the impurity states in the energy gap between the singlet ground and triplet first-excited states (the dimer gap). Furthermore, for certain values of the above constants, we find that the impurity-spin magnetization shows a clear jump at a magnetic field which is in the dimer-gap region or in the magnetization-plateau region of the host system, and also that the impurity-spin magnetization has a magnetic-field region where it decreases as a function of the magnetic field. (author)

Spin-1/2 Heisenberg antiferromagnet on the pyrochlore lattice: An exact diagonalization study

Science.gov (United States)

Chandra, V. Ravi; Sahoo, Jyotisman

2018-04-01

We present exact diagonalization calculations for the spin-1/2 nearest-neighbor antiferromagnet on the pyrochlore lattice. We study a section of the lattice in the [111] direction and analyze the Hamiltonian of the breathing pyrochlore system with two coupling constants J1 and J2 for tetrahedra of different orientations and investigate the evolution of the system from the limit of disconnected tetrahedra (J2=0 ) to a correlated state at J1=J2 . We evaluate the low-energy spectrum, two and four spin correlations, and spin chirality correlations for a system size of up to 36 sites. The model shows a fast decay of spin correlations and we confirm the presence of several singlet excitations below the lowest magnetic excitation. We find chirality correlations near J1=J2 to be small at the length scales available at this system size. Evaluation of dimer-dimer correlations and analysis of the nature of the entanglement of the tetrahedral unit shows that the triplet sector of the tetrahedron contributes significantly to the ground-state entanglement at J1=J2 .

Muon spin relaxation measurements of spin-correlation decay in spin-glass AgMn

International Nuclear Information System (INIS)

Heffner, R.H.; Cooke, D.W.; Leon, M.; Schillaci, M.E.; MacLaughlin, D.E.; Gupta, L.C.

1984-01-01

The field (H) dependence of the muon longitudinal spin-lattice relaxation rate well below the spin glass temperature in AgMn is found to obey an algebraic form given by (H)sup(γ-1), with γ = 0.54 +- 0.05. This suggests that Mn spin correlations decay with time as tsup(-γ), in agreement with mean field theories of spin-glass dynamics which yield γ < approx. 0.5. Near the glass temperature the agreement between the data and theory is not as good. (Auth.)

Quasipotential approach to the Coulomb bound state problem for spin-0 and spin-/sup 1///sub 2/ particles

CERN Document Server

Rizov, V A; Todorov, I T

1975-01-01

A recently proposed local quasipotential equation is reviewed and applied to the electromagnetic interaction of a spin-0 and a spin-/sup 1///sub 2/ particle. The Dirac particle is treated in a covariant two- component formalism in the neighbourhood of the mass shell. The fine structure of the bound state energy levels and the main part of the Lamb shift (of order alpha /sup 5/In(1/ alpha ) are evaluated with full account of relativistic recoil effects (without using any inverse mass expansion). Possible relevance of the techniques developed in this paper to fine structure calculations for meso-atomic systems is pointed out. (14 refs).

Continuous wave protocol for simultaneous polarization and optical detection of P1-center electron spin resonance

Science.gov (United States)

Kamp, E. J.; Carvajal, B.; Samarth, N.

2018-01-01

The ready optical detection and manipulation of bright nitrogen vacancy center spins in diamond plays a key role in contemporary quantum information science and quantum metrology. Other optically dark defects such as substitutional nitrogen atoms (`P1 centers') could also become potentially useful in this context if they could be as easily optically detected and manipulated. We develop a relatively straightforward continuous wave protocol that takes advantage of the dipolar coupling between nitrogen vacancy and P1 centers in type 1b diamond to detect and polarize the dark P1 spins. By combining mutual spin flip transitions with radio frequency driving, we demonstrate the simultaneous optical polarization and detection of the electron spin resonance of the P1 center. This technique should be applicable to detecting and manipulating a broad range of dark spin populations that couple to the nitrogen vacancy center via dipolar fields, allowing for quantum metrology using these spin populations.

Topological-Sector Fluctuations and Curie-Law Crossover in Spin Ice

Directory of Open Access Journals (Sweden)

L. D. C. Jaubert

2013-02-01

Full Text Available At low temperatures, a spin ice enters a Coulomb phase—a state with algebraic correlations and topologically constrained spin configurations. We show how analytical and numerical approaches for model spin-ice systems reveal a crossover between two Curie laws. One of these laws characterizes the high-temperature paramagnetic regime, while the other, which we call the “spin-liquid Curie law,” characterizes the low-temperature Coulomb-phase regime, which provides implicit evidence that the topological sector fluctuates. We compare our theory with experiment for Ho_{2}Ti_{2}O_{7}, where this process leads to a nonstandard temperature evolution of the bulk susceptibility and the wave-vector-dependent magnetic susceptibility, as measured by neutron scattering. Theory and experiment agree for bulk quantities and at large scattering wave vectors, but differences at small wave vectors indicate that the classical spin-ice states are not equally populated at low temperatures. More generally, the crossover appears to be a generic property of the emergent gauge field for a classical spin liquid, and it sheds light on the experimental difficulty of measuring a precise Curie-Weiss temperature in frustrated materials. The susceptibility at finite wave vectors is shown to be a local probe of fluctuations among topological sectors on varying length scales.

Faddeev-Senjanovic quantization of SU(n) N=2 supersymmetric gauge field system with a non-Abelian Chern-Simons topological term and its fractional spin

International Nuclear Information System (INIS)

Huang Yongchang; Huo Qiuhong

2008-01-01

Using Faddeev-Senjanovic path integral quantization for constrained Hamilton system, we quantize SU(n) N=2 supersymmetric gauge field system with non-Abelian Chern-Simons topological term in 2+1 dimensions. We use consistency of Coulomb gauge condition to naturally deduce a new gauge condition. Furthermore, we obtain the generating functional of Green function in phase space, deduce the angular momentum based on the global canonical Noether theorem at quantum level, obtain the fractional spin of this supersymmetric system, and show that the total angular momentum is the sum of the orbital angular momentum and spin angular momentum of the non-Abelian gauge field. Finally, we obtain the anomalous fractional spin and discover that the fractional spin has the contributions of both the group superscript components and A 0 s (x) charge

First evidence for spin-flip M1 strength in 40Ar

International Nuclear Information System (INIS)

Li, T.C.; Rainovski, G.; Pietralla, N.; Ahn, T.; Costin, A.; Tonchev, A.P.; Ahmed, M.W.; Blackston, M.A.; Parpottas, Y.; Perdue, B.A.; Tornow, W.; Weller, H.R.; Angell, C.; Keeter, K.J.; Li, J.; Mikhailov, S.; Wu, Y.K.; Lisetskiy, A.

2006-01-01

The 40 Ar(γ→,γ ' ) photon scattering reaction was used to search for spin-flip M1 strength in 40 Ar. The nearly monochromatic, linearly polarized photon beam of HIγS, in an energy region from 7.7 to 11 MeV, was employed in this study. 28 dipole excitations were observed. The azimuthal intensity asymmetry indicated that all of these states were E1 except for the state at E x =9.757 MeV. Shell-model calculations were used to interpret this state as one fragment of the spin-flip M1 strength in 40 Ar

Muon spin-relaxation measurements of spin-correlation decay in spin-glass AgMn

International Nuclear Information System (INIS)

Heffner, R.H.; Cooke, D.W.; Leon, M.; Schillaci, M.E.; MacLaughlin, D.E.; Gupta, L.C.

1983-01-01

The field (H) dependence of the muon longitudinal spin-lattice relaxation rate well below the spin-glass temperature in AgMn is found to obey an algebraic form given by (H)/sup nu-1/, with nu = 0.54 +- 0.05. This suggests that Mn spin correlations decay with time as t - /sup nu/, in agreement with mean field theories of spin-glass dynamics which yield nu less than or equal to 0.5. Near the glass temperature the agreement between the data and theory is not as good

Irreversibility and self-organization in spin glasses. 1. Origin of irreversibility in spin glasses

International Nuclear Information System (INIS)

Kovrov, V.P.; Kurbatov, A.M.

1989-05-01

The origin of irreversibility in spin glasses is found out on the basis of the analytical study of the well-known TAP equations. Connection between irreversible jumpwise transitions and a positive feedback in spin glasses is discussed. (author). 7 refs, 4 figs

Hardy's argument and successive spin-s measurements

International Nuclear Information System (INIS)

Ahanj, Ali

2010-01-01

We consider a hidden-variable theoretic description of successive measurements of noncommuting spin observables on an input spin-s state. In this scenario, the hidden-variable theory leads to a Hardy-type argument that quantum predictions violate it. We show that the maximum probability of success of Hardy's argument in quantum theory is ((1/2)) 4s , which is more than in the spatial case.

Tunable Quantum Spin Liquidity in the 1 /6 th-Filled Breathing Kagome Lattice

Science.gov (United States)

Akbari-Sharbaf, A.; Sinclair, R.; Verrier, A.; Ziat, D.; Zhou, H. D.; Sun, X. F.; Quilliam, J. A.

2018-06-01

We present measurements on a series of materials, Li2 In1 -xScx Mo3 O8 , that can be described as a 1 /6 th-filled breathing kagome lattice. Substituting Sc for In generates chemical pressure which alters the breathing parameter nonmonotonically. Muon spin rotation experiments show that this chemical pressure tunes the system from antiferromagnetic long range order to a quantum spin liquid phase. A strong correlation with the breathing parameter implies that it is the dominant parameter controlling the level of magnetic frustration, with increased kagome symmetry generating the quantum spin liquid phase. Magnetic susceptibility measurements suggest that this is related to distinct types of charge order induced by changes in lattice symmetry, in line with the theory of Chen et al. [Phys. Rev. B 93, 245134 (2016), 10.1103/PhysRevB.93.245134]. The specific heat for samples at intermediate Sc concentration, which have the minimum breathing parameter, show consistency with the predicted U (1 ) quantum spin liquid.

Microscopic theory of the nearest-neighbor valence bond sector of the spin-1/2 kagome antiferromagnet

Science.gov (United States)

Ralko, Arnaud; Mila, Frédéric; Rousochatzakis, Ioannis

2018-03-01

The spin-1/2 Heisenberg model on the kagome lattice, which is closely realized in layered Mott insulators such as ZnCu3(OH) 6Cl2 , is one of the oldest and most enigmatic spin-1/2 lattice models. While the numerical evidence has accumulated in favor of a quantum spin liquid, the debate is still open as to whether it is a Z2 spin liquid with very short-range correlations (some kind of resonating valence bond spin liquid), or an algebraic spin liquid with power-law correlations. To address this issue, we have pushed the program started by Rokhsar and Kivelson in their derivation of the effective quantum dimer model description of Heisenberg models to unprecedented accuracy for the spin-1/2 kagome, by including all the most important virtual singlet contributions on top of the orthogonalization of the nearest-neighbor valence bond singlet basis. Quite remarkably, the resulting picture is a competition between a Z2 spin liquid and a diamond valence bond crystal with a 12-site unit cell, as in the density-matrix renormalization group simulations of Yan et al. Furthermore, we found that, on cylinders of finite diameter d , there is a transition between the Z2 spin liquid at small d and the diamond valence bond crystal at large d , the prediction of the present microscopic description for the two-dimensional lattice. These results show that, if the ground state of the spin-1/2 kagome antiferromagnet can be described by nearest-neighbor singlet dimers, it is a diamond valence bond crystal, and, a contrario, that, if the system is a quantum spin liquid, it has to involve long-range singlets, consistent with the algebraic spin liquid scenario.

The transverse spin-1 Ising model with random interactions

Energy Technology Data Exchange (ETDEWEB)

Bouziane, Touria [Department of Physics, Faculty of Sciences, University of Moulay Ismail, B.P. 11201 Meknes (Morocco)], E-mail: touria582004@yahoo.fr; Saber, Mohammed [Department of Physics, Faculty of Sciences, University of Moulay Ismail, B.P. 11201 Meknes (Morocco); Dpto. Fisica Aplicada I, EUPDS (EUPDS), Plaza Europa, 1, San Sebastian 20018 (Spain)

2009-01-15

The phase diagrams of the transverse spin-1 Ising model with random interactions are investigated using a new technique in the effective field theory that employs a probability distribution within the framework of the single-site cluster theory based on the use of exact Ising spin identities. A model is adopted in which the nearest-neighbor exchange couplings are independent random variables distributed according to the law P(J{sub ij})=p{delta}(J{sub ij}-J)+(1-p){delta}(J{sub ij}-{alpha}J). General formulae, applicable to lattices with coordination number N, are given. Numerical results are presented for a simple cubic lattice. The possible reentrant phenomenon displayed by the system due to the competitive effects between exchange interactions occurs for the appropriate range of the parameter {alpha}.

arXiv Longitudinal double-spin asymmetry $A_1^{\\rm p}$ and spin-dependent structure function $g_1^{\\rm p}$ of the proton at small values of $x$ and $Q^2$

CERN Document Server

Aghasyan, M.; The COMPASS collaboration; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anfimov, N.V.; Anosov, V.; Antoshkin, A.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C.D.R.; Badełek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E.R.; Birsa, R.; Bodlak, M.; Bordalo, P.; Bradamante, F.; Bressan, A.; Büchele, M.; Burtsev, V.E.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Choi, I.; Chumakov, A.G.; Chung, S.-U.; Cicuttin, A.; Crespo, M.L.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Dhara, L.; Donskov, S.V.; Doshita, N.; Dreisbach, Ch.; Dünnweber, W.; Dusaev, R.R.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Faessler, M.; Ferrero, A.; Finger, M.; jr.,M.Finger; Fischer, H.; Franco, C.; du Fresne von Hohenesche, N.; Friedrich, J.M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Giarra, J.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grasso, A.; Gridin, A.; Grosse Perdekamp, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Hahne, D.; Hamar, G.; von Harrach, D.; Heinsius, F.H.; Heitz, R.; Herrmann, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.-Y.; Huber, S.; Ishimoto, S.; Ivanov, A.; Iwata, T.; Jary, V.; Joosten, R.; Jörg, P.; Kabuß, E.; Kerbizi, A.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.M.; Kral, Z.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z.V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Kuznetsov, I.I.; Kveton, A.; Lednev, A.A.; Levchenko, E.A.; Levillain, M.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Longo, R.; Lyubovitskij, V.E.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.K.; Mamon, S.A.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.V.; Meyer, M.; Meyer, W.; Mikhailov, Yu.V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Moretti, A.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nový, J.; Nowak, W.-D.; Nukazuka, G.; Nunes, A.S.; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Pešková, M.; Peshekhonov, D.V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rogacheva, N.S.; Ryabchikov, D.I.; Rybnikov, A.; Rychter, A.; Salac, R.; Samoylenko, V.D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I.A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schönning, K.; Seder, E.; Selyunin, A.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolik, J.; Srnka, A.; Steffen, D.; Stolarski, M.; Subrt, O.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Tasevsky, M.; Tessaro, S.; Tessarotto, F.; Thiel, A.; Tomsa, J.; Tosello, F.; Tskhay, V.; Uhl, S.; Vasilishin, B.I.; Vauth, A.; Veloso, J.; Vidon, A.; Virius, M.; Wallner, S.; Weisrock, T.; Wilfert, M.; ter Wolbeek, J.; Zaremba, K.; Zavada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.

2018-06-10

We present a precise measurement of the proton longitudinal double-spin asymmetry A1p and the proton spin-dependent structure function g1p at photon virtualities 0.006(GeV/c)21(GeV/c)2 in the Bjorken x range of 4×10−51p and g1p are found to be positive. It is for the first time that spin effects are found at such low values of x .

Nonequilibrium dynamics of a mixed spin-1/2 and spin-3/2 Ising ferrimagnetic system with a time dependent oscillating magnetic field source

Energy Technology Data Exchange (ETDEWEB)

Vatansever, Erol [Dokuz Eylül University, Graduate School of Natural and Applied Sciences, TR-35160 Izmir (Turkey); Polat, Hamza, E-mail: hamza.polat@deu.edu.tr [Department of Physics, Dokuz Eylül University, TR-35160 Izmir (Turkey)

2015-10-15

Nonequilibrium phase transition properties of a mixed Ising ferrimagnetic model consisting of spin-1/2 and spin-3/2 on a square lattice under the existence of a time dependent oscillating magnetic field have been investigated by making use of Monte Carlo simulations with a single-spin flip Metropolis algorithm. A complete picture of dynamic phase boundary and magnetization profiles have been illustrated and the conditions of a dynamic compensation behavior have been discussed in detail. According to our simulation results, the considered system does not point out a dynamic compensation behavior, when it only includes the nearest-neighbor interaction, single-ion anisotropy and an oscillating magnetic field source. As the next-nearest-neighbor interaction between the spins-1/2 takes into account and exceeds a characteristic value which sensitively depends upon values of single-ion anisotropy and only of amplitude of external magnetic field, a dynamic compensation behavior occurs in the system. Finally, it is reported that it has not been found any evidence of dynamically first-order phase transition between dynamically ordered and disordered phases, which conflicts with the recently published molecular field investigation, for a wide range of selected system parameters. - Highlights: • Spin-1/2 and spin-3/2 Ising ferrimagnetic model is examined. • The system is exposed to time-dependent magnetic field. • Kinetic Monte Carlo simulation technique is used. • Any evidence of first-order phase transition has not been found.

Spin-photon interface and spin-controlled photon switching in a nanobeam waveguide

DEFF Research Database (Denmark)

Javadi, Alisa; Ding, Dapeng; Appel, Martin Hayhurst

2018-01-01

Access to the electron spin is at the heart of many protocols for integrated and distributed quantum-information processing [1-4]. For instance, interfacing the spin-state of an electron and a photon can be utilized to perform quantum gates between photons [2,5] or to entangle remote spin states [6......-9]. Ultimately, a quantum network of entangled spins constitutes a new paradigm in quantum optics [1]. Towards this goal, an integrated spin-photon interface would be a major leap forward. Here we demonstrate an efficient and optically programmable interface between the spin of an electron in a quantum dot...... and photons in a nanophotonic waveguide. The spin can be deterministically prepared with a fidelity of 96\\%. Subsequently the system is used to implement a "single-spin photonic switch", where the spin state of the electron directs the flow of photons through the waveguide. The spin-photon interface may...

Muon spin relaxation in ferromagnets. Pt. 1

International Nuclear Information System (INIS)

Lovesey, S.W.; Karlsson, E.B.

1991-04-01

Expressions for the dipolar and hyperfine contributions to the relaxation rate of muons implanted in a ferromagnet are presented and analysed using the Heisenberg model of spin-waves including dipolar and Zeeman energies. Calculations for EuO indicate that relaxation is likely to be dominated by the hyperfine mechanism, even if the ratio of the hyperfine and dipolar coupling constants is small. The hyperfine mechanism is sensitive to the dipolar energy of the atomic spins, whereas the dipolar mechanisms depend essentially on the exchange energy. For both mechanisms there is an almost quadratic dependence on temperature, throughout much of the ordered magnetic phase, which reflects two-spin-wave difference events from the Raman-type relaxation processes. (author)

Nuclear spin-lattice relaxation in nitroxide spin-label EPR.

Science.gov (United States)

Marsh, Derek

2016-11-01

Nuclear relaxation is a sensitive monitor of rotational dynamics in spin-label EPR. It also contributes competing saturation transfer pathways in T 1 -exchange spectroscopy, and the determination of paramagnetic relaxation enhancement in site-directed spin labelling. A survey shows that the definition of nitrogen nuclear relaxation rate W n commonly used in the CW-EPR literature for 14 N-nitroxyl spin labels is inconsistent with that currently adopted in time-resolved EPR measurements of saturation recovery. Redefinition of the normalised 14 N spin-lattice relaxation rate, b=W n /(2W e ), preserves the expressions used for CW-EPR, whilst rendering them consistent with expressions for saturation recovery rates in pulsed EPR. Furthermore, values routinely quoted for nuclear relaxation times that are deduced from EPR spectral diffusion rates in 14 N-nitroxyl spin labels do not accord with conventional analysis of spin-lattice relaxation in this three-level system. Expressions for CW-saturation EPR with the revised definitions are summarised. Data on nitrogen nuclear spin-lattice relaxation times are compiled according to the three-level scheme for 14 N-relaxation: T 1 n =1/W n . Results are compared and contrasted with those for the two-level 15 N-nitroxide system. Copyright © 2016 Elsevier Inc. All rights reserved.

S1 constrains S4 in the voltage sensor domain of Kv7.1 K+ channels.

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Yoni Haitin

Full Text Available Voltage-gated K(+ channels comprise a central pore enclosed by four voltage-sensing domains (VSDs. While movement of the S4 helix is known to couple to channel gate opening and closing, the nature of S4 motion is unclear. Here, we substituted S4 residues of Kv7.1 channels by cysteine and recorded whole-cell mutant channel currents in Xenopus oocytes using the two-electrode voltage-clamp technique. In the closed state, disulfide and metal bridges constrain residue S225 (S4 nearby C136 (S1 within the same VSD. In the open state, two neighboring I227 (S4 are constrained at proximity while residue R228 (S4 is confined close to C136 (S1 of an adjacent VSD. Structural modeling predicts that in the closed to open transition, an axial rotation (approximately 190 degrees and outward translation of S4 (approximately 12 A is accompanied by VSD rocking. This large sensor motion changes the intra-VSD S1-S4 interaction to an inter-VSD S1-S4 interaction. These constraints provide a ground for cooperative subunit interactions and suggest a key role of the S1 segment in steering S4 motion during Kv7.1 gating.

Study of spin-polaron formation in 1D systems

International Nuclear Information System (INIS)

Arredondo, Y.; Navarro, O.; Vallejo, E.

2014-01-01

We study numerically the formation of spin-polarons in low-dimensional systems. We consider a ferromagnetic Kondo lattice model with Hund coupling J H and localized spins interacting antiferromagnetically with coupling constant J. We investigate the ground state phase diagram as a function of the exchange couplings J H and J and as a function of the band filling, since it has been observed that doping either on the ferromagnetic or antiferromagnetic regime lead to formation of magnetic domains [1]. We explore the quasi-particle formation and phase separation using the density-matrix renormalization group method, which is a highly efficient method to investigate quasi-one-dimensional strongly correlated systems

Nuclear spin-lattice relaxation in nitroxide spin-label EPR

DEFF Research Database (Denmark)

Marsh, Derek

2016-01-01

that the definition of nitrogen nuclear relaxation rate Wn commonly used in the CW-EPR literature for 14N-nitroxyl spin labels is inconsistent with that currently adopted in time-resolved EPR measurements of saturation recovery. Redefinition of the normalised 14N spin-lattice relaxation rate, b = Wn/(2We), preserves...... of spin-lattice relaxation in this three-level system. Expressions for CW-saturation EPR with the revised definitions are summarised. Data on nitrogen nuclear spin-lattice relaxation times are compiled according to the three-level scheme for 14N-relaxation: T1 n = 1/Wn. Results are compared and contrasted...

Novel spin dynamics in ferrimagnetic molecular chains from {sup 1}H NMR and {mu}SR spin-lattice relaxation measurements

Energy Technology Data Exchange (ETDEWEB)

Micotti, E. E-mail: micotti@fisicavolta.unipv.it; Lascialfari, A.; Rigamonti, A.; Aldrovandi, S.; Caneschi, A.; Gatteschi, D.; Bogani, L

2004-05-01

The spin dynamics in the helical chain Co(hfac){sub 2}NITPhOMe has been investigated by {sup 1}H NMR and {mu}SR relaxation. In the temperature range 15spin relaxation mechanism, undetected by the magnetization measurements. From the analysis of these data, insights on this novel relaxation process are derived.

Spatial and Spin Symmetry Breaking in Semidefinite-Programming-Based Hartree-Fock Theory.

Science.gov (United States)

Nascimento, Daniel R; DePrince, A Eugene

2018-05-08

The Hartree-Fock problem was recently recast as a semidefinite optimization over the space of rank-constrained two-body reduced-density matrices (RDMs) [ Phys. Rev. A 2014 , 89 , 010502(R) ]. This formulation of the problem transfers the nonconvexity of the Hartree-Fock energy functional to the rank constraint on the two-body RDM. We consider an equivalent optimization over the space of positive semidefinite one-electron RDMs (1-RDMs) that retains the nonconvexity of the Hartree-Fock energy expression. The optimized 1-RDM satisfies ensemble N-representability conditions, and ensemble spin-state conditions may be imposed as well. The spin-state conditions place additional linear and nonlinear constraints on the 1-RDM. We apply this RDM-based approach to several molecular systems and explore its spatial (point group) and spin ( Ŝ 2 and Ŝ 3 ) symmetry breaking properties. When imposing Ŝ 2 and Ŝ 3 symmetry but relaxing point group symmetry, the procedure often locates spatial-symmetry-broken solutions that are difficult to identify using standard algorithms. For example, the RDM-based approach yields a smooth, spatial-symmetry-broken potential energy curve for the well-known Be-H 2 insertion pathway. We also demonstrate numerically that, upon relaxation of Ŝ 2 and Ŝ 3 symmetry constraints, the RDM-based approach is equivalent to real-valued generalized Hartree-Fock theory.

Simplifying the complex 1H NMR spectra of fluorine-substituted benzamides by spin system filtering and spin-state selection: multiple-quantum-single-quantum correlation.

Science.gov (United States)

Baishya, Bikash; Reddy, G N Manjunatha; Prabhu, Uday Ramesh; Row, T N Guru; Suryaprakash, N

2008-10-23

The proton NMR spectra of fluorine-substituted benzamides are very complex (Figure 1) due to severe overlap of (1)H resonances from the two aromatic rings, in addition to several short and long-range scalar couplings experienced by each proton. With no detectable scalar couplings between the inter-ring spins, the (1)H NMR spectra can be construed as an overlap of spectra from two independent phenyl rings. In the present study we demonstrate that it is possible to separate the individual spectrum for each aromatic ring by spin system filtering employing the multiple-quantum-single-quantum correlation methodology. Furthermore, the two spin states of fluorine are utilized to simplify the spectrum corresponding to each phenyl ring by the spin-state selection. The demonstrated technique reduces spectral complexity by a factor of 4, in addition to permitting the determination of long-range couplings of less than 0.2 Hz and the relative signs of heteronuclear couplings. The technique also aids the judicious choice of the spin-selective double-quantum-single-quantum J-resolved experiment to determine the long-range homonuclear couplings of smaller magnitudes.

General structure of a two-body operator for spin-(1/2) particles

International Nuclear Information System (INIS)

Ershov, S.N.

2004-01-01

A direct derivation of the operator structure for two spin-(1/2) particles is presented subject to invariance under basic symmetries and Galilean frame transformation. The partial wave decomposition for coefficient functions, valid on- and off-shell, is explicitly deduced. The momentum transfer representation and angular momentum decomposition for general spin-dependent potentials are obtained

Absence of high-temperature ballistic transport in the spin-1/2 XXX chain within the grand-canonical ensemble

Science.gov (United States)

Carmelo, J. M. P.; Prosen, T.

2017-01-01

Whether in the thermodynamic limit, vanishing magnetic field h → 0, and nonzero temperature the spin stiffness of the spin-1/2 XXX Heisenberg chain is finite or vanishes within the grand-canonical ensemble remains an unsolved and controversial issue, as different approaches yield contradictory results. Here we provide an upper bound on the stiffness and show that within that ensemble it vanishes for h → 0 in the thermodynamic limit of chain length L → ∞, at high temperatures T → ∞. Our approach uses a representation in terms of the L physical spins 1/2. For all configurations that generate the exact spin-S energy and momentum eigenstates such a configuration involves a number 2S of unpaired spins 1/2 in multiplet configurations and L - 2 S spins 1/2 that are paired within Msp = L / 2 - S spin-singlet pairs. The Bethe-ansatz strings of length n = 1 and n > 1 describe a single unbound spin-singlet pair and a configuration within which n pairs are bound, respectively. In the case of n > 1 pairs this holds both for ideal and deformed strings associated with n complex rapidities with the same real part. The use of such a spin 1/2 representation provides useful physical information on the problem under investigation in contrast to often less controllable numerical studies. Our results provide strong evidence for the absence of ballistic transport in the spin-1/2 XXX Heisenberg chain in the thermodynamic limit, for high temperatures T → ∞, vanishing magnetic field h → 0 and within the grand-canonical ensemble.

POLARIZED BEAMS: 1 - Longitudinal electron spin polarization at HERA

Energy Technology Data Exchange (ETDEWEB)

Anon.

1994-09-15

Wednesday 4 May marked a turning point in the art of the manipulation of spins in electron storage rings: longitudinal electron spin polarization (with the spins oriented along the electrons' direction of motion) was established in the electron ring of HERA, the electronproton collider at DESY in Hamburg. A polarization level of about 55% was obtained and polarizations of over 60% were reproducibly obtained in the following days. The beam energy was 27.52 GeV, corresponding to half integer spin tune of 62.5.

Solid state NMR of spin-1/2 nuclei

International Nuclear Information System (INIS)

Wind, R.A.

1991-01-01

The detection of nuclear magnetic resonance by Bloch et al. and Purcell and co-workers in 1946 has led to the development of one of the most powerful spectroscopic techniques known today. The reason is that, besides the applied external magnetic field, a nuclear spin also experiences extra local magnetic fields, which are due to surrounding electron clouds (the chemical shift) and other spins. These local fields differ for nuclei located at chemically different positions in a molecule. The result is that an NMR spectrum often consists of several lines, which can be considered to be a fingerprint of the material under investigation an can assist the clarifying its molecular structure. NMR has been especially successful in liquids and liquid like materials, where fast molecular tumblings average out the anisotropies in the local fields, resulting in well-resolved NMR spectra. This paper reports that initially the development of solid-state NMR was less dramatic. Originally, for reasons of sensitivity, attention was focused mainly on 1 H NMR. The result is that the NMR spectrum usually consists of single, broad, featureless line, which, except for special cases such as more or less isolated spin pairs or methyl groups, does not provide much information

Long-lived qubit from three spin-(1/2) atoms

International Nuclear Information System (INIS)

Han Rui; Loerch, Niels; Suzuki, Jun; Englert, Berthold-Georg

2011-01-01

A system of three spin-(1/2) atoms allows the construction of a reference-frame-free (RFF) qubit in the subspace with total angular momentum j=1/2. The RFF qubit stays coherent perfectly as long as the spins of the three atoms are affected homogeneously. The inhomogeneous evolution of the atoms causes decoherence, but this decoherence can be suppressed efficiently by applying a bias magnetic field of modest strength perpendicular to the plane of the atoms. The resulting lifetime of the RFF qubit can be many days, making RFF qubits of this kind promising candidates for quantum information storage units. Specifically, we examine the situation of three 6 Li atoms trapped in a CO 2 -laser-generated optical lattice and find that, with conservatively estimated parameters, a stored qubit maintains a fidelity of 0.9999 for two hours.

Culturable bacterial endophytes isolated from Mangrove tree (Rhizophora apiculata Blume) enhance seedling growth in Rice.

Science.gov (United States)

Deivanai, Subramanian; Bindusara, Amitraghata Santhanam; Prabhakaran, Guruswamy; Bhore, Subhash Janardhan

2014-07-01

Endophytic bacteria do have several potential applications in medicine and in other various sectors of biotechnology including agriculture. Bacterial endophytes need to be explored for their potential applications in agricultural biotechnology. One of the potential applications of bacterial endophytes in agricultural is to enhance the growth of the agricultural crops. Hence, this study was undertaken to explore the plant growth promoting potential application of bacterial endophytes. The objective of this study was to examine the effect of endophytic bacteria from mangrove tree (Rhizophora apiculata Blume) for their efficacy in promoting seedling growth in rice. Eight endophytic bacterial isolates (EBIs) isolated from twig and petiole tissues of the mangrove were identified based on their 16S ribosomal ribonucleic acid (rRNA) gene sequence homology. Separately, surface sterilized paddy seeds were treated with cell-free broth and cell suspension of the EBIs. Rice seedlings were analyzed by various bioassays and data was recorded. The gene sequences of the isolates were closely related to two genera namely, Bacillus and Pantoea. Inoculation of EBIs from R. apiculata with rice seeds resulted in accelerated root and shoot growth with significant increase in chlorophyll content. Among the isolates, Pantoea ananatis (1MSE1) and Bacillus amyloliquefaciens (3MPE1) had shown predominance of activity. Endophytic invasion was recognized by the non-host by rapid accumulation of reactive oxygen species (ROS) and was counteracted by the production of hydrogen peroxide (H2O2) and lipid peroxide. The results demonstrated that EBIs from mangrove tree can increase the fitness of the rice seedlings under controlled conditions. These research findings could be useful to enhance the seedling growth and could serve as foundation in further research on enhancing the growth of the rice crop using endophytic bacteria.

Pulsar Kicks via Spin-1 Color Superconductivity

International Nuclear Information System (INIS)

Schmitt, Andreas; Shovkovy, Igor A.; Wang Qun

2005-01-01

We propose a new neutrino propulsion mechanism for neutron stars which can lead to strong velocity kicks, needed to explain the observed bimodal velocity distribution of pulsars. The spatial asymmetry in the neutrino emission is naturally provided by a stellar core containing spin-1 color-superconducting quark matter in the A phase. The neutrino propulsion mechanism switches on when the stellar core temperature drops below the transition temperature of this phase

Higher-spin currents in the Gross-Neveu model at 1/n{sup 2}

Energy Technology Data Exchange (ETDEWEB)

Manashov, A.N. [Institut für Theoretische Physik, Universität Hamburg,Hamburg, D-22761 (Germany); Institut für Theoretische Physik, Universität Regensburg,Regensburg, D-93040 (Germany); Skvortsov, E.D. [Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians University Munich, Theresienstr. 37, Munich, D-80333 (Germany); Lebedev Institute of Physics,Leninsky ave. 53, Moscow, 119991 (Russian Federation)

2017-01-30

We calculate the anomalous dimensions of higher-spin currents, both singlet and non-singlet, in the Gross-Neveu model at the 1/n{sup 2} order. It was conjectured that in the critical regime this model is dual to a higher-spin gauge theory on AdS{sub 4}. The AdS/CFT correspondence predicts that the masses of higher-spin fields correspond to the scaling dimensions of the singlet currents in the Gross-Neveu model.

Thermodynamical properties of random spin-1/2 XY chain with Dzyaloshinskii-Moriya interaction

International Nuclear Information System (INIS)

Derzhko, O.; Krokhmalskii, T.; Verkholyak, T.

1995-07-01

For computation of the equilibrium statistical properties of finite spin-1/2 XY chains with Dzyaloshinskii-Moriya interaction the suggested earlier approach (JMMM 140-144 (1995) 1623) is generalized. It is applied for calculation of transverse dynamical susceptibility of spin-1/2 Ising chain in non-random and random Gaussian transverse field with Dzyaloshinskii-Moriya interaction. (author). 7 refs, 2 figs

Preparation and biological evaluation of conformationally constrained BACE1 inhibitors.

Science.gov (United States)

Winneroski, Leonard L; Schiffler, Matthew A; Erickson, Jon A; May, Patrick C; Monk, Scott A; Timm, David E; Audia, James E; Beck, James P; Boggs, Leonard N; Borders, Anthony R; Boyer, Robert D; Brier, Richard A; Hudziak, Kevin J; Klimkowski, Valentine J; Garcia Losada, Pablo; Mathes, Brian M; Stout, Stephanie L; Watson, Brian M; Mergott, Dustin J

2015-07-01

The BACE1 enzyme is a key target for Alzheimer's disease. During our BACE1 research efforts, fragment screening revealed that bicyclic thiazine 3 had low millimolar activity against BACE1. Analysis of the co-crystal structure of 3 suggested that potency could be increased through extension toward the S3 pocket and through conformational constraint of the thiazine core. Pursuit of S3-binding groups produced low micromolar inhibitor 6, which informed the S3-design for constrained analogs 7 and 8, themselves prepared via independent, multi-step synthetic routes. Biological characterization of BACE inhibitors 6-8 is described. Copyright © 2015 Elsevier Ltd. All rights reserved.

1H, 13C and 13N chemical shifts and 1H-15N and 13C-15N heteronuclear spin-spin coupling constants n the NMR spectra of 5-substituted furfural oximes

International Nuclear Information System (INIS)

Popelis, Yu.Yu.; Liepin'sh, E.E.; Lukevits, E.Ya.

1986-01-01

The 1 H, 13 C, and 15 N NMR spectra of 15 N-enriched 5-substituted furfural oximes were investigated. It was shown that the chemical shifts of the ring atoms and the oxime group correlate satisfactorily with the F and R substituent constants, whereas their sensitivity to the effect of the substituents is lower than in monosubstituted furan derivatives. The constants of spin-spin coupling between the ring protons and the oxime group were determined. An analysis of the 1 H- 1 H spin-spin coupling constants (SSCC) on the basis of their stereospecificity indicates that the E isomers have primarily an s-trans conformation in polar dimethyl sulfoxide, whereas the Z isomers, on the other hand, have an s-cis conformation. The signs of the direct and geminal 13 C- 15 N SSCC were determined for 5-trimethylsilylfurfural oxime

Spin relaxation through Kondo scattering in Cu/Py lateral spin valves

Science.gov (United States)

Batley, J. T.; Rosaond, M. C.; Ali, M.; Linfield, E. H.; Burnell, G.; Hickey, B. J.

Within non-magnetic metals it is reasonable to expect the Elliot-Yafet mechanism to govern spin-relaxation and thus the temperature dependence of the spin diffusion length might be inversely proportional to resistivity. However, in lateral spin valves, measurements have found that at low temperatures the spin diffusion length unexpectedly decreases. We have fabricated lateral spin valves from Cu with different concentrations of magnetic impurities. Through temperature dependent charge and spin transport measurements we present clear evidence linking the presence of the Kondo effect within Cu to the suppression of the spin diffusion length below 30 K. We have calculated the spin-relaxation rate and isolated the contribution from magnetic impurities. At very low temperatures electron-electron interactions play a more prominent role in the Kondo effect. Well below the Kondo temperature a strong-coupling regime exists, where the moments become screened and the magnetic dephasing rate is reduced. We also investigate the effect of this low temperature regime (>1 K) on a pure spin current. This work shows the dominant role of Kondo scattering, even in low concentrations of order 1 ppm, within pure spin transport.

CrAs(0 0 1)/AlAs(0 0 1) heterogeneous junction as a spin current diode predicted by first-principles calculations

International Nuclear Information System (INIS)

Min, Y.; Yao, K.L.; Liu, Z.L.; Cheng, H.G.; Zhu, S.C.; Gao, G.Y.

2009-01-01

We report on first-principles calculations of spin-dependent quantum transport in a CrAs(0 0 1)/AlAs(0 0 1) heterogeneous junction and predict a strong diode effect of charge and spin current. The minority spin current is absolutely inhibited when the bias voltage is applied to the terminals of both CrAs and AlAs. The majority spin current is inhibited when the bias voltage is applied to the terminal of CrAs and 'relaxed' when the bias voltage is applied to the terminal of AlAs. The charge and spin current diode are promising for reprogrammable logic applications in the field of spintronics

Quantum phase transitions in matrix product states of one-dimensional spin-1 chains

International Nuclear Information System (INIS)

Zhu Jingmin

2014-01-01

We present a new model of quantum phase transitions in matrix product systems of one-dimensional spin-1 chains and study the phases coexistence phenomenon. We find that in the thermodynamic limit the proposed system has three different quantum phases and by adjusting the control parameters we are able to realize any phase, any two phases equal coexistence and the three phases equal coexistence. At every critical point the physical quantities including the entanglement are not discontinuous and the matrix product system has long-range correlation and N-spin maximal entanglement. We believe that our work is helpful for having a comprehensive understanding of quantum phase transitions in matrix product states of one-dimensional spin chains and of certain directive significance to the preparation and control of one-dimensional spin lattice models with stable coherence and N-spin maximal entanglement. (author)

Calculations of spin-polarized Goos-Hänchen displacement in magnetically confined GaAs/Al x Ga1-x As nanostructure modulated by spin-orbit couplings

Science.gov (United States)

Lu, Mao-Wang; Chen, Sai-Yan; Zhang, Gui-Lian; Huang, Xin-Hong

2018-04-01

We theoretically investigate Goos-Hänchen (GH) displacement by modelling the spin transport in an archetypal device structure—a magnetically confined GaAs/Al x Ga1-x As nanostructure modulated by spin-orbit coupling (SOC). Both Rashba and Dresselhaus SOCs are taken into account. The degree of spin-polarized GH displacement can be tuned by Rashba or Dresselhaus SOC, i.e. interfacial confining electric field or strain engineering. Based on such a semiconductor nanostructure, a controllable spatial spin splitter can be proposed for spintronics applications.

Calculations of spin-polarized Goos-Hänchen displacement in magnetically confined GaAs/Al x Ga1-x As nanostructure modulated by spin-orbit couplings.

Science.gov (United States)

Lu, Mao-Wang; Chen, Sai-Yan; Zhang, Gui-Lian; Huang, Xin-Hong

2018-04-11

We theoretically investigate Goos-Hänchen (GH) displacement by modelling the spin transport in an archetypal device structure-a magnetically confined GaAs/Al x Ga 1-x As nanostructure modulated by spin-orbit coupling (SOC). Both Rashba and Dresselhaus SOCs are taken into account. The degree of spin-polarized GH displacement can be tuned by Rashba or Dresselhaus SOC, i.e. interfacial confining electric field or strain engineering. Based on such a semiconductor nanostructure, a controllable spatial spin splitter can be proposed for spintronics applications.

Testing a spin-2 mediator by angular observables in b →s μ+μ-

Science.gov (United States)

Fajfer, Svjetlana; Melić, Blaženka; Patra, Monalisa

2018-05-01

We consider the effects of the spin-2 particle in the b →s μ+μ- transition assuming that the spin-2 particle couples in a flavor-nonuniversal way to b and s quarks and in the leptonic sector couples only to the muons, thereby only contributing to the process b →s μ+μ-. The Bs-B¯s transition gives the strong constraint on the coupling of the spin-2 mediator and b and s quarks, while the observed discrepancy from the standard model prediction for the muon anomalous magnetic moment (g -2 )μ serves to constrain the μ coupling to a spin-2 particle. We find that the spin-2 particle can modify the angular observables in the B →K μ+μ- and B →K*μ+μ- decays and produce effects that do not exist in the standard model. The generated forward-backward asymmetries in these processes can reach 15%, while other observables for these decays receive tiny effects.

Free-Spinning Characteristics of a 1/24-Scale Model of the Grumman F11F-1 Airplane, TED No. NACA AD 395

Science.gov (United States)

Bowman, James S., Jr.

1955-01-01

An investigation is being conducted in the Langley 20-foot free-spinning tunnel on a 1/24-scale model of the Grumman F11F-1 airplane to determine spin and recovery characteristics and the minimum-size parachute required to satisfactorily terminate the spin in an emergency. Results obtained to date are presented herein. Test results indicate that it may be difficult to obtain an erect or inverted spin on the airplane, but, if a spin is obtained, the spin will be very oscillatory and recovery from the developed erect spin by rudder reversal may not be possible. The lateral controls will have no appreciable effect on recoveries from erect.spins. Recovery from the inverted spin by merely neutralizing the rudder will be satisfactory. After recoveries by rudder reversal and after recoveries from spins without control movement (no spins), the model oftentimes rolled very rapidly about the X-axis. Based on limited preliminary tests made in this investigation to make the model recover satisfactorily, it appears that canards near the nose of the airplane or differentially operated horizontal tails may be utilized to provide rapid recoveries. The parachute test results indicate that an 11-foot-diameter (laid-out-flat) parachute with a drag coefficient of 0.650 (based on the laid- out-flat diameter) and with a towline length equal to the wing span is the minimum-size parachute required to satisfactorily terminate an erect or inverted spin in an emergency.

Control of electron spin decoherence in nuclear spin baths

Science.gov (United States)

Liu, Ren-Bao

2011-03-01

Nuclear spin baths are a main mechanism of decoherence of spin qubits in solid-state systems, such as quantum dots and nitrogen-vacancy (NV) centers of diamond. The decoherence results from entanglement between the electron and nuclear spins, established by quantum evolution of the bath conditioned on the electron spin state. When the electron spin is flipped, the conditional bath evolution is manipulated. Such manipulation of bath through control of the electron spin not only leads to preservation of the center spin coherence but also demonstrates quantum nature of the bath. In an NV center system, the electron spin effectively interacts with hundreds of 13 C nuclear spins. Under repeated flip control (dynamical decoupling), the electron spin coherence can be preserved for a long time (> 1 ms) . Thereforesomecharacteristicoscillations , duetocouplingtoabonded 13 C nuclear spin pair (a dimer), are imprinted on the electron spin coherence profile, which are very sensitive to the position and orientation of the dimer. With such finger-print oscillations, a dimer can be uniquely identified. Thus, we propose magnetometry with single-nucleus sensitivity and atomic resolution, using NV center spin coherence to identify single molecules. Through the center spin coherence, we could also explore the many-body physics in an interacting spin bath. The information of elementary excitations and many-body correlations can be extracted from the center spin coherence under many-pulse dynamical decoupling control. Another application of the preserved spin coherence is identifying quantumness of a spin bath through the back-action of the electron spin to the bath. We show that the multiple transition of an NV center in a nuclear spin bath can have longer coherence time than the single transition does, when the classical noises due to inhomogeneous broadening is removed by spin echo. This counter-intuitive result unambiguously demonstrates the quantumness of the nuclear spin bath

Finite-temperature behavior of an impurity in the spin-1/2 XXZ chain

International Nuclear Information System (INIS)

Yahagi, Ryoko; Deguchi, Tetsuo; Sato, Jun

2014-01-01

We study the zero- and the finite-temperature behavior of the integrable spin-1/2 XXZ periodic chain with an impurity by the algebraic and thermal Bethe ansatz methods. We evaluate the local magnetization on the impurity site at zero temperature analytically and derive the impurity susceptibility exactly from it. In the graphs of the impurity specific heat versus temperature, we show how the impurity spin becomes more liberated from the bulk many-body effect as the exchange coupling between the impurity spin and other spins decreases and that at low temperature it couples strongly to them such as in the Kondo effect. Thus, we observe not only the crossover behavior from the high- to the low-temperature regime, but another from the N-site chain to the (N − 1)-site chain with a free impurity spin. We also show that the estimate of the Wilson ratio at a given low temperature is independent of the impurity parameter if its absolute value is small enough with respect to the temperature and the universality class is described by the XXZ anisotropy in terms of the dressed charge. (paper)

Effect of leaf extract buasbuas (Premna pubescens Blume) for against of bacteria growth Staphylococcus aureus and Salmonella sp in vitro

Science.gov (United States)

Restuati, Martina; Pratiwi, Nanda; Widiyastuti, Gita

2017-08-01

Buasbuas (Premna pubescens Blume) is the one of the medicinal plants in Indonesia. This plant contains flavonoids potential as an antibacterial. Staphylococcus aureus and Salmonella sp is the one of the bacteria that can cause poisoning. This research aims to find out of inhibitory the extract of buasbuas leaves the growth of Staphylococcus aureus and Salmonella sp. This research was conducted in Medan Health Laboratory used hole sinks methods. Buasbuas leaves which has been condensed ethanol extract was diluted using aquadest with a concentration of 0%, 50%, 60%, 70%, 80%, 90% and dropped into MSA (Mannitol Salt Agar) media inoculated bacteria and wich is a hole sinks. Them incubated for 1 × 24 hours at a temperature of 37°C. The results of this research that the buasbuas extract with the different concentrations can inhibit the growth of Staphylococcus aureus, then the result were analyzed used of Non Factorial Experimental Method (ANOVA) where Fcount (337.54)> Ftable 0,05 (2,77); Ftabel 0.01 (4.25). While the maximum concentration buasbuas extract were more effective the growh of bacteria is 90% with average inhibition zone diameter of 11 mm.

Study of spin-polaron formation in 1D systems

Energy Technology Data Exchange (ETDEWEB)

Arredondo, Y.; Navarro, O. [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Apartado Postal 70-360, 04510 México D.F. (Mexico); Vallejo, E. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Coahuila, Carretera Torreón-Matamoros Km. 7.5 Ciudad Universitaria, 27276 Torreón, Coahuila (Mexico)

2014-05-15

We study numerically the formation of spin-polarons in low-dimensional systems. We consider a ferromagnetic Kondo lattice model with Hund coupling J{sub H} and localized spins interacting antiferromagnetically with coupling constant J. We investigate the ground state phase diagram as a function of the exchange couplings J{sub H} and J and as a function of the band filling, since it has been observed that doping either on the ferromagnetic or antiferromagnetic regime lead to formation of magnetic domains [1]. We explore the quasi-particle formation and phase separation using the density-matrix renormalization group method, which is a highly efficient method to investigate quasi-one-dimensional strongly correlated systems.

Higher spin currents in the critical O(N) vector model at 1/N2

International Nuclear Information System (INIS)

Manashov, A.N.; Strohmaier, M.

2017-06-01

We calculate the anomalous dimensions of higher spin singlet currents in the critical O(N) vector model at order 1/N 2 . The results are shown to be in agreement with the four-loop perturbative computation in φ 4 theory in 4-2ε dimensions. It is known that the order 1/N anomalous dimensions of higher-spin currents happen to be the same in the Gross-Neveu and the critical vector model. On the contrary, the order 1/N 2 corrections are different. The results can also be interpreted as a prediction for the two-loop computation in the dual higher-spin gravity.

Entanglement entropy in random quantum spin-S chains

International Nuclear Information System (INIS)

Saguia, A.; Boechat, B.; Continentino, M. A.; Sarandy, M. S.

2007-01-01

We discuss the scaling of entanglement entropy in the random singlet phase (RSP) of disordered quantum magnetic chains of general spin S. Through an analysis of the general structure of the RSP, we show that the entanglement entropy scales logarithmically with the size of a block, and we provide a closed expression for this scaling. This result is applicable for arbitrary quantum spin chains in the RSP, being dependent only on the magnitude S of the spin. Remarkably, the logarithmic scaling holds for the disordered chain even if the pure chain with no disorder does not exhibit conformal invariance, as is the case for Heisenberg integer-spin chains. Our conclusions are supported by explicit evaluations of the entanglement entropy for random spin-1 and spin-3/2 chains using an asymptotically exact real-space renormalization group approach

The integrable quantum group invariant A2n-1(2) and Dn+1(2) open spin chains

Science.gov (United States)

Nepomechie, Rafael I.; Pimenta, Rodrigo A.; Retore, Ana L.

2017-11-01

A family of A2n(2) integrable open spin chains with Uq (Cn) symmetry was recently identified in arxiv:arXiv:1702.01482. We identify here in a similar way a family of A2n-1(2) integrable open spin chains with Uq (Dn) symmetry, and two families of Dn+1(2) integrable open spin chains with Uq (Bn) symmetry. We discuss the consequences of these symmetries for the degeneracies and multiplicities of the spectrum. We propose Bethe ansatz solutions for two of these models, whose completeness we check numerically for small values of n and chain length N. We find formulas for the Dynkin labels in terms of the numbers of Bethe roots of each type, which are useful for determining the corresponding degeneracies. In an appendix, we briefly consider Dn+1(2) chains with other integrable boundary conditions, which do not have quantum group symmetry.

The integrable quantum group invariant A2n−1(2 and Dn+1(2 open spin chains

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Rafael I. Nepomechie

2017-11-01

Full Text Available A family of A2n(2 integrable open spin chains with Uq(Cn symmetry was recently identified in arXiv:1702.01482. We identify here in a similar way a family of A2n−1(2 integrable open spin chains with Uq(Dn symmetry, and two families of Dn+1(2 integrable open spin chains with Uq(Bn symmetry. We discuss the consequences of these symmetries for the degeneracies and multiplicities of the spectrum. We propose Bethe ansatz solutions for two of these models, whose completeness we check numerically for small values of n and chain length N. We find formulas for the Dynkin labels in terms of the numbers of Bethe roots of each type, which are useful for determining the corresponding degeneracies. In an appendix, we briefly consider Dn+1(2 chains with other integrable boundary conditions, which do not have quantum group symmetry.

Equivalence of ADM Hamiltonian and Effective Field Theory approaches at next-to-next-to-leading order spin1-spin2 coupling of binary inspirals

Energy Technology Data Exchange (ETDEWEB)

Levi, Michele [Institut d' Astrophysique de Paris, Université Pierre et Marie Curie, CNRS-UMR 7095, 98 bis Boulevard Arago, 75014 Paris (France); Steinhoff, Jan, E-mail: michele.levi@upmc.fr, E-mail: jan.steinhoff@ist.utl.pt [Centro Multidisciplinar de Astrofisica, Instituto Superior Tecnico, Universidade de Lisboa, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal)

2014-12-01

The next-to-next-to-leading order spin1-spin2 potential for an inspiralling binary, that is essential for accuracy to fourth post-Newtonian order, if both components in the binary are spinning rapidly, has been recently derived independently via the ADM Hamiltonian and the Effective Field Theory approaches, using different gauges and variables. Here we show the complete physical equivalence of the two results, thereby we first prove the equivalence of the ADM Hamiltonian and the Effective Field Theory approaches at next-to-next-to-leading order with the inclusion of spins. The main difficulty in the spinning sectors, which also prescribes the manner in which the comparison of the two results is tackled here, is the existence of redundant unphysical spin degrees of freedom, associated with the spin gauge choice of a point within the extended spinning object for its representative worldline. After gauge fixing and eliminating the unphysical degrees of freedom of the spin and its conjugate at the level of the action, we arrive at curved spacetime generalizations of the Newton-Wigner variables in closed form, which can also be used to obtain further Hamiltonians, based on an Effective Field Theory formulation and computation. Finally, we make use of our validated result to provide gauge invariant relations among the binding energy, angular momentum, and orbital frequency of an inspiralling binary with generic compact spinning components to fourth post-Newtonian order, including all known sectors up to date.

Out-of-plane spin-orientation dependent magnetotransport properties in the anisotropic helimagnet CR1/3NbS2 [Spin-Orbit Coupling Induced Anisotropy in the Magnetotransport of the Chiral Helimagnet Cr1=3NbS2

International Nuclear Information System (INIS)

Bornstein, Alexander C.; Chapman, Benjamin J.; Ghimire, Nirmal J.; Oak Ridge National Lab.; Technology Div.); Mandrus, David G.; Oak Ridge National Lab.; Technology Div.); Parker, David S.; Technology Div.); Lee, Minhyea

2015-01-01

Understanding the role of spin-orbit coupling (SOC) has been crucial for controlling magnetic anisotropy in magnetic multilayer films. It has been shown that electronic structure can be altered via interface SOC by varying the superlattice structure, resulting in spontaneous magnetization perpendicular or parallel to the plane. In lieu of magnetic thin films, we study the similarly anisotropic helimagnet Cr1/3NbS2 where the spin-polarization direction, controlled by the applied magnetic field, can modify the electronic structure. As a result, the direction of spin polarization can modulate the density of states and in turn affect the in-plane electrical conductivity. In Cr1/3NbS2, we found an enhancement of in-plane conductivity when the spin polarization is out-of-plane as compared to in-plane spin polarization. This is consistent with the increase in density of states near the Fermi energy at the same spin configuration, found from first-principles calculations. We also observe unusual field dependence of the Hall signal in the same temperature range. This is unlikely to originate from the noncollinear spin texture but rather further indicates strong dependence of electronic structure on spin orientation relative to the plane

Generalized spin Sutherland systems revisited

Directory of Open Access Journals (Sweden)

L. Fehér

2015-04-01

Full Text Available We present generalizations of the spin Sutherland systems obtained earlier by Blom and Langmann and by Polychronakos in two different ways: from SU(n Yang–Mills theory on the cylinder and by constraining geodesic motion on the N-fold direct product of SU(n with itself, for any N>1. Our systems are in correspondence with the Dynkin diagram automorphisms of arbitrary connected and simply connected compact simple Lie groups. We give a finite-dimensional as well as an infinite-dimensional derivation and shed light on the mechanism whereby they lead to the same classical integrable systems. The infinite-dimensional approach, based on twisted current algebras (alias Yang–Mills with twisted boundary conditions, was inspired by the derivation of the spinless Sutherland model due to Gorsky and Nekrasov. The finite-dimensional method relies on Hamiltonian reduction under twisted conjugations of N-fold direct product groups, linking the quantum mechanics of the reduced systems to representation theory similarly as was explored previously in the N=1 case.

The spin-dependent structure function g1 of the deuteron

International Nuclear Information System (INIS)

Bueltmann, S.

1996-01-01

Results on the spin-dependent structure function g 1 d of the deuteron measured by the Spin Muon Collaboration at CERN are presented. They are based on deep-inelastic scattering of 190 GeV polarized muons off a polarized deuteron target in the kinematic range of 0.003 ≤ x Bj ≤ 0.7 and 1 GeV 2 ≤ Q 2 ≤ 60 GeV 2 . The structure function is found to be negative for small values of x Bj , while the proton structure function g 1 p measured earlier by the SMC is positive over the whole x Bj -range. The Bjorken sum rule is in good agreement with the first moments of the structure functions, while the Ellis-Jaffe sum rule is violated by more than three standard deviations for the deuteron measurement. (author)

Coupled dynamics of interacting spin-1 bosons in a double-well potential

Science.gov (United States)

Carvalho, D. W. S.; Foerster, A.; Gusmão, M. A.

2018-03-01

We present a detailed analysis of dynamical processes involving two or three particles in a double-well potential. Motivated by experimental realizations of such a system with optically trapped cold atoms, we focus on spin-1 bosons with special attention on the effects of a spin-dependent interaction in addition to the usual Hubbard-like repulsive one. For a sufficiently weak tunneling amplitude in comparison to the dominant Hubbard coupling, particle motion is strongly correlated, occurring only under fine-tuned relationships between well-depth asymmetry and interactions. We highlight processes involving tunneling of coupled particle pairs and triads, emphasizing the role of the spin-dependent interaction in resonance conditions.

Absence of high-temperature ballistic transport in the spin-1/2 XXX chain within the grand-canonical ensemble

Directory of Open Access Journals (Sweden)

J.M.P. Carmelo

2017-01-01

Full Text Available Whether in the thermodynamic limit, vanishing magnetic field h→0, and nonzero temperature the spin stiffness of the spin-1/2 XXX Heisenberg chain is finite or vanishes within the grand-canonical ensemble remains an unsolved and controversial issue, as different approaches yield contradictory results. Here we provide an upper bound on the stiffness and show that within that ensemble it vanishes for h→0 in the thermodynamic limit of chain length L→∞, at high temperatures T→∞. Our approach uses a representation in terms of the L physical spins 1/2. For all configurations that generate the exact spin-S energy and momentum eigenstates such a configuration involves a number 2S of unpaired spins 1/2 in multiplet configurations and L−2S spins 1/2 that are paired within Msp=L/2−S spin–singlet pairs. The Bethe-ansatz strings of length n=1 and n>1 describe a single unbound spin–singlet pair and a configuration within which n pairs are bound, respectively. In the case of n>1 pairs this holds both for ideal and deformed strings associated with n complex rapidities with the same real part. The use of such a spin 1/2 representation provides useful physical information on the problem under investigation in contrast to often less controllable numerical studies. Our results provide strong evidence for the absence of ballistic transport in the spin-1/2 XXX Heisenberg chain in the thermodynamic limit, for high temperatures T→∞, vanishing magnetic field h→0 and within the grand-canonical ensemble.

Ocorrência de Salmonella e coliformes de origem fecal na canela em pó (Cinnamomum cassia Blume a Cinnamomum zeylanicum Nees comercializada em Florianópolis, Santa Catarina, Brasil Salmonella and fecal coliforms in cinnamon (Cinnamomum cassia Blume and Cinnamomum zeylanicum Nees sold in the city of Florianópolis, Santa Catarina, Brazil

Directory of Open Access Journals (Sweden)

Jane Maria de S. Philippi

1995-12-01

Full Text Available Cem amostras de canela em pó de dez marcas diferentes comercializadas na cidade de Florianópolis, SC, foram submetidas à análise microbiológica, pesquisando-se Salmonella e coliformes de origem fecal. Em nenhuma amostra foi detectada Salmonella. Coliformes de origem fecal foram encontrados entre os valores The microbiological quality of a hundred samples of ten differents commercial brands of a ground cinnamon (Cinnamomum cassia Blume and Cinnamomum zeylanicum Nees from supermarkets in the city of Florianópolis, Brazil, was assessed. Salmonella and fecal coliforms were determined. Results were negative for Salmonella Fecal coliforms values ranged from 100 MPN per g. Fecal coliforms were detected in 37% of the cinnamon samples.

Neoclassical theory of elementary charges with spin of 1/2

Energy Technology Data Exchange (ETDEWEB)

Babin, Anatoli; Figotin, Alexander [Department of Mathematics University of California at Irvine, Irvine, California 92697-3875 (United States)

2014-08-15

We advance here our neoclassical theory of elementary charges by integrating into it the concept of spin of 1/2. The developed spinorial version of our theory has many important features identical to those of the Dirac theory such as the gyromagnetic ratio, expressions for currents including the spin current, and antimatter states. In our theory, the concepts of charge and anticharge relate naturally to their “spin” in its rest frame in two opposite directions. An important difference with the Dirac theory is that both the charge and anticharge energies are positive whereas their frequencies have opposite signs.

Spin polarized deuterium

International Nuclear Information System (INIS)

Glyde, H.R.; Hernadi, S.I.

1986-01-01

Several ground state properties of (electron) spin-polarized deuterium (D) such as the energy, single quasiparticle energies and lifetimes, Landau parameters and sound velocities are evaluated. The calculations begin with the Kolos-Wolneiwicz potential and use the Galitskii-FeynmanHartree-Fock (GFHF) approximation. The deuteron nucleas has spin I = 1, and spin states I/sub z/ = 1,0,-1. We explore D 1 , D 2 and D 3 in which, respectively, one spin state only is populated, two states are equally populated, and three states are equally populated. We find the GFHF describes D 1 well, but D 2 and D 3 less well. The Landau parameters, F/sub L/, are small compared to liquid 3 He and very small for doubly polarized D 1 (i.e. the F/sub L/ decrease with nuclear polarization)

Bodily tides near the 1:1 spin-orbit resonance: correction to Goldreich's dynamical model

Science.gov (United States)

Williams, James G.; Efroimsky, Michael

2012-12-01

Spin-orbit coupling is often described in an approach known as " the MacDonald torque", which has long become the textbook standard due to its apparent simplicity. Within this method, a concise expression for the additional tidal potential, derived by MacDonald (Rev Geophys 2:467-541, 1994), is combined with a convenient assumption that the quality factor Q is frequency-independent (or, equivalently, that the geometric lag angle is constant in time). This makes the treatment unphysical because MacDonald's derivation of the said formula was, very implicitly, based on keeping the time lag frequency-independent, which is equivalent to setting Q scale as the inverse tidal frequency. This contradiction requires the entire MacDonald treatment of both non-resonant and resonant rotation to be rewritten. The non-resonant case was reconsidered by Efroimsky and Williams (Cel Mech Dyn Astron 104:257-289, 2009), in application to spin modes distant from the major commensurabilities. In the current paper, we continue this work by introducing the necessary alterations into the MacDonald-torque-based model of falling into a 1-to-1 resonance. (The original version of this model was offered by Goldreich (Astron J 71:1-7, 1996). Although the MacDonald torque, both in its original formulation and in its corrected version, is incompatible with realistic rheologies of minerals and mantles, it remains a useful toy model, which enables one to obtain, in some situations, qualitatively meaningful results without resorting to the more rigorous (and complicated) theory of Darwin and Kaula. We first address this simplified model in application to an oblate primary body, with tides raised on it by an orbiting zero-inclination secondary. (Here the role of the tidally-perturbed primary can be played by a satellite, the perturbing secondary being its host planet. A planet may as well be the perturbed primary, its host star acting as the tide-raising secondary). We then extend the model to a

Spin injection into semiconductors: the role of Fe/AlxGa1-xAs interface

International Nuclear Information System (INIS)

Fitzsimmons, M.R.; Park, S.

2004-01-01

The influence of the growth and post-growth annealing temperatures of Fe/Al x Ga 1-x As-based spin light-emitting diodes (LEDs) on the spin injection efficiency is discussed. The extent of interfacial reactions during molecular beam epitaxial growth of Fe on GaAs was determined from in-situ x-ray photoelectron spectroscopy studies. The Fe/GaAs interface results in ≤ 3 monolayers of reaction for Fe grown at -15 C. Intermediate growth temperatures (95 C) lead to ∼5 monolayers of interfacial reactions, and high growth temperatures of 175 C lead to a ∼9 monolayer thick reacted layer. Polarized neutron reflectivity was used to determine the interfacial magnetic properties of epitaxial Fe 0.5 Co 0.5 /GaAs heterostructures grown under identical conditions. No interfacial magnetic dead layer is detected at the interface for Fe 0.5 Co 0.5 films grown at -15 C, an ∼6 (angstrom) thick nonmagnetic layer formed at the interface for 95 C growth and an ∼5 (angstrom) thick magnetic interfacial reacted layer formed for growth at 175 C. Spin injection from Fe contacts into spin LEDs decreases sharply when reactions result in a nonmagnetic interfacial layer. Significant spin injection signals are obtained from Fe contacts grown between -5 C and 175 C, although the higher Fe growth temperatures resulted in a change in the sign of the spin polarization. Post-growth annealing of the spin LEDs is found to increase spin injection efficiency for low Fe growth temperatures and to a sign reversal of the spin polarization for high growth temperature (175 C). An effective Schottky barrier height increase indicates that post growth annealing modifies the Fe/Al x Ga 1-x As interface.

The spin-s quantum Heisenberg ferromagnetic models in the physical magnon theory

International Nuclear Information System (INIS)

Liu, B.-G.; Pu, F.-C.

2001-01-01

The spin-s quantum Heisenberg ferromagnetic model is investigated in the physical magnon theory. The effect of the extra unphysical magnon states on every site is completely removed in the magnon Hamiltonian and during approximation procedure so that the condition †n i a n i >=0(n≥2s+1) is rigorously satisfied. The physical multi-magnon occupancy †n i a n i >(1≤n≤2s) is proportional to T 3n/2 at low temperature and is equivalent to 1/(2s+1) at the Curie temperature. The magnetization not only unified but also well-behaved from zero temperature to Curie temperature is obtained in the framework of the magnon theory for the spin-s quantum Heisenberg ferromagnetic model. The ill-behaved magnetizations at high temperature in earlier magnon theories are completely corrected. The relation of magnon (spin wave) theory with spin-operator decoupling theory is clearly understood

Spin-wave resonances and surface spin pinning in Ga1-xMnxAs thin films

Science.gov (United States)

Bihler, C.; Schoch, W.; Limmer, W.; Goennenwein, S. T. B.; Brandt, M. S.

2009-01-01

We investigate the dependence of the spin-wave resonance (SWR) spectra of Ga0.95Mn0.05As thin films on the sample treatment. We find that for the external magnetic field perpendicular to the film plane, the SWR spectrum of the as-grown thin films and the changes upon etching and short-term hydrogenation can be quantitatively explained via a linear gradient in the uniaxial magnetic anisotropy field in growth direction. The model also qualitatively explains the SWR spectra observed for the in-plane easy-axis orientation of the external magnetic field. Furthermore, we observe a change in the effective surface spin pinning of the partially hydrogenated sample, which results from the tail in the hydrogen-diffusion profile. The latter leads to a rapidly changing hole concentration/magnetic anisotropy profile acting as a barrier for the spin-wave excitations. Therefore, short-term hydrogenation constitutes a simple method to efficiently manipulate the surface spin pinning.

Study of the nucleon spin structure functions: the E154 experiment at SLAC

International Nuclear Information System (INIS)

Sabatie, Franck

1998-01-01

In experiment E154 at SLAC, the spin dependent structure function g 1 n was measured by scattering longitudinally polarized 50 GeV electrons off a longitudinally polarized helium 3 target. We report the integral over the measured x range to be ∫ 0.014 0.7 g 1 n (x,5 GeV 2 )dx = -0.0348 ± 0.0033 ± 0.0043 ± 0.0014. We observe relatively large values of g 1 n at low x, calling into question the reliability of the data extrapolation down to x equal 0. Such a divergent behavior seems to disagree with the prediction of the Regge theory but can be quantitatively explained by perturbative QCD. Moreover, we have performed a NLO perturbative QCD analysis of the world data on g 1 , paying careful attention to both the theoretical hypothesis and the calculation of errors. Using a parametrization of the polarized parton distribution at a low scale, we can access the fraction of spin carried by quarks: ΔΣ = 29 ± 6 pc in the MS-bar scheme, and ΔΣ = 37 ± 7 pc in the AB scheme. The gluon contribution to the nucleon spin is not well enough constrained by the current data, but seems to lie between 0 and 2. This study allows us to extract the first moment of the g 1 structure function and we find agreement with the Bjorken sum rule expectations. (author) [fr

Spin precession and spin Hall effect in monolayer graphene/Pt nanostructures

Science.gov (United States)

Savero Torres, W.; Sierra, J. F.; Benítez, L. A.; Bonell, F.; Costache, M. V.; Valenzuela, S. O.

2017-12-01

Spin Hall effects have surged as promising phenomena for spin logics operations without ferromagnets. However, the magnitude of the detected electric signals at room temperature in metallic systems has been so far underwhelming. Here, we demonstrate a two-order of magnitude enhancement of the signal in monolayer graphene/Pt devices when compared to their fully metallic counterparts. The enhancement stems in part from efficient spin injection and the large spin resistance of graphene but we also observe 100% spin absorption in Pt and find an unusually large effective spin Hall angle of up to 0.15. The large spin-to-charge conversion allows us to characterise spin precession in graphene under the presence of a magnetic field. Furthermore, by developing an analytical model based on the 1D diffusive spin-transport, we demonstrate that the effective spin-relaxation time in graphene can be accurately determined using the (inverse) spin Hall effect as a means of detection. This is a necessary step to gather full understanding of the consequences of spin absorption in spin Hall devices, which is known to suppress effective spin lifetimes in both metallic and graphene systems.

Effect of hydro-ethanolic extracts of cinnamon (Cinnamomum zeylanicum Blume and common horsetail (Equisetum arvense L. on incidence and severity of Botrytis cinerea on strawberry

Directory of Open Access Journals (Sweden)

Pazmiño-Miranda Pilar

2017-05-01

Full Text Available The effect of application of three dosages (5, 10 and 15 mL/L and two frequencies (each 6 and 8 days of ethanoic extracts obtained from cinnamon (Cinnamomum zeylanicum Blume and common horsetail (Equisetum arvense L. on incidence and severity of grey mould (Botrytis cinerea on strawberry crop (Fragaria ananassa cv. Albion was evaluated. Experiment was carried out in a randomized block design with factorial arrangement 2 x 3 x 2 + 1, with three replications. Lower incidence and severity percentage in flower and fruit (10.24 and 24.43%, respectively were observed after application of cinnamon extract at 15 mL/L at 6 days interval. Similarly, lower fruit severity (11.86% was observed with the same treatment. In general, reduction in B. cinerea incidence and severity was lower when common horsetail extract was used, compared to cinnamon extracts. According to our results, using of cinnamon hydro-ethanoic extracts could be considered as sustainable alternative for grey mold management in strawberry crops.

Weyl and transverse diffeomorphism invariant spin-2 models in D = 2 + 1

International Nuclear Information System (INIS)

Dalmazi, Denis; Mendonca, E.L.; Santos, A.L.R. dos; Ghosh, Subir

2017-01-01

There are two covariant descriptions of massless spin-2 particles in D = 3 + 1 via a symmetric rank-2 tensor: the linearized Einstein-Hilbert (LEH) theory and the Weyl plus transverse diffeomorphism (WTDIFF) invariant model. From the LEH theory one can obtain the linearized new massive gravity (NMG) in D = 2 + 1 via Kaluza-Klein dimensional reduction followed by a dual master action. Here we show that a similar route takes us from the WTDIFF model to a linearized scalar-tensor NMG which belongs to a larger class of consistent spin-0 modifications of NMG. We also show that a traceless master action applied to a parity singlet furnishes two new spin-2 self-dual models. Moreover, we examine the singular replacement h_μ_ν → h_μ_ν - η_μ_νh/D and prove that it leads to consistent massive spin-2 models in D = 2 + 1. They include linearized versions of unimodular topologically massive gravity (TMG) and unimodular NMG. Although the free part of those unimodular theories are Weyl invariant, we do not expect any improvement in the renormalizability. Both the linearized K-term (in NMG) and the linearized gravitational Chern-Simons term (in TMG) are invariant under longitudinal reparametrizations δh_μ_ν = ∂_μ∂_νζ, which is not a symmetry of the WTDIFF Einstein-Hilbert term. Therefore, we still have one degree of freedom whose propagator behaves like 1/p"2 for large momentum. (orig.)

Weyl and transverse diffeomorphism invariant spin-2 models in D=2+1

Science.gov (United States)

Dalmazi, Denis; dos Santos, A. L. R.; Ghosh, Subir; Mendonça, E. L.

2017-09-01

There are two covariant descriptions of massless spin-2 particles in D=3+1 via a symmetric rank-2 tensor: the linearized Einstein-Hilbert (LEH) theory and the Weyl plus transverse diffeomorphism (WTDIFF) invariant model. From the LEH theory one can obtain the linearized new massive gravity (NMG) in D=2+1 via Kaluza-Klein dimensional reduction followed by a dual master action. Here we show that a similar route takes us from the WTDIFF model to a linearized scalar-tensor NMG which belongs to a larger class of consistent spin-0 modifications of NMG. We also show that a traceless master action applied to a parity singlet furnishes two new spin-2 self-dual models. Moreover, we examine the singular replacement h_{μ ν } → h_{μ ν } - η _{μ ν }h/D and prove that it leads to consistent massive spin-2 models in D=2+1. They include linearized versions of unimodular topologically massive gravity (TMG) and unimodular NMG. Although the free part of those unimodular theories are Weyl invariant, we do not expect any improvement in the renormalizability. Both the linearized K-term (in NMG) and the linearized gravitational Chern-Simons term (in TMG) are invariant under longitudinal reparametrizations δ h_{μ ν } = partial _{μ }partial _{ν }ζ , which is not a symmetry of the WTDIFF Einstein-Hilbert term. Therefore, we still have one degree of freedom whose propagator behaves like 1/p^2 for large momentum.

Entangled spins and ghost-spins

Directory of Open Access Journals (Sweden)

Dileep P. Jatkar

2017-09-01

Full Text Available We study patterns of quantum entanglement in systems of spins and ghost-spins regarding them as simple quantum mechanical toy models for theories containing negative norm states. We define a single ghost-spin as in [20] as a 2-state spin variable with an indefinite inner product in the state space. We find that whenever the spin sector is disentangled from the ghost-spin sector (both of which could be entangled within themselves, the reduced density matrix obtained by tracing over all the ghost-spins gives rise to positive entanglement entropy for positive norm states, while negative norm states have an entanglement entropy with a negative real part and a constant imaginary part. However when the spins are entangled with the ghost-spins, there are new entanglement patterns in general. For systems where the number of ghost-spins is even, it is possible to find subsectors of the Hilbert space where positive norm states always lead to positive entanglement entropy after tracing over the ghost-spins. With an odd number of ghost-spins however, we find that there always exist positive norm states with negative real part for entanglement entropy after tracing over the ghost-spins.

Spin-wave stiffness in the Dzyaloshinskii-Moriya helimagnets Mn1 -xFexSi

Science.gov (United States)

Grigoriev, S. V.; Altynbaev, E. V.; Siegfried, S.-A.; Pschenichnyi, K. A.; Menzel, D.; Heinemann, A.; Chaboussant, G.

2018-01-01

The small-angle neutron scattering is used to measure the spin-wave stiffness in the field-polarized state of the Dzyaloshinskii-Moriya helimagnets Mn1 -xFexSi with x =0.03 , 0.06, 0.09, and 0.10. The Mn1 -xFexSi compounds are helically ordered below Tc and show a helical fluctuation regime above Tc in a wide range up to TDM. The critical temperatures Tc and TDM decrease with x and tend to 0 at x =0.11 and 0.17, respectively. We have found that the spin-wave stiffness A change weakly with temperature for each individual Fe-doped compound. On the other hand, the spin-wave stiffness A decreases with x duplicating the TDM dependence on x , rather than Tc(x ) . These findings classify the thermal phase transition in all Mn1 -xFexSi compounds as an abrupt change in the spin state caused, most probably, by the features of an electronic band structure. Moreover, the criticality in these compounds is not related to the value of the ferromagnetic interaction but demonstrates the remarkable role of the Dzyaloshinskii-Moriya interaction as a factor destabilizing the magnetic order.

Spin Current Noise of the Spin Seebeck Effect and Spin Pumping

Science.gov (United States)

Matsuo, M.; Ohnuma, Y.; Kato, T.; Maekawa, S.

2018-01-01

We theoretically investigate the fluctuation of a pure spin current induced by the spin Seebeck effect and spin pumping in a normal-metal-(NM-)ferromagnet(FM) bilayer system. Starting with a simple ferromagnet-insulator-(FI-)NM interface model with both spin-conserving and non-spin-conserving processes, we derive general expressions of the spin current and the spin-current noise at the interface within second-order perturbation of the FI-NM coupling strength, and estimate them for a yttrium-iron-garnet-platinum interface. We show that the spin-current noise can be used to determine the effective spin carried by a magnon modified by the non-spin-conserving process at the interface. In addition, we show that it provides information on the effective spin of a magnon, heating at the interface under spin pumping, and spin Hall angle of the NM.

The particle interpretation of N = 1 supersymmetric spin foams

Energy Technology Data Exchange (ETDEWEB)

Baccetti, Valentina [Dipartimento di Fisica ' E. Amaldi' , Universita degli Studi Roma Tre, Via della Vasca Navale 84, 00146 Roma (Italy); Livine, Etera R [Laboratoire de Physique, ENS Lyon, CNRS UMR 5672, 46 Allee d' Italie, 69007 Lyon (France); Ryan, James P, E-mail: baccetti@neve.fis.uniroma3.i, E-mail: etera.livine@ens-lyon.f, E-mail: james.ryan@aei.mpg.d [MPI fuer Gravitationsphysik, Albert Einstein Institute, Am Muehlenberg 1, D-14476 Potsdam (Germany)

2010-11-21

We show that N = 1-supersymmetric BF theory in 3D leads to a supersymmetric spin foam amplitude via a lattice discretization. Furthermore, by analysing the supersymmetric quantum amplitudes, we show that they can be re-interpreted as 3D gravity coupled to embedded fermionic Feynman diagrams.

The particle interpretation of N = 1 supersymmetric spin foams

International Nuclear Information System (INIS)

Baccetti, Valentina; Livine, Etera R; Ryan, James P

2010-01-01

We show that N = 1-supersymmetric BF theory in 3D leads to a supersymmetric spin foam amplitude via a lattice discretization. Furthermore, by analysing the supersymmetric quantum amplitudes, we show that they can be re-interpreted as 3D gravity coupled to embedded fermionic Feynman diagrams.

Spin dynamics under local gauge fields in chiral spin-orbit coupling systems

International Nuclear Information System (INIS)

Tan, S.G.; Jalil, M.B.A.; Fujita, T.; Liu, X.J.

2011-01-01

Research highlights: → We derive a modified LLG equation in magnetic systems with spin-orbit coupling (SOC). → Our results are applied to magnetic multilayers, and DMS and magnetic Rashba systems. → SOC mediated magnetization switching is predicted in rare earth metals (large SOC). → The magnetization trajectory and frequency can be modulated by applied voltage. → This facilitates potential application as tunable microwave oscillators. - Abstract: We present a theoretical description of local spin dynamics in magnetic systems with a chiral spin texture and finite spin-orbit coupling (SOC). Spin precession about the relativistic effective magnetic field in a SOC system gives rise to a non-Abelian SU(2) gauge field reminiscent of the Yang-Mills field. In addition, the adiabatic relaxation of electron spin along the local spin yields an U(1) x U(1) topological gauge (Berry) field. We derive the corresponding equation of motion i.e. modified Landau-Lifshitz-Gilbert (LLG) equation, for the local spin under the influence of these effects. Focusing on the SU(2) gauge, we obtain the spin torque magnitude, and the amplitude and frequency of spin oscillations in this system. Our theoretical estimates indicate significant spin torque and oscillations in systems with large spin-orbit coupling, which may be utilized in technological applications such as current-induced magnetization-switching and tunable microwave oscillators.

Simplified parent-child formalism for spin-0 and spin-1/2 parents

Science.gov (United States)

Butcher, J. B.; Jones, H. F.; Milani, P.

1980-06-01

We develop further the parent-child relation, that is the calculation of the cross-sections and correlations of observed particles, typically charged leptons, arising from the decay of long-lived primarily produced “parent” particles. In the high-momentum regime, when the momenta of parent and child are closely aligned, we show how, for spinless parents, the relation can be simplified by the introduction of “fragmentation” functions derived from the invariant inclusive decay distributions. We extend the formalism to the case of spin-1/2 parents and advocate its application to charm production and decay at the quark level.

Simplified parent-child formalism for spin-0 and spin- 1/2 parents

International Nuclear Information System (INIS)

Butcher, J.B.; Jones, H.F.; Milani, P.

1980-01-01

We develop further the parent-child relation, that is the calculation of the cross-sections and correlations of observed particles, typically charged leptons, arising from the decay of long-lived primarily produced 'parent' particles. In the high-momentum regime, when the momenta of parent and child are closely aligned we show how, for spinless parents, the relation can be simplified by the introduction of 'fragmentation' functions derived from the invariant inclusive decay distributions. We extend the formalism to the case of spin-1/2 parents and advocate its application to charm production and decay at the quark level. (orig.)

Spin-orbit induced electronic spin separation in semiconductor nanostructures.

Science.gov (United States)

Kohda, Makoto; Nakamura, Shuji; Nishihara, Yoshitaka; Kobayashi, Kensuke; Ono, Teruo; Ohe, Jun-ichiro; Tokura, Yasuhiro; Mineno, Taiki; Nitta, Junsaku

2012-01-01

The demonstration of quantized spin splitting by Stern and Gerlach is one of the most important experiments in modern physics. Their discovery was the precursor of recent developments in spin-based technologies. Although electrical spin separation of charged particles is fundamental in spintronics, in non-uniform magnetic fields it has been difficult to separate the spin states of charged particles due to the Lorentz force, as well as to the insufficient and uncontrollable field gradients. Here we demonstrate electronic spin separation in a semiconductor nanostructure. To avoid the Lorentz force, which is inevitably induced when an external magnetic field is applied, we utilized the effective non-uniform magnetic field which originates from the Rashba spin-orbit interaction in an InGaAs-based heterostructure. Using a Stern-Gerlach-inspired mechanism, together with a quantum point contact, we obtained field gradients of 10(8) T m(-1) resulting in a highly polarized spin current.

Spin-flip and spin orbit interactions in heavy ion systems

International Nuclear Information System (INIS)

Bybell, D.P.

1983-01-01

The role of spin orbit forces in heavy ion reactions is not completely understood. Experimental data is scarce for these systems but the data that does exist indicates a stronger spin orbit force than predicted by the folding models. The spin-flip probability of non-spin zero projectiles is one technique used for these measurements and is often taken as a direct indicator of a spin orbit interaction. This work measures the projectile spin-flip probability for three inelastic reactions; 13 C + 24 Mg, E/sub cm/ = 22.7 MeV; 13 C + 12 C, E/sub cm/ = 17.3 MeV; and 6 Li + 12 C, E/sub cm/ = 15.2 MeV, all leading to the first J/sup π/ = 2 + state of the target. The technique of particle-γ angular correlations was used for measuring the final state density matrix elements, of which the absolute value M = 1 magnetic substate population is equivalent to the spin-flip probability. The method was explored in detail and found to be sensitive to spin-flip probabilities smaller than 1%. The technique was also found to be a good indicator of the reaction mechanism involved. Nonzero and occasionally large spin-flip probabilities were observed in all systems, much larger than the folding model predictions. Information was obtained on the non-spin-flip density matrix elements. In the 13 C + 24 Mg reaction, these were found to agree with calculations when the finite size of the particle detector is included

Quantum dynamics of nuclear spins and spin relaxation in organic semiconductors

Science.gov (United States)

Mkhitaryan, V. V.; Dobrovitski, V. V.

2017-06-01

We investigate the role of the nuclear-spin quantum dynamics in hyperfine-induced spin relaxation of hopping carriers in organic semiconductors. The fast-hopping regime, when the carrier spin does not rotate much between subsequent hops, is typical for organic semiconductors possessing long spin coherence times. We consider this regime and focus on a carrier random-walk diffusion in one dimension, where the effect of the nuclear-spin dynamics is expected to be the strongest. Exact numerical simulations of spin systems with up to 25 nuclear spins are performed using the Suzuki-Trotter decomposition of the evolution operator. Larger nuclear-spin systems are modeled utilizing the spin-coherent state P -representation approach developed earlier. We find that the nuclear-spin dynamics strongly influences the carrier spin relaxation at long times. If the random walk is restricted to a small area, it leads to the quenching of carrier spin polarization at a nonzero value at long times. If the random walk is unrestricted, the carrier spin polarization acquires a long-time tail, decaying as 1 /√{t } . Based on the numerical results, we devise a simple formula describing the effect quantitatively.

Magnon Spin-Momentum Locking: Various Spin Vortices and Dirac magnons in Noncollinear Antiferromagnets

Science.gov (United States)

Okuma, Nobuyuki

2017-09-01

We generalize the concept of the spin-momentum locking to magnonic systems and derive the formula to calculate the spin expectation value for one-magnon states of general two-body spin Hamiltonians. We give no-go conditions for magnon spin to be independent of momentum. As examples of the magnon spin-momentum locking, we analyze a one-dimensional antiferromagnet with the Néel order and two-dimensional kagome lattice antiferromagnets with the 120° structure. We find that the magnon spin depends on its momentum even when the Hamiltonian has the z -axis spin rotational symmetry, which can be explained in the context of a singular band point or a U (1 ) symmetry breaking. A spin vortex in momentum space generated in a kagome lattice antiferromagnet has the winding number Q =-2 , while the typical one observed in topological insulator surface states is characterized by Q =+1 . A magnonic analogue of the surface states, the Dirac magnon with Q =+1 , is found in another kagome lattice antiferromagnet. We also derive the sum rule for Q by using the Poincaré-Hopf index theorem.

Magnon Spin-Momentum Locking: Various Spin Vortices and Dirac magnons in Noncollinear Antiferromagnets.

Science.gov (United States)

Okuma, Nobuyuki

2017-09-08

We generalize the concept of the spin-momentum locking to magnonic systems and derive the formula to calculate the spin expectation value for one-magnon states of general two-body spin Hamiltonians. We give no-go conditions for magnon spin to be independent of momentum. As examples of the magnon spin-momentum locking, we analyze a one-dimensional antiferromagnet with the Néel order and two-dimensional kagome lattice antiferromagnets with the 120° structure. We find that the magnon spin depends on its momentum even when the Hamiltonian has the z-axis spin rotational symmetry, which can be explained in the context of a singular band point or a U(1) symmetry breaking. A spin vortex in momentum space generated in a kagome lattice antiferromagnet has the winding number Q=-2, while the typical one observed in topological insulator surface states is characterized by Q=+1. A magnonic analogue of the surface states, the Dirac magnon with Q=+1, is found in another kagome lattice antiferromagnet. We also derive the sum rule for Q by using the Poincaré-Hopf index theorem.

Lagrangian-Hamiltonian formalism for the gravitational two-body problem with spin and parametrized post-Newtonian parameters γ and β

International Nuclear Information System (INIS)

Barker, B.M.; O'Connell, R.F.

1976-01-01

We generalize the Lagrangian and Hamiltonian of our previous work on the gravitational two-body problem with spin by including the parametrized-post-Newtonian parameters γ and β. By this procedure we are able to obtain the precession of the orbit as well as the precession of the spin. Equations of motion corresponding to an arbitrary-spin supplementary condition are also given. Finally we show how the masses of the binary pulsar PSR 1913 + 16 and its companion are related to the orbit and spin precessions. Combining this with a result derivable from the second-order Doppler effect and the gravitational red-shift, we obtain a relation constraining the values that γ and β can take

Excitation of bond-alternating spin-1/2 Heisenberg chains by tunnelling electrons

International Nuclear Information System (INIS)

Gauyacq, J-P; Lorente, N

2014-01-01

Inelastic electron tunneling spectra (IETS) are evaluated for spin-1/2 Heisenberg chains showing different phases of their spin ordering. The spin ordering is controlled by the value of the two different Heisenberg couplings on the two sides of each of the chain's atoms (bond-alternating chains). The perfect anti-ferromagnetic phase, i.e. a unique exchange coupling, marks a topological quantum phase transition (TQPT) of the bond-alternating chain. Our calculations show that the TQPT is recognizable in the excited states of the chain and hence that IETS is in principle capable of discriminating the phases. We show that perfectly symmetric chains, such as closed rings mimicking infinite chains, yield the same spectra on both sides of the TQPT and IETS cannot reveal the nature of the spin phase. However, for finite size open chains, both sides of the TQPT are associated with different IETS spectra, especially on the edge atoms, thus outlining the transition. (paper)

Determination of the proton spin structure functions for 0.05

Science.gov (United States)

Fersch, R. G.; Guler, N.; Bosted, P.; Deur, A.; Griffioen, K.; Keith, C.; Kuhn, S. E.; Minehart, R.; Prok, Y.; Adhikari, K. P.; Adhikari, S.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Asryan, G.; Avakian, H.; Ball, J.; Balossino, I.; Baltzell, N. A.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Thanh Cao, Frank; Carman, D. S.; Careccia, S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Djalali, C.; Dodge, G. E.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Forest, T. A.; Garçon, M.; Gavalian, G.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gleason, C.; Golovatch, E.; Gothe, R. W.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Heddle, D.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Joo, K.; Keller, D.; Khachatryan, G.; Khachatryan, M.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Lagerquist, V. G.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Movsisyan, A.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pierce, J.; Pisano, S.; Pogorelko, O.; Price, J. W.; Protopopescu, D.; Raue, B. A.; Ripani, M.; Riser, D.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Simonyan, A.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tian, Ye; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Zachariou, N.; Zhang, J.; CLAS Collaboration

2017-12-01

We present the results of our final analysis of the full data set of g1p(Q2) , the spin structure function of the proton, collected using CLAS at Jefferson Laboratory in 2000-2001. Polarized electrons with energies of 1.6, 2.5, 4.2, and 5.7 GeV were scattered from proton targets (NH153 dynamically polarized along the beam direction) and detected with CLAS. From the measured double spin asymmetries, we extracted virtual photon asymmetries A1p and A2p and spin structure functions g1p and g2p over a wide kinematic range (0.05 GeV21.08 GeV 1p. We compare our final results with various theoretical models and expectations, as well as with parametrizations of the world data. Our data, with their precision and dense kinematic coverage, are able to constrain fits of polarized parton distributions, test pQCD predictions for quark polarizations at large x , offer a better understanding of quark-hadron duality, and provide more precise values of higher twist matrix elements in the framework of the operator product expansion.

Enhanced Spin-Orbit Torque via Modulation of Spin Current Absorption

KAUST Repository

Qiu, Xuepeng

2016-11-18

The magnitude of spin-orbit torque (SOT), exerted to a ferromagnet (FM) from an adjacent heavy metal (HM), strongly depends on the amount of spin current absorbed in the FM. We exploit the large spin absorption at the Ru interface to manipulate the SOTs in HM/FM/Ru multilayers. While the FM thickness is smaller than its spin dephasing length of 1.2 nm, the top Ru layer largely boosts the absorption of spin currents into the FM layer and substantially enhances the strength of SOT acting on the FM. Spin-pumping experiments induced by ferromagnetic resonance support our conclusions that the observed increase in the SOT efficiency can be attributed to an enhancement of the spin-current absorption. A theoretical model that considers both reflected and transmitted mixing conductances at the two interfaces of FM is developed to explain the results.

Geometrical spin symmetry and spin

International Nuclear Information System (INIS)

Pestov, I. B.

2011-01-01

Unification of General Theory of Relativity and Quantum Mechanics leads to General Quantum Mechanics which includes into itself spindynamics as a theory of spin phenomena. The key concepts of spindynamics are geometrical spin symmetry and the spin field (space of defining representation of spin symmetry). The essence of spin is the bipolar structure of geometrical spin symmetry induced by the gravitational potential. The bipolar structure provides a natural derivation of the equations of spindynamics. Spindynamics involves all phenomena connected with spin and provides new understanding of the strong interaction.

Effect of the magnetic dipole interaction on a spin-1 system

Science.gov (United States)

Hu, Fangqi; Jia, Wei; Zhao, Qing

2018-05-01

We consider a hybrid system composed of a spin-1 triplet coupled to a nuclear spin. We study the effect of the axisymmetric and the quadrupole term of the magnetic dipole interaction between the two electrons forming the triplet on the energy spectrum in a static magnetic field. The energy spectrum obtained by directly diagonalizing the Hamiltonian of the system shows that these two terms not only remove the special crossings that appear in the absence of the magnetic dipole interaction, but also produce new (avoided) crossings by lifting the relevant levels. Specially, the gaps between the avoided crossing levels increase with the strength of the quadrupole term. In order to accurately illustrate these effects, we present the results for the discriminant and von Neumann entropy of one electron interacting with the rest of the whole system. Finally, by numerically solving the time-dependent Schrödinger equations of the system, we discover that the polarization oscillation of electron and nuclear spin is in-phase and the total average longitudinal spin is not conserved at location of avoided crossing, but the two results are opposite beyond that.

SU (N ) spin-wave theory: Application to spin-orbital Mott insulators

Science.gov (United States)

Dong, Zhao-Yang; Wang, Wei; Li, Jian-Xin

2018-05-01

We present the application of the SU (N ) spin-wave theory to spin-orbital Mott insulators whose ground states exhibit magnetic orders. When taking both spin and orbital degrees of freedom into account rather than projecting Hilbert space onto the Kramers doublet, which is the lowest spin-orbital locked energy levels, the SU (N ) spin-wave theory should take the place of the SU (2 ) one due to the inevitable spin-orbital multipole exchange interactions. To implement the application, we introduce an efficient general local mean-field method, which involves all local fluctuations, and develop the SU (N ) linear spin-wave theory. Our approach is tested firstly by calculating the multipolar spin-wave spectra of the SU (4 ) antiferromagnetic model. Then, we apply it to spin-orbital Mott insulators. It is revealed that the Hund's coupling would influence the effectiveness of the isospin-1 /2 picture when the spin-orbital coupling is not large enough. We further carry out the SU (N ) spin-wave calculations of two materials, α -RuCl3 and Sr2IrO4 , and find that the magnonic and spin-orbital excitations are consistent with experiments.

Spin-1 and -2 bilayer Bethe lattice: A Monte Carlo study

International Nuclear Information System (INIS)

Masrour, R.; Jabar, A.; Benyoussef, A.; Hamedoun, M.

2016-01-01

The magnetic behaviors of bilayer with spin-1 and 2 Ising model on the Bethe lattice are investigated using the Monte Carlo simulations. The thermal magnetizations, the magnetic susceptibilities and the transition temperature of the bilayer spin-1 and 2 on the Bethe lattice are studied for different values of crystal field and intralayer coupling constants of the two layers and interlayer coupling constant between the layers. The thermal and magnetic hysteresis cycles are given for different values of the crystal field, for different temperatures and for different exchange interactions. - Highlights: • The magnetic properties of bilayer on the Bethe lattice have been investigated. • The transition temperature has been deduced. • The magnetic coercive filed has been established.

Spin-1 and -2 bilayer Bethe lattice: A Monte Carlo study

Energy Technology Data Exchange (ETDEWEB)

Masrour, R., E-mail: rachidmasrour@hotmail.com [Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, 63 46000 Safi (Morocco); Laboratoire de Magnétisme et Physique des Hautes Energies L.M.P.H.E.URAC 12, Université Mohammed V, Faculté des Sciences, B.P. 1014 Rabat (Morocco); Jabar, A. [Laboratoire de Magnétisme et Physique des Hautes Energies L.M.P.H.E.URAC 12, Université Mohammed V, Faculté des Sciences, B.P. 1014 Rabat (Morocco); Benyoussef, A. [Laboratoire de Magnétisme et Physique des Hautes Energies L.M.P.H.E.URAC 12, Université Mohammed V, Faculté des Sciences, B.P. 1014 Rabat (Morocco); Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Hassan II Academy of Science and Technology, Rabat (Morocco); Hamedoun, M. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco)

2016-03-01

The magnetic behaviors of bilayer with spin-1 and 2 Ising model on the Bethe lattice are investigated using the Monte Carlo simulations. The thermal magnetizations, the magnetic susceptibilities and the transition temperature of the bilayer spin-1 and 2 on the Bethe lattice are studied for different values of crystal field and intralayer coupling constants of the two layers and interlayer coupling constant between the layers. The thermal and magnetic hysteresis cycles are given for different values of the crystal field, for different temperatures and for different exchange interactions. - Highlights: • The magnetic properties of bilayer on the Bethe lattice have been investigated. • The transition temperature has been deduced. • The magnetic coercive filed has been established.

The goldstino brane, the constrained superfields and matter in N=1 supergravity

International Nuclear Information System (INIS)

Bandos, Igor; Heller, Markus; Kuzenko, Sergei M.; Martucci, Luca; Sorokin, Dmitri

2016-01-01

We show that different (brane and constrained superfield) descriptions for the Volkov-Akulov goldstino coupled to N=1, D=4 supergravity with matter produce similar wide classes of models with spontaneously broken local supersymmetry and discuss the relation between the different formulations. As with the formulations with irreducible constrained superfields, the geometric goldstino brane approach has the advantage of being manifestly off-shell supersymmetric without the need to introduce auxiliary fields. It provides an explicit solution of the nilpotent superfield constraints and avoids issues with non-Gaussian integration of auxiliary fields. We describe general couplings of the supersymmetry breaking sector, including the goldstino and other non-supersymmetric matter, to supergravity and matter supermultiplets. Among various examples, we discuss a goldstino brane contribution to the gravitino mass term and the supersymmetrization of the anti-D3-brane contribution to the effective theory of type IIB warped flux compactifications.

The goldstino brane, the constrained superfields and matter in N=1 supergravity

Energy Technology Data Exchange (ETDEWEB)

Bandos, Igor [Department of Theoretical Physics, University of the Basque Country UPV/EHU,P.O. Box 644, 48080 Bilbao (Spain); IKERBASQUE, Basque Foundation for Science,48011, Bilbao (Spain); Heller, Markus [Dipartimento di Fisica e Astronomia “Galileo Galilei' , Università degli Studi di Padova,Via Marzolo 8, 35131 Padova (Italy); Institut für Theoretische Physik, Ruprecht-Karls-Universität,Philosophenweg 19, 69120 Heidelberg (Germany); Kuzenko, Sergei M. [School of Physics M013, The University of Western Australia35 Stirling Highway, Crawley W.A. 6009 (Australia); Martucci, Luca [Dipartimento di Fisica e Astronomia “Galileo Galilei' , Università degli Studi di Padova,Via Marzolo 8, 35131 Padova (Italy); INFN - Sezione di Padova,Via Marzolo 8, 35131 Padova (Italy); Sorokin, Dmitri [INFN - Sezione di Padova,Via Marzolo 8, 35131 Padova (Italy); Dipartimento di Fisica e Astronomia “Galileo Galilei' , Università degli Studi di Padova,Via Marzolo 8, 35131 Padova (Italy)

2016-11-21

We show that different (brane and constrained superfield) descriptions for the Volkov-Akulov goldstino coupled to N=1, D=4 supergravity with matter produce similar wide classes of models with spontaneously broken local supersymmetry and discuss the relation between the different formulations. As with the formulations with irreducible constrained superfields, the geometric goldstino brane approach has the advantage of being manifestly off-shell supersymmetric without the need to introduce auxiliary fields. It provides an explicit solution of the nilpotent superfield constraints and avoids issues with non-Gaussian integration of auxiliary fields. We describe general couplings of the supersymmetry breaking sector, including the goldstino and other non-supersymmetric matter, to supergravity and matter supermultiplets. Among various examples, we discuss a goldstino brane contribution to the gravitino mass term and the supersymmetrization of the anti-D3-brane contribution to the effective theory of type IIB warped flux compactifications.

Spin-4 extended conformal algebras

International Nuclear Information System (INIS)

Kakas, A.C.

1988-01-01

We construct spin-4 extended conformal algebras using the second hamiltonian structure of the KdV hierarchy. In the presence of a U(1) current a family of spin-4 algebras exists but the additional requirement that the spin-1 and spin-4 currents commute fixes the algebra uniquely. (orig.)

Higher spin currents in the critical O(N) vector model at 1/N{sup 2}

Energy Technology Data Exchange (ETDEWEB)

Manashov, A.N. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Skvortsov, E.D. [Munich Univ. (Germany). Arnold Sommerfeld Center for Theoretical Physics; Lebedev Institute of Physics, Moscow (Russian Federation); Strohmaier, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik

2017-06-15

We calculate the anomalous dimensions of higher spin singlet currents in the critical O(N) vector model at order 1/N{sup 2}. The results are shown to be in agreement with the four-loop perturbative computation in φ{sup 4} theory in 4-2ε dimensions. It is known that the order 1/N anomalous dimensions of higher-spin currents happen to be the same in the Gross-Neveu and the critical vector model. On the contrary, the order 1/N{sup 2} corrections are different. The results can also be interpreted as a prediction for the two-loop computation in the dual higher-spin gravity.

Critical behavior of the quantum spin- {1}/{2} anisotropic Heisenberg model

Science.gov (United States)

Sousa, J. Ricardo de

A two-step renormalization group approach - a decimation followed by an effective field renormalization group (EFRG) - is proposed in this work to study the critical behavior of the quantum spin- {1}/{2} anisotropic Heisenberg model. The new method is illustrated by employing approximations in which clusters with one, two and three spins are used. The values of the critical parameter and critical exponent, in two- and three-dimensional lattices, for the Ising and isotropic Heisenberg limits are calculated and compared with other renormalization group approaches and exact (or series) results.

Weyl and transverse diffeomorphism invariant spin-2 models in D = 2 + 1

Energy Technology Data Exchange (ETDEWEB)

Dalmazi, Denis; Mendonca, E.L. [UNESP-Campus de Guaratingueta-DFQ, Guaratingueta, SP (Brazil); ICTP South American Institute for Fundamental Research, IFT-UNESP, Sao Paulo, SP (Brazil); Santos, A.L.R. dos [UNESP-Campus de Guaratingueta-DFQ, Guaratingueta, SP (Brazil); Ghosh, Subir [ICTP South American Institute for Fundamental Research, IFT-UNESP, Sao Paulo, SP (Brazil); Indian Statistical Institute, Physics and Applied Mathematics Unit, Kolkata (India)

2017-09-15

There are two covariant descriptions of massless spin-2 particles in D = 3 + 1 via a symmetric rank-2 tensor: the linearized Einstein-Hilbert (LEH) theory and the Weyl plus transverse diffeomorphism (WTDIFF) invariant model. From the LEH theory one can obtain the linearized new massive gravity (NMG) in D = 2 + 1 via Kaluza-Klein dimensional reduction followed by a dual master action. Here we show that a similar route takes us from the WTDIFF model to a linearized scalar-tensor NMG which belongs to a larger class of consistent spin-0 modifications of NMG. We also show that a traceless master action applied to a parity singlet furnishes two new spin-2 self-dual models. Moreover, we examine the singular replacement h{sub μν} → h{sub μν} - η{sub μν}h/D and prove that it leads to consistent massive spin-2 models in D = 2 + 1. They include linearized versions of unimodular topologically massive gravity (TMG) and unimodular NMG. Although the free part of those unimodular theories are Weyl invariant, we do not expect any improvement in the renormalizability. Both the linearized K-term (in NMG) and the linearized gravitational Chern-Simons term (in TMG) are invariant under longitudinal reparametrizations δh{sub μν} = ∂{sub μ}∂{sub ν}ζ, which is not a symmetry of the WTDIFF Einstein-Hilbert term. Therefore, we still have one degree of freedom whose propagator behaves like 1/p{sup 2} for large momentum. (orig.)

Internet gaming disorder: Inadequate diagnostic criteria wrapped in a constraining conceptual model.

Science.gov (United States)

Starcevic, Vladan

2017-06-01

Background and aims The paper "Chaos and confusion in DSM-5 diagnosis of Internet Gaming Disorder: Issues, concerns, and recommendations for clarity in the field" by Kuss, Griffiths, and Pontes (in press) critically examines the DSM-5 diagnostic criteria for Internet gaming disorder (IGD) and addresses the issue of whether IGD should be reconceptualized as gaming disorder, regardless of whether video games are played online or offline. This commentary provides additional critical perspectives on the concept of IGD. Methods The focus of this commentary is on the addiction model on which the concept of IGD is based, the nature of the DSM-5 criteria for IGD, and the inclusion of withdrawal symptoms and tolerance as the diagnostic criteria for IGD. Results The addiction framework on which the DSM-5 concept of IGD is based is not without problems and represents only one of multiple theoretical approaches to problematic gaming. The polythetic, non-hierarchical DSM-5 diagnostic criteria for IGD make the concept of IGD unacceptably heterogeneous. There is no support for maintaining withdrawal symptoms and tolerance as the diagnostic criteria for IGD without their substantial revision. Conclusions The addiction model of IGD is constraining and does not contribute to a better understanding of the various patterns of problematic gaming. The corresponding diagnostic criteria need a thorough overhaul, which should be based on a model of problematic gaming that can accommodate its disparate aspects.

Spin dynamics of the itinerant helimagnet MnSi studied by positive muon spin relaxation

International Nuclear Information System (INIS)

Kadono, R.; Matsuzaki, T.; Yamazaki, T.; Kreitzman, S.R.; Brewer, J.H.

1990-03-01

The local magnetic fields and spin dynamics of the itinerant helimagnet MnSi(T c ≅ 29.5 K) have been studied experimentally using positive muon spin rotation/relaxation (μ + SR) methods. In the ordered phase (T c ), zero-field μSR was used to measure the hyperfine fields at the muon sites as well as the muon spin-lattice relaxation time T 1 μ . Two magnetically inequivalent interstitial μ + sites were found with hyperfine coupling constants A hf (1) = -3.94 kOe/μ B and A hf (2) = -6.94 kOe/μ B , respectively. In the paramagnetic phase (T > T c ), the muon-nuclear spin double relaxation technique was used to simultaneously but independently determine the spin-lattice relaxation time T 1 Mn of 55 Mn spins and that of positive muons (T 1 μ ) over a wide temperature range (T c 1 Mn and T 1 μ in both phases shows systematic deviations from the predictions of self-consistent renormalization (SCR) theory. (author)

Glassy dielectric response in Tb2NiMnO6 double perovskite with similarities to a Griffiths phase

Science.gov (United States)

Nhalil, Hariharan; Nair, Harikrishnan S.; Bhat, H. L.; Elizabeth, Suja

2013-12-01

Results of frequency-dependent and temperature-dependent dielectric measurements performed on the double-perovskite Tb2NiMnO6 are presented. The real (\\epsilon_1 (f,T)) and imaginary (\\epsilon_2 (f,T)) parts of dielectric permittivity show three plateaus suggesting dielectric relaxation originating from the bulk, grain boundaries and the sample-electrode interfaces, respectively. The \\epsilon_1 (f,T) and \\epsilon_2 (f,T) are successfully simulated by a RC circuit model. The complex plane of impedance, Z'\\text{-}Z'' , is simulated using a series network with a resistor R and a constant phase element. Through the analysis of \\epsilon (f,T) using the modified Debye model, two different relaxation time regimes separated by a characteristic temperature, T^* , are identified. The temperature variation of R and C corresponding to the bulk and the parameter α from modified Debye fit lend support to this hypothesis. Interestingly, the T^* compares with the Griffiths temperature for this compound observed in magnetic measurements. Though these results cannot be interpreted as magnetoelectric coupling, the relationship between lattice and magnetism is markedly clear. We assume that the observed features have their origin in the polar nanoregions which originate from the inherent cationic defect structure of double perovskites.

Variational discussion of the Hamiltonian Z(N) spin model in 1+1 and 2+1 dimensions

International Nuclear Information System (INIS)

Jengo, R.; Masperi, L.; Omero, C.

1982-01-01

We study the Z(N) spin model, as well as its limiting forms for N → infinity by means of a variational approach. We find, for 1 + 1 dimensions, the two transitions of the model separating the disordered, massless and ordered phases. In the case of 2 + 1 dimensions, we obtain only the disorder-order phase transition which implies for N → infinity single confining phase for the dual U(1) gauge theory. (orig.)

Weak value distributions for spin 1/2

Science.gov (United States)

Berry, M. V.; Dennis, M. R.; McRoberts, B.; Shukla, P.

2011-05-01

The simplest weak measurement is of a component of spin 1/2. For this observable, the probability distributions of the real and imaginary parts of the weak value, and their joint probability distribution, are calculated exactly for pre- and postselected states uniformly distributed over the surface of the Poincaré-Bloch sphere. The superweak probability, that the real part of the weak value lies outside the spectral range, is 1/3. This case, with just two eigenvalues, complements our previous calculation (Berry and Shukla 2010 J. Phys. A: Math. Theor. 43 354024) of the universal form of the weak value probability distribution for an operator with many eigenvalues.

Weak value distributions for spin 1/2

International Nuclear Information System (INIS)

Berry, M V; Dennis, M R; McRoberts, B; Shukla, P

2011-01-01

The simplest weak measurement is of a component of spin 1/2. For this observable, the probability distributions of the real and imaginary parts of the weak value, and their joint probability distribution, are calculated exactly for pre- and postselected states uniformly distributed over the surface of the Poincare-Bloch sphere. The superweak probability, that the real part of the weak value lies outside the spectral range, is 1/3. This case, with just two eigenvalues, complements our previous calculation (Berry and Shukla 2010 J. Phys. A: Math. Theor. 43 354024) of the universal form of the weak value probability distribution for an operator with many eigenvalues.

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.

Modeling the Anomalous Microwave Emission with Spinning Nanoparticles: No PAHs Required

Energy Technology Data Exchange (ETDEWEB)

Hensley, Brandon S. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Draine, B. T., E-mail: brandon.s.hensley@jpl.nasa.gov [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2017-02-20

In light of recent observational results indicating an apparent lack of correlation between the anomalous microwave emission (AME) and mid-infrared emission from polycyclic aromatic hydrocarbons, we assess whether rotational emission from spinning silicate and/or iron nanoparticles could account for the observed AME without violating observational constraints on interstellar abundances, ultraviolet extinction, and infrared emission. By modifying the SpDust code to compute the rotational emission from these grains, we find that nanosilicate grains could account for the entirety of the observed AME, whereas iron grains could be responsible for only a fraction, even for extreme assumptions on the amount of interstellar iron concentrated in ultrasmall iron nanoparticles. Given the added complexity of contributions from multiple grain populations to the total spinning dust emission, as well as existing uncertainties due to the poorly constrained grain size, charge, and dipole moment distributions, we discuss generic, carrier-independent predictions of spinning dust theory and observational tests that could help identify the AME carrier(s).

Spin effects in high- and low-field magnetotransport experiments in semimagnetic Cd1-xMnxTe heterostructures